Cemented Carbide Tool Assembly for Weldable Hard Cutting Edges
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Solution Overview
Problem
Existing tools for machining abrasive and hard mineral building materials face challenges in attaching sintered hard metal cutting edges to steel carriers due to high welding voltages and differing hardness levels, leading to mechanical stress and complex geometry issues during sintering.
Innovation Solution
A tool with a base body made of low-alloy steel and cutting edges composed of cemented carbide with a cobalt-nickel-based binder, where the binder composition differs between the working area and base, reducing binder migration and achieving a hardness gradient that facilitates easier attachment and sintering without equalizing hardness, thus avoiding mechanical stress and allowing for complex geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sintered hard metal cutting edges with high hardness are used for machining abrasive mineral building materials, then machining efficiency is improved, but attachment to steel carriers becomes difficult due to high welding voltages
Solution Approach 1:
The patent applies local quality by creating a hardness gradient within the cutting edge structure. The working area (tip and cutting edges) maintains very high hardness (>1300 HV10) for effective machining, while the base area has reduced hardness (<800 HV10) to facilitate welding attachment to steel carriers. This spatial differentiation of material properties resolves the contradiction between machining efficiency and attachment ease.
Solution Approach 2:
The patent changes the hardness parameter spatially within the cutting edge. The binder composition is adjusted between the working area and base area, resulting in different hardness values. The working area contains at least 82% by volume tungsten carbide with cobalt-nickel binder for high hardness, while the base area has modified composition achieving lower hardness for easier welding, thus resolving the attachment difficulty contradiction.
2Ease of manufacture
If the base area is made softer to facilitate welding attachment, then ease of manufacture is improved, but the hardness equalizes with the working area, reducing machining effectiveness
Solution Approach 1:
The patent implements local quality by differentiating the binder composition between the working area and base area. The working area uses a binder with specific properties to maintain very high hardness for effective cutting, while the base area uses a modified binder composition to achieve lower hardness for easy welding. This localized material differentiation ensures both machining effectiveness and manufacturing ease without hardness equalization.
3Adaptability or versatility
If different material compositions are used for the working area and base, then functionality is improved, but different shrinkage behavior during sintering causes internal mechanical stresses
Solution Approach 1:
The patent carefully controls the composition parameters of the binder in different areas. The working area contains at least 82% by volume tungsten carbide with a cobalt-nickel-based binder, while the base area has a specifically formulated composition. These parameter changes are optimized to achieve functional differentiation while minimizing shrinkage differential during sintering, thereby reducing internal mechanical stresses and maintaining structural strength.
4Productivity
If the binder composition is optimized for high hardness in the working area, then machining performance is improved, but binder migration occurs during sintering, equalizing hardness between areas
Solution Approach 1:
The patent applies local quality by creating distinct binder compositions in the working area and base area. The working area binder is optimized for high hardness with specific cobalt-nickel ratios, while the base area binder is formulated to prevent migration and maintain lower hardness. This localized composition optimization ensures both high machining performance and stable hardness distribution during and after sintering.
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 solution enables effective attachment of hard metal cutting edges to steel carriers with reduced mechanical stress and allows for the production of complex geometries, ensuring the cutting edges maintain high hardness for efficient machining while the base can be easily welded onto steel, improving processing efficiency.
Implementation Method 1
The cutting edge consists of a hard metal. The cemented carbide contains at least 82% by volume of tungsten carbide and a metallic binder made of a cobalt-nickel-based alloy. The base consists of a sintered composite.
Implementation Method 2
The different composition of the binder in the working area and the base causes a reduction in the migration of the metallic binder.
Data Source
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AI summary
The invention relates to a tool for machining materials, having a main part (4, 34) and one or more blades (6, 38). The main part (4, 34) is made of a low-alloy steel. The socket (17, 39) is welded to the main part (4, 34), and the blade edges (8, 41) consist of a hard metal. The hard metal contains at least 82 vol.% of tungsten carbide and a metal binder made of a cobalt-nickel-based alloy. The hardness of the hard metal is greater than 1350 HV10. The socket (17, 39) consists of a sintered composite, and 40 vol.% to 60 vol.% of the composite is composed of a metal carbide and a metal binder. At least 95 vol.% of the metal binder consists of nickel, and the hardness of the composite is less than 800 HV10.