 |
 |
 |
 |
No. 32 DEC. 2013
|
|
|
<Feature-Ⅰ> Welding and Joining Technologies
|
|
|
| 1 |
Recent Development of High-strength and Tough Welding Consumables for Offshore Structures
|
|
|
|
Dr. Yoshihiko KITAGAWA, Hiroyuki KAWASAKI
|
|
|
As the exploration fields for oil and gas resources expand into deeper and colder seas, higher strength and greater toughness are required for the structural materials, including welding materials, used in offshore structures. Recent offshore structures require structural materials having sufficient CTOD properties, including a yield strength of 460MPa or higher and good impact toughness down to -60°C. To meet such requirements, we have developed advanced welding consumables for shielded metal arc welding (SMAW), submerged arc welding (SAW) and flux-cored arc welding (FCAW). For SMAW and SAW consumables, the basicity of the flux was adjusted to reduce the oxygen content in the weld metal, thereby achieving good impact toughness down to -60°C, a high yield strength of over 500MPa, and a high CTOD value down to -40°C. The FCAW consumable has been improved with optimized deoxidizers and the appropriate addition of Ni and Mn to produce a weld metal having a very fine microstructure, thus achieving both a yield strength of over 690MPa and good impact toughness down to -60°C.
|
|
| 9 |
Robot Welding Process for Medium and Heavy Plate
|
|
|
|
Katsuyuki TSUJI, Akira OGAWA, Dr. Kei YAMAZAKI, Yimin YUAN
|
|
|
Welding processes are always required to have highefficiency, quality stability, and reduced costs. The advanced controllability of the welding power sources has enabled the control of the output waveform, using an advanced control law, which has realized a new process with high added value for medium and heavy plates, the Ultra-High Current GMAW process, tandem arc welding and "REGARC TM". The Ultra-High Current GMAW process is a highly-efficient welding process using single arc and offers large leg length, low-spatter and deep penetration, using special flux-cored wire and unique waveform control. Tandem arc welding reduces spatter generation by 70 percent compared with conventional equipment, thanks to its new waveform control. The advantage of this welding process is a high deposition rate and high speed welding. "REGARC TM" reduces spatter generation by 90 percent compared with the conventional process using CO2 gasshielded arc welding.
|
|
| 16 |
New Welding Process, "J-SolutionTM Zn", Suitable for Galvanized Steel in the
Automotive Industry
|
|
|
|
Shun IZUTANI, Dr. Kei YAMAZAKI, Reiichi SUZUKI
|
|
|
In the automotive industry, galvanized steel sheets have been applied for quality improvement. However, the porosity defects generated during welding and increased spattering cause a debasement of welding workability. Porosity-generating behavior, which had not hitherto been clarified, was observed in this study, which also examines a method of reducing both the porosity defects and spatter. The results indicate that releasing zinc vapor from directly under the arc to outside the molten pool is effective in reducing porosity defects. Based on this knowledge, the problem was solved by optimizing (a) the composition and size of the welding material, (b) the shielding gas composition and (c) the current pulse wave pattern. This new welding process was named the "J-SolutionTM Zn".
|
|
| 24 |
Expansion of "MX-MIG process" as Pure Argon Gas Shielded Welding Method - for Carbon Steel
|
|
|
|
Reiichi SUZUKI, Ryu KASAI
|
|
|
It used to be considered that pure argon (Ar) was inapplicable to metal inert gas (MIG) welding using steel wire. However, the newly developed process called "MXMIG," which involves the use of a special welding wire made by Kobe Steel, makes it easily applicable. Many new characteristics are obtained by the MX-MIG process, such as ultra-low spatter, fumes, and slag, as well as excellent bead shape, appearance and weld metal quality. These are the features that were conventionally impossible to achieve with reactive gas. This paper introduces the arc stabilization mechanism and general characteristics of the MX-MIG process, as well as the mechanism for improving the paintability, corrosion toughness and fatigue strength of the carbon steel weld joint. The non-slag characteristic contributes to improved paintability. On the other hand, the fatigue strength is improved by combining the bead shape (wetness) and the low temperature transformation of the crystal microstructure.
|
|
| 33 |
Effects of Post Weld Heat Treatment (PWHT) Temperature on Mechanical Properties of Weld Metals for High-Cr Ferritic Heat-Resistant Steel
|
|
|
|
Genichi TANIGUCHI, Ken YAMASHITA
|
|
|
Welded joints of high-Cr ferritic heat-resistant steel, ASTM A335 Gr. P91, were subjected to post weld heat treatment (PWHT) to improve mechanical properties and to reduce residual stress. We have measured the Ac1 of weld metals for Gr. P91 steel, containing varying amounts of Mn+Ni, and have examined the effects of PWHT temperatures on the mechanical properties of each weld metal. The upper limits of the PWHT temperature for the respective weld metals are considered.
|
|
| 40 |
Built-in Cable Type Welding Robot "ARCMANTM-GS"
|
|
|
|
Shuichi INADA, Makoto KONDO, Yoshihide INOUE, Tatsuji MINATO,
Dr. Yoshiharu NISHIDA, Takashi WADA
|
|
|
This paper describes the features of the "ARCMANTM-GS", a welding robot with built-in cables. The robot was launched in the market in September 2011. To reach deep inside hollow workpieces, the robot has a sufficient working area especially designed for an overhead-suspended system and has a torch-integrated arm that is suitable for teaching. These features make the "ARCMANTM-GS" a more versatile robot, enabling the welding of various workpieces and improving the customers' production. The robot is expected to see worldwide sales.
|
|
|
<Feature-Ⅱ> Energy Machinery and Equipment
|
|
|
| 45 |
Development and Approach to Future Market of the Eco-Radial Steam Turbine Generator
|
|
|
|
Atsushi YOSHIDA, Osamu MATSUTANI
|
|
|
A new power generation system, the Eco-Radial, has been developed and launched into the market. The system employs a radial turbine, designed for steam pressure up to 0.98MPaG. The manufacturing cost has been cut to 50% of the conventional cost as a result of various efforts such as downsizing, reducing the number of components and decreasing the machining time. This paper introduces the development of this new model and our approach to the future market.
|
|
| 51 |
Manufacturing Technology of Diffusion-bonded Compact Heat Exchanger (DCHE)
|
|
|
|
Yasutake MIWA, Dr. Koji NOISHIKI, Tomohiro SUZUKI,
Kenichi TAKATSUKI
|
|
|
The Diffusion-bonded Compact Heat Exchanger (DCHE) is a compact heat exchanger, and the demand for it is expected to increase in applications for weight saving or those calling for a compact plot area, as well as for use in floating plants. Kobe Steel has been working on the development and establishment of the manufacturing technology of DCHE, which is a compact and high strength micro channel heat exchanger. Its heat transfer performance has been evaluated by comparing it with the conventional shell & tube type heat exchanger, and its strength and fatigue have been evaluated using Kobe Steel's stress analysis technology and fatigue test. This paper introduces the features of DCHE and the activity involved in its development.
|
|
| 57 |
Microchannel Reactor (Stacked Multi-Channel Reactor: SMCR®) for Bulk Chemical Industry
|
|
|
|
Dr. Koji NOISHIKI, Yasutake MIWA, Akira MATSUOKA
|
|
|
A microchannel reactor (MCR) has high thermal performance and rapid mass transfer thanks to its small channels where the reaction takes place. The microchannels offer a field that is more reactive than that offered by conventional mixer-type reactors. The application of MCRs, however, is limited to products such as medicines that have high value and are produced in small volumes. This is due to the limitation of the flow capacity of an MCR. Against this background, Kobe Steel has developed a stacked multi-channel reactor (SMCR®) that enables mass production and is applicable to the bulk chemical industry. This report explains the technology of the MCR, the features and the construction of the SMCR and the use of an SMCR for development work aimed at commercialization.
|
|
| 64 |
LNG Vaporizer for LNG Re-gasification Terminal
|
|
|
|
Shinji EGASHIRA
|
|
|
Kobe Steel leads the world in LNG vaporizers. We design and fabricate "open rack type vaporizers (ORVs)" and "intermediate fluid type LNG vaporizers (IFVs)" for large LNG receiving terminals. This paper introduces the trends in the present LNG receiving terminals, the features of LNG vaporizers and topics having to do with the company's development of vaporizers.
|
|
| 70 |
Air-sourced 90°C Hot Water Supplying Heat Pump "HEM-90A"
|
|
|
|
Takahiro OUE, Kazuto OKADA
|
|
|
Kobe Steel has developed an air-sourced heat pump, "HEM-90A," for supplying hot water. This heat pump is capable of supplying hot water at 65-90°C to the heating process of factories making products such as foods, beverages, automobiles and chemicals. The newly developed heat pump has achieved the highest energy efficiency among air-sourced heat pumps for supplying hot water by circulation heating. This was made possible by using a two-stage twin-screw compressor modified for high temperature operation by selecting an adequate refrigerant and optimizing an air-sourced evaporator unit. This paper introduces the features and the performance of our newly developed heat pump.
|
|
|
|
 |
|
 |
|
