Pick Tool Brazing Interface Design for Wear Resistance
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Solution Overview
Problem
Pick tools used in mining and excavation experience premature wear and failure due to the abrasive nature of materials they encounter, leading to frequent replacements and inadequate protection of the steel support body, with existing joining methods at non-planar interfaces being inconsistent and prone to failure.
Innovation Solution
A pick tool design featuring a non-planar interface with co-axial and annular surfaces of different widths, which increases the brazing surface area and compressive stresses, encouraging braze material flow inwardly to enhance shear strength and wear resistance, thereby securing the carbide tip to the steel support body effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a non-planar interface is used to join the impact tip to the support body, then the join strength is improved, but the manufacturing consistency is reduced
Solution Approach 1:
The non-planar interface is segmented into multiple planar sub-surfaces (first planar sub-surface and second planar sub-surface) with different orientations. This segmentation allows each sub-surface to be manufactured and joined independently with better control, while collectively providing the enhanced join strength of the non-planar configuration.
Solution Approach 2:
Different regions of the interface are given different local properties through the use of planar sub-surfaces with different orientations and areas. The first planar sub-surface has a different orientation and area than the second, creating local variations that optimize both join strength and manufacturing consistency.
2Reliability
If the impact tip is made of cemented metal carbide, then the wear resistance is improved, but the fracture resistance is reduced
Solution Approach 1:
The impact tip is made of cemented metal carbide, which is a composite material combining carbide grains with a metal binder. This composite structure provides both the wear resistance of carbide and the fracture resistance of the metal binder, resolving the contradiction between these two properties.
3Strength
If the brazing surface area is increased, then the join strength is improved, but the manufacturing complexity is increased
Solution Approach 1:
The brazing interface is segmented into multiple planar sub-surfaces, which simplifies the manufacturing process by allowing each sub-surface to be processed independently. This segmentation reduces the overall manufacturing complexity while maintaining the total brazing surface area for strong join.
Solution Approach 2:
The planar sub-surfaces are designed with different areas and orientations to optimize local brazing conditions. This allows the brazing process to be simplified in each local region while achieving strong overall join through the cumulative effect of multiple localized brazing zones.
4Productivity
If the pick tool operates in abrasive environments, then the productivity is improved, but the tool life is reduced
Solution Approach 1:
The impact tip uses cemented metal carbide, a composite material where carbide grains provide abrasion resistance and the metal binder provides toughness. This composite structure enables the tool to operate in abrasive environments maintaining both productivity and extended tool life.
Solution Approach 2:
The impact tip is designed with a rounded working end, which reduces stress concentration and improves durability in abrasive environments. The curved geometry allows for better material distribution and reduces points of premature wear or fracture.
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 design significantly improves the wear resistance and reliability of the pick tool, ensuring the carbide tip's full lifetime usage while protecting the steel support body, and simplifies quality checking by providing a more consistent and flexible brazing process.
Implementation Method 1
A pick tool comprising a central axis, an impact tip and a support body, the impact tip joined to the support body at a non-planar interface... braze material flow radially inwardly during the brazing process
Data Source
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AI summary
This disclosure relates to a pick tool suitable for road milling. The pick tool comprises a central axis, an impact tip and a support body, and the impact tip is joined to the support body at a non-planar interface. The non-planar interface comprises two co-axial and annular interface surfaces.