In the article, I will give you a detailed introduction to the factors that affect the quality of sch40 astm a511 mt304 seamless stainless steel pipe, let's take a look!
1. The sch40 astm a511 mt304 seamless stainless steel pipe billet is supplied with molten steel by an electric arc furnace or an intermediate frequency furnace, and then refined in an AOD furnace. In the AOD furnace, it is boiled by blowing oxygen and decarburizing, so that the gas inclusions in the molten steel float to the slag layer. In actual operation, sometimes more oxygen is blown, and ferrosilicon is added to reduce, but more silica inclusions are produced.
2. Sch40 astm a511 mt304 seamless stainless steel pipe adopts round tube billet for two-roll skew rolling and piercing, and the metal flows outward to form holes during skew rolling. When the roll speed is too fast, the hole forming speed exceeds the billet forward speed, causing internal The hole is separated from the mandrel without contact, and the inner hole is not under pressure during the perforation deformation process, which is prone to inner hole cracks.
3. Sch40 astm a511 mt304 seamless stainless steel pipe changes the outer diameter and wall thickness by cold drawing and cold rolling. The work hardening after cold drawing and cold rolling needs to be eliminated by solid solution; When the steel pipe is slowly cooled, the carbides are not dissolved in the austenite grains and are precipitated at the grain boundaries. When the metal is deformed again, the precipitated hard carbides become the resistance to deformation, and cracks are prone to occur during cold drawing and cold rolling again.
4. The blank of sch40 astm a511 mt304 seamless stainless steel pipe is hot-rolled into a medium and thick plate, and after bending and longitudinal welding, it becomes a stainless steel welded pipe. The temperature during welding is too high, the layered welding is not used when the wall is thick, the wet towel is not covered in time after welding for cooling, the weld and the heat-affected zone are slowly cooled from the high temperature, and the carbides in the austenite are precipitated to the weld and heat-affected. In the grain boundary of the zone, the toughness of the weld and the heat-affected zone is greatly reduced, and thus weld cracks are generated.