How does the crack on the surface of hot rolled steel coil s275jr s355jr cause

A medium tensile, low carbon manganese steel S355JR is readily weldable and possess good impact resistance. This material is commonly supplied in the untreated or normalized condition. Structural unalloyed steel hot rolled steel coil s275jr s355jr has a wide range of applications in construction, metallurgy, heavy and transport engineering, machine tool, power engineering and bridge building industries. Various profiles and metal structures, parts and elements of ground and underground equipment are made from steel S355JR.

Phosphorus element (P element) is brought into steel by ore. Generally speaking, phosphorus is also harmful element. Although phosphorus can increase the strength and hardness of hot rolled steel coil s275jr s355jr etc. steel, it also causes the decrease of plasticity and impact toughness. Especially at low temperature, it makes steel significantly brittle, which is called "cold brittleness". The higher the phosphorus content is, the greater the cold brittleness is. Therefore, the phosphorus content in hot rolled steel coil s275jr s355jr etc. steel is strictly controlled.

If it is 6 mm hot rolled steel coil s275jr s355jr low carbon steel plate, when laser cutting, about 19 yuan per meter. 10 mm low carbon steel plate to do laser cutting, the price of one meter is about 15 yuan. If the hot rolled steel coil s275jr s355jr steel plate is 12 mm, the price of one meter is about 15 yuan.

According to the data of the National Bureau of statistics, from January to February, the output of pig iron, crude steel and steel (excluding repetitive materials) were 132.34 million tons, 154.7 million tons and 167.13 million tons, respectively, up 3.1%, 3.1% and 3.4% year on year; the daily output of hot rolled steel coil s275jr s355jr, crude steel was 2.5783 million tons, down 5.15% year on year.