The high strength steel containing vanadium Q960E was hot-rolled and quenched at 900℃,and it was subjected to induction tempering at 450,550 and 600℃,respectively.By means of scanning electron microscope(SEM)and projection electron microscope(TEM),the microstructure characteristics of Q960E steel at different temperature of induction tempering were studied.The results show that the microstructure of Q960E steel plate after quenching is martensite+bainite complex structure,and the shape quality before induction tempering is ensured by increasing the final rolling and crimping temperature.After high temperature tempering,the microstructure is tempered sorbite.By the addition of V,the precipitate phase of<100 nm is uniformly dispersed during the induction tempering process.The plate strength after induction high temperature tempering is guaranteed.And with the increase of tempering temperature,the partial tempering martensite disappears and the tempering sorbite structure is formed.The best mechanical properties of Q960E can be obtained by high frequency induction tempering at 900℃/15 min,(550-600℃)/15 min,the transverse strength fluctuation of the pass coil is<10 MPa,and the longitudinal strength fluctuation range of the pass coil is<30 MPa.Transverse and longitudinal elongation are stable at more than 12％.
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