Welded steel pipe, also known as welded pipe, is a steel pipe made by welding steel plates or strip steel after being curled and formed. The types of welded steel pipes can be classified from multiple dimensions, and the specific classification methods and corresponding types are as follows:

1. Classified by weld seam form

Straight seam welded pipe: a welded steel pipe with a weld seam parallel to the longitudinal direction of the steel pipe. Smaller diameter welded pipes are usually welded using straight seam welding.

Spiral welded pipe: a welded steel pipe with a spiral distribution of welds. Spiral welding is commonly used for large-diameter welded pipes.

2. Classified by production method

Electric arc welded pipe: Steel pipe made by electric arc welding process.

Resistance welded pipe: Steel pipes made by heating the edges of steel plates or strips to a plastic state using resistance heat and then pressing them together, including high-frequency welded pipes and low-frequency welded pipes. Among them, there are two types of high-frequency welded steel pipes: induction welding and contact resistance welding.

Gas welded pipe: a steel pipe welded using a gas flame as a heat source.

Furnace welded pipe: a steel pipe welded in a furnace.

3. Classified by the shape of the steel pipe end

Circular welded pipe: a welded steel pipe with a circular end.

Irregular welded pipe: welded steel pipe with square, rectangular or other shapes at the end of the steel pipe.

4. Classified by material and purpose

General welded pipe: used for conveying low-pressure fluids, commonly made of Q195A, Q215A, Q235A steel.

Galvanized welded pipe: In order to improve the corrosion resistance of steel pipes, general steel pipes are subjected to galvanizing treatment, which is divided into two types: hot-dip galvanizing and electroplating galvanizing.

Oxygen blown welded pipe: used as a pipe for oxygen blowing in steelmaking, generally using small-diameter welded steel pipes.

Wire conduit: Used for concrete and various structural power distribution projects, commonly with nominal diameters ranging from 13-76mm.

Metric welded pipe: a welded steel pipe with specifications in seamless pipe form, expressed in millimeters of outer diameter and wall thickness.

Roller tube: an electric welded steel pipe used for the rollers of belt conveyors.

Deep well pump pipe: Steel pipe used for deep well pump systems.

Automotive pipe: Steel pipe used for automobile manufacturing and maintenance.

Transformer tube: Steel tube used for manufacturing transformer heat dissipation tubes and other heat exchangers.

Welding thin-walled tubes: mainly used for making furniture, toys, lighting fixtures, etc.

Welded special-shaped pipe: Welded steel pipes of various shapes, used for specific occasions.

Spiral welded pipe: mainly used for transportation pipelines of oil and natural gas.

In addition, there are also some special purpose welded steel pipes, such as welded steel pipes for mining fluid transportation and stainless steel welded steel pipes for fluid transportation. These steel pipes have different materials, specifications, and performance requirements based on their specific application scenarios and needs.

In summary, there are many types of welded steel pipes, and the selection needs to be comprehensively considered based on specific application scenarios and requirements.

There are differences between each type of welded steel pipe in multiple aspects, mainly reflected in production processes, structural characteristics, performance, and application scenarios. The following is a detailed analysis of the differences between different types of welded steel pipes:

1. The difference between straight seam welded pipe and spiral welded pipe

Production process:

The production process of straight seam welded pipe is relatively simple, with high production efficiency and low cost. It is usually made from steel plates or strip steel as raw materials, through processes such as curling, welding, and shaping.

The production process of spiral welded pipes is relatively complex, requiring the use of narrow steel plates to be made through processes such as spiral curling and welding. Due to the long length of the weld seam, the production cost is relatively high, but the compressive strength of the weld seam is high.

Structural features:

The weld seam of straight seam welded pipe is parallel to the longitudinal direction of the steel pipe, and the weld seam length is relatively short, usually used for small and medium-sized steel pipes.

The welds of spiral welded pipes are distributed in a spiral shape, with long weld lengths, and are usually used for large-diameter steel pipes.

Performance and Application:

Straight seam welded pipes are mainly used for pile foundation construction in bridge and road engineering, as well as in water supply, drainage, sewage treatment engineering and other fields. It has good corrosion resistance and wear resistance, and can meet various usage requirements under different conditions.

Spiral welded pipes are mainly used in fields such as water conservancy engineering, rainwater and sewage factories, environmental governance, water supply engineering, petrochemical industry, chemical industry, power industry, agricultural irrigation, urban construction, etc. It has high compressive strength and is suitable for large-diameter and high-pressure transmission pipelines.

2. The difference between welded pipes made by different production methods

Electric arc welded pipe:

Features: Made through arc welding process, with high weld quality, suitable for connecting various metal materials.

Application: Widely used in pipeline systems with general requirements.

Resistance welded pipe:

Features: Made by heating the edges of steel plates or strips to a plastic state using resistance heat and then pressing them together, with high production efficiency and low cost. But the quality of the weld seam may be affected by the thickness and material properties of the metal sheet.

Application: Commonly used in the manufacturing of thinner metal sheets or strips, such as pipe supports, frames, etc.

Gas welding pipe:

Features: Using gas flame as a heat source for welding, the process is relatively simple, but the quality of the weld may not be as good as arc welding and resistance welding.

Application: Suitable for welding needs in small-scale operations or specific occasions.

Furnace welded pipe:

Characteristics: Welding is carried out in the furnace, with high production efficiency, but the weld strength is lower than that of electric welded pipes. High energy consumption limits further development.

Application: Mainly used for water and gas pipes, cable protection pipes, and structural pipes.

3. The difference between other special types of welded pipes

Galvanized welded pipe:

Features: Galvanized treatment on the surface of ordinary welded pipes enhances anti-corrosion performance and has a longer service life.

Application: Widely used in occasions that require anti-corrosion performance, such as transporting fluids such as water and gas.

Oxygen blown welded pipe:

Features: Made of high-quality seamless steel pipe material, it has the characteristics of high strength, high hardness, and high wear resistance.

Application: Mainly used in high temperature and high pressure environments such as blowing and delivering oxygen, such as steel smelting, glass production, etc.

Stainless steel welded pipe:

Characteristics: It has good corrosion resistance and high temperature resistance, and can be divided into two categories: seamless pipes and welded pipes according to needs.

Application: Widely used in food processing, chemical industry, petroleum, gas transportation and other fields.

In summary, there are significant differences in production processes, structural characteristics, performance, and application scenarios among different types of welded steel pipes. When selecting welded steel pipes, comprehensive consideration should be given based on specific application scenarios and requirements.