Steel S4 Annealed
Temper · default condition
AISI/SAE S4 · UNS T41904
Stock condition for machining, forming and drilling before hardening.
Values for the Annealed condition
Other S4 tempers and conditions
S4 is listed in 7 conditions; see the grade overview at S4.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefaultThis page spheroidize annealed bar/plate, machinable condition | Stock condition for machining, forming and drilling before hardening. | 430 | 720 | 25 | 210 HB | — |
Hot rolled | Mill-supplied stock for forging shops that will anneal or heat treat in-house. | 620 | 950 | 15 | 29 HRC | — |
Normalized | Used to refine forged structure prior to spheroidize annealing; not a finished tool condition. | 700 | 1,100 | 12 | 34 HRC | 3 % IACS |
Hardened & tempered ~425 °C | Maximum-toughness condition for heavy shock work such as jackhammer and chipping tools. | 1,420 | 1,700 | 10 | 50 HRC | — |
Hardened & tempered ~315 °C | Balanced hardness/toughness for rivet sets, shear blades and pneumatic tool bits. | 1,550 | 1,900 | 7 | 55 HRC | — |
Hardened & tempered ~205 °C | Maximum hardness/wear condition for chisels and punch tips where edge retention outweighs toughness. | 1,750 | 2,100 | 4 | 58 HRC | — |
As-quenched | Untempered martensite; must be tempered immediately — brittle and crack-prone in this state. | 1,900 | 2,200 | 1 | 62 HRC | 2.7 % IACS |
What is S4 Annealed?
S4 Annealed is S4 in the Annealed temper — stock condition for machining, forming and drilling before hardening. S4 Annealed has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 720 MPa (104 ksi) — weaker than 51% of steel grades. Elongation at break is 25% and the elastic modulus is 207 GPa (30 Msi). S4 Annealed has a density of 7.79 g/cm³ (0.281 lb/in³), lighter than 90% of steel grades. It melts at 1,420°C (2,588 °F).
Advantages
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
Limitations
- Low electrical conductivity — 3.1 % IACS, worse than 89% of steel grades
- Poor heat conductor — 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 88% of steel grades
- Difficult to weld — 22/100, worse than 81% of steel grades
S4 Annealed properties
Typical room-temperature values for S4 Annealed; 13 are specific to this condition. Other listed values are S4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
S4 Annealed has a density of 7.79 g/cm³ (0.281 lb/in³), lighter than 90% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical13
S4 Annealed has a yield strength of 430 MPa (62.4 ksi) and a tensile strength of 720 MPa (104 ksi) — weaker than 51% of steel grades. Elongation at break is 25% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
S4 Annealed is rated for continuous service to 400°C (752 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 88% of steel grades. Thermal expansion is 12.4 µm/m·K (6.89 µin/in·°F).
Electrical3
S4 Annealed conducts electricity at 3.1 % IACS, worse than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of S4 Annealed takes about 33 MJ of energy and emits 2.4 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 35%.
Manufacturability7
S4 Annealed's machinability is fair (48/100, worse than 57% of steel grades); weldability poor (22/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S4 Annealed
Is S4 easy to machine?
Machine only in the annealed (≤235 HB) condition with sharp carbide or cobalt HSS; the ~2 % Si is abrasive, so use rigid setups, generous coolant and finish-grind after hardening.
Can S4 be welded?
Poor weldability — preheat 260–320 °C, use matched or low-hydrogen filler, weld with minimum heat input and temper immediately at the tool's tempering temperature to avoid quench cracks.
Can S4 be formed, bent or molded?
Forge 1040–1150 °C, stop above 900 °C and cool slowly, then spheroidize anneal at ~790 °C; cold forming is limited to mild bending of annealed stock.
What surface finishes work on S4?
Protect against decarburization during austenitizing (neutral salt, vacuum or stop-off paint), then finish by grinding and apply oil, black oxide, phosphate or nitriding for corrosion and galling resistance.
S4 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 | 0.5 – 0.65 | 0.57 |
| Sihigh Si gives temper resistance and hardenability | 1.75 – 2.25 | 2 |
| Mn | 0.6 – 0.95 | 0.8 |
| Crresidual/optional in ASTM A681 | ≤ 0.35 | 0.2 |
| Voptional grain refiner | ≤ 0.35 | 0.2 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
S4 Annealed — frequently asked
What is S4 Annealed used for?
S4 Annealed is typically used for shear blades, rivet sets, punches and chisels. In short: high-toughness impact steel; high-silicon S grade; not a wear grade.
What is the yield strength of S4 Annealed?
S4 Annealed has a typical yield strength of 430 MPa (62.4 ksi) and a tensile strength of 720 MPa (104 ksi) — weaker than 51% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is S4 Annealed easy to machine?
Reasonably — machinability is rated fair (48/100, worse than 57% of steel grades). Machine only in the annealed (≤235 HB) condition with sharp carbide or cobalt HSS; the ~2 % Si is abrasive, so use rigid setups, generous coolant and finish-grind after hardening.
Can S4 Annealed be welded?
Not readily — weldability is rated poor (22/100). Poor weldability — preheat 260–320 °C, use matched or low-hydrogen filler, weld with minimum heat input and temper immediately at the tool's tempering temperature to avoid quench cracks.
What surface finishes work on S4 Annealed?
Protect against decarburization during austenitizing (neutral salt, vacuum or stop-off paint), then finish by grinding and apply oil, black oxide, phosphate or nitriding for corrosion and galling resistance.
Can S4 Annealed be formed, bent or molded?
Forge 1040–1150 °C, stop above 900 °C and cool slowly, then spheroidize anneal at ~790 °C; cold forming is limited to mild bending of annealed stock.
What is the maximum service temperature of S4 Annealed?
S4 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.
What is the difference between S4 Annealed and S4-AQ?
Annealed is the default condition — stock condition for machining, forming and drilling before hardening. AQ: untempered martensite; must be tempered immediately — brittle and crack-prone in this state. Yield strength is 430 MPa in Annealed versus 1,900 MPa in AQ.
Sources
- ASTM A681 Standard Specification for Tool Steels Alloy — ASTM International (2022)
- SAE J437/J438 Tool and Die Steels — SAE International (2007)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys (Tool Steels) — ASM International (1990)
- ASM Specialty Handbook: Tool Materials — ASM International (1995)
- ASM Handbook Vol.16: Machining (tool steel machinability ratings) — ASM International (1989)
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.