Thanks to everyone for your insights. Even though there is a lot of retained austenite, we still reach hardnesses over 60 HRC. This product is given a deep freeze, but there seems to be little visual effect on the structure. We cannot freeze in our own facility, so the lag between hardening...
If a conveyor furnace was used, it is possible for individual parts to "hangup" as the fall from the conveyor into the quench. They slow cool and then eventually "unhang" and drop in with other good parts. The hanging points come from poor furnace design, warped furnace parts that form a...
I agree with everything said so far. One other problem can be a contamination of the coolant itself (hydraulic fluids from the turning machines, lubrication oils, etc.) Look closely for leaks surrounding the turning equipment. Finally, we have also found it worthwhile to clean after machining...
We carburize small parts (rollers for bearings) in a rotary batch furnace using straight natural gas as the carbon source. We oil quench directly from the 1775F carburizing temperature. We then reheat to 1525F and drop quench in mineral oil. Tempering is performed at 360F. The attached...
