Steel S7 Nitrided
Finish state
AISI/SAE S7 · UNS T41907 · EN 1.2355, 50CrMoV13-15
Add when surface wear or galling limits tool life; core properties stay those of the tempered condition.
Values for the Nitrided condition
Other S7 tempers and conditions
S7 is listed in 6 conditions; see the grade overview at S7.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault soft, as-supplied bar/plate for machining | Standard stocked condition: machine, then harden and temper. | 530 | 830 | 18 | 15 HRC | 2.9 % IACS |
Hardened & Tempered 50–52 HRC | Choose when impact and gross shock dominate (heavy shear knives, forming dies, tooling for warm work). | 1,450 | 1,750 | 9 | 51 HRC | — |
austenitize 925–955 °C, air quench, temper (general) | Generic in-service condition when a specific hardness band is not called out. | 1,600 | 2,000 | 6 | 56 HRC | — |
NitridedThis page case ~900–1100 HV | Add when surface wear or galling limits tool life; core properties stay those of the tempered condition. | 1,600 | 1,950 | 6 | 55 HRC | 2.7 % IACS |
Hardened & Tempered 54–56 HRC | Balanced hardness/toughness band most used for cold punches, chisels and rivet sets. | 1,650 | 2,000 | 6 | 55 HRC | — |
Hardened & Tempered 56–58 HRC | Maximum wear/indentation resistance for punches and shear blades where loads are not severely shock-loaded. | 1,750 | 2,150 | 4 | 57 HRC | — |
What is S7 Nitrided?
S7 Nitrided is S7 supplied in the Nitrided condition — add when surface wear or galling limits tool life; core properties stay those of the tempered condition. S7 Nitrided has a yield strength of 1,600 MPa (232 ksi) and a tensile strength of 1,950 MPa (283 ksi) — stronger than 98% of steel grades. Elongation at break is 6% and the elastic modulus is 207 GPa (30 Msi). S7 Nitrided 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; Nitrided is available on request or by drawing note.
Advantages
- High strength — 1,600 MPa (232 ksi), better than 98% of steel grades
- Good corrosion resistance — 28/100, better than 94% of steel grades
- Polishes to a fine finish — 75/100, better than 94% of steel grades
- High service temperature — 480°C (896 °F), better than 88% of steel grades
Limitations
- Difficult to machine — 5/100, worse than 100% of steel grades
- Difficult to weld — 5/100, worse than 100% of steel grades
- Limited formability — 2/100, worse than 100% of steel grades
- Limited ductility — 6%, worse than 97% of steel grades
- Low electrical conductivity — 2.7 % IACS, worse than 96% of steel grades
S7 Nitrided properties
Typical room-temperature values for S7 Nitrided; 21 are specific to this condition. Other listed values are S7 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
S7 Nitrided 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).
Mechanical17
S7 Nitrided has a yield strength of 1,600 MPa (232 ksi) and a tensile strength of 1,950 MPa (283 ksi) — stronger than 98% of steel grades. Elongation at break is 6% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
S7 Nitrided is rated for continuous service to 480°C (896 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), worse than 90% of steel grades. Thermal expansion is 12.6 µm/m·K (7 µin/in·°F).
Electrical3
S7 Nitrided conducts electricity at 2.7 % IACS, worse than 96% of steel grades.
Chemical & Environmental2
Corrosion resistance is poor (28/100), better than 94% of steel grades.
Sustainability4
Producing a kilogram of S7 Nitrided takes about 36 MJ of energy and emits 2.7 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 40%.
Manufacturability7
S7 Nitrided's machinability is not recommended (5/100, worse than 100% of steel grades); weldability not recommended (5/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S7 Nitrided
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 Nitrided — frequently asked
What is S7 Nitrided used for?
S7 Nitrided is typically used for jackhammer bits, rivet sets and punches. In short: extreme shock resistance.
What is the yield strength of S7 Nitrided?
S7 Nitrided has a typical yield strength of 1,600 MPa (232 ksi) and a tensile strength of 1,950 MPa (283 ksi) — stronger than 98% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is S7 Nitrided easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 100% 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 Nitrided be welded?
Not readily — weldability is rated not recommended (5/100). 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 Nitrided?
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 Nitrided 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 Nitrided?
S7 Nitrided is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in S7 Nitrided?
Yes — S7 Nitrided 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 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.