Steel M4 · temper · default condition
Steel M4 Annealed
Properties of the Annealed condition, compared with the other M4 tempers.
Standard supply condition for bar and flats; machine tool blanks in this state, then harden.
What is M4 Annealed?
M4 Annealed is M4 in the Annealed temper — standard supply condition for bar and flats; machine tool blanks in this state, then harden. M4 Annealed has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 71% of steel grades. Elongation at break is 12% and the elastic modulus is 217 GPa (31.5 Msi). M4 Annealed 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).
Limitations
- Low fracture toughness — 22 MPa·√m (20 ksi·√in), worse than 98% 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
- Difficult to machine — 25/100, worse than 93% of steel grades
M4 Annealed properties
Typical room-temperature values for M4 Annealed — 11 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 Annealed 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 Annealed has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 71% of steel grades. Elongation at break is 12% and the elastic modulus is 217 GPa (31.5 Msi).
Thermal6
M4 Annealed is rated for continuous service to 400°C (752 °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 Annealed conducts electricity at 2.9 % IACS, worse than 93% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (18/100), better than 83% of steel grades.
Sustainability4
Producing a kilogram of M4 Annealed 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 Annealed's machinability is poor (25/100, worse than 93% of steel grades); weldability poor (15/100); formability not recommended (12/100).
Common Calculations5
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 Annealed
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 Annealed — frequently asked
What is M4 Annealed used for?
M4 Annealed is typically used for broaches, cutting tools and milling cutters. In short: high-impact toughness.
What is the yield strength of M4 Annealed?
M4 Annealed has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 71% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is M4 Annealed easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% 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 Annealed 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 Annealed?
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 Annealed 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 Annealed?
M4 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.
Can FabDigit make parts in M4 Annealed?
Yes — M4 Annealed 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.