Effect of Forging Type on the Deformation Heterogeneities in Multi‑Axial Diagonal Forged AA1100

Min‑Seong Kim,Sang‑Chul Kwon,Sun‑Tae Kim,Seong Lee,Hyo‑Tae Jeong,Shi‑Hoon Choi 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.3

The present study investigated the effects that different types of forging exert on the deformation heterogeneities developedin AA1100 during multi-axial diagonal forging. To measure the deformation heterogeneities of deformed workpieces, thevalues for hardness and Kernel average misorientation were measured at the center section following each forging process. Type-D forging that consists of diagonal forging and return-diagonal forging was relatively advantageous compared withType-P forging that includes plane forging and return-plane forging for minimizing the non-uniformity of deformationdeveloped in workpieces. The effective strain developed in a workpiece during the 2 types of forging was simulated using3-D FEA. FEA revealed that the positions and degrees of occurrence for soft and hard-zones in workpieces vary greatlydepending on the forging type. Type-D forging was relatively advantageous compared with Type-P forging for minimizingthe non-uniformity of effective strain developed in workpieces.

Hot Shape Forging of Gas Turbine Disk Using Microstructure Prediction and Finite Element Analysis

차도진,김동권,조종래,배원병 한국정밀공학회 2011 International Journal of Precision Engineering and Vol. No.

The Waspaloy, a Ni-based superalloy, has been widely used for forging material of gas turbine disk since it requires the high tensile strength at high temperature and good resistance to low cycle fatigue. The purpose of this study is to develop a forging process of turbine disk that satisfies the hot deformation characteristics of Waspaloy. Generally, the hot forging of superalloy has been subjected to isothermal forging since the available temperature range of forging is narrow. However,the non-isothermal forging was used to make a turbine disk in this study. Therefore, the analyses of temperature variation and deformation behavior of the material were important to obtain the sound forging products. The hot compression test was carried out to know formability at high temperature and microstructure evolution during hot deformation. In order to define the optimum forging conditions including material temperature, strain rate, strain, microstructure evolution and forging load, the commercial finite element analysis code was used to simulate the forging procedure of turbine disk. The hot forged turbine disk was heat-treated for obtaining the high temperature properties. The cut-off tests on the heat-treated forged disks were carried out. Experimental results were compared with the simulation results by FE analysis. Test results were in good agreement with the simulations. This study shows that the superalloy turbine disk can be manufactured by the semi-closed die forging.

Hot Shape Forging of Gas Turbine Disk Using Microstructure Prediction and Finite Element Analysis

Cha, Do-Jin,Kim, Dong-Kwon,Cho, Jong-Rae,Bae, Won-Byong 한국정밀공학회 2011 International Journal of Precision Engineering and Vol.12 No.2

The Waspaloy, a Ni-based superalloy, has been widely used for forging material of gas turbine disk since it requires the high tensile strength at high temperature and good resistance to low cycle fatigue. The purpose of this study is to develop a forging process of turbine disk that satisfies the hot deformation characteristics of Waspaloy. Generally, the hot forging of superalloy has been subjected to isothermal forging since the available temperature range of forging is narrow. However, the non-isothermal forging was used to make a turbine disk in this study. Therefore, the analyses of temperature variation and deformation behavior of the material were important to obtain the sound forging products. The hot compression test was carried out to know formability at high temperature and microstructure evolution during hot deformation. In order to define the optimum forging conditions including material temperature, strain rate, strain, microstructure evolution and forging load, the commercial finite element analysis code was used to simulate the forging procedure of turbine disk. The hot forged turbine disk was heat-treated for obtaining the high temperature properties. The cut-off tests on the heat-treated forged disks were carried out. Experimental results were compared with the simulation results by FE analysis. Test results were in good agreement with the simulations. This study shows that the superalloy turbine disk can be manufactured by the semi-closed die forging.

복합단조 공정을 적용한 Outer Support Ring 개발

주원홍(Won Hong Ju),박성영(Sung-young Park) 한국산학기술학회 2017 한국산학기술학회논문지 Vol.18 No.4

본 연구에서는 원웨이 클러치의 핵심 부품인 Outer Support Ring의 복합 단조 공정을 개발하고, 시제품을 제작하여 평가하였다. 기존 공정 즉, 열간 단조와 MCT 가공 공정은 과대한 소재 절삭량과 가공 시간이 길다는 단점이 있다. 이를 극복하고자 열간 단조를 통하여 형상을 구현하고, 냉간 단조를 통하여 정밀한 부품을 성형하였다. 최소한의 가공만을 적용하는 복합 단조 공정을 개발하였다. 상용 소프트웨어인 Deform-3D를 이용하여 단조 해석을 수행하였다. 해석 결과를 바탕으로 열간 단조 및 냉간 단조 공정을 설계하였고, 실제 금형 및 시제품을 제작하였다. 제작한 시제품은 경도, 표면 조도, 내부 결함, 단류선 검사 등의 평가를 수행하였다. 평가결과 특이한 문제점은 발견되지 않았으며, 양산적용이 가능할 것으로 판단된다. 복합 단조를 통하여 열간 단조와 MCT 가공 공정 대비 약 27%의 소재를 절감할 수 있었다. 또한 제품 개당 생산 시간은 약 2.15배 단축되었다. 본 연구를 통하여 원가 절감이 가능한 공정 및 금형 설계 기술을 확립하였고, 이를 통하여 관련 자동차 부품 생산에도 긍정적인 효과가 있을 것으로 기대된다. In this study, the complex forging process of an outer support ring was developed and the prototype was manufactured. The current process, hot forging and MCT machining, has a disadvantage of excessive material removal rates and longer machining hours. To overcome this disadvantage, a general shape is given through hot forging and the precision is achieved through cold forging. The complex forging process was developed with the minimal machining process. Forging analysis was carried out to design a forging process using the commercial program, Deform-3D. The hot and cold forging processes were set up based on the analyzed result. The mold and prototype were manufactured. Hardness, surface roughness, internal defect, the grain low line of the prototype were evaluated. The results showed no particular problems, and there were no problems in mass production. Using complex forging, the material was reduced by approximately 27 % compared to the process using hot forging and MCT machining. In addition, the production speed was improved 2.15 fold compared to that of hot forging and MCT machining. Through this study, a cost-effective process and mold design technology were established, which is expected to have positive effects on other related automotive parts production.

Al 6061-T6 단조 성형품의 기계적 특성

박철,김상식,권용남,이영선,이정환,Park, C.,Kim, S.S.,Kwon, Y.N.,Lee, Y.S.,Lee, J.H. 한국재료학회 2003 한국재료학회지 Vol.13 No.6

The effect of forging parameters, including different forging stock, strain rate and strain, on the mechanical properties of hot-forged Al 6061-T6 was investigated. The forging was conducted using either hydraulic press, crank press or hammer press, respectively, at a forging temperature of $400^{\circ}C$. When using an extruded bar as a forging stock, the tensile strength was lower for the specimens prepared by hammer forging than those by crank press forging. It was found that the coarsening of recrystallized grain was responsible for the decrease in tensile strength with hammer forging. Systematic studies on the effects of strain and strain rate on the tensile properties of hot-forged Al 6061-T6 products using extruded bar as a forging stock further suggested that the coarsening of recrystallized grains and$ Mg_2$Si precipitates complexed the observed trends in the tensile behavior. In case of hot forging with continuous cast bar as a forging stock, on the other hand, the mechanical properties of the specimen were largely improved with hammer press compared to those with crank press, which appeared to be due to the homogenization of microstructure.

합금강을 이용한 스퍼기어의 정밀 냉간 단조

최재찬,최영 釜山大學校生産技術硏究所 1998 生産技術硏究所論文集 Vol.55 No.-

The conventional closed-die forgings had been applied to the forging of spur gears. But the forgings require high forging-pressure. In this paper, new precision forging technology have been developed. The developed technology is two steps forging process. Good shaped products are forged successfully with lower forging-pressure than those of conventional forging. The accuracy of the forged spur gear obtained by new precision forging technology is set nearly equal to that of cut spur gear of foruth and fifth class in Korean industrial standard

Process analysis of multistage forging by using finite element method

Park, K.S.,VanTyne, Chester J.,Moon, Y.H. Elsevier 2007 Journal of materials processing technology Vol. No.

<P><B>Abstract</B></P><P>Much progress in forging technology including low production cost and fast production has allowed an intensive use of forging. Manufacturing companies have especially focused on producing a complex shaped part with a tight dimensional tolerance. Traditional warm and cold forging methods have their own limitations to produce such a complex shaped part; warm forging requires complex system with relatively higher manufacturing cost, while cold forging is not applicable to materials with limited formability. Therefore, multistage forging may be advantageous to produce complex shaped parts. In order to build a multistage forging system, it is necessary to characterize mechanical properties in response to system design parameters such as temperature, forging speed and reduction. For the analysis of formability of multistage forging process, finite element method (FEM) has been used for the process analysis. As a model case, a constant velocity (CV) joint forging process is analyzed by FEM, since CV joint has a complex shape and also its required dimensional tolerances are very tight. A systematic approach to process analysis is established using the FEM for the multistage forging of the CV joint outer race.</P>

정밀냉간단조 기술을 적용한 자동차 액추에이터용 스퍼기어 부품개발

박동환,한성철 한국소성∙가공학회 2023 소성가공 : 한국소성가공학회지 Vol.32 No.6

Spur Gear parts for automobile actuators using existing former forging technology were produced in a total of three processes on a former forging machine. However, in order to improve cost increase due to frequent mold breakage, Spur Gear parts were designed and manufactured in the cold forging process after forming the preform through former forging. In other words, in the existing former forging mold, product seating defects occurred due to horizontal movement, resulting in many product defects and mold damage, so there was an urgent need to improve mold life and product defects. In order to improve this, we tried to improve the mold life by improving the existing 3 former forging processes to a former forging process and 2 cold forging processes. Therefore, We developed Spur Gear parts for automobile actuators were developed by applying precision cold forging technology through a former forging process and 2 cold forging processes to improve mold life.

열간자유단조와 링롤링공법을 이용한 풍력발전기용 도아프레임 개발

권용철(Yong Chul Kwon),강종훈(Jong Hun Kang),김상식(Sang Sik Kim) 대한기계학회 2015 大韓機械學會論文集A Vol.39 No.7

풍력 발전기용 기계부품은 주로 자유단조 공법을 통하여 제조된다. 본 연구는 풍력발전기용 타워 부품인 도아프레임의 제조하기 위한 발전된 단조공법에 관한 연구이다. 개발된 단조공법의 장점은 원소재 회수율을 높임에 따라 원소재 투입량을 줄임으로 제조원가를 낮춘다. 기존의 단조공업은 유압프레스를 이용하여 단조작업이 이루어지며 최종제품과 단조품의 형상 차이로인하여 많은 부분이 가공으로 제거된다. 하지만 제안된 단조공법은 열간 자유단조와 링롤링공법을 통하여 원소재 회수율을 높이게 된다. 새로운 공법의 유효성은 링롤링 블랭크의 치수와 밀접한 관련이 있기 때문에 유한요소해석을 통하여 블랭크의 치수를 최적화 하였다. 유한요소해석을 통하여 얻은 단조품의 치수는 시제품 생산을 통하여 검증하였다. The mechanical components for wind turbines are mainly manufactured using open-die forging. This research introduces an advanced forging method to produce the door frame of the tubular wind turbine tower. The advantages of this new forging method are an increase in the raw material utilization ratio and a reduction in energy cost . In the conventional method, the door frame is hot forged with a hydraulic press and amounts of material are machined out because of the shape difference between the forged and final machine products. The proposed forging method is composed of hot forging and ring rolling processes to increase the material utilization ratio. The effectiveness of this new forging method is deeply related to the ring rolled blank dimension before the final forging. To get the optimal ring rolled blank, forged shape prediction using the finite element analysis method was applied. The forged dimensions produced by the new forging method were verified through the first article production.

중공 잉곳을 이용한 대형 링 단조공정 설계 연구

이영선(Y. S. Lee),이명원(M. W. Lee),이승욱(S. W. Lee),이동희(D. H. Lee),김상식(S. S. Kim) 한국소성가공학회 2010 한국소성가공학회 학술대회 논문집 Vol.2010 No.5

Ring forging process is more appropriate for high-length and thin walled ring, because it utilizes the forging press and hence does not require heavy-duty ring rolling mill. Although ring forging process is very simple and economic for facilities, the process is not efficient because of multi-forging-step and low material utilization. An effective ring forging process is developed using a hollow ingot. When a hollow ingot is used with a workpiece, the ingot can be forged into a final ring without multi-stage pre-forging process, such as, cogging, upsetting, and piercing, etc.. Finally it has advantages of the material utilization and process improvement because few reheating and forging process are not necessary to make workpiece for ring forging. The important design variables are applied plastic deformation energy to eliminate cast structure and make uniform properties. In this study, the mechanical properties of forged shell were investigated by the experiment using sectional model and also the process conditions were designed by Fern simulation.