Steel SPA-H
SPA-H is a hot-rolled weathering (atmospheric-corrosion-resistant) sheet steel of the HSLA family, alloyed with copper, phosphorus, chromium and nickel and cross-listed as A606 Type 4.
Reference datasheet — SPA-H is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the HR condition
SPA-H tempers and conditions
SPA-H is supplied in 4 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
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 |
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 |
Supply forms, finishes and certifications
Ways SPA-H is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
PRE-RUST | Pre-weathered / accelerated-patina finish | Surface finish |
What is SPA-H?
SPA-H is a hot-rolled weathering (atmospheric-corrosion-resistant) sheet steel of the HSLA family, alloyed with copper, phosphorus, chromium and nickel and cross-listed as A606 Type 4. Engineers use it where a self-protecting rust patina replaces paint on formed sheet parts; it is stocked as hot-rolled, hot-rolled pickled and oiled, cold-rolled annealed, cold-rolled full-hard and pre-rusted coil, with typical values of 390 MPa yield, 520 MPa tensile, 28 % elongation and 160 HB (84 HRB). The patina only forms under wet-dry cycling, so the grade is not a substitute for coating in salt-spray, de-icing-salt or permanently wet zones, and rust run-off stains adjacent surfaces. In plate thicknesses the usual alternative is A588 / Q355NH. SPA-H 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). SPA-H has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 64% of steel grades. Elongation at break is 28% and the elastic modulus is 205 GPa (29.7 Msi).
What is SPA-H used for?
- shipping containers
- outdoor equipment housings
- truck bodies
Advantages
- Good corrosion resistance — 32/100, better than 96% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades
- Forms and bends easily — 68/100, better than 83% 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 properties
Typical room-temperature values for SPA-H-HR; bars are the position among steel grades.
Physical3
SPA-H 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 has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 64% of steel grades. Elongation at break is 28% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SPA-H 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 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 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's machinability is good (60/100, better than 83% of steel grades); weldability very good (80/100); formability good (68/100).
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. SPA-H is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SPA-H
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.
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 |
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.
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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel SPA-H in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- A606 Type 4
How much does SPA-H cost?
SPA-H is a budget-cost steel ($), cheaper than about 90% 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.
SPA-H — frequently asked
What is SPA-H used for?
SPA-H 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?
SPA-H has a typical yield strength of 390 MPa (56.6 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 64% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is SPA-H 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 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?
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 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?
SPA-H 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.
How much does SPA-H cost?
SPA-H is a budget-cost steel ($), cheaper than about 90% 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.
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; 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.