Rusted 304 stainless steel tube
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The 304 stainless steel tube I just bought has a very smooth outer surface, while its inner surface is almost completely covered with red rust. It is non-magnetic; no pink color appears when tested with stainless steel test solution, so 201 stainless steel can be ruled out. I had only used stainless steel plates before; I had never encountered 304 stainless steel that was covered in rust like this. I would like to ask the experts why this happens.
This post was last edited by 1111111 on 2017-12-24 at 14:48. Is there rust on the 304 pipe? . . It’s good to have rust; let the rust tease you a bit, I support it. . . You don’t want to agree, do you? , :P . . Bro, I guess you don’t even know what rust looks like
“”It’s ‘unlikely’ to be contaminated by carbon steel; it’s the inner surface of the stainless steel pipe that is severely corroded, while the outer surface is in good condition. Is it possible that it’s second-hand, sold to customers after having its surface polished, or some other type of low-quality stainless steel pipe?
Stainless steel can also be corroded under certain conditions
To save money, I bought refurbished pipes
The steel pipe is new and there’s no problem with it; the red color is simply due to the acid washing process not being thorough enough inside the pipe. This is a common issue among some stainless steel pipe manufacturers (many in Zhejiang province) – they are just not thorough enough during the acid washing process. It generally doesn’t affect usability, so it’s no concern
Friend, please don’t slander the stainless steel industry in Zhejiang. This is the result of his desire to save money; you get what you pay for – that’s the truth.