Steel A285 · grade
Steel A285 Gr.B
Properties of the Gr.B condition, compared with the other A285 tempers.
Middle strength/ductility compromise when Grade A is too weak but full Grade C carbon is unwelcome for welding.
What is A285 Gr.B?
A285 Gr.B is A285 in the Gr.B grade — middle strength/ductility compromise when Grade A is too weak but full Grade C carbon is unwelcome for welding. A285 Gr.B has a yield strength of 215 MPa (31.2 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 98% of steel grades. Elongation at break is 28% and the elastic modulus is 200 GPa (29 Msi). A285 Gr.B has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F). HR is the default condition FabDigit quotes; Gr.B is available on request or by drawing note.
Advantages
- Easy to machine — 66/100, better than 95% of steel grades
- Forms and bends easily — 84/100, better than 94% of steel grades
- Readily welded — 92/100, better than 93% of steel grades
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
Limitations
- Low strength — 215 MPa (31.2 ksi), worse than 98% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
A285 Gr.B properties
Typical room-temperature values for A285 Gr.B — 34 properties are specific to this condition; the rest are grade-level values shared by every A285 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
A285 Gr.B has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F).
Mechanical15
A285 Gr.B has a yield strength of 215 MPa (31.2 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 98% of steel grades. Elongation at break is 28% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
A285 Gr.B is rated for continuous service to 425°C (797 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
A285 Gr.B conducts electricity at 10.5 % IACS, better than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 87% of steel grades.
Sustainability4
Producing a kilogram of A285 Gr.B takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
A285 Gr.B's machinability is good (66/100, better than 95% of steel grades); weldability excellent (92/100); formability very good (84/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other A285 tempers and conditions
A285 is also supplied in 7 other conditions. The full side-by-side table is on the A285 overview.
- HRDefaultStandard stock condition for A285 pressure-vessel plate; take it for ordinary welded tanks and boiler shells with no low-temperature requirement.250 MPa yield · 130 HB
- Q&TRarely used for A285 (carbon too low for real hardenability); ordered only where slightly higher yield and best low-temperature toughness are needed in thin plate.320 MPa yield · 145 HB
- NormalizedSpecify for heavier plate or when uniform fine grain and better notch toughness are wanted (supplementary impact testing).260 MPa yield · 132 HB
- Gr.CMost commonly stocked A285 grade; use for the highest allowable stress of the specification in storage tanks and low-pressure vessels.240 MPa yield · 130 HB
- AnnealedChoose when maximum ductility and lowest residual stress are needed for severe cold forming or after heavy weld fabrication (PWHT).225 MPa yield · 118 HB
- Gr.BMiddle strength/ductility compromise when Grade A is too weak but full Grade C carbon is unwelcome for welding.215 MPa yield · 120 HB
- Gr.ASoftest, most weldable and most formable A285 grade; pick it for deeply dished heads and low design-pressure tanks.190 MPa yield · 110 HB
Working with A285 Gr.B
Is A285 easy to machine?
Machines easily but gummy — use positive rake, sharp tools and generous coolant to avoid built-up edge and torn threads; drilling and plasma/oxy cutting are routine.
Can A285 be welded?
Excellent weldability by SMAW/GMAW/SAW with E70xx-class filler; no preheat below ~25 mm, preheat 100 °C for heavy sections, PWHT per ASME VIII when required by thickness or service.
Can A285 be formed, bent or molded?
Very good cold formability for shells, dished heads and rolled sections; hot form 900–1200 °C and re-normalize if cold strain exceeds code limits.
What surface finishes work on A285?
No passive film — must be blast-cleaned and painted, epoxy-lined, galvanized or metallized; phosphate pretreatment improves paint adhesion.
A285 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 |
|---|---|---|
| Cheat analysis max: Gr A 0.17, Gr B 0.22, Gr C 0.28 | ≤ 0.28 | 0.2 |
| Mnheat analysis max (0.98 product analysis) | ≤ 0.9 | 0.6 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.01 |
| Sinot specified by A285; typical mill practice (killed/semi-killed) | ≤ 0.4 | 0.2 |
| Fe | balance | — |
A285 Gr.B — frequently asked
What is A285 Gr.B used for?
A285 Gr.B is typically used for boilers, storage tanks and petrochemical vessels. In short: pressure-vessel quality plate.
What is the yield strength of A285 Gr.B?
A285 Gr.B has a typical yield strength of 215 MPa (31.2 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 98% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is A285 Gr.B easy to machine?
Reasonably — machinability is rated good (66/100, better than 95% of steel grades). Machines easily but gummy — use positive rake, sharp tools and generous coolant to avoid built-up edge and torn threads; drilling and plasma/oxy cutting are routine.
Can A285 Gr.B be welded?
Yes — weldability is rated excellent (92/100). Excellent weldability by SMAW/GMAW/SAW with E70xx-class filler; no preheat below ~25 mm, preheat 100 °C for heavy sections, PWHT per ASME VIII when required by thickness or service.
What surface finishes work on A285 Gr.B?
No passive film — must be blast-cleaned and painted, epoxy-lined, galvanized or metallized; phosphate pretreatment improves paint adhesion.
Can A285 Gr.B be formed, bent or molded?
Very good cold formability for shells, dished heads and rolled sections; hot form 900–1200 °C and re-normalize if cold strain exceeds code limits.
What is the maximum service temperature of A285 Gr.B?
A285 Gr.B is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in A285 Gr.B?
Yes — A285 Gr.B 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
- ASTM A285/A285M — Pressure Vessel Plates, Carbon Steel, Low- and Intermediate-Tensile Strength — ASTM International (2017)
- ASME BPVC Section II Part D — Properties (Metric) — ASME (2023)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook, 31st ed. (machinability ratings) — Industrial Press (2020)
- GB/T 713 Q245R (comparable grade) — SAC (2014)
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.