| There has been great effort and development in producing the high strength steel to attain the best balance of cost reduction and properties. Recently, it has been suggested that a direct quench and temper process after hot rolling be the best method of producing linepipe steel. According to the suggested method, a comparably high carbon equivalent steel (0.16%C-1.33%Mn-0.024%Nb-0.052%V) was quenched and tempered after controlled-rolling. Microstructure was characterized by optical and transmission electron microscopy, and correlated with tensile property. Deformation bands, developed by heavy rolling below the recrystallization temperature, still exist at room temperature and have a bad effect on the property. This structure creates a twin-like diffraction pattern. Direct quench and temper method decreases the strain hardening rate and results in low tensile stress for the comparably high carbon equivalent steel. |
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