Steel 8CrMo16-5 +SR (Stress relieved)
Heat-treated state
EN 8CrMo16-5
Intermediate step for long or thin precision parts: relieves machining stresses before finish cut and nitriding to hold tolerance.
Values for the +SR condition
Other 8CrMo16-5 tempers and conditions
8CrMo16-5 is listed in 5 conditions; see the grade overview at 8CrMo16-5.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for maximum machinability during roughing or for parts to be hardened later. | 380 | 600 | 22 | 195 HB | — |
Normalized | Pick for a uniform fine-grained structure on forgings before final quenching and tempering. | 450 | 680 | 19 | 18 HRC | 5.8 % IACS |
+SRThis page Stress relieved | Intermediate step for long or thin precision parts: relieves machining stresses before finish cut and nitriding to hold tolerance. | 580 | 790 | 16 | 23 HRC | 5.8 % IACS |
+QTDefault Quenched and tempered | Standard stocked condition: tempered above the later nitriding temperature so the part is dimensionally stable and ready to finish-machine and nitride. | 590 | 800 | 16 | 25 HRC | — |
+QT + Nitrided | Final service condition: choose when maximum surface hardness, wear and scuffing resistance with negligible distortion is required. | 590 | 800 | 14 | 67 HRC | — |
What is 8CrMo16-5 +SR?
8CrMo16-5 +SR is 8CrMo16-5 heat treated to +SR — intermediate step for long or thin precision parts: relieves machining stresses before finish cut and nitriding to hold tolerance. 8CrMo16-5 +SR has a yield strength of 580 MPa (84.1 ksi) and a tensile strength of 790 MPa (115 ksi) — stronger than 75% of steel grades. Elongation at break is 16% and the elastic modulus is 210 GPa (30.5 Msi). 8CrMo16-5 +SR has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,450°C (2,642 °F). +QT is the default condition FabDigit quotes; +SR is available on request or by drawing note.
Advantages
- High service temperature — 500°C (932 °F), better than 90% of steel grades
- Good corrosion resistance — 22/100, better than 90% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- High strength — 580 MPa (84.1 ksi), better than 75% of steel grades
Limitations
- Low electrical conductivity — 5.8 % IACS, worse than 79% of steel grades
- Poor heat conductor — 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades
8CrMo16-5 +SR properties
Typical room-temperature values for 8CrMo16-5 +SR; 23 are specific to this condition. Other listed values are 8CrMo16-5 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
8CrMo16-5 +SR has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
8CrMo16-5 +SR has a yield strength of 580 MPa (84.1 ksi) and a tensile strength of 790 MPa (115 ksi) — stronger than 75% of steel grades. Elongation at break is 16% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
8CrMo16-5 +SR is rated for continuous service to 500°C (932 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
8CrMo16-5 +SR conducts electricity at 5.8 % IACS, worse than 79% of steel grades.
Chemical & Environmental2
Corrosion resistance is poor (22/100), better than 90% of steel grades.
Sustainability4
Producing a kilogram of 8CrMo16-5 +SR takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
8CrMo16-5 +SR's machinability is good (56/100, better than 71% of steel grades); weldability fair (35/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 8CrMo16-5 +SR
Is 8CrMo16-5 easy to machine?
Machine in +A or +QT with sharp carbide tooling and rigid setups; leave 0.05–0.15 mm finish stock, then stress relieve and finish-cut before nitriding — nitrided surfaces are essentially only grindable.
Can 8CrMo16-5 be welded?
Not intended for welding; if unavoidable, weld before nitriding with matching low-C Cr-Mo filler, preheat 250–350 °C and post-weld temper — never weld a nitrided part (compound layer causes porosity and cracks).
Can 8CrMo16-5 be formed, bent or molded?
Hot forge 1100–850 °C with slow cooling and normalize afterwards; cold forming is limited because of the high alloy content and Q&T strength.
What surface finishes work on 8CrMo16-5?
Gas or plasma nitride at 500–540 °C for 900–1050 HV surface; grind or lap after nitriding, optionally post-oxidise or black-oxide for mild corrosion protection — anodising is not applicable.
8CrMo16-5 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 |
|---|---|---|
| Clow carbon keeps core soft and distortion low | 0.05 – 0.12 | 0.08 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.4 – 0.7 | 0.55 |
| P | ≤ 0.03 | — |
| Smax; low-S melts preferred for polished/nitrided surfaces | ≤ 0.04 | — |
| Crprimary nitride former | 3.8 – 4.5 | 4.1 |
| Motemper-embrittlement resistance, secondary hardening | 0.4 – 0.6 | 0.5 |
| Fe | balance | — |
8CrMo16-5 +SR — frequently asked
What is 8CrMo16-5 +SR used for?
8CrMo16-5 +SR is typically used for precision nitrided components, valve parts, wear-resistant sleeves and injection molding tooling. In short: highest case hardness nitriding steel; stable dimensions after nitriding; moderate core strength.
What is the yield strength of 8CrMo16-5 +SR?
8CrMo16-5 +SR has a typical yield strength of 580 MPa (84.1 ksi) and a tensile strength of 790 MPa (115 ksi) — stronger than 75% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is 8CrMo16-5 +SR easy to machine?
Reasonably — machinability is rated good (56/100, better than 71% of steel grades). Machine in +A or +QT with sharp carbide tooling and rigid setups; leave 0.05–0.15 mm finish stock, then stress relieve and finish-cut before nitriding — nitrided surfaces are essentially only grindable.
Can 8CrMo16-5 +SR be welded?
With care — weldability is rated fair (35/100). Not intended for welding; if unavoidable, weld before nitriding with matching low-C Cr-Mo filler, preheat 250–350 °C and post-weld temper — never weld a nitrided part (compound layer causes porosity and cracks).
What surface finishes work on 8CrMo16-5 +SR?
Gas or plasma nitride at 500–540 °C for 900–1050 HV surface; grind or lap after nitriding, optionally post-oxidise or black-oxide for mild corrosion protection — anodising is not applicable.
Can 8CrMo16-5 +SR be formed, bent or molded?
Hot forge 1100–850 °C with slow cooling and normalize afterwards; cold forming is limited because of the high alloy content and Q&T strength.
What is the maximum service temperature of 8CrMo16-5 +SR?
8CrMo16-5 +SR 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.
Sources
- EN 10085 — Nitriding steels: technical delivery conditions — CEN (2001)
- EN 10027-2 — Designation systems for steels, material numbers — CEN (2015)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 4A/4D — Steel Heat Treating and Case Hardening (Nitriding) — ASM International (2014)
- European special-steel mill datasheets for nitriding steel bar (1.8527 class) — various (Böhler / Deutsche Edelstahlwerke class data) (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.