Finishing

By its very nature, high-nickel, iron or cobalt alloy steels, including Monel, Inconel, Incoloy, Invar, Rene and Hasteloy, are some of the most difficult materials to machine. Because these superalloys are designed to deliver high strength at extremely high temperatures in components often found in “hot” sections of engines and turbines, the stresses and heat generated during machining are considerable.

For the May issue’s focus on abrasive machining, I’m writing a multiple-source article about honing. One of the sources is Lapmaster Wolters LLC.

In connection with my feature article on abrasive machining for the May issue, I spoke with Steve Kendjelic, senior applications engineer for Norton/Saint-Gobain Abrasives, Worchester, Mass., about power gear honing. The process is used for ultrafinishing generated gear teeth and is generally performed on a honing machine.

When mass finishing—finishing many parts simultaneously—in a vibratory finishing system, the tendency is to use ceramic or plastic preformed cutting media, said Steven Schneider, technical sales manager at surface finishing company Kramer Industries Inc., Piscataway, N.J. Ceramic tumbling media are made with abrasive filler, much like a grinding wheel. For plastic tumbling media, plastic is mixed with abrasive filler and cast to shape. Ceramic media use aluminum oxide as filler, and plastic media use quartz or silica for cleaner results.