AlCrVBN Hard Coating for Cutting Tools
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Solution Overview
Problem
Conventional AlCrN hard covering films for cutting tools exhibit insufficient wear resistance against iron and steel materials despite improved heat resistance, and existing solutions fail to adequately enhance both hardness and lubricating properties.
Innovation Solution
A hard covering film with a specified composition and layer structure, featuring alternating layers of Al-Cr-V-B-N and Al-Cr-V-B-N with varying B and V content proportions, a third covering film layer between the substrate and the multi-layer film, and a fourth nitride or carbide layer on top, enhancing hardness and lubricating properties while maintaining toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If AlCrN covering film is used to improve heat resistance, then heat resistance is improved, but hardness and wear resistance become insufficient
Solution Approach 1:
The patent applies composite materials by combining multiple elements (Al, Cr, V, B, N) in specific proportions to create a covering film that achieves both high heat resistance and high hardness. The composite composition Al(100-x-y-z)Cr(x)V(y)B(z)N with 20≤x≤40, 2≤y≤15, and 5≤z≤15 creates a material that simultaneously provides thermal stability and mechanical strength, resolving the contradiction between heat resistance and hardness.
2Temperature
If AlCrN covering film is used to improve heat resistance, then heat resistance is improved, but wear resistance against iron and steel materials becomes insufficient
Solution Approach 1:
The patent uses composite materials with specific element combinations (Al, Cr, V, B, N) in controlled proportions to achieve both heat resistance and wear resistance. The presence of V (2-15 at%) and B (5-15 at%) in addition to Al and Cr creates a composite structure that provides both thermal stability and resistance to wear against iron and steel materials.
Solution Approach 2:
The patent applies local quality by creating a covering film with specific compositional characteristics optimized for wear resistance against iron and steel materials. The controlled proportions of V and B elements create localized properties within the film structure that enhance wear resistance specifically for ferrous materials while maintaining heat resistance.
3Strength
If covering film composition is optimized for hardness, then hardness is improved, but lubricating properties deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional parameters (x, y, z) of the covering film where Al(100-x-y-z)Cr(x)V(y)B(z)N with 20≤x≤40, 2≤y≤15, and 5≤z≤15. By adjusting these parameters within specific ranges, the patent achieves an optimal balance between hardness and lubricating properties, where Cr contributes to hardness while V and B provide lubricating characteristics.
Data Source
AI summary
It is an object of the present invention to provide a hard covering film for a cutting tool which can improve the wear resistance beyond that of a conventional AlCrN film. According to the present invention, there is provided a hard covering film for a cutting tool formed on a cutting tool substrate, characterized in that: the hard covering film comprises a first multi-layer covering film layer formed by alternatingly layering two or more layers each of a first covering film layer and a second covering film layer; the first covering film layers have metal and semi-metal components that are expressed (in terms of at%) by Al(100-x-y-z)Cr(x)V(y)B(z) (where 20 ≤ x ≤ 40, 2 ≤ y ≤ 15, and 5 ≤ z ≤ 15), have N as a non-metallic element, and have unavoidable impurities; the second covering film layers have metal and semi-metal components that are expressed (in terms of at%) by Al(100-u-v-w)Cr(u)V(v)B(w) (where 20 ≤ u ≤ 40, 0 ≤ v ≤ 5, 0 ≤ w ≤ 5), have N as a non-metallic element, and have unavoidable impurities; the relationship between y and v such that y ≥ v is satisfied; and the relationship between z and w such that z - 5 ≥ w is satisfied.