X70级管线钢硫化物应力腐蚀开裂行为研究

RESISTANCE OF X70 PIPELINE STEEL TO SULFIDE STRESS CORROSION CRACKING

用三点弯曲方法及SEM、TEM等手段研究了不同组织类型的X70级管线钢硫化物应力腐蚀开裂(SSCC)行为。结果表明,显微组织以均匀细小的针状铁素体为主的管线钢具有优良的抗SSCC性能;这主要是源于针状铁素体内高密度缠结的位错和碳氮化物在位错网络上的沉淀析出起到了强烈的氢陷阱作用。

Using the NACE standard bent-beam test, sulfide stress corrosion cracking （SSCC） of different types microstructure in X70 grade pipeline steel with different types of microstructure was investigated. The X70 pipeline steel are all obtained from Ansteel, The result showed that the X70 pipeline steel had the excellent performance to the SSCC and the microstructure dominated by fine and homogeneous acicular ferrite had the excellent resistance to SSCC. Both the high density tangled dislocation and carbonitride precipitiated along with dislocation networks are the main reasons for the steel with acicular ferrite to have excellent resistance to SSCC. The microstructure is the main factor to decide the SSCC performance.