What is the role of welding preheating for NM400 material meaning

Z-direction steel refers to thick steel with good tensile resistance in thickness direction. In the application of steel plate, the reason for additional performance requirements on the thickness direction of steel is due to the existence of defects in the thickness direction of steel in the process of casting and rolling. This defect makes the steel prone to lamellar tearing during welding, which reduces or even loses the design bearing capacity of application. The Z-direction performance is required for NM400 material meaning and so on steel plate with the tensile force along the plate thickness direction greater than or equal to 40mm.

The microstructure of NM400 wear plate, NM400 material meaning depends on the chemical composition. In addition to carbon, ordinary wear-resistant plate generally contains vanadium, tungsten, chromium, aluminum and other alloy elements. Carbon is the basic element of NM400 wear plate, NM400 material meaning. Increasing the carbon content in the steel to the level of "balanced carbon" can improve the wear resistance of the steel. When the carbon content is insufficient, the amount of carbides will decrease correspondingly, and the wear resistance and cutting performance of the steel will decrease.

The advantages of NM400 material meaning, seamless steel pipe are high pressure resistance, good toughness, long pipe section and few joints. It is widely used and the rolling technology of domestic steel mills is also very mature. Compared with round steel, the weight of seamless steel pipe is lighter under the same strength. Seamless steel pipe manufacturing ring parts, can improve the utilization of materials, simplify the manufacturing process, save materials and processing time. Compared with the welded pipe, there is no weld on the outer surface of seamless steel pipe, and it has good compression resistance.

On October 30, the Ministry of Ecology and Environment issued the "Action Plan for Comprehensive Control of Air Pollution in the Yangtze River Delta Region in the Fall and Winter of 2020-2021". The "Plan" stated that the steel production capacity of Tianjin will be controlled at 15 million tons by the end of December 2020. Around this time, Hebei’s steel production capacity will be controlled within 200 million tons, and the elimination of 4.3-meter coke ovens with longer furnace age and poor furnace conditions will be accelerated, and independent coking companies will gradually withdraw.