Indexable Insert Coating for Wear Resistance and Adhesion
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Solution Overview
Problem
Current indexable inserts fail to simultaneously achieve high wear resistance and toughness, and often experience surface layer separation during high-speed cutting and machining of difficult-to-cut materials like gray iron.
Innovation Solution
The development of an indexable insert with a specific coating composition and structure, featuring a titanium boronitride or oxyboronitride underlayer and an alumina-containing outer layer, where the outer layer thickness is controlled to be thinner at the rake face side than at the flank face side, enhancing adhesion and preventing separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a layer containing alumina is used as the surface layer to prevent welding of the workpiece, then welding prevention is improved, but adhesion to the underlayer deteriorates causing surface layer separation
Solution Approach 1:
The second coating layer made of titanium boronitride or oxyboronitride acts as an intermediary layer between the alumina-containing first coating layer and the substrate. This intermediate layer improves adhesion between the alumina layer and the substrate, preventing surface layer separation while maintaining the welding prevention properties of the alumina layer.
Solution Approach 2:
The composite coating structure combines alumina (for welding prevention) with titanium boronitride (for adhesion). This material combination allows the system to simultaneously achieve both welding prevention and strong adhesion, resolving the contradiction between these two properties.
Data Source
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AI summary
An indexable insert (1) includes a substrate (8) and a coating layer formed on the substrate. The coating layer includes an inner layer and an outer layer. The inner layer is constituted by a layer containing at least one element selected from the group consisting of Group IVa elements, Group Va elements, and Group VIa elements in the periodic table, and Al and Si. The uppermost layer of the inner layer in contact with the outer layer is composed of a compound at least containing Ti and at least one of nitrogen and boron. The outer layer is constituted by an alumina layer or an alumina-containing layer. In a region involved in cutting, the outer layer satisfies B/A ≤ 0.9 where A µm is the average thickness at the flank face (3) side and B µm is the average thickness at the rake face (2) side.