Steel Q235B-CR (Cold rolled)
Supply condition
GB Q235B · ASTM A36 · EN S235JR · JIS SS400
Pick for thin gauge (0.3–3 mm) parts needing a clean bright surface, tight thickness tolerance and good bend/stamping behaviour.
Values for the CR condition
Other Q235B tempers and conditions
Q235B is listed in 5 conditions; see the grade overview at Q235B.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Normalized | Specified for thick plate or pressure parts where uniform fine grain and better impact toughness are needed after hot forming. | 245 | 410 | 31 | 115 HB | 10.8 % IACS |
HRDefault Hot rolled | Default stock condition for structural plate, angle, channel, beam and hot-rolled coil; cheapest and most widely available. | 250 | 420 | 28 | 120 HB | — |
Hot rolled, pickled and oiled | Use when hot-rolled strength/price is wanted but mill scale must be gone for welding, painting or stamping. | 250 | 420 | 28 | 120 HB | 10.8 % IACS |
CRThis page Cold rolled | Pick for thin gauge (0.3–3 mm) parts needing a clean bright surface, tight thickness tolerance and good bend/stamping behaviour. | 280 | 420 | 26 | 130 HB | — |
Cold drawn | Pick for turned/machined shafts and fasteners where bright surface, straightness and higher yield strength are required. | 380 | 500 | 15 | 150 HB | — |
What is Q235B-CR?
Q235B-CR is Q235B supplied in the CR condition — pick for thin gauge (0.3–3 mm) parts needing a clean bright surface, tight thickness tolerance and good bend/stamping behaviour. Q235B-CR has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 90% of steel grades. Elongation at break is 26% and the elastic modulus is 206 GPa (29.9 Msi). Q235B-CR 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). HR is the default condition FabDigit quotes; CR is available on request or by drawing note.
Advantages
- Readily welded — 95/100, better than 97% of steel grades
- Easy to machine — 68/100, better than 95% of steel grades
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
- Forms and bends easily — 80/100, better than 93% of steel grades
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades
Limitations
- Low strength — 280 MPa (40.6 ksi), worse than 90% of steel grades
Q235B-CR properties
Typical room-temperature values for Q235B-CR; 12 are specific to this condition. Other listed values are Q235B reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
Q235B-CR 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
Q235B-CR has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 90% of steel grades. Elongation at break is 26% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
Q235B-CR 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 12 µm/m·K (6.67 µin/in·°F).
Electrical3
Q235B-CR 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 Q235B-CR takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability8
Q235B-CR's machinability is good (68/100, better than 95% of steel grades); weldability excellent (95/100); formability very good (80/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Q235B-CR
Is Q235B easy to machine?
Easy but gummy — low-carbon steel tears and builds up on the edge; use sharp positive-rake tooling, generous feed and coolant, expect ~70 % of 1212 speeds.
Can Q235B be welded?
Prequalified for all arc processes (SMAW/GMAW/FCAW/SAW) with E43xx/ER70S-6 consumables, no preheat needed below ~30 mm and no PWHT; remove mill scale, zinc or oil first.
Can Q235B be formed, bent or molded?
Excellent cold bending, roll forming and stamping; keep bend radius ≥1×t for HR plate, and bend across the rolling direction on thick sections.
What surface finishes work on Q235B?
No anodizing; protect by shot-blast + primer/paint, phosphate, zinc plating or hot-dip galvanizing — bare surfaces flash-rust within hours in humid air.
Q235B 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 Q235B | 0.12 – 0.2 | 0.17 |
| Si | ≤ 0.35 | 0.25 |
| Mn | ≤ 1.4 | 0.5 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Febalance, residual Cu/Cr/Ni/Mo as tramp elements | balance |
Q235B-CR — frequently asked
What is Q235B-CR used for?
Q235B-CR is typically used for welded structural frames, building and platform framing, base plates and gussets, brackets and mounting plates, machine bases and weldments and bridge structural members. In short: chinese mild-steel sheet.
What is the yield strength of Q235B-CR?
Q235B-CR has a typical yield strength of 280 MPa (40.6 ksi) and a tensile strength of 420 MPa (60.9 ksi) — weaker than 90% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is Q235B-CR easy to machine?
Reasonably — machinability is rated good (68/100, better than 95% of steel grades). Easy but gummy — low-carbon steel tears and builds up on the edge; use sharp positive-rake tooling, generous feed and coolant, expect ~70 % of 1212 speeds.
Can Q235B-CR be welded?
Yes — weldability is rated excellent (95/100). Prequalified for all arc processes (SMAW/GMAW/FCAW/SAW) with E43xx/ER70S-6 consumables, no preheat needed below ~30 mm and no PWHT; remove mill scale, zinc or oil first.
What surface finishes work on Q235B-CR?
No anodizing; protect by shot-blast + primer/paint, phosphate, zinc plating or hot-dip galvanizing — bare surfaces flash-rust within hours in humid air.
Can Q235B-CR be formed, bent or molded?
Excellent cold bending, roll forming and stamping; keep bend radius ≥1×t for HR plate, and bend across the rolling direction on thick sections.
What is the maximum service temperature of Q235B-CR?
Q235B-CR 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 Q235B-HR and Q235B-CD?
HR is the default condition — default stock condition for structural plate, angle, channel, beam and hot-rolled coil; cheapest and most widely available. CD: pick for turned/machined shafts and fasteners where bright surface, straightness and higher yield strength are required. Yield strength is 250 MPa in HR versus 380 MPa in CD.
Can FabDigit make parts in Q235B-CR?
Yes — Q235B-CR 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 3274 / GB/T 709 hot-rolled plate & coil dimensions and quality — SAC (China) (2017)
- EN 10025-2 (S235JR comparison grade) — CEN (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- GB 50017 (elastic constants, allowable stress) — MOHURD (2017)
- worldsteel LCI methodology report (steel embodied energy/carbon) — World Steel Association (2023)
- Mysteel / 1688 Q235B — Mysteel (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.