Home /
Search 🔍
the Site
pub Where the world gathers for
plating, anodizing, & finishing Q&As since 1989


Cleaning stainless after production


We are producing stainless a2 and a4 bracket, bolt and through bolt. We are facing problem during cleaning of product after production. Firstly stainless bolts are not coming shiny and it is coming like black color. Can you offer any chemical to this problem. Next problem is for bracket some brown colors are coming like corrosion. We tested raw material it is 100% s/s 304 and 316 grade. Can you offer us acid for both purposes?

Best regards,

Ercument Unal
metals - Jeddah, Saudi Arabia



There are a lot of possibilities here, but it sounds like you are putting a lot of iron and/or other impurities on the surface of the 304/316ss parts that needs to be removed. The colors you are describing do not make sense unless you are heat treating these parts after processing. Is this the case? What kind of cleaner are you using to clean them that is producing the black color? You probably need to remove this by pickling and/or passivation of the parts.

If you give us more information about the process, I am sure someone online here can help you.

lee kremer
lee kremer sig
Lee Kremer
Stellar Solutions, Inc.
supporting advertiser
McHenry, Illinois
stellar solutions banner

finishing.com is made possible by ...
this text gets replaced with bannerText
spacer gets replaced with bannerImages

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

Chemicals &
Consult'g, Train'g
& Software

About/Contact    -    Privacy Policy    -    ©1995-2023 finishing.com, Pine Beach, New Jersey, USA