• 제목/요약/키워드: Forging effect

검색결과 178건 처리시간 0.024초

냉간 비조질강의 바우싱거 효과에 미치는 변형량의 영향 (Pre-strain Effect on the Bauschinger Phenomenon of Non-Heat Treatable Cold Forging Steel)

  • 하재근;권용남;김상우;이영선;이정환
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2005년도 추계학술대회 논문집
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    • pp.326-329
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    • 2005
  • Since the required strength of forged part is achieved by work hardening with the accumulation of plastic strain during the cold working, severe load can be exerted on die system. So, dies are liable to the early fracture for the non-heat treated steel forging in comparison with the conventional mild steels. Therefore, it is necessary to lower the flow stress of steels as much as possible during forging steps. Bauschinger effect can be utilized to lower flow stress during forging steps by giving the tensile prestrain on the forging billet during wire drawing step. In the present study, the prestrain effect on Bauschinger phenomenon is studied to avoid difficulties with application of non-heat treated cold forging steels in practice.

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원심주조된 내열강의 미세조직 및 기계적성질에 미치는 단조 조건의 영향 (Effect of Forging Condition on the Microstructure and Mechanical Properties in Centrifugal Casted Heat Resistant Steel)

  • 강창룡;이상명;조덕호;박영태;이도훈;김영철
    • 동력기계공학회지
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    • 제13권3호
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    • pp.47-52
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    • 2009
  • The effect of forging start temperature, forging ratio on the microstructure and mechanical properties of B7B4 steel ware investigated. Microstructure of centrifugal casted B7B4 steel consisted of martensite and ferrite phase. The volume fraction of ferrite increased with increase of forging start temperature and decreased with increase of forging ratio. Tensile strength and hardness decreased with higher of forging start temperature, while impact value and elongation increased with higher of forging start temperature. With increase of forging ratio, tensile strength rapidly increased up to the forging ratio of 30%, and then slowly increased, but elongation was decreased. Hardness and impact value rapidly increased with increase of forging ratio.

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비조질강의 바우싱거 효과에 미치는 변형율 영향 (Effect of Pre-strain on the Bauschinger Phenomenon of Micro-Alloying Forging Steel)

  • 권용남;이영선;김상우;이정환
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2005년도 춘계학술대회 논문집
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    • pp.313-316
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    • 2005
  • In the present study, Bauschinger effect was investigated for the micro-alloying forging steel which has been developed for about 30 years ago to save energy consumption by eliminating the heat treatment processes in the forging industry. The micro-alloying steels used fur cold forging industry mainly aim to replace the usual carbon steel. With the conventional carbon steels, all the deformation history can be eliminated after the final heat treatment(quenching and tempering). In the case of micro-alloying forging steels, however, the prior deformation history should be taken into consideration to meet the mechanical property requirement since the microstructure of micro-alloying steels might exhibit the Bauschinger effect, which was not needed to consider in the case of conventional carbon steel having quenching and tempering treatment. In the present study, the reverse loading tests were carried out to determine the Bauschinger effect of micro-alloying steel which composed of ferrite and cementite phases.

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A356 합금의 중력 주조/단조와 Rheo-diecasting/단조의 미세조직 및 기계적 특성 비교 (Comparison of the Microstructure and Mechanical Property between Gravity Casting Forging and Rheo-diecasting Forging using A356 Alloy)

  • 이준영;임재용;이승용;문성원;홍준표
    • 한국주조공학회지
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    • 제33권5호
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    • pp.210-214
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    • 2013
  • Recently, the automotive industry has replaced cast iron to lightweight materials like aluminum for engine efficiency of automobiles and an emission control by government. In this paper we studied two auto parts manufacturing methods using an alloy of A356. That is gravity casting and H-NCM Rheo-diecasting forging. We analyzed the microstructure and mechanical properties for this method. In Microstructure analysis results, H-NCM Rheo-diecasting forging has more finer microstrucre and better forging effect. Resulting in better mechanical properties than gravity forging.

9Cr-1Mo 내열강의 미세조직 및 기계적 성질에 미치는 원심주조 후 단조 조건의 영향 (Effect of Forging Condition on the Microstructure and Mechanical Properties of Centrifugal Casted 9Cr-1Mo Heat-Resisting Steel)

  • 이상명;김윤규;최한글;이정규;조영관;박영태;강창룡
    • 동력기계공학회지
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    • 제14권2호
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    • pp.84-89
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    • 2010
  • The effect of forging condition on the microstructure and mechanical properties of 9Cr-1Mo heat-resisting steel was investigated. Microstructure of centrifugal casted 9Cr-1Mo heat resisting steel and forged heat resisting steel are consisted of martensite. With the increase of forging ratio, tensile strength and hardness increased, while elongation and impact value decreased. By increasing of forging starting temperature and finishing temperature, tensile strength and hardness increased, while elongation and impact value decreased. We obtained the optimum forging conditions as follow, forging ratio is 30%, forging starting temperature is $1200^{\circ}C$ and forging finishing temperature is $950^{\circ}C$.

유한요소해석을 이용한 다축대각단조 시 AA1100합금의 불균일 변형 거동에 관한 모사 (Simulation on Heterogeneous Deformation Behavior of AA1100 During Multi-axial Diagonal Forging Using Finite Element Analysis)

  • 김민성;이성음;이성;정효태;최시훈
    • 소성∙가공
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    • 제28권2호
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    • pp.98-104
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    • 2019
  • The present study numerically simulates the deformation heterogeneity developed in AA1100 during multi-axial diagonal forging (MADF) using finite element analysis (FEA). Diagonal forging type consisting of diagonal forging (DF) and return-diagonal forging (R-DF) proved to be relatively beneficial compared to plane forging type which includes plane forging (PF) and return-plane forging (R-PF) for minimizing the non-uniformity of deformation developed in workpieces. Simulation of the effective strain generated in workpieces during the two types of forging was done using 3-D FEA. FEA shows the effect of friction coefficient on the deformation behavior on workpieces. The simulation of 2 types forging with different friction coefficients revealed that the magnitude of barreling effect and strain heterogeneity in workpieces increases with an increase in the friction coefficient.

Incoloy 825 합금의 기계적 성질에 미치는 열간 단조비와 용체화 온도의 영향 (Effect of Hot Forging Ratio and Solution Treatment Temperature on the Mechanical Properties of Incoloy 825 Alloy)

  • 김도훈;박영태;손영민;강창룡
    • 열처리공학회지
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    • 제31권5호
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    • pp.213-219
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    • 2018
  • This study was carried out to investigate the effect of hot forging ratio and solution treatment temperature on the mechanical properties of incoloy 825 alloy. With an increasing of the hot forging ratio, grain size and range of grain size was decreased. With an increasing of the solution treatment temperature after 90% forging, grain size and range of grain size was increased. Cr carbides and Ti nitrides was precipitated at below $900^{\circ}C$ and volume fraction of precipitate was increased with an decreasing of the solution treatment temperature. With an increasing of the hot forging ratio, hardness, tensile strength and elongation, toughness was increased. With an increasing of the solution treatment temperature after 90% forging, hardness and strength was increased, elongation and toughness was decreased by grain refinement. With an increasing of the forging ratio, effect of solution treatment temperature on the hardness, strength and elongation was small, but on the toughness was large.

변형량 및 변형속도 변화에 따른 Al 6061합금의 특성 변화 (Mechanical Characteristics of Al 6061 Alloy with the Variation of Strain and Forming Speed)

  • 권용남;권진욱;이영선;이정환
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2003년도 춘계학술대회논문집
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    • pp.88-91
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    • 2003
  • The forging of Al 6061 has been studied by using finite element analysis and real forging experiment to find out the effect of strain rate and strain on the final forged product. It seems to be well known that the mechanical properties depend on the microstructures of forged products. The hot deformation of Al alleys including Al 6061 has been researched quite a long period on the various aspects. However, the forging of Al alloys seem to have few information, especially the recrystallization, recovery and grain growth. To elucidate the process variables to control those microstuctual aspects the specially designed model was used for finite element simulation and forging experiments, in which the variation of strain and strain rate could be obtained. The effect of strain md strain rate has been related with the microstructures of forging stocks.

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초 고 탄소 저합금강의 경도와 인성에 미치는 열간단조의 영향 (Effect of Hot Forging on the Hardness and Toughness of Ultra High Carbon Low Alloy Steel)

  • 김종백;강창룡
    • 동력기계공학회지
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    • 제17권6호
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    • pp.115-121
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    • 2013
  • This study was carried out to investigate the effect of hot forging on the hardness and impact value of ultra high carbon low alloy steel. With increasing hot forging ratio, thickness of the network and acicular proeutectoid cementite decreased, and than were broken up into particle shapes, when the forging ratio was 80%, the network and acicular shape of the as-cast state disappeared. Interlamellar spacing and the thickness of eutectoid cementite decreased with increasing forging ratio, and were broken up into particle shapes, which then became spheroidized. With increasing hot forging ratio, hardness, tensile strength, elongation and impact value were not changed up 50%, and then hardness rapidly decreased, while impact value rapidly increased. Hardness and impact value was greatly affected by the disappeared of network and acicular shape of proeutectoid cementite, and became particle shape than thickness reduction of proeutectoid and eutectoid cementite.

주조/단조 공정에서 Al6061의 단조효과에 관한 연구 (Forging Effect of Al6061 in Casting/Forging Process)

  • 권오혁;배원병;조종래
    • 한국정밀공학회지
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    • 제22권11호
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    • pp.45-50
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    • 2005
  • In this study, the casting/forging process was applied in manufacturing a low control arm, in order to prove that application of casting/forging process to Al6061 is likely to get the effect of light weight compared with existing steel products and to reduce the cost of materials. Firstly, In order to set up the optimum casting condition of the forging material, Al6061, casting experiments were carried out by controlling pouring temperature of the aluminum for casting, mold temperature, and pouring time. $700^{\circ}C$ pouring temperature, $300^{\circ}C$ mold temperature and 10-second pouring time were taken into account as the optimum casting conditions. With respect to a hot forging test, it is practiced on the basis of a temperature of materials, strain rate, and reduction rate so as to observe each microstructure and examine strain-stress curve simultaneously; examine tensile test and hardness test; eventually set up the optimum hot forging condition. A hot forging test, tensile test, hardness experiment, and microstructure observation were carried out on condition of $70\%$ reduction rate, $500^{\circ}C$ temperature of materials, and 1 strain rate. As a result of those experiments, 330MPa tensile strength, $16.4\%$ elongation, and 122.8Hv hardness were recorded. In oder to get a sound preform which has no unfitting cavity and less flash, two preforms were proposed on the basis of volume rate of the final product; the optimum volume rate of preform for the low control arm was $115\%$. In conclusion, it is confirmed that using the forging material rather than casting materials in casting/forging process is likely to get more superior mechanical properties. Compared with Al6061, performed by means of general forging, moreover, cast/forged Al6061 can not only stimulate productivity by reducing production processes, but cut down the cost of materials by reusing forging scraps.