Resistance welded steel pipes (ERW steel pipes) are widely used in industries such as construction, automobiles, and oil and gas. Due to their superior performance and economy, the market demand is growing. However, the quality of ERW steel pipes directly affects their performance in various application scenarios, so strict quality control and inspection methods are essential during the production process.

1. Quality Control in ERW Steel Pipe Production
Raw Material Control
The quality of ERW steel pipes depends first on the selection of raw materials, and high-quality hot-rolled coils are usually used as raw materials. To ensure that the chemical composition and mechanical properties of the steel pipe meet the requirements, manufacturers need to conduct strict inspections of the raw materials. This includes chemical composition analysis, tensile tests, impact tests, and yield strength tests of the raw materials.

Welding process control
The core production process of ERW steel pipes is high-frequency resistance welding (ERW), and its quality control is crucial. During the welding process, the stability of welding current and voltage has a direct impact on the formation and strength of the weld. Therefore, manufacturers need to use advanced automation equipment to monitor parameters such as welding current, voltage, and weld temperature in real time to ensure welding quality. At the same time, the weld seam during the welding process must be kept uniform, and the welding line must be neat and without dislocation to avoid defects such as pores and cracks.

Tube forming control
During the forming stage of ERW steel pipes, the steel plate is bent into a tube through a series of forming rollers. In this process, the forming accuracy has a great influence on the roundness, straightness and other indicators of the final pipe. To ensure that the size and shape of the steel pipe meet the standards, manufacturers usually use a laser measurement system to detect the size, thickness and surface flatness of the pipe in real time.

Heat treatment and weld annealing
In order to improve the strength and toughness of ERW steel pipes, the weld seam is usually annealed. During the annealing process, the temperature and heating time need to be strictly controlled to ensure that the metallographic structure of the weld is optimized, eliminate welding stress, and avoid quality problems such as weld brittle cracking.

Anti-corrosion treatment
For ERW steel pipes used in corrosive environments, surface anti-corrosion treatment is also required, such as galvanizing, coating or cladding materials, to improve the corrosion resistance of the steel pipe. The quality of anti-corrosion treatment also needs to be controlled by appropriate detection methods.

2. Inspection methods of ERW steel pipes
Non-destructive testing (NDT)
The quality inspection of ERW steel pipes usually adopts non-destructive testing (NDT) methods to avoid damage to the product. Common non-destructive testing methods include ultrasonic testing, X-ray testing and magnetic particle testing.

Ultrasonic testing: Ultrasonic testing is the most commonly used method to detect weld defects. Through the ultrasonic probe, the inspector can identify whether there are defects such as pores, inclusions or cracks inside the weld to ensure the integrity of the weld.

X-ray testing: X-ray testing is mainly used for in-depth analysis of steel pipe welds, especially for detecting pores, inclusions and cracks in welds. Compared with ultrasonic testing, X-ray testing can provide more intuitive images and accurately identify potential quality problems.

Magnetic particle testing: Magnetic particle testing is a detection method for surface defects of welds, mainly used to detect surface cracks, weld dislocation and other problems. Magnetic particle testing is suitable for welds of magnetic materials, but its detection ability for internal defects is limited.

Hydrostatic testing
Hydrostatic testing is an important means to detect the pressure bearing capacity of ERW steel pipes. By filling the steel pipe with water and applying a certain pressure, the inspectors can evaluate whether the steel pipe will deform or leak under high pressure conditions, so as to determine whether its pressure resistance is qualified. Water pressure testing is an essential quality inspection item in the pipeline industry.

Dimension and appearance inspection
In order to ensure that the size of the ERW steel pipe meets the customer's requirements, the manufacturer will measure the outer diameter, wall thickness, length and roundness of the steel pipe. Generally, special measuring tools or automated equipment are used for inspection and the inspection data is recorded.

In terms of appearance inspection, the inspectors will visually inspect the surface of the steel pipe for scratches, indentations, depressions, cracks and other appearance defects. Especially for steel pipes after anti-corrosion treatment, it is also necessary to check whether the anti-corrosion layer is evenly covered and whether there are bubbles or peeling.

Mechanical property test
In order to ensure that the ERW steel pipe has sufficient strength and toughness, the manufacturer usually conducts a series of mechanical property tests, including tensile tests, bending tests, impact tests, etc. These tests evaluate the mechanical properties of the steel pipe under different conditions by simulating the stress state under actual working conditions.

Chemical composition analysis
The chemical composition directly affects the performance and service life of steel pipes, especially in high temperature, high pressure or corrosive environments. Therefore, manufacturers will conduct chemical composition analysis on steel pipes to ensure that they contain appropriate amounts of carbon, sulfur, phosphorus and other elements to achieve the expected use effect.

III. Conclusion
The quality control and testing methods of ERW steel pipes are directly related to the performance and safety of the products. In the production process, the manufacturing quality of steel pipes can be guaranteed through strict raw material control, welding process control, forming accuracy control, weld annealing and anti-corrosion treatment. In terms of quality inspection, non-destructive testing, water pressure testing, dimensional testing and mechanical properties testing are used to ensure that the steel pipes meet the standard requirements.

An efficient quality control and testing system not only improves the service life and safety of ERW steel pipes, but also provides reliable guarantees for downstream users, thereby improving the product level of the entire industry.
To learn more, please visit the website: https://www.baowi-steel.com/products/casing-and-tubing.html