Steel S7 · temper · default condition
Steel S7 Annealed
Properties of the Annealed condition, compared with the other S7 tempers.
Standard stocked condition: machine, then harden and temper.
What is S7 Annealed?
S7 Annealed is S7 in the Annealed temper — standard stocked condition: machine, then harden and temper. S7 Annealed has a yield strength of 530 MPa (76.9 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 69% of steel grades. Elongation at break is 18% and the elastic modulus is 207 GPa (30 Msi). S7 Annealed has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F).
Advantages
- Polishes to a fine finish — 75/100, better than 94% of steel grades
- High service temperature — 500°C (932 °F), better than 90% of steel grades
Limitations
- High embodied carbon — 2.7 kg CO₂/kg, 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 — 25/100, worse than 77% of steel grades
S7 Annealed properties
Typical room-temperature values for S7 Annealed — 9 properties are specific to this condition; the rest are grade-level values shared by every S7 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
S7 Annealed has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
S7 Annealed has a yield strength of 530 MPa (76.9 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 69% of steel grades. Elongation at break is 18% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
S7 Annealed is rated for continuous service to 500°C (932 °F). It conducts heat at 25 W/m·K (14.4 BTU/hr·ft·°F), worse than 88% of steel grades. Thermal expansion is 12.6 µm/m·K (7 µin/in·°F).
Electrical2
S7 Annealed has an electrical resistivity of 6×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is poor (18/100), better than 83% of steel grades.
Sustainability4
Producing a kilogram of S7 Annealed takes about 36 MJ of energy and emits 2.7 kg of CO₂ — more than 88% of steel grades. Typical recycled content is 40%.
Manufacturability7
S7 Annealed's machinability is fair (50/100, worse than 53% of steel grades); weldability poor (25/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other S7 tempers and conditions
S7 is also supplied in 6 other conditions. The full side-by-side table is on the S7 overview.
- AnnealedDefaultStandard stocked condition: machine, then harden and temper.530 MPa yield · 15 HRC
- H&T 56-58 HRCMaximum wear/indentation resistance for punches and shear blades where loads are not severely shock-loaded.1,750 MPa yield · 57 HRC
- H&T 54-56 HRCBalanced hardness/toughness band most used for cold punches, chisels and rivet sets.1,650 MPa yield · 55 HRC
- Hardened & TemperedGeneric in-service condition when a specific hardness band is not called out.1,600 MPa yield · 56 HRC
- Q&TOrder-to-hardness condition, typically 50–58 HRC depending on tempering temperature.1,550 MPa yield · 54 HRC
- H&T 50-52 HRCChoose when impact and gross shock dominate (heavy shear knives, forming dies, tooling for warm work).1,450 MPa yield · 51 HRC
Working with S7 Annealed
Is S7 easy to machine?
Machine in the annealed condition (~200 HB) with rigid setups and moderate speeds; leave 0.3–0.8 mm for finish grinding after hardening since air quench still moves parts slightly.
Can S7 be welded?
Weld only for repair: preheat 200–320 °C, use matching or Cr-Mo tool-steel filler, keep interpass temperature and temper immediately at 15–30 °C below the original tempering temperature.
Can S7 be formed, bent or molded?
Hot work at 1050–900 °C with slow cooling and a full anneal (~800–830 °C, slow cool) afterwards; austenitize 925–955 °C, air quench in still air, double temper 205–480 °C to the target hardness.
What surface finishes work on S7?
Takes a good mold polish when hardened; protect the non-stainless surface with black oxide, phosphate, hard chrome, nitriding or PVD, and oil parts in storage.
S7 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 | 0.45 – 0.55 | 0.5 |
| Si | 0.2 – 1 | 0.4 |
| Mn | 0.2 – 0.9 | 0.7 |
| Cr | 3 – 3.5 | 3.25 |
| Mo | 1.3 – 1.8 | 1.4 |
| Voptional; 1.2355 typically ~0.2 V | ≤ 0.35 | 0.25 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
S7 Annealed — frequently asked
What is S7 Annealed used for?
S7 Annealed is typically used for jackhammer bits, rivet sets and punches. In short: extreme shock resistance.
What is the yield strength of S7 Annealed?
S7 Annealed has a typical yield strength of 530 MPa (76.9 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 69% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is S7 Annealed easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machine in the annealed condition (~200 HB) with rigid setups and moderate speeds; leave 0.3–0.8 mm for finish grinding after hardening since air quench still moves parts slightly.
Can S7 Annealed be welded?
Not readily — weldability is rated poor (25/100). Weld only for repair: preheat 200–320 °C, use matching or Cr-Mo tool-steel filler, keep interpass temperature and temper immediately at 15–30 °C below the original tempering temperature.
What surface finishes work on S7 Annealed?
Takes a good mold polish when hardened; protect the non-stainless surface with black oxide, phosphate, hard chrome, nitriding or PVD, and oil parts in storage.
Can S7 Annealed be formed, bent or molded?
Hot work at 1050–900 °C with slow cooling and a full anneal (~800–830 °C, slow cool) afterwards; austenitize 925–955 °C, air quench in still air, double temper 205–480 °C to the target hardness.
What is the maximum service temperature of S7 Annealed?
S7 Annealed is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in S7 Annealed?
Yes — S7 Annealed is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A681 — Alloy Tool Steels — ASTM International (2015)
- EN ISO 4957 / DIN 1.2355 (50CrMoV13-15) — CEN / DIN (2018)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Specialty Handbook: Tool Materials — ASM International (1995)
- S7 shock-resisting tool steel datasheets — Crucible / Böhler-Uddeholm / Hudson Tool Steel (2022)
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.