By means of the analyzing for the reason resulting in the welding crack in a strengthening tendon-plate of a pressure vessel,the article puts forward the method that has resolved the problem having common phenomenon in pressure vessel operation and has been proved to be effective through practical application in years.

By analyzing the effect of the material welding capability, welding structure, warm-up, heat treatment after welding and crafts parameter on welding crack in shore crane, the paper put forward the improving measure and acquires favorable result.

Through analysis on inside weld forming and welding procedure of SSAW pipe,it pointed out weld crack is easy to appear in brittle temperature zone in welding pool.

The hydrogenation pipe would weld crack after running for some time as high temperature and high pressure, and the phenomenon was rare.

By application of CO_2 arc welding on assembly and process of blast furnace stack casing,it prevent from welding distortion and crack efficiently,also it points out that enhancing welding quality needs observation and thinking over initially,and extending the application of CO_2 arc welding from cost,welding quality and training.