Steel A242 HR-46
Heat-treated state
ASTM A242 · UNS K11510
HR-46 = hot Rolled, 19–38 mm
Medium plate thickness class — same chemistry, strength de-rated by section size.
Values for the HR-46 condition
Other A242 tempers and conditions
A242 is listed in 5 conditions; see the grade overview at A242.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot Rolled, 38–100 mm | Heavy plate class for thick bridge and structural sections; lowest strength grade of A242. | 315 | 465 | 23 | 145 HB | 8.5 % IACS |
HR-46This page Hot Rolled, 19–38 mm | Medium plate thickness class — same chemistry, strength de-rated by section size. | 340 | 490 | 24 | 150 HB | 8.5 % IACS |
Normalized | Specified for thick plate or low-temperature service where refined grain size and higher CVN toughness are needed. | 360 | 500 | 26 | 150 HB | 8.5 % IACS |
HR-50Default Hot Rolled, t ≤ 19 mm | Standard as-rolled plate, sheet and shapes up to 3/4 in — the normally stocked weathering-steel condition. | 370 | 510 | 24 | 155 HB | — |
Cold rolled | Thin sheet/coil equivalents (A606-type) for cladding, containers and railcar panels where extra strength and flatness are wanted. | 400 | 520 | 20 | 170 HB | 8.5 % IACS |
What is A242 HR-46?
A242 HR-46 is A242 heat treated to HR-46 — medium plate thickness class — same chemistry, strength de-rated by section size. A242 HR-46 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 76% of steel grades. Elongation at break is 24% and the elastic modulus is 200 GPa (29 Msi). A242 HR-46 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F). HR-50 is the default condition FabDigit quotes; HR-46 is available on request or by drawing note.
Advantages
- Good corrosion resistance — 35/100, better than 97% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Forms and bends easily — 66/100, better than 83% of steel grades
- Conducts heat well — 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades
- Readily welded — 80/100, better than 79% of steel grades
Limitations
- Hard to polish — 40/100, worse than 96% of steel grades
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
A242 HR-46 properties
Typical room-temperature values for A242 HR-46; 22 are specific to this condition. Other listed values are A242 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A242 HR-46 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
A242 HR-46 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 76% of steel grades. Elongation at break is 24% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
A242 HR-46 is rated for continuous service to 350°C (662 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
A242 HR-46 conducts electricity at 8.5 % IACS, better than 63% of steel grades.
Chemical & Environmental3
Corrosion resistance is fair (35/100), better than 97% of steel grades.
Sustainability4
Producing a kilogram of A242 HR-46 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
A242 HR-46's machinability is good (60/100, better than 83% of steel grades); weldability very good (80/100); formability good (66/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A242 HR-46
Is A242 easy to machine?
Machines like a 350 MPa-yield HSLA steel (~60 % of 1212); use rigid setups and sharp carbide, mild work-hardening and stringy chips at low feeds.
Can A242 be welded?
Readily welded by SMAW/GMAW/SAW; use weathering-matching Cu-Ni-Cr consumables (e.g. E80xx-W, ER80S-G) so the weld patinas with the base metal, preheat 50–100 °C on thick or high-P heats.
Can A242 be formed, bent or molded?
Cold bend with r ≥ 2t transverse to rolling direction; hot form 900–1100 °C and air cool, avoid forming in the 250–400 °C blue-brittle range.
What surface finishes work on A242?
Normally left bare to develop its own patina — needs alternating wet/dry exposure and free drainage; if painted, blast to SA 2.5 and use a zinc-rich epoxy system, and detail to prevent rust-run staining of adjacent concrete.
A242 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 |
|---|---|---|
| CA242 Type 1 max | ≤ 0.15 | 0.11 |
| Mn | ≤ 1 | 0.4 |
| PP deliberately used for patina stabilization (Corten A style) | ≤ 0.15 | 0.09 |
| S | ≤ 0.05 | 0.02 |
| Sitypical Corten A / Q355NH practice, not fixed by A242 | 0.15 – 0.75 | 0.4 |
| Cu0.20 % min required by A242 | 0.2 – 0.55 | 0.35 |
| Crtypical weathering addition | 0.3 – 1.25 | 0.7 |
| Nitypical weathering addition | ≤ 0.65 | 0.3 |
| Fe | balance | — |
A242 HR-46 — frequently asked
What is A242 HR-46 used for?
A242 HR-46 is typically used for railcar bodies, bridges, outdoor structural plate and architectural weathering panels. In short: original weathering steel plate; paint-free outdoor service; corten A predecessor grade.
What is the yield strength of A242 HR-46?
A242 HR-46 has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 76% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A242 HR-46 easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines like a 350 MPa-yield HSLA steel (~60 % of 1212); use rigid setups and sharp carbide, mild work-hardening and stringy chips at low feeds.
Can A242 HR-46 be welded?
Yes — weldability is rated very good (80/100). Readily welded by SMAW/GMAW/SAW; use weathering-matching Cu-Ni-Cr consumables (e.g. E80xx-W, ER80S-G) so the weld patinas with the base metal, preheat 50–100 °C on thick or high-P heats.
What surface finishes work on A242 HR-46?
Normally left bare to develop its own patina — needs alternating wet/dry exposure and free drainage; if painted, blast to SA 2.5 and use a zinc-rich epoxy system, and detail to prevent rust-run staining of adjacent concrete.
Can A242 HR-46 be formed, bent or molded?
Cold bend with r ≥ 2t transverse to rolling direction; hot form 900–1100 °C and air cool, avoid forming in the 250–400 °C blue-brittle range.
What is the maximum service temperature of A242 HR-46?
A242 HR-46 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 A242 HR-50 and A242 HR-42?
HR-50 is the default condition — standard as-rolled plate, sheet and shapes up to 3/4 in — the normally stocked weathering-steel condition. HR-42: heavy plate class for thick bridge and structural sections; lowest strength grade of A242. Yield strength is 370 MPa in HR-50 versus 315 MPa in HR-42.
Sources
- ASTM A242/A242M — High-Strength Low-Alloy Structural Steel — ASTM International (2018)
- ASTM G101 — Estimating Atmospheric Corrosion Resistance of Low-Alloy Steels — ASTM International (2020)
- GB/T 4171 (Q355NH etc.) — SAC (2008)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
- COR-TEN A / COR-TEN B weathering steel data — U.S. Steel / SSAB (2020)
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.