These features of seamless stainless steel elbows should be avoided!
With the increasing number of stainless steel seamless elbow manufacturers, the authenticity of materials has become difficult to distinguish. In order to prevent lightning strikes and avoid pitfalls, one must learn to observe the following characteristics!
1. Material fraud (stealing beams and replacing pillars)
201 impersonates 304/316: genuine 304 stainless steel contains 18% chromium and 8% nickel, with a silver white and shiny appearance, while counterfeit products have a chromium content of<15%, nickel content of<1%, and a gray and dark color. Dilute nitric acid can be used for identification. If a fake product is purchased, it may rust through and leak water within six months. Chemical pipelines should be even more vigilant about causing leakage accidents.
Fake and inferior 200 series’ ground bar steel ‘: excessive addition (national standard ≤ 5.5%, inferior products up to 7.5%), long-term exposure can harm health.
2. Process defects (no welding filling)
Weld camouflage: Poor quality elbows have fine welding lines on the inner wall, and the outer wall is polished and covered.
Shrinkage of wall thickness: Only 4.2mm measured on a 5mm scale resulted in a 30% decrease in pressure bearing capacity. Measure the thinnest point at the bend with a caliper for inspection.
3. Performance Hardship (High Voltage Thunder)
In terms of compressive strength, low-quality elbows with a pressure of 20MPa may experience weld cracking.
In terms of corrosion resistance: Poor quality elbows corrode in dilute sulfuric acid for 10 minutes.
In terms of high temperature stability: Poor quality elbows undergo oxidation and embrittlement of welds at 400 ℃.
Also, do not buy anything without a material report, inspection certificate, or precise wall thickness!
These features of seamless stainless steel elbows should be avoided!
With the increasing number of stainless steel seamless elbow manufacturers, the authenticity of materials has become difficult to distinguish. In order to prevent lightning strikes and avoid pitfalls, one must learn to observe the following characteristics!
1. Material fraud (stealing beams and replacing pillars)
201 impersonates 304/316: genuine 304 stainless steel contains 18% chromium and 8% nickel, with a silver white and shiny appearance, while counterfeit products have a chromium content of<15%, nickel content of<1%, and a gray and dark color. Dilute nitric acid can be used for identification. If a fake product is purchased, it may rust through and leak water within six months. Chemical pipelines should be even more vigilant about causing leakage accidents.
Fake and inferior 200 series’ ground bar steel ‘: excessive addition (national standard ≤ 5.5%, inferior products up to 7.5%), long-term exposure can harm health.
2. Process defects (no welding filling)
Weld camouflage: Poor quality elbows have fine welding lines on the inner wall, and the outer wall is polished and covered.
Shrinkage of wall thickness: Only 4.2mm measured on a 5mm scale resulted in a 30% decrease in pressure bearing capacity. Measure the thinnest point at the bend with a caliper for inspection.
3. Performance Hardship (High Voltage Thunder)
In terms of compressive strength, low-quality elbows with a pressure of 20MPa may experience weld cracking.
In terms of corrosion resistance: Poor quality elbows corrode in dilute sulfuric acid for 10 minutes.
In terms of high temperature stability: Poor quality elbows undergo oxidation and embrittlement of welds at 400 ℃.
Also, do not buy anything without a material report, inspection certificate, or precise wall thickness!