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Steel weld shrinkage prone to cracks reasons:

1. Layered make steel in the thickness direction tension performance deteriorated significantly, and may appear precision bright tubes interlayer tear weld contraction. Weld shrinkage induced local strain reaches the yield point strain often several times larger than the load caused by the strain;

2. Residual stresses caused by uneven cooling. The residual stress in the absence of external force internal self-equilibrium stress, hot-rolled steel has a variety of sections such residual stress, the greater the general steel cross-sectional dimension, the greater the residual stress. Although the residual stress is self-balanced, but still has some influence on the performance of the steel members under loads. Aspects such as deformation, stability, fatigue, etc. are likely to have an adverse effect

3. Hot-rolled steel products, poor control for precision light pipe thickness and edge width in this regard. We are familiar with thermal expansion and contraction, since the beginning of the hot rolling out even the length, thickness are standard, and finally cooled or there will be some negative difference, this negative differential edge width wider, more obvious as the thickness performance. So for large steel, steel edge for width, thickness, length, angle, and no law requires too precise edges.