Steel 5CrNiMo QT34-38
Heat-treated state
GB 5CrNiMo
QT34-38 = q&T 34–38 HRC
Choose the ~540 °C temper (34–38 HRC) for die blocks about 300–400 mm thick, balancing cavity wear resistance against resistance to gross cracking up to 480 °C.
Values for the QT34-38 condition
Other 5CrNiMo tempers and conditions
5CrNiMo is listed in 8 conditions; see the grade overview at 5CrNiMo.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault spheroidize/soft annealed forged block or bar | Order this soft annealed forged block or bar at 220 HB for rough machining the die cavity, then through-harden and temper the finished tool to its working hardness. | 450 | 760 | 18 | 220 HB | — |
850–870 °C air cool (pre-machining grain refinement) | Use 850–870 °C normalizing with air cooling after forging to refine structure and remove banding; it is normally followed by annealing rather than used as a delivered state. | 620 | 1,000 | 12 | 31 HRC | 6.6 % IACS |
untreated bar or block | Take the untreated as-rolled or as-forged blank for the lowest price and rough cut-off only; hardness is uneven near 320 HB, so anneal before any machining. | 680 | 1,050 | 12 | 34 HRC | 6.6 % IACS |
Q&T 30–34 HRC | Use the 560–580 °C temper at 30–34 HRC for blocks over about 400 mm thick and dovetail or holder sections, where 15% elongation and top toughness prevent through-cracking. | 880 | 1,050 | 15 | 32 HRC | — |
QT34-38This page Q&T 34–38 HRC | Choose the ~540 °C temper (34–38 HRC) for die blocks about 300–400 mm thick, balancing cavity wear resistance against resistance to gross cracking up to 480 °C. | 1,000 | 1,180 | 13 | 36 HRC | — |
Q&T 38–42 HRC | Pick the 490–520 °C temper at 38–42 HRC for hammer die blocks under about 300 mm thick, the common compromise between cavity wear resistance and toughness. | 1,120 | 1,300 | 11 | 40 HRC | — |
Q&T 44–48 HRC | Temper near 400 °C to 44–48 HRC for small hot-forging die inserts and punches where wear dominates and impact is light; elongation drops to 8% and service caps at 350 °C. | 1,300 | 1,500 | 8 | 46 HRC | — |
As-quenched | Use only as the specified hardenability check after 830–860 °C oil quenching at 55 HRC; temper immediately, since untempered blocks are brittle and crack-prone. | 1,520 | 1,980 | 2 | 55 HRC | 5.7 % IACS |
What is 5CrNiMo QT34-38?
5CrNiMo QT34-38 is 5CrNiMo heat treated to QT34-38 — choose the ~540 °C temper (34–38 HRC) for die blocks about 300–400 mm thick, balancing cavity wear resistance against resistance to gross cracking up to 480 °C. 5CrNiMo QT34-38 has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,180 MPa (171 ksi) — stronger than 92% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi). 5CrNiMo QT34-38 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; QT34-38 is available on request or by drawing note.
Advantages
- High strength — 1,000 MPa (145 ksi), better than 92% of steel grades
- High service temperature — 480°C (896 °F), better than 88% of steel grades
Limitations
- Difficult to machine — 28/100, worse than 91% of steel grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
5CrNiMo QT34-38 properties
Typical room-temperature values for 5CrNiMo QT34-38; 13 are specific to this condition. Other listed values are 5CrNiMo reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
5CrNiMo QT34-38 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).
Mechanical12
5CrNiMo QT34-38 has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,180 MPa (171 ksi) — stronger than 92% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
5CrNiMo QT34-38 is rated for continuous service to 480°C (896 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical2
5CrNiMo QT34-38 has an electrical resistivity of 2.6×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 5CrNiMo QT34-38 takes about 32 MJ of energy and emits 2.4 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 30%.
Manufacturability6
5CrNiMo QT34-38's machinability is poor (28/100, worse than 91% of steel grades); weldability poor (30/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 5CrNiMo QT34-38
Is 5CrNiMo easy to machine?
Rough the cavity in the annealed condition (≤241 HB) with coated carbide milling — this is the most economical route. After quench and temper to 34–42 HRC, restrict work to finishing passes with rigid clamping and low feed to avoid edge chipping.
Can 5CrNiMo be welded?
Weldability is poor. For cavity repair, preheat to 350–400 °C, use matching or H13-type electrodes, then temper immediately at about 20–30 °C below the original tempering temperature and cool slowly to prevent cracking.
Can 5CrNiMo be formed, bent or molded?
Cold forming is essentially impossible. Forge at 1050–1150 °C with finish forging not below about 850 °C, cool slowly after forging and anneal promptly to avoid flakes and cracks.
What surface finishes work on 5CrNiMo?
Cavities can be polished up to pre-mirror grades. Nitriding or boronizing is common to raise hot wear life, but an over-thick nitrided layer tends to spall under hammer loading; oil parts for storage and shipment to prevent rust.
5CrNiMo 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 | 0.5 – 0.6 | 0.55 |
| Si | 0.1 – 0.4 | 0.25 |
| Mn | 0.5 – 0.8 | 0.65 |
| Cr | 0.5 – 0.8 | 0.65 |
| Ni | 1.4 – 1.8 | 1.6 |
| Mo | 0.15 – 0.3 | 0.22 |
| Pimpurity limit | ≤ 0.03 | — |
| Simpurity limit | ≤ 0.03 | — |
| Fe | balance | — |
5CrNiMo QT34-38 — frequently asked
What is 5CrNiMo QT34-38 used for?
5CrNiMo QT34-38 is typically used for large forging dies, hammer dies and die blocks. In short: toughest hot-work die steel; for large hammer dies; deep-hardening die block grade.
What is the yield strength of 5CrNiMo QT34-38?
5CrNiMo QT34-38 has a typical yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,180 MPa (171 ksi) — stronger than 92% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 5CrNiMo QT34-38 easy to machine?
Not especially — machinability is rated poor (28/100, worse than 91% of steel grades). Rough the cavity in the annealed condition (≤241 HB) with coated carbide milling — this is the most economical route. After quench and temper to 34–42 HRC, restrict work to finishing passes with rigid clamping and low feed to avoid edge chipping.
Can 5CrNiMo QT34-38 be welded?
Not readily — weldability is rated poor (30/100). Weldability is poor. For cavity repair, preheat to 350–400 °C, use matching or H13-type electrodes, then temper immediately at about 20–30 °C below the original tempering temperature and cool slowly to prevent cracking.
What surface finishes work on 5CrNiMo QT34-38?
Cavities can be polished up to pre-mirror grades. Nitriding or boronizing is common to raise hot wear life, but an over-thick nitrided layer tends to spall under hammer loading; oil parts for storage and shipment to prevent rust.
Can 5CrNiMo QT34-38 be formed, bent or molded?
Cold forming is essentially impossible. Forge at 1050–1150 °C with finish forging not below about 850 °C, cool slowly after forging and anneal promptly to avoid flakes and cracks.
What is the maximum service temperature of 5CrNiMo QT34-38?
5CrNiMo QT34-38 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.
What is the difference between 5CrNiMo Annealed and 5CrNiMo-Q?
Annealed is the default condition — order this soft annealed forged block or bar at 220 HB for rough machining the die cavity, then through-harden and temper the finished tool to its working hardness. Q: use only as the specified hardenability check after 830–860 °C oil quenching at 55 HRC; temper immediately, since untempered blocks are brittle and crack-prone. Yield strength is 450 MPa in Annealed versus 1,520 MPa in Q.
Sources
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (Tool Steels) — ASM International (1991)
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.