Cemented Carbide Rock Drill Button with Chromium-Modified Binder
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rock drill buttons made of traditional sintered cemented carbide with tungsten carbide (WC) and cobalt (Co) face challenges in corrosion resistance, wear, and brittleness under severe impact and thermal conditions, particularly in wet drilling and percussive drilling applications.
Innovation Solution
Incorporating chromium (Cr) into the cemented carbide with a specific Cr/Co ratio and WC grain size to enhance corrosion resistance, toughness, and thermal conductivity, while maintaining hardness and preventing brittleness, by adjusting the sintering process to ensure the chromium is dissolved in the cobalt binder phase and avoiding chromium carbide formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chromium is added to sintered cemented carbide to improve corrosion resistance, then corrosion resistance is improved, but the cemented carbide becomes more brittle and has lower toughness
Solution Approach 1:
The invention changes the chemical composition parameters by adding chromium to the cemented carbide, with specific control of Cr content (0.1-2.0 mass%) and Cr/Co ratio (0.043-0.19). This parameter change improves corrosion resistance while the sintering process ensures chromium dissolves in the cobalt binder phase rather than forming brittle chromium carbides, thus maintaining acceptable toughness
Solution Approach 2:
The invention creates a composite material system where chromium is integrated into the existing WC-Co cemented carbide structure. The chromium dissolves in the cobalt binder phase to form a modified binder composition, creating a composite structure that combines the corrosion resistance of chromium with the mechanical properties of the WC-Co system
2Strength
If WC grain size is reduced to increase hardness, then hardness is improved, but thermal conductivity decreases and brittleness increases
Solution Approach 1:
The invention optimizes the WC grain size parameter within a specific range (1.5-5.0 μm mean value). This parameter change balances hardness and thermal conductivity by preventing excessive grain refinement that would reduce thermal conductivity, while still achieving sufficient hardness through the chromium-modified binder phase
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 modified cemented carbide rock drill buttons exhibit improved corrosion resistance, reduced wear, and increased durability, with enhanced thermal conductivity and toughness, allowing for longer drilling performance and reduced brittleness, as demonstrated by field tests and abrasion wear testing.
Implementation Method 1
the sintering process to ensure the chromium is dissolved in the cobalt binder phase
Implementation Method 2
rock drill buttons made of traditional sintered cemented carbide with tungsten carbide (WC) and cobalt (Co)
Data Source
AI summary
A rock drill button having a body of sintered cemented carbide that has hard constituents of tungsten carbide (WC) in a binder phase of Co, wherein the cemented carbide has 4-12 mass % Co and balance WC and unavoidable impurities. The cemented carbide also has Cr in such an amount that the Cr/Co ratio is within the range of 0.043-0.19, and that the WC grain size mean value is above 1.75 μm.