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Decarburization-Free and Soot-Free Batch-Annealing with Automated Atmosphere Control

LAB RESULTS Mounts of the AISI 1040 material annealed in the above cycle using the APEx process can be seen in figures 5a/5b. Although the excellent 100% spheroidization can be seen, APEx cannot take credit as this is a result of time-at-temperature and controlled cooling. The effect of APEx can be seen at the left edge of the material where a consistent carbide matrix extends all the way to the surface. These results were reported as an average 0.001” depth of partial decarburization, with 0.000” depth of total decarburization.
Figure 5a: Before Annealing Figure 5b: After APEx Annealing CONCLUSIONS A properly controlled nitrogen/propylene atmosphere can achieve repeatable results on subcritical annealing of ferrous wire and wire rod. The keys to success are: Lowering nitrogen flows to absolute minimum levels. Using additional higher flows of propylene to speed up cycle time (leading to cost savings in fuel, electricity, and nitrogen). Accurate and repeatable measurement/inference of decarburizing agents that occur at trace levels (O Controlling depth of partial decarburization to meet specific manufacturing requirements of wire users.
2 , H
2 O, and CO
2 ). Reducing/eliminating the air burnoff segment to introduce less oxidation and speed-up the APEx ramp time on subsequent cycles. Integration of the temperature control with the atmosphere control. Control of the critical ramp from 1100°F to soak (~1300°F) to prevent decarburization. Avoidance of carbon deposition by shutting off the propylene during soak after all major reactions are complete. The mark of a breakthrough technology is one that opens the door to many additional possibilities. Some of the additional benefits being considered/pursued: Applying APEx to continuous annealing processes that use a protective atmosphere.
Dr. Robert N. Blumenthal Christopher J. Messina Arno Muennich Chief Systems Engineer RAD-CON, Inc. Vice President, Technology RAD-CON, Inc. As Vice President of Technology at RAD-CON, Mr. Messina has been developing various innovations in the batch annealing process and specifically in the area of atmosphere control. He has worked in the heat-treating field in various engineering and developmental capacities since 1987. Mr. Messina holds a Bachelor of Science degree in Engineering Physics from John Carroll University (Cleveland, OH USA). Mr. Muennich currently heads RAD-CON’s control system development since assuming the Chief Systems Engineer position in 1996. Mr. Muennich has been in the industrial controls field since 1987. He holds a Bachelor of Science degree from the Electronic Technology Institute (Cleveland, OH USA). As both president and co-founder of Furnace Control Corporation and Advanced Atmosphere Corporation, Dr. Blumenthal developed zirconium oxide technology for controlling heat-treating atmospheres throughout the 1970s, 80s, and 90s. Dr. Blumenthal taught Materials Engineering for 32 years at Marquette University and was granted the title of Professor Emeritus upon retirement in 1996. Page 4 of 4