Princes Risborough-based Sumitomo Electric Hardmetal Ltd (www.sumitomotool.com) has introduced its T1000A and T1500A grades of uncoated cermet inserts as a cost-effective alternative to more conventional and costly coated cermet inserts when performing small-batch turning operations.

The uncoated Sumitomo T1000A (P10) cermet grade, which incorporates a dual structure for wear resistance and toughness, is designed for applications such as fine-finish profiling and continuous high-speed cutting of cast iron, soft materials, ferrous powdered metal, high-carbon steel and alloy steels.

T1000A is said to offer high resistance to built-up edge, even when cutting softer materials or ferrous powder metal.

It incorporates a composite ‘hard phase’ that uses a dual mix of strong but brittle ceramic particles in a soft but ductile metal matrix to enhance its toughness. According to Sumitomo, cutting speeds up to 400m/min are achievable.

Meanwhile, T1500A (P20) incorporates a series of 3-D chip-breaker designs that are said to maintain a high order of resistance to insert fracture and cracking when performing interrupted cutting cycles. A core and outer layer combine to enhance hardness and toughness for increased wear resistance and the suppression of cracking.
Typical cutting speeds are up to 300m/min.

In recent trials involving multi-diameter profiling on 34CrMo4 steel gear shafts, a T1500A DNMG insert allowed tool life to be extended from 800 parts per cutting edge with a competitor insert to 1,000 parts.

The operation was run with coolant using a cutting speed of 140m/min, a feed rate of 0.15mm/rev and a 0.25mm depth of cut.

Similarly, when finish-turning a multi-diameter 42CrMo4 shaft, Sumitomo says that a T1000A DNMG cermet insert increased the tool life from four to 10 pieces per corner. The machine was run with coolant at 180m/min, with a feed rate of 0.25mm/rev and a 0.4mm depth of cut.