Butt welding elbow in the incorrect use can produce the phenomenon of corrosion, welding curved hairs students after corrosion, usually for the butt welding elbow pipe wall thinning, local pits and pitting. Butt welding elbow after the corrosion detection methods: leakage flux method was used to detect the basic principle is based on the fundamental features of high permeability of ferromagnetic materials.
Butt welding elbow corrosion defect of permeability is much smaller in butt welding elbow permeability, butt welding elbow under the action of an external magnetic field is magnetized, when when there are no defects in butt welding elbow, the lines of magnetic force is, for the most part, through the pipe. At the same time, the uniform distribution of magnetic force lines; when butt welding elbow internal defects, the magnetic field lines are curved and part of the magnetic flux leakage of leakage of pipe surface. Detection by magnetic flux leakage magnetic elbow surface escape, you can judge the existence of defects. Ultrasonic ultrasonic testing is the use of ultrasonic pulse reflection principle to measure the thickness of the tube wall after corrosion. The process is formed by self – propagating centrifugal casting, which mainly uses the chemical reaction of the material itself, the heat release from the heat release to produce high temperature, and the technology of synthesizing the new material in the process of the spread of the combustion wave. Detection probe perpendicular to the inner wall of the butt welding elbow to emit ultrasonic pulses, first to receive the probe is composed of a pipe wall inner surface reflection pulse and ultrasonic probe and received from the tube outer wall surface reflection pulse, the pulse distance of space between the inner and surface reflection pulse reflected the tube wall thickness. Simmer bending: refers to the tube are processed into a butt welding elbow, generally refers to professional hydropower electrical metal pipe and PVC pipe threading; simmer butt welding elbow: multiple fingers to drainage professional metal butt welding elbow tubule diameter welded elbow can obtained by bending.
Cold / hot bending elbow: general small and medium size can be obtained with large diameter bending; bending needs. Bending processing generally refers to the scene. Butt welding elbow: Engineering water-supply system using the most (especially large pipe diameter) can buy finished welded elbow, processing method is stamping.
Source: Yaang Pipe Industry(www.yaang.com)