Steel 15
15 is a Chinese GB/T 699 quality carbon structural steel with about 0.12–0.19 % C, a close equivalent to SAE 1015, used both as a welded low-carbon steel and as a carburizing grade.
Reference datasheet — 15 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the HR condition
15 tempers and conditions
15 is supplied in 7 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
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 | — |
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 |
Supply forms, finishes and certifications
Ways 15 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
CHQ | Cold heading quality, spheroidize annealed wire | Surface finish |
What is 15?
15 is a Chinese GB/T 699 quality carbon structural steel with about 0.12–0.19 % C, a close equivalent to SAE 1015, used both as a welded low-carbon steel and as a carburizing grade. It is stocked hot-rolled, normalized, annealed, cold-drawn, cold-rolled, in cold-heading quality (CHQ), water-quenched-and-tempered and carburized conditions, as bar, wire and sheet. Default values are 245 MPa yield, 400 MPa tensile, 30 % elongation and 111 HB, with a machinability rating of 45. Core strength is low and the steel is gummy to cut and has no corrosion resistance; use 20 or SAE 1018/1020 where more core strength or better finish is needed. 15 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). 15 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).
What is 15 used for?
- carburized shafts
- bolts
- pins
- light structural components
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 properties
Typical room-temperature values for 15-HR; bars are the position among steel grades.
Physical3
15 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 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 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 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 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'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. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 15 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 15
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.
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 |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 15 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Other
- 1015
How much does 15 cost?
15 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
15 — frequently asked
What is 15 used for?
15 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?
15 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 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 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?
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 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?
15 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.
How much does 15 cost?
15 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.