Steel 56Mn4 +QT-30HRC (+QT 28–32 HRC)
Heat-treated state
EN 56Mn4
Tough through-hardened condition for shafts and highly stressed machined parts.
Values for the +QT-30HRC condition
Other 56Mn4 tempers and conditions
56Mn4 is listed in 9 conditions; see the grade overview at 56Mn4.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Treated for high shearability | Choose for strip/blank that must be blanked, sheared or fine-punched with clean edges before hardening. | 380 | 650 | 17 | 195 HB | — |
+ADefault Annealed | Standard stock condition for machining, cold forming and as the starting state before hardening. | 400 | 690 | 15 | 205 HB | — |
Hot rolled | Cheapest bar/wire-rod condition when the part will be re-heat-treated anyway. | 470 | 830 | 12 | 24 HRC | — |
Normalized | Uniform fine pearlitic structure for consistent machining and predictable response to induction hardening. | 480 | 800 | 13 | 22 HRC | — |
Induction hardened | The main reason this grade exists: hard wear-resistant induction case on a tough core for bearing races, pins and gear teeth. | 600 | 900 | 10 | 60 HRC | — |
Cold drawn | Pick for close-tolerance bright bar with raised strength and good surface for turned/wear parts. | 700 | 850 | 8 | 25 HRC | — |
+QT-30HRCThis page +QT 28–32 HRC | Tough through-hardened condition for shafts and highly stressed machined parts. | 800 | 1,000 | 12 | 30 HRC | — |
+QT 38–42 HRC | Higher-strength through-hardened condition for wear-loaded links, cams and chain parts. | 1,080 | 1,280 | 9 | 40 HRC | — |
+QT 48–52 HRC | Maximum practical through-hardness for springs, blades and heavily worn small sections. | 1,450 | 1,700 | 6 | 50 HRC | — |
What is 56Mn4 +QT-30HRC?
56Mn4 +QT-30HRC is 56Mn4 heat treated to +QT-30HRC — tough through-hardened condition for shafts and highly stressed machined parts. 56Mn4 +QT-30HRC has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Elongation at break is 12% and the elastic modulus is 207 GPa (30 Msi). 56Mn4 +QT-30HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). +A is the default condition FabDigit quotes; +QT-30HRC is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High strength — 800 MPa (116 ksi), better than 86% of steel grades
Limitations
- Limited formability — 12/100, worse than 92% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Difficult to machine — 38/100, worse than 80% of steel grades
- Difficult to weld — 25/100, worse than 77% of steel grades
56Mn4 +QT-30HRC properties
Typical room-temperature values for 56Mn4 +QT-30HRC; 15 are specific to this condition. Other listed values are 56Mn4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
56Mn4 +QT-30HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
56Mn4 +QT-30HRC has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Elongation at break is 12% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
56Mn4 +QT-30HRC is rated for continuous service to 400°C (752 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
56Mn4 +QT-30HRC conducts electricity at 8.5 % IACS, better than 63% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 56Mn4 +QT-30HRC takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability8
56Mn4 +QT-30HRC's machinability is fair (38/100, worse than 80% of steel grades); weldability poor (25/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 56Mn4 +QT-30HRC
Is 56Mn4 easy to machine?
Machine in the +A/+S condition with carbide inserts, ~120–180 m/min; above ~35 HRC switch to CBN or grinding.
Can 56Mn4 be welded?
Poor weldability (CE ≈ 0.75–0.8): preheat 250–350 °C, low-hydrogen consumables and immediate stress relief/temper, or avoid welding altogether.
Can 56Mn4 be formed, bent or molded?
Cold blank, shear and lightly bend only in +A/+S strip with generous radii (≥2t); hot form 850–1100 °C, then slow-cool or normalize before hardening.
What surface finishes work on 56Mn4?
No anodizing — protect with zinc/manganese phosphate + oil, black oxide, zinc or hard-chrome plating; hardened surfaces polish and grind well but rust quickly unbare.
56Mn4 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 | 0.52 – 0.6 | 0.56 |
| Sisome strip specs allow ≤0.40 only | 0.15 – 0.4 | 0.25 |
| Mn | 0.9 – 1.2 | 1.05 |
| Pmax; 0.025 for cold-rolled strip (EN 10132-4) | ≤ 0.04 | 0.02 |
| Smax; 0.025 for cold-rolled strip | ≤ 0.04 | 0.02 |
| Crresidual | ≤ 0.4 | 0.1 |
| Niresidual | ≤ 0.4 | 0.1 |
| Moresidual | ≤ 0.1 | 0.03 |
| Curesidual | ≤ 0.3 | 0.15 |
| Fe | balance | — |
56Mn4 +QT-30HRC — frequently asked
What is 56Mn4 +QT-30HRC used for?
56Mn4 +QT-30HRC is typically used for bearing races, induction-hardened shafts, rollers and wear bushings. In short: deeper hardenability than 1045; induction-hardening wear grade; poor weldability, no corrosion resistance.
What is the yield strength of 56Mn4 +QT-30HRC?
56Mn4 +QT-30HRC has a typical yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 56Mn4 +QT-30HRC easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Machine in the +A/+S condition with carbide inserts, ~120–180 m/min; above ~35 HRC switch to CBN or grinding.
Can 56Mn4 +QT-30HRC be welded?
Not readily — weldability is rated poor (25/100). Poor weldability (CE ≈ 0.75–0.8): preheat 250–350 °C, low-hydrogen consumables and immediate stress relief/temper, or avoid welding altogether.
What surface finishes work on 56Mn4 +QT-30HRC?
No anodizing — protect with zinc/manganese phosphate + oil, black oxide, zinc or hard-chrome plating; hardened surfaces polish and grind well but rust quickly unbare.
Can 56Mn4 +QT-30HRC be formed, bent or molded?
Cold blank, shear and lightly bend only in +A/+S strip with generous radii (≥2t); hot form 850–1100 °C, then slow-cool or normalize before hardening.
What is the maximum service temperature of 56Mn4 +QT-30HRC?
56Mn4 +QT-30HRC 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 56Mn4 +A and 56Mn4-IH?
+A is the default condition — standard stock condition for machining, cold forming and as the starting state before hardening. IH: the main reason this grade exists: hard wear-resistant induction case on a tough core for bearing races, pins and gear teeth. Yield strength is 400 MPa in +A versus 600 MPa in IH.
Sources
- EN 10083-2 Steels for quenching and tempering — non-alloy steels — CEN (2006)
- EN 10132-4 Cold rolled narrow steel strip for heat treatment — spring and other applications — CEN (2000)
- SAE J403 / AISI 1552 chemical composition of carbon steels — SAE International (2014)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Stahlschlüssel (Key to Steel) — material 1.1233 — Verlag Stahlschlüssel Wegst (2019)
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.