Steel M4 Stress Relieved
Heat-treated state
AISI/SAE M4 · UNS T11304 · EN S6-5-4 · JIS SKH54 · GB W6Mo5Cr4V4
Intermediate step for large or asymmetric tools to minimise distortion during hardening.
Values for the Stress Relieved condition
Other M4 tempers and conditions
M4 is listed in 6 conditions; see the grade overview at M4.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault spheroidize annealed, 223–255 HB | Standard supply condition for bar and flats; machine tool blanks in this state, then harden. | 550 | 880 | 12 | 24 HRC | — |
Stress RelievedThis page Stress relieved after rough machining (~650–700 °C, annealed base) | Intermediate step for large or asymmetric tools to minimise distortion during hardening. | 560 | 890 | 11 | 25 HRC | 2.9 % IACS |
Hardened & Tempered 60–62 HRC | Choose when impact/chipping dominates over abrasive wear, e.g. heavy blanking and trim dies. | 1,900 | 2,150 | 2 | 61 HRC | 2.7 % IACS |
deep freeze (−80 to −196 °C) between tempers | Adds ~0.5–1 HRC and improves dimensional stability by converting retained austenite; used for precision gauges and long-run punches. | 2,000 | 2,300 | 1 | 64 HRC | 2.7 % IACS |
Hardened & Tempered 64–66 HRC | Maximum wear resistance and red hardness for cutting tools; accept lower toughness and chipping risk. | 2,050 | 2,350 | 1 | 65 HRC | 2.6 % IACS |
62–64 HRC (austenitize ~1200 °C, triple temper ~550 °C) | General working hardness for cold-work punches, form tools and broaches — best wear/toughness balance. | — | 2,200 | — | 63 HRC | — |
What is M4 Stress Relieved?
M4 Stress Relieved is M4 heat treated to Stress Relieved — intermediate step for large or asymmetric tools to minimise distortion during hardening. M4 Stress Relieved has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 890 MPa (129 ksi) — stronger than 73% of steel grades. Elongation at break is 11% and the elastic modulus is 217 GPa (31.5 Msi). M4 Stress Relieved 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; Stress Relieved is available on request or by drawing note.
Advantages
- High service temperature — 540°C (1,004 °F), better than 93% of steel grades
Limitations
- Low fracture toughness — 23 MPa·√m (20.9 ksi·√in), worse than 98% of steel grades
- Difficult to machine — 24/100, worse than 95% of steel grades
- High embodied carbon — 4.2 kg CO₂/kg, worse than 95% 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 Stress Relieved properties
Typical room-temperature values for M4 Stress Relieved; 23 are specific to this condition. Other listed values are M4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
M4 Stress Relieved 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 Stress Relieved has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 890 MPa (129 ksi) — stronger than 73% of steel grades. Elongation at break is 11% and the elastic modulus is 217 GPa (31.5 Msi).
Thermal6
M4 Stress Relieved is rated for continuous service to 540°C (1,004 °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 Stress Relieved 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 Stress Relieved 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 Stress Relieved's machinability is poor (24/100, worse than 95% of steel grades); weldability poor (15/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with M4 Stress Relieved
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 Stress Relieved — frequently asked
What is M4 Stress Relieved used for?
M4 Stress Relieved is typically used for broaches, cutting tools and milling cutters. In short: high-impact toughness.
What is the yield strength of M4 Stress Relieved?
M4 Stress Relieved has a typical yield strength of 560 MPa (81.2 ksi) and a tensile strength of 890 MPa (129 ksi) — stronger than 73% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is M4 Stress Relieved easy to machine?
Not especially — machinability is rated poor (24/100, worse than 95% 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 Stress Relieved 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 Stress Relieved?
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 Stress Relieved 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 Stress Relieved?
M4 Stress Relieved is rated for continuous use to about 540°C (1,004 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in M4 Stress Relieved?
Yes — M4 Stress Relieved is available for CNC machining; every part is priced by an engineer rather than instantly. 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.