Effect of laser welding technology on weld microstructure of JIS SM400C plates

The difference between JIS SM400C plates, hot rolled sheet and cold rolled sheet: hot rolled sheet has low hardness, easy processing and good ductility. The cold-rolled sheet has high hardness and relatively difficult processing, but it is not easy to deform and has high strength. The cold rolled sheet is mostly used in automobile manufacturing and electrical products. Therefore, the two have their own characteristics. According to these characteristics, it is more appropriate to choose the right rolled plate to maximize its effect and benefit.

South Korean JIS SM400C plates steel industry said that the slowdown in economic growth superimposed on the impact of the epidemic, steel demand weakened, exports were sluggish, enterprises are facing huge operating pressure. Due to the delay in the resumption of work of Chinese JIS SM400C plates steel enterprises, the steel inventory is growing rapidly. According to statistics, China's steel circulation inventory reached 23.75 million tons in February, the highest since 2006, with an estimated total inventory of 33.45 million tons.

Generally speaking, rolled plates are easier to handle in a high temperature environment, and the heat treatment of JIS SM400C plates, rolled plates is also very common. Hot rolling can not only greatly reduce energy consumption and save costs, but also improve the processing performance of metals and alloys, that is, the coarse grains in the as-cast state are broken, the cracks are healed significantly, and the processing performance of the alloy is improved.

For Q345B steel plate, Q stands for the yield of Q345B material. The 345 at the back refers to the yield value of Q345B material, which is about 345MPa. The yield value will decrease with the increase of Q345B steel plate thickness. Q345B steel plate has good comprehensive performance, low temperature performance, cold stamping performance, welding performance and machinability. It JIS SM400C plates is widely used in bridges, vehicles, ships, buildings, pressure vessels, etc.