[Z" Steel Z25

Steel after hot rolling, steel ingot form when bubbles, defects such as cracks and loose, can in the high temperature and pressure under the action of weld, and refine grain steel enable close-grained, mechanical performance is improved.This improvement is mainly manifested on along the rolling direction, steel is no longer isotropic body in three directions, the inside of the steel non-metallic inclusions (mainly sulfide, silicate and oxide) is pressed into sheet or strips, appear statified phenomenon (sandwich).Layered make steel along the thickness direction tensile performance is much worse, and may in the weld shrinkage occurs when torn between the layers.High-rise building beam-column node rigidity, column flange plate thickness direction pulling force and inside and outside the shrinkage stress of weld, when the column flange plate thicker, torn between the layers and risk is more likely.
Steel plate thickness direction performance levels and the reduction of area average and single value shall comply with the provisions of the table 2.