Test Methods And Functions Of Stainless Steel Pipe Elbows To Distinguish Materials

Test methods and functions for distinguishing materials of stainless steel pipe elbows:

1. Copper sulfate point test: The copper sulfate point test is a simple method to quickly distinguish ordinary carbon steel from all types of stainless steel. The concentration of the copper sulfate solution used is 5~10%. Before the point test, the elbow test area should be free of grease or various impurities, and a small area should be polished with a soft grinding cloth, and then the copper sulfate solution should be dripped into the cleaned area with a dropper. Ordinary carbon steel or iron will form a layer of surface metallic copper within a few seconds, while the surface of stainless steel will not produce copper precipitation or show the color of copper.

2. Magnetic test: The magnetic test is a simple method to distinguish annealed austenitic stainless steel from ferritic stainless steel. Austenitic stainless steel is non-magnetic steel, but it will have a slight magnetism after being cold worked under heavy pressure; while pure chromium steel and low alloy steel are both strongly magnetic steels.

3. Nitric acid point test: A significant feature of Stainless Steel Weld Elbow is that it is inherently non-corrosive to concentrated nitric acid and dilute nitric acid. This property makes it easy to distinguish from most other metals or alloys. However, high carbon 420 and 440 steels are slightly corroded when subjected to nitric acid point tests. Nonferrous metals will be corroded immediately when encountering concentrated nitric acid. Dilute nitric acid is highly corrosive to carbon steel.