Steel 15-HR (Hot rolled)
Supply condition · default condition
Cheapest, most-stocked condition for welded structures and parts that will be carburized or machined afterwards.
Values for the HR condition
Other 15 tempers and conditions
15 is listed in 7 conditions; see the grade overview at 15.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
HRDefaultThis page Hot rolled | Cheapest, most-stocked condition for welded structures and parts that will be carburized or machined afterwards. | 245 | 400 | 30 | 111 HB | — |
Cold rolled | Thin sheet and strip for stamped brackets, washers and deep-drawn cups needing a clean bright surface. | 260 | 380 | 30 | 115 HB | 10.8 % IACS |
Normalized | Standard GB/T 699 test condition; use for uniform fine grain, best toughness and predictable machining before carburizing. | 265 | 425 | 34 | 121 HB | — |
Solution annealed | Softest condition — pick it for maximum ductility in deep drawing or heavy cold forming. | 284 | 386 | 37 | 111 HB | — |
Cold drawn | Choose for bright straight bar with tight tolerance, higher yield and better chip control on automatic lathes. | 350 | 420 | 18 | 126 HB | — |
Carburized 900–930 °C, quenched + 180 °C temper | The main reason to use grade 15: hard wear-resistant case (58–62 HRC) over a tough, soft, unhardened core. | 350 | 500 | 15 | 60 HRC | — |
Water quenched (~900 °C) and tempered ~200 °C | Thin sections only — gives a modest strength bump when carburizing is not wanted; hardenability is very low. | 400 | 550 | 20 | 10 HRC | 10.2 % IACS |
What is 15-HR?
15-HR is 15 supplied in the HR condition — cheapest, most-stocked condition for welded structures and parts that will be carburized or machined afterwards. 15-HR has a yield strength of 245 MPa (35.5 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 95% of steel grades. Elongation at break is 30% and the elastic modulus is 205 GPa (29.7 Msi). 15-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,465°C (2,669 °F).
Advantages
- Readily welded — 96/100, better than 100% of steel grades
- Forms and bends easily — 85/100, better than 96% of steel grades
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
- Ductile — tolerates forming and impact — 30%, better than 93% of steel grades
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
Limitations
- Low strength — 245 MPa (35.5 ksi), worse than 95% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
15-HR properties
Typical room-temperature values for 15-HR; 11 are specific to this condition. Other listed values are 15 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
15-HR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,465°C (2,669 °F).
Mechanical16
15-HR has a yield strength of 245 MPa (35.5 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 95% of steel grades. Elongation at break is 30% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
15-HR is rated for continuous service to 400°C (752 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
15-HR conducts electricity at 10.8 % IACS, better than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 15-HR takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
15-HR's machinability is fair (45/100, worse than 65% of steel grades); weldability excellent (96/100); formability excellent (85/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 15-HR
Is 15 easy to machine?
Gummy and prone to built-up edge — run sharp positive-rake tools, high speed, generous coolant; normalizing or cold drawing before machining greatly improves surface finish.
Can 15 be welded?
Excellent — CE ≈ 0.25, weldable by SMAW/GMAW/TIG/spot with E43xx (E6013/E7018) filler, no preheat or PWHT required in normal thicknesses.
Can 15 be formed, bent or molded?
Very good cold formability: deep drawing, bending to tight radii (≈1t) and cold heading are all routine; hot forming at 850–1150 °C.
What surface finishes work on 15?
No natural corrosion protection — specify zinc/nickel plating, hot-dip galvanizing, phosphating, black oxide or paint; polishes only to a modest finish because of the soft ferrite matrix.
15 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 |
|---|---|---|
| CGB/T 699-2015 grade 15 | 0.12 – 0.19 | 0.15 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.35 – 0.65 | 0.5 |
| P≤0.030 for high-grade (A) quality | ≤ 0.04 | 0.02 |
| S≤0.030 for high-grade (A) quality | ≤ 0.04 | 0.02 |
| Crresidual | ≤ 0.25 | 0.1 |
| Niresidual | ≤ 0.3 | 0.1 |
| Curesidual | ≤ 0.25 | 0.1 |
| Fe | balance | — |
15-HR — frequently asked
What is 15-HR used for?
15-HR is typically used for carburized shafts, bolts, pins and light structural components. In short: carburizing-grade low-carbon steel; SAE 1015 equivalent; excellent cold-heading formability.
What is the yield strength of 15-HR?
15-HR has a typical yield strength of 245 MPa (35.5 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 95% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 15-HR easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Gummy and prone to built-up edge — run sharp positive-rake tools, high speed, generous coolant; normalizing or cold drawing before machining greatly improves surface finish.
Can 15-HR be welded?
Yes — weldability is rated excellent (96/100). Excellent — CE ≈ 0.25, weldable by SMAW/GMAW/TIG/spot with E43xx (E6013/E7018) filler, no preheat or PWHT required in normal thicknesses.
What surface finishes work on 15-HR?
No natural corrosion protection — specify zinc/nickel plating, hot-dip galvanizing, phosphating, black oxide or paint; polishes only to a modest finish because of the soft ferrite matrix.
Can 15-HR be formed, bent or molded?
Very good cold formability: deep drawing, bending to tight radii (≈1t) and cold heading are all routine; hot forming at 850–1150 °C.
What is the maximum service temperature of 15-HR?
15-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 15-HR and 15-WQT?
HR is the default condition — cheapest, most-stocked condition for welded structures and parts that will be carburized or machined afterwards. WQT: thin sections only — gives a modest strength bump when carburizing is not wanted; hardenability is very low. Yield strength is 245 MPa in HR versus 400 MPa in WQT.
Sources
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- SAE J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- 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.