Increased Yield & Tensile Strength via Work Hardening
Cold rolling compresses and rearranges the internal grain structure of SPA-H at room temperature, introducing residual internal stress to strengthen the material. Per JIS G 3125, hot-rolled SPA-H has a minimum yield strength of 345 MPa and minimum tensile strength of 480 MPa. After secondary cold working, the yield and tensile strength of SPA-H will generally increase by 20–30%. Cold-worked SPA-H features stronger anti-deformation and anti-impact capacity, suitable for thin flat precision parts that require high rigidity.
Elevated Surface Hardness
Grain compaction from cold working hardens SPA-H's surface. Cold-worked SPA-H delivers better scratch and abrasion resistance compared to as-hot-rolled SPA-H, which is an advantage for flat decorative sign panels and industrial equipment enclosures.
Reduced Ductility & Elongation at Break
Grain distortion generated by cold rolling limits SPA-H's plastic stretching capacity. After cold working, the ductility of SPA-H decreases significantly, impairing its formability. Cold-worked SPA-H cannot withstand sharp small-radius bends, deep drawing or complex three-dimensional forming, as these processing methods carry a high risk of cracking. It is only applicable to flat SPA-H panels or gentle bending with large radii.
Improved Dimensional Precision & Flatness
Hot-rolled SPA-H naturally has minor thickness deviation and surface warpage. Cold rolling adopts precise roller clearance control to process SPA-H into sheets with uniform thickness and good flatness. This high dimensional accuracy meets the requirements of laser-cut decorative lettering and precision industrial casings made of SPA-H.
No Impact on Toughness in Ambient Conditions
Cold rolling does not significantly reduce the steel's toughness (resistance to fracture) at room temperature, so cold-rolled SPA-H still performs well in most outdoor ambient environments.
Toughness may decrease slightly at very low temperatures, but this is rarely a concern for its typical thin-gauge applications.
