Thank you all for your comments.
1) Based on this input, I am planning to revisit the machining and try some speed/feed experiments to see how it correlates to the problem. We had been hoping for a “gold” nugget, but I am now thinking that it is simply that just too much internal stress has...
i will do- it another frog to kiss- i hope it turns into a princess!
i will be out of pocket for several days, so no more replys today.
many thanks to those who have posted today and i will follow up in a few days.
hopefully i can one day give someone else some help.
Thank you for ure reply- that very well may be part of the problem as we are using high speed cnc machines to drill, or rather almost punch the holes into the parts. The problem did start soon after we switched methods and we have made changes as you suggested to insure the tools are changed...
swall- thanks for ure reply
1) Not sure about how the posting of pictures works- so- if you look at an adjustable wrench on end so that the movable jaw is on top, you will see 2 holes and a slot which the jaw moves in. the crack is in the thin cross section between the large hole that the...
metengr- thanks for your interest and help-
I am thinking that maybe we are getting hydrogen sulfide from anaerobic bacteria growing in the system so I am interested in what concentration of hydrogen sulfide in the cleaner baths and rinses should we consider treatment with something like carbon...
Thank you metengr for your reply. i am very much interested in how much hydrogen sulfide concentration in a cleaner or rinse might lead to stress related cracking or other HE problems as this is something new as opposed to a long term issue.
regards,
roy
Cory, thank you for your answer.
1)Yes- we wish to eliminate the stress relieve operation due to cost.
2) Our test indicate that they break right after nickel plating and prior to chrome plating. I was thinking that the HE in plating was the straw that broke the camel’s back. Where they break...
We manufacture adjustable wrenches from 5151 steel. They handles are hardened to Rc 40-50. We have recently begun experiencing some cracking during nickel-chrome plating. (1-2% failure rate) The cracking does not occur if we stress relieve the parts prior to plating using a 600-degree stress...
