The reason for wrong layer problem of weather resistant Q355NH steel

SM490B plate is a kind of structural steel produced according to Japanese Standard JIS G3106. Min. tensile strength of SM490B plate is 490MPa. SM490B plate is mainly used in buildings, bridges, ships, rail vehicles, oil tanks, containers and other buildings requiring high-level weldability. The delivery state is hot rolling for SM490B plate, weather resistant Q355NH steel with thickness less than 80mm; and the delivery state is normalizing for SM490B steel plate with thickness more than 80mm.

Diffusion annealing of weather resistant Q355NH steel, wear-resistant plate is to reduce the non-uniformity of chemical composition and structure of metal ingot, casting or forging billet, heating it to high temperature and holding for a long time to make the elements in the steel plate fully diffuse. Due to the long heating cycle and high temperature of diffusion annealing, although the composition of the steel is uniform, the structure of the steel plate is seriously overheated, and the grains grow violently, and the toughness and plasticity are poor. Diffusion annealing is widely used in ingots, casting and forging billets with high quality requirements due to its high energy consumption and serious burning loss.

Ultrasonic flaw detection emits ultrasonic waves to the weather resistant Q355NH steel steel plate under inspection. If there are defects in the steel plate, the ultrasonic waves will reflect, refract or deform waveforms due to the defects. By recording these changes, the type and shape of the defects are analyzed. Due to its high energy and good penetration performance, and the smoothness of the weather resistant Q355NH steel steel plate itself, ultrasound is often used to detect defects such as inclusions, shrinkage holes, bubbles, and cracks in the steel plate.

The company adopts one-to-one fast service and has formed a professional after-sales service team to deal with various problems reflected by customers as soon as possible. At the same time, a traceable product traceability system has been established. It has always been placed at an important core position to resolve customer worries. Our steel weather resistant Q355NH steel products are always committed to “quality issues, life-long replacement”, which is the embodiment of our comprehensive service.