Properties and homogeneity of 550-MPa grade TMCP steel for ship hull

由有更少的 Ni ， Cr ，和瞬间内容的热机械控制 processTMCP 的极端低碳钢为 550 MPa 等级被开发了重计量器轮船壳并且近海在微观结构之中的 structures.The 关系，进程，并且学习的钢的性质是精确控制技术的 investigated.A 系列为这种 steel.Cu microalloying 和 TMCPrelaxation 降水 controlRPCaccelerated

Ultra low carbon steels by the thermal mechanical control process（TMCP） with less Ni,Cr,and Mo contents have been developed for 550 MPa grade heavy gauge ship hulls and offshore structures.The relationships among microstructures,process,and properties of the studied steel have been investigated.A series of accurate control technologies have been developed for this kind of steel.Cu microalloying and TMCP＋relaxation precipitation control（RPC）＋accelerated cooling process were employed to optimize the mechanical properties and ensure the homogeneity of the 80-mm thick plate.The microstructures of thin plates slightly changed from surface to center,but the micro-structures of the heavy gauge plate（80 mm） changed notably.Adopting the simple composition,it can meet the requirement of thin plates by adopting a few microalloys.As for thick plates（80 mm）,a little higher Cu and Ni contents should be adopted.These steels can meet the needs without tempering.By these ways,the properties of the steels can be optimized,and the cost can be decreased notably.