Carbide Refining in High-Carbon High-Alloy Steel via Spray Forming
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Solution Overview
Problem
High-carbon high-alloy steel tends to form coarse eutectic carbides and experiences serious segregation, leading to non-uniform structures that restrict its mechanical properties and wear resistance, with existing manufacturing methods like conventional casting and electroslag remelting failing to effectively address these issues.
Innovation Solution
A carbide refining method involving overheat treatment of high-carbon high-alloy molten steel followed by deposition in a water-cooled copper mold under inert gas, combined with a specific heat treatment process, to achieve a dense structure with fine carbides, improving the microstructure and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional casting method or electroslag remelting method is used, then large-batch industrial production is achieved, but coarse eutectic carbides form and serious segregation occurs
Solution Approach 1:
The patent applies rapid solidification by changing the cooling rate parameter from conventional slow cooling to extremely fast cooling (10^3-10^6 K/s). This parameter change transforms the solidification process, preventing carbide precipitation and segregation that occur in conventional methods, thereby achieving fine microstructure and uniform composition while maintaining industrial production capability
Solution Approach 2:
The patent transitions from conventional bulk solidification to a spray-based process where molten metal is atomized into droplets. This dimensional change from bulk to dispersed droplet form enables rapid heat extraction and uniform cooling throughout the material, eliminating the carbide formation and segregation problems inherent in conventional casting while maintaining productivity
2Manufacturing precision
If spray forming method is used, then structure refinement and composition uniformity are achieved, but yield is low and loose structure with inherent pores forms
Solution Approach 1:
The patent utilizes controlled phase transition from liquid to solid through rapid cooling. By managing the liquid-to-solid transition in a controlled spray atmosphere with optimized cooling rates, the method achieves dense structure formation without the pores and loose structure characteristic of conventional spray forming, while maintaining high productivity through efficient material utilization
3Speed
If degree of overheat is too high, then fluidity is improved for rapid impact, but grains of solidified structure become coarse
Solution Approach 1:
The patent employs dynamic control of the heating and cooling process. The molten metal is heated to a precise temperature range to achieve optimal fluidity for spray atomization, then immediately subjected to rapid cooling. This dynamic approach maintains the balance between fluidity requirements for processing and grain refinement requirements for final structure, preventing both insufficient fluidity and excessive grain growth
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 results in a high-carbon high-alloy steel with a dense and uniform microstructure, refined carbides, enhanced strength, toughness, and wear resistance, thereby improving the service lifetime of the steel.
Implementation Method 1
making the high-carbon high-alloy melt deposited in a preset water-cooled copper mold at a speed of 30 ̃160 g/s by an inert gas, to obtain a high-carbon high-alloy billet through solidification molding
Implementation Method 2
making the high-carbon high-alloy melt deposited in a preset water-cooled copper mold at a speed of 30 ̃160 g/s by an inert gas
Implementation Method 3
in the subsequent heat treatment process, the grains are recrystallized on the basis of dislocation and fragmented primary carbides, to achieve fine grains, fine carbides, and uniform distribution
Data Source
AI summary
The present disclosure provides a carbide refining method of a high-carbon high-alloy steel. The carbide refining method of a high-carbon high-alloy steel includes the following steps: formulating a raw material according to chemical element compositions of the high-carbon high-alloy steel, and smelting to obtain a high-carbon high-alloy molten steel; performing an overheat treatment on the high-carbon high-alloy molten steel to Tm+(50˜100)° C., to obtain a high-carbon high-alloy melt, and making the high-carbon high-alloy melt to be deposited in a preset water-cooled copper mold at a speed of 30˜160 g/s by an inert gas, to obtain a high-carbon high-alloy billet through solidification molding; and performing a heat treatment process on the high-carbon high-alloy billet.