Drill Bit Shank Hardening via Induction Heating
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Solution Overview
Problem
The hardness of the shank in drill bits degrades during the infiltration process, leading to abrasion and potential separation from the diamond tip during drilling, limiting the tool's lifespan and performance.
Innovation Solution
A method involving high-frequency induction heating of the shank's body part to a specific temperature followed by rapid cooling, using a cooling medium to prevent heat transfer to the diamond tip, resulting in a hardened structure with enhanced hardness up to 2 mm from the surface, incorporating microstructures like bainite and martensite for increased durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the shank is inserted into a matrix in a molding state and the upper end of the backing part is fixed, then the drill bit is integrally manufactured via infiltration process, but the shank inevitably experiences high temperature (1000°C or more) which degrades the hardness of the shank
Solution Approach 1:
The shank is divided into two distinct parts: a body part that requires high hardness and an intensified part with enhanced abrasion resistance. This segmentation allows different heat treatment processes to be applied to different sections, resolving the contradiction between maintaining overall structural integrity and preserving local hardness properties.
Solution Approach 2:
High-frequency induction heating and forcible cooling are performed on the body part of the shank before the infiltration process. This preliminary hardening action ensures the shank maintains its hardness despite the subsequent high-temperature infiltration process, preventing hardness degradation.
2Strength
If high-frequency induction heating and forcible cooling are performed on the body part of the shank, then the hardness of the body part is enhanced to 300 Hv or more, but the manufacturing process becomes more complex
Solution Approach 1:
Traditional furnace heating and cooling methods are replaced with high-frequency induction heating and forcible cooling systems. This substitution enables precise, localized heat treatment of the shank body part with faster cycle times and better control, enhancing hardness while managing process complexity through more efficient equipment.
3Reliability
If particles with high hardness are attached on the surface of the shank in the form of a band, then the abrasion degree of the shank is alleviated, but the alleviated degree is not high
Solution Approach 1:
The surface properties of the shank are fundamentally changed through phase transformation during high-frequency heating and forcible cooling. This creates a martensitic or bainitic microstructure with dramatically enhanced hardness and abrasion resistance, far exceeding the effectiveness of simply attaching hard particles to the surface.
4Reliability
If alloy steel with high hardness is used to form the shank, then the abrasion degree is alleviated, but the width for enhancing hardness is restrictive and it is difficult to overcome the problem
Solution Approach 1:
Different sections of the shank are given different properties through selective heat treatment. The body part receives intensive hardening to achieve 300 Hv or more hardness, while the intensified part maintains properties suitable for its functional requirements. This local quality approach provides flexibility in optimizing each section 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 drill bit's shank maintains a hardness of 300 Hv or more for 2 mm from the surface, significantly extending its lifespan and preventing premature wear, making it suitable for drilling through various bedrocks without separating from the diamond tip.
Implementation Method 1
selectively performing rapid heating only on the body part of the shank via high-frequency induction heating
Implementation Method 2
performing rapid cooling via forcible cooling after an infiltration process is completely performed
Implementation Method 3
incorporating microstructures like bainite and martensite for increased durability
Implementation Method 4
using a cooling medium to prevent heat transfer to the diamond tip
Data Source
AI summary
Disclosed are a drill bit for drilling and a method for manufacturing same, in which the hardness of a body part of a shank can be selectively improved by performing rapid cooling in a forced cooling method after performing rapid heating selectively only on the body part of the shank in a high-frequency induction heating method after completing infiltration.