Steel A570-GR33
Grade
ASTM A570
GR33 = grade 33
Slight strength step up from Gr30 while keeping good bendability.
Values for the GR33 condition
Other A570 tempers and conditions
A570 is listed in 7 conditions; see the grade overview at A570.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Grade 30 | Softest, most formable A570 grade — pick for parts needing tight bends or deeper stamping. | 240 | 365 | 27 | 105 HB | — |
GR33This page Grade 33 | Slight strength step up from Gr30 while keeping good bendability. | 265 | 385 | 24 | 112 HB | — |
GR36Default Grade 36 | The default stocked grade — A36-equivalent strength in sheet/strip thickness for general brackets, frames and stampings. | 285 | 400 | 22 | 120 HB | — |
Hot rolled, pickled and oiled | Descaled surface for direct painting, e-coating or close-tolerance forming without mill scale pickup on dies. | 285 | 400 | 23 | 118 HB | 10.8 % IACS |
Grade 40 | Higher-Mn grade for moderately loaded roll-formed sections where weight saving matters. | 310 | 420 | 20 | 130 HB | — |
Grade 45 | Use where section thickness must be reduced; expect larger bend radii and more springback. | 345 | 455 | 18 | 140 HB | — |
Grade 50 | Strongest A570 grade for light high-strength stampings and tube stock; lowest ductility of the family. | 380 | 490 | 16 | 150 HB | — |
What is A570-GR33?
A570-GR33 is A570 in the GR33 grade — slight strength step up from Gr30 while keeping good bendability. A570-GR33 has a yield strength of 265 MPa (38.4 ksi) and a tensile strength of 385 MPa (55.8 ksi) — weaker than 92% of steel grades. Elongation at break is 24% and the elastic modulus is 200 GPa (29 Msi). A570-GR33 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). GR36 is the default condition FabDigit quotes; GR33 is available on request or by drawing note.
Advantages
- Conducts heat well — 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades
- Readily welded — 93/100, better than 95% of steel grades
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
- Forms and bends easily — 74/100, better than 89% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
Limitations
- Hard to polish — 40/100, worse than 96% of steel grades
- Low strength — 265 MPa (38.4 ksi), worse than 92% of steel grades
A570-GR33 properties
Typical room-temperature values for A570-GR33; 10 are specific to this condition. Other listed values are A570 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A570-GR33 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).
Mechanical14
A570-GR33 has a yield strength of 265 MPa (38.4 ksi) and a tensile strength of 385 MPa (55.8 ksi) — weaker than 92% of steel grades. Elongation at break is 24% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
A570-GR33 is rated for continuous service to 400°C (752 °F). It conducts heat at 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
A570-GR33 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 A570-GR33 takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
A570-GR33's machinability is good (60/100, better than 83% of steel grades); weldability excellent (93/100); formability very good (74/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A570-GR33
Is A570 easy to machine?
Cuts easily with HSS or carbide at ~60 % of 1212; gummy chips in the low-strength grades — use sharp positive rake and flood coolant, and expect burrs on punched edges.
Can A570 be welded?
Carbon equivalent below ~0.35, so all arc processes (GMAW/SMAW/RSW) run without preheat on thin sheet; use ER70S-6 / E7018 class filler.
Can A570 be formed, bent or molded?
Structural quality, not drawing quality: press-brake and roll-form freely with bend radii of 1–2t for Gr30–36 and 2–3t for Gr45–50; account for springback and mill-scale die wear.
What surface finishes work on A570?
Must be protected — pickle or shot blast the scale, then phosphate + paint, e-coat, zinc plate or hot-dip galvanize; no anodizing.
A570 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, all grades | ≤ 0.25 | 0.16 |
| Mn0.90 max for Gr30/33/36; 1.35 max for Gr40/45/50 | ≤ 1.35 | 0.7 |
| Pheat analysis | ≤ 0.04 | 0.02 |
| Sheat analysis | ≤ 0.04 | 0.02 |
| Sinot specified in A570; typical mill practice / killed steels | ≤ 0.3 | 0.05 |
| Fe | balance | — |
A570-GR33 — frequently asked
What is A570-GR33 used for?
A570-GR33 is typically used for light structural parts, automotive frames and stamped brackets. In short: structural-quality hot-rolled sheet; six strength grades stocked; not drawing quality.
What is the yield strength of A570-GR33?
A570-GR33 has a typical yield strength of 265 MPa (38.4 ksi) and a tensile strength of 385 MPa (55.8 ksi) — weaker than 92% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is A570-GR33 easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Cuts easily with HSS or carbide at ~60 % of 1212; gummy chips in the low-strength grades — use sharp positive rake and flood coolant, and expect burrs on punched edges.
Can A570-GR33 be welded?
Yes — weldability is rated excellent (93/100). Carbon equivalent below ~0.35, so all arc processes (GMAW/SMAW/RSW) run without preheat on thin sheet; use ER70S-6 / E7018 class filler.
What surface finishes work on A570-GR33?
Must be protected — pickle or shot blast the scale, then phosphate + paint, e-coat, zinc plate or hot-dip galvanize; no anodizing.
Can A570-GR33 be formed, bent or molded?
Structural quality, not drawing quality: press-brake and roll-form freely with bend radii of 1–2t for Gr30–36 and 2–3t for Gr45–50; account for springback and mill-scale die wear.
What is the maximum service temperature of A570-GR33?
A570-GR33 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A570-GR36 and A570-Gr50?
GR36 is the default condition — the default stocked grade — A36-equivalent strength in sheet/strip thickness for general brackets, frames and stampings. Gr50: strongest A570 grade for light high-strength stampings and tube stock; lowest ductility of the family. Yield strength is 285 MPa in GR36 versus 380 MPa in Gr50.
Sources
- ASTM A570/A570M Standard Specification for Steel, Sheet and Strip, Carbon, Hot-Rolled, Structural Quality (withdrawn, replaced by A1011) — ASTM International (1998)
- ASTM A1011/A1011M Steel Sheet and Strip, Hot-Rolled, Carbon, Structural, HSLA — ASTM International (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook, 31st ed. — Industrial Press (2020)
- worldsteel LCI data for hot rolled coil — World Steel Association (2023)
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.