Recently, the hot-rolled weathering steel Q345NQR2 for railway rolling stock has been successfully trial-produced, and its surface quality and mechanical properties have been recognized by customers.
From low strength ordinary carbon steel and low strength weathering steel to high strength weathering steel, with the development of steel technology and the requirement of high speed, heavy load, and low cost of railway vehicles, the rolling stock body material realizes the turn from the low end to the high end.
To get a slice of the pie in the rolling stock industry, in April this year, based on the successful development of Q310NQL2 weathering steel and extensive market research, the technicians of the Hongxing steel sheet plant and the Institute of Carbon Steel Sheet and strip research of the iron and Steel Research Institute tried their best to attack the hot-rolled weathering steel Q345NQR2.
“Different types of products have different paths,” said GE Liping, head of product development at the Institute of Carbon Steel and strip research. Hot-rolled weathering steel Q345NQR2 is low-alloy steel made by adding a certain amount of copper, phosphorus, chromium, nickel, and other elements to ordinary steel.
The atmospheric corrosion resistance, life is about 4 times of ordinary steel, mainly Xuxu made of railway vehicle doors.
The CSP production line has compact flow and high speed, and the maximum time from molten steel to the hot rolled coil is less than 4 hours. After adding collars such as copper, chromium, and nickel, it is easy to cause mold powder denaturation, affect heat transfer, even lead to slab crack and bonding breakout, and the oxide scale on the slab has a high viscosity and is not easy to remove. Cause surface quality defects. It is a piece of cake to produce weathering steel on a conventional hot continuous rolling line, but it is very difficult to produce on CSP.
“But JISCO has only one hot-rolled production line, CSP,” Liping said. “We can only gnaw at this ‘hard bone’ based on the existing technology, equipment, and equipment.”
Master the processing characteristics, make a rolling plan, clear the Operation Essentials, adjust the alloy ratio, optimize the production process, and strengthen production and division… Finally, hot-rolled weathering steel Q345NQR2 has been successfully trial-produced recently and has won the favor of customers and become the highest value-added carbon steel hot-rolled product.
“The upgrading of rolling stock is unstoppable, and the demand for weathering steel will increase,” he said. Next, the plant will further optimize the process and work on improving the quality of hot-rolled weathering steel products, he said, at the same time, great efforts have been made to develop low-cost and economic weathering steel, which will help the high-quality development of JISCO.
