Effect of Hot Working Processes on Microstructure and Mechanical Properties of Pipeline Steel

The microstructure and microhardness of X70 pipeline steel were investigated after conducting different processing routes. was characterized using optical electron microscopy. Scanning microscopy equipped with backscattered diffraction (EBSD) transmission techniques applied for investigation thermal treatment conditions. Mechanical properties by a tester. results show that the mainly consists granular bainite, acicular ferrite small amount M/A constituents under hot rolling states. There are many dislocations inside ferrite. simulation experiments becomes homogeneous increase in cooling rate. morphology fine uniform, content increases at same compression amount. gives rise to accumulated strain stored energy, which accelerate transformation refine steel. rises deformation ratio subjected isothermal quenching process is ultrafine islands. When temperature reaches 550 °C, upper bainite appears microstructure. With temperature, decreases. Acicular better candidate than steels.