Galling of 303 vs. 304 when coupled with 416 Stainless Steel 1

[Dan B.]

I was looking for an appropriate galling resistance stress for a slow moving part I'm designing. You can think of it as a hinge. I found the article linked below which seemed very helpful. Table XI on page 24 shows various galling resistances, including my wear couple 303 vs. 416 Stainless Steel.
I have 2 problems with what I found though.

1. The units of the table are stated to be 10^6 psi. I'm virtually certain this is a typo as all the other tables (such as table XII) have unis of ksi or 10^3psi. And the max value for both is 50+ indicating their equipment only goes to 50ksi. So I think that problem is answered.

2. The 303 vs 416 SS galling resistance is listed as 9 ksi, while the 304 vs. 416 SS galling resistance is listed as 24 ksi. This is completely counter intuitive, as dozens of sources list 303 as having superior galling resistance to 304 due to the sulfur in the 303. Anyone know if there's something special about 416 that would make it perform better on 304? Or could this be a mistake too?
Thank you.

https://www.nickelinstitute.org/~/M...lingCharacteristicsofStainlessSteel_9006_.pdf

 

[EdStainless]

There may be lots of typos in these older papers.
Can you find the original paper
Schumacher, W. J., ''Wear and Galling Can Knock Out Equipment,"
Chemical Engineering,May 9, 1977, pp. 155-160

Many of these tests are done using less-than-stadard methods, and method is everything.
And in this case the 416 samples were Q&T, as opposed to annealed in some of the other tables.
While 303 and 416 tend to have better galling resistance due to inclusions they also have much higher wear rates, at some point this becomes negative.
And both 303 and 416 have poor corrosion resistance, 416 is not very stainless, so test environment could be an issue.
If you want galling resistance look at mating the Nitronic alloys (30 & 60) either with themselves or with hardened 410/416.
There is good data in old Nitronic 30 and 60 brochures. I have copies.


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P.E. Metallurgy, Plymouth Tube

 

[Dan B.]

Thanks for the response. I didn't find that Schumacher paper online. I'll try a library. I was thinking of Nitronic 60, I've used it a lot in past jobs, but my current manufacturing facility does not keep that in stock, so I'd have to add the stock to our inventory. We'll probably try 304 first since it has the acceptable corrosion resistance and test to see if it galls. The bearing stress is only 1500 psi so it should be OK I think.

 

[monkeydog]

According to the ASM Handbook (Vol 18) the threshold galling stress for 304 annealed is 8 KSI and for 304 Cold Drawn is 2.5 KSI.

 

[EdStainless]

MD, When mated to what? Itself?
My experience is that when mated to something over RC40, starting with cold worked 304 (RC20-25) significantly reduced wear and galling.


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P.E. Metallurgy, Plymouth Tube

 

[monkeydog]

Ed that was self mated.

304 (77 HRB) to 410 was 2 KSI
304 (77 HRB) to 416 was 24 KSI
304 (77 HRB) to 440C was 3 KSI
304 (77 HRB) to 303 was 2 KSI
304 (77 HRB) to 316 was 2 KSI
304 (77 HRB) to S17400 was 2 KSI
304 (77 HRB) to S24100 was 30 KSI
304 (77 HRB) to S21800 was 50 KSI

Lots of info in ASM Handbook.

Yes, similar to my experience was to try to achieve a large delta between hardness for the mating materials.

 

[EdStainless]

Those don't look right, but the hardness of the second alloy matters also.
For any two annealed SS on each other (or self mated the values of a 'few ksi' sound right.
Nitronic on a hard alloy (440 or a PH) are easily over 50ksi.

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P.E. Metallurgy, Plymouth Tube

 

[israelkk]

Just to mention that all those values are in "perfect" lab tests. However, in real life like in threads, shafts etc., even the smallest burr or imperfect bump on the surface will be a starting point for galling.

 

[rconner]

(...as will any sand or dirt?)