Steel 20MnVB
GB 20MnVB
20MnVB is a manganese-vanadium-boron alloy structural steel (GB/T 3077) in which boron raises hardenability and vanadium refines grain; it is stocked hot rolled, annealed, normalized, cold drawn, cold headed and quenched-and-tempered (QT200/QT400/QT550).
Reference datasheet — 20MnVB is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the QT200 condition
20MnVB tempers and conditions
20MnVB is supplied in 8 conditions, soft to hard. QT200 is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Soft condition for cold forming, machining of blanks and prior to carburizing. | 360 | 580 | 24 | 180 HB | — |
Hot rolled | Cheapest mill delivery form for forging, hot upsetting or subsequent heat treatment. | 430 | 680 | 20 | 200 HB | — |
Normalized | Uniform fine-grained structure for machining and as a pre-treatment before carburizing or Q&T. | 470 | 720 | 19 | 215 HB | — |
Cold drawn | Bright bar with close tolerance for shafts and fastener blanks needing no further sizing. | 620 | 750 | 12 | 20 HRC | 8 % IACS |
Oil quench + 550–600 °C temper | Tough quenched-and-tempered condition for machined shafts and structural parts where impact matters. | 680 | 830 | 18 | 26 HRC | — |
Oil quench + 400 °C temper | Medium-high strength with better ductility than low-temper for shafts and connecting parts. | 820 | 980 | 14 | 32 HRC | — |
Carburized and hardened | Primary gear condition: hard wear-resistant case (0.6–1.4 mm effective depth) over a tough 30–40 HRC core. | 900 | 1,150 | 10 | 60 HRC | — |
QT200Default 860 °C oil quench + 200 °C temper | Standard spec heat treatment giving maximum strength (Rm ≥1080 MPa) for highly loaded shafts and fasteners. | 950 | 1,150 | 12 | 38 HRC | — |
What is 20MnVB?
20MnVB is a manganese-vanadium-boron alloy structural steel (GB/T 3077) in which boron raises hardenability and vanadium refines grain; it is stocked hot rolled, annealed, normalized, cold drawn, cold headed and quenched-and-tempered (QT200/QT400/QT550). It is chosen for carburized and Q&T gears, shafts and gear rings, reaching 950 MPa yield, 1150 MPa tensile, 12 % elongation and 360 HB (38 HRC) in the default condition. Weldability and cold formability are poor (scores 35 and 20), there is no corrosion resistance bare, and service is limited to about 200 °C. 20CrMnTiB is the usual step up when a deeper carburized case is required. 20MnVB has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). 20MnVB has a yield strength of 950 MPa (138 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 91% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
What is 20MnVB used for?
- automotive gears
- shafts
- gear rings
Advantages
- High strength — 950 MPa (138 ksi), better than 91% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
- Difficult to machine — 38/100, worse than 80% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
20MnVB properties
Typical room-temperature values for 20MnVB-QT200; bars are the position among steel grades.
Physical3
20MnVB has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
20MnVB has a yield strength of 950 MPa (138 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 91% of steel grades. Elongation at break is 12% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20MnVB is rated for continuous service to 200°C (392 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
20MnVB conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 20MnVB takes about 28 MJ of energy and emits 2.1 kg of CO₂ — less than 56% of steel grades. Typical recycled content is 30%.
Manufacturability8
20MnVB's machinability is fair (38/100, worse than 80% of steel grades); weldability fair (35/100); formability poor (20/100).
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. 20MnVB is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 20MnVB
Is 20MnVB easy to machine?
Machine in the annealed or normalized state (≤207 HB) with coated carbide; after carburizing or low-temper Q&T only grinding/hard turning is practical.
Can 20MnVB be welded?
Weldable with care (CE ≈0.4): preheat 150–250 °C, low-hydrogen consumables and post-weld temper; boron increases hardenability so HAZ cracking risk is real — avoid welding carburized parts.
Can 20MnVB be formed, bent or molded?
Hot forge 1150–1200 °C, finish above 850 °C, slow cool then normalize/anneal; cold heading of fasteners requires spheroidize-annealed wire.
20MnVB 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 | 0.17 – 0.23 | 0.2 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 1.05 – 1.35 | 1.2 |
| Vgrain refiner / carbide former | 0.05 – 0.1 | 0.08 |
| Bhardenability booster; needs Ti/Al-fixed nitrogen | 5×10⁻⁴ – 0 | 0 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Crresidual max | ≤ 0.3 | |
| Niresidual max | ≤ 0.3 | |
| Curesidual max | ≤ 0.25 | |
| Fe | balance |
What surface finishes work on 20MnVB?
No corrosion resistance as-machined — use phosphating + oil, black oxide, zinc or Zn-Ni plating (bake to avoid hydrogen embrittlement above 1000 MPa); polishes well after hardening.
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).
Organic Coating
Black / Phosphate
Thermal Spray
How much does 20MnVB cost?
20MnVB is a budget-cost steel ($), cheaper than about 90% 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.
20MnVB — frequently asked
What is 20MnVB used for?
20MnVB is typically used for automotive gears, shafts and gear rings. In short: low-cost boron gear steel; high hardenability, low alloy; poor weldability, hard case.
What is the yield strength of 20MnVB?
20MnVB has a typical yield strength of 950 MPa (138 ksi) and a tensile strength of 1,150 MPa (167 ksi) — stronger than 91% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 20MnVB easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Machine in the annealed or normalized state (≤207 HB) with coated carbide; after carburizing or low-temper Q&T only grinding/hard turning is practical.
Can 20MnVB be welded?
With care — weldability is rated fair (35/100). Weldable with care (CE ≈0.4): preheat 150–250 °C, low-hydrogen consumables and post-weld temper; boron increases hardenability so HAZ cracking risk is real — avoid welding carburized parts.
What surface finishes work on 20MnVB?
No corrosion resistance as-machined — use phosphating + oil, black oxide, zinc or Zn-Ni plating (bake to avoid hydrogen embrittlement above 1000 MPa); polishes well after hardening.
Can 20MnVB be formed, bent or molded?
Hot forge 1150–1200 °C, finish above 850 °C, slow cool then normalize/anneal; cold heading of fasteners requires spheroidize-annealed wire.
What is the maximum service temperature of 20MnVB?
20MnVB is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 20MnVB-QT200 and 20MnVB-A?
QT200 is the default condition — standard spec heat treatment giving maximum strength (Rm ≥1080 MPa) for highly loaded shafts and fasteners. A: soft condition for cold forming, machining of blanks and prior to carburizing. Yield strength is 950 MPa in QT200 versus 360 MPa in A.
How much does 20MnVB cost?
20MnVB is a budget-cost steel ($), cheaper than about 90% 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.
Sources
- GB/T 3077 (Alloy structural steels) (2015)
- GB/T 699 / GB/T 702 bar dimensions and delivery conditions — SAC (2016)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook, 31st ed. (machinability and heat-treatment data) — Industrial Press (2020)
- (20MnVB/20CrMnTi ) — Mysteel / 1688 (2025)
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.