Classification of pipe fittings

Pipe fittings, especially tees, elbows and heads, are more and more commonly used in the construction of pipeline engineering. This is mainly due to their good forming, strong pressure resistance, and simple welding forms to ensure the pressure of the pipeline. Capacity, so in process pipeline engineering, especially in petrochemical and other high-temperature, high-pressure and flammable and explosive pipelines, the reasonable use of pipe fittings and the quality of the pipe itself directly play a pivotal role.

Because of this, in the pipeline design and installation process, especially in the high temperature, high pressure, and flammable and explosive pipeline projects of the petrochemical industry, no matter from design selection or processing to construction, installation, and inspection, every step of The personnel of the installation unit must strictly control the quality of selection, materials, manufacturing, installation and inspection, otherwise it will cause inestimable losses during the construction and production of the device.

From the construction process, we found that the quality of the arrival of the fittings mainly has the following problems:

1Uneven wall thickness of pipe fittings

The uneven wall thickness of pipe fittings mainly occurs in the parts with large deformation of the pipe fittings. For example, the wall thickness of the back of the elbow is thinner than other parts; the wall thickness of the nozzle and the pipe body is not the same. It is stipulated in relevant standards. The wall thickness reduction of the pipe fittings must not exceed 12, 5 of its nominal thickness, but it was found on site that some wall thickness reductions reached 2o-30. For the inspection of such problems, it is often difficult to find them with measuring tools such as calipers. At this time, it can only be detected by using an ultrasonic thickness gauge.

2 Hardness exceeded

The problem of excessive hardness is mainly due to the problem of the heat treatment process after forming. The solution is to use the correct heat treatment process for another heat treatment. This problem can usually be solved

3 defects in materials and processing

Such problems have a great impact on the safety of the device. It's more troublesome to check. There are many factors that cause defects, and they are more complicated. It has both defects in the material itself, problems in the manufacturing process, and defects caused by incorrect heat treatment processes. So why do they cause safety hazards and how to avoid such problems? Now take the three links as an example to analyze this one by one.