We all know that industrial welded pipes require annealing treatment, but how can we know if stainless steel welded pipes are annealed? Today, the editor will teach you how to distinguish between annealed and non annealed stainless steel welded pipes.

1. Echo judgment for pipes

Tap each tube and listen for the echo at the opening. If the echo is high and sharp, it indicates that it has been annealed. Because the internal crystal structure of the annealed piece is relatively uniform and dense, it can produce high pitch echoes. However, without annealed parts, due to the presence of numerous structural defects, they can absorb some of the acoustic energy, resulting in a lower sound at the nozzle and a slight blockage.

2. Use a digital multimeter with good accuracy to measure the resistance of each unit length with the same length

Generally speaking, stainless steel has a high resistance and can be measured

The resistance value of annealed steel parts is smaller than that of non annealed ones

Be sure to wipe dry and free of liquid before measuring