Development of Mo,Cu,Ni free X65MOS submarine acid resistant pipeline steel
In response to the high cost of X65M submarine acid resistant pipeline steel,a low-cost X65MOS hot-rolled strip that meets the mechanical properties,aging impact property,CTOD performance,HIC and SSCC resistance performance require-ments of submarine acid resistant pipelines was developed using a reasonable TMCP process design without adding Mo,Cu,Ni elements in the chemical composition.Production practice has proven that under low-temperature rolling conditions,increasing the reduction rate of the final stand to 13％,and using ultra fast cooling and dense laminar cooling processes,the needle like fer-rite grains of X65MOS strip were refined to a grain size of grade 12,significantly improving its mechanical properties.The re-sults of the drop hammer experiment showed that the shear tear area of X65MOS strip reached 100％at-40 ℃,and the aging impact energy reached over 300 J at-60 ℃,with a CTOD value of+oo.Under the same HIC and SSCC test conditions,when there were many cracks in the X65M strip,there were no cracks in the X65MOS strip.The large number of dislocations in the microstructure of the X65MOS strip ensured its CTOD performance,HIC and SSCC resistance performance in the absence of Mo,Cu,and Ni elements.The low-cost X65MOS strip developed has significantly better performance than X65M strip,which has important practical significance for enhancing product competitiveness and improving economic benefits.
NETL
NSTL
万方数据
