Boronizing Powder Composition for Deep Single-Phase Fe2B Layers
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Solution Overview
Problem
Current boriding powder compositions for metal tubes and pipes often result in shallow dual-phase boride layers, which are prone to fracture and delamination, and fail to achieve the desired single-phase Fe2B layer depth for enhanced wear and corrosion resistance in harsh environments like the oil and gas industry.
Innovation Solution
A new boriding powder composition comprising specific ratios of boron source, activator, sintering reduction agent, and diluent, which slows boron flux to maintain lower surface boron concentration, allowing for deeper single-phase Fe2B boride layer formation, with compositions optimized for various steel alloys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional boriding powder compositions are used, then boron flux into the surface is high, but this results in shallow dual-phase boride layers that are prone to fracture and delamination
Solution Approach 1:
The patent changes the chemical composition parameters of the boriding powder by incorporating specific elements (Ti, V, Cr, Mn, Mo, Ni, Cu, Al, Si, B) in controlled amounts to modify the boron flux rate and control the phase formation during boriding, achieving deeper single-phase Fe2B layers without fracture
Solution Approach 2:
The patent uses a composite powder composition combining multiple boron-containing compounds (CaB6, B4C, FeB, Fe2B) with metal powders and carriers, creating a synergistic effect that controls boron diffusion and promotes single-phase Fe2B formation at greater depths
2Length of stationary object
If high boron flux is used to achieve deeper boride layers, then layer depth increases, but the surface boron concentration becomes too high forming brittle FeB phase that fractures
Solution Approach 1:
The patent modifies the boriding parameters by controlling heating rate, temperature, and time in combination with the specialized powder composition to maintain optimal surface boron concentration that promotes Fe2B formation without excessive FeB, preventing brittleness and fracture
Solution Approach 2:
The patent introduces intermediate elements (Ti, V, Cr, Mn, Mo, Ni, Cu, Al, Si) in the powder composition that act as mediators to control boron diffusion kinetics and phase transformation, preventing direct formation of excessive brittle FeB while enabling deeper Fe2B penetration
3Reliability
If powder pack boronizing is used for pipe interiors, then corrosion resistance improves, but the process requires filling pipes with powder which is impractical for long tubing
Solution Approach 1:
The patent delivers the boriding powder composition through the pipe interior using pneumatic (gas) or hydraulic (liquid) transport systems that convey the powder along the pipe length, making the process practical for long tubing without manual filling
Solution Approach 2:
The patent enables the pipe to serve dual functions: as the workpiece to be borided and as the delivery conduit for the boriding powder, eliminating the need for separate application equipment and simplifying the manufacturing process
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 new composition achieves boride layer depths of 0.010″ to 0.020″ in plain carbon and low alloy steels and 0.005″ to 0.010″ in tool steels, providing high hardness, low porosity, and improved uniformity, reducing the risk of layer fracture and enhancing durability in demanding applications.
Implementation Method 1
reactive boron-containing compounds such as amorphous boron, crystalline ferroboron, boron carbide (B4C), calcium hexaboride (CaB6), or borax react with a halide-based activator upon heating to form gaseous boron trihalides, such as BF3 or BCl3, which react with the metal surface to deposit boron on the surface
Implementation Method 2
The boron is then able to diffuse into the metal structure
Data Source
AI summary
A powder boronizing composition comprising:a. 0.5 to 4.5 wt % of a boron source selected from B4C, amorphous boron, calcium hexaboride, borax or mixtures thereof;b. 45.5 to 88.5 wt % of a diluent selected from SiC, alumina or mixtures thereof;c. 1.0 to 20.0 wt % of an activator selected from KBF4, ammonia chloride, cryolite or mixtures thereof; andd. 10.0 to 30.0 wt % of a sintering reduction agent selected from carbon black, graphite or mixtures thereof.