Every customer who has visit us and witness the steel materials before delievry will be impressed by our quality control departemnt. Even not come to inspect the steel materials before delievry, our quality control departemnt will also send inspection report to the customer. For each order, no matter its quantity and value, our quality control departemnt will make strict inspection before delivery, the inspection contents include apperance, tolerance, dimension, mark, special requirements of customers, etc. To guarantee our steel materials sent to the customer is qualified.
Low-alloy steel plates have low carbon content, and because ferrosilicon is not used for deoxidation, the silicon content in steel is often <0.07%. The outer layer of rimmed steel is crystallized in a rimmed state, so the surface layer is pure and dense, the surface quality is good, and the Zhengzhou low alloy steel plate SA572 Grade 55 and A572 Grade 60 structural alloy has good processing performance. Rimmed steel does not have large concentrated shrinkage cavities, uses less deoxidizer, and the cost of steel is low.
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 SA572 Grade 55 and A572 Grade 60 structural alloy are higher than that of annealed SA572 Grade 55 and A572 Grade 60 structural alloy, but the elimination of internal stress is not as good as annealing. The normalizing operation of SA572 Grade 55 and A572 Grade 60 structural alloy is simple, the cost is low, the productivity is high, and it is widely used in actual production.
In 2016. Our company offer 1200 tons API 5L GR.B hot rolled coil to Bangladesh——100 tons for 3.9*625mm, and 1100 tons for 7*683mm. It is one tender project, we get the tender at the end of 2015, and arrange the production in 2016. They required the tolerance of thickness is +0.1/-0.2mm, and width tolerance is +/-0.5mm, which is a very high requirement for coil tolerance, but our mill handling this very well. and our Q/C department witness all of the process.