spore: profile id: tool-steel-12738 spore_version: 0.2 family: tool-steels name: 1.2738 plastic mould steel (40CrMnNiMo8-6-4, AISI P20+Ni) abbreviation: 1.2738 (P20+Ni) role: plastic mould steel category: metals type: steels-and-stainless summary: 1.2738 (40CrMnNiMo8-6-4, printed as AISI / SAE P20+Ni) is a pre-hardened, low-sulphur plastic mould steel with about 1 percent nickel. It is supplied quenched and tempered at about 280 to 330 HB, so mould blocks can be machined and polished without a further heat treatment, and the nickel improves through-hardening in sections above 400 mm. It is not stainless (1.8 to 2.1 percent chromium), and Abrams gives it only a certain degree of corrosion resistance. best_for: Large plastic injection-mould blocks, cores and frames that are machined in the supplied condition and then polished, and hydroforming tools and dies (Dörrenberg; Industeel; Oberste-Beulmann; Abrams). weakest_at: 'Corrosion resistance. Abrams says the grade has a certain degree of corrosion resistance but is not stainless: 1.8 to 2.1 percent chromium is far below the 10.5 percent it gives as the minimum for stainless steel. Reheating or tempering at 600 °C or above lowers hardness.' identity: formula: 'Fe balance; 0.35 to 0.45 C, 0.20 to 0.40 Si, 1.30 to 1.60 Mn, 1.80 to 2.10 Cr, 0.15 to 0.25 Mo, 0.90 to 1.20 Ni, 0.030 max P, 0.030 max S (wt%, minimum and maximum as printed by Industeel; Abrams prints the same ranges). Typical analysis (Industeel): 0.40 C, 0.30 Si, 1.50 Mn, 1.90 Cr, 1.00 Ni, 0.20 Mo, 0.005 S, 0.012 P.' source: industeel-ds2738 where: CHEMICAL ANALYSIS, WEIGHT PERCENT, Mini, Typical and Max rows designations: - system: EN code: '1.2738' source: dorr-12738 where: Header, material number 1.2738 (Industeel prints Werkstoff W1.2738) - system: EN name code: 40CrMnNiMo8-6-4 source: ober-12738 where: Standards table, EN ISO 4957 row - system: AISI / SAE code: P20+Ni source: abrams-12738 where: Product title block, AISI / SAE P20+Ni - system: AISI code: P20+Ni source: ober-12738 where: Standards table, AISI row (printed P 20+Ni) - system: AFNOR code: 40CMND8 source: ober-12738 where: Standards table, AFNOR row - system: GOST code: 4Х2ГНМ source: ober-12738 where: Standards table, GOST row - system: ISO code: '4957' note: standard number that covers the grade, not a grade code source: dorr-12738 where: First paragraph, DIN EN ISO 4957 tags: environments: [] stresses: [] applications: - mechanisms - structures properties: - benchmark: density label: Density, typical at room temperature value: 7.8 unit: g/cm3 scope: material conditions: condition: typical value, heat-treatment state not stated on the page temperature: room temperature (as printed) method: Abrams web page, density paragraph, printed as 7.80 g/cm 3 at room temperature status: ground source: abrams-12738 where: Steel density paragraph, 1.2738 FAQ block - benchmark: thermal_conductivity label: Thermal conductivity, room temperature value: 34.5 unit: W/m.K scope: material conditions: condition: heat-treatment state not stated on the page temperature: room temperature (as printed) unit_in_source: W/(m*K) method: Abrams web page, heat conductivity paragraph, printed as 34.5 W/(m*K) at room temperature status: ground source: abrams-12738 where: Heat conductivity paragraph, 1.2738 FAQ block - benchmark: thermal_conductivity label: Thermal conductivity at 20 °C, typical value: 29 unit: W/m.K scope: material conditions: condition: typical values, heat-treatment state not stated temperature: 20 °C unit_in_source: W.m-1.K-1 method: Physical properties table, thermal conductivity column at 20 °C, typical values, as printed status: ground source: industeel-ds2738 where: PHYSICAL PROPERTIES table, thermal conductivity at 20°C - benchmark: cte label: Coefficient of thermal expansion, 20 to 100 °C, typical value: 11.5 unit: ppm/K scope: material conditions: condition: typical values, heat-treatment state not stated temperature: 20 to 100 °C unit_in_source: 10^-6.K^-1 (same number as ppm/K) method: Physical properties table, thermal expansion coefficient, 20-100 °C column, as printed status: ground source: industeel-ds2738 where: PHYSICAL PROPERTIES table, thermal expansion coefficient, 20-100°C column - benchmark: cte label: Coefficient of thermal expansion, 20 to 400 °C, typical value: 12.6 unit: ppm/K scope: material conditions: condition: typical values, heat-treatment state not stated temperature: 20 to 400 °C unit_in_source: 10^-6.K^-1 (same number as ppm/K) method: Physical properties table, thermal expansion coefficient, 20-400 °C column, as printed status: ground source: industeel-ds2738 where: PHYSICAL PROPERTIES table, thermal expansion coefficient, 20-400°C column - benchmark: specific_heat label: Specific heat capacity, typical value: 470 unit: J/kg.K scope: material conditions: condition: typical values, temperature not stated unit_in_source: J/kg.°C method: Physical properties table, specific heat column, as printed status: ground source: industeel-ds2738 where: PHYSICAL PROPERTIES table, specific heat column - benchmark: elastic_modulus label: Modulus of elasticity, typical value: 205 unit: GPa scope: material conditions: condition: quenched and tempered, 300 HB typical (as printed) temperature: not stated method: Mechanical properties table, elastic modulus column, 300 HB row, typical values status: ground source: industeel-ds2738 where: MECHANICAL PROPERTIES table, elastic modulus GPa, 300 HB row - benchmark: elastic_modulus label: Modulus of elasticity, as printed by Abrams value: 205 unit: GPa scope: material conditions: condition: heat-treatment state not stated on the page unit_in_source: kN/mm2 (same number as GPa) method: Abrams web page, paragraph on the modulus of elasticity (German text), printed as 205 kN/mm2 status: ground source: abrams-12738 where: Elastizitaetsmodul (e-Modul) paragraph, 1.2738 FAQ block - benchmark: yield_strength label: Yield strength Rp0.2, typical value: 826 unit: MPa scope: material conditions: condition: quenched and tempered, 300 HB typical (as printed) test: tensile, method not stated method: Mechanical properties table, Rp 0.2 column, 300 HB row, typical values status: ground source: industeel-ds2738 where: MECHANICAL PROPERTIES table, Rp 0.2 yield strength MPa, 300 HB row - benchmark: ultimate_tensile_strength label: Tensile strength Rm, typical value: 993 unit: MPa scope: material conditions: condition: quenched and tempered, 300 HB typical (as printed) test: tensile, method not stated method: Mechanical properties table, Rm column, 300 HB row, typical values status: ground source: industeel-ds2738 where: MECHANICAL PROPERTIES table, Rm tensile strength MPa, 300 HB row - benchmark: ultimate_tensile_strength label: Tensile strength, approximate, as delivered value: 1100 unit: MPa scope: material conditions: condition: as-delivered tempered condition, printed as approximate test: not stated method: Abrams web page, tensile strength paragraph, printed as approx. 1100 N/mm2 upon delivery status: ground note: approximate value as printed; the hardness it relates to is not stated source: abrams-12738 where: Tensile strength paragraph, 1.2738 FAQ block - benchmark: ultimate_tensile_strength label: Tensile strength converted from hardness value: 950 value_high: 1100 bound: range unit: MPa scope: material conditions: condition: delivered quenched and tempered, 280 to 325 HB (as printed by Dörrenberg) test: none, converted from hardness method: Converted from hardness by DIN EN ISO 18265 Table A.1, as printed by Dörrenberg (950 - 1100 N/mm2); not a tensile test status: calculated source: dorr-12738 where: Condition of delivery row, 280 - 325 HB (950 - 1100 N/mm2) - benchmark: elongation label: Elongation, typical value: 17 unit: '%' scope: material conditions: condition: quenched and tempered, 300 HB typical (as printed) gauge: not stated on the datasheet method: Mechanical properties table, elongation column, 300 HB row status: ground source: industeel-ds2738 where: MECHANICAL PROPERTIES table, elongation %, 300 HB row - benchmark: reduction_of_area label: Reduction of area Z, typical value: 49 unit: '%' scope: material conditions: condition: quenched and tempered, 300 HB typical (as printed) method: Mechanical properties table, reduction of area Z column, 300 HB row status: ground source: industeel-ds2738 where: MECHANICAL PROPERTIES table, reduction of area Z %, 300 HB row - benchmark: charpy_v_impact_energy label: Impact energy KCV at 20 °C, typical value: 25 unit: J scope: material conditions: condition: quenched and tempered, 300 HB typical (as printed) temperature: 20 °C method: Mechanical properties table, KCV 20 °C column, 300 HB row status: ground source: industeel-ds2738 where: MECHANICAL PROPERTIES table, KCV 20°C (J), 300 HB row - benchmark: hardness_brinell label: Hardness, typical prehardened value: 300 unit: HB scope: material conditions: condition: quenched and tempered, prehardened (headline 300 HB, 32 HRC) scale: HB method: Headline and mechanical properties table, hardness HB row, typical values status: ground source: industeel-ds2738 where: Headline 300HB (32 HRC) and MECHANICAL PROPERTIES table, hardness 300 HB row - benchmark: hardness_brinell label: Hardness as delivered, Industeel value: 290 value_high: 330 bound: range unit: HB scope: material conditions: condition: quenched and tempered, delivery condition (as printed) scale: HB method: Mechanical properties text, delivered quenched and tempered to 290 - 330 HB status: ground source: industeel-ds2738 where: MECHANICAL PROPERTIES text, first sentence - benchmark: hardness_brinell label: Hardness as delivered, Dörrenberg value: 280 value_high: 325 bound: range unit: HB scope: material conditions: condition: quenched and tempered, condition of delivery (as printed) scale: HB method: Condition of delivery row, as printed (280 - 325 HB) status: ground source: dorr-12738 where: Condition of delivery row, quenched and tempered 280 - 325 HB - benchmark: hardness_brinell label: Hardness, supply condition quenched and tempered, Oberste-Beulmann value: 290 value_high: 325 bound: range unit: HB scope: material conditions: condition: supply condition quenched and tempered (as printed) scale: HB method: Data sheet table, Hardness (HB) row, as printed (290 - 325) status: ground source: ober-12738 where: Hardness (HB) row, supply condition quenched+tempered - benchmark: hardness_brinell label: Hardness, delivery condition, maximum value: 325 bound: upper unit: HB scope: material conditions: condition: delivery condition, tempered (as printed) scale: HB method: Standard values table, delivery condition maximum 325 HB status: ground source: abrams-12738 where: 1.2738 standard values, delivery condition row - benchmark: hardness_brinell label: Hardness after soft annealing, maximum value: 235 bound: upper unit: HB scope: material conditions: condition: soft annealed at 710 to 740 °C, cooled slowly in the furnace scale: HB method: Heat treatment table, soft annealing row, max. 235 HB as printed status: ground source: dorr-12738 where: Heat treatment table, soft annealing row, max 235 HB - benchmark: hardness_rockwell_c label: Hardness as delivered, HRC value: 30 value_high: 35 bound: range unit: HRC scope: material conditions: condition: quenched and tempered, delivery condition (as printed) scale: HRC method: Mechanical properties text, delivered quenched and tempered to 290 - 330 HB (30 - 35 HRC) status: ground source: industeel-ds2738 where: MECHANICAL PROPERTIES text, HRC equivalent in brackets - benchmark: hardness_rockwell_c label: Hardness, typical prehardened value: 32 unit: HRC scope: material conditions: condition: prehardened grade, typical (headline 300 HB / 32 HRC) scale: HRC method: Headline, as printed status: ground source: industeel-ds2738 where: Headline 300HB (32 HRC) - benchmark: hardness_rockwell_c label: Working hardness range value: 32 value_high: 50 bound: range unit: HRC scope: material conditions: condition: supplied tempered at about 32 HRC, up to 50 HRC in working condition (as printed) scale: HRC method: Standard values table and working hardness paragraph, as printed (ca. 32 HRC to 50 HRC) status: ground source: abrams-12738 where: 1.2738 standard values, working hardness row - benchmark: hardness_rockwell_c label: Hardness after hardening and quenching value: 51 unit: HRC scope: material conditions: condition: after hardening at 840 to 870 °C and quenching in polymer or oil (re-hardened, not the supplied condition) scale: HRC method: Heat treatment table, hardening row, hardness after quenching 51 HRC, as printed status: ground source: abrams-pdf-12738 where: Heat treatment table, hardening row, hardness after quenching - benchmark: hardness_rockwell_c label: Hardness after tempering at 500 °C value: 42 unit: HRC scope: material conditions: condition: after hardening, tempered at 500 °C (tempering chart; hold time not printed on the chart) scale: HRC method: Tempering chart, 500 °C column, as printed (Oberste-Beulmann prints the same chart values) status: ground source: abrams-pdf-12738 where: Heat treatment, tempering chart, 500 °C column - benchmark: hardness_rockwell_c label: Hardness after tempering at 600 °C value: 39 unit: HRC scope: material conditions: condition: after hardening, tempered at 600 °C (tempering chart; hold time not printed on the chart) scale: HRC method: Tempering chart, 600 °C column, as printed (Oberste-Beulmann prints the same chart values) status: ground source: abrams-pdf-12738 where: Heat treatment, tempering chart, 600 °C column - benchmark: hardness_rockwell_c label: Hardness after tempering at 700 °C value: 28 unit: HRC scope: material conditions: condition: after hardening, tempered at 700 °C (tempering chart; hold time not printed on the chart) scale: HRC method: Tempering chart, 700 °C column, as printed (Oberste-Beulmann prints the same chart values) status: ground source: abrams-pdf-12738 where: Heat treatment, tempering chart, 700 °C column - benchmark: through_hardening_section label: Section above which nickel improves through-hardening value: 400 bound: lower unit: mm scope: material conditions: condition: statement for dimensions above 400 mm; no hardness depth printed method: Steel properties text, as printed (large dimensions above 400 mm); a section-size statement, not a measured depth status: ground source: dorr-12738 where: Steel properties text, first paragraph (>400 mm) corrosion: - environment: Humid or wet storage, or service with no surface protection headline: Abrams says 1.2738 is not stainless and has only a certain degree of corrosion resistance. effect: Abrams says the grade has a certain degree of corrosion resistance, but to be completely corrosion resistant a steel needs at least 10.5 percent chromium, and 1.2738 has 1.8 to 2.1 percent. No exposure test, humidity or salt data is printed. The low rating is an assistant judgement from this wording. rating: low conditions: basis: datasheet statement test: none printed source: abrams-12738 where: Is the 1.2738 corrosion resistant answer - environment: Nitrided or hard-chrome-plated surface headline: Abrams says nitriding increases corrosion resistance. effect: Abrams says nitriding increases surface hardness, wear resistance and erosion resistance, and also increases corrosion resistance. No corrosion test value is printed. rating: unknown conditions: basis: datasheet statement test: none printed source: abrams-12738 where: 1.2738 surface treatment, Nitriding paragraph - environment: Polished surface with scratches or pits in damp service headline: Abrams says scratches and pits let moisture in and can start corrosion. effect: Abrams says scratches and pitting can be entry points for moisture, which can lead to corrosion over time. It also says over-polishing can cause discolouration, orange peel or pitting. rating: unknown conditions: basis: datasheet statement test: none printed source: abrams-12738 where: 1.2738 Polishing paragraph - environment: PVC and plastics that release aggressive gases during moulding headline: Aços Formosa points these plastics to stainless 1.2316, not to 1.2738. effect: Aços Formosa lists PVC and corrosive plastics under stainless steels for molds, with 1.2316 for these plastics, and lists 1.2738 under the P-20 family for large molds. It gives no corrosion test for 1.2738. rating: unknown conditions: basis: supplier product guidance test: none printed for 1.2738 source: formosa-plastic-molds where: Best Choice For list, Stainless Steels for Molds, and P-20 + Ni row risks: hazards: - text: 'PubChem aggregated GHS record for elemental nickel (CID 935): signal word Danger. 0.1 percent (5 of 4778) of reports say it does not meet GHS criteria. Reported codes include H317, allergic skin reaction (99.9 percent of notifications), H351, suspected of causing cancer (72.9 percent), and H372, organ damage from prolonged or repeated exposure (99.7 percent). The record describes the element, not the steel.' ghs: - H317 - H351 - H372 - H412 source: pc-ni-935 where: Safety and Hazards, GHS Classification - text: 'PubChem aggregated GHS record for elemental chromium (CID 23976): signal word Danger. 50 percent (1202 of 2404) of reports say it does not meet GHS criteria. Reported codes include H317, allergic skin reaction (20.7 percent), H334, allergy or asthma symptoms if inhaled (20.3 percent), and H319, serious eye irritation (19.1 percent). The record describes the element, not the steel.' ghs: - H317 - H319 - H334 source: pc-cr-23976 where: Safety and Hazards, GHS Classification - text: 'PubChem aggregated GHS record for elemental manganese (CID 23930): signal word Danger. 46.1 percent (1429 of 3101) of reports say it does not meet GHS criteria. Reported codes include H228, flammable solid (11.6 percent of notifications), H360, may damage fertility or the unborn child, and H372, organ damage from prolonged exposure. The record describes the element, not the steel.' ghs: - H228 - H360 - H372 source: pc-mn-23930 where: Safety and Hazards, GHS Classification - text: 'PubChem GHS record for elemental molybdenum (CID 23932): 57.4 percent (874 of 1523) of reports say it does not meet GHS criteria. Reported codes include H228, flammable solid (30 percent of notifications), H361, suspected of damaging fertility or the unborn child (29.5 percent), H315, skin irritation, and H335, respiratory irritation. The record describes the element, not the steel.' ghs: - H228 - H315 - H335 - H361 source: pc-mo-23932 where: Safety and Hazards, GHS Classification failure_risks: - mode: Stress corrosion cracking after oil or polymer hardening trigger: Oil or polymer quench without interruption consequence: Oberste-Beulmann prints enhanced stress corrosion cracking susceptibility after oil or polymer hardening and says to interrupt the quench at about 300 to 400 °C. severity: moderate source: ober-12738 where: Quenching row and remarks - mode: Softening when reheated to 600 °C or above trigger: Reheat or tempering at 600 °C or above consequence: The tempering chart gives 42 HRC after 500 °C, 39 HRC after 600 °C and 28 HRC after 700 °C; a reheat to those temperatures lowers hardness. severity: moderate source: abrams-pdf-12738 where: Tempering chart, 500 to 700 °C columns - mode: Loss of hardness on welding above 566 °C trigger: Weld reheat above 566 °C consequence: Abrams says the temperature must not exceed 566 °C, as this would lead to a loss of hardness. severity: moderate source: abrams-12738 where: Welding paragraph - mode: Cracking in welds without pre- and postheat trigger: Welding without preheat and postheat consequence: Industeel says pre- and postheating must be applied to ensure crack-free welds, and recommends GTAW for a clean weld. severity: moderate source: industeel-ds2738 where: WELDING paragraph - mode: Hydrogen embrittlement after hard chrome plating trigger: Hard chromium plating without prompt tempering consequence: Industeel says to temper for about 4 hours at 180 °C after hard chromium plating to avoid hydrogen embrittlement; Abrams says to temper within 4 hours of coating. severity: moderate source: industeel-ds2738 where: SURFACE TREATMENT paragraph - mode: Rehardened white layer after machining trigger: EDM, or grinding and polishing, of the surface consequence: A rehardened surface layer, the white layer, generally appears after grinding and polishing; Industeel says it should be completely removed. severity: low source: industeel-ds2738 where: ELECTRICAL DISCHARGE MACHINING paragraph - mode: Orange peel, waves or pitting from over-polishing trigger: High polishing pressure or long polishing time consequence: Industeel says over-polishing may create defects such as orange peel or waves; Abrams adds pitting and discolouration. severity: low source: industeel-ds2738 where: POLISHING paragraph - mode: Corrosion in humid storage or service trigger: Humid storage or service without surface protection consequence: Chromium at 1.8 to 2.1 percent is below the 10.5 percent that Abrams gives as the minimum for stainless steel, so Abrams gives the grade only a certain degree of corrosion resistance. severity: moderate source: abrams-12738 where: Is the 1.2738 corrosion resistant answer side_effects: - text: The steel is ferromagnetic and can be held on magnetic chucks for grinding; nickel slightly reduces its magnetisability (Abrams). affects: grinding and machining source: abrams-12738 where: Is the 1.2738 magnetisable answer handling: - text: Preheat before use at 250 to 300 °C is recommended (Oberste-Beulmann, remarks). source: ober-12738 where: Remarks, preheating before use - text: Pre-heating steps of about 400 °C and about 650 °C are printed before hardening (Oberste-Beulmann). source: ober-12738 where: Heat treatment table, pre-heating steps - text: Soft anneal at 710 to 740 °C in the furnace with slow cooling; maximum 235 HB afterwards (Dörrenberg). source: dorr-12738 where: Heat treatment table, soft annealing row - text: Stress relieve at 500 to 550 °C for the quenched and tempered condition; in the soft annealed condition, 600 to 650 °C is possible (Dörrenberg). source: dorr-12738 where: Heat treatment table, stress relief annealing row - text: Harden at 840 to 870 °C and quench in oil or a hot bath at 180 to 220 °C (Dörrenberg); Oberste-Beulmann prints 840 to 880 °C. source: dorr-12738 where: Heat treatment table, hardening row - text: 'Temper after hardening: hold about 1 hour per 25 mm of thickness and at least 2 hours, then cool in air (Abrams); Oberste-Beulmann gives 1 hour per 20 mm, at least 2 hours.' source: abrams-12738 where: Tempering paragraph - text: Weld with a preheat of 316 to 371 °C, do not fall below 316 °C, cool to 100 to 150 °C, then heat to 538 °C for one hour per 25 mm of weld depth, without exceeding 566 °C; temper twice if possible (Abrams). source: abrams-12738 where: Welding paragraph - text: Use GTAW with pre- and postheat for crack-free welds (Industeel). source: industeel-ds2738 where: WELDING paragraph - text: Polish with aluminium oxide or diamond paste and avoid over-polishing (Industeel). source: industeel-ds2738 where: POLISHING paragraph - text: After hard chrome plating, temper for about 4 hours at 180 °C (Industeel; Abrams). source: industeel-ds2738 where: SURFACE TREATMENT paragraph - text: Abrams says the grade is supplied in a tempered condition, so heat treatment is not normally required unless a higher hardness or rehardening is wanted. source: abrams-12738 where: Heat treatment paragraph mitigations: - text: Interrupt oil or polymer quenching at about 300 to 400 °C to limit stress corrosion cracking (Oberste-Beulmann). source: ober-12738 where: Quenching row and remarks - text: Nitriding gives a harder surface; Abrams says it also increases corrosion resistance. source: abrams-12738 where: Nitriding paragraph - text: Use the stainless grade 1.2316 for PVC and corrosive plastics (Aços Formosa). source: formosa-plastic-molds where: Best Choice list, Stainless Steels for Molds - text: Very low sulphur (0.005 percent typical, 0.030 percent maximum) supports consistent texturing and polishing (Industeel). source: industeel-ds2738 where: CHEMICAL ANALYSIS S row; text on texturing and polishing uses: - application: mechanisms device: Plastic injection-mould cores and cavities example: 'Industeel: for plastic injection mould cores and cavities, for thermoplastics such as PE, PP and PS.' source: industeel-ds2738 where: For which tools and For which plastics - application: structures device: Large plastic mould blocks and mould frames example: 'Dörrenberg: large plastic moulds highly stressed in the core. Abrams: moulding frames and plastic moulds.' source: dorr-12738 where: Applications row - application: mechanisms device: Die-casting moulds, dies, forging and metal extrusion tools example: Abrams lists plastic moulds, moulding frames, die casting moulds, dies, forging tools, metal extrusion tools, tube presses and hydroforming tools. source: abrams-12738 where: Applications list - application: mechanisms device: Hydroforming tools and dies example: 'Oberste-Beulmann: suitable for large plastic moulds with deep engravings, hydroforming and dies.' source: ober-12738 where: Suitable for row supply: - subject: Chromium abundance: World resources are greater than 12 billion tons of shipping-grade chromite, sufficient for centuries, and 95 percent of them are in Kazakhstan and southern Africa (USGS 2026). US net import reliance was 79 percent of apparent consumption in 2025e. producers: - country: South Africa share_percent: 45.1 year: 2025 - country: Turkey share_percent: 17.6 year: 2025 - country: Kazakhstan share_percent: 13.7 year: 2025 - country: India share_percent: 5.9 year: 2025 - country: Brazil share_percent: 3.9 year: 2025 - country: Zimbabwe share_percent: 3.9 year: 2025 - country: Finland share_percent: 3.7 year: 2025 critical_lists: - list: USGS 2025 List of Critical Minerals (chromium, used in stainless steel) listed: true - list: EU critical raw materials list, fifth list 2023 (34 CRMs; chromium not in the table) listed: false recycling: In 2025, recycled chromium in reported stainless-steel scrap receipts accounted for 21 percent of apparent consumption (USGS 2026). substitutes: - Chromium has no substitute in stainless steel, the leading end use, or in superalloys (USGS 2026). source: usgs-cr-2026 where: Salient Statistics; World Mine Production and Reserves (2025e; shares calculated by Space Mushroom from the printed tonnage over the 51,000 thousand t world total); World Resources; Substitutes; Recycling - subject: Manganese abundance: Land-based manganese resources are large but irregularly distributed, and South Africa accounts for an estimated 70 percent of world resources (USGS 2026). US net import reliance was 100 percent of apparent consumption in each year from 2021 to 2025e. producers: - country: South Africa share_percent: 38 year: 2025 - country: Gabon share_percent: 25 year: 2025 - country: Ghana share_percent: 10 year: 2025 - country: Australia share_percent: 8 year: 2025 - country: Brazil share_percent: 4 year: 2025 - country: India share_percent: 3.95 year: 2025 - country: China share_percent: 3.5 year: 2025 critical_lists: - list: USGS 2025 List of Critical Minerals (manganese, used in steel production and batteries) listed: true - list: EU critical raw materials list, fifth list 2023 (34 CRMs; manganese in the table) listed: true recycling: Manganese is recycled incidentally in ferrous and nonferrous scrap, but scrap recovery specifically for manganese is negligible; it is recovered with iron from steel slag (USGS 2026). substitutes: - Manganese has no satisfactory substitute in its major applications (USGS 2026). source: usgs-mn-2026 where: Salient Statistics; World Mine Production and Reserves (2025e, manganese content; shares calculated by Space Mushroom from the printed tonnage over the 20,000 thousand t world total); World Resources; Substitutes; Recycling - subject: Molybdenum abundance: Identified molybdenum resources are about 5.4 million tons in the United States and about 20 million tons in the rest of the world (USGS 2026). USGS prints US net import reliance as E, meaning net exporter. producers: - country: China share_percent: 37.3 year: 2025 - country: Chile share_percent: 16.2 year: 2025 - country: United States share_percent: 15.4 year: 2025 - country: Peru share_percent: 15 year: 2025 - country: Mexico share_percent: 6.5 year: 2025 critical_lists: - list: USGS 2025 List of Critical Minerals (molybdenum not listed) listed: false - list: EU critical raw materials list, fifth list 2023 (34 CRMs; molybdenum not in the table) listed: false recycling: Molybdenum is recycled as a component of catalysts, ferrous scrap and superalloy scrap; recycled material may be as much as 30 percent of the apparent supply (USGS 2026). substitutes: - There is little substitution for molybdenum in its major application in steels and cast irons; potential substitutes include boron, chromium, niobium and vanadium in alloy steels (USGS 2026). source: usgs-mo-2026 where: Salient Statistics; World Mine Production and Reserves (2025e; shares calculated by Space Mushroom from the printed tonnage over the 260,000 t world total); World Resources; Substitutes; Recycling - subject: Nickel abundance: Global nickel resources are estimated at more than 350 million tons of nickel, with 54 percent in laterites and 35 percent in magmatic sulfide deposits (USGS 2026). US net import reliance was 41 percent of apparent consumption in 2025e. producers: - country: Indonesia share_percent: 66.7 year: 2025 - country: Philippines share_percent: 6.9 year: 2025 - country: Russia share_percent: 5.1 year: 2025 - country: New Caledonia share_percent: 3.6 year: 2025 - country: Canada share_percent: 3.6 year: 2025 - country: China share_percent: 3.1 year: 2025 - country: Brazil share_percent: 1.8 year: 2025 - country: Australia share_percent: 1.2 year: 2025 - country: United States share_percent: 0.3 year: 2025 critical_lists: - list: USGS 2025 List of Critical Minerals (nickel, used to make high-strength steel, and rechargeable batteries) listed: true - list: EU critical raw materials list, fifth list 2023 (34 CRMs; nickel in the table) listed: true recycling: Nickel recovered from scrap accounted for approximately 60 percent of apparent consumption in 2025 (USGS 2026). substitutes: - Low-nickel, duplex or ultrahigh-chromium stainless steels have been substituted for austenitic grades in construction; titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments (USGS 2026). source: usgs-ni-2026 where: Salient Statistics; World Mine Production and Reserves (2025e; shares calculated by Space Mushroom from the printed tonnage over the 3,900,000 t world total); World Resources; Substitutes; Recycling media: [] documents: - title: 'Dörrenberg Edelstahl: 1.2738 (40CrMnNiMo8-6-4) technical data sheet, 02/24' type: datasheet url: https://doerrenberg.de/fileadmin/special_steel/files/pdf_en_products_neues_Design/1.2738_en.pdf year: 2024 - title: 'Industeel (ArcelorMittal): DS-MOLD-2738, W 1.2738 datasheet (03/2022)' type: datasheet url: https://industeel.arcelormittal.com/fichier/ds-mold-2738 year: 2022 - title: 'Wilhelm Oberste-Beulmann: 1.2738 technical data sheet (Sep-18)' type: datasheet url: https://www.oberste-beulmann.de/Dateien/Datenblaetter/1.2738.en.pdf year: 2018 - title: 'ABRAMS Industries: PREMIUM 1.2738 steel, standard values and technical properties (web page)' type: datasheet url: https://eu.abrams-industries.com/steel/premium-12738 - title: 'ABRAMS Industries: PREMIUM 1.2738 steel grade sheet (PDF)' type: datasheet url: https://files.abrams-industries.com/steel/en_eu/1.2738.pdf - title: 'Aços Formosa: Plastic mold steels (P-20 family, P-20 + Ni DIN 1.2738)' type: datasheet url: https://acosformosa.com.br/en/products/plastic-mold-steels/ - title: 'PubChem: Nickel (CID 935), GHS classification' type: database url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/935/JSON/?heading=GHS+Classification - title: 'PubChem: Chromium (CID 23976), GHS classification' type: database url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23976/JSON/?heading=GHS+Classification - title: 'PubChem: Manganese (CID 23930), GHS classification' type: database url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23930/JSON/?heading=GHS+Classification - title: 'PubChem: Molybdenum (CID 23932), GHS classification' type: database url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23932/JSON/?heading=GHS+Classification - title: 'USGS Mineral Commodity Summaries 2026: Chromium' type: report url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf year: 2026 - title: 'USGS Mineral Commodity Summaries 2026: Manganese' type: report url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-manganese.pdf year: 2026 - title: 'USGS Mineral Commodity Summaries 2026: Molybdenum' type: report url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.pdf year: 2026 - title: 'USGS Mineral Commodity Summaries 2026: Nickel' type: report url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf year: 2026 - title: 'USGS: About the 2025 List of Critical Minerals' type: report url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals year: 2025 - title: 'European Commission: Critical raw materials (fifth list 2023, 34 CRMs)' type: report url: https://single-market-economy.ec.europa.eu/sectors/raw-materials/areas-specific-interest/critical-raw-materials_en year: 2023 gaps: - No safety data sheet for the 1.2738 bar was read in this run. The hazard entries are PubChem records for elemental nickel, chromium, manganese and molybdenum, which describe the elements, not the steel. - 'Hardness as delivered differs by source: 280 to 325 HB (Dörrenberg), 290 to 325 HB (Oberste-Beulmann), 290 to 330 HB or 30 to 35 HRC (Industeel), and a maximum of 325 HB (Abrams). All four are kept with their sources; they were not reconciled.' - 'Thermal conductivity differs: 29 W/m.K at 20 °C (Industeel, typical) and 34.5 W/m.K at room temperature (Abrams). Oberste-Beulmann prints 34,5 at 20 °C for the annealed condition and Dörrenberg prints 39,5 W/m.K at 20 °C; those comma-decimal rows are not in properties because the verify step cannot match a comma decimal to a dot value.' - 'Thermal expansion: Oberste-Beulmann (11,1 to 14,9 ppm/K) and Dörrenberg (11,8 to 13,3 ppm/K) print their expansion tables with decimal commas, so those rows are not in properties. Industeel values (11.5 and 12.6 ppm/K) are used.' - 'Specific heat: Abrams prints 0.46 J/kg*K, which conflicts with 470 J/kg.°C from Industeel for the same grade. The Abrams value is not used.' - 'Soft annealing hardness conflicts: Dörrenberg prints a maximum of 235 HB; the Abrams PDF prints max. 325 HB in the same row. The 235 HB value is used; the Abrams row is not.' - 'Stress relief: 500 to 550 °C (Dörrenberg, Oberste-Beulmann, Abrams web page) and 550 to 600 °C (Abrams PDF). Dörrenberg also prints 600 to 650 °C for the soft-annealed condition.' - 'Hardening temperature: 840 to 870 °C (Dörrenberg, Abrams), 840 to 880 °C (Oberste-Beulmann) and about 850 °C (Industeel). Each is kept with its source.' - 'Tempering hold time: 1 hour per 20 mm, at least 2 hours (Oberste-Beulmann); 1 hour per 25 mm, at least 2 hours (Abrams); one hour per inch of total thickness (Industeel).' - 'Section size conflict: Industeel calls the grade a medium-size mould steel, while Dörrenberg, Oberste-Beulmann and Abrams point to large moulds and sections above 400 mm.' - 'Polishing condition: Abrams says the grade polishes well in its annealed delivery condition; Dörrenberg, Industeel, Oberste-Beulmann and the Abrams standard values give quenched and tempered as the supplied condition.' - 'Corrosion: no salt-spray, humidity or exposure test for 1.2738 was printed in the sources read. The corrosion entries are datasheet statements and a supplier product guide, and the ratings are assistant judgements.' - Through-hardening depth in millimetres is not printed. The sources give only the section size above which the nickel benefit applies (above 400 mm). - Tempering-chart values at 100, 200, 300 and 400 °C are printed (Abrams PDF, Oberste-Beulmann) but only the 500, 600 and 700 °C points are used here. - 'Recipe roles are general steel metallurgy unless a source states them (nickel and through-hardening: Dörrenberg and Abrams; very low sulphur and texturing: Industeel).' - Supply shares are calculated by Space Mushroom from the printed USGS tonnage over the printed world totals; they are not printed percentages. - 'Designations: AISI P20+Ni is printed as the same grade by Abrams and Oberste-Beulmann, and as approximately equal by Industeel (AISI about P20 + Ni). No UNS, ASTM or JIS number is printed for 1.2738 in the sources read. 1.2311 and 1.2312 are other grades and their values are not part of this profile.' - Trade and brand names printed on the datasheets (MCMN from Dörrenberg, PREMIUM 1.2738 from Abrams, DS-MOLD-2738 from Industeel) are supplier names and are not listed as designations. - Fracture toughness, Poisson ratio, fatigue, creep and a Charpy curve were not printed in the sources read; the only impact value is the typical KCV of 25 J at 20 °C (Industeel). - Industeel also prints ASTM A578 ultrasonic acceptance and ASTM E45 cleanliness levels for its plate; they are supplier guarantees and are not used as properties. - 'Not reached in this run: Smith Metal Centres, Swiss Steel Formadur 2738 and SIJ SIMOLD 2738 data sheets (the addresses tried gave 404 pages), and the Alro and TotalMateria 1.2738 pages (no address found without a search). No search engine was available in this run.' - No photograph or micrograph of 1.2738 with a licence we could cite was read, so media is empty. sources: dorr-12738: title: 'Dörrenberg Edelstahl: 1.2738 (40CrMnNiMo8-6-4) technical data sheet, 02/24' id: '1.2738' url: https://doerrenberg.de/fileadmin/special_steel/files/pdf_en_products_neues_Design/1.2738_en.pdf year: 2024 kind: datasheet license: supplier datasheet, cited not reproduced industeel-ds2738: title: 'Industeel (ArcelorMittal): DS-MOLD-2738, W 1.2738 datasheet (03/2022)' id: W 1.2738 url: https://industeel.arcelormittal.com/fichier/ds-mold-2738 year: 2022 kind: datasheet license: supplier datasheet, cited not reproduced ober-12738: title: 'Wilhelm Oberste-Beulmann: 1.2738 technical data sheet (Sep-18)' id: 1.2738, Code (SEL) 40CrMnNiMo8-6-4 url: https://www.oberste-beulmann.de/Dateien/Datenblaetter/1.2738.en.pdf year: 2018 kind: datasheet license: supplier datasheet, cited not reproduced abrams-12738: title: 'ABRAMS Industries: PREMIUM 1.2738 steel, standard values and technical properties (web page)' id: PREMIUM 1.2738 url: https://eu.abrams-industries.com/steel/premium-12738 kind: web license: supplier web page, cited not reproduced abrams-pdf-12738: title: 'ABRAMS Industries: PREMIUM 1.2738 steel grade sheet (PDF)' id: PREMIUM 1.2738 url: https://files.abrams-industries.com/steel/en_eu/1.2738.pdf kind: datasheet license: supplier datasheet, cited not reproduced formosa-plastic-molds: title: 'Aços Formosa: Plastic mold steels (P-20 family, P-20 + Ni DIN 1.2738)' id: P-20 + Ni url: https://acosformosa.com.br/en/products/plastic-mold-steels/ kind: web license: supplier web page, cited not reproduced pc-ni-935: title: 'PubChem: Nickel (CID 935), Safety and Hazards, GHS Classification' id: CID 935 url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/935/JSON/?heading=GHS+Classification kind: database license: PubChem terms (public) pc-cr-23976: title: 'PubChem: Chromium (CID 23976), Safety and Hazards, GHS Classification' id: CID 23976 url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23976/JSON/?heading=GHS+Classification kind: database license: PubChem terms (public) pc-mn-23930: title: 'PubChem: Manganese (CID 23930), Safety and Hazards, GHS Classification' id: CID 23930 url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23930/JSON/?heading=GHS+Classification kind: database license: PubChem terms (public) pc-mo-23932: title: 'PubChem: Molybdenum (CID 23932), Safety and Hazards, GHS Classification' id: CID 23932 url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23932/JSON/?heading=GHS+Classification kind: database license: PubChem terms (public) usgs-cr-2026: title: 'USGS Mineral Commodity Summaries 2026: Chromium' id: mcs2026-chromium url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf year: 2026 kind: report license: public domain (USGS) usgs-mn-2026: title: 'USGS Mineral Commodity Summaries 2026: Manganese' id: mcs2026-manganese url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-manganese.pdf year: 2026 kind: report license: public domain (USGS) usgs-mo-2026: title: 'USGS Mineral Commodity Summaries 2026: Molybdenum' id: mcs2026-molybdenum url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-molybdenum.pdf year: 2026 kind: report license: public domain (USGS) usgs-ni-2026: title: 'USGS Mineral Commodity Summaries 2026: Nickel' id: mcs2026-nickel url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf year: 2026 kind: report license: public domain (USGS) usgs-crit-2025: title: 'USGS: About the 2025 List of Critical Minerals' id: 2025 list url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals year: 2025 kind: web license: public domain (USGS) ec-crm-2023: title: 'European Commission: Critical raw materials (fifth list 2023, 34 CRMs)' id: fifth list 2023 url: https://single-market-economy.ec.europa.eu/sectors/raw-materials/areas-specific-interest/critical-raw-materials_en year: 2023 kind: web license: European Commission web page, cited not reproduced license: CC-BY-4.0 updated: '2026-10-24' review: status: draft method: assistant checked_values: 29 unreachable: 0 caveats: 3 note: 'Read by an AI assistant on 2026-10-24 from pages fetched by direct URL in this run; no search engine was available in this run. Caveats: the 1100 MPa tensile value is printed as approximate; the thermal conductivity sources differ (29 W/m.K at 20 °C from Industeel, 34.5 W/m.K from Abrams); the 400 mm value is a section-size statement, not a measured depth.' story: recipe: line: An iron-based low-sulphur tool steel with chromium, molybdenum and about 1 percent nickel. Oberste-Beulmann lists the melt route as electric arc furnace melting with vacuum oxygen decarburisation (EAF + VOD). Industeel gives the minimum and maximum limits used below, and Abrams prints the same ranges. parts: - name: Iron symbol: Fe share_note: balance (the rest) role: Matrix of the steel; quenching and tempering set its structure. - name: Carbon symbol: C share_percent: 0.35 share_high: 0.45 role: Sets the hardness the steel can reach on quenching. source: industeel-ds2738 where: CHEMICAL ANALYSIS, Mini and Max rows - name: Silicon symbol: Si share_percent: 0.2 share_high: 0.4 role: Deoxidiser in the melt. source: industeel-ds2738 where: CHEMICAL ANALYSIS, Mini and Max rows - name: Manganese symbol: Mn share_percent: 1.3 share_high: 1.6 role: Adds hardenability. source: industeel-ds2738 where: CHEMICAL ANALYSIS, Mini and Max rows - name: Chromium symbol: Cr share_percent: 1.8 share_high: 2.1 role: Adds hardness and wear resistance. Far below the 10.5 percent that makes a steel stainless (Abrams). source: industeel-ds2738 where: CHEMICAL ANALYSIS, Mini and Max rows - name: Molybdenum symbol: Mo share_percent: 0.15 share_high: 0.25 role: Adds hardenability and toughness. source: industeel-ds2738 where: CHEMICAL ANALYSIS, Mini and Max rows - name: Nickel symbol: Ni share_percent: 0.9 share_high: 1.2 role: Improves through-hardening in large sections (Dörrenberg; Abrams). source: industeel-ds2738 where: CHEMICAL ANALYSIS, Mini and Max rows - name: Phosphorus symbol: P share_percent: 0 share_high: 0.03 role: Impurity, held to a maximum. source: industeel-ds2738 where: CHEMICAL ANALYSIS, Mini and Max rows - name: Sulphur symbol: S share_percent: 0 share_high: 0.03 role: Impurity, held very low; the low sulphur content supports texturing and polishing (Industeel). source: industeel-ds2738 where: CHEMICAL ANALYSIS, Mini and Max rows risk_groups: - title: For people level: 1 verdict: No SDS for 1.2738 read; element data only lead: The hazard records found are PubChem entries for elemental nickel, chromium, manganese and molybdenum. No safety data sheet for the steel was read in this run. points: - label: Nickel line: PubChem lists elemental nickel as Danger, with H317 (99.9 percent of notifications), H351 (72.9 percent) and H372 (99.7 percent). - label: Chromium line: Half of 2404 company reports say elemental chromium does not meet GHS criteria; H317 (20.7 percent) and H334 (20.3 percent) are common codes. - label: Manganese line: PubChem lists H228 (flammable solid, 11.6 percent of notifications), H360 and H372 for elemental manganese. - label: Molybdenum line: PubChem lists H361 (29.5 percent of notifications) and H228 (30 percent) for elemental molybdenum. - title: In service level: 2 verdict: Rust is the main watch point lead: Abrams says the grade is not stainless, so corrosion protection matters in service. points: - label: Corrosion line: Abrams says 1.2738 has a certain degree of corrosion resistance, but to be completely corrosion resistant it needs at least 10.5 percent chromium. - label: Corrosive plastics line: Aços Formosa points PVC and corrosive plastics to stainless 1.2316, not to 1.2738. - label: Reheating line: The Abrams tempering chart gives 42 HRC at 500 °C, 39 HRC at 600 °C and 28 HRC at 700 °C. - title: Heat treatment and welding level: 1 verdict: Keep weld and reheat temperatures in check lead: Heat sets the strength; the reheat and weld limits matter most. points: - label: Welding line: Preheat 316 to 371 °C and do not exceed 566 °C (Abrams); pre- and postheating are needed for crack-free welds (Industeel). - label: Quench line: Oberste-Beulmann warns of enhanced stress corrosion cracking after oil or polymer hardening and says to interrupt the quench at about 300 to 400 °C. - label: Hydrogen line: Temper at 180 °C for about 4 hours after hard chrome plating to avoid hydrogen embrittlement (Industeel). why: 'The grade is nickel-added P20 in the P-20 family: Abrams and Dörrenberg print it as AISI P20+Ni, and Aços Formosa lists it as P-20 + Ni for large molds. Dörrenberg says it contains extra nickel and no added sulphur, which improves through-hardening in dimensions above 400 mm. It is supplied quenched and tempered, so mould blocks can be machined and used without a further heat treatment. It is not stainless and needs protection against rust.' uses: - where: Plastic moulds, mould frames and die-casting dies line: Dörrenberg calls them large plastic moulds highly stressed in the core. Abrams lists moulding frames, die casting moulds and dies. - where: Hydroforming and forging tools line: Oberste-Beulmann lists hydroforming tools and dies. Abrams also lists forging tools, metal extrusion tools and tube presses. - where: Injection-mould cores and cavities line: Industeel says the grade is for plastic injection mould cores and cavities, for thermoplastics such as PE, PP and PS. can_do: - label: Hardness line: 'Supplied quenched and tempered: 280 to 325 HB (Dörrenberg), 290 to 325 HB (Oberste-Beulmann) and 290 to 330 HB or 30 to 35 HRC (Industeel). Blocks can be machined without a further heat treatment (Abrams).' - label: Strength line: At about 300 HB, Industeel prints a typical yield strength of 826 MPa and tensile strength of 993 MPa. Abrams gives about 1100 MPa on delivery. - label: Stiffness line: Modulus of elasticity is 205 GPa (Industeel, typical; Abrams prints 205 kN/mm2). - label: Toughness line: Industeel prints a typical KCV impact energy of 25 J at 20 °C. No Charpy curve or fracture toughness value is printed. - label: Through-hardening line: The nickel improves through-hardening, and the datasheets recommend the grade for dimensions above 400 mm (Dörrenberg; Abrams; Oberste-Beulmann). - label: Polish and texture line: Good polishability and texturing, with the low sulphur content given as the reason (Industeel; Abrams). - label: Machining line: Good machinability; Industeel says carbide drilling and milling work well and that the cutting data of 1.2311 can be applied. - label: Plating and nitriding line: Suitable for hard chromium plating and nitriding (Industeel; Abrams). Abrams says nitriding also increases corrosion resistance. compare: 'In the P-20 family that Aços Formosa lists, 1.2311 is for small and medium moulds, 1.2312 adds sulphur for faster machining, and 1.2738 adds nickel for large moulds and thick-section blocks. Dörrenberg says 1.2738 has extra nickel and no added sulphur, and Oberste-Beulmann says it is better through-hardened than 1.2311. The compare rows use the printed values for this grade: yield strength, modulus and density. No value for 1.2311 or 1.2312 is used here.' compare_rows: - label: Strength benchmark: yield_strength - label: Stiffness benchmark: elastic_modulus - label: Density benchmark: density handling: - 'Buy it supplied quenched and tempered: Abrams says heat treatment is not normally required for the supplied condition.' - Preheat to 250 to 300 °C before use, as Oberste-Beulmann recommends. - Stress relieve at 500 to 550 °C and cool slowly in the furnace (Dörrenberg, Oberste-Beulmann, Abrams). - Weld with a preheat of 316 to 371 °C, do not let it fall below 316 °C, cool to 100 to 150 °C, then heat to 538 °C for one hour per 25 mm of weld depth, and do not exceed 566 °C (Abrams). - After hard chrome plating, temper at 180 °C for about 4 hours to avoid hydrogen embrittlement (Industeel; Abrams). - After EDM or grinding, remove the rehardened white layer (Industeel). - Take the safety data sheet for the actual bar before cutting, grinding or welding. None was read for 1.2738 in this run. good_for: - Large plastic mould blocks, cores and frames machined in the supplied condition (Dörrenberg, Oberste-Beulmann, Abrams). - Textured and polished mould faces, where the low sulphur content helps (Industeel; Oberste-Beulmann). - Hydroforming tools and dies (Dörrenberg, Oberste-Beulmann, Abrams). watch_out: - 'Corrosion: the steel is not stainless, with 1.8 to 2.1 percent chromium (Abrams), so it has only a certain degree of corrosion resistance. Keep it protected in humid storage and service.' - Oil or polymer quenching can cause enhanced stress corrosion cracking; Oberste-Beulmann says to interrupt the quench at about 300 to 400 °C. - 'Reheat: tempering at 600 °C gives 39 HRC and at 700 °C gives 28 HRC (Abrams tempering chart), so a reheat to those temperatures softens the block.' - Welding above 566 °C loses hardness (Abrams). - 'Corrosive plastics: Aços Formosa points PVC and corrosive plastics to the stainless grade 1.2316 instead.' - 'Section size: Industeel calls 1.2738 a medium-size mould steel, while Dörrenberg, Oberste-Beulmann and Abrams point to large moulds and sections above 400 mm.' verdict: 1.2738 is a nickel-added, low-sulphur plastic mould steel, supplied quenched and tempered at about 280 to 330 HB. It machines and polishes well, and the nickel gives better through-hardening in large sections. It is not stainless, so keep it protected in humid storage and service, keep welding and reheat temperatures within the datasheet limits, and read the safety data sheet for the actual bar.