EP1714717A1 - Méthode de prédiction de la défaillance des matrices - Google Patents

Méthode de prédiction de la défaillance des matrices Download PDF

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Publication number
EP1714717A1
EP1714717A1 EP06008110A EP06008110A EP1714717A1 EP 1714717 A1 EP1714717 A1 EP 1714717A1 EP 06008110 A EP06008110 A EP 06008110A EP 06008110 A EP06008110 A EP 06008110A EP 1714717 A1 EP1714717 A1 EP 1714717A1
Authority
EP
European Patent Office
Prior art keywords
die
formula
dies
brittle fracture
predicting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP06008110A
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German (de)
English (en)
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EP1714717B1 (fr
Inventor
Hiroaki c/o Daido Steel Co. Ltd. Yoshida
Shigekazu c/o Daido Steel Co. Ltd. Itoh
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daido Steel Co Ltd
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Daido Steel Co Ltd
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Publication date
Application filed by Daido Steel Co Ltd filed Critical Daido Steel Co Ltd
Publication of EP1714717A1 publication Critical patent/EP1714717A1/fr
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Publication of EP1714717B1 publication Critical patent/EP1714717B1/fr
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J13/00—Details of machines for forging, pressing, or hammering
    • B21J13/02—Dies or mountings therefor

Definitions

  • the present invention concerns a method of predicting damages of dies. More specifically, the invention concerns predicting damages in dies for plastic processing of metals, typically, forging dies by predicting "great crack” damage caused by brittle fracture which dominates die lives, and utilizing the results for die design including choice of materials, hardness thereof and determining the die configuration so as to establish countermeasures for prolongation of die lives.
  • Fracture factors causing damage of forging dies during using are four, namely, "great crack” or static brittle fracture, plastic flow, abrasion and low cycle fatigue destruction.
  • the brittle fracture is a sudden phenomenon occurring at an initial stage before substantial use of the die, and also called “initial crack", which is a fatal damage.
  • methods of predicting damage of dies proposed so far are not effective for this kind of brittle fracture.
  • Cockroft's formula Oyane's formula and Ayada's formula, which have been acknowledged. These formulae are, however, not applicable to the brittle fracture.
  • formula or formulae which enable effective prediction of damage of dies caused by brittle fracture.
  • the object of the present invention is to provide a method of predicting damage of dies enabling design of improved dies by predicting brittle fracture which give, among various factors causing damage to forging die, fatal influence to die lives.
  • the method according to the invention achieving the above-mentioned object is a method of predicting "great crack" by brittle fracture which dominates the lives of dies for plastic processing of metals to contribute to die design including choice of materials, hardness and configuration of the die.
  • the method of predicting damages of dies according to the invention is characterized in that the die design is carried out by choosing the condition that none of the predicted values of brittle fracture, F c1 to F c3 , calculated by the formulae 1 to 3 below exceed the critical values determined on the basis of the material used.
  • the method of predicting damages of dies according to the invention may exhibit the performance to the dies for forming. It will be, however, applicable to other dies such as those for die-casting, which are used under similar environment of high temperature and high stress. Through the prediction of damages of dies desired properties of die materials may be known as a matter of course and the indices for developing the die materials can be obtained. Thus, the invention may contribute to development of alloy technologies.
  • SKD61 one of the steels for hot processing tools, was used as the die material and the hardness was adjusted to be HRC 46, 49 or 52.
  • JIS No.4 tensile test pieces were prepared and some of them were subjected to machining to provide surrounding V-shaped notches of depth 50%. The shapes and dimensions of the test pieces are shown in Fig. 1 (smooth surface), Fig. 2 (notch angle 30°), Fig. 3 (90°) and Fig. 4 (120°). Curvature of the bottom of the notches is 0.2mm.
  • the test pieces were subjected to tensile tests to determine mean normal stress ( ⁇ m ) at which fracture occurs and at the same time whether the fracture is ductile fracture or brittle fracture was recorded.
  • the equivalent stress ( ⁇ eq ) and the maximum principal stress ( ⁇ 1max ) were calculated.
  • Fig. 5 By plotting the mean normal stress ( ⁇ m ) in correspondence of the equivalent stress ( ⁇ eq ) there was obtained Fig. 5, by plotting the mean normal stress ( ⁇ m ) in correspondence of the maximum principal stress ( ⁇ 1max ), Fig. 6, and plotting the maximum principal stress ( ⁇ 1max ) in correspondence of the equivalent stress ( ⁇ eq ), Fig. 7, respectively.
  • the prediction of die life according to the present invention was carried out in regard to a ring-die, a die for limiting the outer surface of the work forged by a punch and a counter punch from top and bottom used for hot forging a final gear, an automobile part, having the cross section shown in Fig. 8.
  • a used die made of SKD61 steel was inspected and it was found that crack of the ring-die occurred from the outer surface.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Forging (AREA)
EP06008110A 2005-04-19 2006-04-19 Méthode de prédiction de la défaillance des matrices Active EP1714717B1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2005120660A JP4556753B2 (ja) 2005-04-19 2005-04-19 金型の損傷予測方法

Publications (2)

Publication Number Publication Date
EP1714717A1 true EP1714717A1 (fr) 2006-10-25
EP1714717B1 EP1714717B1 (fr) 2008-04-02

Family

ID=36648542

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06008110A Active EP1714717B1 (fr) 2005-04-19 2006-04-19 Méthode de prédiction de la défaillance des matrices

Country Status (4)

Country Link
US (1) US20060230881A1 (fr)
EP (1) EP1714717B1 (fr)
JP (1) JP4556753B2 (fr)
DE (1) DE602006000842T2 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6232934B2 (ja) * 2013-10-31 2017-11-22 新日鐵住金株式会社 材料特性取得方法及び装置、並びにプログラム及び記録媒体
KR101867728B1 (ko) * 2016-12-21 2018-06-14 주식회사 포스코 금형 설계 방법
JP6414770B1 (ja) * 2017-03-24 2018-10-31 日立金属株式会社 金型の寿命予測方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000246394A (ja) * 1999-03-02 2000-09-12 Hitachi Metals Ltd 金型の寿命予測方法
JP2002001475A (ja) * 2000-06-23 2002-01-08 Toyota Motor Corp 鍛造工程設計方法
JP2002321032A (ja) * 2001-04-27 2002-11-05 Toyota Motor Corp 金型摩耗量予測装置、金型摩耗量予測方法、金型摩耗量予測プログラム、金型寿命予測装置、金型寿命予測方法、金型寿命予測プログラム、金型摩耗量検出装置、金型寿命検出装置

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3848453A (en) * 1970-08-04 1974-11-19 Alusuisse Die for shaping metals
US4131596A (en) * 1977-08-22 1978-12-26 Logic Devices, Inc. Sensing system and method for plastic injection molding
US4574633A (en) * 1983-02-04 1986-03-11 Citizen Watch Company Limited Apparatus for detecting tool damage in automatically controlled machine tool
JPS63216942A (ja) * 1987-03-05 1988-09-09 Sumitomo Electric Ind Ltd 温、熱間鍛造用工具
JP3250696B2 (ja) * 1993-12-27 2002-01-28 本田技研工業株式会社 成形型の製造方法
JP3800261B2 (ja) * 1996-12-13 2006-07-26 日立金属株式会社 金型寿命の予測方法及びそれを用いた金型材の最適物性値の予測方法
US6572796B1 (en) * 2000-10-27 2003-06-03 General Electric Company Method of predicting optimal injection molding cycle time
JP2006326606A (ja) * 2005-05-23 2006-12-07 Daido Steel Co Ltd 金型寿命の予測方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000246394A (ja) * 1999-03-02 2000-09-12 Hitachi Metals Ltd 金型の寿命予測方法
JP2002001475A (ja) * 2000-06-23 2002-01-08 Toyota Motor Corp 鍛造工程設計方法
JP2002321032A (ja) * 2001-04-27 2002-11-05 Toyota Motor Corp 金型摩耗量予測装置、金型摩耗量予測方法、金型摩耗量予測プログラム、金型寿命予測装置、金型寿命予測方法、金型寿命予測プログラム、金型摩耗量検出装置、金型寿命検出装置

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
KIM ET AL: "Estimation of die service life against plastic deformation and wear during hot forging processes", JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, ELSEVIER, AMSTERDAM, NL, vol. 166, no. 3, 20 August 2005 (2005-08-20), pages 372 - 380, XP005023923, ISSN: 0924-0136 *
PATENT ABSTRACTS OF JAPAN vol. 2000, no. 12 3 January 2001 (2001-01-03) *
PATENT ABSTRACTS OF JAPAN vol. 2002, no. 05 3 May 2002 (2002-05-03) *
PATENT ABSTRACTS OF JAPAN vol. 2003, no. 03 5 May 2003 (2003-05-05) *

Also Published As

Publication number Publication date
JP4556753B2 (ja) 2010-10-06
JP2006297429A (ja) 2006-11-02
DE602006000842T2 (de) 2009-05-20
DE602006000842D1 (de) 2008-05-15
US20060230881A1 (en) 2006-10-19
EP1714717B1 (fr) 2008-04-02

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