Chemical composition and function of stainless steel seamless pipes

Main elements and content of stainless steel seamless pipes:

The main elements of stainless steel seamless pipes (ss seamless pipe) include iron, chromium, nickel, manganese, molybdenum, etc., among which chromium is the most important component. The chromium content in stainless steel seamless pipes is generally above 10.5%, which plays a vital role in the corrosion resistance of stainless steel. The nickel content is generally above 8%, which has a great influence on the plasticity and corrosion resistance of stainless steel. The manganese content is generally around 2%, which can improve the strength and hardness of stainless steel. The molybdenum content is generally below 2%, which can improve the corrosion resistance of stainless steel. In addition, there are small amounts of silicon, phosphorus, sulfur and other elements.

Chemical composition and function of stainless steel seamless pipes:

1. Chromium (Cr)
The chromium content in stainless steel seamless pipes determines its corrosion resistance and oxidation resistance. It is a key component for rust prevention, and its content is generally between 16% and 18%. Chromium can react with oxygen to form a dense chromium oxide film, forming a self-healing passivation layer to prevent further corrosion. When the passivation layer on the surface of the stainless steel seamless pipe is damaged, chromium can regenerate the passivation layer with oxygen in the air to protect the stainless steel seamless pipe from further corrosion.

2. Nickel (Ni)
The nickel content in the stainless steel seamless pipe has a great influence on its plasticity and corrosion resistance. The addition of nickel makes stainless steel more ductile and tough, while improving its corrosion resistance. The content is generally between 10% and 14%. Nickel can improve the plasticity and toughness of stainless steel, making it easier to process and shape. At the same time, nickel can also improve the corrosion resistance of stainless steel, so that it can still maintain its performance in harsh environments.

3. Manganese (Mn)
The manganese content in the stainless steel seamless pipe can improve its strength and hardness, making it more wear-resistant. The content is usually 2%. At the same time, manganese can also improve the corrosion resistance of stainless steel, so that it can still maintain its performance in harsh environments.

4. Molybdenum (Mo)
The molybdenum content in the stainless steel seamless pipe can improve the corrosion resistance of the material in the chloride environment, so that it can still maintain its performance in corrosive environments such as strong acids and strong alkalis. In addition, molybdenum can also improve the strength and hardness of stainless steel, making it more wear-resistant, and its content is usually below 2%.

Other elements:

1. Carbon (C)
The carbon content in stainless steel seamless pipes is 0.04-0.10%, which has a certain effect on the strength and hardness of stainless steel pipes.

2. Phosphorus (P) and sulfur (S)
The phosphorus and sulfur content in stainless steel seamless pipes is usually very low. They are impurity elements and will be controlled during the production process to ensure the purity and performance of stainless steel pipes.

3. Silicon (Si)
The silicon content in stainless steel seamless pipes is usually 1-2%, which can improve the high temperature resistance and oxidation resistance of stainless steel pipes.

4. Nitrogen (N)
The nitrogen content in stainless steel seamless pipes is usually very low, but the performance of stainless steel pipes can be adjusted by controlling the nitrogen content, such as enhancing the strength and hardness of the material.

Advantages of stainless steel seamless pipes:

Stainless steel seamless pipes are pipes made of stainless steel. Their advantages are mainly reflected in the following aspects:

1. Corrosion resistance: Stainless steel seamless pipes have excellent corrosion resistance and can be used for a long time in a variety of corrosive environments. They are particularly suitable for chemical, marine and other industries.
2. High strength: Stainless steel itself has high strength and hardness, and the manufacturing process of seamless pipes also ensures the structural strength of the pipes.
3. No sand holes and cracks: Compared with welded steel pipes, seamless steel pipes have no welding seams, so there are no defects such as sand holes and cracks, and the overall performance is more stable.

4. High finish: The inner and outer walls of seamless pipes have high finish, low resistance, and smoother fluid flow, which helps to improve the conveying efficiency.
5. Plasticity and machinability: Stainless steel seamless pipes have good plasticity and machinability, and can easily carry out cutting, bending, welding and other processing processes.
6. Wide range of applications: Stainless steel seamless pipes can be used to transport various corrosive media, such as chemicals, acid and alkali solutions, seawater, etc.

7. Long-term cost-effectiveness: Although the initial cost of stainless steel seamless pipes is high, due to their durability and corrosion resistance, long-term use can save maintenance and replacement costs.
8. Environmental protection and energy saving: The structure of seamless pipes reduces material waste and contributes to environmental protection; at the same time, their good heat conduction performance also contributes to energy saving.
9. Beautiful appearance: Stainless steel materials have a silvery-white metallic luster, and the appearance of seamless pipes is neat and beautiful.
10. Easy to recycle: Stainless steel seamless pipes have good recyclability, which helps reduce environmental pollution.

Due to the above advantages, stainless steel seamless pipes have been widely used in occasions requiring high corrosion resistance, high strength and high-quality transportation.

Read more: Carbon steel tube vs Stainless steel tube or Seamless stainless steel pipe implementation standards