ERW直缝套管残余应力分布规律的研究

采用盲孔法配合计算机数据采集技术对 7种不同规格或状态的ERW直缝套管残余应力分布状态进行了测定。结果表明 ,ERW直缝套管上存在着较大的残余应力 ,个别区域的残余应力值达到材料的屈服极限 ,但焊缝及其附近区域的残余应力值较低 ;自然时效处理可以显著降低残余应力水平 ,特别是显著降低焊缝及其附近区域的残余应力水平 ,但其降低的程度与套管的直径大小有关 ,在相同条件下 ,小直径套管残余应力降低的幅度较大 ;在线热处理对其残余应力大小和分布的影响不明显 ,甚至有可能使焊缝及其附近区域应力水平升高 ;国产ERW直缝套管的残余应力水平与日本同类套管相当 ,可以替代同类进口产品。

Residual stress distribution regularity in ERW straight-seam casing tubet

The distribution of the residual stress in ERW straight-seam casing tube of seven kinds of sizes is determined by Mathar method in combination with data collection and processing by computer. The result shows that, influenced by the forming and welding process, there exists rather high residual stress on the surface of ERW straight-seam tube, the residual stress in one or two areas reaches the yield limit of the material, while the residual stress in seam and area near to the seam is fairly low. Natural aging treatment can reduce greatly the residual stress, but the reduction is related to the diameter of the casing tube, and the degree of the reduction of the residual stress in small-size casing tube is high at the same condition. The influence of on-line heat treatment on the residual stress and its distribution is unconspicuous. The residual stress value of the homemade ERW straight-seam casing tube is equivalent to those produced by Japan, therefore the homemade tube can be used instead of the imported products.