Kawasaki, Japan
Kawasaki, Japan

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Brossard J.M.,Veolia Recherche et Innovation | Maad F.,Veolia Recherche et Innovation | Chartier J.,Veolia Recherche et Innovation | Chavrot R.,Veolia Recherche et Innovation | Kawahara Y.,Dai - ichi High Frequency
Oxidation of Metals | Year: 2017

Increase in the efficiency of energy recovery facilities is one of the challenges facing waste-to-energy (WtE) operators in the EU. To achieve this target, one option is optimization of the water/steam cycle to increase electrical efficiency. Nevertheless, increase in steam temperature in heat exchanger tubes results in increased fireside corrosion risks, particularly in superheater tubes, where severe corrosion loss of materials, frequent shutdowns for repairs and high operational costs occur. In this study, two heat-treated self-fluxing Cr–Mo–Si–B–Ni base alloys containing, respectively, 15.6 and 16.4 wt.% Cr, were applied to low- and high-temperature pendant superheater tubes (LTSH and HTSH). Detailed analyses for flue-gas and metal temperatures in service at different locations of the pendant tubes (around 850 and 400 °C, respectively) and analyses of deposits collected on both tubes (Na, K, Ca, Si, Zn, Pb, Cl, S) were conducted. Both coatings exhibited a corrosion rate close to ones reported for Inconel 625 in similar conditions. Localized corrosion was found and associated with molten phase-assisted corrosion mechanism damaging Si-rich protective layer. Correlations between corrosion rate and %Cr in the coating, Tflue-gas, Tmetal and amount of molten phase in deposit are presented. © 2017 Springer Science+Business Media New York

Isomoto Y.,Hiroshima University | Kawanishi T.,Hiroshima University | Kawahara Y.,Dai - ichi High Frequency
Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals | Year: 2013

Self-fluxing alloys are useful for component materials as coatings in energy conservation systems and power plants due to high resistance of high temperature corrosion and erosion. However, the mechanical properties of the self-fluxing alloy coatings at high temperatures have not been precisely investigated. In order to develop highly durable coatings and apply to practical services, we focused on measurements of hardness and fracture toughness for the self-fluxing alloys at room and high temperatures. Spherical particle impact tests were conducted for three types of self-fluxing alloys to obtain dynamic hardness and dynamic fracture toughness. Three point bending tests were additionally performed. As results, the hardness and fracture toughness of the three self-fluxing alloys were found to be almost constant at room and high temperatures up to 873 K, although a little decrease in fracture toughness occurred at 1073 K. The fracture toughness related to elastic modulus and F/C1-5 (F: load, C: crack length), and have a tendency of increasing with increase in Brinell hardness. © 2013 The Japan Institute of Metals and Materials.

Kawahara Y.,Dai - ichi High Frequency | Matsubara Y.,Dai - ichi High Frequency
Materials Science Forum | Year: 2011

High durability, quality control and prediction of deterioration are key issues for the thermal spray coatings applied to fossil fuel and waste burning boilers. Small electrical resistance inspection (SERI) has been developed and applied for boilers to quantitatively evaluate the relationship between the deterioration mechanisms and the coating defects as well as life-times of coatings. Changes in the electrical resistance (ER) of coatings showed a good correlation with the deterioration causes and also with the bonding strength of the coatings. On the other hand, new processes such as thermal spraying and automatic fusing (SFU) process by high frequency induction heating have been developed to manufacture highly durable coatings. These SFU coatings, which are 0.5∼3 mm in thickness and contain chemically bonded and dense NiCrSiB alloy layers have been found to have excellent durability which is almost equal to that of 625 weld overlays used in many WTE plants. Applications of these technologies are in progress to realize coatings with high cost performance, high efficiency and easy maintenance. © (2011) Trans Tech Publications.

Kawahara Y.,Dai - ichi High Frequency
Oxidation of Metals | Year: 2016

Localized corrosion (LC) sometimes appears in boiler tubes exposed in severely corrosive combustion gases including Cl, S and O, but prediction and on-site maintenance of LC is actually difficult in many cases. Therefore understanding the cause of LC is considered to be important to maintain safety services and estimate lifetime in high temperature facilities. This LC occurs due to formation of partially different corrosive conditions due to fuels, condition of combustion, designing of boilers, and materials. In this paper, investigation results of macroscopic LC and influenced factors formed in actual boilers were described with the four cases of fossil fuel, biomass and WTE boilers, and also described against any coatings. Mechanisms of each LC were considered individually by using cut-off samples of damaged tubes, detailed analyses of corrosive environments and results of laboratory tests. From these considerations, protective oxide layers and not only static factors but also dynamic factors arising in operated conditions such as temperature and composition fluctuations were concluded to be important for the accurate lifetime evaluations of tube materials and coatings. © 2015, Springer Science+Business Media New York.

Dai - ichi High Frequency and Nanotherapy Co. | Date: 2014-09-22

Magnetic flux irradiation devices having a cylindrical coil and a magnetic core including an optical transmission path are provided. Magnetic cores are also provided. Methods and systems for using such devices are also provided. The optical transmission path is configured to transmit light incident on an irradiation target, or thermal radiation emitted from the irradiation target.

Dai - ichi High Frequency and Nanotherapy Co. | Date: 2014-09-22

Magnetic flux irradiation devices having an adjustable or a replaceable magnetic core are provided. Magnetic cores are also provided. Methods and systems for using such devices are also provided. The devices and magnetic cores are configured to permit easily changing an irradiation pattern of the magnetic flux, depending on a positional relation between the magnetic flux irradiation device and the irradiation object.

Dai - ichi High Frequency | Date: 2014-10-06

A ferromagnetic-particle manufacturing apparatus includes: a single mode cavity that resonates with a microwave of a predetermined wavelength; a microwave oscillator electrically connected to the single mode cavity and configured to introduce the microwave of a predetermined wavelength into the single mode cavity; a pipe disposed to pass through an inside of the single mode cavity, the pipe being formed of a dielectric material; a pump configured to introduce, from one end of the pipe, an alkaline reaction liquid containing metal ions of a ferromagnetic metal; an impedance measuring device configured to measure an impedance of the single mode cavity; and a pump-flowrate deciding unit configured to decide, based on a measurement result of the impedance measuring device, a pump flowrate by which the impedance of the single mode cavity becomes a predetermined value or more; wherein the pump is configured to introduce the reaction liquid at the pump flowrate decided by the pump-flowrate deciding unit; and wherein ferromagnetic particles are generated by reacting the reaction liquid.

Dai - ichi High Frequency | Date: 2013-08-28

Provided is an alloy-coated boiler component which is to be welded at an end thereof, wherein a melted coating (15) with a first alloy material comprising not less than 1.5 % and not more than 2.5 % of B, not less than 3.5 % and not more than 4.0 % of Si, not more than 0.4 % of C, and not less than 12.0 % and not more than 17.0 % of Cr, and the balance being Ni and incidental impurities, is applied to the metallic base material on an end region including the end and its proximity and, a melted coating (16) of a second alloy material comprising more than 2.5 % and not more than 4.0 % of B, more than 4.0 % and not more than 5.0 % of Si, not less than 0.5 % and not more than 0.9 % of C, and not less than 12.0 % and not more than 17.0 % of Cr, and the balance being Ni and incidental impurities, is applied to the metallic base material on a non-end region other than the end region (percentages are expressed in terms of mass percentages). This alloy-coated boiler component has melted coatings which can be formed by thermal spraying-fusing treatment on the whole area of the metallic base material and the melted coating formed on the end region is superior in thermal shock resistance and resistance to shock.

A metal pipe bending apparatus comprises heating means for fully circumferentially heating a portion of a metal pipe which is an object for a bending process, propulsion means for propulsively driving the metal pipe toward the heating means in an axial direction of pipe, guiding means including a cramp arm for cramping the metal pipe and configured for pivotal movement about a pivot shaft, for cramping a point in front of a region of the metal pipe heated by the heating means with the cramp arm, revolving the cramp point about the pivot shaft in association with the metal pipe propulsively driven by the propulsion means, and thereby applying a bending moment to the metal pipe, and compression means for causing a compression force to act on the metal pipe by applying a draw-back force to the metal pipe through the cramp arm with the pivot shaft serving as a fulcrum, where the draw-back force includes a force in a direction opposite to a direction in which the metal pipe is propulsively driven by the propulsion means. The compression means is disposed such that a distance from a point at which the draw-back force is applied to the pivot shaft is larger than a distance from a point at which the metal pipe is cramped by the cramp arm to the pivot shaft. The amount of reduced thickness can be further restrained without requiring an increase in compression driving force in a metal pipe bending process.

Dai - ichi High Frequency | Date: 2014-09-05

drying apparatus; recuperators; steamers; evaporators; distillation apparatus; heat exchangers; industrial furnaces; boilers; boilers for industrial plants; boiler tubes for boilers; boiler tube panels for boilers.

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