Though electron beam welding (EBW) causes minimum destruction to the base metal, significantly different microstructure exists at weld zone. Rapid heating and cooling during electron beam welding results in dendritic microstructure, which lowers mechanical properties. In order to recover the original mechanical properties, post weld heat treatments (PWHT) needs to be performed after EBW. This paper presents effect of PWHTs on mechanical and microstructural properties of electron beam welded SAE 5137 H steel. Welded steel plates were processed through different heat treatments like stress relieving, normalizing and hardening & tempering. Micro-structural and mechanical testing were performed to characterize these specimens. It was perceived that, different PWHT’s can be employed and selection depends on final mechanical property requirement from the weld joint.

In the recent years, there has been a remarkable increase in the use of deep cryogenic treatment (DCT) for enhancing performance of tool steels. It is a supplementary treatment where components are treated below subzero temperatures for several cryo-soaking hours. This paper focuses on to study the effect of deep cryogenic treatment and cryo-soaking time on microstructural and mechanical properties of AISI H-13 tool steel. Deep cryogenic treatment at different cryo-soaking time (16-48 hours) were applied and tool steel performance was analyzed by using mechanical, fatigue and wear testings. The microstructural evolutions during DCT were evaluated by using scanning electron microscope (SEM). It was observed that microstructural modifications like increase in carbide density, fine and uniform martensitic structure during DCT had significantly improved properties which were influenced by cryo-soaking time.