Chrome/Nickel coating to increase hardness
Chrome/Nickel coating to increase hardness
(OP)
We are running a part on two rails (.75 diam) using steel linear motion ball bearings (open). They have to be steel because the area where they work is subjected to high temperature. The thing is the bearings are ruining my rails because the bearing balls (60/70 Rockwell) are harder than the rail (40 Rockwell). We really don’t want to change the rail material, and the .75 ball bearings only come with 4 tracks of balls (…from what I found). We are trying plating the rails with electroless nickel and hard chrome to increase the hardness. Does anyone have any experience on this and can give me any comments? Any alternative process to increase hardness without changing the material?
The tube is 17-4PH heat treated to H900.
Thanks
The tube is 17-4PH heat treated to H900.
Thanks





RE: Chrome/Nickel coating to increase hardness
GO here for info on 17-4(7) heat/mechanical treatments:
http://www.aksteel.com/pdf/markets_products/stainless/precipitation/17-4_PH_Data_Bulletin.pdf
Also there has been lots of discussion in the last few months about a process called Kolsterizing. (IIRC thats the name) I think that its a Salt bath process that uses nitrogen to produce a very hard case on stainless steels. It allows the stainless to keep its corrosion resistance.
go here:
Thread330-49696
good luck!
nick
RE: Chrome/Nickel coating to increase hardness
RE: Chrome/Nickel coating to increase hardness
RE: Chrome/Nickel coating to increase hardness
We used .011" for Cr and .007" for the NI for any type load.
We had good luck with 17/4 liquid nitrided with the Kolene QPQ process.
What temperature do the rails and bearings see?
"Case 60" will take a pretty good temperature, much higher than the rollers
RE: Chrome/Nickel coating to increase hardness
QPQ process
www.kolene.com
Shafting
Both make a 440C linear support shaft.
http://www.nookindustries.com/linear/LinearShafting.cfm
http://www.thomsonind.com/Sections/Products/products_main.asp?PC=2000000&GI=1
RE: Chrome/Nickel coating to increase hardness
We are plating the rails with hard chrome this week and probably do some wear tests. I’ll keep you posted with the results.
Discussing with the plating company a new question came up: If we use a hard dense chrome, what is the effect of welding an attachment direct to the chrome, or should we locally remove the chrome from the area to be welded. We have some advice that you can weld direct to/through the chrome, but if we are joining 17-4PH to a 316 Cres support structure should we remove the chrome?
Again, thank you very much.
RE: Chrome/Nickel coating to increase hardness
RE: Chrome/Nickel coating to increase hardness
RE: Chrome/Nickel coating to increase hardness
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be slowed down.
RE: Chrome/Nickel coating to increase hardness
RE: Chrome/Nickel coating to increase hardness
Thanks to everyone for your help.
Best regards.
RE: Chrome/Nickel coating to increase hardness
While waiting for the results, I suspect you are correct. One of the first failure anaylses I was involved with was because of a thick hard Cr plate instead of the required thin (0.001") plate. Sorta like loading a piece of glass that's sitting on a block of clay.
RE: Chrome/Nickel coating to increase hardness
RE: Chrome/Nickel coating to increase hardness