材料期刊网

以ITERTF316LN奥氏体不锈钢无缝管为研究对象，研究了焊接、8％冷变形和650℃、200h的老化处理对316LN不锈钢管性能的影响。分别取母材、焊接接头、经过冷变形和老化处理的焊接接头进行了室温和液氦温度4．2K下的拉伸和冲击性能的研究，并利用扫描电镜对拉伸和冲击断口的微观形貌进行了观察。结果表明，母材、焊接接头和经过冷变形和老化处理的焊接接头在4．2K的断后伸长率和冲击韧性依次降低，经过冷变形和老化处理的焊接接头相比母材和未经过任何处理的焊接接头的抗拉强度和屈服强度均高出50～60MPa。4．2K下，母材的断后伸长率由室温下的48％下降到44％，相反的，焊接接头和经过变形和老化处理的焊接接头的断后伸长率却分别由37％和23％上升到了41％和38％；3种样品在4．2K下的抗拉强度和屈服强度均是室温下的2～3倍。

Based on the ITER TF 316LN austenitic stainless steel tubes, the influence of welding, 8% cold working and 200 h aging at 650℃ on the 316LN austenitic stainless steel tubes were investigated. The test samples were sampled from the base metal, the welded tube and the welded tube with the treatment of cold working and aging. Their tensile and impact properties were tested at room temperature and 4.2 K, and the tensile and impact fracture surfaces were observed by scanning electron microscopy morphology （SEM）. The results show that the elongation and impact toughness decrease in turn of the base metal, the welded joint and the welded joint with the treatment of cold working and aging, the yield strength of the welded joint after deformation and aging treatment are higher than the welded joint without any treatment and the base metal about 50--60 MPa. The base metal＇s elongation after failure at 4.2 K decreases to 44% from 48% at room temperature, on the contrary, the elongation after failure of the welded joint and the welded joint with the treatment of cold working and aging increase to 41% and 38% from 37% and 23%, respectively. Three kinds of test samples＇ strength are all high at 4.2K, and the ultimate tensile strength and 0.2% off-set yield strength are two to three times higher than at room temperature.