The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Pitting on 304 from different amount of Cl in rubber bands

I would like to know the effect of Cl on pitting of 304 stainless steel. I'm wondering about the amount of Cl environment. Two samples of 304 were put in closed bottles with rubber bands on each bottle. The control experiment was that there was different amount of Cl in each rubber band. Both of them were put in an control environment for standard corrosion testing. The result was that the higher Cl rubber didn't have any pitting while the other got pitting.

Isaratat Phung-on
- Columbus, Ohio, USA
2003

You forgot to include the sulfur content of each, which is as bad or worse than the Cl content.

James Watts
- Navarre, Florida
2003

---

The concentration of Cl in any solution in contact with 304 ss will definitely cause a problem in pitting and surface corrosion. Sulfur, as James says, can also be a problem, but usually a different kind of problem. I am sorry, but I do not totally understand the test you ran. Was the rubber band inside the bottle with the sample of 304? Was it filled with water or what medium? Why a rubber band instead of Cl ions in solution?

Chlorine is always bad for stainless steel, and we have found some of the recent lots of 304 being used in this country to be even worse.

Lee Kremer
Stellar Solutions, Inc.

McHenry, Illinois

2003

What I'm investigating is to see the effect of Cl in rubber band. Each of rubber band has the same amount of sulfur but different amount of Cl. We did try both in water and air (all of them were in closed environment: in closed bottles).

Isaratat
- Columbus, Ohio
2003

If one rubber band has more chlorine in it than another one does, you can bet they are not manufactured identically otherwise. Therefore, you cannot say that they are equal, therefore you can not say that the chlorine has any effect. All that you can say is that band A reacts differently than band B. I know, ---- researchers.

James Watts
- Navarre, Florida
2003

---

2003

I do agree with you, there are not identical. The amount of Cl are significantly different from both bands but the other compositions are not significantly different. Therefore, they should react with samples in different way in which I would like to know how it's different. Unfortunately, I couldn't be able to explain myself with this situation. The results were not what I expected.

Do you have any suggestion about possibility of the reaction differently between this two rubber bands?

Thank you in advance.

Isaratat
- Columbus

I suggest running the test again. The results are so unexpected that I would watch sample control.

Jon Quirt
- Minneapolis, Minnesota
2003