Effect of processing methods on microhardness and acid corrosion behavior of low-carbon steel

• Both ECAP and quenching strengthen the hot rolled steel.
• Strengthening effects of ECAP is better than that of quenching.
• Quenching enhances anti-corrosion and anodic passivation of the hot rolled steel.
• ECAP promotes anodic passivation but accelerated acid corrosion.
• Quenching is more suitable than ECAP for the steel used in acid.

Low-carbon steels with different microstructures were fabricated by hot rolling, quenching and equal-channel angular pressing (ECAP), respectively. Microhardness and acid corrosion behavior were evaluated, aiming to reasonably select an optimal processing method for the low-carbon steel used in a given environment. The results revealed that both ECAP and quenching improved the microhardness of the hot rolled steel, and the grain refinement strengthening effect by ECAP is better than the solid solution and phase transformation strengthening effect by quenching. The quenching process enhanced the acid corrosion resistance and anodic passivation property of the low-carbon steel, while the ECAP process promoted the anodic passivation but accelerated the acid corrosion rate. Quenching is more suitable than ECAP for strengthening the low-carbon steel used in an acid environment.