A350 LF3钢管道法兰的热处理工艺和力学性能

Heat Treatment Processes and Resulting Mechanical Properties of A350 LF3 Steel Pipe Flanges

尺寸不同的A350 LF3钢盲板法兰和对焊法兰需进行调质处理,以使其满足力学性能要求。除了优化钢的化学成分以外,为确定合适的调质处理工艺,采用A350 LF3钢试块I进行了热处理工艺试验,即900℃空冷正火、880℃水淬和650℃回火。结果,试块I的力学性能满足要求,但断后伸长率刚刚合格。为此,将A350 LF3钢试块Ⅱ的调质处理工艺调整为850℃水淬和670℃回火。结果表明,试块Ⅱ的拉伸性能和-101℃冲击韧度均满足要求。两种法兰采用调整后的工艺调质处理后,力学性能均符合要求。

Blind flange and butt welded flange differing in size,made of A350 LF3 steel,need to be quenched and tempered to cause them to exhibit mechanical properties which conform with the requirements.In order to identify an appropriate quenching and tempering processes,trial heat treating processes,that is,normalizing consisting of heating at 900℃ and air-cooling,quenching from 880℃ in water and tempering at 650℃,was carried out by A350 LF3 steel test block I,in addition to optimizing composition of the steel.As a result,the test block I exhibited desired mechanical properties,however,its elongation was just qualified.For this reason,the quenching and tempering processes for the A350 LF3 steel test block Ⅱ were adjusted to quenching from 850℃ in water and then tempering at 670℃.The results indicated that tensile properties and impact toughness at-101℃ of the test block Ⅱ all conformed with the requirements,and mechanical properties of the two categories of flanges quenched and tempered by the adjusted processes all reached the requirements.