plating, anodizing, & finishing Q&As since 1989
Alternate to acid pickling of Stainless Steel Strips
June 5, 2012
Q. I am Adish Jain, small scale manufacturer of stainless steel strips in Delhi. Can anyone suggest me an alternate to acid pickling of Stainless Steel Strips as in India we face lot of challenges due Environmental pollution. Below are steps taken to produce stainless steel strips at our manufacturing unit.
1) Flat to 18 Gauge (Hot rolling )
2) Pickling (chemicals used HF, N and S) done in a tank
4) 18 Gauge to 22 Gauge (rolling)
5) Annealing and Pickling
6) 22 Gauge to 26 Gauge (Cold rolling)
7) Pin pass
8) Annealing and Pickling
9) Skin Pass
Dimensions of final product
Thickness : 26 Gauge
Length : 80 inches
Width : 11 - 24 inches
- Delhi, India
A. Hi Adish. Sorry, but you've abbreviated beyond my ability to follow you. "N and S"? Nitric acid and sulphuric acid, maybe?
If H2O2 can be used as the oxidizing agent in the pickling process, it decomposes to water and oxygen, which may be less problematic than nitric acid. If scale buildup can be minimized in the annealing process, that should help too. I'm not aware of any gaseous etch process for scale removal, but there may be one.
Although it is very difficult to do a real environmental pollution comparison between two processes, remember that a reject is 100% waste and there is nothing more polluting and wasteful than 100% -- so don't implement changes based on touchy-feely vagaries. Unless the new process actually works better and more reliably in the shop, you're probably going the wrong way. Good luck.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey