Steel Q275
GB Q275
Q275 is the highest-strength grade in China's GB/T 700 carbon structural steel family, supplied as hot-rolled plate, sections, bar and coil with a 275 MPa minimum yield and 410–540 MPa tensile range.
Values for the HR condition
Q275 tempers and conditions
Q275 is supplied in 8 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
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 |
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 Q275?
Q275 is the highest-strength grade in China's GB/T 700 carbon structural steel family, supplied as hot-rolled plate, sections, bar and coil with a 275 MPa minimum yield and 410–540 MPa tensile range. It is chosen where Q235 is not quite strong enough but low-alloy grades (Q345/Q355) are unnecessary or unavailable, typically for machine frames, linkages, shafting, rail fittings and simple wear parts. Its higher carbon and manganese reduce weldability and low-temperature toughness relative to Q235, so thick-section welds need preheat and only the C/D quality levels carry sub-zero impact guarantees. Q275 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). Q275 has a yield strength of 295 MPa (42.8 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 87% of steel grades. Elongation at break is 24% and the elastic modulus is 206 GPa (29.9 Msi).
What is Q275 used for?
- Machine frames and base plates
- Linkages and levers
- Plain shafting and axles
- Rail and track fittings
- Simple wear plates and guides
- Welded brackets and gussets
- General structural plate and sections
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
Limitations
- Low strength — 295 MPa (42.8 ksi), worse than 87% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 78% of steel grades
Q275 properties
Typical room-temperature values for Q275-HR; bars are the position among steel grades.
Physical3
Q275 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
Q275 has a yield strength of 295 MPa (42.8 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 87% of steel grades. Elongation at break is 24% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
Q275 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
Q275 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 Q275 takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
Q275's machinability is good (60/100, better than 83% of steel grades); weldability good (68/100); formability good (55/100).
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. Q275 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Q275
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.
Manufacturability
The process limits FabDigit applies to Q275. Every Q275 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better60 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Excellent55 / 100 |
|---|---|
| Weldability | Excellent68 / 100 |
| Bendable | Yes |
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 |
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.
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).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
How much does Q275 cost?
Q275 is a budget-cost steel ($), cheaper than about 99% 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.
Q275 — frequently asked
What is Q275 used for?
Q275 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 Q275?
Q275 has a typical yield strength of 295 MPa (42.8 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 87% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is Q275 easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% 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 Q275 be welded?
Yes — weldability is rated good (68/100). 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 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.
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 is the maximum service temperature of Q275?
Q275 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.
How much does Q275 cost?
Q275 is a budget-cost steel ($), cheaper than about 99% 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.
Can FabDigit make parts in Q275?
Yes — Q275 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; 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.