• Title, Summary, Keyword: Ceramic Art

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Stellite bearings for liquid Zn-/Al-Systems with advanced chemical and physical properties by Mechanical Alloying and Standard-PM-Route

  • Zoz, H.;Benz, H.U.;Huettebraeucker, K.;Furken, L.;Ren, H.;Reichardt, R.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.9-10
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    • 2000
  • An important business-field of world-wide steel-industry is the coating of thin metal-sheets with zinc, zinc-aluminum and aluminum based materials. These products mostly go into automotive industry. in particular for the car-body. into building and construction industry as well as household appliances. Due to mass-production, the processing is done in large continuously operating plants where the mostly cold-rolled metal-strip as the substrate is handled in coils up to 40 tons unwind before and rolled up again after passing the processing plant which includes cleaning, annealing, hot-dip galvanizing / aluminizing and chemical treatment. In the liquid Zn, Zn-AI, AI-Zn and AI-Si bathes a combined action of corrosion and wear under high temperature and high stress onto the transfer components (rolls) accounts for major economic losses. Most critical here are the bearing systems of these rolls operating in the liquid system. Rolls in liquid system can not be avoided as they are needed to transfer the steel-strip into and out of the crucible. Since several years, ceramic roller bearings are tested here [1.2], however, in particular due to uncontrollable Slag-impurities within the hot bath [3], slide bearings are still expected to be of a higher potential [4]. The today's state of the art is the application of slide bearings based on Stellite\ulcorneragainst Stellite which is in general a 50-60 wt% Co-matrix with incorporated Cr- and W-carbides and other composites. Indeed Stellite is used as the bearing-material as of it's chemical properties (does not go into solution), the physical properties in particular with poor lubricating properties are not satisfying at all. To increase the Sliding behavior in the bearing system, about 0.15-0.2 wt% of lead has been added into the hot-bath in the past. Due to environmental regulations. this had to be reduced dramatically_ This together with the heavily increasing production rates expressed by increased velocity of the substrate-steel-band up to 200 m/min and increased tractate power up to 10 tons in modern plants. leads to life times of the bearings of a few up to several days only. To improve this situation. the Mechanical Alloying (MA) TeChnique [] is used to prOduce advanced Stellite-based bearing materials. A lubricating phase is introduced into Stellite-powder-material by MA, the composite-powder-particles are coated by High Energy Milling (HEM) in order to produce bearing-bushes of approximately 12 kg by Sintering, Liquid Phase Sintering (LPS) and Hot Isostatic Pressing (HIP). The chemical and physical behavior of samples as well as the bearing systems in the hot galvanizing / aluminizing plant are discussed. DependenCies like lubricant material and composite, LPS-binder and composite, particle shape and PM-route with respect to achievable density. (temperature--) shock-reSistibility and corrosive-wear behavior will be described. The materials are characterized by particle size analysis (laser diffraction), scanning electron microscopy and X-ray diffraction. corrosive-wear behavior is determined using a special cylinder-in-bush apparatus (CIBA) as well as field-test in real production condition. Part I of this work describes the initial testing phase where different sample materials are produced, characterized, consolidated and tested in the CIBA under a common AI-Zn-system. The results are discussed and the material-system for the large components to be produced for the field test in real production condition is decided. Outlook: Part II of this work will describe the field test in a hot-dip-galvanizing/aluminizing plant of the mechanically alloyed bearing bushes under aluminum-rich liquid metal. Alter testing, the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed. Part III of this project will describe a second initial testing phase where the won results of part 1+11 will be transferred to the AI-Si system. Part IV of this project will describe the field test in a hot-dip-aluminizing plant of the mechanically alloyed bearing bushes under aluminum liquid metal. After testing. the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed.

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A Study on the "Holing-Bowl(받침그릇, 承盤) for the Jung-Byoung(정병, 淨甁)" or The Sacred Water-pot (정병 받침그릇(淨甁 承盤) 살핌 -고려불화(佛畵)-수월관음그림(水月觀音圖)으로 -)

  • Ghang, soon-hyoung
    • MUNHWAJAE Korean Journal of Cultural Heritage Studies
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    • v.34
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    • pp.124-136
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    • 2001
  • Among many different types of wares, we have amazing Sacred Water-pot(따르개, 注子) from Goryo-period(고리, 高麗, 918-1392). The stylistic peculiarity of Jung-Byoung(정병, 淨甁) is described in "Goryo-Dhogyoung, 고리도경, 高麗圖經", the classical design canon. It is said, "A sharpened mouth with narrow and prolonged neck is attached upon the broad mouth with thicker and even longer neck of the pot whose body intimates to the shape of melon." One could find this Jung-Byoung similar to the Indian drinking water jar, Kundika, which has been. even today, an everyday article in houses as well as in temples. In the early Buddhist cult, the object had been adopted as personal belonging of the Bodhisattvas(보살, 菩薩), especially of the Bodhisattva Avalokitesvara(관세음보살,觀世音菩薩). In short, the purifying character of water is met by the sacred ware to deliver the refreshing Sweet-Water(Holy-Water, 깨맑물, 단물, 단이슬물, 정수, 감로, 감로수, 성수, 淨水, 甘露, 甘露水, 聖水): For the holy purpose of fulfilling the thirst of people, of symbolozing the virtuous dharma. Thus, Ggamslkh-Byoung(깨맑병,淨水), the literal Korean name, denotes purifying and clarifying and clarifying water-pot to us. Among many other Asian countries, India, China, Korea, and Japan have a profound cult of the sacred water-pot(Ggamalkh-Byoung, Jung-Byoung, 깨맑병, 정병, 정수병, 감로병, 감로수병, 淨甁, 淨水甁, 甘露甁, 甘露水甁). Therefore, this charming holy object drew much attention not only from master artisans to shape and deliver them to people but also from painters and sculptors for their endowment of the sacred images dedicated to Buddha(부처,佛,佛陀). In China, the sacred water pot emerged in the period of Tang(당, 唐, 618~907)-Period and underwent much sophistication later on, I. e., from earthenware, ceramic-porcelain, bronze, and silver. However, the following represents a challenge to the well-known Goryo-Thangka(고리불화, 高麗佛畵) Painting of Bodhisattva Avalokitesvara to our speculation on the Sacred Water-pot(정병, 淨甁). The image suggests, when examined closely, that the Sacred Water-pot has been accompanied by, or placed in, a transparent glasswere(유리그릇) or crystalbowl(수정그릇)! We have no other physical proof of the existence of such a Holding-Bowl(받침그릇, 承盤), except for in this particular painting. This Holding-Bowl would have not been a mere elaboration on the practicality of controling the drips from the mouth of the pot. As in the chapter on Tang-ho(탕호, 湯壺), or thermal bowl, in the "Goryo-Dhogyoung" it advises readers that this style of bowl is to be filled with hot water, and thus function as a preserver of heat in the water inside the pot. As an offering to the Buddha, the Sacred Water-pot could have been used for serving him hot tea. Hence the sacred bottle is to contain the refreshing water, the water transcends to nectar, and the nectar is prepared as a nectar tea to offer the Buddha. For both the Holding-Bowl of Ggamalkh-Byoung(Jung-Byoung)and the Celestial-Robe(날개옷, 天衣) of the Bodhisattva Avalokitesvara, whose specified character is the Water-Moon(수월, 水月) in this particular Thangka(불화, 佛畵) painting, the transparency is essential. This is to refer to the purity and the lucid clarity of Bodhisattva Avalokitesvara and at a deeper level, to refer to the world of Buddhas-the Tushita(Paradise, Heaven, Eden, 극락, 불세계, 極樂, 佛世界). Howerver, without the discovery of an actual Holding-Bowl, accompanied by a Sacred Water-pot, such speculation will necessarily remain hypothetical. Nevertheless, there is an abundance of evidence of our ancient craftsmanship in jade and ctystal, dating back to the Bronze Age(1000~2B.C.) in Korea. By the time of the Three Kingdom-Period(삼국시대, 三國時代, 57B.C.~935A.D.), and especially the Silla(신라, 新羅, 57B.C.~935A.D.)-Empire, the jade and crystal ornamentation had become very intricate indeed. By the Goryo-Period(918~1392) and Chosun-Period(조선, 朝鮮,1392~1910),crystal-ware and jade art were popular in houses and Buddhist temples, whose master artsanship was heightened in the numerous Sarira-Cases(사리그릇, 舍利器), containing relics and placed inside Stupas(탑, 투, 搭)! Therefore, discovering a tiny part of the crystal or jade Holding-Bowl for the Sacred Water-pot and casting full light on this subject, would not be totally impossible. Lastly the present article shares the tiny hope for a sudden emergence of such a Holding-Bowl.