TMCP Steels

TMCP Steels TMCP stands for Thermo Mechanical Control Process and TMCP steels are those steels which are produced by this process. TMCP is a microstructural control technique combining controlled rolling (thermo mechanical rolling) and controlled cooling (accelerated cooling). These steels are sometimes microalloyed. Thermo mechanical control process is normally used to obtain excellent properties for steel plates such as high strength, excellent toughness along with excellent weldability through maximizing of grain refinement. These steels have almost same formability and weldability compared with mild steels. The superior mechanical properties introduced to the steel through this processing route are virtually equivalent to those obtained by heat treating conventionally rolled or forged steel and hence Thermo mechanical control process is used as a substitute for heat treatments that require additional material handling and furnace facilities. TMCP technology was developed early in 1980s and major Japanese plate rolling mills have started to produce TMCP steels by middle of 1980s. TMCP steels production When TMCP is chosen as the process route, the input material (i.e. the slab) is heated to a temperature regularly used for hot rolling operations (around 1200 deg C). The roughing operation during rolling in the rolling mill is carried out in a normal way, but the finish rolling is carried out at a lower temperature (around 750 deg C to 800 deg C) than the temperatures used in a normal rolling process. Plastic deformation at this lower temperature promotes fine grain sizes and retards precipitation. The final hot working may continue down to temperatures below the critical temperature of transformation from austenite to ferrite. This requires heavy rolling equipment capable of deforming the steel at low hot working temperatures. The optimum precipitate size and dispersion is obtained when the finish rolling temperature is around 775...