In order to study the change of fracture toughness owing to post weld heat treatment of welded specimens under the elastic bending deformation, after post weld heat treating of four different conditions, that holding time is 0, 1/4hr, 1hr and 10hr, on...
In order to study the change of fracture toughness owing to post weld heat treatment of welded specimens under the elastic bending deformation, after post weld heat treating of four different conditions, that holding time is 0, 1/4hr, 1hr and 10hr, on the welding joint of the high strength steel with bead on plate, tested the low temperature fracture toughness, observed the microstructure and measurred the microhardness.
We obtained the results as follows.
1. Fracture toughness depends upon the heat treatment conditions.
2. Fracture toughness of the specimen under the pre-strain remarkablly increased until the holding time of the heat treatment is one hour, but it was almost saturated over the one hour.
3. Tempering the welding HAZ with the maximum (H_v=250), it became soft to H_v=170, but tempering under the elastic straining (ε=0.024), increased the hardness to the H_v=210.
4. Tempering at the condition of the elastic strain on the HAZ structure, fracture toughness greatly depends upon the hot working deformation.