Steel SPA-H HRPO
Finish state
HRPO = hot rolled, pickled and oiled
Choose when the sheet goes straight to stamping, painting or controlled patina formation and mill scale is unacceptable.
Values for the HRPO condition
Other SPA-H tempers and conditions
SPA-H is listed in 4 conditions; see the grade overview at SPA-H.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Cold rolled and annealed thin sheet | Thin-gauge weathering sheet for deep-drawn or tightly formed outdoor housings and roofing where tight thickness tolerance and smooth surface are needed. | 370 | 500 | 32 | 150 HB | 7.8 % IACS |
HRPOThis page Hot rolled, pickled and oiled | Choose when the sheet goes straight to stamping, painting or controlled patina formation and mill scale is unacceptable. | 385 | 515 | 29 | 158 HB | 7.8 % IACS |
HRDefault Hot rolled | Standard stocked condition for containers, wagon panels and weathering-steel structures; scale must be removed before painting or before patina development. | 390 | 520 | 28 | 160 HB | 7.8 % IACS |
Cold rolled full hard | Only for flat parts or simple bends where high strength and stiffness matter more than ductility; strain-hardened and directional. | 580 | 650 | 6 | 14 HRC | 7.5 % IACS |
What is SPA-H HRPO?
SPA-H HRPO is SPA-H supplied in the HRPO condition — choose when the sheet goes straight to stamping, painting or controlled patina formation and mill scale is unacceptable. SPA-H HRPO has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 515 MPa (74.7 ksi) — weaker than 65% of steel grades. Elongation at break is 29% and the elastic modulus is 205 GPa (29.7 Msi). SPA-H HRPO has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,480°C (2,696 °F). HR is the default condition FabDigit quotes; HRPO is available on request or by drawing note.
Advantages
- Good corrosion resistance — 32/100, better than 96% of steel grades
- Ductile — tolerates forming and impact — 29%, better than 91% of steel grades
- Forms and bends easily — 72/100, better than 88% of steel grades
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades
- Readily welded — 80/100, better than 79% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
SPA-H HRPO properties
Typical room-temperature values for SPA-H HRPO; 21 are specific to this condition. Other listed values are SPA-H reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SPA-H HRPO has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,480°C (2,696 °F).
Mechanical16
SPA-H HRPO has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 515 MPa (74.7 ksi) — weaker than 65% of steel grades. Elongation at break is 29% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SPA-H HRPO 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 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
SPA-H HRPO conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (32/100), better than 96% of steel grades.
Sustainability4
Producing a kilogram of SPA-H HRPO takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
SPA-H HRPO's machinability is good (60/100, better than 83% of steel grades); weldability very good (80/100); formability very good (72/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SPA-H HRPO
Is SPA-H easy to machine?
Machines like a 500 MPa HSLA steel — about 60 % of 1212; use rigid setups and coated carbide, and expect somewhat gummy chips from the low carbon content.
Can SPA-H be welded?
Excellent weldability with low carbon equivalent; for exposed patina joints use weathering-matched consumables (e.g. AWS E8018-W2 / ER80S-Ni1 or Cu-Cr filler) so the weld rusts at the same rate, and avoid heavy restraint in the higher-P heats.
Can SPA-H be formed, bent or molded?
Good cold forming and roll forming in hot-rolled or annealed condition; keep bend lines transverse to rolling where possible and use ≥2t inside radius on 490 MPa-class sheet.
What surface finishes work on SPA-H?
Remove mill scale before painting or before intentional patina formation; phosphate + epoxy primer for painted service, or leave bare/pre-rusted for architectural patina — do not use in salt-spray or permanently wet zones without coating.
SPA-H 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 |
|---|---|---|
| CJIS G 3125 | ≤ 0.12 | 0.09 |
| Si | 0.25 – 0.75 | 0.45 |
| Mn | 0.2 – 0.5 | 0.35 |
| Pdeliberate addition for atmospheric resistance | 0.07 – 0.15 | 0.1 |
| S | ≤ 0.04 | 0.01 |
| Cu | 0.25 – 0.6 | 0.35 |
| Cr | 0.3 – 1.25 | 0.7 |
| Ni | ≤ 0.65 | 0.15 |
| Fe | balance | — |
SPA-H HRPO — frequently asked
What is SPA-H HRPO used for?
SPA-H HRPO is typically used for shipping containers, outdoor equipment housings and truck bodies. In short: weathering steel in sheet form; paint-free outdoor service; formable 490 MPa-class sheet.
What is the yield strength of SPA-H HRPO?
SPA-H HRPO has a typical yield strength of 385 MPa (55.8 ksi) and a tensile strength of 515 MPa (74.7 ksi) — weaker than 65% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is SPA-H HRPO easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines like a 500 MPa HSLA steel — about 60 % of 1212; use rigid setups and coated carbide, and expect somewhat gummy chips from the low carbon content.
Can SPA-H HRPO be welded?
Yes — weldability is rated very good (80/100). Excellent weldability with low carbon equivalent; for exposed patina joints use weathering-matched consumables (e.g. AWS E8018-W2 / ER80S-Ni1 or Cu-Cr filler) so the weld rusts at the same rate, and avoid heavy restraint in the higher-P heats.
What surface finishes work on SPA-H HRPO?
Remove mill scale before painting or before intentional patina formation; phosphate + epoxy primer for painted service, or leave bare/pre-rusted for architectural patina — do not use in salt-spray or permanently wet zones without coating.
Can SPA-H HRPO be formed, bent or molded?
Good cold forming and roll forming in hot-rolled or annealed condition; keep bend lines transverse to rolling where possible and use ≥2t inside radius on 490 MPa-class sheet.
What is the maximum service temperature of SPA-H HRPO?
SPA-H HRPO 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 SPA-H-HR and SPA-H CR-FH?
HR is the default condition — standard stocked condition for containers, wagon panels and weathering-steel structures; scale must be removed before painting or before patina development. CR-FH: only for flat parts or simple bends where high strength and stiffness matter more than ductility; strain-hardened and directional. Yield strength is 390 MPa in HR versus 580 MPa in CR-FH.
Sources
- JIS G 3125 — Superior atmospheric corrosion resisting rolled steels — JISC (2021)
- ASTM A606/A606M — High-strength low-alloy sheet and strip with improved atmospheric corrosion resistance — ASTM (2018)
- ASTM G101 — Estimating the atmospheric corrosion resistance of low-alloy steels — ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.13 — Corrosion — ASM International (2005)
- GB/T 4171 — (weathering structural steel) — SAC (2008)
- 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.