Flux-Cored Wire for Molybdenum Steelmaking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for increasing molybdenum content in steel are inefficient, as pure molybdenum is incompatible with steelmaking temperatures and processes, and existing additives require lengthy homogenization times and are difficult to control, leading to incomplete dissolution and costly raw materials.
Innovation Solution
A cored wire with a metal sheath containing a mixture of molybdenum trioxide and a reducing element (carbon, aluminum, or silicon) with carefully determined particle sizes, allowing complete reduction of molybdenum trioxide during heating, ensuring precise molybdenum content adjustment in steel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If molybdenum compounds such as MoO3 are added to liquid steel, then the molybdenum content of steel can be increased, but the melting or decomposition temperature of these compounds is much lower than that of pure molybdenum, making them incompatible with steelmaking temperatures
Solution Approach 1:
The patent uses FeSi (ferrosilicon) as an intermediary substance to facilitate the transfer of molybdenum from MoO3 to the steel bath. The FeSi reacts with MoO3 to form Fe-Mo alloy, which then dissolves into the steel. This intermediary approach allows the use of low-temperature molybdenum compounds while achieving the desired molybdenum content in steel at high steelmaking temperatures.
Solution Approach 2:
The patent changes the physical state and form of molybdenum addition from pure metallic molybdenum (high melting point) to molybdenum oxide compounds (low melting point) combined with FeSi. This parameter change in chemical form enables molybdenum addition at steelmaking temperatures by utilizing compounds with compatible thermal properties.
2Quantity of substance
If Fe-Mo alloy pieces are added to the ladle furnace to increase molybdenum content, then the molybdenum content can be increased, but it requires a relatively long time to develop and homogenize the composition of the liquid steel bath
Solution Approach 1:
The patent segments the Fe-Mo alloy into fine particles by using FeSi powder mixed with MoO3 powder, where the FeSi particle size is controlled to be between 0.045mm and 3mm. This segmentation increases the surface area and accelerates the dissolution rate, reducing the homogenization time from minutes to seconds while maintaining effective molybdenum transfer to the steel bath.
Solution Approach 2:
The patent changes the particle size parameter of the Fe-Mo alloy from large pieces (10-50mm) to fine particles (0.045mm-3mm). This parameter change in particle size dramatically increases the dissolution rate and reduces the time required for composition homogenization in the liquid steel bath.
3Ease of operation
If the particle size of Fe-Mo alloy pieces is large (10-50 mm), then the handling and addition is easier, but the dissolution time increases and the process becomes difficult to control
Solution Approach 1:
The patent optimizes the particle size parameter of FeSi to a specific range (0.045mm-3mm) that balances handling ease with rapid dissolution. This parameter optimization ensures that the material is easy to handle during addition while dissolving quickly in the steel bath, eliminating the trade-off between operational convenience and process speed.
Solution Approach 2:
The patent creates a composite material system consisting of MoO3 powder mixed with FeSi powder in specific proportions. This composite structure combines the low-temperature properties of MoO3 with the rapid dissolution characteristics of fine FeSi particles, achieving both ease of operation and fast dissolution simultaneously.
4Productivity
If FeSi is mixed with MoO3 to create Fe-Mo alloy, then the dissolution rate improves, but the final Mo content requires corrections downstream before solidification
Solution Approach 1:
The patent implements a feedback mechanism by precisely controlling the ratio of FeSi to MoO3 (expressed as FeSi/MoO3 mass ratio) and the particle size distribution. This feedback control ensures that the correct amount of molybdenum is transferred to the steel bath in a single addition, eliminating the need for downstream corrections and achieving precise Mo content control.
Solution Approach 2:
The patent optimizes multiple parameters including the mass ratio of FeSi/MoO3 (0.5-5.0), FeSi particle size (0.045mm-3mm), and MoO3 particle size (0.045mm-10mm) to achieve both rapid dissolution and precise Mo content control. These parameter optimizations ensure complete reaction and accurate dosing, eliminating the need for post-correction.
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
This approach significantly reduces the dissolution time of molybdenum in steel, increases productivity, and allows for late-stage corrections in the steelmaking process, minimizing the risk of incomplete dissolution and reducing raw material costs.
Implementation Method 1
a mixture of powders on the one hand of molybdenum trioxide and on the other hand of at least one reducing element such as Carbon (C), Aluminum (Al) or Silicon (Si) in judiciously determined proportions... the reduction completes the molybdenum trioxide in the metal sheath during the increase in temperature
Implementation Method 2
the reaction time (i.e. the time required for the components present in the core to interact and form the metallic titanium) decreases and the temperature of the core will be relatively high, knowing that this reaction is exothermic
Data Source
Figure 1
AI summary
The invention relates to a flux-cored wire for charging a metallic bath into a state of fusion, comprising a metal sheath and powder filling and characterized in that the filling is a mixture of powders of molybdenum trioxide and moreover at least one reducing component, the molybdenum trioxide being predominant, and in that the proportions and grades of the powder mixture are predetermined so as to obtain complete reduction of the molybdenum trioxide in the metal sheath when the temperature increases due to insertion of the flux-cored wire into the bath. The invention also relates to a method for producing molybdenum-rich steel by means of said flux-cored wire.