Steel 50B60-HR (Hot rolled)
Supply condition
EN 50B60 · UNS G50601
Lowest-cost mill condition for parts that will be fully heat treated after rough machining or forging.
Values for the HR condition
Other 50B60 tempers and conditions
50B60 is listed in 10 conditions; see the grade overview at 50B60.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose for cold-headed fasteners or deep cold upsetting before hardening; lowest hardness and best cold ductility. | 400 | 690 | 22 | 11 HRC | 8.8 % IACS |
ADefault Solution annealed | Standard stock condition for bar that will be machined and then quenched and tempered by the user. | 420 | 750 | 16 | 217 HB | — |
HRThis page Hot rolled | Lowest-cost mill condition for parts that will be fully heat treated after rough machining or forging. | 530 | 880 | 12 | 25 HRC | 8.6 % IACS |
Normalized | Used to homogenize forgings and refine grain before hardening; note that boron steels air-harden appreciably. | 620 | 1,000 | 11 | 30 HRC | 8.5 % IACS |
Cold drawn | Pick for close-tolerance, bright-surface bar going straight to machining; higher strength but residual stresses and reduced ductility. | 700 | 830 | 10 | 23 HRC | — |
Q&T | Softest quenched-and-tempered condition; used where machining after heat treatment and maximum ductility are needed. | 830 | 930 | 18 | 28 HRC | — |
Q&T | Tough through-hardened condition for shafts, links and machinery parts needing impact capability. | 1,050 | 1,160 | 14 | 36 HRC | — |
Q&T | Classic leaf-spring / torsion-bar condition balancing high elastic limit with usable toughness. | 1,350 | 1,450 | 11 | 44 HRC | — |
Q&T | High-hardness spring and wear condition; avoid 260–370 °C for impact-critical parts (temper embrittlement range). | 1,650 | 1,790 | 9 | 52 HRC | — |
Q&T | Maximum hardness and wear resistance for cutting edges and abrasion parts; very low toughness, brittle in impact. | 1,780 | 2,000 | 8 | 57 HRC | — |
What is 50B60-HR?
50B60-HR is 50B60 supplied in the HR condition — lowest-cost mill condition for parts that will be fully heat treated after rough machining or forging. 50B60-HR has a yield strength of 530 MPa (76.9 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 69% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). 50B60-HR 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; HR is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
Limitations
- Low fracture toughness — 48 MPa·√m (43.7 ksi·√in), worse than 88% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Difficult to weld — 22/100, worse than 81% of steel grades
- Difficult to machine — 38/100, worse than 80% of steel grades
50B60-HR properties
Typical room-temperature values for 50B60-HR; 22 are specific to this condition. Other listed values are 50B60 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
50B60-HR 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
50B60-HR has a yield strength of 530 MPa (76.9 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 69% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
50B60-HR 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
50B60-HR conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 50B60-HR takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
50B60-HR's machinability is fair (38/100, worse than 80% of steel grades); weldability poor (22/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 50B60-HR
Is 50B60 easy to machine?
Machine in the annealed or spheroidized state (~60 % of 1212); use rigid setups, carbide tooling and moderate speeds — hardness above 40 HRC needs ceramic/CBN or grinding.
Can 50B60 be welded?
Poor weldability (CE ≈ 0.9): preheat 250–350 °C, low-hydrogen consumables, immediate post-weld temper; avoid welding on finished springs.
Can 50B60 be formed, bent or molded?
Hot form or forge at 1050–1200 °C; cold bending only after spheroidize annealing, otherwise expect cracking and heavy springback.
What surface finishes work on 50B60?
No natural corrosion resistance — shot peen springs for fatigue life, then phosphate + oil, zinc or Zn-Ni plate (bake 190 °C for hydrogen relief above 40 HRC) or paint.
50B60 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 | 0.56 – 0.64 | 0.6 |
| Mn | 0.75 – 1 | 0.88 |
| Si | 0.15 – 0.35 | 0.25 |
| Cr | 0.4 – 0.6 | 0.5 |
| Bhardenability booster; requires Ti/Al nitrogen fixing | 5×10⁻⁴ – 0 | 0 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
50B60-HR — frequently asked
What is 50B60-HR used for?
50B60-HR is typically used for coil and leaf springs, high-strength bolts and clutch discs. In short: deep-hardening spring steel; higher carbon than 50B50; poor weldability by design.
What is the yield strength of 50B60-HR?
50B60-HR has a typical yield strength of 530 MPa (76.9 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 69% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 50B60-HR easy to machine?
Not especially — machinability is rated fair (38/100, worse than 80% of steel grades). Machine in the annealed or spheroidized state (~60 % of 1212); use rigid setups, carbide tooling and moderate speeds — hardness above 40 HRC needs ceramic/CBN or grinding.
Can 50B60-HR be welded?
Not readily — weldability is rated poor (22/100). Poor weldability (CE ≈ 0.9): preheat 250–350 °C, low-hydrogen consumables, immediate post-weld temper; avoid welding on finished springs.
What surface finishes work on 50B60-HR?
No natural corrosion resistance — shot peen springs for fatigue life, then phosphate + oil, zinc or Zn-Ni plate (bake 190 °C for hydrogen relief above 40 HRC) or paint.
Can 50B60-HR be formed, bent or molded?
Hot form or forge at 1050–1200 °C; cold bending only after spheroidize annealing, otherwise expect cracking and heavy springback.
What is the maximum service temperature of 50B60-HR?
50B60-HR 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 50B60-A and 50B60-QT205?
A is the default condition — standard stock condition for bar that will be machined and then quenched and tempered by the user. QT205: maximum hardness and wear resistance for cutting edges and abrasion parts; very low toughness, brittle in impact. Yield strength is 420 MPa in A versus 1,780 MPa in QT205.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J1268 — Hardenability Bands for Boron H-Steels — SAE International (2018)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating — ASM International (1991)
- Low-alloy boron steel property tables (typical Q&T curves) — FabDigit internal compilation (2025)
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.