Hard Metal Coated Chisel for Wear-Resistant Tool Heads
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Solution Overview
Problem
Existing insert tools, such as chisels and drills, suffer from reduced durability due to the difference in hardness between the main body and the workpiece, leading to premature wear and tear.
Innovation Solution
A coating comprising a hard metal with a metal matrix, such as tungsten carbide and a cobalt alloy, is applied to the tool head and shaft region using a plasma transfer arc process, enhancing the hardness and durability of the insert tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the main body is made from high-speed steel or hardening steel, then the tool structure is maintained and ease of manufacture is improved, but the durability and wear resistance deteriorate due to insufficient hardness compared to the workpiece
Solution Approach 1:
The patent applies a hard metal coating comprising tungsten carbide particles in a metal matrix (cobalt, nickel, or iron-based) onto the tool body. This creates a composite structure where the soft steel substrate provides structural integrity while the hard coating layer (hardness 1700-3100 HV0.1) provides wear resistance, resolving the contradiction between ease of manufacture and durability.
Solution Approach 2:
The hard metal coating is applied selectively to specific regions of the tool that require enhanced wear resistance, such as the tool head and cutting edges, while the shaft region maintains the base steel properties. This localized application improves durability where needed without compromising the overall manufacturability and structural properties of the tool.
2Reliability
If a hard metal coating is applied to enhance durability, then the wear resistance and service life are improved, but the complexity of the manufacturing process increases
Solution Approach 1:
The patent replaces traditional mechanical hardening methods with a plasma transfer arc coating process. This thermal-spray technique deposits the hard metal coating in a controlled manner, allowing for consistent quality and reduced manual intervention, thereby managing process complexity while achieving enhanced durability.
Solution Approach 2:
The coating process utilizes controlled variation of plasma parameters (temperature, particle velocity, deposition rate) to optimize coating quality. By adjusting these parameters, the process achieves reliable coating application without requiring overly complex equipment or multi-step procedures, balancing durability improvement with manufacturing simplicity.
3Reliability
If the coating is applied using plasma transfer arc process, then the hardness and wear protection are significantly improved, but heat exposure to the main body increases
Solution Approach 1:
The plasma transfer arc coating is applied in periodic intervals rather than continuously, allowing heat to dissipate between deposition cycles. This pulsed application method builds up the protective coating layer by layer while controlling the cumulative heat exposure to the steel substrate, preventing thermal damage while achieving the desired hardness and wear resistance.
Solution Approach 2:
The coating application is segmented into multiple passes or zones, with the plasma arc targeting specific regions sequentially. This segmentation allows heat management by limiting the duration of thermal exposure at any single location, while still achieving comprehensive coating coverage and enhanced durability across the tool surface.
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 coating significantly improves the durability and longevity of the insert tool by providing localized reinforcement and protection against wear, while minimizing heat exposure to the main body during application.
Implementation Method 1
A coating comprising a hard metal with a metal matrix, such as tungsten carbide and a cobalt alloy, is applied to the tool head and shaft region using a plasma transfer arc process
Data Source
AI summary
An application tool, in particular a chisel or a drill bit, is disclosed. The application tool has a tool head. The application tool further has a shank region in which a main body is arranged, wherein the main body has a first hardness. The application tool further has a coating that has a second hardness greater than the first hardness. The coating includes a hard metal, which comprises a hard material and a metal matrix. Advantageously, the durability of the application tool can be increased as a result.