采用化学成分分析、拉伸和冲击性能测试、金相检验等方法分析了偏析对S690高强度无缝钢管性能的影响；再对焊接后无缝钢管进行侧面弯曲、横向拉伸、焊缝冲击试验及金相检验，分析了偏析对无缝钢管焊接工艺评定的影响。结果表明：S690高强度无缝钢管内表面存在明显的碳化物带状偏析，导致碳含量和碳当量偏高；偏析使无缝钢管内表面的冲击吸收能量偏低；偏析使根部熔合线处形成粗大的富碳马氏体+残余奥氏体、魏氏体组织，同时颗粒状贝氏体沿晶界析出，导致材料的冲击韧性降低。

The effect of segregation on the properties of S690 high strength seamless steel tube was analyzed by means of chemical composition analysis, tensile and impact properties test and metallographic examination. Then, the side bending, transverse tensile, weld impact test and metallographic examination of the welded seamless steel tube were carried out, and the influence of segregation on the welding procedure qualification of the seamless steel tube was analyzed. The results show that there was obvious carbide band segregation on the inner surface of S690 high strength seamless steel tube, which led to high carbon content and carbon equivalent. Segregation made the impact absorption energy of the seamless steel tube inner surface low; segregation caused the formation of coarse carbon-rich martensite+retained austenite and widmanstatten structure at the root fusion line, and granular bainite precipitated along the grain boundary, resulting in a decrease in impact toughness of the material.