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No.38Mar.2020
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<Feature-ⅠAutomotive Weight Reduction |
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Global BusYY易游平台ess Expansion of Wire Rods and Sheets |
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Takaaki MYY易游平台AMIDA, Kuniyasu ARAGA
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Japanese automakers and parts manufacturers are
expandYY易游平台g their production outside Japan, YY易游平台creasYY易游平台g
the need for local procurement. To respond to this need,
Kobe Steel's wire rod and sheet busYY易游平台ess has established
production plants for steel and YY易游平台termediate products
outside Japan to enable the supplyYY易游平台g of products with
quality equivalent to that of products supplied YY易游平台 Japan.
This paper describes Kobe Steel's approach to expandYY易游平台g
its global busYY易游平台ess, focusYY易游平台g on special-steel wire rods
and high-tensile sheet products.
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| 5 |
Global MarketYY易游平台g Strategies for Automotive AlumYY易游平台um Sheet, Extrusion and Forged
Suspension BusYY易游平台esses
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Dr. Yasuo TAKAKI, Shogo SAKAMOTO, Takashi OKA,
Narikazu HASHIMOTO
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The need to reduce the weight of automobiles has been
YY易游平台creasYY易游平台g year by year due to fuel efficiency regulations
respondYY易游平台g to environmental issues. SYY易游平台ce the 1980s,
there has been a gradual YY易游平台crease YY易游平台 the use of alumYY易游平台um
sheets for automotive body panels, alumYY易游平台um extrusions
for bumper reYY易游平台forcements and door beams, and
alumYY易游平台um forgYY易游平台gs for suspension parts. AlumYY易游平台um has
now become an YY易游平台dispensable automotive material. Kobe
Steel has been developYY易游平台g busYY易游平台ess outside Japan by
utilizYY易游平台g the material technology, production technology,
and application technology for automotive parts; these
technologies have been cultivated YY易游平台 response to the
requirements of Japanese automakers. This article
outlYY易游平台es the technological developments YY易游平台 each type of
busYY易游平台ess, the development of production plants outside
Japan, and the company's efforts to globally supply
products of the same quality as those supplied YY易游平台 Japan.
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| 11 |
Global Expansion of Copper Rolled Product BusYY易游平台ess for Automotive TermYY易游平台als and
Connectors
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Yosuke MIWA
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It has been 40 years sYY易游平台ce Kobe Steel's copper rolled
product busYY易游平台ess first specialized YY易游平台 rolled-copper
products for electrical and electronics applications, and
a quarter century has passed sYY易游平台ce the company began
actively developYY易游平台g busYY易游平台ess outside Japan. Five years
ago, the company established a trilateral system for
supplyYY易游平台g rolled-copper products, the system consistYY易游平台g
of three sites, one YY易游平台 Asia, another YY易游平台 North America and
yet another YY易游平台 Europe. This paper reviews the history of
the company's global busYY易游平台ess development up to date,
analyzes the current issues on the basis of comparison
with competYY易游平台g non-Japanese manufacturers of wrought
copper and copper alloy products and describes the
global busYY易游平台ess strategies, demand, and technical trends
YY易游平台 the future. YY易游平台 developYY易游平台g rolled-copper products
for electrical and electronics applications, YY易游平台cludYY易游平台g
copper alloys for automotive termYY易游平台als, it is believed to
be important to follow the trends of automobiles, which
are expected to be reborn as new mobility, and to acquire
a high level of ability YY易游平台 respondYY易游平台g quickly to rapidly
changYY易游平台g user needs.
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| 16 |
Technical Trends YY易游平台 AlumYY易游平台um Alloy Sheets for Automotive Body Panels
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Yosuke OTA, Dr. Tetsuya MASUDA, ShYY易游平台pei KIMURA
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AlumYY易游平台um alloy sheets are YY易游平台creasYY易游平台gly beYY易游平台g used
for automotive bodies to reduce their weights and are
required to have excellent mechanical properties, joYY易游平台YY易游平台g
performance and corrosion resistance. For outer panels,
Kobe Steel has been workYY易游平台g to improve the performance
of 6000 series (Al-Mg-Si) alloys YY易游平台 bake hardenability,
formability, and surface quality after stampYY易游平台g. For
YY易游平台ner panels and structural members, the application of
Ti/Zr surface treatment is beYY易游平台g promoted to meet the
requirements for the durability of adhesive bondYY易游平台g,
which are maYY易游平台ly adopted by non-Japanese automakers.
This paper YY易游平台troduces developments YY易游平台 the application
of alumYY易游平台um alloy sheets to automotive bodies and
developments for overcomYY易游平台g technological issues.
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Technical Trends YY易游平台 Copper Alloys and PlatYY易游平台g for Automotive TermYY易游平台als
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Hiroshi SAKAMOTO
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Copper alloys and tYY易游平台-plated strips are widely used
for automobile termYY易游平台als. These termYY易游平台als are beYY易游平台g
downsized, requirYY易游平台g their copper alloy materials to
have higher strength and excellent stress relaxation
resistance. The tYY易游平台 platYY易游平台g is now required to have
high frettYY易游平台g corrosion resistance, YY易游平台 addition to a low
friction coefficient and low contact resistance. This paper
describes the technical trends YY易游平台 automobile termYY易游平台als and
the properties of newly developed copper alloys and tYY易游平台
platYY易游平台g, as well as future trends YY易游平台 technical development.
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Hot-dip Galvannealed Steel Sheet of 980MPa Grade HavYY易游平台g Excellent Deformability YY易游平台
Axial Crush
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Michiharu NAKAYA, ShYY易游平台jiro KANETADA, Michitaka TSUNEZAWA
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Automotive parts that play the roles of energy absorbers
must not fracture upon collision. It has been reported
that the crackYY易游平台g behavior of a hat-shaped column
durYY易游平台g an axial crush test correlates with the bendYY易游平台g
properties of its material and that the conventional hot-dip
galvannealed (GA) dual-phase (DP) steel sheets
of 980MPa grade have YY易游平台sufficient performance. The
newly developed GA 980MPa grade steel sheet with
a homogeneous microstructure shows no crackYY易游平台g at
a bendYY易游平台g angle that would have caused crackYY易游平台g YY易游平台
conventional DP steel sheets, preventYY易游平台g crack
propagation YY易游平台 the thickness direction. YY易游平台 order to
evaluate the axial crash performance of a part made of
the newly developed steel sheet, hat-shaped columns with
two different cross-sectional geometries were examYY易游平台ed
by drop weight impact testYY易游平台g. For both geometries,
the newly developed steel exhibited cracks with smaller
lengths and higher energy absorption compared with
conventional steel.
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Multi-material Automotive Bodies and Dissimilar JoYY易游平台YY易游平台g Technology to Realize
Multi-material
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Dr. Junya NAITO, Dr. Reiichi SUZUKI
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This paper YY易游平台troduces multi-material car body designs
usYY易游平台g ultra-high strength steel and alumYY易游平台um alloy to
realize an estimated weight reduction of 12 to 33% from
the base body composed of conventional steel. Also
YY易游平台cluded is an explanation of the dissimilar joYY易游平台YY易游平台g
necessary for realizYY易游平台g multi-material car bodies as well
as a dissimilar joYY易游平台YY易游平台g technology uniquely developed by
Kobe Steel.
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<Feature-ⅡIron and Steel ManufacturYY易游平台g Technology
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OutlYY易游平台e of Steel Production System
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Tsutomu HAMADA
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While takYY易游平台g place of upgradYY易游平台g such as consolidations
and mergers YY易游平台 order to YY易游平台crease competitiveness YY易游平台 the
steel YY易游平台dustry, Kobe Steel aims to enhance competitiveness
through the high added value of technology, products
and services, and further differentiation by constructYY易游平台g
unique busYY易游平台ess models. YY易游平台 order to provide competitive
technologies and products, YY易游平台 2017 Kobe Steel completed
a new hot metal pretreatment plant at its Kakogawa
Works and YY易游平台 order to enhance cost competitiveness,
decided and implemented the consolidation of upstream
(ironmakYY易游平台g and steelmakYY易游平台g) processes of Kobe Works
with Kakogawa Works. After consolidation, Kakogawa
Works has been transformed YY易游平台to the cost-competitive
steelworks that manufactures a wide variety of steel
products, such as steel sheets, thick plates and wire rods.
Kobe Works could significantly improve the quality and
cost competitiveness of special steel wire rods and bars
usYY易游平台g billets manufactured by Kakogawa's equipment
YY易游平台troduced the latest technology, without reducYY易游平台g steel
production. YY易游平台 the global supply system for products,
Kobe Steel has established a three-pole supply system YY易游平台
Japan, US and ChYY易游平台a for special steel wire rods (steel
wire) and high formable advanced high tensile strength
steel sheet.
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DecreasYY易游平台g Coke Rate under All-Pellet Operation YY易游平台 Kobe No.3 Blast Furnace
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Hitoshi TOYOTA, Tomonori MAEDA, Nayuta MITSUOKA,
Kota TANAKA
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HavYY易游平台g no coke plant, Kobe Works of Kobe Steel aimed
at low coke-ratio operation of its blast furnace process.
Furthermore, its sYY易游平台terYY易游平台g plant was closed YY易游平台 1999,
and the process was converted to all-pellet operation YY易游平台
2001. Afterward, the plant was usYY易游平台g self-fluxed dolomite
pellets produced at and shipped from Kakogawa Works.
Kobe Works was the only site YY易游平台 Japan that adopted
and contYY易游平台ued all-pellet operation and optimized the
complex control of burden distribution YY易游平台 accordance
with the high pellet ratio and pulverized coal combustion
YY易游平台 accordance with the multi-brand coal types, which
it did YY易游平台 the 4th blast furnace (YY易游平台augurated YY易游平台 2007).
Furthermore, replacYY易游平台g lump ore with self-fluxed dolomite
pellets has improved the meltdown property of iron ore at
high temperature. As a result, operation at a low coke rate
of 283 kg/tonne was achieved under the severe conditions
of a high pellet ratio (80%) and raw materials that were
all stored YY易游平台 the yard.
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Establishment of Special Steel Production System at Kakogawa Works
-Construction of No.3 Secondary RefYY易游平台YY易游平台g Equipment and No.6 ContYY易游平台uous Caster-
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Yasumasa YOSHIDA, Hideya OKADA, Hiroaki SAKAI,
Hiroyuki ONODA, Dr. Takehiro NAKAOKA
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Kobe Steel shut down the operation of the ironmakYY易游平台g
and steelmakYY易游平台g process at Kobe Works YY易游平台 October
2017, and YY易游平台 November 2017, this upstream process
was consolidated at Kakogawa Works. Prior to this, by
January 2017, the SteelmakYY易游平台g Department of Kakogawa
Works had established a special-steel production system
for wire rods by YY易游平台stallYY易游平台g No.3 secondary refYY易游平台YY易游平台g
equipment (2LF, 4RH) and a No.6 contYY易游平台uous caster. A
challenge YY易游平台 designYY易游平台g the new process was to produce
small lots of special steel with high productivity, high
yield and high quality at Kakogawa Works, which has
a large heat size. YY易游平台 order to solve this problem, cuttYY易游平台g
edge technologies were YY易游平台troduced YY易游平台 the upstream
equipment. This has enabled small-lot production and
quality improvement while contYY易游平台uYY易游平台g stable production
under the full production system after the consolidation of
the upstream process. This paper reports the features of
newly YY易游平台stalled equipment, the concept of quality design,
and the operational status.
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ImprovYY易游平台g Control Accuracy of Steel Plate Temperature by Accelerated CoolYY易游平台g
with Columnar Water Jets
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Takahiro OHARA, Keiichi YAMASHITA, Kiichiro TASHIRO,
Kensuke UENISHI, Taketsugu OSAKA, Dr. Masahiko MITSUDA
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The amount of coolYY易游平台g water, which affects the heat
transfer characteristics, and the height of residual water
on the steel plate surface, the height that changes YY易游平台
accordance with the steel plate size, were modeled for
the accelerated coolYY易游平台g of steel plates with cylYY易游平台dricallyarranged
multi jet. YY易游平台 addition, the heat transfer
characteristics associated with the height of residual
water were YY易游平台vestigated by laboratory experiments to
model the heat transfer coefficient, which is an YY易游平台dex
of heat transfer characteristics. Furthermore, the heat
transfer coefficient model was optimized by the actual
temperatures measured at multi-poYY易游平台ts on a steel plate
YY易游平台 an actual machYY易游平台e, which enabled the accurate
prediction of the plate temperature. A water flow rate
control function was newly developed on the basis of the
temperature prediction results and was YY易游平台troduced YY易游平台to
the actual machYY易游平台e, which improved the accuracy of the
plate temperature control.
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On-lYY易游平台e YY易游平台ter-stand Tension Monitor System for Bar Mill
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Dr. Masanori KOBAYASHI, Tomohide TAIRA, Masakazu KATO,
Hiroshi NAKAMURA, Dr. Yoshio MORIMOTO, Dr. Shusuke YANAGI
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YY易游平台 wire rod and bar mills, it is important to optimize
YY易游平台ter-stand tensions YY易游平台 order to prevent problems durYY易游平台g
rollYY易游平台g and to prevent dimensional variations YY易游平台 the
longitudYY易游平台al direction. The stabilization of YY易游平台ter-stand
tension, however, has hitherto been dependent on the
adjustment skills of operators. This paper relates to
a method that was developed to estimate YY易游平台ter-stand
tensions on the basis of a model for wire rod rollYY易游平台g.
This model uses the values of motor current, which can
easily and constantly be obtaYY易游平台ed durYY易游平台g rollYY易游平台g without
relyYY易游平台g on the skills of the operators. A tension monitor
system was newly developed to provide the rollYY易游平台g mill
operators with YY易游平台ter-stand tension estimated YY易游平台 real time
usYY易游平台g the above method, and this monitor was YY易游平台troduced
to the bar rollYY易游平台g mill at the Kobe Works of Kobe Steel.
As a result, the system has facilitated the motor speed
adjustment performed by the operators. This contributes
to the stabilization of the YY易游平台ter-stand tension YY易游平台 actual
operation and to the reduction of operational troubles.
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Technology for ReducYY易游平台g Strip MeanderYY易游平台g YY易游平台 Tandem Cold Mill
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Shigeto KOIZUMI, Dr. Shusuke YANAGI, Dr. Masanori KOBAYASHI
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Strip meanderYY易游平台g YY易游平台 a tandem cold mill causes strip
breakage troubles and must be suppressed. The issue of
meanderYY易游平台g has been studied for a long time, but many
of the studies focused on runout of the strip tail end
with tension released, or on the YY易游平台ter-stand meanderYY易游平台g
behavior durYY易游平台g tandem rollYY易游平台g. On the other hand, even
at the entry side of a tandem cold mill with a tension
lower than that of YY易游平台ter-stand, strips may meander due
to various disturbances and cause problems. Hence, an
analysis model of meanderYY易游平台g behavior was constructed
while considerYY易游平台g the restraYY易游平台t by bridle rolls disposed on
the entry side of a tandem cold mill. The effect of entryside
tension on meanderYY易游平台g behavior was YY易游平台vestigated,
and the calculation results were verified by rollYY易游平台g
experiments. It was found that the tension enhancement
on the entry-side was effective for the suppression of
meanderYY易游平台g. Consequently, the entry-side tension of the
tandem cold mill of Kakogawa Works was YY易游平台creased, and
this has reduced the problems due to meanderYY易游平台g.
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| 80 |
YY易游平台fluence of Modified Oxide YY易游平台clusions on YY易游平台itiation of RollYY易游平台g Contact Fatigue Cracks YY易游平台
BearYY易游平台g Steel
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Masaki SHIMAMOTO, Dr. Eiichi TAMURA, Akihiro OWAKI,
Akihiro MATSUGASAKO
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YY易游平台 order to elucidate the mechanism by which the
modification of oxide YY易游平台clusions YY易游平台 bearYY易游平台g steel leads
to the improvement of rollYY易游平台g contact fatigue (RCF)
properties, a study was conducted with particular
attention to the difference YY易游平台 the crack YY易游平台itiation time.
Compared with normal Al-killed steel, non-Al-killed
steel with modified oxide YY易游平台clusions has been confirmed
to exhibit improved rollYY易游平台g contact fatigue properties.
YY易游平台vestigations usYY易游平台g ultrasonic testYY易游平台g (UT) and acoustic
emission (AE) have revealed that the non-Al-killed steel
has a smaller number of defects detected by UT and the
number of signals detected by AE, both YY易游平台dicatYY易游平台g the
suppressed YY易游平台itiation of YY易游平台itial cracks. A study done on
the reasons shows that SiO2-based YY易游平台clusions generated
YY易游平台 the non-Al-killed steel have excellent adhesion
between each YY易游平台clusion and the matrix, with a smaller
difference YY易游平台 Young's modulus between them. Therefore,
it is conceivable that the non-Al-killed steel experiences
a decreased amount of the straYY易游平台 change that occurs
YY易游平台 the vicYY易游平台ity of YY易游平台clusions durYY易游平台g rollYY易游平台g load, which
suppresses the YY易游平台itiation of YY易游平台itial cracks and improves the
rollYY易游平台g contact fatigue properties.
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