Steel 38CrMoAl · finish state
Steel 38CrMoAl Q&T+Nitrided
Properties of the Q&T+Nitrided condition, compared with the other 38CrMoAl tempers.
The intended service condition: >900 HV AlN-hardened case for wear, galling and fatigue resistance on a tough core.
What is 38CrMoAl Q&T+Nitrided?
38CrMoAl Q&T+Nitrided is 38CrMoAl supplied in the Q&T+Nitrided condition — the intended service condition: >900 HV AlN-hardened case for wear, galling and fatigue resistance on a tough core. 38CrMoAl Q&T+Nitrided has a yield strength of 880 MPa (128 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 90% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi). 38CrMoAl Q&T+Nitrided 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). Q&T is the default condition FabDigit quotes; Q&T+Nitrided is available on request or by drawing note.
Advantages
- Good corrosion resistance — 25/100, better than 91% of steel grades
- High strength — 880 MPa (128 ksi), better than 90% of steel grades
- High service temperature — 500°C (932 °F), better than 90% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Difficult to machine — 5/100, worse than 100% of steel grades
- Difficult to weld — 3/100, worse than 100% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
38CrMoAl Q&T+Nitrided properties
Typical room-temperature values for 38CrMoAl Q&T+Nitrided — 12 properties are specific to this condition; the rest are grade-level values shared by every 38CrMoAl temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
38CrMoAl Q&T+Nitrided 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
38CrMoAl Q&T+Nitrided has a yield strength of 880 MPa (128 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 90% of steel grades. Elongation at break is 14% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
38CrMoAl Q&T+Nitrided is rated for continuous service to 500°C (932 °F). It conducts heat at 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 72% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
38CrMoAl Q&T+Nitrided conducts electricity at 7.8 % IACS, worse than 58% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (25/100), better than 91% of steel grades.
Sustainability4
Producing a kilogram of 38CrMoAl Q&T+Nitrided takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
38CrMoAl Q&T+Nitrided's machinability is not recommended (5/100, worse than 100% of steel grades); weldability not recommended (3/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 38CrMoAl tempers and conditions
38CrMoAl is also supplied in 7 other conditions. The full side-by-side table is on the 38CrMoAl overview.
- Q&TDefaultStandard delivery/core condition: tough tempered-sorbite core that will not soften during subsequent nitriding.880 MPa yield · 32 HRC
- Q&T 32-36 HRCChosen for extruder screws/barrels and shafts needing maximum core support under the nitrided case.950 MPa yield · 34 HRC
- Q&T+NitridedThe intended service condition: >900 HV AlN-hardened case for wear, galling and fatigue resistance on a tough core.880 MPa yield · 68 HRC
- Q&T 28-32 HRCOrder this when a machinable but strong core hardness must be guaranteed before nitriding.830 MPa yield · 30 HRC
- AnnealedSoftest condition for heavy machining, deep-hole drilling and cold straightening before final Q&T.450 MPa yield · 215 HB
Working with 38CrMoAl Q&T+Nitrided
Is 38CrMoAl easy to machine?
Machine in the annealed or Q&T (28–32 HRC) state with rigid setups and coated carbide; leave 0.05–0.15 mm grinding stock because nitriding grows and slightly distorts parts, and never machine the nitrided case except by grinding/lapping.
Can 38CrMoAl be welded?
Effectively non-weldable for service parts — high hardenability plus ~1 % Al causes cracking and hard HAZ; if unavoidable, preheat 300–400 °C, use low-hydrogen matched consumables and re-temper immediately.
Can 38CrMoAl be formed, bent or molded?
Hot forge 1100–850 °C with slow cooling and mandatory normalise/anneal; cold forming is limited to light straightening in the annealed condition.
What surface finishes work on 38CrMoAl?
Gas or ion nitride at 500–540 °C after stress relief for a 0.3–0.6 mm case >900 HV; lap or grind off the brittle white layer, then oil, phosphate, black-oxide or chrome plate since the base steel rusts readily.
38CrMoAl 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 | 0.35 – 0.42 | 0.38 |
| Si | 0.2 – 0.45 | 0.3 |
| Mn | 0.3 – 0.6 | 0.45 |
| Cr | 1.35 – 1.65 | 1.5 |
| Mo | 0.15 – 0.25 | 0.2 |
| Alforms hard AlN in the nitrided case | 0.7 – 1.1 | 0.9 |
| Niresidual | ≤ 0.3 | — |
| Curesidual | ≤ 0.3 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
38CrMoAl Q&T+Nitrided — frequently asked
What is 38CrMoAl Q&T+Nitrided used for?
38CrMoAl Q&T+Nitrided is typically used for nitrided drive and spindle shafts, gear and pinion surfaces, extruder screws and barrels, hydraulic piston rods, valve stems and spindles and precision gauges and measuring tools. In short: nitridable Cr-Mo-Al bar.
What is the yield strength of 38CrMoAl Q&T+Nitrided?
38CrMoAl Q&T+Nitrided has a typical yield strength of 880 MPa (128 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 90% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 38CrMoAl Q&T+Nitrided easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 100% of steel grades). Machine in the annealed or Q&T (28–32 HRC) state with rigid setups and coated carbide; leave 0.05–0.15 mm grinding stock because nitriding grows and slightly distorts parts, and never machine the nitrided case except by grinding/lapping.
Can 38CrMoAl Q&T+Nitrided be welded?
Not readily — weldability is rated not recommended (3/100). Effectively non-weldable for service parts — high hardenability plus ~1 % Al causes cracking and hard HAZ; if unavoidable, preheat 300–400 °C, use low-hydrogen matched consumables and re-temper immediately.
What surface finishes work on 38CrMoAl Q&T+Nitrided?
Gas or ion nitride at 500–540 °C after stress relief for a 0.3–0.6 mm case >900 HV; lap or grind off the brittle white layer, then oil, phosphate, black-oxide or chrome plate since the base steel rusts readily.
Can 38CrMoAl Q&T+Nitrided be formed, bent or molded?
Hot forge 1100–850 °C with slow cooling and mandatory normalise/anneal; cold forming is limited to light straightening in the annealed condition.
What is the maximum service temperature of 38CrMoAl Q&T+Nitrided?
38CrMoAl Q&T+Nitrided 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.
What is the difference between 38CrMoAl Q&T and 38CrMoAl-HR?
Q&T is the default condition — standard delivery/core condition: tough tempered-sorbite core that will not soften during subsequent nitriding. HR: cheapest mill supply condition for stock that will be fully heat treated by the user. Yield strength is 880 MPa in Q&T versus 600 MPa in HR.
Can FabDigit make parts in 38CrMoAl Q&T+Nitrided?
Yes — 38CrMoAl Q&T+Nitrided is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- GB/T 3077 Alloy structural steels — SAC (China) (2015)
- EN 10085 Nitriding steels — 41CrAlMo7-10 (1.8509) — CEN (2001)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels — ASM International (1990)
- ASM Handbook Vol. 4A: Steel Heat Treating — Nitriding — ASM International (2013)
- Nitriding steel 1.8509 / N135M datasheet — Böhler / voestalpine (2020)
- 38CrMoAl — Mysteel / 1688 (2026)
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.