According to the quality and performance of steel pipes (seamless pipes or welded pipes), we have summarized the properties of different metal elements contained in them.

1. Carbon: The higher the carbon content, the higher the hardness of the steel pipe, but the worse the plasticity and toughness.

2. Sulfur: It is a harmful impurity in steel pipes. If the sulfur content in the steel is high, it is easy to become brittle at high temperature, which is usually called hot brittleness.

3. Phosphorus: It can significantly reduce the plasticity and toughness of steel, especially at low temperatures. 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 cutting performance of steel.

4. Manganese: It can increase the strength of steel, weaken and eliminate the adverse effects of sulfur, and improve the hardenability of steel. High alloy steel with manganese content (high manganese steel) has good physical properties such as wear resistance.

5. Silicon: It can increase the hardness of steel, but the plasticity and toughness will decrease. But silicon can improve soft magnetic properties.

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

7. Chromium: It can improve the hardenability, wear resistance, 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 the form of carbide, its hardenability will be reduced.

9. Molybdenum-Mo; can significantly improve the hardenability and heat strength of steel, prevent temper brittleness, and improve remanence

10. Titanium-Ti; can refine the grain structure of steel, thereby improving the strength and toughness of steel. In stainless steel, titanium can eliminate or reduce the intergranular corrosion of steel.

11. Nickel-Ni; can improve the strength and toughness of steel, improve hardenability, when the content is high, it can significantly change some physical properties of steel and alloys, and improve the corrosion resistance of steel.

12. Boron-B; when the steel contains a small amount (0001-0.005%) of boron, the hardenability of the steel can be doubled.

13. Aluminum-Al: It can refine the grain structure of steel, inhibit the aging of low-carbon steel, improve the toughness of steel at low temperature, improve the oxidation resistance of steel, improve the wear resistance and fatigue strength of steel, etc. .

14. Copper-Cu; its outstanding function is to improve the atmospheric corrosion resistance of ordinary low alloy steel, especially when it is used in conjunction with phosphorus.