Chromium-Free Thermal Spray Composition for Downhole Wear
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Solution Overview
Problem
Downhole tools in oilfield applications face challenges with wear resistance, friction, and attachment methods that often result in heat-affected zones or inadequate holding forces, and existing hardfacing methods like thermal spraying can be inefficient and pose health hazards due to chromium use.
Innovation Solution
A chromium-free thermal spraying composition with specific weight percentages of elements like carbon, manganese, silicon, nickel, molybdenum, aluminum, vanadium, titanium, niobium, boron, and tungsten is applied using a twin-wire thermal sprayer to form a layer on downhole components without creating a heat-affected zone, enhancing wear resistance and attachment strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermal spraying is used to coat tools, then wear resistance is improved, but bonding quality and structural characteristics deteriorate when built up to thick layers
Solution Approach 1:
The patent changes the material composition parameters by formulating a chromium-free alloy with specific ratios of iron, carbon, manganese, silicon, nickel, molybdenum, aluminum, vanadium, titanium, boron, and other elements. This compositional parameter change enables the material to achieve both high wear resistance and reliable bonding without the structural defects associated with traditional chromium-based thermal spray materials.
2Strength
If thermal spraying employs chromium-containing materials, then wear resistance is improved, but health and safety issues worsen requiring special handling procedures
Solution Approach 1:
The patent extracts and removes chromium from the thermal spray composition entirely, replacing it with a chromium-free alloy system that achieves comparable or superior wear resistance through alternative elements such as iron, manganese, silicon, nickel, molybdenum, aluminum, vanadium, titanium, boron, and tungsten. This extraction eliminates the harmful health and safety issues associated with chromium handling while maintaining the desired functional performance.
3Strength
If welding is used to attach tools to tubular, then attachment strength is improved, but heat-affected zone creates diminished strength and corrosion resistance
Solution Approach 1:
The patent replaces the thermal welding process with a mechanical attachment system using a retention ring that engages with grooves in the tool flange. This mechanical substitution eliminates the heat-affected zone entirely while providing sufficient attachment strength through the retention ring's engagement with the groove structure, avoiding the metallurgical damage associated with welding.
4Object-affected harmful factors
If set screws and adhesive are used to attach tool to tubular, then heat-affected zone is avoided, but holding force and corrosion resistance deteriorate
Solution Approach 1:
The patent employs a retention ring with a curved or tapered geometry that engages with correspondingly shaped grooves in the tool flange. This curved engagement design provides progressive locking action and distributed load bearing, achieving superior holding force compared to flat-set screws or adhesive while maintaining avoidance of heat-affected zones through purely mechanical attachment.
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 provides improved wear resistance, reduced friction, and secure attachment without altering the metallurgical properties of the substrate, while minimizing health risks associated with chromium handling.
Implementation Method 1
melting a portion of the one or more wires by applying an electrical current to the one or more wires, to melt the material in the portion
Implementation Method 2
feeding a gas to the sprayer, such that the material is projected through a nozzle of the sprayer, and depositing the material onto the downhole component
Implementation Method 3
depositing the material onto the downhole component, such that the material solidifies and forms into a layer of material
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A composition, method for depositing the composition on a downhole component, and a downhole tool. The composition includes about 0.25 wt% to about 1.25 wt% of carbon, about 1.0 wt% to about 3.5 wt% of manganese, about 0.1 wt% to about 1.4 wt% of silicon, about 1.0 wt% to about 3.0 wt% of nickel, about 0.0 to about 2.0 wt% of molybdenum, about 0.7 wt% to about 2.5 wt% of aluminum, about 1.0 wt% to about 2.7 wt% of vanadium, about 1.5 wt% to about 3.0 wt% of titanium, about 0.0 wt% to about 6.0 wt% of niobium, about 3.5 wt% to about 5.5 wt% of boron, about 0.0 wt% to about 10.0 wt% tungsten, and a balance of iron.