Previous in Forum: What Alloy Has the Same C of TE as Borosilicate Glass & Pyrex?   Next in Forum: Cotton Crop Waste
Close
Close
Close
12 comments
Participant

Join Date: May 2012
Posts: 3

Carbon/Stainless Cross Contamination

05/10/2012 3:12 PM

I've been told there are kits to use to see if there is cross contamination between Carbon and Stainless steel. Does anyone have any information? I would like one of my suppliers to verify there is no cross contamination of the stainless prior to shipping.

Thanks,

Gary

Register to Reply
Pathfinder Tags: Cross contamination
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".
Guru
New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: Auckland, New Zealand
Posts: 8778
Good Answers: 376
#1

Re: Carbon/Stainless Cross contamination

05/10/2012 3:17 PM

What level of cross contamination are you looking for? Heavy cross contamination (for example a damaged steel press contaminating pressed stainless steel fittings) can be detected visually (the stainless steel shows signs of rust) and with magnets.

Small levels of contamination, well I am not sure.

__________________
jack of all trades
Register to Reply
Participant

Join Date: May 2012
Posts: 3
#2
In reply to #1

Re: Carbon/Stainless Cross contamination

05/10/2012 3:19 PM

The contamination is rust, but not showing up until a couple of weeks later.

Thanks,

Register to Reply
Guru
New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: Auckland, New Zealand
Posts: 8778
Good Answers: 376
#3
In reply to #2

Re: Carbon/Stainless Cross contamination

05/10/2012 3:33 PM

Oh we have had this problem numerous times with pressed stainless steel washers, contamination due to worn steel press dies pressing steel into the stainless steel (which then rusts). Inwards goods quality checking picked up the problems and the stock was sent back and the supplier notified to check and fix worn press dies.

Rust takes time to show itself, but you should be able to speed up the rusting process by storing the samples in a high humidity environment. Previously we used an enclosed container (be it an old refrigerator or even a shipping container), added a salt to a container of water to raise the humidity and installed a fan or two to circulate the humid air. Results may vary but you should be able to get a much quicker idea than just waiting (I can't remember the name of the salt, but it wasn't toxic or expensive).

As for a quick chemical test, well there probably is one to test for iron or something but I have no experience with this method. Have you tried an internet search?

__________________
jack of all trades
Register to Reply
Guru

Join Date: Oct 2008
Posts: 42294
Good Answers: 1662
#4

Re: Carbon/Stainless Cross Contamination

05/10/2012 8:57 PM

What specification controls the procurement and incoming inspection of the raw stock when it comes to you.

The supplier will want more money to for additional testing and certification.

Are you sure the "rust" is caused before it gets to you?

Register to Reply
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 22698
Good Answers: 410
#10
In reply to #4

Re: Carbon/Stainless Cross Contamination

05/11/2012 9:29 AM

Your correct.

Alot is in the proceedures.

I set up a company for ASME. And on the weld proceedures, included about the avoidance of filler rod containmination (Dropping on the floor) , plus quality proceedures such as, type of wire brushes to clean welds, wiping off fab equipment befor used, such as pinch rollers.

Details such as this that are in your quality program reduces the incidents, but doesn't eliminate them.

And of course the only way contamination shows up to correct this that I know of is time.

PS

Just read the following post.... great posts and GA

__________________
“ When people get what they want, they are often surprised when they get what they deserve " - James Wood
Register to Reply
3
Member

Join Date: Sep 2009
Posts: 7
Good Answers: 1
#5

Re: Carbon/Stainless Cross Contamination

05/10/2012 11:12 PM

Brushing a solution of copper sulphate over the stainless steel will produce a reaction with any iron present, producing a copper film which stands out clearly in relative to the colour of the stainless. I have used this method successfully for determining whether a ground surface has removed the stainless cladding from carbon steel boiler tubes. Smaller "spots" of contamination (eg grinding overspray from adjacent carbon steel, a common problem) may be too small to show up so clearly, but worth a try. The test is very quick, with colour change apparent within seconds.

Register to Reply Good Answer (Score 3)
5
Power-User

Join Date: Mar 2009
Location: Sydney, Australia.
Posts: 122
Good Answers: 11
#6

Re: Carbon/Stainless Cross Contamination

05/11/2012 12:18 AM

I remember that we used the ferroxyl test here and Googling it up produced a number of hits including From BRITISH STAINLESS STEEL ASSOCIATION:

Corrosion & Oxidation

1. Iron contamination and rust staining on stainless steel

Rust staining can occur and has been reported as anything from a slight brown 'bloom' on the surface to severe surface pitting or rusty scour marks on items such as handrails. These effects are usually due to surface contamination from contact with non-stainless steel items. Iron contamination can be costly to remedy, and is avoidable. The ferroxyl test can be used to detect 'free' iron contamination. (108)

2. On-site methods for stainless steel grade product sorting

Guidance on methods for sorting stainless steels from low alloy and carbon steels is shown. These include physical (colour, density, magnetic) and mechanical (hardness) properties and chemical tests (copper sulphate, copper chloride, nitric acid and sulphur tests). A suggested approach to a step-by-step procedure for differentiating stainless steels from carbon steels is tabulated. These methods have not been verified by the BSSA, who take no responsibility for their accuracy of the conclusions reached on steel types.

3. Salt spray testing of stainless steels

Salt spray testing is an accepted method for assessing the suitability of stainless steel parts and fabrications that are likely to encounter chloride environments in service. The test outcome is sensitive to the shape of the parts (designed-in crevices), surface finish and the test conditions and so specific results for 'hours to failure' for steel grades alone is not appropriate. Specified test methods are shown.

and this: The so-called ferroxyl test is described in ASTM A 380, "Practice for Cleaning ...

and this:

LMATS is NATA accredited to perform Ferroxyl test in accordance with ASTM A380 and ASTM A967.

This test is a highly sensitive test and should be performed when no traces of free iron or iron oxide is acceptable on the Passivated items. The test can be used on stainless steel to detect iron contamination, including iron-tool marks, residual-iron salts from pickling solutions, iron dust, iron deposits in welds, embedded iron or iron oxide, etc.

Due to the use of Potassium Ferricynide this test method cannot be employed in the food industry.

Contact LMATS Melbourne or Sydney laboratory staff for your ferroxyl test or contamination detection test or corrosion resistance test.

I believe that the chemicals involved are to be respected - use due care.

Register to Reply Good Answer (Score 5)
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 30332
Good Answers: 818
#7

Re: Carbon/Stainless Cross Contamination

05/11/2012 3:12 AM

So, pressing the source of this information for further details of the kits being discussed is out of the question, then?

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Participant

Join Date: May 2012
Posts: 3
#8
In reply to #7

Re: Carbon/Stainless Cross Contamination

05/11/2012 8:58 AM

http://citrisurf.com/CuSO4info.htm

http://citrisurf.com/products.htm

Some links for kits that one of my suppliers is using.

Thanks for all or your help.

Register to Reply
Power-User

Join Date: Mar 2009
Location: Sydney, Australia.
Posts: 122
Good Answers: 11
#11
In reply to #7

Re: Carbon/Stainless Cross Contamination

05/13/2012 6:48 PM

If "So, pressing the source of this information for further details of the kits being discussed is out of the question, then?" was directed at my post then:

We used the ferroxyl test in a nuclear reactor construction project with the associated testing being done >6 years ago. The test medium was made up by a chemist associated with the project. I have only ever see a bottle of the solution but haven't actually used it.

If IrishGary would like to make his own test medium up, I will see if I can track down the formula and any instructions etc - not too optimistic though (the knowledge may be with the long gone construction team). IrishGary - let me know if you need to persue this.

There are plenty of hits for "ferroxyl test kit" on Google - check them out. In checking this aspect out today, I looked here http://www.stainlessfoundry.com/FreeIron.asp and found this:

Detecting Free Iron ...

3. Use the "ferroxyl test." Spray the surface with a solution of potassium ferricyanide. If free iron is present, a blue color will appear. This test is extremely sensitive and often gives false positive results, that is, it gives an indication of iron being present when it really is not. The ferroxyl solution must be made fresh each day.
Both the copper sulfate and the ferroxyl tests are described in ASTM A380.

It would be worth chasing up ASTM A380 and I remember that we always used a fresh batch of the solution (as above).

Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 30332
Good Answers: 818
#12
In reply to #11

Re: Carbon/Stainless Cross Contamination

05/15/2012 3:52 AM

No, it wasn't.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru

Join Date: Sep 2006
Location: Western Pennsylvania, USA
Posts: 762
Good Answers: 9
#9

Re: Carbon/Stainless Cross Contamination

05/11/2012 9:15 AM

I visit some vendors who use Stellar Products and have for years.

An excellent source for user and environmentally friendly products.

Register to Reply
Register to Reply 12 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".
Copy to Clipboard

Users who posted comments:

dclarihew (1); IrishGary (2); jack of all trades (2); lyn (1); Malcolm Stephen (2); phoenix911 (1); PWSlack (2); qaqcpipeman (1)

Previous in Forum: What Alloy Has the Same C of TE as Borosilicate Glass & Pyrex?   Next in Forum: Cotton Crop Waste

Advertisement