In 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 %.

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標題の順序での工具と材料によって構成される問題の解説を試みるにあたり,まずこの問題が加工において占める位置の認識から入りこもう.それは,課題の潤滑などがの目的に対してどんな意味をもちうるのかを明らかにしておきたいからである.
切削加工では以前から,材料の機械加工性とか被削性という言葉が定義され,広く用いられたが,にも,とにかく性とか成形性とかいう言葉はある.性の定義を機械加工性にならって書くと次の3項目の複合となるであろう.
(1) 破壊することなく永久変形して所望の形状に達する性質.
(2) 工具の寿命を長びかせる性質.
(3) 表面の仕上状態を良好にする性質.
これがの月的に対する材料の適性である.
第1項は,おそらく真の性(tru formability)と言って脚、半であろう.変形を強制された材料が予定の形に達しない前に割れては意味がないし,予定の変形が達せられたかに見えても,工具の強制から解放された材料が,素材原形に復帰するようでも困る.第2項はの研究者の多くが軽視しがちになるが,工具が急速に損耗し頻繁な交換を要するようでは元来の経済性はえられない.第3項は,が部品の粗形をつくり出す範囲を担当する限り重要性をもたないであろう.しかし,板金成形の多くは最終仕上がり製品を目ざしているし,精密な冷間鍛造製品も同様である.将来の熱間鍛造もねらいは精密級製品に置かれるから,寸法誤差と相まって表面の質が改善されなければならない.
ところで,以上のような加工目的と,工具・材料間の問題との連関は次のようである.長年の慣行によって手法基準が確立しているような加工は別として,新規の問題などでは変形を促す工具の刺激が元来どういうものか厳密には予測できないことが多い.それは,工具・材料の接触面直角変位は規定できても,接線変位すなわち工具と材料が接触面に沿う方向にどのような相対変位を行なうかが定まらないからである.だから,この相互作用の理解は工具が材料にもたらす変形刺激の根底をなし,ひいて,工具の摩耗や製品表面の質を定めるものとなる.互いに作用し合う固体の対偶をO.KienzleはWirk-paar(作業対偶)と呼んだが,機械加工の理解はそこで生ずる作業対偶の理解であると言っても過言ではない.本文ではの作業対偶を説明することになる.

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1973年の石油ショックを契機として製造業に対する省資源,省エネルギー,省力,高品質,低コストの要求が一層強まり,更に多種少量生産への対応が迫られるようになった.
は生来これらの要求に応じ得る資質を持っている.たとえば,の原点である自由鍛造や板金叩き出しはハンマと金敷のみで鍋,鍬から花瓶日本刀まで多種多様の製品を作り出すことができた.また,変形拘束の強い工具を使用する現代のでは,製品形状の自由度は失われたが,同一寸法品の生産方式としてほかの加工方法に比べて材料とエネルギーの損失が少ない,生産能率が高い,材質の改善も可能である,などのすぐれた特徴を持つ.精度も向上して研削精度に達した品もある.
今後も工業材料の特性の高度化,用途ならびに利用可能な物質の多用化に対処して,技術は発展して行くであろう.

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The forging has the following features compared with other metal working methods. 1. The surface expansion ratio at the forging is extremely large. 2. The normal pressure at the forging is extremely large. 3. The supply of the lubricant at the forging is difficult. The tribo-simulator for the forging that can take out only the friction energy that shows the feature between the tool and the work of the forging process described now is desired. In this explanation, the behavior of the surface expansion ratio and the normal pressure change in a basic deformation behavior at the forging is summarized. The feature of the tribo-simulator for the forging that has been proposed so far and the result achieved by it are shown, and the way it should be of the tribo-simulator in the future is described.

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水素処理法によって得られたα＋β２相型超微細粒Ti-3Al-2.5V合金(結晶粒径約0.5μm)の超塑性を調べ、さらにこの材料を用いて超法によるクラウンの試作を行った。その結果、超微細粒Ti-3Al-2.5V合金はある温度領域において極めて優れた超塑性伸び(9000%以上)を示すこと、超法によるチタン合金製クラウンの作製は可能であることなどがわかった。

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A 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.

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Workhardable materials like high speed tool steels and super alloys have low ductility and narrow range of temperature suitable for rolling. In the hot profiled rolling of these materials, prevention of cracking in roughing process is significant technique. Considering the strong temperature dependence of deformability, keeping surface of materials high temperature is essential. And relatively homogeneous deformation should be also required. Then thermal mechanical FEM simulations of typical 5 roll pass designs for roughing mill were promoted. The distribution of strain, history of temperature, and mean normal stress at free surface of rolled materials were evaluated. In the view point of surface temperature, square-oval-square method was pointed as the most recommended process. The validity of given results were verified in commercial mass production. The improvement of productivity is supported by the FEM simulation.

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Recently CAE(computer aided engineering) has been spread widely in metal forming. Large model calculation and remeshing in heavy deformation by FE analysis become possible because of the improvements of hardware and software. However the obtained outputs in FE analysis are limited in shape, temperature, various stress and strain. So it is difficult to design optimal process to obtain a final target properties in quantitatively by the current FE analysis system. We have developed digital engineering system DAINUS(DAIdo NUmerical process engineering System) consists of 4 prediction module (1)DAINUS-damage, (2)DAINUS-grain, (3)DAINUS-life, (4)DAINUS-cavity. DAINUS is installed in commercial FE analysis code using user subroutine, and can predict a ductile fracture by DAINUS-damage, micro-structure and mechanical properties by DAINUS-grain, die life by DAINUS-life, cavity consolidation by DAINUS-cavity. Nearly all kind of information in metal forming can be obtained in concretely and in quantitatively by DAINUS. In this paper, the features and abilities are introduced.

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Recently, a warm forging process is remarkable from the points of view in near net shaping and abolishment of additional heat treatment by micro-structural controlling. In generally, a die life in forging decreases accompany with the increase of forging temperature. The die life in hot forging is only about 1/10∼1/100 compared with that in cold forging, because of the serious heat damage. The die life in warm forging is normally about same level of that of hot forging in spite that it is estimated to be about 3∼10 times longer than that in hot forging. There are many important factors such as cooling, lubrication, tool material with high strength and heat resistance, surface treatment, so it is difficult to find out the optimal combination. To solve the above mention problems, we have developed the new Punch Damage Test using parts former for warm forging by use of FE analysis. In this study, we investigated the effects of surface treatments and the kinds of tool steels on die damage in warm forging by the developed Punch Damage Test. And we tried to clarify the mechanism of the die damage by use of FE analysis. The obtained results are following. 1. The wear depends on the depth of plastic flow in hot forging. In order to decrease the wear, it is important to increase of the yield strength of tool steel at elevated temperature, and to apply the surface treatment with high heat resistance. 2. The length and the number of heat cracks increase by applying hard coating, on the other hand hard coating can decrease the length of crack because of defensible boundary between hard coating and base steel. 3. The developed Punch Damage Test is very effective for the evaluation of hard coatings and tool steels in warm forging.

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In order to improve the environments of forming operation, forging manufacturers have recently been switching from the graphitic water or oil-based lubricants to the non-graphitic water-based lubricants. When such lubricants are employed, however, shorter die life and poor metal flow into the cavity is observed, which leads to poor efficiency of operation.
Boron nitride has the lamellar structure similar to graphite. Therefore, lubricant performances of non-graphitic water-based lubricants including boron nitride were evaluated by the ring compression test and the spike test in the hot forging temperature range, and the following results were obtained:
(1) The friction shear factor for non-graphitic water-based lubricants with 1% addition of boron nitride decreased in ring compression test.
(2) Some non-graphitic water-based lubricants showed better performance of lubricity than that of graphite in the spike test. However, they required higher forging loads than that of graphite, resulting in the decrease of die life.
(3) Non-graphitic water-based hot forging lubricants compounded of several calboxylic acids showed an improvement of close adherence between die-material surface compared to that of a single calboxylic acid.
(4) Calboxylic acids gave a better stabilized perfomance at 1373K by inclusion of boron nitride.

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Recently, 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.

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