16mo3 steel what effect does the sulfur (S) element of the plate have on weldability?

16Mo3 steel is a European boiler steel plate, used to make boilers or pressure vessels.

Sulfur is often present in the form of iron sulfide in 16Mo3 steel, and it is distributed in the grain boundary in a network. Therefore, the toughness of steel is significantly reduced. The eutectic temperature of iron plus iron sulfide is relatively low (985°C). Therefore, during hot processing, the starting temperature of processing is generally 1150~1200℃, and the eutectic of iron and iron sulfide has melted, which leads to cracking during processing. This phenomenon is the so-called "hot brittleness of sulfur". This property of sulfur causes hot cracks in 16Mo3 steel during welding. Therefore, the sulfur content in steel is generally strictly controlled.

16Mo3 welding is different from other materials, it must be preheated first, and the welding seam should be kept for about 30 minutes after the welding is completed. Manganese is also an important alloying element in steel and an important hardenability element. It has a great influence on the toughness of weld metal.