Multilayer Coating Adhesion Prevention for Steel Cutting
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Solution Overview
Problem
Existing cutting tools face significant challenges with adhesion issues when working with various steel materials, particularly those containing lead-free and high-temperature-resistant alloys, leading to reduced tool life and machinability problems due to poor lubricative characteristics and thermal conductivity.
Innovation Solution
A multilayer film-coated member is developed with a first composition hard coating film containing Si, B, C, N, and O, and a second composition hard coating film featuring metals like Al, Ti, Cr, and Ni, where Si-O and B-O bonds form a flux upon heat application, preventing material adhesion by creating a protective layer with optimized bond ratios and oxygen content profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coating films (TiN, CrSiBN, etc.) are used to improve hardness and lubricative characteristics, then cutting performance is improved for specific steel materials, but adhesion prevention fails for various and different steel materials including lead-free and high-temperature-resistant alloys
Solution Approach 1:
The coating film is designed with a specific composition (0.1≤a≤0.5, 0.01≤b≤0.2, 0.05≤c≤0.6, 0.1≤d≤0.7, 0≤e≤0.15) that provides universal adhesion prevention across different steel materials including lead-free and high-temperature-resistant alloys, making it applicable to both mold working and parts working fields regardless of material type
Solution Approach 2:
The invention changes the chemical composition parameters of the coating film by specifying precise ranges for Si, B, N, C, and O content, and by controlling the Si/B atomic ratio within 0.5-5.0, thereby achieving improved adhesion prevention performance across various steel materials
2Object-affected harmful factors
If lead is removed from steel material to reduce environmental load, then environmental performance is improved, but machinability deteriorates and adhesion to cutting tools increases
Solution Approach 1:
The coating film acts as an intermediary layer between the cutting tool and the lead-free steel material, preventing direct contact and adhesion while enabling effective cutting of the environmentally friendly but difficult-to-machine material
3Temperature
If high-temperature-resistant materials (Ti alloy, Ni-base ultra-heat-resistant alloy) are used to resist exhaust gas temperature, then heat resistance is improved, but machinability deteriorates and adhesion to cutting tools increases due to poor thermal conductivity
Solution Approach 1:
The coating film serves as a mediator that facilitates the cutting of high-temperature-resistant materials by preventing adhesion caused by poor thermal conductivity, enabling effective machining of Ti alloys and Ni-base ultra-heat-resistant alloys
4Reliability
If coating film with low affinity to steel material is used to prevent adhesion, then adhesion prevention is improved, but lubricative characteristics deteriorate
Solution Approach 1:
The invention optimizes the chemical composition parameters including Si content (0.1≤a≤0.5), B content (0.01≤b≤0.2), N content (0.05≤c≤0.6), C content (0.1≤d≤0.7), and O content (0≤e≤0.15), along with the Si/B atomic ratio (0.5-5.0), to achieve both low affinity for adhesion prevention and adequate lubricative characteristics
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The multilayer coating effectively prevents adhesion and extends tool life by forming a flux layer that covers the surface, enhancing both heat resistance and abrasion resistance, thereby improving cutting performance and tool longevity across different steel materials.
Implementation Method 1
the Si oxide and the B oxide in the coating film form a flux owing to external heat applied thereto, thereby coating the member surface, and the member may thereby prevent material adhesion thereto
Implementation Method 2
SiO2 and B2O3 undergo eutectic reaction, and form a flux of mixture of SiO2 and B2O3 at a temperature lower than their melting point
Data Source
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AI summary
The invention provides a multilayer film-coated member having sufficient heat resistance and abrasion resistance and capable of exhibiting an effect of preventing adhesion even in cutting work of steel materials that may readily cause adhesion to cutting tools, and therefore capable of prolonging tools, and provides a method for producing it. The multilayer film-coated member is fabricated by coating the surface of a substrate with at least two hard coating films having different compositions, in which the first composition hard coating film of the outermost layer of the hard coating films represented by SiaBbNcCdOe with a+b+c+d+e=1, 0.1 ≤ a ≤ 0.5, 0.01 ≤ b ≤ 0.2, 0.05 ≤ c ≤ 0.6, 0.1 ≤ d ≤ 0.7 and 0 < e ≤ 0.2, the second composition hard coating film of the lower layer below the first composition hard coating film is a hard film having at least two selected from Al, Ti, Cr, Ni, Ce, Mg, Nb, W, Si, V, Zr, and Mo and N and at least one selected from B, C, O and S and in X-ray photoelectric spectrometry (XPS) of the first composition hard coating film, Si-O bond and B-O bond are detected, the ratio of the peak area α of Si-C to the peak area β of Si-O, α/β, as obtained from the peak separation of the 2p orbit of Si, satisfies 10.0 ≤ α/β ≤ 20.0, and the ratio of the peak area X of B-O to the peak area Y of B-N, X/Y, as obtained from the peak separation of the 1s orbit of B, satisfies 5.0 ≤ X/Y ≤ 10.0.