• 제목/요약/키워드: deep drawability

검색결과 63건 처리시간 0.034초

SUS-Al-Mg이종판재의 드로잉성형에 관한 연구 (A Study on the Clad Sheet Metal of the Warm Drawability)

  • 이영선;정택우;권용남;이정환;최상운
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2008년도 추계학술대회 논문집
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    • pp.71-74
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    • 2008
  • The clad sheet is the sheet metal that joined the one or more material with the different property by rolling process. In this study, it is investigated about the mechanical property or formability of SUS-Al-Mg clad sheet. The clad sheet was formed at elevated temperature because of their poor formability at room temperature. The tensile test was confirmed at various temperature and the reduction of strain rate above $250^{\circ}C$. LDR(Limited Drawing Ratio) was obtained through deep drawing test to confirm the formability of the clad sheet. The FE analysis is performed to compare prototype products.

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인장드로잉법에 의한 원통성형에 관한 실험적 연구 (A Experimental Study of Cup forming by Stretch-Drawing Process)

  • 김영수
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2000년도 춘계학술대회논문집
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    • pp.123-128
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    • 2000
  • Fundamental and informative data of axi-symmetric stretch-drawing of several sheetmetals with thicknesses of 0.7-1.0mm are presented both for single and double operations. Very small radius is applied to the die profile (or-shoulder) ion all operations. to induce wall-thinning by the effect of bending-under-tension from which the name 'stretch-drawing' comes. It is clearly demonstrated that deeper cups could be formed by single and double stretch-drawings from smaller circular blanks due to such wall-thinning action than in the usual deep-drawing of larger blanks, From this fact it is emphasized that the deep-drawability of a sheet metal is not evaluated simply by the conventional L.D.R (limiting drawing ratio) but the depth of the drawn cup should also be taken into account./ Many experimental data about various metals and thicknesses given in this paper offer a valuable information in this process for more general use which recommends to replace the conventional deep-drawing process by the stretch-drawing process both for single and double operations. In the single stretch-drawing it is also confirmed that a deeper cup can be produced by raising the blank-holding force at later stage of operation.

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블랭크 홀딩력 제어에 의한 스탬핑 가공성 향상 기술 (Improvement of the Stamping Formability by BHF Control)

  • 김영석;임성언;손형성;한수식
    • 소성∙가공
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    • 제8권3호
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    • pp.269-275
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    • 1999
  • A variable blank holding force method is proposed to improve deep drawing characteristics of sheet materials. In this method, the blank holding force (BHF) is controlled throughout a drawing process so that the punch load does not exceed a critical value, which is slightly less than the conventional process with the conforming process with the variable BHF is more flexible than the conventional process with the constant BHF and it could be used for improving the product's quality and drawability. In this paper we suggest a method controlling the BHF as a function of punch travel during the forming process. The optimization BHF curves are determined theoretically and experimentally. It is concluded that for the case of optimum BHF control methods the drawn cup height and the drawing formability achieved by this method are increased than those for constant BHF method. Also, as comparing the wall thickness distribution of the cup drawn by the constant BHF and the optimum BHF control, the BHF control reduce the wall thickness variation of the drawn cup at the cup wall and make the cup thickness distribution more uniformly than the constant BHF.

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알루미늄 합금판재의 집합조직 제어 (Texture Control in Aluminum Alloy Sheets)

  • 김근환;강형구;최창희;이동녕
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1997년도 추계학술대회논문집
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    • pp.198-201
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    • 1997
  • Aluminum alloy sheets are considered as one of the high potential substitutes for steel sheets considering weight reduction of automobiles. However, aluminum alloy sheets have drawbacks in higher prices and inferior formability compared to steel sheets. In order to achieve good deep drawability, it is imperative to obtain well developed {111} texture which gives rise to higher plastic strain ratio. It is difficult to obtain this texture from conventional rolling and annealing processes. Therefore, an unconventional rolling process which enhances shear deformation has been experimentally studied to obtain the well developed {111} texture, which in turn gives rise to a substantial increase in plastic strain ratio.

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340MPa 급 초고성형성 고강도강판 개발에 관한 연구 (Study on the Development of 340MPa Grade Super Formable High Strength Steel Sheets)

  • 김용희;이영수;이오연
    • 한국자동차공학회논문집
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    • 제17권4호
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    • pp.48-54
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    • 2009
  • The demand for formable high-strength steel (HSS) sheets has recently increased to reduce the weight of automotive bodies. The 340MPa (Tensile Strength) grade steel sheets are widely used for body inner and outer panels. Especially, super formable 340MPa grade steel sheets with high r-value have an excellent deep drawability compared with the other 340MPa grade steel sheets. It is very available for a part such as rear floor, center floor and dash panels used conventional mild steels up to now. We developed a super formable HSS by optimization of chemical composition, texture control and heat treatment control. It has good mechanical properties with excellent formability (tensile strength: 343MPa, elongation: 41.1% and $\bar{r}=2.1$).

온간성형법에 의한 클래드 강판재의 정사각컵 드로잉성 향상에 관한 연구 (Improvement of Square Cup Drawability of Clad Sheet Metal by Warm Forming Technique)

  • 류호연;김영은;김종호
    • 소성∙가공
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    • 제10권3호
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    • pp.253-260
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    • 2001
  • This study was performed to investigate the optimized warm forming conditions which gave the maximum drawing depth in square cup drawing of clad sheet metals, by changing the temperatures of die and blankholder and also shapes and materials of blanks. Two kinds of clad sheet metals, STS304-A1050-STS304 and STS304-A1050-STS430 were selected for experiments. The relative drawing depth of STS304-A1050-STS304 clad sheet was increased up to 4.4 at $150^{\circ}C$ that was 29% higher than at room temperature, whereas STS304-A1050-STS430 material was improved to 3.9 at $120^{\circ}C$ which was 15% better than at room temperature. In addition, comparison of wall thickness and hardness of a warm drawn cup with those of room temperature showed more even distributions. No separation between each laminated material after drawing occurred through inspection by microscope as well as application of penetrant test and bond strength test. Therefore, warm forming technique was confirmed to give better results in deep drawing of stainless clad sheet metal.

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집합조직과 이랑형표면결함의 제어 및 결정립 미세화 수단으로서의 비대칭압연 (Asymmetric Rolling as Means of Texture and Ridging Control and Grain Refinement)

  • 이동녕
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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    • pp.11-18
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    • 2004
  • Asymmetric rolling, in which the circumferential velocities of the upper and lower rolls are different, can give rise to intense plastic shear strains and in turn shear deformation textures through the sheet thickness. The ideal shear deformation texture of fcc metals can be approximated by the <111> // ND and $\{001\}<110>$ orientations, among which the former improves the deep drawability. The ideal shear deformation texture for bcc metals can be approximated by the Goss $\{110\}<001>\;and\;\{112\}<111>$ orientations, among which the former improves the magnetic permeability along the <100> directions and is the prime orientation in grain oriented silicon steels. The intense shear strains can result in the grain refinement and hence improve mechanical properties. Steel sheets, especially ferritic stainless steel sheets, and aluminum alloy sheets may exhibit an undesirable surface roughening known as ridging or roping, when elongated along RD and TD, respectively. The ridging or roping is caused by differently oriented colonies, which are resulted from the <100> oriented columnar structure in ingots or billets, especially for ferritic stainless steels, that is not easily destroyed by the conventional rolling. The breakdown of columnar structure and the grain refinement can be achieved by asymmetric rolling, resulting in a decrease in the ridging problem.

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온간금형에 의한 클래드판재(STS304-A1050-STS304)의 드로잉성 연구 (A Study on the Drawability of Clad Sheet Metal (STS304-A1050-STS304) by Warm Draw Die)

  • 류호연;김종호;류제구
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2002년도 금형가공 심포지엄
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    • pp.136-143
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    • 2002
  • Warm draw die technique which is one of the new forming technologies to improve formability of sheet metal is applied to the cylindrical and square cup drawing of stainless-aluminum clad sheets. In experiments the temperature of die and blank holder is varied from room temperature to $180^{\circ}C$, while the punch is cooled by circulation of coolant to increase the fracture strength of workpiece on the punch comer area. Test materials chosen for experiments are STS304-A1050-STS304 clad sheets. Teflon film as a lubricant is used on both sides of a workpiece. The limit drawing ratio and relative drawing depth as well as quality of drawn cups(distribution of thickness)are investigated and validity of warm drawing process is also discussed. No separation between each laminated material after drawing occurred through inspection by microscope as well as application of penetrant remover and bond strength test. Therefore, warm forming technique was confirmed to give better results in deep drawing of stainless clad sheet metal.

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0.015% C-1.5% Mn-0~0.5% Mo 강의 어닐링과정에서 미세조직과 집합조직의 변화 (Changes in Microstructure and Texture during Annealing of 0.015% C-1.5% Mn-0~0.5% Mo Steels)

  • 정우창
    • 열처리공학회지
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    • 제24권5호
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    • pp.251-261
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    • 2011
  • The changes in microstructure and texture during annealing were examined in a series of 0.015% C-1.5% Mn cold-rolled sheet steels with 0~0.5% Mo. Orientation distribution function data were calculated from the (110), (200), (211) pole figures determined on the rolled plane of cold-rolled and annealed steel sheets. Regardless of Mo content and annealing conditions, martensite volume fraction was less than 1.0%, not affecting the texture evolution. Textural change at the cooling stage after heating at $820^{\circ}C$ for 67 sec was not observed. Increasing the Mo content and annealing temperature markedly strengthened the intensities of ${\gamma}$-fiber texture, resulting in the increase in $r_m$ value. The desirable texture evolution for deep drawability in the 0.5% Mo steel may be mainly caused by the grain refining effect of Mo carbide in the hot-rolled steel sheet.

비대칭 압연과 열처리한 Cu 판의 집합조직과 소성변형비 변화 (II) (Changes of Texture and Plastic Strain Ratio of Asymmetrically Rolled and Annealed Cu Sheet (II))

  • 이철우;정종현;이동녕;김인수
    • 소성∙가공
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    • 제29권2호
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    • pp.69-75
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    • 2020
  • The plastic strain ratio is one of the factors that affect the deep drawability of metal sheets. The plastic strain ratio of fully annealed Cu sheet is low, due to its texture being {001}<100>. In this study, in order to increase the plastic strain ratio of Cu sheets we investigated the effect of two treatments: 1st the sheet was asymmetrically rolled and annealed, and 2nd the sheet was symmetrically and asymmetrically rolled and subsequently annealed. The average plastic strain ratio (Rm) of the initial Cu sheet was 0.95 and |Δr| was 1.27. After the 2nd treatment of 5.3% symmetric rolling and annealing of Cu sheet at 1000℃ for 60 min in Ar gas condition, the Rm was 2.29 times higher and the |Δr| was 1.44 times higher than that of initial Cu sheet specimen. After the 2nd treatment of 8.2% asymmetric rolling and annealing of Cu sheet at 1000℃ for 60 min in Ar gas conditions, the Rm was 2.51 times higher and |Δr| was 0.53 times lower than that of the initial Cu sheet specimen. These results can be attributed to the change in texture of the Cu sheets due to the differences in the two methods of rolling.