Preventing H-beam cracking methods
H-beams are deep-drawn parts with a high degree of deformation and curvature. It is harmless to use PTFE film as a lubricant in production. Since PTFE film has the property of tear strength, it is also related to the lubricant. Such lubrication can isolate the deformation of the stainless steel and mold surface, lubrication effect is always good, but also help to extend the service life of the mold operation and product qualification rate.
H-beam price stretched to prevent cracking, and some other precise preventive measures. There is no harm in operating some of the white cast iron abrasives used for crimping rings. Because of the good oil storage function of white cast iron, it becomes a greasy oil film. h-beam is also bound to use a conical crimping ring. Next, the edge processing of the workpiece is de-greased and the gap is removed. So stopping the crack is just as useful.
Thermal cracking is cracking that occurs at high temperatures, also known as high-temperature cracking or crystallization cracking. It usually occurs in welds and can sometimes occur in the heat affected zone. It occurs due to the presence of segregation in the weld pool during the crystallization process, and segregation is formed by the presence of low melting point eutectic and impurities in the form of liquid interlayers during the crystallization process. The strength is also low after solidification. When the welding stress is large enough, the liquid interlayer or just solidified solid metal will be pulled apart to form cracks.
H-beam steel manufacturers take preventive measures according to the cause, limit the content of easy to segregate elements and harmful impurities in the parent material and welding materials, especially to control the content of sulfur and phosphorus, reduce carbon content. The content of sulfur and phosphorus in welding steel should generally not be greater than 0.045% and 0.055%. In addition, the farther the carbon content of the steel, the worse the weldability. Generally speaking, when the carbon content in the weld is controlled below 0.10%, the hot crack sensitivity can be greatly reduced.
Adjust the chemical composition of the weld metal, improve the weld organization, refine the weld grain to improve its plasticity, reduce or disperse the degree of segregation, and control the harmful effects of low melting point co-products. Alkaline electrodes or fluxes are used to reduce the impurity content in the weld and improve the degree of segregation in the crystallization process.
