Steel Q235A
GB Q235A
Q235A is the A-quality level of China's general-purpose carbon structural steel Q235 (GB/T 700), a plain low-carbon killed/semi-killed steel with a 235 MPa minimum yield and 370–500 MPa tensile strength.
Values for the HR condition
Q235A tempers and conditions
Q235A is supplied in 5 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Use when maximum ductility and lowest hardness are needed for deep forming, or to soften cold-worked stock. | 240 | 385 | 34 | 112 HB | 10.7 % IACS |
Normalized | Pick for thick plate or forgings needing uniform fine-grain structure and better toughness/ductility after hot work. | 250 | 410 | 31 | 121 HB | 10.5 % IACS |
HRDefault Hot rolled | Default stock condition for plate, angle, channel, I-beam and hot-rolled coil in general welded structures. | 255 | 420 | 28 | 131 HB | — |
Cold rolled | Choose for thin gauge sheet parts needing tight thickness tolerance, flat clean surface and paint-ready finish. | 340 | 450 | 16 | 150 HB | 10.2 % IACS |
Cold drawn | Pick for shafts, pins and machined parts where higher yield, straightness and a bright as-drawn surface save machining. | 400 | 510 | 12 | 163 HB | — |
What is Q235A?
Q235A is the A-quality level of China's general-purpose carbon structural steel Q235 (GB/T 700), a plain low-carbon killed/semi-killed steel with a 235 MPa minimum yield and 370–500 MPa tensile strength. It is the default cheap structural steel for beams, plate, angle, channel, welded frames and general fabrication because it is highly weldable, formable and universally stocked. Grade A carries no guaranteed impact energy and the loosest S/P limits, so it should not be used for low-temperature, dynamically loaded or safety-critical welded joints (use Q235B/C/D instead), and its corrosion resistance is that of bare mild steel. Q235A has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,495°C (2,723 °F). Q235A has a yield strength of 255 MPa (37 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 93% of steel grades. Elongation at break is 28% and the elastic modulus is 206 GPa (29.9 Msi).
What is Q235A used for?
- Building frames and columns
- Structural beams, angle and channel
- Welded frames and skids
- Base plates and gussets
- Laser-cut sheet parts
- Enclosures, cabinets and machine guards
- Handrails and access platforms
Advantages
- Forms and bends easily — 82/100, better than 94% of steel grades
- Easy to machine — 65/100, better than 93% of steel grades
- Readily welded — 92/100, better than 93% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- High electrical conductivity — 10.5 % IACS, better than 89% of steel grades
Limitations
- Low strength — 255 MPa (37 ksi), worse than 93% 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
Q235A properties
Typical room-temperature values for Q235A-HR; bars are the position among steel grades.
Physical3
Q235A has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,495°C (2,723 °F).
Mechanical16
Q235A has a yield strength of 255 MPa (37 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 93% of steel grades. Elongation at break is 28% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
Q235A is rated for continuous service to 350°C (662 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
Q235A conducts electricity at 10.5 % IACS, better than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of Q235A takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 20%.
Manufacturability7
Q235A's machinability is good (65/100, better than 93% of steel grades); weldability excellent (92/100); formability very good (82/100).
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. Q235A is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Q235A
Is Q235A easy to machine?
Machines easily but gummy in the hot-rolled state — use positive-rake carbide, high speed and generous coolant; cold-drawn stock gives cleaner chips and better finish.
Can Q235A be welded?
Excellent weldability by SMAW/GMAW/SAW with E43xx (E4303/E4315) or ER70S-6, no preheat below ~30 mm; grade A's high S/P raises hot-cracking risk on thick restrained joints, so prefer Q235B for critical welds.
Can Q235A be formed, bent or molded?
Readily bent, rolled and press-formed cold at bend radii ≥1–1.5 t; hot forming 850–1050 °C, and avoid cold bending below 0 °C.
Manufacturability
The process limits FabDigit's quote engine applies to Q235A. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Better65 / 100 |
|---|---|
| ISO material group | P.1 |
| Cutting speed (rough / finish) | 220 / 260 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 | Excellent82 / 100 |
|---|---|
| Weldability | Excellent92 / 100 |
| Bendable | Yes |
Q235A 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, grade A | 0.14 – 0.22 | 0.18 |
| Si | ≤ 0.35 | 0.2 |
| Mntypically 0.30–0.65 in plate | ≤ 1.4 | 0.5 |
| P | ≤ 0.05 | 0.03 |
| Sloosest S limit of the Q235 quality grades | ≤ 0.05 | 0.03 |
| Fe | balance |
What surface finishes work on Q235A?
Must be protected — shot-blast then prime/paint, hot-dip galvanize or zinc-plate/phosphate; takes oil-blackening and powder coat well, but polished surfaces rust within hours.
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 Q235A cost?
Q235A 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.
Q235A — frequently asked
What is Q235A used for?
Q235A is typically used for building frames and columns, structural beams, angle and channel, welded frames and skids, base plates and gussets, laser-cut sheet parts and enclosures, cabinets and machine guards. In short: chinese mild-steel sheet.
What is the yield strength of Q235A?
Q235A has a typical yield strength of 255 MPa (37 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 93% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is Q235A easy to machine?
Reasonably — machinability is rated good (65/100, better than 93% of steel grades). Machines easily but gummy in the hot-rolled state — use positive-rake carbide, high speed and generous coolant; cold-drawn stock gives cleaner chips and better finish.
Can Q235A be welded?
Yes — weldability is rated excellent (92/100). Excellent weldability by SMAW/GMAW/SAW with E43xx (E4303/E4315) or ER70S-6, no preheat below ~30 mm; grade A's high S/P raises hot-cracking risk on thick restrained joints, so prefer Q235B for critical welds.
What surface finishes work on Q235A?
Must be protected — shot-blast then prime/paint, hot-dip galvanize or zinc-plate/phosphate; takes oil-blackening and powder coat well, but polished surfaces rust within hours.
Can Q235A be formed, bent or molded?
Readily bent, rolled and press-formed cold at bend radii ≥1–1.5 t; hot forming 850–1050 °C, and avoid cold bending below 0 °C.
What is the maximum service temperature of Q235A?
Q235A 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 Q235A-HR and Q235A-CD?
HR is the default condition — default stock condition for plate, angle, channel, I-beam and hot-rolled coil in general welded structures. CD: pick for shafts, pins and machined parts where higher yield, straightness and a bright as-drawn surface save machining. Yield strength is 255 MPa in HR versus 400 MPa in CD.
How much does Q235A cost?
Q235A 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 Q235A?
Yes — Q235A 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
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels — ASM International (1990)
- ASM Handbook Vol.19: Fatigue and Fracture — ASM International (1996)
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.