While chemistry and crystallographic control are probably among the last things that anyone would associate with machining cast iron or stainless steel, those two things are fundamental to the DurAtomic coating process developed by Seco Tools Inc. (www.secotools.com; Warren, MI—although the company has been known in the U.S. as Carboloy, it will fully transition to its parent company’s name by January 1, 2007. The company claims that the TP2500 grade developed with the process provides an improvement of 18% to 400% in tool life and 55% to 100% in productivity, and a 49% to 80% decrease in wear. TP2500, available in an array of geometeries, including positive and negative rake angles and as a wiper, is the first grade created with the chemical vapor deposition (CVD) process.
Essentially, the aforementioned crystallographic control is about alternating the crystal structure of the aluminum oxide (Al2O3) layer. The consequence is that there is a superior bonding of the coating as well as an improvement in mechanical wear. Kurt Nordlund, senior vp of Marketing for Seco Tools AB (Fagersta, Sweden), suggests that the resulting change is “almost as big as going from uncoated to coated tools.” In addition to the coating, TP2500 has a functionally graded substrate structure that contributes to edge toughness without a sacrifice of strength in the other areas of the insert.—GSV