FEATURE ADVANCED MATERIALS & PROCESSES | SEPTEMBER 2024 60 series of hypoid ring gears with a 7.9-in. outside diameter. The requirements were to carburize and quench the gears to obtain an effective case depth of 0.032-in. at 550 HV and tempered at 356°F. Results are listed in Table 2. In example 2, the 4D HPGQ process was completed on a ring gear with internal teeth to compare distortion between pre and post heat treatment conditions. Ring gear dimensions included a 6.3-in. outside diameter. In example 3, the 4D HPGQ process was further improved on and tests were conducted on a coupling gear made from 8620 with a tooth model greater than 3. The distortion was compared between pre and post heat treatment conditions. The coupling gear’s dimensions included a 6.0-in. outside diameter. Associated dimensions measured include radial runout, axial runout, total pitch deviation, total profile deviation, and total helix deviation. In this trial, it shows that 4D HPGQ can maintain a 12 or higher AGMA Gear class quality rating, which is on the same level as press quenching. In general, the 4D HPGQ process proved that it could produce significantly improved distortion results from the hardening process in comparison to its pre heat treatment features. Comparatively speaking, the 4D HPGQ process can provide five times the improvement in distortion to that of batch oil quenching. When distortion is reduced, it flows downstream to the subsequent machining operations. Whereas machining and grinding steps can be reduced and/or even eliminated altogether. CONCLUSION Costs of post heat treatment material removal are significant to the overall cost of a finished component, from costly machines, special tooling, and skilled labor. It has been estimated that in the 1990s the automotive industry alone spent ~22.4 billion USD[2] to correct distortion in hardened components. 4D HPGQ is a new process that gives the end user a tool to reduce distortion of quenched components, and also fully optimize the quench process due to the system’s flexibility and customization. In addition to the distortion benefits, the system is environmentally friendly, and safe to operate. When 4D HPGQ is implemented in a machining work cell, it can eliminate the need for costly fixturing and material handling expenses associated with batch and press quenching platforms. ~HTPro Acknowledgments Research and publications were supported by the National Centre for Research and Development as part of project no. POIR.04.01.04-00-0087/15 entitled: “Equipment for high performance and precise heat treatment with a quenching deformation reduction system for direct application in downstream production chains of mechanical gearing and bearings.” For more information: Tom Hart, product manager, vacuum furnaces, Seco/Vacuum, 18282 Technology Dr., Suite 202, Meadville, PA 16335, 814.332.8549, tom.hart@ secovacusa.com. References 1. C.E. Bates, G.E. Totten, and R.L. Brennan, Quenching of Steel, ASM Handbook, Volume 4, Heat Treating, ASM International, p 67-120, 1991. 2. Bremen, Economic Consequences of Distortion, IWT (Institut fÜr Werkstofftechnik), Germany, 1995. 12 TABLE 2 — 4D HPGQ CHAMBER, ADJUSTABLE FEATURES Feature Deviation above mean Flatness 5 – 25 µm Axial runout 20 – 65 µm Ovality 10 – 38 µm Fig. 5 — 4D HPGQ live images from video. Interested in advertising with the ASM Heat Treating Society? Contact Kelly “KJ” Johanns at kj.johanns@asminternational.org.
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