Views: 8 Author: Site Editor Publish Time: 2018-02-28 Origin: Site
We can often see the fire hydrant system in our daily life. And we also use this in everywhere like in building, in warehouse, in Cinema and others. But, do you know how to choose the pipe of fire hydrant system?
In common condition, it used the seamless steel tube to produce, but it should have following requirements. For example, the fire hydrant system body surface should be smooth, bright and clean and the flexible metal case must be without rust, scratches. The door is open easily. The whole case cabinet should be founder and the accessories is complete in the fire hydrant system.About plug valve appearance should be regular without crack and rust.the valve closed or opened flexible and the closed tight,packing is in good condition.It must have factory quality certificate.
Above requirements, we can see the seamless steel tube shall not be bent rust double skin and concave and convex inequality.How to avoid these conditions?
1. Rust removal
Under normal circumstances, we used the acid washing to remove rust of seamless steel tube and we called it chemical derusting. Its principle is to use the acid in the acid washing liquid to react with the seamless steel tube oxide to make the seamless steel tube oxide dissolved, and remove the rust and dirt on the surface of the seamless steel tube. The efficiency of the picking process is high and the rust removal is more thorough, but the pickling process can not reach the surface roughness effect of shot blasting or ball blasting. Pay more attention: seamless steel pickling must wash by enough branch water and do the passivation process. If improper handing will cause the surface of seamless steel pope erosion or the formation of pits.
2. Check ways of seamless steel pipe surface
First we should check seamless steel pipe surface by eyes according to experience, seamless steel pipe rotation, lighting conditions. Then we can use following five ways to test the pipe damage.
A. Ultrasonic flaw detection UT: It is more sensitive to the surface and internal crack defects of all materials with uniform material
B. Eddy current inspection: It mainly test the spot defects(hole shape).
C. Magnetic powder MT and magnetic flux leakage detection: it adapt to detect the surface and near surface flaw with ferromagnetic materials.
D. Electromagnetic ultrasonic flaw detection: it can apply to do the surface inspection in high temperature, high speed and coarse dryness seamless steel tube.
E. Penetrant flaw detection: fluorescence, coloring and detection of surface defects of seamless steel tubes.