Gas Vs. Liquid Quenching- A Direct Comparison

"Gas vs. Liquid Quenching - A Direct Comparison" By: Robert Hill President Solar Atmospheres of Western PA It is a well-known fact within the heat treating community that high pressure gas quenching yields far less distortion than liquid (salt, water, polymer, and oil) quenching. Metallurgical science regarding cooling rates and hardenability has neglected HPGQ technology, until now. This paper will introduce revolutionary information for the metallurgical world – side by side comparisons of water vs. gas sprayed Jominy End Quench Tests for hardenability. The high velocity gas that will be sprayed at the end of the 1" OD x 4" long specimens will be typical of the gas velocities that parts would encounter in a newly designed 20 bar furnace. Hardness results and microstructure results will be directly compared on various alloys. Additionally, a new universal load size and test block to determine cooling rates will be introduced based on the North American Die Cast Association (NADCA) specification. This new information will be proposed as a standard for all heat treating equipment- whenever there is a desire to compare critical cooling rates.