AC4000K Turning Grades Provide Double the Wear Resistance

Sumitomo Electric Carbide Inc.’s AC4010K and AC4015K series turning grades for cast iron feature recently developed technologies that are said to result in a longer and stable tool life. Consisting of a smooth cutting edge treatment (Rz 0.15 – 0.07 micron), the AC4000K series’ use of high adhesion technology is designed to improve peeling resistance.

In addition, crystal orientation-controlled alumina layer technology, similar to that used in the company’s Absotech coatings, provides double the crater wear resistance for high-speed machining compared with conventional products. A hardened C-rich fine TiCN coating layer provides double the flank wear resistance during cast-iron machining. The residual stress control technology of the AC4000K series further contributes to wear resistance.

Recommended for high speed and high efficiency cutting of gray cast iron, the extra-thick coating of the AC4010K grade allows for ultra-high-speed machining with a Vc of up to 2,300 sfm. Its special surface treatment is said to provide more than twice the compressive stress and two times the chipping resistance compared with conventional products.

Increasing the mechanical strength and adhesion strength of the coated films was essential to improving the chip resistance. This was done by suppressing crack propagation in coated film, Improving the strength by controlling the growth orientation of Al2O3 crystallite and improving adhesion strength of coated film.

The range of applications and parts for the AC4010K grade includes cast-iron brake discs, flywheels, differential cases, gear cases, cam shafts, as well as standard gear parts. The chipbreaker selection includes the EGU for low rigidity setups, the ENZ for general finishing, the EGZ for extra cutting edge strength and the EME for strong and sharp high-feed roughing, as well as heavy machining. The company also offers a variety of flat-top no-chipbreaker geometries for various roughing and heavy machining applications. Sumitomo also offers this item in the EGUW wiper geometry for heavy feed applications.

While gray cast iron is known for its chemical abrasiveness, ductile and nodular iron machines are different. Recommended for the general purpose cutting of ductile cast iron, the high-adhesion and high-strength coating of the AC4015K grade provides long and stable tool life when compared with conventional grades. AC4015K is also capable of high-speed machining, even in ductile or nodular iron up to 1,500 sfm.

“We’ve seen a profound improvement not just against the conventional grades, but directly against the competition as well,” says Daniel Jacobson, planning supervisor at Sumitomo Electric Carbide. “The crystal orientation control and the harder TiCN coating have proven to be invaluable weapons in industries where cast iron is used heavily. Running the AC4000K series against conventional grades has seen at least a 33 percent increase in tool life in gray cast irons and has shown a significant improvement in ductile irons. For those auto parts that are still being made out of some varieties of ductile iron, because of the sheer volume inherent in these parts, a 5- to 10-percent increase in tool life or decrease in cycle time can mean a lot of savings for our customers; thousands, tens of thousands or even hundreds of thousands of dollars on a few operations.”