steel S690QL1 surface quality problems

A203GrD steel plate belongs to ultra-low temperature container plate. ASTM A203 is a low-nickel alloy steel, including five grades A, B, D, E, and F. Among them, Grades D, E, and F have a nominal nickel content of 3.5%, commonly known as 3.5Ni steel. A203D/E/F steel has good impact toughness and mechanical properties in a low temperature environment, and is usually used in a low temperature environment of -70～-101℃ (the tempered state can reach -107℃).

Our company's steel S690QL1 power boilers, heating furnaces of double bars, double high lines and medium and thick plates all adopt heat storage technology, which can fully use blast furnace gas; the ladle baking, Maerz active lime kiln and medium and thick plate heat treatment furnace all burn converter gas, which can improve the steel S690QL1 utilization rate of secondary energy and realize negative energy steelmaking in steelmaking process.

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 steel S690QL1 are higher than that of annealed steel S690QL1, but the elimination of internal stress is not as good as annealing. The normalizing operation of steel S690QL1 is simple, the cost is low, the productivity is high, and it is widely used in actual production.

EN10025-6 S460QL structural steel plates are European standard low alloy high strength steel materials. steel S690QL1, S460QL steel plates are mainly used for building and engineering structures, such as plant structure, body steel frame components of bulldozers, loaders etc. all kinds of construction machinery, bridges, ships and so on.

Through the operation and management, brand advantage and improve pre-sales, sale of after-sales service, the efforts of the company into the industry leading enterprises.Relying on perfect quality management system, it has built up competition predominance and provided high quality, favorable price and perfect after service for customers.

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