Types of stainless steel seamless pipes

Stainless steel seamless pipes (SS seamless pipe), as an important material in the industrial field, are favored for their excellent corrosion resistance, smooth surface and high strength. Stainless steel seamless pipes are commonly used in commercial and industrial applications, especially for fluid transportation. So, how many types of stainless steel seamless pipes are there? Next, we will analyze them in detail from multiple angles.

Types of stainless steel seamless pipes:

According to the metallographic structure and material of stainless steel, stainless steel seamless pipes can be divided into:

1. Austenitic stainless steel seamless pipes

Austenitic stainless steel is the most widely used type of stainless steel in the world. The corrosion resistance of austenitic stainless steel can be further improved by increasing the percentage of chromium, molybdenum and nitrogen in the base alloy. In addition, the steel becomes non-magnetic and can be easily bent, stretched or formed. It is worth noting that austenitic stainless steel cannot be hardened by heat treatment. Austenitic stainless steel is generally divided into 200 and 300 series. Grades 304/304L, 316/316L are the most commonly used stainless steels in the food industry, and they can maintain stable performance in a variety of harsh environments. This type of seamless pipe has good corrosion resistance and toughness and is widely used in industries such as food, pharmaceuticals and chemicals.

2. Ferritic Stainless Steel Seamless Pipe

Ferritic stainless steel has a high chromium content but a low carbon content (usually less than 0.1%). It is based on the body-centered cubic crystal structure of iron combined with a small amount of chromium. Although it can be cold worked, it cannot be heat treated. Despite its low resistance to welding, ferritic stainless steel has excellent resistance to stress corrosion cracking and is suitable for applications where high corrosion resistance and high temperature strength are required. It is magnetic similar to martensitic steel. However, its plasticity and toughness are relatively low and need to be selected according to specific needs. The most common ferritic grades are 430 and 409, which are mainly used in the automotive field.

3. Martensitic Stainless Steel Seamless Pipe

Martensitic stainless steel is a type of stainless steel with a low nickel content and a carbon content of up to 1%. This high carbon content enables it to be hardened and tempered, making it very hard and ideal for applications where strength, hardness and wear resistance are critical. Unlike typical austenitic stainless steel, martensitic stainless steel is magnetic. Common martensitic stainless steel grades include 410, 420 and 440C.

4. Duplex and Super Duplex Stainless Steel Seamless Pipes

Duplex and super duplex stainless steels are a combination of ferritic and austenitic stainless steels, combining the advantages of austenitic and ferritic stainless steels with high strength, good corrosion resistance and weldability. They can only be hardened by cold working. The most commonly used grades are 904L and 2205, which contain higher levels of chromium, nickel and other alloying elements (such as nitrogen or copper) to enhance their structure and performance. Duplex and super duplex stainless steels are often used in applications requiring high strength due to their excellent mechanical strength, high corrosion resistance and good weldability. These materials are favored for their ability to withstand harsh environments and maintain their structural integrity. It should be noted that duplex and super duplex stainless steel pipes should be used in accordance with industry standards and guidelines to ensure optimal performance and service life. This type of seamless pipe has a wide range of applications in fields such as oil, gas and offshore engineering.

Classification by manufacturing process:

According to the manufacturing method, there are:

- Hot rolling
The seamless pipe produced by hot rolling process has a rough surface but high dimensional accuracy, which is suitable for pipeline systems with general requirements. During the hot rolling process, the steel pipe is deformed at high temperature, which can significantly improve the processing performance and mechanical properties of the material.

- Cold processing (cold rolling and cold drawing)
The cold-rolled seamless pipe has a smooth surface and high dimensional accuracy, which is suitable for occasions with high requirements for pipeline systems. The cold rolling process can refine the grains and improve the strength and hardness of the material, but the production cost is high.

Classification by use:

1. Seamless pipes for oil and gas: This type of seamless pipe needs to withstand high pressure, high temperature and corrosive media, so it has extremely high requirements for its material and manufacturing process. Common materials include stainless steel, alloy steel, etc.

2. Seamless pipes for chemical industry: The chemical industry has extremely high requirements for the corrosion resistance and high temperature resistance of seamless pipes. Stainless steel seamless pipes are widely used in chemical equipment, pipelines and storage tanks due to their good corrosion resistance.

3. Seamless pipes for medical devices: Seamless pipes for medical devices need to meet strict hygiene standards and non-toxic requirements. Stainless steel seamless pipes are widely used because of their easy cleaning, disinfection and corrosion resistance.

In summary, there are many types of stainless steel seamless pipes, each with its own unique characteristics and application scenarios. When choosing stainless steel seamless pipes, comprehensive considerations should be made based on specific needs to ensure that the material can meet the use requirements and have good economic benefits.

Read more: Stainless Steel Seamless Pipe Manufacturing Process or 304 vs. 316 Stainless Steel