Tungsten enhances the red hardness, hot strength, and wear resistance of spiral steel pipes.
Silicon improves the hardness of spiral steel pipes but reduces their plasticity and toughness. A certain amount of silicon in spiral steel pipes used in electrical engineering can improve soft magnetic properties.
Chromium increases the hardenability and wear resistance of spiral steel pipes, as well as improves their corrosion resistance and oxidation resistance. To enhance the corrosion resistance of anti-corrosion spiral steel pipes (black pipes), galvanization is performed.
Sulfur is a harmful impurity in spiral steel pipes. Higher sulfur content makes the pipes prone to embrittlement during hot pressure processing, commonly known as hot shortness.
Carbon content directly correlates with the hardness of steel; the higher the carbon content, the harder the steel, but with decreased plasticity and toughness.
Manganese enhances the strength of spiral steel pipes, mitigates the adverse effects of sulfur, and improves their hardenability. High-alloy spiral steel pipes with high manganese content (high-manganese spiral steel pipes) exhibit excellent wear resistance and other physical properties.
Phosphorus significantly reduces the plasticity and toughness of spiral steel pipes, especially at low temperatures. This phenomenon is known as cold shortness. In high-quality spiral steel pipes, sulfur and phosphorus content must be strictly controlled. However, from another perspective, higher sulfur and phosphorus content in low-carbon spiral steel pipes can facilitate easy chipping, which is beneficial for improving the machinability of spiral steel pipes.
