Stainless steel and carbon steel has many similarities

Boom is , the lower rib arch bridge to connect a critical component of the deck , the deck dead load and live load boom passed through rib , vehicles, wind ( rain ) , the earthquake causes  Valve manifolds  by the alternating stress far below the boom in the case of static strength fatigue failure may occur . Tianjin urban area in the construction of a three-span continuous steel arch bridge span arrangement of 51m +55 m +51 m, a length of 157m. For aesthetics , the bridge uses a new type of threaded connection includes stainless steel boom , boom is not due to this new  High pressure ball valve  steel used in the actual project experience , so it needs to be a special anti-fatigue properties. For stainless steel component performance and design of the study has been widely carried out . Research shows that  Instrumentation ball valve  steel and carbon steel has many similarities, but there are many different , making the design needs to be treated differently, such as carbon steel and low alloy proportional limit of at least 70% of the yield strength , and the stainless steel yield strength proportional limit of about 36 % and 60%. United States, Europe and Australia issued a stainless steel structure design specifications . Threaded connections in the project has been widely used , since the thread will produce stress concentration , and therefore under cyclic loading , it is easy to fatigue in threaded connections .