A comparative study of SM490A and SS400 steel plates was conducted focusing on their weldability under Gas Metal Arc Welding (GMAW), including observations on their microstructure, mechanical performance, and corrosion resistance.
The results indicate that after multi-pass welding, both the heat-affected zone (HAZ) and the root weld undergo effects similar to tempering or normalizing. This heat treatment process helps eliminate unfavorable microstructures-such as Widmanstätten ferrite-within these regions.
As a result, the toughness and hardness of the affected zones are significantly enhanced. The welded joints exhibit better impact resistance, mainly due to grain refinement. Meanwhile, the tensile strength of the welded steel increases proportionally with the level of heat input during welding.
Chemical Composition Comparison
| Alloy | C (%) | Mn (%) | P (%) | S (%) | Si (%) | Al (%) | Nb (%) |
|---|---|---|---|---|---|---|---|
| SM490A | 0.12 | 1.06 | 0.02 | 0.006 | 0.01 | 0.032 | 0.023 |
| SS400 | 0.16 | 0.76 | 0.012 | 0.007 | 0.01 | 0.041 | - |
Key Observation:
SM490A contains higher manganese and micro-alloying elements (such as Nb), contributing to better strength and toughness compared to SS400.
Mechanical Property Comparison
| Steel Grade | Tensile Strength (MPa) | Elongation (%) |
|---|---|---|
| SM490A | 460 | 30.3 |
| SS400 | 537 | 17.3 |
SM490A shows greater ductility (higher elongation) and more stable toughness, making it suitable for welded structural applications requiring shock and vibration resistance.
SS400 provides higher tensile strength, but lower elongation, meaning it is less resistant to deformation and may be more brittle compared to SM490A.
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We have a professional technical team capable of providing support for material selection, welding solutions, and application recommendations for both SM490A and SS400 steel plates. We value integrity, consistent quality, and long-term cooperation, and have built strong partnerships with customers around the world.
If you are interested in SM490A or SS400 steel plates, please feel free to contact us. We look forward to becoming your reliable supplier.
