Steel 20CrMnTiB-A (Solution annealed)
Temper · default condition
GB 20CrMnTiB
Standard supply condition for gear blanks: uniform ferrite–pearlite structure, 156–207 HB, best green machinability before carburizing.
Values for the A condition
Other 20CrMnTiB tempers and conditions
20CrMnTiB is listed in 8 conditions; see the grade overview at 20CrMnTiB.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefaultThis page Solution annealed | Standard supply condition for gear blanks: uniform ferrite–pearlite structure, 156–207 HB, best green machinability before carburizing. | 400 | 620 | 22 | 179 HB | — |
Hot rolled | Cheapest mill condition for forging stock or parts that will be annealed/normalized before machining. | 450 | 700 | 18 | 17 HRC | — |
normalized and high-tempered (stress relieved) | Choose when normalized bar is too hard to machine but full annealing is not wanted; softens bainite and relieves residual stress. | 470 | 700 | 20 | 15 HRC | 8 % IACS |
Normalized | Use to refine forging structure and homogenise grain size before carburizing; harder and less machinable than annealed because boron promotes bainite on air cooling. | 520 | 780 | 17 | 20 HRC | — |
Cold drawn | Bright, close-tolerance small-diameter bar for automatic-lathe production of pins, shafts and small pinions. | 620 | 760 | 12 | 230 HB | — |
Q&T 28-34 HRC | Pick for large sections needing maximum core toughness under a carburized case, or for machinable high-strength shafts. | 800 | 980 | 15 | 31 HRC | — |
860 °C oil quench + 200 °C temper (standard test condition) | The GB acceptance heat treatment for this grade; also used for uncarburized high-strength shafts and heavily loaded fasteners. | 920 | 1,180 | 12 | 41 HRC | — |
Carburized and hardened | The functional service condition for gears: 0.8–2.0 mm effective case at 58–63 HRC over a boron-hardened core of 30–45 HRC. | 1,000 | 1,250 | 9 | 60 HRC | — |
What is 20CrMnTiB-A?
20CrMnTiB-A is 20CrMnTiB in the A temper — standard supply condition for gear blanks: uniform ferrite–pearlite structure, 156–207 HB, best green machinability before carburizing. 20CrMnTiB-A has a yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi). 20CrMnTiB-A 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).
Limitations
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
20CrMnTiB-A properties
Typical room-temperature values for 20CrMnTiB-A; 10 are specific to this condition. Other listed values are 20CrMnTiB reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
20CrMnTiB-A 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).
Mechanical13
20CrMnTiB-A has a yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20CrMnTiB-A is rated for continuous service to 200°C (392 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
20CrMnTiB-A conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental2
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 20CrMnTiB-A takes about 34 MJ of energy and emits 2.3 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
20CrMnTiB-A's machinability is good (58/100, better than 75% of steel grades); weldability fair (35/100); formability fair (50/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 20CrMnTiB-A
Is 20CrMnTiB easy to machine?
Machine in the isothermally annealed condition (156–207 HB) with coated carbide, 120–180 m/min turning and generous flood coolant; leave 0.15–0.3 mm grinding stock for post-carburizing finishing.
Can 20CrMnTiB be welded?
Only weld with care — preheat 200–300 °C, low-hydrogen consumables and immediate 550–650 °C stress relief; never weld after carburizing.
Can 20CrMnTiB be formed, bent or molded?
Forge at 1150–1200 °C finishing above 850 °C, then normalize or isothermally anneal; cold forming is limited to light coining or straightening.
What surface finishes work on 20CrMnTiB?
Grind or hard-turn after case hardening, shot peen tooth roots for fatigue life, and protect with phosphating, black oxide, oil or zinc plating (bake to avoid hydrogen embrittlement).
20CrMnTiB 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 |
| Mn | 0.8 – 1.1 | 0.95 |
| Cr | 1 – 1.3 | 1.15 |
| Tialso fixes free N so that boron stays in solution | 0.04 – 0.1 | 0.07 |
| Bhardenability booster; effective only as soluble B | 8×10⁻⁴ – 0 | 0 |
| Niresidual | ≤ 0.3 | — |
| Curesidual | ≤ 0.25 | — |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
20CrMnTiB-A — frequently asked
What is 20CrMnTiB-A used for?
20CrMnTiB-A is typically used for heavy truck gears, gearboxes and differential gears. In short: deep-case boron gear steel; highest hardenability in family; heavy-duty automotive gearing.
What is the yield strength of 20CrMnTiB-A?
20CrMnTiB-A has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 20CrMnTiB-A easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machine in the isothermally annealed condition (156–207 HB) with coated carbide, 120–180 m/min turning and generous flood coolant; leave 0.15–0.3 mm grinding stock for post-carburizing finishing.
Can 20CrMnTiB-A be welded?
With care — weldability is rated fair (35/100). Only weld with care — preheat 200–300 °C, low-hydrogen consumables and immediate 550–650 °C stress relief; never weld after carburizing.
What surface finishes work on 20CrMnTiB-A?
Grind or hard-turn after case hardening, shot peen tooth roots for fatigue life, and protect with phosphating, black oxide, oil or zinc plating (bake to avoid hydrogen embrittlement).
Can 20CrMnTiB-A be formed, bent or molded?
Forge at 1150–1200 °C finishing above 850 °C, then normalize or isothermally anneal; cold forming is limited to light coining or straightening.
What is the maximum service temperature of 20CrMnTiB-A?
20CrMnTiB-A 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 20CrMnTiB-A and 20CrMnTiB-CH?
A is the default condition — standard supply condition for gear blanks: uniform ferrite–pearlite structure, 156–207 HB, best green machinability before carburizing. CH: the functional service condition for gears: 0.8–2.0 mm effective case at 58–63 HRC over a boron-hardened core of 30–45 HRC. Yield strength is 400 MPa in A versus 1,000 MPa in CH.
Sources
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (carburizing, boron 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.