Recent content by mewhg

WKTaylor, I would think .001-.004" clearance would be perfectly acceptable. Should the bolt to hole clearance be eliminated? A core drill being is used for match drilling after the wing assembly is fit up?

Investment casting in my experience have a fair amount of subsurface defects (small voids, slag inclusions). If the part is highly loaded and in a critical application (aircraft, vehicle) forging is the better choice.

Thanks for all the replies........ The part is partially splined and about 3/4" diameter. The splines transmit some rotary motion but sometimes they are loaded longitudinally. Its the longitudional loading that is causing problems as the splines are not very long and they are fairly tall...

Thanks for the suggestion Terry. The problem with this part is that it is overloaded and needs a redesign. But because of how long this part has been in the field (mid 1960s) the geometry can't be changed because it has to still fit with the rest of the machines still in use. It's a bit of a...

We have legacy part traditionally made from 9310 AQ steel, vacuum carburized and shotpeened. It is highly loaded in a semi-shock mode and under low cycle fatigue (75k cycle expected lifespan). Failure (cracking) of the component has always been a problem way before 75 k is reached. Changing...

Yes, We do spot MP before heat treatment and 100% after heat treatment.

I have a pawl looking type of part that is made from either 8620 or 9310 steel. It is carburized to an RC50 of .015" and then cryo treated and tempered back to a hardness of about 90 R15N. After heat treat certain critical sections are shotpeened . The part is failing in fatigue. After about...

We are in need of a good hardness tester. It will need to do about 300 Rockwell C hits a day + the occasional R15N. We are looking at the NewAge Indentron. Cost is about $17k. Does anyone have any experience with this one or others? TIA

Thanks everyone for your replies

Any other suggestions?

We are in Pennsylvania.

I am in need of a good testing laboratory. The ones near us just do not have the experience or equipment necessary. The lab should be able to perform complete failure analysis with in house *SEM *Grain Size determination *Retained Austinite determination *experience with failures of...

I had a go at this last week. Ionic Technologies in SC did the nitriding and PVD coating. A very professional outfit. In testing the PVD/nitriding wore thru at one critical location after 20,000 cycles of the part. I think it was due to the lower hardness of the core 4130 not being able to...

Thanks TVP, I getting some samples that are Ion Nitrided .010" thk with an Aluminum Chromium Nitride coating. I will report back with how it goes.

We are having a problem with wear on a 1/8' thk 4130 sheet metal lever. Currently the lever is Q&T to 50 HRC. We are thinking about taking the existing levers and having them Ion Nitrided about 0.010" deep and then possibly PVD coating. I am aware that the 50 HRC lever would decrease in...