Normalizing is to heat the steel parts to 30~80℃above the critical temperature for a period of time. Then the parts are taken out of the furnace and cooled in air. Since the cooling rate of normalizing is faster than that of annealing, the strength and hardness of normalized A709 grade 50W structural steel sheet are higher than that of annealed A709 grade 50W structural steel sheet, but the elimination of internal stress is not as good as annealing. The normalizing operation of A709 grade 50W structural steel sheet is simple, the cost is low, the productivity is high, and it is widely used in actual production.
Thin steel 5mm to 10mm A709 grade 50W structural steel sheet stock list 5*2550*9200, 5.5*2500*10000, 5*2670*8500, 7*2260*8600, 6*2510*10400, 5*1860*12000, 8*2000*10000, 7*2000*8000, 8*2350*8600, 10*2500*8500, 8*2540*8200, 9*2500*9500, 10*2510*10600, 8*2400*6000, 10*2550*8500, 10*2800*6300, 10*1600*12000, 10*2000*6500, 10*2650*8300, 10*2800*6150, 10*2000*8600, 10*2150*5500.
Since March 20, 2020, the export tax rebate rate of some steel products in China has been increased. According to statistics, the export volume of A709 grade 50W structural steel sheet and so on steel products within the adjustment scope in 2019 is 18.888 million tons, accounting for 29.4% of China's total steel exports; the export volume is 14.05 billion US dollars, accounting for 26.1% of the total steel exports. The adjustment will be conducive to the export of some steel products in China and reduce the purchase cost of foreign customers.
Chromium element (Cr element) can improve the strength and hardness of A709 grade 50W structural steel sheet, carbon steel in rolling state, reduce elongation and area reduction. When the chromium content is more than 15%, the strength and hardness will decrease, while the elongation and reduction of area will increase correspondingly. It is easy to obtain high surface processing quality for steel parts containing chromium after grinding. The main function of chromium element (Cr element) in quenched and tempered steel structure is to improve hardenability, so that the steel has better comprehensive mechanical properties after quenching and tempering.
