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Volume 76 (2005)
- Issue 4 Pages 229-
- Issue 3 Pages 159-
- Issue 2 Pages 79-
- Issue 1 Pages 5-
Volume 76, Issue 2
Displaying 1-8 of 8 articles from this issue
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Shigekazu Ito, Hiroaki Yoshida, Sachihiro Isogawa2005 Volume 76 Issue 2 Pages 79-86
Published: April 28, 2005
Released on J-STAGE: April 19, 2010
JOURNAL FREE ACCESSA lubricant plays an important part in forging, which can reduce forging load and make knockout smoothly. Ring compression test or spike test have been well used as standard evaluation methods of lubricants. However, forging conditions of parts such as flange bolt and CVJ components are much severe than those of spike test or ring compression test. So the development of more sever evaluation method of the lubricants has been desired strongly. We have developed new evaluation test by backward extrusion with taper punch. The new test named "Taper cup test" can evaluate lubrication under large deformation, which are twice ∼4 times as large as that of spike test. In this test, surface expansion ratio can be controlled by changing the punch stroke, and it is possible to know the forging limit of the lubricant by measuring the changing point of the forging load.View full abstractDownload PDF (197K) -
Nobukazu Hirano, Masanao Fujiwara, Hiroaki Yoshida, Sachihiro Isogawa2005 Volume 76 Issue 2 Pages 87-94
Published: April 28, 2005
Released on J-STAGE: April 19, 2010
JOURNAL FREE ACCESSIn the ferritic stainless steel, such as SUS430, grain refinement is one of the useful measures to improve the strength and the toughness. So it is important to optimize the rolling schedule as rough process of production with the view of grain refinement. In optimization of the rolling schedule, microstructural prediction by computer simulation is one of the most important elemental technologies from the viewpoint of cost reduction and superior quality. In this study, microstructural prediction technology for SUS430 has been developed to optimize the rolling schedule for grain refinement. And trial production in actual multi-stage mill has done to test accuracy of prediction.
Obtained results are as follows.
1. It became possible to predict microstructure on multi-stage rolling by application of incremental microstructure prediction method.
2. This system is useful for microstructure prediction on multi-stage rolling within adequate preciseness.
3. On designed rolling schedule wit t using microstructural prediction system, mean grain size of center in wire has been reduced about 36 %.View full abstractDownload PDF (205K) -
Takuma Okajima, Hiroaki Yoshida, Sachihiro Isogawa2005 Volume 76 Issue 2 Pages 95-102
Published: April 28, 2005
Released on J-STAGE: April 19, 2010
JOURNAL FREE ACCESSRecently, warm forging process takes the place of hot forging process gradually, for example, in manufacturing CVJ. However, die damage is serious problem in warm forging process with large expansion of surface of work piece, because it is not inquired enough. Though trying to extend die life by means of FEM analysis, it dose not play an enough role, because there is few method to evaluate die damage in warm forging condition. The test of Pin-on-disk and Ogoshi wear out can not be also applied to the method of die damage of warm forging process.
In this study, we have established new test which could systematically evaluate die damage in warm forging process. And we have examined forging condition in warm forging process about quality of die and cooling system of die. This test aims at utilizing for establishment of simulation engineering of die damage prediction and quantitative evaluation method.View full abstractDownload PDF (294K)
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Takashi Ishikawa2005 Volume 76 Issue 2 Pages 103-112
Published: April 28, 2005
Released on J-STAGE: April 19, 2010
JOURNAL FREE ACCESSSurface micro-defects affect surface quality and cause breakdown and cracks in rolled products. Many efforts have been made to prevent the occurrence of micro-defects in rolling plants, however, producing defect-free products remains very difficult. Many kinds of surface defects occur in rolling processes. The shapes of surface defects after rolling change in various manners, depending on the rolling conditions. Determining the relation between the shape of surface defect before rolling and that after rolling may lead to an effective method for predicting the occurrence of a surface defect and development of a process to eliminate defects. This review is focus on the numerical approach to predict surface micro-defects in rolling.View full abstractDownload PDF (306K) -
Kenji Higashi2005 Volume 76 Issue 2 Pages 113-124
Published: April 28, 2005
Released on J-STAGE: April 19, 2010
JOURNAL FREE ACCESSAs the desire to further utilize lightweight magnesium alloys in various industrial applications grows, different aspects of magnesium research must be intensified in order to improve various properties of magnesium alloys and enhance their chances of being selected by the product designers. In the current four-year term project on the Platform Science and Technology for Advanced Magnesium Alloys, the research fields related to all the magnesium alloys have been focused to the selected three categories: ecomaterials design and processing, high qualification of mechanical performance, and high performance design and processing in functionality. Each research group is introduced together with its strategic directions toward future R & D for advanced magnesium alloys. Each group has its own joint research network to drive new research directions. Academic and industrial importance is stressed as a fruitful result of the present project. The paper generally overviews the interesting results obtainnd in our laboratory for the expanding development and industrial applications of magnesium alloys and related technologies. Furthermore, research efforts aimed at increasing the future applications of magnesium alloys, particularly in the electronics and automobile industries are presented. The research trend shows that industrial applications of magnesium alloys, which have gained momentum in recent times, have a bright future in Japan. Generally the research efforts are yielding positive results and it is expected that various industries will begin to apply some of the newly developed alloys and processes to new products that will help to reduce social and environmental problems as envisioned by widespread utilization of magnesium alloys.View full abstractDownload PDF (377K) -
Shinichiro Fujikawa2005 Volume 76 Issue 2 Pages 125-134
Published: April 28, 2005
Released on J-STAGE: April 19, 2010
JOURNAL FREE ACCESSRecently, CAE analyses have been commonly applied to many forging die longevity problems. The typical die life patterns are fracture and wear. The type, "fracture or wear?", is easily identified by using Weibull analysis, one of reliability analysis methods. The review introduces the CAE application examples for both of forging die fracture and wear problems. The first example is stress analysis for the side flange dies. The countermeasure to reduce the highest stress on the forging die surface was easily obtained by CAE. The second example is wear analysis for front wheel hub dies. The formulation regarding die wear that the author established enabled wear analysis by using FEM to reduce the die wear. The review concludes the standard ways to improve the forging die longevity.View full abstractDownload PDF (252K)
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Kazuhito Hattori, Kouji Nozue, Masakatsu Yamakawa, Takashi Ishizawa, M ...2005 Volume 76 Issue 2 Pages 135-140
Published: April 28, 2005
Released on J-STAGE: April 19, 2010
JOURNAL FREE ACCESSSUS630 is a martensitic precipitation hardened stainless steel having high strength and the good corrosion resistance comparable with SUS304, and used as stern shaft, high strength bolts, and the golf club faces, etc. In golf club faces, thickness of face steel had been 2.3 mm or more to secure durability. To obtain better "Carry" and "Impact feeling" by nonconventional high restitution face, thickness of the face was expected to be possible by thinning by 2.0 mm or less. However, to thin the thickness of the face, a strong material was necessary to secure durability, and application of ausforming process for SUS630 was proposed. Through ausforming process for SUS630 in forging test, tensile strength was closed to 1500 MPa because of the effect of ausforming. To mass-produce the ausformed SUS630, hot rolling process through ausforming was selected from the point of view in production cost, production variation, and constraint on machine. Ausforming process in finish rolling with application of 80 % high reduction in rough rolling with a view of strengthening and more toughness by refining austenitic grain size, named as Combined Ausforming Process (C-AF), was specified on hot rolling process, and hardness has achieved from 480HV to 510HV after aging treatment. Strengthening of SUS630 with C-AF rolling process made it possible to be adopted as golf club face material with high restitution by thinning thickness by 2.0 mm or less.View full abstractDownload PDF (136K) -
Jun-ichi Esaki2005 Volume 76 Issue 2 Pages 141-146
Published: April 28, 2005
Released on J-STAGE: April 19, 2010
JOURNAL FREE ACCESSDisk-shaped forging parts have been used for a power generation gas turbine and an airplane jet engine. High strength and durability are required for the disks. Therefore, the fine grain and homogenious grain distribution in the disks are very important. Daido Steel has developed a rotatory disk forging method in order to obtain fine and homogenious microstructure. This method has the feature that there is few dead metal region. However, a rotatory disk forging has many parameters which must be controlled. In order to solve the problems, a process modeling system has been developed and optimized forging process has been obtained as follows:
(1) The material database of INCONEL718 was built. And the axsymmetric model and 3-dimensional full model of a rotatory disk forging were created. Various information which includes the grain size inside a disk by this came to be acquired.
(2) It was shown that a rotatory disk forging is effective in equalization of grain size in a disk.View full abstractDownload PDF (150K)
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