Steel 15MnVB-HR (Hot rolled)
Supply condition
GB 15MnVB
Cheapest mill condition for stock that will be re-heat-treated after machining.
Values for the HR condition
Other 15MnVB tempers and conditions
15MnVB is listed in 8 conditions; see the grade overview at 15MnVB.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard GB/T 3077 delivery condition — softest, best for machining before carburizing or quench-tempering. | 390 | 620 | 22 | 187 HB | — |
HRThis page Hot rolled | Cheapest mill condition for stock that will be re-heat-treated after machining. | 440 | 680 | 18 | 13 HRC | 7.8 % IACS |
Normalized | Uniform fine-grain structure with better toughness than as-rolled; common pre-treatment before carburizing. | 470 | 720 | 19 | 16 HRC | 7.8 % IACS |
Cold drawn | Close tolerance, bright finish bar for fastener heading and automatic-lathe parts. | 600 | 730 | 12 | 17 HRC | 7.7 % IACS |
quench + temper for property class 8.8 fasteners | Bolt heat treatment (oil quench + ~500–560 °C temper) meeting ISO 898-1 / GB/T 3098.1 class 8.8. | 720 | 900 | 14 | 28 HRC | — |
860 °C oil quench + 200 °C temper (GB/T 3077 spec condition) | Standard-specification high-strength condition for shafts and pins needing maximum strength with acceptable toughness. | 780 | 1,000 | 13 | 33 HRC | — |
Carburized and hardened | Pick for small/medium gears and splines needing a hard wear-resistant case over a tough Mn-V-B core. | 800 | 1,050 | 11 | 60 HRC | — |
quench + temper for property class 10.9 high-strength bolts | The classic Chinese use of 15MnVB: oil quench + ~420–480 °C temper for 10.9 structural bolts and connection sets. | 990 | 1,100 | 11 | 35 HRC | — |
What is 15MnVB-HR?
15MnVB-HR is 15MnVB supplied in the HR condition — cheapest mill condition for stock that will be re-heat-treated after machining. 15MnVB-HR has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 680 MPa (98.6 ksi) — stronger than 50% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi). 15MnVB-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). A is the default condition FabDigit quotes; HR is available on request or by drawing note.
15MnVB-HR properties
Typical room-temperature values for 15MnVB-HR; 23 are specific to this condition. Other listed values are 15MnVB reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
15MnVB-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical13
15MnVB-HR has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 680 MPa (98.6 ksi) — stronger than 50% of steel grades. Elongation at break is 18% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
15MnVB-HR is rated for continuous service to 350°C (662 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
15MnVB-HR conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 15MnVB-HR takes about 28 MJ of energy and emits 2.1 kg of CO₂ — less than 56% of steel grades. Typical recycled content is 25%.
Manufacturability8
15MnVB-HR's machinability is fair (50/100, worse than 53% of steel grades); weldability fair (50/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 15MnVB-HR
Is 15MnVB easy to machine?
Machine in the annealed ≤207 HB condition with carbide tooling; the Mn-V structure is gummy at low hardness, so use positive rake, generous feed and coolant, and finish-grind after hardening.
Can 15MnVB be welded?
Weldable with low-hydrogen electrodes but boron plus ~1.4 % Mn gives CE≈0.5–0.6 — preheat 150–250 °C, control interpass, and post-weld temper; avoid welding in the quenched-and-tempered fastener condition.
Can 15MnVB be formed, bent or molded?
Good hot forgeability at 1100–850 °C and adequate cold heading in the spheroidize-annealed state; avoid austenitizing above ~900 °C, which coarsens grain and kills the boron effect.
What surface finishes work on 15MnVB?
No corrosion resistance of its own — protect with zinc plating (bake to avoid hydrogen embrittlement above 1000 MPa), phosphate + oil, Dacromet/zinc-flake, or paint; not anodizable.
15MnVB 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 | 0.12 – 0.18 | 0.15 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 1.2 – 1.6 | 1.4 |
| Vgrain refiner | 0.07 – 0.12 | 0.09 |
| Bhardenability booster; requires Ti/Al N-fixing | 5×10⁻⁴ – 0 | 0 |
| Crresidual | ≤ 0.3 | — |
| Niresidual | ≤ 0.3 | — |
| Curesidual | ≤ 0.25 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
15MnVB-HR — frequently asked
What is 15MnVB-HR used for?
15MnVB-HR is typically used for small gears, shafts and pins. In short: tough-core carburizing grade; service to 400 °C; most weldable boron gear steel.
What is the yield strength of 15MnVB-HR?
15MnVB-HR has a typical yield strength of 440 MPa (63.8 ksi) and a tensile strength of 680 MPa (98.6 ksi) — stronger than 50% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 15MnVB-HR easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machine in the annealed ≤207 HB condition with carbide tooling; the Mn-V structure is gummy at low hardness, so use positive rake, generous feed and coolant, and finish-grind after hardening.
Can 15MnVB-HR be welded?
With care — weldability is rated fair (50/100). Weldable with low-hydrogen electrodes but boron plus ~1.4 % Mn gives CE≈0.5–0.6 — preheat 150–250 °C, control interpass, and post-weld temper; avoid welding in the quenched-and-tempered fastener condition.
What surface finishes work on 15MnVB-HR?
No corrosion resistance of its own — protect with zinc plating (bake to avoid hydrogen embrittlement above 1000 MPa), phosphate + oil, Dacromet/zinc-flake, or paint; not anodizable.
Can 15MnVB-HR be formed, bent or molded?
Good hot forgeability at 1100–850 °C and adequate cold heading in the spheroidize-annealed state; avoid austenitizing above ~900 °C, which coarsens grain and kills the boron effect.
What is the maximum service temperature of 15MnVB-HR?
15MnVB-HR is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 15MnVB-A and 15MnVB-QT109?
A is the default condition — standard GB/T 3077 delivery condition — softest, best for machining before carburizing or quench-tempering. QT109: the classic Chinese use of 15MnVB: oil quench + ~420–480 °C temper for 10.9 structural bolts and connection sets. Yield strength is 390 MPa in A versus 990 MPa in QT109.
Sources
- ISO 898-1 Mechanical properties of fasteners made of carbon steel and alloy steel — ISO (2013)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — 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.