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Mold life prediction method

A technology of life prediction and mold, applied in measurement devices, manufacturing tools, CAD numerical modeling, etc., can solve the problems of repeated trial and error, unclear life improvement, and failure to improve life, and achieve the effect of high-precision thermal fatigue life

Active Publication Date: 2019-04-02
HITACHI METALS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the relationship between the thermal fatigue life of the mold and the material properties of the mold or the thermal stress load is not clear, so it is not clear to what extent the life can be improved without actual application
Therefore, there are cases where the service life is not improved to the expected level, trial and error are repeated, and improvement takes time and cost.

Method used

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Embodiment

[0057] Die-casting was planned to be performed under the conditions in Table 1, and the thermal fatigue life (the number of cracks) of the mold when die-casting was actually performed was predicted. The mold used is as Figure 5 As shown, it is assumed that there are five V-grooves with respective corner radii (bottom radii) on the working surface.

[0058] [Table 1]

[0059]

[0060] First, according to the procedure of (a) above, the temperature distribution of the mold in a series of casting cycles is obtained (step A). As an example of a temperature profile created based on this calculation result, the temperature profile of the working surface at 0.5 seconds after the injection of molten metal into the cavity is completed is shown in Figure 6 middle.

[0061] Next, according to the procedure of (b) above, the thermal stress distribution generated in the mold is obtained from the temperature distribution (step B). As an example of a thermal stress distribution diag...

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Abstract

Provided is a method for predicting the thermal fatigue life of a mold. The method for predicting the thermal fatigue life of a mold made of a mold material having hardness H, in which heating in contact with a workpiece and cooling after the contact with the workpiece are repeated, the method comprising: calculating the temperature distribution of the mold heated through the contact with the workpiece; calculating a thermal stress distribution generated in the mold on the basis of the temperature distribution; calculating, from the thermal stress distribution, a thermal stress maximum value [sigma]h_MAX at a position x of the mold and a temperature Th at the thermal stress maximum value [sigma]h_MAX; calculating, by using the mold material having the hardness H, a yield strength [sigma]y(Th) at the temperature Th and the contraction [phi](Tc) at the temperature Tc of the mold when cooled; and calculating a thermal fatigue life N at the position x of the mold by assigning [sigma]h_MAX,[sigma]y(Th), and [phi](Tc) to the relational formula: N={C1([sigma]y(Th) / [sigma]h_MAX)m.ln (1-[sigma](Tc))-1-C2}n (C1, C2, m, and n are constants).

Description

technical field [0001] The invention relates to a method for predicting the thermal fatigue life of a mold. Background technique [0002] In die-casting dies, hot forging dies, and other dies whose working surfaces are in contact with high-temperature workpieces, heating by contact with the workpiece and cooling by water-soluble mold release agents or lubricants are performed. The mold surface is subjected to compressive and tensile thermal stress. Moreover, in actual operation, due to repeated exposure to this thermal stress, thermal fatigue cracks are generated on the surface of the mold, for example, on the working surface of the mold, and the cracks are transferred to the material to be processed. If the transfer of the cracks becomes severe gradually and the mold cannot be used, the mold will be discarded. Especially in die-casting dies, cracks due to thermal fatigue are the biggest cause of failure, and it is strongly desired to improve the thermal fatigue life. [...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22C9/06B22C9/00B22D17/22G01N3/32
CPCG06F30/23G06F2111/08G06F2111/10G06F2113/22G06F2119/04B22C9/06B22D17/22G01N3/32G01N3/60G06F2119/18
Inventor 森春幸佐藤正尭长泽政幸
Owner HITACHI METALS LTD