The S355J2 steel plate production process includes steelmaking, heating, steel rolling and normalizing processes; the steel rolling process adopts a type controlled rolling process. In the steel rolling process, the steel ingot is rolled at a temperature of 1000～1050; the low-speed and high-reduction rolling process is adopted in the first stage, the high-temperature stage is 950-1000, the rolling speed is 1.6-2.0m/s, and the single-pass reduction rate is 15-20%. The reduction rate is 40-45% to ensure sufficient deformation of the steel ingot. In the first stage, the starting rolling temperature is 910～930, and the final rolling temperature is ≤870.
1. Describe the steelmaking process, using the smelting process combining electric furnace + LF furnace. During the VD vacuum treatment, the vacuum degree is ≤66Pa, the vacuum holding time is 20-25min, and the steel ingot is made after being broken.
2. In the heating process, the steel ingot is heated in the soaking furnace, the highest heating temperature is 1270, and the temperature of the soaking section is 1250~1260 to ensure uniform heating inside and outside the ingot.
3. Normalizing process, the steel plate is normalized in the bottom of the car, the steel plate normalizing temperature is 880～910, and the holding time is 1.8～2.2min/mm, then the required S355J2+N-Z35 steel plate is obtained.
The
meaning of S355J2+N-Z35 steel: J2 requires a negative 20 degree impact, and N means the equivalent of normalizing rolling, not necessarily normalizing, but a method of naming steel grades in the standard. Z35 is the Z-direction performance of the steel plate.
S355J2 steel carbon content (melting analysis) is generally not more than 0.20%, the total content of alloying elements is generally not more than 2.5%, and the yield strength is not less than 295MPa. S355J2 steel is a low alloy steel with good impact toughness and welding performance. S355J2 steel plates are used in construction, bridges, ships, vehicles, pressure vessels and other junctions.
