Steel SM490A TMCP
Supply condition
JIS SM490A · ASTM A572 Gr 50
TMCP = thermomechanically controlled processed
Choose for thick bridge/offshore plate where low carbon equivalent, better weldability and higher toughness are needed at the same strength.
Values for the TMCP condition
Other SM490A tempers and conditions
SM490A is listed in 4 conditions; see the grade overview at SM490A.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stress relieved | Use for heavy welded fabrications needing dimensional stability and reduced residual stress before machining. | 350 | 520 | 25 | 148 HB | 10 % IACS |
Normalized | Pick for thick plate or after hot forming when uniform fine grain and better notch toughness are required. | 360 | 530 | 25 | 150 HB | 10 % IACS |
ARDefault As hot rolled | Standard stocked plate/section condition for general welded structures at ambient service temperature. | 365 | 540 | 22 | 155 HB | 10 % IACS |
TMCPThis page Thermomechanically controlled processed | Choose for thick bridge/offshore plate where low carbon equivalent, better weldability and higher toughness are needed at the same strength. | 385 | 545 | 24 | 160 HB | 10 % IACS |
What is SM490A TMCP?
SM490A TMCP is SM490A supplied in the TMCP condition — choose for thick bridge/offshore plate where low carbon equivalent, better weldability and higher toughness are needed at the same strength. SM490A TMCP has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 545 MPa (79 ksi) — weaker than 65% of steel grades. Elongation at break is 24% and the elastic modulus is 205 GPa (29.7 Msi). SM490A TMCP has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). AR is the default condition FabDigit quotes; TMCP is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 155 MPa·√m (141.1 ksi·√in), better than 97% of steel grades
- Readily welded — 93/100, better than 95% of steel grades
- Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Forms and bends easily — 66/100, better than 83% of steel grades
Limitations
- Hard to polish — 40/100, worse than 96% of steel grades
SM490A TMCP properties
Typical room-temperature values for SM490A TMCP; 23 are specific to this condition. Other listed values are SM490A reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SM490A TMCP has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
SM490A TMCP has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 545 MPa (79 ksi) — weaker than 65% of steel grades. Elongation at break is 24% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SM490A TMCP is rated for continuous service to 350°C (662 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
SM490A TMCP conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of SM490A TMCP takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
SM490A TMCP's machinability is good (56/100, better than 71% of steel grades); weldability excellent (93/100); formability good (66/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SM490A TMCP
Is SM490A easy to machine?
Machines like ordinary C-Mn structural steel at ~60 % of AISI 1212; use rigid setups and coolant, expect stringy chips in as-rolled plate.
Can SM490A be welded?
Excellent weldability by SMAW/GMAW/SAW with ~E49xx / ER70S-class consumables; preheat 50–100 °C for thick sections or high restraint.
Can SM490A be formed, bent or molded?
Cold bend at r ≥ 2t (≥3t across the rolling direction for thick plate); hot forming 900–1050 °C followed by normalizing is preferred for tight radii.
What surface finishes work on SM490A?
Must be protected — blast to Sa 2½ then epoxy/zinc-rich primer, hot-dip galvanize, or metallize; no anodizing, polishing is only for cosmetic ground plate.
SM490A 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 |
|---|---|---|
| C≤0.20 for t≤50 mm; ≤0.22 for t>50 mm (JIS G3106) | ≤ 0.2 | 0.16 |
| Si | ≤ 0.55 | 0.3 |
| Mn≤1.65 (older editions 1.60); ≥0.60 for shapes | ≤ 1.65 | 1.35 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Fe | balance | — |
SM490A TMCP — frequently asked
What is SM490A TMCP used for?
SM490A TMCP is typically used for bridges, heavy structures, cranes and shipbuilding. In short: A572 Gr 50 equivalent; weldable at 365 MPa yield; needs preheat when thick.
What is the yield strength of SM490A TMCP?
SM490A TMCP has a typical yield strength of 385 MPa (55.8 ksi) and a tensile strength of 545 MPa (79 ksi) — weaker than 65% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is SM490A TMCP easy to machine?
Reasonably — machinability is rated good (56/100, better than 71% of steel grades). Machines like ordinary C-Mn structural steel at ~60 % of AISI 1212; use rigid setups and coolant, expect stringy chips in as-rolled plate.
Can SM490A TMCP be welded?
Yes — weldability is rated excellent (93/100). Excellent weldability by SMAW/GMAW/SAW with ~E49xx / ER70S-class consumables; preheat 50–100 °C for thick sections or high restraint.
What surface finishes work on SM490A TMCP?
Must be protected — blast to Sa 2½ then epoxy/zinc-rich primer, hot-dip galvanize, or metallize; no anodizing, polishing is only for cosmetic ground plate.
Can SM490A TMCP be formed, bent or molded?
Cold bend at r ≥ 2t (≥3t across the rolling direction for thick plate); hot forming 900–1050 °C followed by normalizing is preferred for tight radii.
What is the maximum service temperature of SM490A TMCP?
SM490A 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 SM490A-AR and SM490A TMCP?
AR is the default condition — standard stocked plate/section condition for general welded structures at ambient service temperature. TMCP: choose for thick bridge/offshore plate where low carbon equivalent, better weldability and higher toughness are needed at the same strength. Yield strength is 365 MPa in AR versus 385 MPa in TMCP.
Sources
- JIS G3106 Rolled steels for welded structure — JSA (2020)
- ASTM A572/A572M Grade 50 — ASTM (2021)
- GB/T 1591 Q345B / Q355B — SAC (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Heavy plate for welded structures (SM490 series) — Nippon Steel / JFE Steel (2022)
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.