Shear Drawing Die for Continuous Grain Refinement
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Solution Overview
Problem
Existing severe plastic deformation technologies, such as ECAE and ECAD, face limitations in achieving continuous processing and uniform cross-sectional distribution during material drawing, leading to non-uniform material filling and necking issues, particularly in carbon steels undergoing spheroidizing heat treatment.
Innovation Solution
A die for shear drawing is designed with intersecting inlet and outlet paths at a specific angle (120°-160°) and cross-sectional reduction segments to enable simultaneous continuous drawing and shear deformation, ensuring uniform material filling and reducing heat treatment temperature and time for carbon steels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ECAD (equal channel angular drawing) is used to perform continuous drawing, then productivity is improved, but material filling becomes non-uniform and necking occurs
Solution Approach 1:
The die introduces diameter reduction segments that create local variations in channel dimensions. Specifically, the outlet cross-sectional area is reduced compared to the inlet cross-sectional area, creating a gradient that promotes uniform material flow and prevents necking while maintaining continuous drawing capability
Solution Approach 2:
The die geometry parameters are changed by introducing diameter reduction segments with specific reduction ratios (10-60%). The outlet diameter is made smaller than the inlet diameter, and the channel length and reduction ratio are optimized to achieve both continuous processing and uniform cross-sectional distribution
2Manufacturing precision
If ECAE (equal channel angular extrusion) is used to impart severe plastic deformation, then grain refinement is improved, but continuous processing is not possible
Solution Approach 1:
The invention inverts the extrusion process of ECAE by using a drawing process instead. Material is pulled through the die channel rather than being pushed, enabling continuous processing while maintaining the severe plastic deformation and grain refinement effects through the intersecting channel geometry
3Productivity
If drawing process is used to perform continuous processing, then productivity is improved, but severe plastic deformation and grain refinement are not achieved
Solution Approach 1:
The die merges two functions into one: continuous drawing capability and severe plastic deformation through shear. The intersecting channel geometry (inlet and outlet paths at specific angles) combines with the drawing process to generate both continuous material flow and intensive shear deformation for grain refinement
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 shear drawing die achieves ultra-fine grain refinement and improved mechanical properties by increasing effective strain, allowing for reduced heat treatment temperatures and times, while maintaining material uniformity and preventing necking.
Implementation Method 1
ECAE is a process imparting severe plasticity, due to shear deformation, to a metallic material by extruding the metallic material through a die
Implementation Method 2
ECAD capable of obtaining a material having similar characteristics to a material processed through ECAE and imparting severe plastic deformation
Data Source
Figure 1(a)~2
Figure 3~4(b)
Figure 5(a)~5(b)
AI summary
Provided is a die for shear drawing capable of performing continuous drawing and shear deformation at the same time. The die for shear drawing includes a material processing channel in which a material is sheared and drawn while passing therethrough, wherein the processing channel includes an inlet path positioned at a front end thereof, and an outlet path positioned at a rear end thereof, when viewed from a movement direction of a material, the inlet path and the outlet path are connected to intersect central axes thereof at a certain angle, and the processing channel includes a cross-section reduction segment allowing an outlet cross-sectional area of the outlet path to be smaller than an inlet cross-sectional area of the inlet path to thereby draw out a material from an exit of the outlet path with the material filled therein.