HEAT TREATMENT AND METHODS TO IMPROVE THE CORROSION RESISTANCE AND HARDNESS OF STEEL

Hossam Ibrahim Al-Itawi (Jordan) and Firas Al-Quran (Jordan)

Received May 16, 2009; Revised July 4, 2009

Abstract

In this work, the effect of heat treatment process of spheroidal intermediate annealing on corrosion resistance and microhardness is studied. For this purpose low composition of chromium-nickel steel was chosen. Samples of this steel were carburized, normalized, annealed, hardened and tempered. All results were compared with samples passed the same heat treatment processes but without annealing. It was shown that the hardness of the material is affected by annealing time and temperature with no obvious pattern. The best result of microhardness showed samples annealed at  for 60 min holding time, where it was 50.4HRC (increased about 30%). Corrosion resistance was measured by weight loss in 0.1M HCl acidic solution. Almost all samples show a decrease in weight loss. This decrease in weight loss increases with time. The best result of corrosion resistance showed samples annealed at  45 min holding time.

Keywords and phrases: corrosion, resistance, microhardness, microstructure, weight loss, intermediate annealing, spheroidal annealing.