Characteristics and applications of seamless steel pipes among stainless steel pipes

Stainless steel pipes can be mainly divided into two types: seamless steel pipes and welded seamed steel pipes. According to the cross-sectional shape, it can be divided into round pipes and special-shaped pipes. The most widely used ones are circular steel pipes. In addition, the shapes of special-shaped steel pipes are mostly square, rectangular, semicircular, hexagonal, equilateral triangle, octagon, etc.
If the steel pipe needs to withstand fluid pressure, a hydraulic test needs to be performed on this type of pipe to check its quality and pressure resistance. It is qualified only if there is no liquid leakage, pipe wetting or expansion under the specified pressure, and some stainless steel The pipe also needs to undergo tests such as curling, flaring and flattening according to corresponding standards or requirements of the buyer.
The characteristics of stainless steel pipes can be seen from the following aspects. First, through chemical analysis of the chemical composition of the stainless steel material, to see whether the chemical composition complies with the standards. Secondly, the pressure-resistant pipes can also be tested one by one through air pressure and water pressure tests. If the specified pressure value is not maintained for no less than 5 seconds, there will be no leakage. The conventional supply water pressure test is 2.45MPa. The air pressure test is P=0.5MPAa. Corrosion tests are also required. All industrial corrosion-resistant steel pipes supplied are tested for corrosion resistance in accordance with standards or corrosion methods agreed upon by both parties, and the stainless steel pipes must not have intergranular corrosion tendencies. In terms of process performance inspection, experiments such as flattening, stretching, impact, flaring, hardness, metallography, and bending are all necessary.
Seamless steel pipes are made of steel ingots or solid tube blanks through perforation, and are then processed by hot rolling, cold rolling or cold drawing. Therefore, generally seamless steel pipes can be divided into hot-rolled and cold-rolled seamless pipes. Two types of steel pipes. In addition, its specifications are usually expressed in millimeters of outer diameter and wall thickness.
Among them, hot-rolled seamless steel pipes include general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes and other steel pipes.
In addition to general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, and petroleum cracking pipes, cold-rolled seamless steel pipes also include carbon thin-walled steel pipes, alloy thin-walled steel pipes, and stainless thin-walled steel pipes. Steel pipes, special-shaped steel pipes, etc.
The outer diameter of hot-rolled seamless steel pipes is usually greater than 32mm, and the wall thickness is basically 2.5-75mm. The diameter of cold-rolled seamless steel pipes can be as small as 6mm, the wall thickness can be as thin as 0.25mm, and the outer diameter of thin-walled stainless steel pipes can reach 5mm, the wall thickness can be less than 0.25mm, and the accuracy of cold-rolled stainless steel pipes is higher than that of hot-rolled sizes. With the development of social economy, the scope of use of stainless steel pipes has become increasingly widespread.