Work material and the effectiveness of coated tools

Earlier studies have suggested through the use of wear maps, that significant benefits of coated tools (in terms of lower tool wear rates) may only be realized when the appropriate machining conditions (cutting speed and speed rate) are chosen. This paper investigates the effects of work material on the wear improvement of coated tools by comparing uncoated and titanium carbide (TiC)-coated cemented carbide tools when cutting two medium steel grades: AISI 1045; and AISI 4340. Wear maps constructed for these tool-work combinations show that the TiC coating is more effective when machining the softer plain carbon 1045 grade, decreasing tool wear rates by half an order of magnitude or more over a wide range of cutting conditions. More modest reductions are achieved with the harder 4340 alloy. Nonetheless, with both steel grades, the TiC coating still significantly expands the range of machining conditions under which acceptable levels of tool wear are obtained.