在油气输送管线用钢管制造过程中，钢管的屈服强度有所损失，即包申格效应。本文研究了采用JCOE工艺生产直缝埋弧焊管的包申格效应。通过对X65与X70两种钢级不同规格的钢板及其相对应的钢管母材进行拉伸性能试验，测得X65与X70两种钢级钢板及其相对应钢管的屈服强度、抗拉强度、伸长率和屈强比，分析并得出如下结论： 1. 对X70钢级Ø1016×21mm钢管及其对应的钢板：随着实测钢板屈服强度的升高，其包申格效应也越大；而当钢管的实测屈服强度的较高时，表现出较小的包申格效应；随着钢板屈强比的增加，包申格效应也相应增大；当钢板实测抗拉强度的较高时，与之相对应钢管的实测抗拉强度也较高。 2. X65钢级直缝埋弧焊接钢管实测屈服强度较其钢板有所增加，Ø511.2×15.9mm钢管平均屈服强度增加约50MPa，Ø508×14.3mm钢管平均屈服强度增加约30MPa。即该规格钢管的包申格效应不明显，这是由于钢管口径小，成型过程中形变量较大，形变强化效应大于包申格效应。 3. X70级Ø1016×17.5mm钢管实测平均屈服强度较其钢板有所增加，增加的幅度大约为15MPa左右；而X70级Ø1016×21mm钢管实测平均屈服强度较其钢板有所减少，减少大约6MPa，表现出包申格效应。 4. 通过对X65与X70钢级钢板和钢管屈服强度实测值的比较，可得钢级越高，包申格效应越明显。 5. X65钢级 508×14.3mm钢管及其钢板，纵向平均屈服强度均比横向的高出约15MPa。

During the manufacturing of the pipe for oil and gas pipeline, the Yield Strength of pipe was decreased, which was called the Bauschinger Effect. The Bauschinger Effect of Longitudinal-seem Submerged-Arc Welded (LSAW) Line Pipe made by JCOE Forming Process was studied in this paper. By the Tensile Test of the plate and its corresponding pipe in different size of X65 grade and X70 grade, the Yield Strength (σs0.5), Ultimate Tensile Strength (σb), Rate of Elongation and the rate of Yield Strength to Ultimate Tensile Strength (σs0.5/σb) of the plate and its corresponding pipe were tested, by analyzing the test results the conclusions were drew as follows: 1. As for the X70 grade Ø1016×21mm pipe and its corresponding plate, the higher tested Yield Strength of plate, the lower Bauschinger Effect for its pipe; while the higher the tested Yield Strength of pipe, the smaller Bauschinger Effect it showed; the higher tested rate of Yield Strength to Ultimate Tensile Strength, also the greater Bauschinger Effect; and the higher tested Ultimate Tensile Strength of plate induced to the higher tested Ultimate Tensile Strength; 2. As for the X65 grade Ø511.2×15.9mm Longitudinal-seem Submerged-Arc Welded(LSAW) Line Pipe, the average tested Yield Strength was 50MPa more than its corresponding plate; and so did the X65 grade Ø508×14.3mm pipe, 30MPa more than the average tested Yield Strength of its corresponding plate. That was to say, the Bauschinger Effect was not visible for pipe of this size because it was less than the Deformation Strengthen Effect result from the small outside diameter of pipe and much deformation during forming process; 3. As to the average tested Yield Strength of the X70 grade Ø1016×17.5mm pipe was increased by 15MPa than its corresponding plate; While for the X70 grade Ø1016×21mm pipe, the average tested Yield Strength was 6MPa less than its corresponding plate, which was the Bauschinger Effect; 4. By contrast of the Yield Strength of the plate and its corresponding pipe in different size of X65 grade and X70 grade, those pipe with higher grade have more obviously Bauschinger Effect; 5. Both the X65 grade Ø511.2×15.9mm Pipe and its corresponding plate, the average tested longitudinal Yield Strength was nearly 15MPa more than its transverse Yield Strength.