Blade-breakage-resisting surface coating cutting tool with excellent performance of hard coating layer

Abstract

The present invention provides a blade-breakage-resisting surface coating cutting tool with excellent performance of a hard coating layer. A Ti compound layer which at least comprises a TiCN layer is coated on the surface of a tool substrate as a lower layer (a). In the surface coating cutting tool in which an alpha Al2O3 layer is used as an upper layer (b), for the TiCN layer of the lower layer, when an included angle of a normal line of a surface [110] is formed by a field emission scanning electron microscope and is prepared to an inclination angle number distribution graph, the TiCN particles [110] of the inclination angle in the range of 0-10 DEG accounts for more than 50% of the whole particles. Additionally, for the alpha type Al2O3 layer of the upper layer, when the inclination angle which is formed by the normal line of a surface (0001) is measured and prepared to an inclination angle number distribution graph, the Al2O3 crystal particles with the inclination angle in 35-45 DEG accounts for more than 60% of the whole particles. Furthermore when observed in a surface which is vertical to the layer thickness direction, crystal particles of the Al2O3 (11-26) are coarse and large, and average crystal particle diameter of the crystal particles of the Al2O3 (11-26) is 2-5 times of the crystal particles except for the Al2O3 (11-26).

Description

technical field [0001] The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool), especially for various steel or cast iron, etc. The hard coating layer also exhibits excellent chipping resistance in long-term use when cutting the cutting material. Background technique [0002] In the past, it is generally known that the surface of a substrate composed of tungsten carbide (hereinafter referred to as WC)-based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN)-based cermet (hereinafter these are collectively referred to as a tool substrate) is generally known. A coated tool that is plated to form a hard coating layer consisting of the following (a) and (b), [0003] (a) The lower layer is composed of Ti carbide (hereinafter represented by TiC) layer, nitride (hereinafter also represented by TiN) layer, carbonitride (hereinafter represented by TiCN) layer, carbon oxide (hereinafter represented by TiCO) ...

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Problems solved by technology

[0018] The current situation is as follows: in recent years, the performance of cutting equipment has been significantly improved, and on the other hand, the demand for labor saving and energy saving in cutting processing, and further cost reduction has been strengthened. With this, cutting processing has gradually tended to increase in speed, but In the above-mentioned conventional coated tools 1 and 2, there is no problem when they are used for continuous cutting or interrupted cutting under normal conditions such as steel or cast iron, but they are especially used for high heat generation and impact and When an intermittent load acts on the blade under high-speed intermittent cutting conditions, the high-temperature strength and impact resistance of the hard coating layer are not sufficient. In addition, once the hard coating layer cracks due to impact, etc., the layer The internal stress in the steel promotes the development of cracks, and it is prone to chipping and defects. As a result, the service life is reached in a short period of time.

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