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Component nonuniformity numerical prediction method for magnesium alloy casting parts

A technology for numerical prediction and casting, which is used in electrical digital data processing, special data processing applications, instruments, etc. It can solve the problems of inability to accurately predict macrosegregation of magnesium alloy castings and uneven composition of magnesium alloy castings, and achieve market applications. Great potential to accurately predict the effects of segregation formation

Active Publication Date: 2019-09-17
HARBIN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that the existing methods cannot accurately predict the formation of macro-segregation of magnesium alloy castings, and propose a numerical prediction method for the compositional inhomogeneity of magnesium alloy castings

Method used

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  • Component nonuniformity numerical prediction method for magnesium alloy casting parts
  • Component nonuniformity numerical prediction method for magnesium alloy casting parts
  • Component nonuniformity numerical prediction method for magnesium alloy casting parts

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specific Embodiment approach 1

[0036] Embodiment 1: In this embodiment, a method for numerically predicting the compositional inhomogeneity of magnesium alloy castings has a specific process as follows:

[0037] Step 1, using the cellular automata method to simulate the growth of α-Mg dendrites with different growth orientations, and obtaining the dendrite specific surface area versus solid phase fraction variation curve;

[0038] Step 2. Carry out macro-scale grid division for the casting system, and adopt the same grid division step size Δx meters=Δy meters for the X-axis and Y-axis directions of the casting system Cartesian coordinate system;

[0039] Δx=X max -Xmin , Δy=Y max -Y min ;

[0040] The calculation label is (js, ks) char The subscript char=2 indicates the casting grid, the subscript char=0 indicates the casting grid, and the subscript char=4, 5, 6, 7 and 8 respectively indicate the internal cooling iron grid and the external cooling iron grid grid, riser sleeve grid, thermal insulation m...

specific Embodiment approach 2

[0048] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the cellular automata method is used to simulate the growth of α-Mg dendrites with different growth orientations in the step 1, and the dendrite specific surface area varies with the solid phase fraction. Change curve; the specific process is:

[0049] Step 1 (1), divide the dendrite growth calculation domain (already determined) into a micro-scale grid, using a square grid with a side length of Δstep, and each square grid is marked with (j, k), j The value range of k is [1, n], the value range of k is [1, m], j and k are integers, n and m are integers, j is the coordinate on the X-axis of the Cartesian coordinate system, k is the coordinate on the Y axis of the Cartesian coordinate system;

[0050] Step 1 (2), assign neighbor objects to each square grid in the computational domain, and complete dendrite growth by capturing neighbor objects;

[0051] The labels are (j∈[1,2]...

specific Embodiment approach 3

[0080] Specific embodiment three: what this embodiment is different from specific embodiment one or two is, in described step one (3), determine the state of each square grid in the solidification process; Concrete process is:

[0081] The boundary grid defined in step 1 (2) can only be in a liquid state, that is, state (j, k) = 0, and state is the state of the grid; the remaining grids have three states:

[0082] when f s When (j, k) = 0, the grid (j, k) is liquid, that is, state (j, k) = 0;

[0083] When 0s When (j, k)<1, the grid (j, k) is in a growing state, that is, state(j, k)=1;

[0084] when f s (j, k) = 1 and the pairing grid (pairing is the following 1-6 pairing method) f s is also equal to 1, then the grid (j, k) is solid, that is, state (j, k) = 2;

[0085] f s (j, k) is the solid phase fraction of the grid (j, k) (the solid phase fraction of the grid (j, k) that divides the dendrite growth calculation domain (already determined) into a micro-scale grid).

[...

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Abstract

The invention discloses a component nonuniformity numerical prediction method for magnesium alloy casting parts, and relates to a component nonuniformity numerical prediction method for magnesium alloy casting parts. The objective of the invention is to solve the problem that macrosegregation formation of the magnesium alloy casting parts cannot be accurately predicted by an existing method. The component nonuniformity numerical prediction method comprises the following steps: 1, simulating the growth of alpha-Mg dendrites with different growth orientations by adopting a cellular automaton method to obtain a curve that the specific surface area of the dendrites changes along with the solid phase fraction; 2, performing mesh generation on the casting system; 3, calculating an energy, component and momentum conservation equation for all grids with subscript char = 0, and obtaining distribution of temperature, average component and speed in the casting parts; 4, calculating an energy conservation equation for all grids of which the subscript chars are not 0 to obtain temperature distribution; and 5, repeating the step 2, the step 3 and the step 4 until solidification is finished, and outputting an average component field in the casting parts. The component nonuniformity numerical prediction method is applied to the field of magnesium alloy casting part component prediction.

Description

technical field [0001] The invention relates to a method for numerically predicting composition inhomogeneity of magnesium alloy castings. Background technique [0002] Magnesium alloy has a series of advantages such as light specific gravity, high specific strength and specific stiffness, and good damping and shock absorption performance, and is an important lightweight material. Magnesium alloy castings have broad application prospects in the fields of national defense, aerospace and automobiles. Casting is the main process for forming them. Therefore, improving the quality of magnesium alloy castings is of great significance to the development of my country's industry. Uneven composition is a casting defect that is easily formed during the solidification of castings, also known as segregation. The segregation on the macro scale is macro segregation, the alloy composition after solidification is higher than the initial alloy composition is called positive segregation, and...

Claims

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Application Information

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IPC IPC(8): G06F17/50
CPCG06F30/20
Inventor 刘东戎朱泓宇赵红晨赵思聪郭二军
Owner HARBIN UNIV OF SCI & TECH
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