Steel S7 · hardness band
Steel S7 H&T 50-52 HRC
Properties of the H&T 50-52 HRC condition, compared with the other S7 tempers.
Choose when impact and gross shock dominate (heavy shear knives, forming dies, tooling for warm work).
What is S7 H&T 50-52 HRC?
S7 H&T 50-52 HRC is S7 heat treated to H&T 50-52 HRC — choose when impact and gross shock dominate (heavy shear knives, forming dies, tooling for warm work). S7 H&T 50-52 HRC has a yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 97% of steel grades. Elongation at break is 9% and the elastic modulus is 207 GPa (30 Msi). S7 H&T 50-52 HRC 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). Annealed is the default condition FabDigit quotes; H&T 50-52 HRC is available on request or by drawing note.
Advantages
- High strength — 1,450 MPa (210 ksi), better than 97% of steel grades
- Polishes to a fine finish — 75/100, better than 94% of steel grades
Limitations
- Difficult to machine — 18/100, worse than 98% of steel grades
- Limited ductility — 9%, worse than 93% of steel grades
- 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 H&T 50-52 HRC properties
Typical room-temperature values for S7 H&T 50-52 HRC — 11 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 H&T 50-52 HRC 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 H&T 50-52 HRC has a yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 97% of steel grades. Elongation at break is 9% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
S7 H&T 50-52 HRC is rated for continuous service to 425°C (797 °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 H&T 50-52 HRC 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 H&T 50-52 HRC 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 H&T 50-52 HRC's machinability is poor (18/100, worse than 98% of steel grades); weldability poor (25/100); formability fair (35/100).
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 H&T 50-52 HRC
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 H&T 50-52 HRC — frequently asked
What is S7 H&T 50-52 HRC used for?
S7 H&T 50-52 HRC is typically used for jackhammer bits, rivet sets and punches. In short: extreme shock resistance.
What is the yield strength of S7 H&T 50-52 HRC?
S7 H&T 50-52 HRC has a typical yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 97% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is S7 H&T 50-52 HRC easy to machine?
Not especially — machinability is rated poor (18/100, worse than 98% 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 H&T 50-52 HRC 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 H&T 50-52 HRC?
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 H&T 50-52 HRC 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 H&T 50-52 HRC?
S7 H&T 50-52 HRC is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in S7 H&T 50-52 HRC?
Yes — S7 H&T 50-52 HRC 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.