Why should the pressure vessel steel strictly limit its carbon content?

The pressure vessel steel should strictly limit its carbon content. It is because pressure vessels are under pressure and often contain toxic and flammable media. And it is made of tailor-welded steel plates, so the container steel is required to have good weldability. Carbon is the main element that affects the weldability of steel. When the carbon content increases, the weldability of steel significantly deteriorates, and the tendency to cracks increases rapidly. Therefore, in order to ensure the quality of the welded joint of the pressure vessel, the carbon content of the steel must be strictly controlled.