Following the introduction of its latest-generation GC4330 and GC4340 steel-milling grades in 2018, cutting-tool and tooling-systems specialist Sandvik Coromant has extended the range of application for these advanced insert grades.

For instance, they are now available for use with the CoroMill 300 round-insert face and profile mill, the CoroMill 245 multi-purpose face-milling cutter, and the CoroMill QD cutter, which is optimised for deep and narrow grooving and parting off (www.sandvik.coromant.com).

GC4330 and GC4340, which feature a specially developed substrate, the Sandvik-developed Inveio coating and enhanced post-treatment technology, allow users to benefit from substantially increased tool life and process security.

Karl Emil Holmström, global product application manager at Sandvik Coromant, says the extension of these grades to more milling applications brings their advantages to even more machine shops looking to optimise the milling of steel workpieces.

He said: “GC4330 and GC4340 have been purpose-designed to overcome certain issues when machining steel components.

“For instance, some hard and abrasive steels can promote wear along the insert’s flank face, particularly at elevated speeds and longer times in cut, while machining in unstable conditions — as a result of compromised fixturing or long overhangs — increases the risk of chipped inserts.

"A further risk is thermal fluctuation during machining, which can lead to crack formation and sudden breakages, especially in wet conditions.

“Among the many design attributes of GC4330 and GC4340 is the optimised Inveio coating; this features uni-directional crystal orientation in the alumina coating layer, giving the inserts a new level of wear-resistance and tool life.

"Furthermore, the substrate of the grades gives highly controlled grain-size distribution for more-reliable and predictable insert behaviour.” 

GC4330 is a medium-hard grade for roughing to semi-finish face milling, while the tough GC4340 grade is preferred for rough shoulder milling and groove milling.

Both grades are now extended to the previously mentioned CoroMill 245 and CoroMill 300, as well as the CoroMill 360 heavy-duty face mill, CoroMill 419 high-feed mill, and LPMH-PM plunge-cutter inserts.

In addition, GC4330 is available for the CoroMill 365 high-security face mill, while GC4340 can be applied to the CoroMill 216 ball-nose end mill, CoroMill 415 small-diameter high-feed face mill, and the CoroMill QD cutter.

Sandvik says this list adds to the availability of both grades for CoroMill 390 and Coro Mill 490 shoulder mills, CoroMill 345 face mills, CoroMill 210 high-feed cutters, Coro Mill 200 profile mills and CoroMill 331 for grooving and parting off.