Steel Q275C
Grade
GB Q275
Q275C = quality level C
Choose for welded load-bearing parts working near 0 °C or with tighter P/S limits.
Values for the Q275C condition
Other Q275 tempers and conditions
Q275 is listed in 8 conditions; see the grade overview at Q275.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Use when maximum ductility, low residual stress or easier deep machining is more important than strength. | 255 | 430 | 28 | 128 HB | 10 % IACS |
Quality level A | Cheapest quality level; use for static, non-critical, above-zero-temperature parts. | 290 | 470 | 23 | 143 HB | 10 % IACS |
HRDefault Hot rolled | Default mill condition for plate, angle, channel, round bar and coil; pick it for general structural and machine-frame work. | 295 | 470 | 24 | 143 HB | 10 % IACS |
Quality level B | Most common quality level for welded structures at ambient temperature. | 295 | 470 | 24 | 143 HB | 10 % IACS |
Normalized | Choose for thick plate or forgings needing uniform fine grain and better toughness/consistency than as-rolled. | 300 | 490 | 26 | 148 HB | 10 % IACS |
Q275CThis page Quality level C | Choose for welded load-bearing parts working near 0 °C or with tighter P/S limits. | 300 | 470 | 24 | 143 HB | 10 % IACS |
Quality level D | Pick for cold-climate or dynamically loaded welded assemblies needing sub-zero toughness. | 300 | 470 | 25 | 143 HB | 10 % IACS |
Cold drawn | Pick for small-diameter shafting and pins needing close tolerance, bright surface and higher yield without heat treatment. | 460 | 580 | 11 | 175 HB | 9.5 % IACS |
What is Q275C?
Q275C is Q275 in the Q275C grade — choose for welded load-bearing parts working near 0 °C or with tighter P/S limits. Q275C has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 86% of steel grades. Elongation at break is 24% and the elastic modulus is 206 GPa (29.9 Msi). Q275C 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). HR is the default condition FabDigit quotes; Q275C is available on request or by drawing note.
Advantages
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
- Readily welded — 72/100, better than 75% of steel grades
Limitations
- Low strength — 300 MPa (43.5 ksi), worse than 86% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
- Low fracture toughness — 65 MPa·√m (59.2 ksi·√in), worse than 75% of steel grades
Q275C properties
Typical room-temperature values for Q275C; 23 are specific to this condition. Other listed values are Q275 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
Q275C 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
Q275C has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 86% of steel grades. Elongation at break is 24% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
Q275C is rated for continuous service to 350°C (662 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
Q275C conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of Q275C takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
Q275C's machinability is good (58/100, better than 75% of steel grades); weldability very good (72/100); formability good (58/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Q275C
Is Q275 easy to machine?
Machines like AISI 1030 at ~65 % of 1212; use carbide at 120–180 m/min with flood coolant — softer/gummier than alloy steel, so keep positive rake and sharp tools to avoid built-up edge.
Can Q275 be welded?
Weldable by SMAW/GMAW/SAW with E50xx (E5015/ER50-6) filler, but carbon equivalent ≈0.45 means preheat 100–150 °C above ~25 mm thickness and avoid rapid cooling to prevent HAZ hardening and cold cracking.
Can Q275 be formed, bent or molded?
Best hot formed at 900–1150 °C; cold bending needs a generous radius (≥2.5 t) and preferably annealed or normalized stock — springback and edge cracking are higher than with Q235.
What surface finishes work on Q275?
No corrosion resistance bare: shot-blast then prime/paint, hot-dip galvanize, zinc-plate or phosphate-and-oil; can be flame- or induction-hardened locally for wear surfaces.
Q275 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 700-2006: A ≤0.24, B ≤0.21, C/D ≤0.20 (older GB 700-88 allowed 0.28–0.38) | ≤ 0.24 | 0.21 |
| Si | ≤ 0.35 | 0.25 |
| Mn | ≤ 1.5 | 1 |
| PC ≤0.040, D ≤0.035 | ≤ 0.05 | 0.03 |
| SB ≤0.045, C ≤0.040, D ≤0.035 | ≤ 0.05 | 0.03 |
| Fe | balance | — |
Q275C — frequently asked
What is Q275C used for?
Q275C is typically used for machine frames and base plates, linkages and levers, plain shafting and axles, rail and track fittings, simple wear plates and guides and welded brackets and gussets. In short: workhorse Chinese plate.
What is the yield strength of Q275C?
Q275C has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 86% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is Q275C easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like AISI 1030 at ~65 % of 1212; use carbide at 120–180 m/min with flood coolant — softer/gummier than alloy steel, so keep positive rake and sharp tools to avoid built-up edge.
Can Q275C be welded?
Yes — weldability is rated very good (72/100). Weldable by SMAW/GMAW/SAW with E50xx (E5015/ER50-6) filler, but carbon equivalent ≈0.45 means preheat 100–150 °C above ~25 mm thickness and avoid rapid cooling to prevent HAZ hardening and cold cracking.
What surface finishes work on Q275C?
No corrosion resistance bare: shot-blast then prime/paint, hot-dip galvanize, zinc-plate or phosphate-and-oil; can be flame- or induction-hardened locally for wear surfaces.
Can Q275C be formed, bent or molded?
Best hot formed at 900–1150 °C; cold bending needs a generous radius (≥2.5 t) and preferably annealed or normalized stock — springback and edge cracking are higher than with Q235.
What is the maximum service temperature of Q275C?
Q275C is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Q275-HR and Q275-CD?
HR is the default condition — default mill condition for plate, angle, channel, round bar and coil; pick it for general structural and machine-frame work. CD: pick for small-diameter shafting and pins needing close tolerance, bright surface and higher yield without heat treatment. Yield strength is 295 MPa in HR versus 460 MPa in CD.
Can FabDigit make parts in Q275C?
Yes — Q275C is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- GB/T 700-2006 (Carbon structural steels) (2006)
- GB 50017 (design elastic constants) — MOHURD (2017)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 13 — Corrosion (galvanic series) — ASM International (1987)
- Mysteel / SMM hot-rolled plate & section price levels — Mysteel / SMM (2026)
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.