The grade and application of nickel-iron in stainless steel welded pipe

In 1804, after the initial extraction of metallic nickel from the ore, due to technical limitations and lack of resources at that time, nickel did not develop significantly in about 100 years. Until the eve of World War I, the world's nickel output was only a few thousand tons. After one time, especially after the Second World War, nickel production increased dramatically. In 1865, Garnier took magnesium magnesium nickel ore and added gypsum and coal.

In 1865, Garnier reduced the smelting of silicon-magnesium-nickel ore, gypsum and coal, and obtained nickel and bismuth after reduction, thereby enriching a small amount of nickel in the ore. After burning off the sulfur, the obtained nickel oxide is reduced to nickel in a solid state through carbon.

Nickel is completely soluble in γ-iron, and the solubility in α-iron is 10%. Nickel content up to 5% can improve the tensile strength and hardness of low-carbon structural steel. Carbon steel containing 3% nickel to improve its tensile strength impact toughness yield point and deformability. NiCrMo structural steel containing 1% -4% nickel is suitable for automotive locomotive and machinery manufacturing, because the ratio of tensile strength to quality of the steel is appropriate. In addition to these elements, wear-resistant component steel also contains carbon. The important nickel-containing steel plates and larger users are stainless steel and heat-resistant special steel. For example, a series of heat-resistant stainless steels such as Cr18Ni9Ti Cr17Ni11Mo2 have good hot workability and are widely used in mechanical medical defense light industry.

Nickel has a slight graphitization effect in cast iron, which can stabilize pearlite and reduce the ferrite content. Therefore, the nickel in the cast iron helps to form a uniform structure and good performance. The addition of a small amount of nickel (Ni 0.1% -1.0%) leads to the formation of fine pearlite, and martensite and austenite are formed when the nickel content is high. High-quality and stable pearlite gives cast iron good processing properties and hardness. Therefore, nickel-added cast iron can be used to manufacture castings in the automotive industry.