Effect of post weld heat treatment on mechanical properties of MIG welded mild steel

In railway locomotive, fabricated bogie frame structures are susceptible to crack when made up of un-heat-treated and heat-treated structure. Therefore, variation in behaviour of the samples made of the same material in both the conditions, that is, PWHT and un-heat-treated is important to quantify and analyse. In the present work, specimens from IS 2062 E410 are prepared as per standard weld procedure specification using MIG welding and half of the welded samples are heat-treated following a predefined heat treatment procedure. The samples are tested to find out their mechanical properties like hardness, toughness, tensile strength and microstructure of HAZ. Refined grain structure and significant improvement in mechanical properties of the specimen are observed in the samples undergone post-weld heat treatment.