[heattreater]

Can anyone share their experience on implementing new technology to improve the accuracy of their carbon potential measurement in a batch atmosphere furnace (i.e. IR, 3 gas, etc.). Has your process results (effective case depth) been more predictable and repeatable?
Thanks,
heattreater

[DrOrpheus]

Yes, an infrared and 3 gas is a very important necessity to ensure your producing quality atmosphere as well as monitoring the output of the furnace. I'd say you should have at least one seperate means of measuring. CO2 will tell you alot, but a 3 gas will tell you a bit more. As far as my experience with it improving our quality or case depth, I don't know, we have a pretty good track record of repeatability with the people we have that keep up with the stuff. We've always had an infrared unit that we used to monitor the furnaces with to verify the carbon sensors were running right. Recently, we started using a 3 gas, and it has helped us keep a nice log of what our generator and each furnace is doing on a weekly basis. If you're not using at least an infrared to sample your furnace/generator gas, then you're running in the dark. They help you identify that there's something wrong with your atmosphere. Such as leaks in the furnaces, un burnt natural gas comin out of your generator, etc. I say keeping up on your endo quality and maintaining repeatable gas mixture using a 3 gas will help keep things smooth. Having said that, there's nothing more frustrating than having conflicting numbers from each analyzer. Keeping it properly calibrated is obviously important. I'd look to Super Systems for their input,product, and support. I know having the 3 gas has helped us identify problems with furnaces and made you aware right away rather than finding out after it's too late.

[JCP]

I may be very old school here, but I remain convinced that verifying carbon potential readings in atmosphere furnace is best accomplished by shim analysis with a Leco carbon analyzer. 3 gas/ IR/ etc all work well, but are maintenace intensive. They also infer carbon potential based on the ratio of CO/CO2/H2. A properly run shim test gives you an unquestionable reading of what your actual carbon content in the furnace is. I've been is some very modern aircraft carburizing shops in the past few years, that still use Leco's on a daily basis.

[DrOrpheus]

I agree, shims do wonders, but with a properly maintained IR or 3 gas, you see what's happening in real time and have an oppurtunity to prevent bad stuff from happening rather than find out after the fact. Plus, like I said earlier, it helps you keep your endo generator in check. We do run shims with our longer carburize runs to ensure things are working properly and have a nearby lab "zap" it with their machine, but we don't have easy access to do that all day and night multiple times, we verify with the IR and 3 gas and keep them properly calibrated.