The company I work for has metallurgy/polymer labs in Texas, Louisiana and Singapore. Would anyone happen to know of a calibration company capable of handling calibrations in those parts of the world? The equipment is primarily metallurgical (tensile machines with mechanical/digital...
In general, what are the major factors that should be considered when trying to decide between different steel grades for the same application? For example, if I want to make a simple combination wrench and have to choose between 4047 and 5046 what should I base my decision on as it relates to...
JConnBMKR,
These go through several machining steps including soft vibe after forging. There is even an additional hard vibe step administered after heat treating to remove even more surface material.
Unfortunately though, I don't believe these processes really remove enough material to get...
Stanweld,
I will make that suggestion to the plant that they need to consider removing all scale remnants as well as any laps and seams. I think though that if this problem continues then the material supplier will have to be changed for sure.
brimstoner,
The plant informed me that they have...
Thanks again metengr,
Yes, I do agree the most important thing is to take preventative measures. Of course, it's always nice to be able to pinpoint the origin of such defects.
I've got a raw material auditing program established to try and catch these defects before they have a chance to reach...
I was just informed that the billet is received as hot rolled bar stock. Bars are then cut down to billet lengths using cold shearing. No other work is done to the billets prior to hot forging.
From this info, would it be much more possible that these defects are most likely rolled-in scale?
Thanks metengr,
I will try and find out what condition the billets were received in from the material supplier and if they were rolled by working prior to forging.
Just for the sake of comparison, I've attached some unrelated photos of a billet I was asked to examine recently and found what...
I have received a couple of wrenches that are showing the as-titled surface defects. These wrenches are in finished condition and were made from steel grade 4047. Steel and hardness results meet spec.
After microscopic examination, I found some defects that are outlined by a thin decarb...
A big thanks to all that posted.
Brimstoner,
Ok so the thin, dark etched layer beneath the surface is just related to the oxide (?) inclusions and not anything to do with decarb?
That brings up another point of confusion for me. I have seen and been advised that forge cracks or forge...
Thanks Redpicker. I always look forward to your responses.
That does make a solid case for forging lap. As decarb showing up during etching, maybe I don't understand something. I was under the impression that decarb layers would show up as lightly colored in contrast to surrounding areas...
Thanks Brimstoner.
1) I considered forging at first due to the corner being so heavily oxided and the appearance on the fracture surface. I thought that if it was a forging crack though that I would have been able to see a decarburized layer. My etching didn't show any sign of decarb at all...
I've received two Craftsman 1/2" drive teardrop ratchets in finished/plated condition that experienced premature failure during routine torque test. Both failed at the same site located at the fork.
Results so far:
1. Bulk hardness of 46-48 HRC meets spec (40-48 HRC)
2. Chemical composition...
