Steel 3Cr2Mo Annealed
Temper
GB 3Cr2Mo · AISI/SAE P20
Pick when the mould will be through-hardened after roughing, or for maximum machinability.
Values for the Annealed condition
Other 3Cr2Mo tempers and conditions
3Cr2Mo is listed in 8 conditions; see the grade overview at 3Cr2Mo.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedThis page soft annealed for deep machining/EDM before hardening | Pick when the mould will be through-hardened after roughing, or for maximum machinability. | 450 | 700 | 22 | 210 HB | — |
air cooled from austenitizing, intermediate strength | Used for bar stock and for grain refinement before final quench and temper. | 570 | 860 | 18 | 24 HRC | 8 % IACS |
PH 28-32 HRCDefault Pre-hardened 28–32 HRC | Default stock condition: machine the cavity directly, no further heat treatment or distortion risk. | 830 | 1,000 | 15 | 30 HRC | — |
Pre-hardened then gas/plasma nitrided surface | Pick for abrasive glass-filled resins: hard nitrided case on a 30 HRC tough core, minimal distortion. | 830 | 1,000 | 13 | 30 HRC | 8 % IACS |
Electroslag-remelted, pre-hardened 28–32 HRC | Choose when optical or high-gloss polish and low inclusion content are required in large cavities. | 850 | 1,020 | 17 | 30 HRC | 8 % IACS |
Pre-hardened 33–38 HRC | Choose for higher wear resistance and better texture/polish on large moulds where machining power allows. | 1,000 | 1,180 | 13 | 36 HRC | — |
Quenched and tempered to 40–44 HRC | For inserts and small cores needing extra wear resistance; machine soft, then harden and finish-grind/EDM. | 1,150 | 1,350 | 11 | 42 HRC | — |
Quenched and low-tempered to 48–52 HRC | Maximum attainable hardness for small sections; toughness and machinability drop sharply, EDM/grinding only. | 1,450 | 1,700 | 8 | 50 HRC | — |
What is 3Cr2Mo Annealed?
3Cr2Mo Annealed is 3Cr2Mo in the Annealed temper — pick when the mould will be through-hardened after roughing, or for maximum machinability. 3Cr2Mo Annealed has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 52% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi). 3Cr2Mo Annealed has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). PH 28-32 HRC is the default condition FabDigit quotes; Annealed is available on request or by drawing note.
Advantages
- Easy to machine — 68/100, better than 95% of steel grades
Limitations
- Limited formability — 15/100, worse than 87% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
- Poor heat conductor — 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 82% of steel grades
3Cr2Mo Annealed properties
Typical room-temperature values for 3Cr2Mo Annealed; 11 are specific to this condition. Other listed values are 3Cr2Mo reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
3Cr2Mo Annealed has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
3Cr2Mo Annealed has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 52% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
3Cr2Mo Annealed is rated for continuous service to 400°C (752 °F). It conducts heat at 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 82% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
3Cr2Mo Annealed conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (14/100), better than 70% of steel grades.
Sustainability4
Producing a kilogram of 3Cr2Mo Annealed takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 35%.
Manufacturability6
3Cr2Mo Annealed's machinability is good (68/100, better than 95% of steel grades); weldability fair (50/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 3Cr2Mo Annealed
Is 3Cr2Mo easy to machine?
Cuts well at 28–32 HRC with coated carbide (roughing ~120–180 m/min); use rigid setups and avoid dwell to prevent work-hardened glazing, EDM finishing is routine.
Can 3Cr2Mo be welded?
Weldable for mould repair with matching low-alloy or 420-type filler at 200–300 °C preheat plus post-weld temper 20–30 °C below the original tempering temperature.
Can 3Cr2Mo be formed, bent or molded?
Not a cold-forming steel; hot forge 1050–850 °C followed by slow cool and annealing, then quench from 850–880 °C in oil and temper 550–650 °C for the pre-hardened level.
What surface finishes work on 3Cr2Mo?
Takes a good but not mirror polish (ESR quality is better), responds well to photo-etch texturing, and is commonly hard-chrome or nickel plated for corrosive resins and gloss surfaces.
3Cr2Mo chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | 0.28 – 0.4 | 0.35 |
| Si | 0.2 – 0.8 | 0.4 |
| Mn | 0.6 – 1 | 0.8 |
| Cr | 1.4 – 2 | 1.7 |
| Mo | 0.3 – 0.55 | 0.45 |
| P | ≤ 0.03 | — |
| Smax; free-machining variants (3Cr2MnNiMo/718S) add S ~0.05-0.10 | ≤ 0.03 | — |
| Fe | balance | — |
3Cr2Mo Annealed — frequently asked
What is 3Cr2Mo Annealed used for?
3Cr2Mo Annealed is typically used for injection mold cavities, mold bases and die-casting dies. In short: industry-standard mold block steel; pre-hardened, no heat treatment; cheaper than stainless mold steels.
What is the yield strength of 3Cr2Mo Annealed?
3Cr2Mo Annealed has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 52% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 3Cr2Mo Annealed easy to machine?
Reasonably — machinability is rated good (68/100, better than 95% of steel grades). Cuts well at 28–32 HRC with coated carbide (roughing ~120–180 m/min); use rigid setups and avoid dwell to prevent work-hardened glazing, EDM finishing is routine.
Can 3Cr2Mo Annealed be welded?
With care — weldability is rated fair (50/100). Weldable for mould repair with matching low-alloy or 420-type filler at 200–300 °C preheat plus post-weld temper 20–30 °C below the original tempering temperature.
What surface finishes work on 3Cr2Mo Annealed?
Takes a good but not mirror polish (ESR quality is better), responds well to photo-etch texturing, and is commonly hard-chrome or nickel plated for corrosive resins and gloss surfaces.
Can 3Cr2Mo Annealed be formed, bent or molded?
Not a cold-forming steel; hot forge 1050–850 °C followed by slow cool and annealing, then quench from 850–880 °C in oil and temper 550–650 °C for the pre-hardened level.
What is the maximum service temperature of 3Cr2Mo Annealed?
3Cr2Mo Annealed is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM A681 Standard Specification for Tool Steels Alloy (P20) — ASTM (2022)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Specialty Handbook — Tool Materials — ASM International (1995)
- Pre-hardened plastic mould steel (P20/718 class) datasheet — Uddeholm / ASSAB (2021)
- P20/3Cr2Mo — Mysteel / 1688 (2025)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.