Steel A606 Type 4 HRPO
Finish state
ASTM A606 Type 4
HRPO = hot rolled, pickled and oiled
Choose when a scale-free surface is needed for forming, painting or an even start to the patina.
Values for the HRPO condition
Other A606 Type 4 tempers and conditions
A606 Type 4 is listed in 4 conditions; see the grade overview at A606 Type 4.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled, annealed or normalized | Softened hot-rolled condition for severe forming or improved toughness; lower strength minima per ASTM A606. | 330 | 470 | 30 | 140 HB | 9 % IACS |
Cold rolled | Cold-rolled thin gauge with tighter thickness tolerance and smoother surface, for enclosures and formed panels. | 340 | 480 | 26 | 150 HB | 9 % IACS |
HRPOThis page Hot rolled, pickled and oiled | Choose when a scale-free surface is needed for forming, painting or an even start to the patina. | 375 | 510 | 27 | 150 HB | 9 % IACS |
HRDefault Hot rolled | Standard stocked condition: hot-rolled weathering coil/sheet for structural and architectural use with bare patina. | 380 | 510 | 26 | 155 HB | 9 % IACS |
What is A606 Type 4 HRPO?
A606 Type 4 HRPO is A606 Type 4 supplied in the HRPO condition — choose when a scale-free surface is needed for forming, painting or an even start to the patina. A606 Type 4 HRPO has a yield strength of 375 MPa (54.4 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 70% of steel grades. Elongation at break is 27% and the elastic modulus is 205 GPa (29.7 Msi). A606 Type 4 HRPO has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). HR is the default condition FabDigit quotes; HRPO is available on request or by drawing note.
Advantages
- Good corrosion resistance — 28/100, better than 94% of steel grades
- Ductile — tolerates forming and impact — 27%, better than 86% of steel grades
- Readily welded — 85/100, better than 83% of steel grades
- Forms and bends easily — 66/100, better than 83% of steel grades
A606 Type 4 HRPO properties
Typical room-temperature values for A606 Type 4 HRPO; 22 are specific to this condition. Other listed values are A606 Type 4 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A606 Type 4 HRPO has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical15
A606 Type 4 HRPO has a yield strength of 375 MPa (54.4 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 70% of steel grades. Elongation at break is 27% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
A606 Type 4 HRPO is rated for continuous service to 400°C (752 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
A606 Type 4 HRPO conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (28/100), better than 94% of steel grades.
Sustainability4
Producing a kilogram of A606 Type 4 HRPO takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
A606 Type 4 HRPO's machinability is good (58/100, better than 75% of steel grades); weldability excellent (85/100); formability good (66/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A606 Type 4 HRPO
Is A606 Type 4 easy to machine?
Machines like a 60 ksi HSLA sheet steel — sharp tools, moderate speeds; thin gauge is normally laser/plasma/waterjet cut or punched rather than milled.
Can A606 Type 4 be welded?
Readily welded by GMAW/SMAW/laser; use matching weathering-grade consumables (e.g. E80xx-W, ER80S-G) so the weld patinas like the base metal, and avoid excessive dilution on thin gauge.
Can A606 Type 4 be formed, bent or molded?
Cold forms and roll-forms well at 22 % minimum elongation; use bend radii ≥1–2t transverse to rolling direction and de-scale hot-rolled material before tight bends.
What surface finishes work on A606 Type 4?
Usually left bare to develop the patina (alternate wetting/drying required); can also be pre-oxidized, phosphated and painted or powder coated — but detail for drainage, and isolate from aluminium and galvanized parts to avoid staining and galvanic attack.
A606 Type 4 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, ASTM A606 | ≤ 0.22 | 0.1 |
| MnSPA-H typically 0.20–0.50 | ≤ 1.25 | 0.4 |
| Pintentional P addition for patina (SPA-H / Cor-Ten A type) | 0.06 – 0.15 | 0.09 |
| S | ≤ 0.04 | 0.01 |
| Si | 0.25 – 0.75 | 0.4 |
| Cukey weathering element | 0.25 – 0.6 | 0.35 |
| Cr | 0.3 – 1.25 | 0.6 |
| Ni | ≤ 0.65 | 0.2 |
| FeASTM A606 Type 4 specifies corrosion index ≥ 6.0 per ASTM G101 rather than fixed limits; values shown are typical SPA-H/JIS G3125 practice | balance | — |
A606 Type 4 HRPO — frequently asked
What is A606 Type 4 HRPO used for?
A606 Type 4 HRPO is typically used for truck bodies, agricultural equipment, outdoor enclosures and guardrails. In short: weathering HSLA in sheet; formable bare-exposure coil; SPA-H sheet equivalent.
What is the yield strength of A606 Type 4 HRPO?
A606 Type 4 HRPO has a typical yield strength of 375 MPa (54.4 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 70% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is A606 Type 4 HRPO easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like a 60 ksi HSLA sheet steel — sharp tools, moderate speeds; thin gauge is normally laser/plasma/waterjet cut or punched rather than milled.
Can A606 Type 4 HRPO be welded?
Yes — weldability is rated excellent (85/100). Readily welded by GMAW/SMAW/laser; use matching weathering-grade consumables (e.g. E80xx-W, ER80S-G) so the weld patinas like the base metal, and avoid excessive dilution on thin gauge.
What surface finishes work on A606 Type 4 HRPO?
Usually left bare to develop the patina (alternate wetting/drying required); can also be pre-oxidized, phosphated and painted or powder coated — but detail for drainage, and isolate from aluminium and galvanized parts to avoid staining and galvanic attack.
Can A606 Type 4 HRPO be formed, bent or molded?
Cold forms and roll-forms well at 22 % minimum elongation; use bend radii ≥1–2t transverse to rolling direction and de-scale hot-rolled material before tight bends.
What is the maximum service temperature of A606 Type 4 HRPO?
A606 Type 4 HRPO 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 A606 Type 4-HR and A606 Type 4 HR-AN?
HR is the default condition — standard stocked condition: hot-rolled weathering coil/sheet for structural and architectural use with bare patina. HR-AN: softened hot-rolled condition for severe forming or improved toughness; lower strength minima per ASTM A606. Yield strength is 380 MPa in HR versus 330 MPa in HR-AN.
Sources
- ASTM A606/A606M — High-Strength, Low-Alloy, Hot-Rolled and Cold-Rolled Steel Sheet and Strip with Improved Atmospheric Corrosion Resistance — ASTM International (2018)
- ASTM G101 — Estimating the Atmospheric Corrosion Resistance of Low-Alloy Steels — ASTM International (2020)
- JIS G 3125 — Superior Atmospheric Corrosion Resisting Rolled Steels (SPA-H/SPA-C) — JSA (2021)
- GB/T 4171 — (Q355NH/Q345NH) — SAC (2008)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Weathering steel sheet/coil datasheets (Cor-Ten type) — steel producers (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.