Steel SMA490W TMCP
Supply condition
TMCP = thermomechanically controlled processed
Pick for heavy weathering plate needing low carbon equivalent, better weldability and high toughness without normalizing.
Values for the TMCP condition
Other SMA490W tempers and conditions
SMA490W is listed in 3 conditions; see the grade overview at SMA490W.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Normalized | Choose for thick plate or when guaranteed −5 °C/0 °C Charpy values and fine grain are specified. | 380 | 530 | 26 | 155 HB | 7.8 % IACS |
AR-HRDefault As-Rolled | Standard stocked condition for weathering-steel plate, strip and shapes up to moderate thickness. | 390 | 540 | 24 | 160 HB | 7.8 % IACS |
TMCPThis page Thermomechanically controlled processed | Pick for heavy weathering plate needing low carbon equivalent, better weldability and high toughness without normalizing. | 400 | 550 | 26 | 165 HB | 7.8 % IACS |
What is SMA490W TMCP?
SMA490W TMCP is SMA490W supplied in the TMCP condition — pick for heavy weathering plate needing low carbon equivalent, better weldability and high toughness without normalizing. SMA490W TMCP has a yield strength of 400 MPa (58 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 60% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi). SMA490W TMCP has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,470°C (2,678 °F). AR-HR is the default condition FabDigit quotes; TMCP is available on request or by drawing note.
Advantages
- Good corrosion resistance — 32/100, better than 96% of steel grades
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
- Readily welded — 88/100, better than 87% of steel grades
- Forms and bends easily — 70/100, better than 86% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
Limitations
- Hard to polish — 40/100, worse than 96% of steel grades
SMA490W TMCP properties
Typical room-temperature values for SMA490W TMCP; 23 are specific to this condition. Other listed values are SMA490W reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SMA490W TMCP has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,470°C (2,678 °F).
Mechanical16
SMA490W TMCP has a yield strength of 400 MPa (58 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 60% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SMA490W TMCP is rated for continuous service to 350°C (662 °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 µm/m·K (6.67 µin/in·°F).
Electrical3
SMA490W TMCP 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 SMA490W TMCP takes about 26 MJ of energy and emits 2.1 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 25%.
Manufacturability6
SMA490W TMCP's machinability is good (55/100, better than 62% of steel grades); weldability excellent (88/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SMA490W TMCP
Is SMA490W easy to machine?
Drills, saws and mills like A588/Q345 plate at ~60 % of 1212 speeds; use rigid setups and sharp carbide, expect mildly gummy chips from the higher Cu/Cr.
Can SMA490W be welded?
Readily welded by SMAW/GMAW/SAW with weathering-matched consumables (e.g. E7018-W1/ER80S-G) so the weld patinas with the base; preheat 50–100 °C for thick or restrained joints and keep hydrogen low.
Can SMA490W be formed, bent or molded?
Hot-rolled plate bends cold at ≥3t inside radius across the rolling direction; hot forming is fine but avoid finishing below ~750 °C to protect toughness.
What surface finishes work on SMA490W?
Normally left bare to develop the protective patina — grit-blast to remove mill scale and design free-draining details; if painted, treat as ordinary structural steel with an epoxy/PU system, and manage rust runoff staining on adjacent concrete.
SMA490W 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 3114 SMA490 W/P | ≤ 0.18 | 0.13 |
| Si | 0.15 – 0.65 | 0.4 |
| Mn | ≤ 1.4 | 1.1 |
| PW type; P type allows 0.07–0.15 P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.01 |
| Cupatina former | 0.3 – 0.5 | 0.35 |
| Cr | 0.45 – 0.75 | 0.6 |
| Ni | 0.05 – 0.3 | 0.15 |
| Mooptional/residual | ≤ 0.1 | — |
| Voptional micro-alloy | ≤ 0.1 | — |
| Fe | balance | — |
SMA490W TMCP — frequently asked
What is SMA490W TMCP used for?
SMA490W TMCP is typically used for bridges, highway structures and exposed steel frameworks. In short: japanese weathering structural grade; maintenance-free bridge steel; A588-class atmospheric resistance.
What is the yield strength of SMA490W TMCP?
SMA490W TMCP has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is SMA490W TMCP easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Drills, saws and mills like A588/Q345 plate at ~60 % of 1212 speeds; use rigid setups and sharp carbide, expect mildly gummy chips from the higher Cu/Cr.
Can SMA490W TMCP be welded?
Yes — weldability is rated excellent (88/100). Readily welded by SMAW/GMAW/SAW with weathering-matched consumables (e.g. E7018-W1/ER80S-G) so the weld patinas with the base; preheat 50–100 °C for thick or restrained joints and keep hydrogen low.
What surface finishes work on SMA490W TMCP?
Normally left bare to develop the protective patina — grit-blast to remove mill scale and design free-draining details; if painted, treat as ordinary structural steel with an epoxy/PU system, and manage rust runoff staining on adjacent concrete.
Can SMA490W TMCP be formed, bent or molded?
Hot-rolled plate bends cold at ≥3t inside radius across the rolling direction; hot forming is fine but avoid finishing below ~750 °C to protect toughness.
What is the maximum service temperature of SMA490W TMCP?
SMA490W TMCP 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 SMA490W AR-HR and SMA490W-N?
AR-HR is the default condition — standard stocked condition for weathering-steel plate, strip and shapes up to moderate thickness. N: choose for thick plate or when guaranteed −5 °C/0 °C Charpy values and fine grain are specified. Yield strength is 390 MPa in AR-HR versus 380 MPa in N.
Sources
- JIS G 3114 — Hot-rolled atmospheric corrosion resisting steels for welded structures — JSA (2016)
- ASTM A588/A588M — High-Strength Low-Alloy Structural Steel with Atmospheric Corrosion Resistance — ASTM (2019)
- GB/T 4171 — Atmospheric corrosion resisting structural steel (Q355GNH) — SAC (2008)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13C — Corrosion: Environments and Industries (weathering steels) — ASM International (2006)
- Weathering steel plate (SMA490AW/BW/CW) datasheet — Nippon Steel (2022)
- Q355GNH/SMA490W — Mysteel / 1688 (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.