The acceptance specifications of steel castings have realized that the outer surface of steel castings is more important, because the cast steel joints are mainly controlled by bending load, and the outer wall defects are more likely to have adverse effects under bending load, which should be paid special attention. In addition, the casting defects on the surface of steel castings are easy to gradually expand due to corrosion during use, and then penetrate the steel castings, resulting in serious consequences. However, the above specifications do not further divide the stress zone of steel castings. For example, the casting defects in the weld affected zone should be paid more attention, because the casting defects may be more dangerous under the action of weld residual stress.
To sum up, the main features of national norms are as follows:
(1) Chinese standard gb7233-09 mainly draws lessons from European Code en12680-1;
(2) American specification astm-609 / 609m has its own characteristics, emphasizes the concept of dense defects, and has more restrictions on the casting process;
(3) Unlike the casting defect evaluation of special equipment, these specifications almost do not involve the impact of defects on the mechanical properties of castings. Only German specifications allow cracks.