spore: profile id: tool-steel-p20 spore_version: 0.2 family: tool-steels name: P20 plastic mould steel (AISI P20, UNS T51620, EN 1.2311) abbreviation: P20 (UNS T51620) role: plastic mould steel category: metals type: steels-and-stainless summary: P20 is a pre-hardened chromium-molybdenum mould steel (UNS T51620; EN 1.2311) supplied at about 280 to 325 HB, so mould blocks can be machined and used without a further heat treatment. It machines and polishes well and is used for plastic moulds, mould frames and zinc die-casting dies. It is not corrosion resistant and rusts unless it is protected. best_for: Plastic injection-mould blocks, mould frames and bolsters that are machined in the pre-hardened condition and then polished (Smith Metal Centres; Oberste-Beulmann; Abrams). weakest_at: Corrosion resistance. The datasheets say it is not corrosion resistant and rusts unless protected; Aços Formosa points PVC and gas-releasing plastics to the stainless grade 1.2316 instead. identity: formula: Fe balance; 0.28 to 0.40 C, 0.60 to 1.00 Mn, 0.20 to 0.80 Si, 1.40 to 2.00 Cr, 0.30 to 0.55 Mo, 0.25 max Cu, 0.03 max P, 0.03 max S (wt%, P20 limits as printed by Smith Metal Centres). The EN grade 1.2311 (40CrMnMo7) prints 0.35 to 0.45 C, 0.2 to 0.4 Si, 1.3 to 1.6 Mn, 1.8 to 2.1 Cr and 0.15 to 0.25 Mo (Abrams). source: smith-p20 where: Chemical Composition (weight %), Min and Max rows designations: - system: AISI / SAE code: P20 source: smith-p20 where: Title block, P20 (T51620) - system: AISI code: P-20 source: alro-p20 where: Heading AISI P-20 Steel - system: Trade name code: P-20 source: formosa-p20 where: Plastic Molds, P-20 family - system: UNS code: T51620 source: tm-p20 where: Page heading and chemical composition table - system: ASTM code: A 681 Type P20 source: tm-p20 where: International Equivalent Materials table, row A 681 Type P20 (listed as Official) - system: EN code: '1.2311' source: beul-2311 where: Header, grade 1.2311+QT - system: EN name code: 40CrMnMo7 source: sij-2311 where: Designation by Standards table, DIN column - system: ISO code: '4957' source: doer-2738 where: Opening paragraph, listing 1.2311 (AISI P20) under DIN EN ISO 4957 - system: AFNOR code: 35CMD7 source: beul-2311 where: Standards column, AFNOR row - system: AFNOR code: 40CMD8 note: Oberste-Beulmann prints 35CMD7 for the same EN grade source: swiss-2311 where: Header, AISI P20 / AFNOR 40CMD8 - system: GOST code: 40ХГМА source: beul-2311 where: Standards column, GOST row - system: Trade name code: SIMOLD 2311 source: sij-2311 where: Header, SIMOLD 2311 Steel - system: Trade name code: PREMIUM 1.2311 source: abrams-12311 where: Page title, PREMIUM 1.2311 Steel - system: Trade name code: THYROPLAST 2311 source: tm-p20 where: International Equivalent Materials table, proprietary row (listed as Official) tags: environments: [] stresses: [] applications: - mechanisms - structures properties: - benchmark: density label: Density, average value value: 7.83 unit: g/cm3 scope: material conditions: condition: pre-hardened plastic mould steel, average value as printed temperature: ambient, as printed heat_treatment: not stated for density method: Physical properties table, average values at ambient temperature, as printed status: ground source: sij-2311 where: Physical properties, Density (g/cm3), 7.83 - benchmark: density label: Density, specific gravity value: 7.86 unit: g/cm3 scope: material conditions: temperature: not stated heat_treatment: not stated unit_in_source: kg/m3 (7861 kg/m3 printed beside 0.284 lb/in3) method: Properties block as printed (Specific Gravity 7.86) status: ground source: alro-p20 where: Properties block, Density and Specific Gravity rows - benchmark: elastic_modulus label: Modulus of elasticity, average value value: 210 unit: GPa scope: material conditions: condition: average value at ambient temperature, as printed heat_treatment: not stated unit_in_source: 10^3 x N/mm2 (equal to GPa) method: Physical properties table as printed; the datasheet says its values are typical or average, not guaranteed status: ground source: sij-2311 where: Physical properties, Modulus of elasticity, row 210 - benchmark: elastic_modulus label: Elastic modulus, typical value: 190 value_high: 210 bound: range unit: GPa scope: material conditions: condition: pre-hardened P20, typical values (about 300 HB, 30 HRC as printed) method: Mechanical properties (typical) table as printed status: ground source: smith-p20 where: Mechanical Properties (typical) table, Elastic Modulus column - benchmark: elastic_modulus label: Modulus of elasticity, 0 to 30 C value: 190 value_high: 210 bound: range unit: GPa scope: material conditions: temperature: 0 to 30 C (as printed) heat_treatment: not stated method: UNS T51620 physical properties table, range as printed status: ground source: tm-p20 where: UNS T51620 Physical Properties, Modulus of Elasticity row - benchmark: elastic_modulus label: Modulus of elasticity, typical value: 207 unit: GPa scope: material conditions: temperature: not stated heat_treatment: not stated unit_in_source: 30 x 10^6 psi (printed with 207 GPa) method: Properties block as printed status: ground source: alro-p20 where: Properties block, Modulus of Elasticity row - benchmark: poissons_ratio label: Poisson's ratio, 0 to 30 C value: 0.27 value_high: 0.3 bound: range unit: '-' scope: material conditions: temperature: 0 to 30 C (as printed) heat_treatment: not stated method: UNS T51620 physical properties table, range as printed status: ground source: tm-p20 where: UNS T51620 Physical Properties, Poisson Coefficient row - benchmark: yield_strength label: Yield strength, typical value: 827 value_high: 862 bound: range unit: MPa scope: material conditions: condition: pre-hardened P20, typical (about 300 HB, 30 HRC as printed) test: tensile, method not stated on the datasheet method: Mechanical properties (typical) table as printed, Yield column status: ground source: smith-p20 where: Mechanical Properties (typical) table, Tensile Strength Yield row - benchmark: ultimate_tensile_strength label: Tensile strength, typical value: 965 value_high: 1030 bound: range unit: MPa scope: material conditions: condition: pre-hardened P20, typical (about 300 HB, 30 HRC as printed) test: tensile, method not stated on the datasheet method: Mechanical properties (typical) table as printed, Ultimate column status: ground source: smith-p20 where: Mechanical Properties (typical) table, Tensile Strength Ultimate row - benchmark: ultimate_tensile_strength label: Tensile strength, converted from hardness value: 950 value_high: 1100 bound: range unit: MPa scope: material conditions: condition: supplied quenched and tempered, 280 to 325 HB as delivered unit_in_source: N/mm2 method: Converted from hardness by the datasheet (DIN EN ISO 18265 Tab. A.1), not a tensile test; kept as calculated status: calculated source: beul-2311 where: Header table, Tensile strength (N/mm2), 950 - 1100 - benchmark: elongation label: Elongation at break, typical value: 20 unit: '%' scope: material conditions: condition: pre-hardened P20, typical (about 300 HB, 30 HRC as printed) gauge: 50 mm (2 in.) as printed method: Mechanical properties (typical) table as printed status: ground source: smith-p20 where: Mechanical Properties (typical) table, Elongation at break in 50 mm row - benchmark: hardness_brinell label: Hardness as delivered value: 280 value_high: 325 bound: range unit: HB scope: material conditions: condition: supplied quenched and tempered (pre-hardened, as delivered) scale: HB method: Header table, Hardness (HB) row, as printed status: ground source: beul-2311 where: Header table, Hardness (HB) row, 280 - 325 - benchmark: hardness_brinell label: Hardness as delivered value: 280 value_high: 325 bound: range unit: HB scope: material conditions: condition: as-delivered pre-hardened condition scale: HB method: Material Properties list as printed, hardness in as-delivered condition status: ground source: swiss-2311 where: Material Properties, Hardness in as-delivered condition 280 to 325 HB - benchmark: hardness_brinell label: Hardness, typical value: 300 unit: HB scope: material conditions: condition: pre-hardened P20, typical values scale: HB method: Mechanical properties (typical) table as printed, Brinell column status: ground source: smith-p20 where: Mechanical Properties (typical) table, Hardness Brinell 300 - benchmark: hardness_brinell label: Hardness after soft annealing, maximum value: 230 bound: upper unit: HB scope: material conditions: condition: soft annealed at 710 to 740 C, cooled slowly in the furnace scale: HB method: Soft Annealing paragraph as printed (maximum Brinell hardness of 230) status: ground source: sij-2311 where: Soft Annealing paragraph - benchmark: hardness_rockwell_c label: Hardness, typical value: 30 unit: HRC scope: material conditions: condition: pre-hardened P20, typical values (about 300 HB as printed) scale: HRC method: Mechanical properties (typical) table as printed, Rockwell column status: ground source: smith-p20 where: Mechanical Properties (typical) table, Hardness Rockwell 30 - benchmark: hardness_rockwell_c label: Hardness, prehardened supply value: 30 value_high: 34 bound: range unit: HRC scope: material conditions: condition: prehardened, supplied condition for the P-20 family (approximately, as printed) scale: HRC method: Products and Applications text as printed, approximately 30 to 34 HRC status: ground source: formosa-p20 where: Introduction paragraph and P-20 Standard row (Prehardened 30-34 HRC) - benchmark: hardness_rockwell_c label: Hardness, pre-hardened (vendor statement) value: 28 value_high: 34 bound: range unit: HRC scope: material conditions: condition: pre-hardened, as supplied (vendor statement, no test conditions) scale: HRC method: Vendor comparison page, In-depth Analysis paragraph, as printed; a vendor statement, not a datasheet value status: ground note: vendor statement; the datasheets read give 30 to 34 HRC or 280 to 325 HB source: boxu-s136 where: In-depth Analysis paragraph, first sentence on P20 - benchmark: hardness_rockwell_c label: Working hardness, delivery condition value: 32 unit: HRC scope: material conditions: condition: delivery condition (pre-hardened) scale: HRC method: Standard values table as printed, approx. 32 HRC in the delivery condition status: ground source: abrams-12311 where: Standard values table, Working hardness row - benchmark: hardness_rockwell_c label: Hardness after quenching value: 51 unit: HRC scope: material conditions: condition: after hardening at 840 to 870 C with oil or salt-bath quench at 180 to 220 C (re-hardened, not the supplied condition) scale: HRC method: Heat treatment table, Hardening row, as printed (51 HRC after quenching) status: ground source: swiss-2311 where: Heat treatment table, Hardening row - 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) scale: HRC method: Tempering chart as printed status: ground source: swiss-2311 where: Heat treatment, Tempering chart, 500 C row - benchmark: hardness_rockwell_c label: Hardness after tempering at 600 C value: 36 unit: HRC scope: material conditions: condition: after hardening, tempered at 600 C (tempering chart; hold time not printed) scale: HRC method: Tempering chart as printed status: ground source: swiss-2311 where: Heat treatment, Tempering chart, 600 C row - 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) scale: HRC method: Tempering chart as printed status: ground source: swiss-2311 where: Heat treatment, Tempering chart, 700 C row - benchmark: thermal_conductivity label: Thermal conductivity, quenched and tempered value: 32.5 unit: W/m.K scope: material conditions: condition: quenched and tempered temperature: 23 C method: Physical properties table, Thermal conductivity, quenched and tempered column, as printed status: ground source: swiss-2311 where: Physical properties, Thermal conductivity (W/m.K), quenched and tempered, 23 C - benchmark: thermal_conductivity label: Thermal conductivity, quenched and tempered value: 34 unit: W/m.K scope: material conditions: condition: quenched and tempered temperature: 100 C method: Physical properties paragraph as printed, average values status: ground source: sij-2311 where: Physical properties, Thermal conductivity, 34.0 at 100 C, quenched and tempered - benchmark: cte label: Coefficient of thermal expansion, 20 to 100 C value: 12.6 unit: ppm/K scope: material conditions: condition: quenched and tempered temperature: 20 to 100 C unit_in_source: 10^-6 K^-1 (same number as ppm/K) method: Physical properties table, coefficient of thermal expansion row, as printed status: ground source: swiss-2311 where: Physical properties, coefficient of thermal expansion, 20 to 100 C, quenched and tempered - benchmark: cte label: Coefficient of thermal expansion, 20 to 500 C value: 14.3 unit: ppm/K scope: material conditions: condition: quenched and tempered temperature: 20 to 500 C unit_in_source: 10^-6 K^-1 (same number as ppm/K) method: Physical properties table, coefficient of thermal expansion row, as printed status: ground source: swiss-2311 where: Physical properties, coefficient of thermal expansion, 20 to 500 C, quenched and tempered - benchmark: cte label: Coefficient of thermal expansion, 20 to 100 C value: 11.7 unit: ppm/K scope: material conditions: temperature: 20 to 100 C heat_treatment: not stated unit_in_source: 10^-6 C^-1 (same number as ppm/K) method: Physical properties table as printed, average values at ambient temperature status: ground source: sij-2311 where: Physical properties, coefficient of thermal expansion, 20-100 C row - benchmark: machinability_relative label: Machinability relative to a 1% carbon steel value: 60 value_high: 65 bound: range unit: '%' scope: material conditions: reference: 1% carbon steel, as printed heat_treatment: not stated method: Properties block, Machinability row, as printed status: ground source: alro-p20 where: Properties block, Machinability row, 60-65% of a 1% carbon steel - benchmark: machinability_relative label: Machinability relative to W-group water-hardening steel value: 80 unit: '%' scope: material conditions: reference: W group water-hardening steels, as printed basis: printed as about 80% method: Machinability paragraph as printed status: ground note: approximate, printed as about 80% source: sij-2311 where: Machinability paragraph corrosion: - environment: Humid or wet storage, or service with no surface protection headline: The datasheet says the alloy will corrode or rust unless protected. effect: 'Simold 2311 states: ''This is a steel alloy and it will corrode or rust unless protected.'' No exposure time, humidity or test is given. The low rating is an assistant judgement from this wording, not a test result.' rating: low conditions: basis: datasheet statement test: none printed source: sij-2311 where: Corrosion Resistance paragraph - environment: Storage and use in damp or wet conditions (EN 1.2311) headline: Abrams says 1.2311 is not a corrosion resistant steel. effect: Abrams says 1.2311 is not a corrosion resistant steel and that surface treatment, maintenance and dry storage of parts can extend corrosion resistance but cannot completely prevent rusting. Bluing gives a black oxide layer with some corrosion protection, though it is usually done for appearance. The low rating is an assistant judgement from this wording. rating: low conditions: basis: datasheet statement for the EN grade test: none printed source: abrams-12311 where: Is the 1.2311 corrosion resistant? answer; Black oxide coating or blueing section - environment: Humid conditions with no protection (vendor comparison) headline: A vendor says P20 has no corrosion resistance. effect: The Boxumold comparison says P20 has no corrosion resistance and rusts in humid conditions without protection. It is a vendor statement with no test conditions. The low rating is an assistant judgement. rating: low conditions: basis: vendor statement test: none printed source: boxu-s136 where: Side-by-Side Comparison table, Corrosion Resistance row - environment: PVC and plastics that release aggressive gases during moulding headline: Aços Formosa points these plastics to stainless grades, not to P20. effect: Aços Formosa points PVC and gas-releasing plastics to 420-series stainless steels and to the prehardened stainless grade 1.2316, not to P20. It gives no corrosion test for P20 itself. rating: unknown conditions: basis: supplier product guidance test: none printed for P20 source: formosa-p20 where: Best Choice for Stainless Steels for Molds list and Applications list risks: hazards: - text: PubChem's aggregated GHS record for elemental chromium carries the signal word Danger. 50% of 2404 company reports (1202) say it does not meet GHS criteria. Reported codes include H317, may cause an allergic skin reaction (20.7% of reports), and H400, very toxic to aquatic life. The record describes the element, not the steel. ghs: - H317 - H400 source: pubchem-cr where: Safety and Hazards, GHS Classification (CID 23976) - text: 'PubChem''s aggregated GHS record for elemental manganese: 46.1% (1429 of 3101) of reports say it does not meet GHS criteria. Reported codes include H228, flammable solid (11.6% of reports), H360, may damage fertility or the unborn child, and H372, damage to organs through prolonged or repeated exposure. The record describes the element, not the steel.' ghs: - H228 - H360 - H372 source: pubchem-mn where: Safety and Hazards, GHS Classification (CID 23930) - text: 'PubChem''s aggregated GHS record for elemental molybdenum: 57.4% (874 of 1523) of reports say it does not meet GHS criteria. Reported codes include H225 (11.6% of reports), H315, skin irritation, and H335, may cause respiratory irritation. The record describes the element, not the steel.' ghs: - H225 - H315 - H335 source: pubchem-mo where: Safety and Hazards, GHS Classification (CID 23932) failure_risks: - mode: Softening when a weld or reheat goes above 565 C trigger: Weld repair or reheating above 565 C; the datasheet gives 540 C for weld tempering consequence: Hardness is lost if the material is heated above 565 C during welding (Abrams). severity: moderate source: abrams-12311 where: Welding section - mode: Softening on reheating to a higher temper trigger: Reheating or stress relief at 600 C or 700 C consequence: The Swiss Steel tempering chart gives 42 HRC after tempering at 500 C, 36 HRC at 600 C and 28 HRC at 700 C; a reheat above the supply temper softens the block. severity: moderate source: swiss-2311 where: Heat treatment, Tempering chart - mode: Stress corrosion cracking after oil hardening trigger: Oil hardening without interruption at 300 to 400 C, or cooling to room temperature before tempering consequence: The datasheet warns of enhanced stress corrosion cracking susceptibility after oil hardening, and says to temper while the part is at about 80 C. severity: moderate source: beul-2311 where: Heat treatment table, Quenching remarks - mode: Thick blocks harden less through trigger: Sections thicker than 400 mm consequence: The Oberste-Beulmann datasheet recommends 1.2738 for thicknesses above 400 mm because of its better through-hardenability. severity: moderate source: beul-2311 where: Header table, Remarks - mode: Rust in humid storage or service trigger: Storage or service in humid conditions without surface protection consequence: The steel rusts; the Simold datasheet says it will corrode or rust unless protected. severity: moderate source: sij-2311 where: Corrosion Resistance paragraph side_effects: [] handling: - text: Preheating before use at 200 to 300 C is recommended by the datasheet. source: beul-2311 where: Header table, Remarks (preheating before use) - text: Hot forming between 1050 and 850 C (as printed for forging). source: sij-2311 where: Forging paragraph - text: Soft anneal at 710 to 740 C in the furnace, cooling slowly; the Simold datasheet gives a maximum of 230 HB afterwards. source: sij-2311 where: Soft Annealing paragraph - text: Stress relieve at 500 to 550 C in the quenched and tempered condition, then cool in the furnace (Oberste-Beulmann). Abrams gives 550 to 600 C for 1 hour per 25 mm. source: beul-2311 where: Heat treatment table, Stress-relief annealing row - text: Stress relieve at 550 to 600 C for 1 hour per 25 mm of thickness, then cool in the furnace (Abrams). source: abrams-12311 where: 1.2311 Stress relieving section - text: Temper by holding at the tempering temperature for at least 1 hour per 25 mm of section, then cool in still air (Smith Metal Centres). source: smith-p20 where: Tempering paragraph - text: Re-harden from 830 to 880 C, then quench in oil or a warm bath at 180 to 220 C; the hardness after quenching is 51 HRC (Simold). source: sij-2311 where: Hardening paragraph - text: Weld with a preheat of 315 to 370 C, do not let the temperature fall below 315 C, cool slowly to 40 to 65 C, reheat to 540 C for 1 hour per 25 mm of weld depth, and do not exceed 565 C (Abrams). source: abrams-12311 where: 1.2311 Welding section mitigations: - text: Surface treatment, maintenance and dry storage can extend corrosion resistance but cannot completely prevent rusting (Abrams). source: abrams-12311 where: Is the 1.2311 corrosion resistant? answer - text: Nitriding gives a hard, abrasion-resistant surface to a depth of 0.40 mm (Abrams); the surface can be made harder than the pre-hardened core. source: abrams-12311 where: 1.2311 Nitriding section, printed as 0,40 mm with a decimal comma - text: For thick blocks above 400 mm, the Oberste-Beulmann datasheet recommends 1.2738 for better through-hardening. source: beul-2311 where: Header table, Remarks - text: For PVC and plastics that release aggressive gases, Aços Formosa points to the prehardened stainless grade 1.2316. source: formosa-p20 where: Best Choice list, Stainless Steels for Molds uses: - application: mechanisms device: Plastic injection-mould cavities, cores and inserts example: Aços Formosa lists cavities and cores among the applications of its P-20 family plastic mould steels. source: formosa-p20 where: Applications list - application: structures device: Mould frames, bolsters and die holders example: Smith Metal Centres says P20 is commonly used to make large mould frames and bolsters; Alro lists die holders and bolsters. source: smith-p20 where: Opening paragraph and Typical applications line - application: mechanisms device: Zinc die-casting dies and pressure-casting dies example: Smith Metal Centres and Alro list zinc die-casting dies among typical uses, and Simold lists pressure casting dies. source: alro-p20 where: Typical Uses line - application: mechanisms device: Rails and shafts (secondary use of the EN 1.2311 grade) example: Abrams says the grade is mainly used for plastic moulds, die casts and tools but is also suitable for applications such as rails and shafts. source: abrams-12311 where: Introduction paragraph supply: - subject: Chromium abundance: World resources are greater than 12 billion tons of shipping-grade chromite, 95% of them in Kazakhstan and southern Africa. US net import reliance was 79% of apparent consumption in 2025e (USGS). 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, read from a fetch summary (the page returned 403 to curl) listed: true - list: EU critical raw materials list, fifth list 2023 (34 CRMs, European Commission page) listed: false recycling: Recycled chromium in stainless-steel scrap receipts was 21% of US apparent consumption in 2025. 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 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; South Africa accounts for an estimated 70% of world resources. US net import reliance was 100% of apparent consumption in each year from 2021 to 2025e (USGS). 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, read from a fetch summary (the page returned 403 to curl) listed: true - list: EU critical raw materials list, fifth list 2023 (34 CRMs, European Commission page) listed: true recycling: Manganese was recycled incidentally in ferrous and nonferrous scrap, but scrap recovery specifically for manganese was negligible; it is recovered with iron from steel slag (USGS). substitutes: - Manganese has no satisfactory substitute in its major applications (USGS 2026). source: usgs-mn-2026 where: Salient Statistics; World Mine Production and Reserves (manganese content, 2025e; shares calculated by Space Mushroom from printed tonnage over the 20,000 thousand t world total); World Resources; Substitutes; Recycling - subject: Molybdenum abundance: Identified resources are about 5.4 million tons in the United States and about 20 million tons in the rest of the world; world reserves were 17,000 thousand t (2025e). Molybdenum is used principally as an alloying agent in steels, cast irons and superalloys (USGS 2026). 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, read from a fetch summary (no molybdenum entry) listed: false - list: EU critical raw materials list, fifth list 2023 (34 CRMs, European Commission page) listed: false recycling: Molybdenum is recycled as a component of catalysts, ferrous scrap and superalloy scrap; recycled material may be as much as 30% of the apparent supply (USGS 2026). substitutes: - There is little substitution for molybdenum in steels and cast irons; potential substitutes in alloy steels include boron, chromium, niobium and vanadium (USGS 2026). source: usgs-mo-2026 where: Salient Statistics and Events, Trends and Issues (China export controls, February 2025); World Mine Production and Reserves (2025e; shares calculated by Space Mushroom over the 260,000 thousand t world total); Substitutes; Recycling media: [] documents: - title: 'Smith Metal Centres: P20 (T51620) product datasheet' type: datasheet url: https://www.smithmetal.com/pdf/tool-steel/p20.pdf year: 2023 - title: 'Wilhelm Oberste-Beulmann: 1.2311+QT (40CrMnMo7) technical data sheet' type: datasheet url: https://www.oberste-beulmann.de/Dateien/Datenblaetter/1.2311.qt.en.pdf year: 2018 - title: 'Swiss Steel Group: Formadur 2311 pre-hardened plastic mould steel data sheet, rev. 2' type: datasheet url: https://swisssteel-group.com/content-media/documents/_import/20260428_SSG_DataSheets_Formadur2311_en_02.pdf year: 2026 - title: 'SIJ Metal Ravne: SIMOLD 2311 (1.2311) datasheet' type: datasheet url: https://cms.sij.si/storage/190/SIMOLD-2311_Metal.pdf year: 2016 - title: 'Abrams Industries: PREMIUM 1.2311 steel, standard values' type: datasheet url: https://eu.abrams-industries.com/steel/premium-12311 - title: 'Alro Steel: P-20 tool steel grade information' type: datasheet url: https://www.myalro.com/gradeinfo/Metals_Gridpt.aspx?gp=0335 - title: 'Aços Formosa: Plastic mold steels (P-20 family)' type: datasheet url: https://acosformosa.com.br/en/products/plastic-mold-steels/ year: 2026 - title: 'TotalMateria: UNS T51620 (P20) material page' type: database url: https://www.totalmateria.com/en-us/material/1241786 - title: 'Taizhou Boxumold: P20 vs S136 mold steel comparison (vendor article)' type: report url: https://www.boxumold.com/en/comparisons/p20-vs-s136-mold-steel year: 2026 - title: 'Dörrenberg: 1.2738 (P20+Ni) datasheet' type: datasheet url: https://doerrenberg.de/fileadmin/special_steel/files/pdf_en_products_neues_Design/1.2738_en.pdf - title: 'Industeel (ArcelorMittal): DS Mold 2738 (1.2738) datasheet' type: datasheet url: https://industeel.arcelormittal.com/fichier/ds-mold-2738 - 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: 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 - 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 year: 2026 - 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 year: 2026 - 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 year: 2026 gaps: - No safety data sheet for P20 steel was read in this run. The hazard entries are PubChem records for the pure elements chromium, manganese and molybdenum, which do not describe the steel. - 'Hardness as delivered is printed differently by each source: 280 to 325 HB (Oberste-Beulmann, Swiss Steel), about 300 HB and 30 HRC typical (Smith Metal Centres), 30 to 34 HRC (Aços Formosa), about 32 HRC (Abrams) and 28 to 34 HRC (Boxumold, a vendor). None of the pages read in this run printed 28 to 32 HRC for P20 itself, so the about 28 to 32 HRC figure in the brief is not confirmed here.' - 'Composition: the P20 ranges (Smith Metal Centres, TotalMateria) and the EN 1.2311 ranges (Abrams) differ, and the typical values in the 1.2311 datasheets (Simold, Swiss Steel) differ again. The recipe uses the P20 ranges.' - 'Nickel: the Smith Metal Centres text says nickel and chromium enhance hardness and toughness, but its P20 composition table gives no nickel limit, and no P20 table read here lists one.' - 'Soft-annealed hardness conflicts: Simold prints a maximum of 230 HB after soft annealing at 710 to 740 C, while Swiss Steel prints 325 HB or less for the same treatment. Both are kept with their sources; the two were not reconciled.' - 'Stress-relief temperatures differ: 500 to 550 C for the quenched and tempered condition (Oberste-Beulmann), 550 to 600 C for 1 hour per 25 mm (Abrams), and about 650 C for 1 to 2 hours to remove machining stresses (Simold). The Oberste-Beulmann tempering chart gives 32 HRC at 650 C, so the 650 C figure would soften a pre-hardened block; this is an inference, not a printed statement.' - 'Temper hold times differ: at least 1 hour per 25 mm (Smith Metal Centres), at least 2 hours or 1 hour per 25 mm (Abrams), and 1 hour per 20 mm with a minimum of 2 hours (Oberste-Beulmann).' - No P20 corrosion test was found in any fetched source. The corrosion entries are datasheet statements and a vendor comparison; no salt, acid or humidity exposure data for P20 were read. A nitriding corrosion study on Impax Supreme (its Gamry abstract calls it equivalent to AISI P20) was fetched but not used, because it is a different steel. - 'Polishability is described in datasheets and vendor text, not measured: no surface roughness or finish data for P20 were read. The Boxumold SPI B-to-D statement is vendor text and is not used as a value.' - Hardness and machinability use snake_case benchmark names (hardness_brinell, hardness_rockwell_c, machinability_relative) because property-canon.yaml has no entry for them. - Critical-mineral status for the USGS 2025 list was read from a WebFetch summary of the USGS page, because curl returned 403 for that page; it is not raw text. The EU status was read from the European Commission page. - Supply shares are calculated by Space Mushroom from the printed USGS tonnage over the printed world totals; they are not printed percentages. - No space, vacuum, radiation or flight use of P20 was found in these sources. The uses are terrestrial moulds, dies and machinery parts. - No Charpy, fracture toughness or fatigue values for P20 were printed in the sources read; the Smith Metal Centres and Alro texts mention toughness without numbers. - No photograph or micrograph of P20 with a licence we could cite was fetched in this run, so media is empty. - 'Designations: the site''s identity schema has no designations field, so identity.designations is likely dropped on import until the schema has that field.' - 'Not reached in this run: ASM Alloy Digest (login required), MakeItFrom (blocked), VEM Tooling and suppliersonline (no readable text), BGH datasheet (blocked), PACE Metallographic (database offline, no P20 values), and the Meusburger 12311 page (navigation only). Dillinger DIMO 2311 is a modified variant and was not read.' sources: smith-p20: title: 'Smith Metal Centres: P20 (T51620) product datasheet' id: P20 (T51620) url: https://www.smithmetal.com/pdf/tool-steel/p20.pdf year: 2023 kind: datasheet license: supplier datasheet, cited not reproduced beul-2311: title: 'Wilhelm Oberste-Beulmann: 1.2311+QT (40CrMnMo7) technical data sheet' id: 1.2311+QT, code 40CrMnMo7 url: https://www.oberste-beulmann.de/Dateien/Datenblaetter/1.2311.qt.en.pdf year: 2018 kind: datasheet license: supplier datasheet, cited not reproduced swiss-2311: title: 'Swiss Steel Group: Formadur 2311 pre-hardened plastic mould steel data sheet, rev. 2' id: Formadur 2311, AISI P20 / AFNOR 40CMD8 url: https://swisssteel-group.com/content-media/documents/_import/20260428_SSG_DataSheets_Formadur2311_en_02.pdf year: 2026 kind: datasheet license: supplier datasheet, cited not reproduced sij-2311: title: 'SIJ Metal Ravne: SIMOLD 2311 (1.2311) datasheet' id: SIMOLD 2311, 1.2311, approx. P20 url: https://cms.sij.si/storage/190/SIMOLD-2311_Metal.pdf year: 2016 kind: datasheet license: supplier datasheet, cited not reproduced abrams-12311: title: 'Abrams Industries: PREMIUM 1.2311 steel, standard values (text derived from stahlwissen.de)' id: PREMIUM 1.2311 url: https://eu.abrams-industries.com/steel/premium-12311 kind: web license: supplier web page, cited not reproduced alro-p20: title: 'Alro Steel: P-20 tool steel grade information' id: AISI P-20 url: https://www.myalro.com/gradeinfo/Metals_Gridpt.aspx?gp=0335 kind: web license: supplier web page, cited not reproduced formosa-p20: title: 'Aços Formosa: Plastic mold steels (P-20 family, 1.2311, 1.2312, 1.2738, 1.2316)' id: P-20 family url: https://acosformosa.com.br/en/products/plastic-mold-steels/ year: 2026 kind: web license: supplier web page, cited not reproduced tm-p20: title: 'TotalMateria: UNS T51620 (P20) material page, chemical composition, physical properties and equivalents' id: UNS T51620 url: https://www.totalmateria.com/en-us/material/1241786 kind: database license: database page, cited not reproduced boxu-s136: title: 'Taizhou Boxumold: P20 vs S136 mold steel comparison (vendor article)' id: vendor comparison url: https://www.boxumold.com/en/comparisons/p20-vs-s136-mold-steel year: 2026 kind: web license: vendor page, cited not reproduced doer-2738: title: 'Dörrenberg: 1.2738 (P20+Ni) datasheet, opening paragraph on the DIN EN ISO 4957 grades' id: '1.2738' url: https://doerrenberg.de/fileadmin/special_steel/files/pdf_en_products_neues_Design/1.2738_en.pdf kind: datasheet license: supplier datasheet, cited not reproduced ind-2738: title: 'Industeel (ArcelorMittal): DS Mold 2738 (W 1.2738) datasheet' id: W 1.2738 url: https://industeel.arcelormittal.com/fichier/ds-mold-2738 kind: datasheet license: supplier datasheet, cited not reproduced 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-crit-2025: title: 'USGS: About the 2025 List of Critical Minerals' id: 2025 list (60 minerals) 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 pubchem-cr: 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 year: 2026 kind: database license: PubChem terms (public) pubchem-mn: 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 year: 2026 kind: database license: PubChem terms (public) pubchem-mo: 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 year: 2026 kind: database license: PubChem terms (public) license: CC-BY-4.0 updated: '2026-10-24' review: status: draft method: assistant checked_values: 30 unreachable: 0 caveats: 3 note: 'Read by an AI assistant on 2026-10-24 from pages fetched in this run. Caveats: the converted tensile value (calculated, not tested), the Boxumold hardness range (a vendor statement), and the about 80 percent machinability figure (approximate). The USGS 2025 critical-list page could not be read with curl (403); its status was read from a fetch summary. Blocked or empty: ASM Alloy Digest, MakeItFrom, VEM Tooling, suppliersonline, BGH and PACE.' story: recipe: line: P20 is an iron-based chromium-molybdenum tool steel with 0.28 to 0.40 percent carbon. The limits here are the P20 ranges printed by Smith Metal Centres. The EN grade 1.2311 has narrower manganese and chromium ranges (Abrams). Its strength comes from the pre-hardened heat treatment as much as from its composition. parts: - name: Iron symbol: Fe share_note: balance (the rest) role: The matrix of the steel. Heat treatment changes its structure between martensite and tempered martensite. - name: Carbon symbol: C share_percent: 0.28 share_high: 0.4 role: Sets how hard the steel can become when quenched. - name: Manganese symbol: Mn share_percent: 0.6 share_high: 1 role: Adds hardenability and helps the melt. - name: Silicon symbol: Si share_percent: 0.2 share_high: 0.8 role: Deoxidiser in the melt. - name: Chromium symbol: Cr share_percent: 1.4 share_high: 2 role: Adds hardness and toughness in the alloy (Smith Metal Centres). The grade is not stainless. - name: Molybdenum symbol: Mo share_percent: 0.3 share_high: 0.55 role: Adds hardenability. The grade still rusts unless protected. - name: Copper symbol: Cu share_percent: 0 share_high: 0.25 role: Upper limit as printed by Smith Metal Centres; no role is stated in the datasheet. - name: Phosphorus symbol: P share_percent: 0 share_high: 0.03 role: Impurity, held to a maximum. - name: Sulfur symbol: S share_percent: 0 share_high: 0.03 role: Impurity, held to a maximum. risk_groups: - title: For people level: 1 verdict: No SDS for P20 read; element data only lead: The only hazard records found are PubChem entries for the pure elements chromium, manganese and molybdenum. No safety data sheet for P20 bar was read in this run. points: - label: Chromium line: PubChem lists elemental chromium as Danger. Half of 2404 company reports say it does not meet GHS criteria; H317, allergic skin reaction, appears for 20.7% of reports. - label: Manganese line: PubChem lists elemental manganese with H228 (flammable solid, 11.6% of reports), H360 (may damage fertility or the unborn child) and H372 (organ damage on repeated exposure). - label: Molybdenum line: PubChem reports that 57.4% of its reports say elemental molybdenum does not meet GHS criteria; H315 (skin irritation) and H335 (respiratory irritation) appear among the codes. - title: In service level: 2 verdict: Rust is the main watch point lead: The datasheets say the steel is not corrosion resistant, so rust is the main in-service concern. points: - label: Rust line: The Simold datasheet says the alloy will corrode or rust unless protected. Abrams says surface treatment and dry storage extend resistance but cannot completely prevent rusting. - label: Corrosive plastics line: Aços Formosa points PVC and plastics that release aggressive gases to the stainless grade 1.2316, not to P20. - label: Reheating line: The Swiss Steel tempering chart shows hardness falling from 42 HRC after tempering at 500 C to 36 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, and the reheat limits matter most. points: - label: Welding line: Abrams gives a preheat of 315 to 370 C and a limit of 565 C on reheating; above that, hardness can be lost. - label: Stress relief line: Oberste-Beulmann gives 500 to 550 C for the quenched and tempered condition; Abrams gives 550 to 600 C. - label: Re-hardening line: Re-hardening from 830 to 880 C in oil or a warm bath at 180 to 220 C gives about 51 HRC (Simold). why: 'P20 (UNS T51620, EN 1.2311) is a chromium-molybdenum mould steel. It is bought pre-hardened at about 280 to 325 HB, so mould blocks can be cut and used without a further heat treatment. Its machinability and polishing are good, and it is used for plastic moulds, mould frames and zinc die-casting dies. Its weak point is corrosion resistance: the datasheets say it rusts unless protected.' uses: - where: Plastic moulds and frames line: Oberste-Beulmann and Swiss Steel list plastic moulds, mould frames and pressure-casting moulds. Smith Metal Centres calls P20 a common steel for large mould frames and bolsters. - where: Zinc die-casting dies line: Smith Metal Centres and Alro list zinc die-casting dies among the typical uses. - where: Rails and shafts line: Abrams also lists rails and shafts as suitable applications for the EN 1.2311 grade. can_do: - label: Hardness line: Supplied at 280 to 325 HB (Oberste-Beulmann and Swiss Steel), so blocks can be machined and used without a further heat treatment (Abrams). - label: Strength line: Typical yield strength is 827 to 862 MPa and tensile strength 965 to 1030 MPa in the pre-hardened condition (Smith Metal Centres, typical values). - label: Stiffness line: Modulus of elasticity is 190 to 210 GPa (Smith Metal Centres) and 210 GPa (Simold, average value). - label: Machining line: Machinability is 60 to 65 percent of a 1% carbon steel (Alro), or about 80 percent of W-group water-hardening steel (Simold). - label: Polish line: Polishes to a high gloss, but over-polishing can cause orange peel and pitting (Abrams). Oberste-Beulmann says it is better polishable than the 1.2312 grade. - label: Weld line: Can be welded by conventional methods with preheat and controlled cooling (Abrams). Smith Metal Centres says it has good weldability. - label: Nitride line: Can be nitrided to a case about 0.40 mm deep for a harder, wear-resistant surface (Abrams). compare: 'P20 sits in a family of pre-hardened plastic mould steels from Aços Formosa: 1.2311 for small and medium moulds, 1.2312 for high machinability, 1.2738 (nickel-added) for large moulds, and P-20 ESR for high-gloss work. For corrosive plastics, Aços Formosa points to the stainless prehardened grade 1.2316 instead. The compare rows give P20''s typical strength, stiffness and density.' compare_rows: - label: Strength benchmark: yield_strength - label: Stiffness benchmark: elastic_modulus - label: Density benchmark: density handling: - Buy and machine it pre-hardened; Abrams says heat treatment is not normally required for the supplied condition. - 'Keep reheats and welding inside the limits: loss of hardness is the risk above 565 C (Abrams).' - Protect it from rust with a surface treatment and dry storage; Abrams says these extend resistance but cannot completely prevent rusting. - Stress relieve at 500 to 550 C for the quenched and tempered condition, then cool in the furnace (Oberste-Beulmann). - Weld only with the preheat and controlled cool-down in the procedure (315 to 370 C preheat, Abrams). - Take a safety data sheet for the specific bar before cutting, grinding or welding; none was read for P20 in this run. good_for: - Plastic injection-mould blocks and frames machined in the pre-hardened condition (Smith Metal Centres; Oberste-Beulmann). - Zinc and pressure-casting dies, which the datasheets list as typical uses (Smith Metal Centres; Alro). - Textured and polished mould faces; the datasheets say the grade takes texture and polish well (Simold; Abrams). watch_out: - 'Rust: the steel rusts unless it is protected; surface treatment and dry storage extend resistance but cannot completely prevent rusting (Simold; Abrams).' - Heat above 565 C during welding or reheating can lose hardness (Abrams); tempering at 600 C leaves 36 HRC (Swiss Steel). - 'Thick blocks: above 400 mm the Oberste-Beulmann datasheet recommends 1.2738 for better through-hardening.' - 'Corrosive plastics: for PVC and gas-releasing plastics, Aços Formosa points to the stainless 1.2316 instead.' verdict: P20 is a practical, pre-hardened mould steel. It is supplied at about 280 to 325 HB, machines and polishes well, and suits plastic moulds, mould frames and zinc die-casting dies. It is not corrosion resistant, so protect it from rust, keep reheats within the datasheet limits, and use 1.2738 for thick blocks or a stainless grade for corrosive plastics.