The influence of chemical composition on structure of plate X100 after physical simulations of finishing rolling process with accelerated cooling

The research presented in the current paper was carried out for the experimental steel designed for plate which meets the requirements for grade X100 according to API5L. The tested steel is fine-grained constructional steel for making tubes for gas pipelines with minimal yield point of 690 MPa and tensile strength over 760 MPa. The laboratory tests were obtained that in the structure the polygonal ferrite were observed. That may have a disadvantageous influence on the limit of plasticity value X100 steel. The corrections of the chemical composition were carried out. The temperature and deformation schemes in the thermo-plastic treatment phase were determined.