Common elements that affect the performance of seamless steel pipes

The quality and performance of seamless pipes are determined according to needs. According to different needs, different element contents and types must be matched with them.

(1) Carbon: The higher the carbon content, the higher the hardness of steel, but the worse its plasticity and toughness.
(2) Sulfur: It is a harmful contaminant in steel. When steel with high sulfur content is subjected to pressure processing at high temperature, it is easy to crack, which is usually called hot brittleness.

(3) Phosphorus: It can significantly reduce the plasticity and toughness of steel, especially at low temperature. This phenomenon is called cold brittleness. In high-quality steel, sulfur and phosphorus should be strictly controlled. But on the other hand, the high content of sulfur and phosphorus in low carbon steel can make it easy to cut, which is beneficial to improve the machinability of steel.

(4) Manganese: It can improve the strength of steel, weaken and eliminate the adverse effects of sulfur, and improve the hardenability of steel. High-alloy steel (high-manganese steel) with high manganese content has good wear resistance and other physical properties.
(5) Silicon: It can improve the hardness of steel, but the plasticity and toughness decrease. The steel used for electrician contains a certain amount of silicon, which can improve the soft magnetic properties.

(6) Tungsten: It can improve the red hardness and thermal strength of steel, and can improve the wear resistance of steel.

(7) Chromium: It can improve the hardenability and wear resistance of steel, and can improve the corrosion resistance and oxidation resistance of steel.

(8) Vanadium: It can refine the grain structure of steel and improve the strength, toughness and wear resistance of steel. When it melts into austenite at high temperature, it can increase the hardenability of steel; on the contrary, when it exists in carbide form, it will reduce its hardenability.

(9) Molybdenum: It can obviously improve the hardenability and thermal strength of steel, prevent temper brittleness, and improve remanence and coercive force.

(10) Titanium: It can refine the grain structure of steel, thereby improving the strength and toughness of steel. In stainless steel seamless steel pipe, titanium can eliminate or reduce the intergranular corrosion phenomenon of steel.
(11) Nickel: It can improve the strength and toughness of steel and improve hardenability. When the content is high, some physical properties of steel and alloys can be significantly changed, and the corrosion resistance of steel can be improved.

(12) Boron: When the steel contains a small amount of (0.001-0.005%) boron, the hardenability of the steel can be doubled.

(13) Aluminum: It can refine the grain structure of steel and inhibit the aging of low carbon steel. Improve the toughness of steel at low temperature, but also improve the oxidation resistance of steel, improve the wear resistance and fatigue strength of steel.
(14) Copper: Its prominent role is to improve the atmospheric corrosion resistance of ordinary low-alloy steels, especially when used in conjunction with phosphorus.