Seamless steel pipe and welded pipe are two common types of steel pipes, which have different characteristics and scopes of application in use. This article will introduce the difference between seamless steel pipe and welded pipe in detail in terms of material, manufacturing process, performance, and application.

Material

Seamless steel pipes are processed from a single piece of steel, usually made of carbon steel, alloy steel, stainless steel, etc. Welded pipes are made of steel plates or strips through crimping, forming, welding, and other processes. The materials also include carbon steel, alloy steel, stainless steel, etc.

Manufacturing Process

The manufacturing process of seamless steel pipe is processed through multiple processes such as billet heating, piercing, rolling, etc., and no welding is required in the whole process. The welded pipe is made of steel plate or strip through crimping, forming welding, and other processes. The welding methods include high-frequency welding, arc welding, gas-shielded welding, etc.

Performance

1. Strength and hardness

The strength and hardness of the seamless steel pipe are relatively high because it is processed from a single piece of steel, and there is no weak spot at the weld. The strength and hardness of the welded pipe are relatively low because defects such as cracks and pores are prone to appear in the weld, which affects the overall performance of the steel pipe.

2. Toughness and ductility

The toughness and ductility of seamless steel pipes are relatively poor because they are processed from a single piece of steel without the plasticity of welds. The toughness and ductility of the welded pipe are relatively good because the weld has a certain degree of plasticity and can withstand certain deformation and extrusion.

3. Corrosion resistance

The corrosion resistance of seamless steel pipes and welded pipes is related to the material, and steel pipes of different materials have different corrosion resistance properties. Generally speaking, stainless steel seamless steel pipes and welded pipes have the best corrosion resistance, followed by carbon steel and alloy steel.

Application

Seamless steel pipes and welded pipes have different scopes of application.

1. Seamless steel pipe

Seamless steel pipes are suitable for occasions with high requirements such as high pressure, high temperature, low temperature, corrosion, wear resistance, etc., such as petroleum, chemical industry, electric power, aviation, aerospace, machinery, and other fields. The advantages of seamless steel pipes are high strength, pressure resistance, corrosion resistance, wear resistance, and no leakage. The disadvantages are high cost and difficult processing.

2. Welded pipe

Welded pipes are suitable for general low-pressure, low-temperature, non-corrosive, non-wear-resistant occasions, such as construction, bridges, highways, water conservancy, mining and other fields. The advantages of welded pipes are low cost, simple processing, and high production efficiency. The disadvantages are low strength, prone to welding defects, and easy to be corroded.

To sum up, seamless steel pipes and welded pipes have different characteristics and scope of application in terms of material, manufacturing process, performance and application. When choosing a steel pipe, it should be selected according to the specific use occasion and requirements to achieve the best use effect.

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