Seamless steel pipe quality appraisal

Seamless steel pipe is a long steel product with a hollow section and no welded seams. It is made by different processes such as hot rolling, cold rolling or cold drawing. Since there are no seams in the entire pipe wall, seamless steel pipes exhibit better integrity and uniformity, which gives it advantages in strength, toughness and sealing. These properties make seamless steel pipes ideal for use in pipes or vessels under pressure and in applications requiring high strength and impact resistance.
seamless steel pipe materials include carbon steel, alloy steel, stainless steel, etc. These materials can meet the specific requirements of many industrial fields such as petroleum, chemical industry, boilers, electric power, and shipbuilding. Especially in high pressure, high temperature or corrosive environments, the reliability and safety of seamless steel pipes are particularly critical. Although seamless steel pipes have many advantages, they still require regular inspection and maintenance during use to ensure their continued performance and long life.
In seamless steel pipe quality appraisal cases, Zhongke Testing can provide seamless steel pipe quality appraisal services.

1. According to the cross-sectional shape: round welded pipe, special-shaped (square, flat, etc.) welded pipe.
2, classified by wall thickness: thin-walled steel pipes, thick-walled steel pipes.
3. According to different materials and uses: ordinary carbon steel seamless steel pipes, carbon structural steel seamless steel pipes, alloy steel seamless steel pipes, stainless steel seamless steel pipes, seamless steel pipes for petroleum cracking, core straight seam welded special-shaped steel pipes.
4, divided according to special purposes: seamless pipes for boilers, chemical and electric power, and petroleum transportation.
5, divided according to the manufacturing method: hot-rolled (extruded) pipe, cold-drawn (rolled) pipe, and top-made wire casing.

GB/T 43105-2023 Seamless steel pipe for hydroforming parts
GB/T 5310-2023 Seamless steel pipe for high-pressure boilers
GB/T 24512.2-2009 Seamless steel pipe for nuclear power plants Part 2: Alloy steel seamless steel pipe
GB/T 9808-2008 Seamless steel pipe for drilling
GB/T 18248-2021 Seamless steel pipe for gas cylinders
GB/T 8162-2018 Seamless steel pipe for structure
GB/T 8163-2018 Seamless steel pipe for transporting fluids
GB/T 9948-2013 Seamless steel pipe for petroleum cracking
GB/T 28883-2012 Composite seamless steel pipe for pressure bearing
GB/T 3090-2020 Stainless steel small diameter seamless steel pipe
0GB/T 14975-2012 Stainless steel seamless steel pipe for structure
1

A petrochemical company customized a batch of seamless steel pipes from a steel pipe factory. When the goods arrived, the steel pipe company was responsible for pressure testing and found leaks in 6 or 7 pipes. After that, the steel pipe company carried out maintenance and tested the pressure normally. However, after about a week of normal operation of the petrochemical company, four leaks occurred in the steel pipes with consistent cracking conditions, which had a huge impact on production work. As a result, the two parties had conflicts and disputes over the quality of the steel pipes and went to court. The court commissioned an appraisal agency to investigate and verify the quality of the steel pipes. When the
expert team inspected the site, they found traces of repair welding on the surface of the leaking steel pipe, but there were still obvious cracks inside. The expert team conducted a fracture analysis on the crack in the steel pipe and found that the crack ran through the entire wall thickness of the steel pipe and had a flat cross-section with no signs of tearing. It can be seen that the crack in the steel pipe occurred during the manufacturing process and was not caused by external force.
After that, the expert team took samples and returned them to the laboratory for analysis and testing, and finally confirmed the analysis results. The quality of this batch of steel pipes did not meet the national standards.
This conclusion constitutes the final identification result and was adopted by the court.