Jfe Steel Corporation

Mitsubishi Denki Kabushiki Kaisha

Hiroshi Nakata

Koji Yamashita

Takashi Kobayashi

Chikara Kami

Shunsuke Toyoda

Kaoru Sato

Yoshimasa Funakawa

Osamu Morimoto

Masaki Toyoshima

Tomoaki Shibata

Kinya Nakagawa

Shuji Kawamura

Akihide Matsumoto

Kunikazu Tomita

Takanobu Saito

Masatoshi Aratani

Tsuyoshi Shiozaki

Junji Shimamura

Sota Goto

Tetsuo Shimizu

Koji Iwata

Tomonori Kondo

Eiji Maeda

Ryoji Matsui

Masami Imanishi

Hiroaki Hama

Moriya Miyamoto

Minoru Suwa

Hiromichi Hori

Takeshi Yoshida

Hideaki Tagashira

Yasuhiro Matsuki

Takato Tamai

Takahiko Ogura

Nobuyuki Kageyama

Motohiko Urabe

Toshifumi Abe

Tetsuo Yamamoto

Yasuhiro Murao

Toru Inazumi

There are provided an electric resistance welded steel pipe for producing a high strength hollow stabilizer excellent in fatigue resistance and a high strength hollow stabilizer. In an electric resistance welded steel pipe () for producing a hollow stabilizer, an internal weld bead cut portion () has a three-peak shape and a depth (H) of a trough portion () of the three-peak shape is 0.3 mm or less and an angle (&#x3b8;) formed by a central portion in the circumferential direction of the trough portion () and the top of right and left peak portions () located on both the right and left sides of the trough portion () is 160&#xb0; or more and less than 180&#xb0;.

Electric resistance welded steel pipe for producing hollow stabilizer, hollow stabilizer, and production methods for same

There is provided an electric resistance welded steel tube having a yield strength of 896 MPa or more, and excellent low-cycle fatigue resistance, for coiled tubing without performing whole-tube quenching treatment and reheating-tempering treatment after performing electric resistance welding and a method for manufacturing the same. The steel tube includes, by mass %, C, Si, Mn, P, S, Al, Cr, Cu, Ni, Mo, Nb, V, Ti, and N at a specific content. The steel tube has a microstructure that contains 2% to 10% retained austenite and 20% or less martensite on a volume fraction basis, and the remainder being bainite. The yield strength is set to 896 MPa or more and the uniform elongation is set to 9.0% or more.

Electric resistance welded steel tube for coiled tubing and method for manufacturing the same

A hot-rolled steel sheet for a heavy-wall, high-strength line pipe, the steel sheet having a chemical composition including, in mass %, C: 0.02 to 0.20%, Mn: 0.80 to 2.10%, Si: 0.01 to 0.50%, P: 0.034% or less, S: 0.0050% or less, Nb: 0.01 to 0.15%, Ti: 0.001 to 0.030%, and Al: 0.001 to 0.080%, the balance being Fe and incidental impurities, the steel sheet having a microstructure in which a main phase is a continuous cooling transformation structure and in which {001}grains in a plane whose normal direction is the sheet width direction constitute an area fraction of 10% or less and have a combined size of 10 &#x3bc;m or less, wherein the steel sheet has a tensile strength of 520 MPa or greater, and, in a drop weight tear test, a temperature at which a percent ductile fracture reaches 85% is &#x2212;25&#xb0; C. or lower.

Hot-rolled steel sheet for heavy-wall, high-strength line pipe, welded steel pipe for heavy-wall, high-strength line pipe, and method for producing the welded steel pipe

There is provided a hot-rolled steel sheet suitable for manufacturing an electric resistance welded steel tube, having workability necessary for roll forming and high yield strength, for coiled tubing without performing whole-tube quenching treatment and reheating-tempering treatment after electric resistance welding. The steel sheet includes, by mass %, C, Si, Mn, P, S, Al, Cr, Cu, Ni, Mo, Nb, V, Ti, and N contained at a specific content. The steel sheet has a microstructure containing 3% to 20% martensite and 10% or less retained austenite on a volume fraction basis, the remainder being bainite. The yield strength is set to 600 MPa or more, the tensile strength is set to 950 MPa or more, and the uniform elongation is set to 7.0% or more.

Hot-rolled steel sheet for coiled tubing

A high-strength hot-rolled steel sheet for an electric resistance welded steel pipe has decreased variations in in-plane material properties, high strength, and excellent ductility. The high-strength hot-rolled steel sheet has a composition containing, in mass %, C: 0.10 to 0.18%, Si: 0.1 to 0.5%, Mn: 0.8 to 2.0%, P: 0.001 to 0.020%, S: 0.005% or less, Al: 0.001 to 0.1%, Cr: 0.4 to 1.0%, Cu: 0.1 to 0.5%, Ni: 0.01 to 0.4%, Nb: 0.01 to 0.07%, N: 0.008% or less, and further Mo: 0.5% or less and/or V: 0.1% or less so that Moeq defined as Moeq=Mo+0.36Cr+0.77Mn+0.07Ni is 1.4 to 2.2, and Mo and V are contained to satisfy 0.05&#x2264;Mo+V&#x2264;0.5; and has a microstructure containing, in volume fraction, 80% or more of a bainite phase as a primary phase and 4 to 20% of a martensite phase and a retained austenite phase in total as a secondary phase, where the bainite phase has an average grain size of 1 to 10 &#x3bc;m.

High-strength hot-rolled steel sheet for electric resistance welded steel pipe and manufacturing method therefor

A high-tensile-strength hot-rolled steel sheet is provided having a composition which contains 0.02 to 0.08% C, 0.01 to 0.10% Nb, 0.001 to 0.05% Ti and Fe and unavoidable impurities as a balance, wherein the steel sheet contains C, Ti and Nb in such a manner that (Ti+(Nb/2))/C&#x3c;4 is satisfied, and the steel sheet has a structure where a primary phase of the structure at a position 1 mm away from a surface in a sheet thickness direction is one selected from a group consisting of a ferrite phase, tempered martensite and a mixture structure of a ferrite phase and tempered martensite, a primary phase of the structure at a sheet thickness center position is formed of a ferrite phase, and a difference &#x394;V between a structural fraction (volume %) of a secondary phase at the position 1 mm away from the surface in the sheet thickness direction and a structural fraction (volume %) of a secondary phase at the sheet thickness center position is 2% or less.

Thick high-tensile-strength hot-rolled steel sheet having excellent low-temperature toughness and manufacturing method thereof

A steel material containing 0.01% to 0.07% C, 0.40% or less Si, 0.5% to 1.4% Mn, 0.1% or less Al, 0.01% to 0.15% Nb, 0.1% or less V, 0.03% or less Ti, and 0.008% or less N on a mass basis, Nb, V, and Ti satisfying Nb+V+Ti&#x3c;0.15, Cm satisfying 0.12 or less, is heated to a heating temperature of 1,100&#xb0; C. to 1,250&#xb0; C., finish-rolled in such a way that the accumulative rolling reduction at a temperature of 930&#xb0; C. or lower is 40% to 85% and the finished rolling temperature is 760&#xb0; C. to 870&#xb0; C., cooled to a cooling stop temperature of 500&#xb0; C. or lower in terms of surface temperature at an average cooling rate of 30&#xb0; C./s to 200&#xb0; C./s in terms of thickness-wise center temperature, naturally cooled for more than 10 s after cooling is stopped, and coiled at a coiling temperature of 400&#xb0; C. to 620&#xb0; C.

High strength hot-rolled steel sheet for welded steel line pipe having excellent souring resistance, and method for producing same

A thick-walled high-strength hot rolled steel sheet has a high tensile strength TS of 521 MPa or more and excellent low-temperature toughness. The steel material forming the sheet contains 0.02%-0.08% C, 0.01%-0.10% Nb, and 0.001%-0.05% Ti and is heated; C, Ti, and Nb satisfies (Ti+(Nb/2))/C&#x3c;4.

Thick-walled high-strength hot rolled steel sheet with excellent low-temperature toughness and method of producing same

A hot-rolled steel sheet for high-strength ERW pipes contains about 0.02% to about 0.06% C; about 0.05% to about 0.50% Si; about 0.5% to about 1.5% Mn; about 0.010% or less P; about 0.0010% or less S; about 0.01% to about 0.10% Al; about 0.01% to about 0.10% Nb; about 0.001% to about 0.025% Ti; about 0.001% to about 0.005% Ca; about 0.003% or less 0; and about 0.005% or less N, and at least one element selected from the group consisting of about 0.01% to about 0.10% V; about 0.01% to about 0.50% Cu; about 0.01% to about 0.50% Ni; and about 0.01% to about 0.50% Mo on the basis of mass. The group of C, Si, Mn, Cu, Ni, Mo, and V and the group of Ca, 0, and S satisfy specific relationships, and the microstructure of the steel sheet is composed of about 95% by volume or more bainitic ferrite.

Hot-rolled steel sheet for high-strength electric-resistance welded pipe having sour-gas resistance and excellent weld toughness, and method for manufacturing the same

In a failure diagnosis apparatus for a refrigerating cycle, a plurality of instrumentation amounts concerning the refrigerant such as the pressure and temperature of the refrigerating cycle apparatus or other instrumentation amounts are detected, the state quantities such as composite variables are acquired by making the arithmetic operation on these instrumentation amounts, and whether the apparatus is normal or abnormal is judged employing the arithmetic operation results. If learning is made during the normal operation, a current state is judged, and if learning is made by compulsorily performing the abnormal operation, or if the abnormal operating condition is operated during the current operation, a failure foretaste such as a critical operation can be made from a change in the Mahalanobis distance. Thereby, the secure diagnosis can be implemented with a simple constitution.

Equipment diagnosis device, refrigerating cycle apparatus, fluid circuit diagnosis method, equipment monitoring system, and refrigerating cycle monitoring system

A hot-rolled steel strip having superior low temperature toughness and weldability, which is suitably used as a starting material for high strength electric resistance welding pipe, is provided at a low cost without constructing new production facilities and increasing cost. The hot-rolled steel strip is low carbon steel containing at least one of about 0.5.% or less of Cu, about 0.5% or less of Ni, and about 0.5% or less of Mo, wherein Pcm represented by the following equation (1) is 0.17 or less:=(% C)+(% Si)/30+((% Mn)+(% Cu))/20+(% Ni)/60+(% Mo)/7+(% V)/10&#x2003;&#x2003;Equation (1),(where (% M) indicates the content of element M on a mass percent basis), and the balance includes Fe and incidental impurities. In addition, in the entire microstructure, the ratio of bainitic ferrite, which is a primary phase, is controlled to be about 95 percent by volume or more.

Hot-rolled steel strip for high strength electric resistance welding pipe and manufacturing method thereof

An inexpensive, compact digital radio receiver corrects IQ imbalance, non-orthogonal I and Q phases, and DC offset by a DSP. The digital radio receiver is equipped with an antenna, an RF/IF converter for converting a radio frequency into an intermediate frequency, an IQ separator for separating I and Q, a filter for eliminating a noise such as a radio frequency, a multiplying sampler for sampling the output of the filter, and a digital signal processing unit mainly comprised of the DSP which implements an algorithm for estimating and correcting an IQ distortion and also performs quadrature phase demodulation. The IQ distortion can be removed inexpensively by making use of a part of a standard radio operation, hardly requiring the use of hardware for adjustment.

Digital radio receiver

A synchronizing signal detection apparatus of the present invention comprises a demodulator for digitally demodulating input signals, a partial matching error counter for comparing every bit of the demodulated input signal bit pattern demodulated by said demodulator with a part of the known synchronizing signal bit pattern. The apparatus further comprises a remaining bit matching counter for comparing the input signal bit pattern with remaining bits of the synchronizing signal bit pattern used in the partial matching error counter, or with all synchronizing signal bit pattern, for every bit, when an error bit number, which is compared in the partial matching error counter, is equal or less than a first threshold value. When the error bit number compared in the remaining bits matching error counter is equal or less than a second threshold value, synchronizing signal is assumed to be detected. In the apparatus of the present invention, bit pattern comparison numbers are decreased.

Synchronizing signal detection apparatus

A heat storage type air conditioning system capable of performing refrigerant receiving and discharging control and oil quantity control, which, in operating the general cooling circuit and the cold radiating circuit simultaneously or separately, is free from difficulties that the compressor is damaged or the cooling capacity is lowered when the quantities of refrigerant in those circuits are excessively increased or decreased, and is able to continue the operations with the quantity of refrigerant and the quantity of ice machine oil adjusted to suitable values. In the heat storage type air conditioning system, evaporators are provided in a general cooling circuit driven by a compressor and in a cold radiating circuit driven by a refrigerant gas pump, respectively, so that those circuits operate independently of each other. Furthermore, bypass circuits are provided to allow refrigerant to flow between liquid pipes and between gas pipes in those circuits. In a cold storing operation, the bypass circuits are closed, so that a cold storing circuit is formed by the compressor, a condenser, a first pressure reducing mechanism, and a cold storing heat exchanger.

Heat storage type air conditioning apparatus

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Tokyo, Japan

Hiroshi Nakata