Steel M4 · heat-treated state
Steel M4 Hardened & Tempered
Properties of the Hardened & Tempered condition, compared with the other M4 tempers.
General working hardness for cold-work punches, form tools and broaches — best wear/toughness balance.
What is M4 Hardened & Tempered?
M4 Hardened & Tempered is M4 heat treated to Hardened & Tempered — general working hardness for cold-work punches, form tools and broaches — best wear/toughness balance. M4 Hardened & Tempered has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 2,200 MPa (319 ksi) — stronger than 71% of steel grades. Elongation at break is 12% and the elastic modulus is 217 GPa (31.5 Msi). M4 Hardened & Tempered has a density of 7.97 g/cm³ (0.288 lb/in³), heavier than 94% of steel grades. It melts at 1,250°C (2,282 °F). Annealed is the default condition FabDigit quotes; Hardened & Tempered is available on request or by drawing note.
Advantages
- High service temperature — 560°C (1,040 °F), better than 96% of steel grades
Limitations
- Difficult to machine — 5/100, worse than 100% of steel grades
- Low fracture toughness — 17 MPa·√m (15.5 ksi·√in), worse than 99% of steel grades
- High embodied carbon — 4.2 kg CO₂/kg, worse than 94% of steel grades
- Poor heat conductor — 22 W/m·K (12.7 BTU/hr·ft·°F), worse than 93% of steel grades
- Low electrical conductivity — 2.9 % IACS, worse than 93% of steel grades
M4 Hardened & Tempered properties
Typical room-temperature values for M4 Hardened & Tempered — 12 properties are specific to this condition; the rest are grade-level values shared by every M4 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
M4 Hardened & Tempered has a density of 7.97 g/cm³ (0.288 lb/in³), heavier than 94% of steel grades. It melts at 1,250°C (2,282 °F).
Mechanical14
M4 Hardened & Tempered has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 2,200 MPa (319 ksi) — stronger than 71% of steel grades. Elongation at break is 12% and the elastic modulus is 217 GPa (31.5 Msi).
Thermal6
M4 Hardened & Tempered is rated for continuous service to 560°C (1,040 °F). It conducts heat at 22 W/m·K (12.7 BTU/hr·ft·°F), worse than 93% of steel grades. Thermal expansion is 11 µm/m·K (6.11 µin/in·°F).
Electrical3
M4 Hardened & Tempered conducts electricity at 2.9 % IACS, worse than 93% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (20/100), better than 87% of steel grades.
Sustainability4
Producing a kilogram of M4 Hardened & Tempered takes about 58 MJ of energy and emits 4.2 kg of CO₂ — more than 95% of steel grades. Typical recycled content is 35%.
Manufacturability8
M4 Hardened & Tempered's machinability is not recommended (5/100, worse than 100% of steel grades); weldability poor (15/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other M4 tempers and conditions
M4 is also supplied in 6 other conditions. The full side-by-side table is on the M4 overview.
- AnnealedDefaultStandard supply condition for bar and flats; machine tool blanks in this state, then harden.550 MPa yield · 24 HRC
- Hardened & TemperedGeneral working hardness for cold-work punches, form tools and broaches — best wear/toughness balance.2,200 MPa tensile
Working with M4 Hardened & Tempered
Is M4 easy to machine?
Machine only in the annealed state with rigid setups, low speeds and carbide or coated-carbide tooling; the 4% V carbides also make grinding difficult — use SG/CBN wheels and light passes.
Can M4 be welded?
Not a structural weld grade; repair-weld only with matched HSS filler, preheat 480–540 °C, weld hot and re-temper immediately to avoid cracking.
Can M4 be formed, bent or molded?
Hot forge 1000–1120 °C (stop above ~950 °C) and slow cool, then full spheroidize anneal at ~870 °C; no meaningful cold forming.
What surface finishes work on M4?
Finish grind after hardening, then nitride, black-oxide, steam-treat or PVD-coat (TiN/TiAlN) for wear and rust protection; oil or wax bare surfaces in storage.
M4 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 | 1.25 – 1.4 | 1.32 |
| Mn | 0.15 – 0.4 | 0.3 |
| Si | 0.2 – 0.45 | 0.3 |
| Cr | 3.75 – 4.75 | 4.25 |
| Vhigh V gives MC carbides / wear resistance | 3.75 – 4.5 | 4 |
| W | 5.25 – 6.5 | 5.75 |
| Mo | 4.25 – 5.5 | 4.75 |
| P | ≤ 0.03 | — |
| Smax; resulfurized M4 variants allow 0.06–0.15 | ≤ 0.03 | — |
| Fe | balance | — |
M4 Hardened & Tempered — frequently asked
What is M4 Hardened & Tempered used for?
M4 Hardened & Tempered is typically used for broaches, cutting tools and milling cutters. In short: high-impact toughness.
What is the yield strength of M4 Hardened & Tempered?
M4 Hardened & Tempered has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 2,200 MPa (319 ksi) — stronger than 71% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is M4 Hardened & Tempered easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 100% of steel grades). Machine only in the annealed state with rigid setups, low speeds and carbide or coated-carbide tooling; the 4% V carbides also make grinding difficult — use SG/CBN wheels and light passes.
Can M4 Hardened & Tempered be welded?
Not readily — weldability is rated poor (15/100). Not a structural weld grade; repair-weld only with matched HSS filler, preheat 480–540 °C, weld hot and re-temper immediately to avoid cracking.
What surface finishes work on M4 Hardened & Tempered?
Finish grind after hardening, then nitride, black-oxide, steam-treat or PVD-coat (TiN/TiAlN) for wear and rust protection; oil or wax bare surfaces in storage.
Can M4 Hardened & Tempered be formed, bent or molded?
Hot forge 1000–1120 °C (stop above ~950 °C) and slow cool, then full spheroidize anneal at ~870 °C; no meaningful cold forming.
What is the maximum service temperature of M4 Hardened & Tempered?
M4 Hardened & Tempered is rated for continuous use to about 560°C (1,040 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in M4 Hardened & Tempered?
Yes — M4 Hardened & Tempered is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A600 — Standard Specification for Tool Steel High Speed — ASTM International (2016)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Tool Steels, 5th Edition (Roberts, Krauss, Kennedy) — ASM International (1998)
- CPM M4 / M4 High Speed Steel data sheet — Crucible Industries (2020)
- High speed steel grade data (M4 / HS6-5-4) — Erasteel (2021)
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.