一种石油天然气开采用80钢级膨胀管的性能研究

Study on Properties of 80 Steel Expandable Tube for Oil and Gas Exploitation Service

从显微组织、硬度、残余应力、力学性能、外压与内压失效性能等方面,分析了利用SEW工艺研发的80钢级膨胀管的综合性能.结果表明：开发的80钢级膨胀管的显微组织为铁素体＋回火索氏体;经膨胀率为16.50％的膨胀变形后,管材的屈服强度为640～650 MPa,抗拉强度为725～735 MPa,伸长率为18.5％～20.5％,焊缝横向（1/2尺寸,0℃）冲击功达到56～60 J,抗外压挤毁强度超API RP 5C3标准要求值18％,静水压强度超API Spec 5CT标准要求值88％,综合力学性能良好。

The over-all properties of the 80 steel expandable tube as developed with the SEW process are analyzed, involving such properties as microstructure, hardness, residual stress, mechanical properties, and external pressure/internal pressure failure, etc. The results reveal the facts as follows. The microstructure of the said tube is composed of ferrite and tempered sorbite. After being deformed via expansion with expansion rate of 16.50%, the tube presents such mechanical properties as yield strength： 640～650 MPa, tensile strength： 725～735 MPa, elongation： 18.5%～20.5%, transversal impact toughness of the weld （size： 1/2 and temperature： 0 ℃） ： 56～60 J, external pressure collapse strength： over the standard 18% as required by API RP 5C3, and hydrostatic pressure strength： over the standard 88% as specified by API Spec 5CT. All the above mentioned data demonstrate that the 80 steel expandable tube is in possession of excellent over-all mechanical properties.