After the corrosion of the welded elbow, the wall thickness of the welded elbow will generally become softer, producing some dents and black spots. Detection methods after corrosion of welded elbows:The principle of leakage detection is based on the basic characteristics of high permeability of ferromagnetic materials.
Welded elbow corrosion defects in the magnetic permeability is much smaller than the welded elbow, welded elbow demagnetization under the action of the external magnetic field. When the welded elbow is flawless, the vast majority of the magnetic induction line through the seamless steel pipe, the magnetic induction line is uniformly distributed; when the welded elbow is flawed, the magnetic induction line bends, and part of the magnetic induction line leaks from the surface of the seamless steel pipe. According to the magnetized welded elbow surface leakage, you can determine the presence of defects. Ultrasonic testing uses the ultrasonic principle of single pulse reflection to accurately measure the thickness of the pipe wall after corrosion. The technology uses the method of self-diffusion squeeze casting, the key is to use the chemical change of the chemical substance itself, according to the exothermic reaction to ignite the sustained high temperature, in the process of combustion wave propagation to produce new substances. During inspection, a camera sends a single pulse of ultrasonic waves perpendicular to the inner cavity of the welded elbow. The camera first receives a scattered single pulse from the inner wall thickness, and then the ultrasonic probe receives a scattered single pulse from the surface of the wall thickness. The distance between the single pulse and the single pulse from the inner reflection surface reflects the wall thickness.
Elbow daily maintenance methods: elbow gate valve packing gland nut should be evenly tightened, shall not be rolled into a curved state to prevent impact, preventing the seat fitness movement, and even cause leakage. Elbow should be the spindle, try not to use the rod or other special tools to prevent damage to the gate valve parts. The spindle is canceled clockwise, otherwise open.
