303 Vs 304L

[thermoD]

in our application, 304L component is press-fitted to 303 component (as insert and sleeve). Recently, our supplier unintentially used 303 for both components, huge amount of products have been made, business wants to assess the impact before scrap.

my concern would be steel galling? but can't tell whether it will be worse or the same with supplier's mistake.

any guidence??
notes:
Corrosion is not issue here
304L component requires Rmax 8 surface finish (any impact on surface finish?)
Our supplier has performed testing and dimensional check and all positive, but should I trust them?

 

[btrueblood]

304 was on the o.d.?

303 now on the o.d.?

An issue is the possible, if not likely, presence of sulfide stringers in the 303, tending to reduce its fatigue capability. In a press-fit, you are preloading the metal in tension...so if there is any possibility of overcoming the preload, and inducing cyclic stresses on the o.d. part, you may see fatigue failures down the road.

Past that, the 303 is weaker, and you may see failures cropping up during the press fit operation. The nice thing is these will be fairly easy to screen out.

 

[tbuelna]

thermoD,

If galling is your only concern, then you're better off with 303 instead of 304L. The same alloy constituents (Se, S, P) that make 303 free machining also make it less prone to galling. But as btrueblood notes, 303 is also much more prone to fracture than 304L for this same reason. In fact, many industries such as aerospace usually prohibit the use of 303 entirely.

Check with your stress or M&P guys.

Regards,
Terry

 

[EdStainless]

You may have trouble reaching you finish with 303. The huge stringers in it will show if you polish.

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Plymouth Tube

 

[unclesyd]

There will be no difference in the tendency for 303/303 to gall than 303/304 to gall. The information in brochure shows that there is a possible wear problem when you have a self mated 303/303 rubbing together. The wear rate will depend on speed and load and lubrication, if used.

http://www.hpalloy.com/alloys/descriptions/NITRONIC60.html

 

[strider6]

have a look also at

http://www.bssa.org.uk/cms/File/SSAS5.60-Galling and Galling Resistance of Stainless Steels.pdf

http://www.corrosionist.com/Materials_Stainless_Steel_Properties.htm

s

Corrosion & Rust Prevention Control