Steel 20MnTiB-CH (Carburized and hardened)
Heat-treated state
GB 20MnTiB
The production condition for gears: 0.6–1.4 mm hardened case at 58–62 HRC over a 30–40 HRC tough core.
Values for the CH condition
Other 20MnTiB tempers and conditions
20MnTiB is listed in 7 conditions; see the grade overview at 20MnTiB.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard delivery condition for gear-blank bar: soft, uniform structure for hobbing and shaping before carburizing. | 380 | 620 | 22 | 170 HB | — |
Hot rolled | Mill as-rolled bar; hardness scatter is high, normally re-annealed or normalized before machining. | 430 | 700 | 18 | 14 HRC | 8 % IACS |
Normalized | Choose to homogenize forgings and refine grain before carburizing when distortion control matters. | 450 | 700 | 19 | 14 HRC | 8 % IACS |
Cold drawn | Pick for close-tolerance bright bar used on automatics; strength up, ductility down versus annealed. | 620 | 750 | 11 | 18 HRC | 8 % IACS |
oil quenched + tempered ≈450 °C (medium-hardness through-hardened) | Use where toughness and machinability matter more than peak strength, e.g. shafts and links that are not carburized. | 780 | 950 | 15 | 30 HRC | — |
CHThis page Carburized and hardened | The production condition for gears: 0.6–1.4 mm hardened case at 58–62 HRC over a 30–40 HRC tough core. | 950 | 1,200 | 10 | 60 HRC | — |
oil quenched 860 °C + tempered 200 °C (GB/T 3077 test condition) | The specification heat treatment used for acceptance testing; also used for through-hardened high-strength shafts and fasteners. | 980 | 1,180 | 12 | 38 HRC | — |
What is 20MnTiB-CH?
20MnTiB-CH is 20MnTiB heat treated to CH — the production condition for gears: 0.6–1.4 mm hardened case at 58–62 HRC over a 30–40 HRC tough core. 20MnTiB-CH has a yield strength of 950 MPa (138 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 91% of steel grades. Elongation at break is 10% and the elastic modulus is 210 GPa (30.5 Msi). 20MnTiB-CH 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). A is the default condition FabDigit quotes; CH is available on request or by drawing note.
Advantages
- High strength — 950 MPa (138 ksi), better than 91% of steel grades
Limitations
- Difficult to weld — 5/100, worse than 100% of steel grades
- Difficult to machine — 10/100, worse than 99% of steel grades
- Limited formability — 3/100, worse than 99% of steel grades
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
20MnTiB-CH properties
Typical room-temperature values for 20MnTiB-CH; 13 are specific to this condition. Other listed values are 20MnTiB reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
20MnTiB-CH 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).
Mechanical13
20MnTiB-CH has a yield strength of 950 MPa (138 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 91% of steel grades. Elongation at break is 10% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20MnTiB-CH is rated for continuous service to 180°C (356 °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 µm/m·K (6.67 µin/in·°F).
Electrical3
20MnTiB-CH conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 20MnTiB-CH takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
20MnTiB-CH's machinability is not recommended (10/100, worse than 99% of steel grades); weldability not recommended (5/100); formability not recommended (3/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 20MnTiB-CH
Is 20MnTiB easy to machine?
Machine in the annealed (≤187 HB) or normalized state with coated carbide; sticky low-carbon chips need positive rake and good coolant — machinability roughly 55–60 % of 1212.
Can 20MnTiB be welded?
Poor to fair: carbon equivalent ~0.6 with boron, so use low-hydrogen consumables, 150–250 °C preheat and immediate stress relief; never weld after carburizing.
Can 20MnTiB be formed, bent or molded?
Hot forge 1150–850 °C then normalize/anneal; cold heading and moderate cold forming are practical only in the spheroidize-annealed condition.
What surface finishes work on 20MnTiB?
No corrosion resistance — protect with phosphate + oil, zinc or manganese phosphate; gear flanks are usually shot-peened and ground after carburizing, and plating must avoid hydrogen embrittlement (bake 190–220 °C).
20MnTiB 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 – 0.24 | 0.2 |
| Si | 0.17 – 0.37 | 0.27 |
| Mnmain hardenability element | 1.3 – 1.6 | 1.45 |
| Tifixes N, refines austenite grain, protects boron | 0.04 – 0.1 | 0.07 |
| Bhardenability booster | 5×10⁻⁴ – 0 | 0 |
| Crresidual | ≤ 0.3 | — |
| Niresidual | ≤ 0.3 | — |
| Curesidual | ≤ 0.3 | — |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
20MnTiB-CH — frequently asked
What is 20MnTiB-CH used for?
20MnTiB-CH is typically used for truck gears, tractor gears and carburized shafts. In short: titanium-refined carburizing steel; truck and tractor gear grade; fair weldability at best.
What is the yield strength of 20MnTiB-CH?
20MnTiB-CH has a typical yield strength of 950 MPa (138 ksi) and a tensile strength of 1,200 MPa (174 ksi) — stronger than 91% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 20MnTiB-CH easy to machine?
Not especially — machinability is rated not recommended (10/100, worse than 99% of steel grades). Machine in the annealed (≤187 HB) or normalized state with coated carbide; sticky low-carbon chips need positive rake and good coolant — machinability roughly 55–60 % of 1212.
Can 20MnTiB-CH be welded?
Not readily — weldability is rated not recommended (5/100). Poor to fair: carbon equivalent ~0.6 with boron, so use low-hydrogen consumables, 150–250 °C preheat and immediate stress relief; never weld after carburizing.
What surface finishes work on 20MnTiB-CH?
No corrosion resistance — protect with phosphate + oil, zinc or manganese phosphate; gear flanks are usually shot-peened and ground after carburizing, and plating must avoid hydrogen embrittlement (bake 190–220 °C).
Can 20MnTiB-CH be formed, bent or molded?
Hot forge 1150–850 °C then normalize/anneal; cold heading and moderate cold forming are practical only in the spheroidize-annealed condition.
What is the maximum service temperature of 20MnTiB-CH?
20MnTiB-CH is rated for continuous use to about 180°C (356 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 20MnTiB-A and 20MnTiB-QT200?
A is the default condition — standard delivery condition for gear-blank bar: soft, uniform structure for hobbing and shaping before carburizing. QT200: the specification heat treatment used for acceptance testing; also used for through-hardened high-strength shafts and fasteners. Yield strength is 380 MPa in A versus 980 MPa in QT200.
Sources
- GB/T 3077 (Alloy structural steels) (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (boron steels, carburizing) — 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.