What chemical elements affect the quality of steel pipes

At present, my country is actively developing the steel structure industry. First, actively expand the variety of large-diameter spiral steel pipes for building steel structures and improve product performance. Including high-quality welded structural steel, high-strength high-quality thick plates, hot-formed pipes, high-quality weldable cast steel, etc.; expand the variety and specifications of cold-bent steel and hot-rolled H-shaped steel, including large-section cold-bent pipes, large-section H-shaped steel and light H-shaped steel, etc.; reasonably promote the use of weathering steel, fire-resistant steel, Z-direction steel and flux-cored welding rods, etc. Secondly, vigorously promote the development of building steel structures and further improve their application technology level. My country's steel structure industry is developing rapidly. Steel structure buildings are a new type of energy-saving and environmentally friendly building system. Steel structure buildings are a kind of building structure with lightweight, high strength, good seismic performance, energy-saving and environmental protection, and can be recycled. It meets the requirements of developing energy-saving buildings and sustainable and healthy economic development. Steel pipes also include special systems for transporting liquefied petroleum gas and liquefied natural gas. The service life of steel pipes in marine engineering is at least 40 years. In addition to conventional systems, marine engineering also has special drilling and production equipment systems, and process systems for crude oil, liquefied petroleum gas, and liquefied natural gas.

Steel pipes can be divided into round pipes and special-shaped pipes according to the shape of the cross-sectional area. Since the area of a circle is larger under the condition of equal circumference, a round pipe can transport more fluid. In addition, the circular cross-section is subjected to more uniform force when subjected to internal or external radial pressure. Therefore, most steel pipes are round pipes.

What chemical elements affect the quality of steel pipes?

(1) Nickel (Ni): Nickel can increase the strength of steel and keep the steel in good plasticity and toughness. The influence of several main elements in steel on the properties of steel.

(2) Chromium (Cr): Chromium can significantly increase the strength, hardness, and wear resistance of steel, but at the same time it will reduce plasticity and toughness.

(3) Titanium (Ti): Titanium is a deoxidizer in steel. Reduces effective sensitivity and cold brittleness. Adding a corresponding amount of titanium to steel can resist intergranular corrosion.

(4) Molybdenum (Mo): Adding molybdenum to steel can improve the mechanical properties of steel.

(5) Carbon (C): As the carbon content increases, the yield point and tensile strength increase, but the plasticity and impact properties decrease. Too high a carbon content can easily cause intergranular corrosion failure. The boundary between steel and iron is controlled by the C content.

(6) Sulfur (S): Sulfur is a harmful element in steel. It makes steel hot and brittle, reduces the ductility and toughness of steel, easily causes cracks during forging, and also reduces the corrosion resistance of steel. Therefore, the sulfur content must be kept as low as possible.

(7) Silicon (Si): Si is a deoxidizer and desulfurizer. It has high strength and hardness and can improve the hot working properties of steel.

(8) Phosphorus (P): Phosphorus is a harmful element in steel. It increases the cold brittleness of steel, deteriorates welding properties, reduces plasticity, and deteriorates cold bending properties. Under normal circumstances, the lower the phosphorus content in steel, the better.

(9) Nitrogen (N): Nitrogen can improve the strength, low-temperature toughness, and weldability of steel. Increases effective sensitivity. An appropriate amount of nitrogen can improve the pitting corrosion resistance and strength of stainless steel.