Steel 1.2738
EN 1.2738
1.2738 is a low-alloy CrMnMoNi plastic mould steel — P20 (1.2311) with roughly 1% nickel added — supplied prehardened by quench and temper at about 28–34 HRC (290–330 HB).
Values for the Annealed condition
1.2738 tempers and conditions
1.2738 is supplied in 7 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
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 | — |
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?
1.2738 is a low-alloy CrMnMoNi plastic mould steel — P20 (1.2311) with roughly 1% nickel added — supplied prehardened by quench and temper at about 28–34 HRC (290–330 HB). It is machined and used without further heat treatment, avoiding hardening distortion; the nickel raises hardenability so core hardness stays uniform in plates over 600 mm thick, and the steel polishes and photo-etches well and accepts nitriding and hardfacing repair. Limits are no corrosion resistance (protect from rust, not for halogen-bearing resins), moderate thermal conductivity, and a 34 HRC ceiling, so wear resistance is below hardened cold- or hot-work steels. 1.2738 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). 1.2738 has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 57% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi).
What is 1.2738 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
- Blow mould bodies
- Nitrided high-wear mould components
Advantages
- Polishes to a fine finish — 78/100, better than 95% of steel grades
- Easy to machine — 65/100, better than 93% of steel grades
Limitations
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades
1.2738 properties
Typical room-temperature values for 1.2738-Annealed; bars are the position among steel grades.
Physical3
1.2738 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 has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 57% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
1.2738 is rated for continuous service to 400°C (752 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades. Thermal expansion is 12.4 µm/m·K (6.89 µin/in·°F).
Electrical3
1.2738 conducts electricity at 7 % IACS, worse than 74% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 1.2738 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's machinability is good (65/100, better than 93% of steel grades); weldability fair (50/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 1.2738 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 1.2738
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.
Manufacturability
The process limits FabDigit applies to 1.2738. Every 1.2738 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better65 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
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 |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
How much does 1.2738 cost?
1.2738 is a standard-cost steel ($$), cheaper than about 59% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
1.2738 — frequently asked
What is 1.2738 used for?
1.2738 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?
1.2738 has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 57% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 1.2738 easy to machine?
Reasonably — machinability is rated good (65/100, better than 93% 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 be welded?
With care — weldability is rated fair (50/100). 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?
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 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?
1.2738 is rated for continuous use to about 400°C (752 °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.
How much does 1.2738 cost?
1.2738 is a standard-cost steel ($$), cheaper than about 59% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in 1.2738?
Yes — 1.2738 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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.