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A516 Gr70 vessel steel plate after welding heat treatment properties

BBN studied the effects of different simulated post-weld heat treatment cycles on the strength and impact properties of A516 Gr70 vessel steel plate. With the increase of the number of simulated post-weld heat treatment cycles, the yield strength and tensile strength of A516 Gr70 vessel steel plate showed a downward trend; the ductile-brittle transition temperature (VTE) moved to the high temperature direction.

After simulated post-weld heat treatment, the microstructure of A516 Gr70 vessel steel plate is ferrite + pearlite band structure, the band in pearlite is partially ablated, and the cementite tends to spheroidize. Cementite can be seen at the ferrite grain boundary.

With the increase of simulated PWHT cycles, the yield strength and tensile strength of A516 Gr70 vessel steel plate decreased, which was due to the increase of ferrite grain size and the coarsening of pearlite layers.