Screwman,
This is what we are now leaning towards...... The reason we didn't really want to do that is from a maintenance stand point...... but give and take I guess.
I agree with you tbuelna, if it was my product it would not be my choice.......but........
And there biggest reason for the change was actually the HRC. They had a lot of buggered screws in assembly and wanted something in the low 50's.
Thanks,
EdStainless and tbuelna,
Thanks, you have been a wealth of info and it is greatly appreciated!
And this is actually for the cutlery industry believe it or not, so strength and corrosion are the big factors for my customer.
Again, Thanks all :)
Cloa,
Thank you
tbuelna,
Thanks that helps...... It does really look like PH13-8Mo is a very good alternative to what I am looking for. I will do some samples in that and test them.
ScrewMan1,
Excuse my ignorance but what is ESCC and SCC?
EdStainless,
Thanks for the info!
Rconner,
Carbon fiber [ am curious why that matters?]
BiPolarMonent,
Yes it's intended to be a bushing that captures something and no, only 416 & 440C so far. And at this exact moment while we...
Israelkk,
Yes, we get a colored heat tint. We didn't passivate it only ran them through a vibe to even out the color.
EdStainless,
Yes, we are looking at better grades now. (416 is just so easy to machine)
TVP, Thanks I will look into that, as I like the machining rates of 416.
EdStainless...
Hi tbuelna,
Is it just something about a fastener that makes 440C a poor choice? I only ask because we have made dowel pins from it with good results and also other parts out of plate in the 58-60HRC range with good results also. And it also seems to be used a lot in cutlery. Is it just the...
Hey Kenat,
No not much. It is threaded 8-32. We could possibly get a very small undercut in there. It has been a very weird case. Most, 95%, have broke in connection with the slot on top but a few have just broke off the threaded portion/stud. We have done a pull test on a select few with no...
Thanks Terry,
Yes, we are machining the part 100% before heat treat. They are pretty small so are being quenched in air. I will look at those two materials but at max HRC, IIRC, is high 40's and may not be hard enough for my customers requirements. We use to make them out of 416SS at 40 HRC...
I have added a pic to show just what is happening. http://files.engineering.com/getfile.aspx?folder=b6d720df-a9e1-44d1-b06a-0d5b6e9f2c14&file=2013-12-02_15.03.31.jpg
Hi All,
I am having a major problem with a 440C fastener heat treated to 53-55HRC. It does have a sharp corner at the bottom of the slot so not sure if this is causing a stress riser or if I am just overlooking something but I have about a 10% fail rate. When put under lite torque (just by...
Well I just want to say thanks to everyone for the help it is most appreciated. We did fix the problem with the material change so all is good. Again thanks. [thumbsup]
Travis,
I would just say you are going to get what you pay for. Not sure what kind of tolerance you would need to hold on your parts but anything in the 10k and under range is not going to be tight.
Travis,
Well I tried the MolyKote. It did dramatically reduce the shaving/peeling effect and made the pin go in much easier but the pin also came out almost as easy. So I will have the 440 tomorrow and we will see what that does hopefully it is the hardness difference that is making this so difficult...
I will give it a try, the 30 deg, and yes I think the harder material will help the most. I will be ordering some 440 tomorrow regardless of the lube outcome. And thanks again for all your help it's extremely nice to have a place like this for idea's.
Travis,
mfgenggear, Yeah I am afraid that is going to be the solution. And I also think I will skip the 420 and go with 440C then I can get within a couple of points of HRC of the part.
Thanks again, I will let you know if the lube works or not.
Travis,
hydtools, 90 deg.
israelkk, I don't see it as galling. It is peeling the material right off like peeling a potato. Unfortunately I can't use a step hole/pin as I need this pin sticking out both sides of the part at it's proper size. After pressing the pin in I can press it back out with hand...
TVP, I am using the acetone with the dry ice for a poor mans liquid nitrogen. My Nitrogen container won't be in for another week. I have some of the molykote coming in tomorrow.
hydtools, It is .008/.01 on the hole and about .02 on the pin.
Screwman1, Yeah it is extreme the holes are all right...
