To control chips when turning superalloys, such as Inconel 618 and 718, Tungaloy America Inc., Wood Dale, Ill., recently introduced the AH905-grade insert with HMM chipbreaker. The ribbed chipbreaker diminishes heat in the gullet to keep it from penetrating the insert, according to Brian Sawicki, the toolmaker’s senior manager of engineering and products. Tungaloy reports that the chipbreaker sits flush against the shim seat to improve stability and extend tool life, has a sharp T-land to reduce cutting force and the rake surface geometry minimizes heat transferred from chips. “The chipbreaker produces less surface contact with the chip,” Sawicki added.

He noted that the insert grade, which is the company’s hardest for turning high-temperature alloys, is designed for continuous cuts with a DOC from 0.020 " to 0.125 " per workpiece side and a 0.004- to 0.012-ipr feed rate.