thanks guys, I'm waiting to see what maintenance has to say regarding the machine ground.
metengr - can you recommend a couple labs who are knowledgeable in this area? NADCAP preferred but not required.
I am looking for possible explanations and reference material related to pits found in steel parts after turn operation. Customer keeps rejecting as corrosion, but they are being found as they come off the machine.
Material is forged steel, German grade WL 1.6722, vac.arc remelted, quenched...
I agree with moving to VIM/VAR grade.
As for vacuum carburized - is it getting gas quenched? Or getting oil quench, followed by deep freeze and temper?(preferred)
Pyrowear53 is carburizing grade steel that will have better toughness and may be suitable alternate.
CPM10V gear blanks were left in 2030 deg F. vacuum furnace for 11 hours due to T/C malfunction.
Vendor is looking for a way to determine effect of this on integrity of parts and what testing, such as tensile or charpy, may indicate if parts can be used.
Thanks
I am considering making support for large gear during carburize cycle. Fixture is to be re-usable also. We normally used low carbon steel with decent success.
My question is whether there is any benefit to using cast iron instead, either by cost savings or durability.
Cylce will be 1700 F for...
1. Citric acid will also work well to remove white layer.
2. If parts were not core hardened prior to machining and nitride, that may have contributed to the distortion.
I could not find either of those material specifications on GE's current specification index( Oct. '07). They must have been cancelled or superceded at some point, but there is no reference to them at all.
Mike
metengr - NDT house did use WFMT per ASTM E1444, but these were made from CF bar, not forgings. The thing that drives me nuts about some vendors, is that they write up the reject and move on, no further exam, no call to discuss, nothing
TVP- what is a carbide stringer?
Thank you both for...
we make some pump gears from aircraft quality 52100 steel(not vac melted). Outside NDT house rejected 15 of 58 pcs for inclusions over spec. limit of .125"
When we mag. particle inspected in-house, the indications are long thin lines running length of part, almost perfectly straight to axis...
We have magnesium castings, alloy AZ91C-T6. Engineering wants to heat these prior to assembly/insertion of steel bearing liner. My question is how to determine maximum temperature these can be heated to. I thought any temperature under the last tempering temp. would be OK.
thanks
I would love some confirmation if I am on right track or way off here. We make a landing gear axle out of 4340 steel that always moves a bit at heat treat-we roll quench after heating to 1500 for 2 hrs.70% of length is solid 2" diameter, ends are tapered and hollowed out, min wall thickness...
More questions than answers: Is there any concern for vibration dampening that cast iron provides?
Can you use a S-grade or O-1 tool steel?
Regardless of material, machining from bar instead of plate would give better strength from grain flow.
are you heat treating the blanks prior to machining? A normalize, quench, and temper to 28-34 HRC will take out a lot of your movement at carburize, as well as improve machinablity. I agree with mewhg that the heat treater may not care about distortion - see if he can control pre-heats and...
