Steel Q275 · supply condition · default condition
Steel Q275-HR
Properties of the HR condition, compared with the other Q275 tempers.
Default mill condition for plate, angle, channel, round bar and coil; pick it for general structural and machine-frame work.
What is Q275-HR?
Q275-HR is Q275 supplied in the HR condition — default mill condition for plate, angle, channel, round bar and coil; pick it for general structural and machine-frame work. Q275-HR 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). Q275-HR 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).
Advantages
- Easy to machine — 60/100, better than 83% of steel grades
- High electrical conductivity — 10 % IACS, better than 82% 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 79% of steel grades
Q275-HR properties
Typical room-temperature values for Q275-HR — 8 properties are specific to this condition; the rest are grade-level values shared by every Q275 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
Q275-HR 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).
Mechanical15
Q275-HR 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-HR 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-HR conducts electricity at 10 % IACS, better than 82% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of Q275-HR 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-HR'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.
Other Q275 tempers and conditions
Q275 is also supplied in 7 other conditions. The full side-by-side table is on the Q275 overview.
- HRDefaultDefault mill condition for plate, angle, channel, round bar and coil; pick it for general structural and machine-frame work.295 MPa yield · 143 HB
- CDPick for small-diameter shafting and pins needing close tolerance, bright surface and higher yield without heat treatment.460 MPa yield · 175 HB
- NChoose for thick plate or forgings needing uniform fine grain and better toughness/consistency than as-rolled.300 MPa yield · 148 HB
Working with Q275-HR
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 | — |
Q275-HR — frequently asked
What is Q275-HR used for?
Q275-HR 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-HR?
Q275-HR 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-HR 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-HR 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-HR?
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-HR 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-HR?
Q275-HR 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 Q275-HR?
Yes — Q275-HR is available for CNC machining and sheet metal with instant online pricing. 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.