17-4Ph and contact with food
17-4Ph and contact with food
(OP)
I am working with a customer that wishes to change a shaft in food processing equipment to 17-4. But according to NSF guidelines, the material needs have chrome limits above 16%. Within these guidelines and the material properties he wishes to have (there is impact concerns), 440 A, B or C are his only choices (He also wants a readily available material). But there will be problems with corrosion. Part of the shaft will have some contact with a food slury.
Does anybody have any information or links to articles that talk about 17-4 in the food industry? I need to obtain information on the use of this grades in the food industry to try to get this grade qualified.
Thanks,
Bob
Does anybody have any information or links to articles that talk about 17-4 in the food industry? I need to obtain information on the use of this grades in the food industry to try to get this grade qualified.
Thanks,
Bob





RE: 17-4Ph and contact with food
www.stainless-steel-plate.com/17-4PH-spec.html
What is the food slury and temperature?
RE: 17-4Ph and contact with food
Thanks for the response.
Bob
RE: 17-4Ph and contact with food
Just curious. What is the reason the customer wants to change shaft material (fatigue failures?)
What was the original shaft material?
If you are dealing with an agency like the National Sanitation Foundation that certifies products, you probably will have to have 3rd party testing to qualify this material especially with the 16% minimum chromium requirement.
Have you considered a duplex stainless steel alloy (2205) in lieu of 17-4 PH?
RE: 17-4Ph and contact with food
Bob
RE: 17-4Ph and contact with food
We've been using lots of 17-7 and I havent seen a cert yet with Cr<16%, I would guess that 17-4 would be similar.
nick
RE: 17-4Ph and contact with food
The Cr content of 17-4 is 15-17.5.
RE: 17-4Ph and contact with food
BobUXL how about using 17-7 the strength should be high enough, the cost would be higher, and the Cr range is 16.0-18.0
nick
RE: 17-4Ph and contact with food
One can always use 301 in the cold worked condition. This is really cheap compared to 17-4PH or 450 or 2205. For a shaft this can be done with cold finished bar.
RE: 17-4Ph and contact with food
Table 1 from ASTM A 693 gives the minimum Cr content as 15.00%. This is a sheet spec, and I didn't bother to look up the bar spec.
BobUXL,
mcguire's suggestion of Type 301 seems like a favorable option. I would just add that Type 302 is more prevalent in North America for round products, whereas Type 301 is more common in flat products.
RE: 17-4Ph and contact with food
I'll yield since I don't have a current set of specs. I don't think that alters requesting 16.0% minimum, however.
301, 302, 303, or 304 would work equally well. Even 316, if there were a benefit from higher corrosion resistance, would work.
Cold-worked austenitics are a very under-utilized alloy system.
RE: 17-4Ph and contact with food
I agree with you and TVP that a cold-worked austenitic stainless steel could be suitable. I would like to comment on your under-utilization comment: who does the cold working? Can I get the bar in the length and diameter I need, and with the requisite delivery time from a mill? Do I work with a "converter" who can provide smaller quantities with specialized requirements? Who are good converters?
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: 17-4Ph and contact with food
I am much more experienced in flat rolled than in bar products...it's a whole different set of suppliers. I would think a converter would be a better bet than a mill, but I can't recommend anyone specifically.
In carbon steel it's always done by converters in cold finished bar. Any cold finished bar producer could do stainless as well as carbon steel.
Try calling Ulbrich, Allegheny, Cartech or Ugine. At the latter a guy named BobDrab at 800-523-3321 might be able to help.
RE: 17-4Ph and contact with food
Thanks for the reply. Now that you mention them, Ulbrich is a really good choice.
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: 17-4Ph and contact with food
What percentage reduction is typical and for example what are the UTS and YS for 302 worked this amount.
Jesus is THE life,
Leonard
RE: 17-4Ph and contact with food
All the suggestions and comments were good and very valid. However, not many of these suggestions are in anyone's standard inventory. With an austenitic, you have to order a cold worked material which no one really stocks, especially these days. 17-7 is the same. Not really mych call so there is very little inventory if any around. And for a 630 with a special Cr level, it can be done, but it is not standard. Plus, the customer is not using enough for a heat lot quanity of material.
The customer is already complaining about an alloy that is hard to get. And I am trying to establish whether a standard 630 has been used for food where is was OK'd by NSF.
Any links or documentation on this would be very helpful. I would like to get my ducks in a row to try, if necessary, to get the alloy approved.
Thanks,
Bob
RE: 17-4Ph and contact with food
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RE: 17-4Ph and contact with food
Why don't you get a distributor to stock your preferred item for you? They will simply go back to the mill and lean on them to make the item a standard. There's no reason a mill wouldn't logically make their 17-4 to a 16.0% minimum.
Or the size 301 you need. This would help everyone keep their customer.
Using a commonly available item has its disadvantage if anyone can obtain it. Wouldn't you want this customer dependent on you?