Pickling passivation is a chemical reaction used to remove rust from seamless steel pipes surfaces. The steel pipe is fully pickled and passivated to remove all kinds of oil stains, rust, oxide scale, welding spots and other dirt, and the surface becomes uniform silver-white after treatment, which greatly improves the corrosion resistance.

The technical requirements of stainless steel pipes include surface quality, mechanical properties, corrosion resistance and process performance.

The essence of high-temperature temper brittleness of seamless pipes is generally considered to be the result of the segregation of impurity elements such as phosphorus, tin, and antimony at the prior austenite grain boundaries, resulting in the embrittlement of the grain boundaries.

In the process of pile driving, the top of the pipe pile is prone to concrete drop angle, cracking, collapse or even the steel bar on the top of the pile is completely exposed and damaged. What are the reasons and preventive measures for this phenomenon?

By heating the seamless steel pipe to about 550~850 °C, after a constant temperature for one time, the carbon metal and other various alloys are uniformly dissolved in the austenite. , through the rapid cooling of quenching water, carbon and other alloys have no time to precipitate, and pure austenite structure is obtained, which is called solid solution treatment.

With the advancement of welding and inspection technology, the quality of welds has been continuously improved, the varieties and specifications of welded steel pipes have been increasing, and seamless steel pipes have been replaced in more and more fields.So what should be paid attention to in the installation process of welded pipes?