High-Vanadium High-Speed Steel with Melt-Impact Carbide Refinement
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Solution Overview
Problem
High-vanadium high-speed steel forms coarse eutectic carbides due to high carbon and alloying element contents, leading to severe segregation and uneven microstructure, which limits mechanical properties and wear resistance, and existing manufacturing methods result in ingots with coarse carbides, porosity, and complex, time-consuming heat treatments.
Innovation Solution
A melt impact method followed by rapid spheroidizing annealing and quenching-tempering treatments to refine grains and carbides, ensuring uniform distribution and improved mechanical properties, including a process that involves smelting specific raw materials, melt impacting, spheroidizing annealing, and quenching-tempering to achieve a dense and uniform ingot microstructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional casting or electroslag remelting is used to mass produce high-speed steel, then production efficiency is improved, but coarse carbides form a continuous network distribution leading to embrittlement and reduced strength and toughness
Solution Approach 1:
The invention segments the carbide distribution by controlling the solidification process to achieve isolated carbide particles instead of continuous network distribution. The melt impact method creates a cooling platform that promotes localized carbide formation separated by metal matrix, breaking the continuous network structure into discrete segments that do not embrittle grain boundaries.
Solution Approach 2:
The invention changes the solidification parameters by using melt impact technology with controlled cooling rates and impact velocities. By adjusting the impact velocity (0.5-2.0 m/s) and cooling platform temperature, the carbide morphology and distribution are transformed from coarse continuous networks to fine isolated particles, resolving the contradiction between production efficiency and mechanical properties.
2Manufacturing precision
If spray molding rapid solidification technology is used, then microstructure refinement and macro-segregation elimination are achieved, but overspray, low yield, loose microstructure, and inherent porosity (up to 20%) occur
Solution Approach 1:
The invention extracts the harmful porosity and loose microstructure characteristics of spray molding by using a different solidification approach. The melt impact method creates a more compact structure upon impact with the cooling platform, eliminating the inherent porosity (up to 20%) and loose microstructure while retaining the microstructure refinement benefits.
Solution Approach 2:
The cooling platform acts as an intermediary medium that receives the impacted melt and controls solidification. This intermediary structure enables the formation of dense, uniform microstructure with minimal porosity by providing a controlled solidification environment that differs from direct spray deposition, thereby improving reliability while maintaining manufacturing precision.
3Strength
If high carbon and alloying element contents are used in high-vanadium high-speed steel, then comprehensive performances are improved, but coarse eutectic carbides form with serious segregation and uneven microstructure
Solution Approach 1:
The invention applies preliminary action by using melt impact to create a controlled solidification structure before heat treatment. The impact process pre-distributes the high carbon and alloying elements into a more uniform pattern, creating a foundation that resists segregation during subsequent processing. This preliminary structuring enables high alloy content while maintaining microstructure homogeneity.
Solution Approach 2:
The melt impact process introduces mechanical energy and vibration during solidification, which helps distribute alloying elements and carbides more uniformly. The impact-induced mixing and controlled cooling prevent the formation of coarse eutectic carbides and serious segregation, enabling high comprehensive performance with improved microstructure stability.
4Manufacturing precision
If complex and time-consuming heat treatment processes are applied to eliminate coarse continuous network carbides, then carbide morphology is improved, but production time and cost increase
Solution Approach 1:
The invention performs the carbide refinement action preliminarily during the solidification stage through melt impact, rather than requiring extensive post-processing heat treatment. The controlled impact and solidification create the desired carbide distribution from the beginning, eliminating or minimizing the need for time-consuming heat treatment processes and reducing production time while maintaining manufacturing precision.
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 method enhances the strength, toughness, and wear resistance of high-vanadium high-speed steel by refining grains and carbides, reducing porosity, and improving mechanical properties, resulting in a high-utilization rate and extended service life.
Implementation Method 1
impact the melt to a cooling platform to form a high-vanadium high-speed steel casting billet
Implementation Method 2
carrying out a spheroidizing annealing treatment on the high-vanadium high-speed steel casting billet to obtain an annealed ingot
Implementation Method 3
performing a quenching and tempering treatment on the annealed ingot
Implementation Method 4
performing a quenching and tempering treatment on the annealed ingot
Data Source
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Figure 3~4
AI summary
The present invention provides a high-vanadium high-speed steel and preparation method therefor, and use thereof, which relate to the technical field of high-vanadium high-speed steel. The preparation method includes: smelting raw materials to form a melt; impacting the melt to a cooling platform to form a high-vanadium high-speed steel casting billet; and performing a spheroidizing annealing treatment and a quenching and tempering treatment, so as to obtain a resultant. The spheroidizing annealing treatment includes: heating the high-vanadium high-speed steel casting billet to 820-910°C; holding for 2-4h; then cooling down to 450-550°C at a cooling rate larger than 40°C/h; and then air cooling to a room temperature. It can play roles of crushing grains and crushing primary carbides when performing the melt impacting, so that the formed ingot microstructure is dense and uniform, and the carbide is fine. The rapid spheroidizing annealing process is used to realize the rapid annealing, so that the carbide in the high-vanadium high-speed steel is not easily agglomerated, and is uniformly distributed in conglobate shape, which is time-saving and high-efficient, and is beneficial to improving the mechanical property of the high-vanadium high-speed steel.