Brittle fracture is caused by a variety of reasons. For example, when there are precipitates on the grain boundary, no matter their strength is stronger or weaker than that of the matrix, it is the cause of cracks; the segregation of inclusions on the grain boundary is also the cause of fracture; in addition, even at the intersection far less than the yield limit Under the action of variable load, fatigue fracture will also occur. During the low-stress brittle fracture that occurs in high-strength metallic materials, the material structure is far from homogeneous and isotropic.

The cracking of stainless steel flanges is due to the presence of a large number of non-metallic inclusions in the forging billets used to make the flanges during the forging process, and the volumetric inclusions are repeatedly forged into regional inclusions, resulting in forging cracks along the tip of the inclusions in the material, forging After forging, the larger inclusions turn into larger cracks, and the smaller inclusions turn into smaller microcracks after forging.

High-frequency quenching requires that the matrix is mainly pearlite after normalizing, and it is cooled by water spray or polyvinyl alcohol solution; the tempering temperature is 200-400 ℃, and the hardness is 40-50HRC, which can ensure the hardness and wear resistance of the surface of the square tube.

We all know that the welding process of ssaw steel pipe is a more critical aspect in the process of processing and production. Only after strictly controlling the craftsmanship can we ensure that the overall surface workmanship will be better, and achieve the trust and recognition of customers in the process of sales. Therefore, what problems should be paid attention to in the welding process?

Rectangular tubes are widely used in our daily life. It can be said that steel pipes not only reduce the weight of supports, save building materials, but also make construction easier and easier. So, how to identify fake and inferior rectangular tubes?

The performance of the thick-walled square tube determines its use.In recent years, the thick-walled square tube has been used in the truss structure of airport terminals, stadiums and exhibition centers due to its beautiful appearance, reasonable stress and relatively simple node handling. It is widely used as a steel member in the system and curtain wall support system.

LSAW steel pipes have several flaw detection tests. LSAW steel pipes are now used more and more widely. According to different projects, the standards for using steel pipes are also different. Generally speaking, steel structures, piling, sewage discharge pipes, etc. There is no requirement for flaw detection of steel pipes, no need for flaw detection.

High-frequency welded pipes (ERW) need to go through a series of processes from raw materials to finished products. The production process flow mainly depends on the product variety. The completion of these processes requires various mechanical equipment and welding, electrical control, and testing devices. These equipment and devices are in accordance with different The technological process requires a variety of reasonable arrangements.

The submerged arc welding process(SAW) is suitable for the requirements of heavy industrial applications such as pipelines, pressure vessels and tanks, locomotive manufacturing, heavy construction, and excavation. It is suitable for industries that require high productivity, especially those involving very thick materials, and can be buried from There are many benefits obtained in the arc welding process. Its high deposition rate and walking speed have a significant impact on the productivity, efficiency and production cost of workers. This is also one of the key advantages of the submerged arc welding process. Other benefits include: Excellent chemical composition and mechanical properties, improved working environment comfort and good weld shape and weld toe line.

The carbon element in the seamless steel tube (smls) has a great influence on its own performance, so when the seamless tube is decarburized, its service life will be greatly reduced, and if the surface of the seamless tube is decarburized If it is not cleaned, the hardness and wear resistance of the surface layer of the seamless pipe will be reduced, and during quenching, cracks will be formed on the surface of the workpiece due to the different volume changes of the inner and outer layers. Therefore, how to prevent the surface decarburization of seamless pipes is a problem that should be paid attention to in the production process.

At present, large-diameter thick-walled steel pipes, large-diameter thick-walled seamless steel pipes, small-diameter thick-walled seamless steel pipes, special thick-walled steel pipes, large-diameter coiled pipes, thick-walled coiled pipes and other series of thick-walled steel pipes have been formed. It replaces the same standard imported steel pipe and is applied to hydraulic system piping.

After removing the root of the weld, double-sided weldments should be inspected. When using the oxyacetylene flame to cut the welding fixture on the alloy pipe that has a tendency to harden, defects in the ground part will be found. Radiographic testing and ultrasonic testing The main targets of radiographic testing and ultrasonic testing are the butt joints of straight seam steel pipes and the butt joints of butt welded pipe fittings.

In order to improve the performance of stainless steel pipe (ss pipe), it is often necessary to adopt certain cold working methods, such as cold drawing, cold rolling, cold rolling, cold bending, cold expansion, cold twisting, etc., which can achieve a certain effect, but also cause a certain amount of damage. Cold working is actually like welding, which will inevitably damage the performance of stainless steel pipes, especially the corrosion resistance or heat resistance.

7 steps for pickling and passivation of stainless steel pipes.