Steel 15-WQT
Heat-treated state
WQT = 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.
Values for the WQT 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 |
|---|---|---|---|---|---|---|
HRDefault 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 | — |
WQTThis page 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-WQT?
15-WQT is 15 heat treated to WQT — thin sections only — gives a modest strength bump when carburizing is not wanted; hardenability is very low. 15-WQT has a yield strength of 400 MPa (58 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 60% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi). 15-WQT 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). HR is the default condition FabDigit quotes; WQT is available on request or by drawing note.
Advantages
- High electrical conductivity — 10.2 % IACS, better than 87% of steel grades
- Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
- Readily welded — 80/100, better than 79% of steel grades
Limitations
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
15-WQT properties
Typical room-temperature values for 15-WQT; 23 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-WQT 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-WQT has a yield strength of 400 MPa (58 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 60% of steel grades. Elongation at break is 20% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
15-WQT is rated for continuous service to 180°C (356 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
15-WQT conducts electricity at 10.2 % IACS, better than 87% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 15-WQT 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-WQT's machinability is good (55/100, better than 62% of steel grades); weldability very good (80/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 15-WQT
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-WQT — frequently asked
What is 15-WQT used for?
15-WQT 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-WQT?
15-WQT has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 15-WQT easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% 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-WQT be welded?
Yes — weldability is rated very good (80/100). 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-WQT?
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-WQT 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-WQT?
15-WQT 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 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.