Steel 15B62-HR (Hot rolled)
Supply condition · default condition
EN 15B62 · UNS G15621
Standard mill supply condition for bar and coil that will be formed and then quenched and tempered by the part maker.
Values for the HR condition
Other 15B62 tempers and conditions
15B62 is listed in 10 conditions; see the grade overview at 15B62.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Pick for cold heading of fastener blanks, deep machining or cold forming before hardening. | 420 | 700 | 22 | 200 HB | — |
HRDefaultThis page Hot rolled | Standard mill supply condition for bar and coil that will be formed and then quenched and tempered by the part maker. | 520 | 930 | 12 | 270 HB | — |
Normalized | Use to refine and homogenise structure after forging, before hardening or machining. | 570 | 1,000 | 11 | 30 HRC | 8 % IACS |
Cold drawn | Choose for close-tolerance bright bar and wire that needs straightness and higher as-supplied yield. | 730 | 860 | 10 | 24 HRC | 8 % IACS |
oil quenched, tempered ~575 °C | Tough medium-hardness setting for heavy-duty bolts, pins and shafts where impact matters more than peak strength. | 980 | 1,120 | 15 | 35 HRC | — |
oil quenched, tempered ~480 °C | Balanced spring/structural setting for leaf springs, clips, tillage tools and 10.9-class fasteners. | 1,250 | 1,400 | 10 | 43 HRC | — |
Austempered | Salt-bath bainitic route for thin springs and clips needing high strength with better ductility and less distortion than martensite + temper. | 1,250 | 1,500 | 11 | 45 HRC | 8 % IACS |
oil quenched, tempered ~400 °C (spring temper) | Classic spring condition — highest usable elastic limit for coil and leaf springs, spring clips and track components. | 1,450 | 1,620 | 8 | 48 HRC | — |
oil quenched, tempered ~300 °C | Wear-oriented setting for plough shares, cultivator points and cutting edges; low toughness, avoid shock and notches. | 1,650 | 1,900 | 6 | 53 HRC | — |
As-quenched | Intermediate condition only — boron gives near-full martensite in sections up to ~25 mm; must be tempered immediately. | 1,700 | 2,200 | 1 | 62 HRC | 7 % IACS |
What is 15B62-HR?
15B62-HR is 15B62 supplied in the HR condition — standard mill supply condition for bar and coil that will be formed and then quenched and tempered by the part maker. 15B62-HR has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 67% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). 15B62-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
Limitations
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 78% of steel grades
15B62-HR properties
Typical room-temperature values for 15B62-HR; 10 are specific to this condition. Other listed values are 15B62 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
15B62-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical15
15B62-HR has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 67% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
15B62-HR is rated for continuous service to 250°C (482 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
15B62-HR conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 15B62-HR takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 35%.
Manufacturability7
15B62-HR's machinability is fair (42/100, worse than 73% of steel grades); weldability poor (20/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 15B62-HR
Is 15B62 easy to machine?
Machine in the spheroidise-annealed condition with carbide tooling and rigid setups; above ~40 HRC switch to grinding, CBN or EDM.
Can 15B62 be welded?
Effectively unweldable as a structural joint — 0.60 % C plus boron gives crack-prone martensite; if unavoidable use low-hydrogen consumables, 250–350 °C preheat and immediate stress relief/temper.
Can 15B62 be formed, bent or molded?
Cold head or bend only in the annealed state with generous radii; otherwise hot form at 950–1150 °C and re-harden — do not austenitise above ~950 °C or boron hardenability drops.
What surface finishes work on 15B62?
Shot peen springs for fatigue life, then phosphate + oil, zinc or zinc-flake coating; bake at 190–220 °C within 4 h of electroplating to avoid hydrogen embrittlement.
15B62 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 |
|---|---|---|
| CSAE 15Bxx high-carbon grade | 0.54 – 0.67 | 0.6 |
| Mn | 1 – 1.3 | 1.15 |
| Si | 0.15 – 0.35 | 0.25 |
| Bhardenability booster; requires Ti/Al to fix free nitrogen | 5×10⁻⁴ – 0 | 0 |
| P | ≤ 0.03 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
15B62-HR — frequently asked
What is 15B62-HR used for?
15B62-HR is typically used for leaf springs, heavy fasteners and washers. In short: highest-carbon boron grade here; spring-capable through-hardening steel; lowest formability, 30/100.
What is the yield strength of 15B62-HR?
15B62-HR has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 15B62-HR easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Machine in the spheroidise-annealed condition with carbide tooling and rigid setups; above ~40 HRC switch to grinding, CBN or EDM.
Can 15B62-HR be welded?
Not readily — weldability is rated poor (20/100). Effectively unweldable as a structural joint — 0.60 % C plus boron gives crack-prone martensite; if unavoidable use low-hydrogen consumables, 250–350 °C preheat and immediate stress relief/temper.
What surface finishes work on 15B62-HR?
Shot peen springs for fatigue life, then phosphate + oil, zinc or zinc-flake coating; bake at 190–220 °C within 4 h of electroplating to avoid hydrogen embrittlement.
Can 15B62-HR be formed, bent or molded?
Cold head or bend only in the annealed state with generous radii; otherwise hot form at 950–1150 °C and re-harden — do not austenitise above ~950 °C or boron hardenability drops.
What is the maximum service temperature of 15B62-HR?
15B62-HR is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 15B62-HR and 15B62-AQ?
HR is the default condition — standard mill supply condition for bar and coil that will be formed and then quenched and tempered by the part maker. AQ: intermediate condition only — boron gives near-full martensite in sections up to ~25 mm; must be tempered immediately. Yield strength is 520 MPa in HR versus 1,700 MPa in AQ.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J403 / J1268 — Carbon and Alloy Steel Chemical Compositions and Hardenability Bands — SAE International (2019)
- 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 (boron steel hardenability) — ASM International (1991)
- ASM Handbook Vol. 16 — Machining — ASM International (1989)
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.