Effect of Mechanical Surface Treatments on Impact Strength for Low Carbon Steel AISI 1020

Abstract

Objective of this paper is to study the influence of some mechanical surface treatments on impact strength stress for low carbon steel AISI 1020 AISI. Several specimens were subjected or encountered to for impact test were equipped agreeing to ASTM E23 and then were encounter to surface treatment Such as shot peening which was implemented on some specimens using steel balls having diameter of 1.25mm and hardness = 55HRC for (10,20,30) min. Some another’s specimens were treated with using laser peening pulse in notch zone of impact specimen at (5,10,15) laser CO2 pulse. and Plasma also used for surface treatment of impact specimens by using plasma beam for 2,5,10 sec. The results showed that the mechanical surface treatment contributed in improvements of toughness fracture for low carbon steel comparing with base metal. It was found that when increasing shot peening time finding decreasing in the impact strength decreased impact stress because of increase in hardness which generating from heat shot which generated residual stress and the best time was 10 min. and laser pulses and plasma beam were in contributed in increasing impact strength stress for the same reason above and the number of 5 pulse give gave the best result and also the plasma for 5 sec.