Chisel Tool Joining Layer for Fatigue-Resistant Tip Bonding
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Solution Overview
Problem
Existing chiseling tools for mining mineral building materials face issues with the failure of iron-nickel foils due to material fatigue during drilling, leading to unreliable connections between the drill head and the shank.
Innovation Solution
A manufacturing method involving a tool tip made of sintered hard metal and a shank of steel, with an intermediate layer of nickel, nickel-based alloy, and cobalt-based alloy, where the top layer has additives to lower its melting temperature, and inductive heating is used to create a resilient joining zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If iron-nickel foil with thickness of at least 0.3 mm is used as intermediate layer, then welding process is improved, but the foil fails due to material fatigue caused by drilling
Solution Approach 1:
The patent changes the material parameters of the intermediate layer by using a multi-layer structure with different compositions. The first intermediate layer uses nickel-based alloy with specific carbon content (0.05-0.5 wt.%) and chromium content (0.5-5 wt.%), while the second layer uses different alloying elements. This parameter optimization allows the layers to have appropriate strength and ductility to resist fatigue failure during drilling operation.
Solution Approach 2:
The patent applies composite material principle by creating a multi-layer intermediate structure where each layer has distinct compositional characteristics. The first layer contains nickel, carbon, and chromium in specific proportions, while the second layer has different alloying composition. This composite structure combines the advantages of different materials to achieve both strong bonding and fatigue resistance.
2Strength
If inductive heating is used to heat the joining zone to high temperature, then bonding strength is improved, but the steel shank may be damaged if temperature is too high
Solution Approach 1:
The intermediate layers act as thermal intermediaries between the sintered hard metal tool tip and the steel shank. These layers have specific thermal properties that allow them to withstand the high temperatures required for strong bonding while protecting the steel shank from excessive heat. The intermediate layers absorb and distribute the thermal energy, preventing direct thermal damage to the steel substrate.
Solution Approach 2:
The patent applies local quality principle by creating a temperature gradient through the multi-layer structure. The joining zone between the tool tip and intermediate layers reaches high temperatures for strong bonding, while the intermediate layers gradually dissipate the heat, protecting the steel shank from excessive temperature. Each layer experiences different thermal conditions optimized for its specific function.
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 method provides a strong and durable connection between the drill head and the shank, reducing the risk of failure under thermomechanical stresses and improving the tool's performance in drilling mineral materials.
Implementation Method 1
inductive heating of a joining zone between the underside and the end face by means of an induction coil to a temperature that is above the melting temperature of the coating and below the melting temperature of the steel
Implementation Method 2
additives from the material group copper, silver, gold, palladium, boron, silicon, and phosphorus are added to the coating to lower its melting temperature to below 1250 °C
Data Source
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AI summary
The invention relates to a production method for a chiseling tool that provides the following steps: providing a tool tip (2), which is produced from a sintered hard metal and has a bottom side (18); providing a shaft (7), which is produced from a steel and has an end face (22); applying an intermediate layer (25) to either the bottom side (18) of the tool tip (2) or the end face (22) of the shaft (7). The intermediate layer (25) has a base layer (26) and, at least on the surface facing away from the one side, a cover layer (28, 29). The base layer (26) is based on the material group of nickel, nickel-based alloy, cobalt-based alloy and molybdenum. The base layer (26) has a melting point above 1300 °C. The cover layer (29) consists of the material group of nickel, nickel-based alloy, cobalt-based alloy and molybdenum, additives from the material group of copper, silver, gold, palladium, boron, silicon, phosphorus being added to the cover layer (29) in order to lower the melting temperature of the cover layer (28, 29) to below 1250 °C; pressing the tool tip (2) against the shaft (7) by means of a press (31); and inductively heating a joining zone (32) between the bottom side (18) and the end face (22) to a temperature that lies above the melting temperature of the cover layer (29) and below the melting temperature of the steel by means of an induction coil (30).