 |
 |
 |
 |
No. 36 NOV. 2018
|
|
|
<Feature-Ⅰ>Welding and Joining Technology |
|
|
| 1 |
Flux-cored Wire for HT610 Class Steel Showing
Excellent Toughness after PWHT
|
|
|
|
Dr. Yoshihiko KITAGAWA, Shuji SASAKURA, Masahiro INOMOTO,
Hidenori NAKO, Yoshitomi OKAZAKI
|
|
|
A detailed study has been conducted to improve notch
toughness after post weld heat treatment (PWHT) of
weld metal made from flux-cored wires for steel with a
tensile strength of 610 MPa class. The microstructure
and carbide morphology after PWHT at 620℃ were
examined. The results have revealed that the size of
cementite particles precipitating along the prior austenite
grain boundaries significantly affects the toughness.
Presumably, this was caused by the cementite precipitates
acting as the initiation sites of grain boundary fracture.
To refine the cementite precipitates on grain boundaries,
it has been found to be effective to adjust the content
of C, as well as that of Cr and/or Mo, carbide forming
elements. This study has resulted in a weld metal with an
optimal composition for HT610 class steel, the weld metal
having an excellent strength after PWHT and toughness at
-40℃.
|
|
| 7 |
Welding Process Using Special Torch for Reducing
Diffusible Hydrogen
|
|
|
|
Naoki MUKAI, Dr. Reiichi SUZUKI
|
|
|
Diffusible hydrogen is an important factor in cold
cracking, and the lower its content, the better. This study
contains a discussion and analysis of the behavior of
hydrogen sources in metal active gas (MAG) welding
consumables (hereinafter, "welding wires") to devise and
develop a new process for reducing diffusible hydrogen,
a process for suctioning and discharging the hydrogen
sources desorbed from welding wires. Evaluation of the
effectiveness of the new process has confirmed that it
renders harmless the influence of surface lubricant and
moisture absorbed after production and is effective as a
new technique for reducing hydrogen. The subject welding
wires include both solid wires and flux-cored wires
(FCW). In the case of the latter, the moisture initially
contained in the flux has been significantly reduced for
seamed FCW: the effect, however, is less significant for
seamless FCW. The present process has been found to be
particularly effective when combined with seamed FCW.
|
|
| 17 |
Robotic Welding System for Shipbuilding
|
|
|
|
Kenji SADAHIRO, Shuhei HONDA, Shunsuke MIYATA, Yutaku SHO,
Naoya SAWAGUCHI, Kazuyuki KIKUCHI
|
|
|
As a world-leading welding solution company, Kobe
Steel began working on the automation of shipbuilding. A
robotic welding system has been developed to be applied
to the assembling processes in shipyards. The system
includes a robot controller compatible with the small
robot that enters hull blocks, a robot carrier for moving
within blocks, and robot-program-preparation software
allowing offline teaching using 3D models. This paper
introduces our robotic welding system offering welding
solutions, which integrates all the elements, including
the development of optimum welding wires and welding
techniques such as gap filling.
|
|
| 23 |
Features of New Robot Controller, CB-type Controller,
for ARCMAN™ Welding System
|
|
|
|
Takeshi KOIKE, Shuichi INADA, Atsushi FUKUNAGA, Naoki KIDA,
Tsutomu ONE
|
|
|
Recently, the needs for welding automation have
become more diversified and advanced, requiring a
robot controller with higher performance and improved
functions. Hence, we have developed a new controller,
the CB-type controller, which features high performance,
highly-sophisticated functions, and ease of use. This
paper introduces these three features. In addition, the
potential of the CB-type controller is described along with
the example of a new arc-sensor control system under
development.
|
|
| 28 |
New Arc-welding Robots
|
|
|
|
Tatsuji MINATO, Taichi IGARASHI, Motoaki MURAKAMI,
Takashi WADA
|
|
|
A series of arc-welding robots, the ARCMAN™ series,
comes in sizes suitable for various welding objects, and
many have been adopted by users in the field of medium
and heavy plate. This paper introduces the features
of a large-sized robot, ARCMAN™ A80, and a smallsized
robot, ARCMAN™ A30, both newly developed.
ARCMAN™ A80 is a robot suitable for welding large
structures, such as construction machinery, and has
enhanced features for improving welding applicability,
including an expanded approach area around work
pieces, while inheriting the features of the conventional
ARCMAN™ XL. ARCMAN™ A30 is a small robot aimed at
applications in narrow spaces and features an operating
speed and arm shape particularly suitable for the
assembly process of shipbuilding.
|
|
| 33 |
Formation of Fine Microstructure in Weld Metal
Containing Mn-Ti based Oxides
|
|
|
|
Hidenori NAKO, Yoshitomi OKAZAKI, Dr. Hitoshi HATANO,
Ken YAMASHITA, Hideaki TAKAUCHI
|
|
|
The formation of fine acicular ferrite microstructure and
toughness improvement have been observed in a welding
metal in which inclusion particles containing Mn-Ti
based oxide are dispersed. The inclusion particles are
composed of MnTi2O4 , TiO2 , amorphous and MnS phases,
while the acicular ferrite has been nucleated from the
MnTi2O4 phase. The Baker-Nutting crystal orientation
relationship has been found between MnTi2O4 phase and
acicular ferrite, whereas the Kurdjumov-Sachs orientation
relationship has been found between the prior austenite
phase and acicular ferrite. It has been discovered that
the favorable lattice matching at the interface between the
prior austenite phase and acicular ferrite may possibly
have promoted the nucleation and growth of acicular
ferrite, as well as the lattice matching at the MnTi2O4 /
acicular ferrite interface.
|
|
| 41 |
Dissimilar Metal Joining Process "Element Arc Spot Welding"
|
|
|
|
Liang CHEN, Dr. Reiichi SUZUKI
|
|
|
Dissimilar metal joining between aluminum and steel
has mainly been performed mechanically, however, the
method has problems such as production constraints.
Hence, we have proposed element arc spot welding
(EASW) as a new method for dissimilar metal joining. The
new method comprises inserting a hollow steel element
(rivet) into a hole in an aluminum upper sheet, after
which, the molten filler metal is deposited by arc welding
in the hollow part of the element; that is, the element and
the lower steel sheet are firmly welded, while the upper
aluminum-alloy sheet is tightly held between them. Thanks
to the features of the joining mechanism, there is no
restriction on the strength of the steel sheet. The method
is also applicable to members with closed cross sections.
With appropriate elements and welding wires, EASW can
assure joint strength equal to or greater than mechanical
joining. It allows welding in all positions and tolerates a
gap of approximately 1 mm.
|
|
|
<Feature-Ⅱ> Machinery - Industrial Machinery and
Compressor Technology
|
|
|
| 50 |
Tire Uniformity Machine, LIBROTA®
|
|
|
|
Shinichiro IKAI, Yasuhiro MATSUSHITA
|
|
|
Tire uniformity machines are used to inspect the quality
of automotive tires. Two capabilities are emphasized, i.e.,
the measurement repeatability expressed by the variation
of measurement values when a tire is measured several
times and the cycle time for inspecting each tire. There
are various restrictions in reconciling these two, and
we have reconsidered the structure of mechanical parts,
including spindle and drum, and the control component
of the machine. As a result, it has become possible to
shorten the cycle time to 18 seconds, 10% faster than
before, while improving the measurement repeatability
to RFVσ≦1.69 N. This paper reports the outline of the
technology introduced for improving the measurement
repeatability and cycle time performance.
|
|
| 55 |
Newly Developed Large Size Continuous Mixer (LCM-IM)
|
|
|
|
Kazuo YAMAGUCHI, Yoshinori KURODA, Toru OKADA
|
|
|
A new generation continuous mixer has been developed
to cope with the advancement of bi-modal high-density
polyethylene (HDPE), which is more difficult to mix.
Basic mixing experiments were carried out to confirm that
the new continuous mixer, which has been developed on
the basis of a new mixing theory, effectively eliminates
the gels of the bi-modal HDPE film and exhibits mixing
performance superior to that of conventional continuous
mixers. Furthermore, a new technique for measuring the
action force of mixing has been developed. This technique
was used to obtain data, which was analyzed by a newly
established analysis method to confirm the mechanical
reliability of the new continuous mixer.
|
|
| 59 |
New Technology for Continuous Casting Machine
|
|
|
|
Tomonori NISHIOKA, Fumiki ASANO, Hiroshi KAWAGUCHI
|
|
|
In pursuit of high productivity, energy saving, steeltype
versatility, and more stringent quality, each
engineering company of steel making equipment has made
a variety of unique development and improvements of
continuous casting machines since its full-scale practical
applications in the 1960s. Kobe Steel has newly developed
an optimal support mechanism for a large tundish,
and a highly precise weighing device for tundish cars,
which are closely related to safety and workability. In
addition, the company has newly developed a structure,
capable of maintaining high rigidity and movements
without backlash for an extended period of time, for
the mold oscillator and supporting roll stand, which
can significantly affect the quality of cast blooms. This
paper introduces these technologies, which have been
employed in the continuous bloom casting equipment
for special steel-equipment that was delivered to Kobe
Steel's Kakogawa Works in January 2017.
|
|
| 66 |
Horizontal CIP Apparatus for Food
|
|
|
|
Tomoya MINAMINO
|
|
|
High pressure processing (HPP) technology attracted
attention in the 1980s as a non-thermal sterilization
method, and its research, development and practical
application were promoted in Japan. High pressure
food processing equipment, which did not spread widely
at that time, is now seeing increased demand due to
recent situational changes in food companies in Japan.
Conventional, vertical, cold-isostatic-pressing (CIP)
apparatuses are difficult to install in the facilities of food
companies; hence, a horizontal CIP apparatus, "FOOD
FRESHER," has been developed. This paper describes the
situation in high-pressure food processing technology and
outlines the newly-developed FOOD FRESHER and its
future development.
|
|
| 72 |
High-pressure Oil-free Screw Compressor
|
|
|
|
Shugo TAKAKI
|
|
|
Kobe Steel's screw compressors for process gas are widely
used in the fields of petrochemistry, general chemistry, oil
refining, gas businesses, etc., and, more recently, are being
used not only in on-land factories, but also in oceanic
platforms and offshore applications such as FPSO. In
recent applications that require relatively high discharge
pressure, such as flare gas recovery and off-shore VRU, for
which small compressors have conventionally been used,
medium-sized compressors are needed to respond to the
users' requirements for an increased gas flow rate. Now,
Kobe Steel has lined up medium sized, high-pressure oilfree
screw compressors, whose advantages and concepts
are introduced in this paper.
|
|
| 77 |
Large Integrally-geared Centrifugal Compressor
|
|
|
|
Keiichi SAEKI, Yasuhisa YAMASHIRO, Toshihisa SHIBATA,
Atsushi SANO
|
|
|
A newly developed centrifugal compressor has a large
capacity and incorporates a gear unit. An attempt was
made to downsize the compressor, and the cost has
been reduced by revising the procurement method of the
gear unit, etc. A full load test has been carried out on a
prototype machine in the company's proprietary facility
to confirm its performance and mechanical stability.
As a result of this development, the application range
of integrally-geared centrifugal compressors has been
doubled, enabling a response to the demands of the
expanding market.
|
|
| 81 |
Vertical Type Reciprocating Compressor for LNG Boil Off Gas (BOG) Injection |
|
|
|
Katsuhiro SEYAMA, Satoshi TEZUKA, Takashi OKUNO,
Kenji NAGURA, Naoki AKAMO
|
|
|
As the shipbuilding industry is enforcing environmental
regulations, low-speed dual-fuel engines, such as ME-GI,
are attracting rising attention. Such an engine requires
a gas-injection compressor (GIC) to supply LNG boil
off gas (BOG), and the demand for GICs is expected to
grow. Hence, KOBE Steel has developed a vertical type
LNG BOG reciprocating compressor suitable for GIC for
ME-GI engines. In developing the compressor, we have
utilized proven technologies, such as low temperature
suction, high pressure discharge, and a high-performance
oil-separation system. A vertical type suited to the
installation space on a ship has been adopted, and ease
of maintenance has been ensured. This paper describes its
development.
|
|
|
|
 |
|
 |
|
