Experimental simulation research on TMCP of 30MnCr22 oil well pipe

Abstract Thermo-mechanical controlled process (TMCP) of 30MnCr22 oil well pipes was investigated by experimental simulation. The results showed that controlled rolling of TMCP effectively exerted the comprehensive effects of grains refinement by recrystallization in piercing and continuous rolling and deformation strengthening by strains accumulation in the non-recrystallization zone of reducing deformation. And the key point of TMCP is that quenching realized the microstructural heritability of fine and strengthened austenite, which achieved the best refinement of martensite laths to be 170 nm, nanoscale carbides with the average size of 101 nm and dislocations with the high-density of 8.38 × 10⁹ mm⁻², presenting a kind of complicated multi-layer microstructural characteristics. Finally, the synergistic strengthening effects on fine grain strengthening, laths refinement strengthening, dislocation strengthening and precipitation strengthening were realized by TMCP. Further, the synergistic strengthening mechanisms are explored to be that quenching enforced the interaction between martensite laths and dislocations, as well as the entanglement between θ-(Fe, Cr)₃C and dislocations.