Laser cutting is that the horizontal laser beam emitted by the laser changes into a vertical downward laser beam through the 45° total reflector, and then focuses through the lens, forming a tiny spot at the focal point. When the spot hits the material, the material is heated to the vaporization temperature quickly, and evaporates to form a hole. With the movement of the beam on the material such as sa 572 gr 50 low alloy steel plate, the auxiliary gas (carbon dioxide gas, oxygen, Nitrogen, etc.) blow away the melted slag, make the hole continuously form a very narrow width (such as about 0.1mm) cutting seam, and complete the cutting of materials.
S355J2 steel plate rolling process is controlled rolling process. In the rolling process, the ingot rolling temperature is 1000-1050℃; in the first stage, the low-speed and large reduction rolling process is adopted, the high-temperature stage is 950-1000℃, the sa 572 gr 50 low alloy steel plate rolling speed is 1.6-2.0m/s, the single reduction rate is 15-20%, and the cumulative reduction rate is 40-45%, so as to ensure sufficient deformation of ingot. In the first stage, the start rolling temperature is 910-930℃, and the finish rolling temperature is ≤ 870℃.
According to a report on the South African independent media website on March 1, the South African Iron and Steel and Engineering Industry Federation (Seifsa) announced the "Report on the State of the Metal and Engineering Industry for 2021-2022." The report pointed out that low capacity utilization, low imported product prices and rising electricity costs are the biggest obstacles facing South Africa's metal and engineering industries.