Steel 1.2738 Nitrided
Finish state
EN 1.2738
Apply gas or plasma nitriding after the pre-hardened part is finish machined to add a ~900–1000 HV case against cavity wear and sticking; the core retains pre-hardened properties.
Values for the Nitrided condition
Other 1.2738 tempers and conditions
1.2738 is listed in 7 conditions; see the grade overview at 1.2738.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault soft annealed (≤235 HB) for deep machining / re-hardening | Pick soft annealed stock at =235 HB for blanks needing heavy roughing, cold work or deep-hole drilling before through hardening and tempering; as-delivered strength and wear resistance are low. | 470 | 760 | 20 | 19 HRC | — |
Pre-hardened | Use the standard 28–34 HRC (290–330 HB) pre-hardened delivery to cut cavities and go straight into production with no further heat treatment and no quench distortion risk. | 860 | 1,000 | 14 | 31 HRC | — |
NitridedThis page gas/plasma nitrided surface on pre-hardened core (case ~900–1000 HV) | Apply gas or plasma nitriding after the pre-hardened part is finish machined to add a ~900–1000 HV case against cavity wear and sticking; the core retains pre-hardened properties. | 860 | 1,000 | 12 | 31 HRC | 7 % IACS |
electroslag-remelted, pre-hardened 30–34 HRC, mirror-polish / texturing grade | Use the electroslag-remelted, 30–34 HRC pre-hardened grade for optical parts, high-gloss surfaces and deep-etched textures, where low inclusion content gives consistent polishing and texturing. | 880 | 1,030 | 16 | 32 HRC | 7 % IACS |
higher-hardness pre-hardened delivery, ~36–40 HRC (340–380 HB) | Pick the 36–40 HRC (340–380 HB) pre-hardened delivery for long-life tools and filled-resin molds; wear resistance and polishability improve while machinability drops. | 1,030 | 1,200 | 12 | 38 HRC | — |
Quenched and tempered | Choose re-austenitizing at 850–880 °C with oil or air quench and temper to 40–46 HRC for small or high-wear inserts; accept quench distortion and the finish machining it forces. | 1,200 | 1,400 | 10 | 43 HRC | — |
Hardened | Choose the as-quenched plus low-temper 50–52 HRC state, the maximum hardness attainable, only for small wear inserts; toughness is low and distortion and cracking risk are significant. | 1,450 | 1,700 | 6 | 51 HRC | 6.5 % IACS |
What is 1.2738 Nitrided?
1.2738 Nitrided is 1.2738 supplied in the Nitrided condition — apply gas or plasma nitriding after the pre-hardened part is finish machined to add a ~900–1000 HV case against cavity wear and sticking; the core retains pre-hardened properties. 1.2738 Nitrided has a yield strength of 860 MPa (125 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 89% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). 1.2738 Nitrided has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% 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
- Polishes to a fine finish — 78/100, better than 95% of steel grades
- High strength — 860 MPa (125 ksi), better than 89% of steel grades
- High service temperature — 450°C (842 °F), better than 86% of steel grades
Limitations
- Difficult to machine — 8/100, worse than 100% of steel grades
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited formability — 3/100, worse than 99% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Poor heat conductor — 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 82% of steel grades
1.2738 Nitrided properties
Typical room-temperature values for 1.2738 Nitrided; 22 are specific to this condition. Other listed values are 1.2738 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
1.2738 Nitrided has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
1.2738 Nitrided has a yield strength of 860 MPa (125 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 89% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
1.2738 Nitrided is rated for continuous service to 450°C (842 °F). It conducts heat at 32 W/m·K (18.5 BTU/hr·ft·°F), worse than 82% of steel grades. Thermal expansion is 12.4 µm/m·K (6.89 µin/in·°F).
Electrical3
1.2738 Nitrided conducts electricity at 7 % IACS, worse than 74% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (20/100), better than 87% of steel grades.
Sustainability4
Producing a kilogram of 1.2738 Nitrided takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability7
1.2738 Nitrided's machinability is not recommended (8/100, worse than 100% of steel grades); weldability not recommended (10/100); formability not recommended (3/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1.2738 Nitrided
Is 1.2738 easy to machine?
In the prehardened 28–34 HRC condition it mills and drills predictably with coated carbide, moderate cutting speeds and ample coolant. On deep cavity roughing leave 0.3–0.5 mm finishing stock so stress-relief movement can be machined away.
Can 1.2738 be welded?
Preheat to 250–325 °C before repair welding, use matching mould-steel filler at low current with multiple small passes, then temper immediately just below the original tempering temperature to restore hardness and prevent cracking.
Can 1.2738 be formed, bent or molded?
Not cold formed; stock is supplied hot-rolled or forged and quenched and tempered. If re-hardening is needed, austenitise at 850–880 °C, oil quench or pressurised gas quench, then temper twice at 550–620 °C.
What surface finishes work on 1.2738?
Polishes to a mirror finish and suits chemical texturing/photo-etching. It rusts in service, so hard chrome, electroless nickel, nitriding or PVD is common, and idle tools should be coated with rust-preventive oil.
1.2738 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 – 0.45 | 0.4 |
| Si | 0.2 – 0.4 | 0.3 |
| Mn | 1.3 – 1.6 | 1.45 |
| Cr | 1.8 – 2.1 | 1.95 |
| Mo | 0.15 – 0.25 | 0.2 |
| Niadded versus 1.2311; increases hardenability | 0.9 – 1.2 | 1.05 |
| Pimpurity upper limit | ≤ 0.03 | — |
| Simpurity limit; mirror-finish grade usually ≤ 0.005 | ≤ 0.03 | — |
| Fe | balance | — |
1.2738 Nitrided — frequently asked
What is 1.2738 Nitrided used for?
1.2738 Nitrided is typically used for injection mould cavity and core plates, mould inserts, large mould bases and bolsters, photo-etched (textured) cosmetic tooling, polished housing and lens cavities and blow mould bodies. In short: workhorse cavity mold plate.
What is the yield strength of 1.2738 Nitrided?
1.2738 Nitrided has a typical yield strength of 860 MPa (125 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 89% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 1.2738 Nitrided easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 100% of steel grades). In the prehardened 28–34 HRC condition it mills and drills predictably with coated carbide, moderate cutting speeds and ample coolant. On deep cavity roughing leave 0.3–0.5 mm finishing stock so stress-relief movement can be machined away.
Can 1.2738 Nitrided be welded?
Not readily — weldability is rated not recommended (10/100). Preheat to 250–325 °C before repair welding, use matching mould-steel filler at low current with multiple small passes, then temper immediately just below the original tempering temperature to restore hardness and prevent cracking.
What surface finishes work on 1.2738 Nitrided?
Polishes to a mirror finish and suits chemical texturing/photo-etching. It rusts in service, so hard chrome, electroless nickel, nitriding or PVD is common, and idle tools should be coated with rust-preventive oil.
Can 1.2738 Nitrided be formed, bent or molded?
Not cold formed; stock is supplied hot-rolled or forged and quenched and tempered. If re-hardening is needed, austenitise at 850–880 °C, oil quench or pressurised gas quench, then temper twice at 550–620 °C.
What is the maximum service temperature of 1.2738 Nitrided?
1.2738 Nitrided is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1.2738 Annealed and 1.2738 Prehard?
Annealed is the default condition — pick soft annealed stock at =235 HB for blanks needing heavy roughing, cold work or deep-hole drilling before through hardening and tempering; as-delivered strength and wear resistance are low. Prehard: use the standard 28–34 HRC (290–330 HB) pre-hardened delivery to cut cavities and go straight into production with no further heat treatment and no quench distortion risk. Yield strength is 470 MPa in Annealed versus 860 MPa in Prehard.
Can FabDigit make parts in 1.2738 Nitrided?
Yes — 1.2738 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
- EN ISO 4957 Tool steels — ISO/CEN (2018)
- GB/T 1299 / 3Cr2MnNiMo (718) — SAC (2014)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
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.