SUS304 Plate Research Articles

Prediction of Laser Welding Distortion in Cylindrical Shell Structures Using Direct Application of Inherent Strain

In this study, a simplified analysis method by directly applying inherent strain (DIS) at integration points to predict welding distortion of cylindrical shell structures was suggested. The 3D thermo-elastoplastic method demands substantial computational time. The strain as direct boundary (SDB) simplified method using virtual temperature encounters challenges in consecutive thermal structural analysis including welding distortion. The suggested method (that is, DIS) offers the advantage of enabling continuous thermal structural analysis after welding distortion analysis, with computational efficiency. To calculate inherent strain, lap laser welding with 2 mm and 2.6 mm SUS304 plates was performed, measuring fusion and heat-affected zone sizes via cross-sectional observations. Using the calculated inherent strain and our suggested direct input method, we conducted welding analysis and welding test on cylindrical shell structures. Comparison of welding distortion under same conditions revealed radial distortion difference within approximately 10%, corresponding with the experimental result and confirming a computational time reduction by over 2,000 times than those of thermo-elastoplastic analysis. Therefore, an efficient and accurate prediction of welding distortion was achievable through the suggested method.

A Graphene-Coated Silicon Wafer Plate Improves the Sensitivity and Reproducibility of MALDI-TOF MS Analysis of Proteins.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is widely used to analyze small and large molecules. However, proteins are difficult to analyze with MALDI-TOF MS in clinical applications because of their low ionization efficiency and heterogeneous crystallization with the matrix on the sample spots. Here, we investigate the potential of a customized graphene-coated silicon wafer (G/SiO2) plate for MALDI-TOF MS analysis of a clinically important protein, KPC-2, in comparison with a conventional stainless steel (SUS) plate. Our results demonstrate that the G/SiO2 plate outperforms the SUS plate in terms of sensitivity, reproducibility, and mass accuracy/precision across a wide range of molecular weights, even with highly complex samples. Furthermore, a five-day robustness test confirms the practical applicability of the G/SiO2 plate for the reliable identification of target protein(s) in MALDI-TOF MS analysis. Overall, our findings suggest that the use of the G/SiO2 plate holds great potential for improving the sensitivity and reproducibility of MALDI-TOF MS analysis for the identification of proteins, making it a promising tool for clinical applications.

Coalescence Behavior of Multiple Cracks in SUS304 Plate with under Creep Rupture Conditions

A creep test was conducted to clarify the coalescence behavior of cracks in a SUS304 flat plate with multiple cracks on different planes. The test temperature is 600 degrees. The shape of the specimen is a plate, and electrical discharge machined (EDM) notches were introduced on both sides of the central smooth part. Then, a fatigue pre-crack was generated at the tip of the notch. The position of the crack was expressed by the distance between the crack surfaces and the distance between the crack tips. As a result of the experiment, the cracks coalesced when the distance between the crack planes was shorter than about 3 mm. On the other hand, when the distance between the crack surfaces was about 7 mm, no crack coalescence was observed, and there was a change point in the crack coalescence behavior. It was found that the change point of the coalescence behavior of the crack obtained in the creep test satisfied codes for nuclear power generation facilities (JSME S NA1-2019). As a result of fracture surface observation, it was found that the crack growth from the fatigue pre-crack due to creep is due to grain boundary rupture regardless of the presence or absence of crack coalescence.

Fracture Strength and Crack Coalescence Behavior of SUS304 Plate with Multiple Cracks

Tensile tests were conducted at room and high temperature to clarify the fracture strength and crack coalescence behavior of multiple cracks in SUS304 flat plates. The shape of the specimen is a plate, and electrical discharge machined (EDM) notches were introduced on both sides of the central smooth part. Then, a fatigue pre-crack was generated at the tip of the notch. The position of the crack was expressed by the distance between the crack surfaces and the distance between the crack tips. As a result of the tensile test at room temperature, when the distance between the crack surfaces was shorter than about 8 mm, the cracks coalesced. On the other hand, when the distance between the crack surfaces was about 10 mm, no crack coalescence was observed, and there was a change point in the crack coalescence behavior. As a result of the high temperature test, crack coalescence was observed when the distance between the crack planes was about 8 mm, but the change point of the crack coalescence behavior is unknown because there is no data. It was found that the change points of the coalescence behavior of the cracks obtained in the experiment satisfy codes for nuclear power generation facilities (JSME S NA1-2019).

Study on the SUAM Double Magnet System for Polishing

Superconductive assisted machining (SUAM) is a novel machining method that eliminates tool interference via magnetic levitation tools. In our study, we developed a double magnet system (DMS) to increase the maximum power of the holding force and stabilize the magnetic rotation during polishing via the higher magnetic flux compared to a single magnet system (SMS). The maximum magnetic flux density of the DMS was approximately 100 mT higher than that of the SMS. In these cases, the entire holding force increases as the distance between the superconducting bulk and lower magnet decreases. The attractive forces are maximum around a displacement of 6 mm, although the repulsive and restoring forces increase spontaneously. The polishing performances of the DMS on the SUS304 and A1100P plates were evaluated using water-based diamond slurries, for equal levitation amounts. The amount removed by the DMS increased for the A1100P and SUS304 substrates compared to that by the SMS. In this case, we observe that the deviation of the polishing area on the DMS decreases compared to that of the SMS, reflecting a more stable rotation and movement due to the higher holding force.

Impact resistance of steel materials to ballistic ejecta and shelter development using steel deck plates

The destruction caused by ballistic ejecta from the phreatic eruptions of Mt. Ontake in 2014 and Mt. Kusatsu-Shirane (Mt. Moto-Shirane) in 2018 in Japan, which resulted in numerous casualties, highlighted the need for better evacuation facilities. In response, some mountain huts were reinforced with aramid fabric to convert them into shelters. However, a number of decisions must be made when working to increase the number of shelters, which depend on the location where they are to be built. In this study, we propose a method of using high-strength steel to reinforce wooden buildings for use as shelters. More specifically, assuming that ballistic ejecta has an impact energy of 9 kJ or more, as in previous studies, we developed a method that utilizes SUS304 and SS400 unprocessed steel plates based on existing impact test data. We found that SUS304 is particularly suitable for use as a reinforcing material because it has excellent impact energy absorption characteristics due to its high ductility as well as excellent corrosion resistance. With the aim of increasing the structural strength of steel shelters, we also conducted an impact test on a shelter fabricated from SS400 deck plates (i.e., steel with improved flexural strength provided by work-hardened trapezoidal corrugated plates). The results show that the shelter could withstand impact with an energy of 13.5 kJ (2.66 kg of simulated ballistic ejecta at 101 m/s on impact). In addition, from the result of the impact test using the roof-simulating structure, it was confirmed the impact absorption energy is further increased when artificial pumice as an additional protective layer is installed on this structure. Observations of the shelter after the impact test show that there is still some allowance for deformation caused by projectile impact, which means that the proposed steel shelter holds promise, not only structurally, but also from the aspects of transportation and assembly. Hence, the usefulness of shelters that use steel was shown experimentally. However, shelter construction should be suitable for the target environment.

Brazing of Stainless Steel Using Electrolytic Ni-P Plating Film and Investigation of Corrosion Behavior

Electrodeposited Ni-11 mass%P alloy plating film was fabricated on the surface of stainless steel SUS304 to conduct brazing of SUS304 plates for a heat exchanger. Brazing of SUS304 plates with electrodeposited Ni-11P layers was carried out using a hydrogen reducing furnace. The microstructure and joint strength of the brazed joint were also investigated. From the result of the microstructural observation of the cross section of the joint, it was found that the brazing filler metal is homogeneously distributed without defects such as voids between the SUS304 plates. The results of electrochemical measurements showed that the P-concentrated phase in the Ni-11P alloy is preferentially dissolved in NaCl aqueous solution.

Evaluation of energy spectrum around structural materials in radiation environments

Structural materials such as stainless steel (SUS) in nuclear reactor are exposed by the environment of ionizing radiations so that their corrosion and degradation take place. These radiation effects depend strongly on the quality of radiation (energy, kind) around the materials. The metallic materials with various thickness have been examined in previous works on the radiation effects, but not with a common thickness. The different thickness would give the different radiation quality, leading to the different results of radiation effects on the materials. In this work, when radiation sources of 137Cs, 90Sr and 90Y were assumed to be put in the front of a plain SUS304 plate as a typical material submerged in water, energy spectra of secondary photons and electrons at the front and back sides of plate were simulated with changing the thickness of plate, and spacing between the source and plate by using a Monte Carlo calculation code of PHITS.In the case of 137Cs gamma-ray (monochromatic 662 keV), the energy spectra at the front side was smaller than those at the back side due to the existence of plate. Then the dependence of spectra on the plate thickness was observed more clearly at the back side than at the front side. In the cases of 90Sr and 90Y beta-rays (maximum 546 and 2284 keV), the energy spectra were clearly different from those in the case of gamma-ray. At the front side, the energy and flux of electrons were higher than those of photons. Also, the energy spectra of electrons and photons were not dependent on the plate thickness. At the back side, the energy and flux of electrons were much lower than those of photons reversely. It was clearly shown how the energy spectra of photons and electrons varied with the incident radiation type, the spacing, and the thickness.The average energies of secondary radiations were further estimated, and the changes of incident radiation to the secondary ones were discussed especially in terms of the lowering of radiation energy.

Micro-Brazing of Stainless Steel Using Ni-P Alloy Plating

A Ni-P plated layer of 20 μm thickness containing 11 wt.% P was formed on the surface of a stainless steel (SUS304) plate by electroplating. The microstructure and joint strength of the brazed joint with the electroplated Ni-11P layer were investigated. The results indicated that the filler metal was homogeneously distributed between the SUS304 plates and no voids or flaws formed in the brazed filler zone. Fe-Ni-Cr solid solutions were formed at the brazed interface. Moreover, P was mainly concentrated in such brazed filler zone to form P-containing phases. The average shear strength of the brazed joints was determined to be 47.3 MPa. The results demonstrated that the brazing of SUS304 plates using the electroplated Ni-11P layer as the filler metal was successfully realized.

Influence of Welding Current on Formation of Weld Bead in TIG Welding for Joining Thin Plates

In this paper, a new (novel) welding technology has been applied to join 0.1 mm thin plates. An initial study on the influence of welding current on the welding properties for stainless steel SUS304 plates is discussed in this paper. The weld bead appearance on both top surface and bottom surface was observed by microscope to indicate the change of weld bead size and welding defects. The results showed that by utilizing a constricted nozzle, a good weld bead is found out when the arc length is too short (0.3 mm), welding speed is very high (3000 mm min-1) and base metal is very thin (0.1 mm) with suitable welding conditions.

Resistance spot welding of metal/carbon-fibre-reinforced plastics and applying silane coupling treatment

ABSTRACTDissimilar materials joining of SUS304 and carbon-fibre-reinforced plastics consisting of short fibres and thermoplastics was performed. The materials were joined by series resistance spot welding. The electrodes were pressed on the metal plate of the lap joint of metal/carbon-fibre-reinforced plastics. The SUS304 plate was heated by resistance heating, causing the thermoplastic near the interface to melt slightly because of heat conduction. SUS304 could be joined directly to carbon-fibre-reinforced polyamide and modified polypropylene, but not to polyphenylene sulphide. The joining area increased with an increase in the welding current and welding time, so did the tensile shear fracture load. Furthermore, the silane coupling agent treatment of SUS304 was highly effective in increasing the joining strength.

Wetting Behavior of Falling Liquid Film Flowing on a Plate with a Side Wall

The wettability of liquid film flowing on an inclined plate is extremely deteriorated if there is a vertical wall on the channel side. In this study, an experimental study was conducted to investigate the influence of the side wall on the dryout of liquid film flow. The film surface forms a meniscus having a minimum film thickness near the side wall. The thin film thickness causes the dryout of film flow at lower flow rate. To avoid the appearance of the minimum thickness, the test channels of SUS-304 plate having circular side walls with various curvature radii RS were manufactured and the surface profiles of liquid film were measured experimentally for three kinds of test liquids. The meniscus profile was flattened at appropriate radius of curvature, i.e., RS.~6 mm for θR=20～30°(θR : receding contact angle) in this experiment. The critical Weber number at which dryout disappears is lowered remarkably and is recovered to the value those experienced for the flat plate without side walls.

Facile fabrication of superhydrophobic surfaces with hierarchical structures

Hierarchical structures were fabricated on the surfaces of SUS304 plates using a one-step process of direct microwave irradiation under a carbon dioxide atmosphere. The surface nanostructures were composed of chrome-doped hematite single crystals. Superhydrophobic surfaces with a water contact angle up to 169° were obtained by chemical modification of the hierarchical structures. The samples maintained superhydrophobicity under NaCl solution up to 2 weeks.

摩擦重ね接合によるステンレス鋼と炭素繊維強化熱可塑性樹脂との異材接合

The effect of joining speed on the joining strength of the dissimilar materials joint of the SUS304/ carbon fiber reinforced thermoplastic (CFRTP) was investigated. SUS304 plates (150mm×75mm×2.0mm) and CFRTP (consisted of PA6 matrix and 20wt% carbon fiber) plates (150mm×75mm×3.0mm) were joined by friction lap joining (FLJ) using rotational WC-Co tool. Different joining speeds in the range from 1.67mm/s - 16.7mm/s and the tool rotation speed of 8.33 s-1 were selected as processing conditions. Direct joining of SUS304/CFRTP was accomplished at all of joining speeds by FLJ. The tensile shear strength of the joint increased with increasing joining speed up to 3.33mm/s, however, it decreased from the joining speed of 3.33mm/s to 16.7mm/s. The interfacial fracture occurred at all of joining speeds. The fractured surface analysis of SUS304 revealed that teared fragments from the CFRTP base plate were bonded to SUS304. At the lower joining speed, the excessive heat input caused thermal decomposition of PA6 from the matrix of CFRTP resulted bubbles; the joint strength was decreased because of these bubbles. The shortage of the heat input at the higher joining speed caused insufficient wetting of molten PA6 to SUS304, which resulted in the decreased strength of the joint.

A hybrid nondestructive testing method of pulsed eddy current testing and electromagnetic acoustic transducer techniques for simultaneous surface and volumetric defects inspection

In this paper, a hybrid nondestructive testing (NDT) method combining with the pulsed eddy current testing (PECT) method and the electromagnetic acoustic transducer (EMAT) method has been proposed and validated through numerical simulations and experiments. First, a numerical code is developed for the simulation of hybrid EMAT/PECT signals based on the developed EMAT and PECT code. Second, based on the numerical simulation, the influences of the eddy current induced by the excitation coil and the eddy current due to the velocity effect of the ultrasonic wave are compared and analyzed. In addition, the features of the EMAT and the PECT signals are analyzed respectively. Third, several signal separation and extraction methods are proposed on the basis of the spectral analysis and filtering strategies for extracting EMAT and PECT signals from the mixed signals of the hybrid EMAT/PECT method and their validity are evaluated through experiments. Finally, hybrid EMAT/PECT experiments are conducted and three types of defects (surface defects, bottom thinning defects, composite defects) in an aluminum plate and a SUS304 plate are successfully detected at the same time using the proposed hybrid NDT method and the signal feature parameters. Based on the numerical and experimental results, the proposed hybrid PECT/EMAT NDT method is demonstrated both high detectability and high efficiency for detecting surface and volumetric defects at the same time.

High-Temperature Reactions of Cesium Molybdate on 304 Stainless Steel

During a severe accident in a Boiling Water Reactor (BWR), cesium is one of fission products that could be released from nuclear fuel to the reactor vessel and to deposit on the reactor coolant system that is made of stainless steel (SUS). Recently, it has been informed that the released form of cesium is predominantly cesium molybdate. (Cs2MoO4). Under vapor pressure, at high temperature, the deposition of Cs2MoO4 on the surface of oxide SUS could cause some chemical reactions. However, the type of reactions as well as the thermodynamics have not been confimed yet. The aim of this work is to clarify the possible reactions of Cs2MoO4 on the SUS surface at high temperatures. Cs2MoO4 powder was placed in a platinum boat and heated at 1573 K. Either SUS304 or platinum plates were placed downstream at different distances corresponding to temperatures ranging from 1554 to 547 K. The carrier gas was pure argon or argon saturated with steam at 70°C. The flow rate is 100 ml/min. The deposits on SUS304 and platinum plates were examined by X-Ray diffraction equipment (XRD), the micro-Raman spectroscopy and the electron probe micro analyzer (EPMA). The exit gas was passed through the (1%wt HNO3 + H2O) solution. The solution was analyzed by inductively coupled plasma mass spectroscopy (ICP-MS). In dry argon, the obtained deposits on Pt were Cs2MoO4. But on SUS304, the deposits were mainly Mo metal at ~1500 K, then Cs2MoO4 and Cs2Mo2O7 at ~1220K. At further downstream, the deposit were mainly Cs2MoO4. In Ar+steam, on Pt surface, at temperature higher than 1500 K, the deposit could not be obtained, this was probably due to the Cs2MoO4 prefered to stay in gas phase at this stage, but at the temperature below 1200 K, which is close to the melting point (1213 K) of Cs2MoO4, the deposits were predominantly Cs2MoO4. On the surface of SUS304 in Ar+steam, various reactions happened, depending on the temperature. The reaction became even complicated due to the vaporization of CrO2(OH)2. Molybdenum-containing species were found at higher temperatures. But there was no sign of cesium-containing species in SUS304, except for those found on the plates at the low temperatures below ~730 K, where Cs was found as Cs2MoO4.

GS0414 鉛フリーはんだ中のステンレス鋼の初期腐食挙動

In this study, the initial corrosion behavior of several stainless steels were examined. The materials were SUS304, SUS316 and pure Sn plate. They were decided corrosion times up to 1000hr in the use of SUS304 and 2000hr in the use of SUS316 at 500℃, respectively. After corrosion test, they were observed the cross section of reaction layer by OM and SEM. As a result, it was found that the reaction layer was formed at the interface between stainless steel and Sn plate after an incubation time. In the incubation time, the passive film made by Cr_2O_3 suppressed the diffusion of Sn into stainless steels. The strong stability of Cr_2O_3 film by the presence of Mo made strong the corrosion resistance of SUS316 against Sn higher than SUS304.

쐐기 슬래밍에 관한 실험적 연구

This paper presents the results of experimental work on the wed ge slamming impact problem. An experiment was done with a wedge model. The deadrise angle of the wedge was 4°. The model was made in two parts: the outside part was made of a 5-mm-thick steel plate that could be assumed to be a rigid body, and the inside part was made of a thin SUS plate that could be assumed to be an elastic body. Thin SUS plate thicknesses of 2 mm and 3 mm were used to determine the effect of plate rigidity. The drop height was varied from 0. 25 m to 1 m to determine the effect of a large deformation.

1005 Study on processing the surface of SUS304 plate with electrochemical magnetic abrasive finishing

Recently, to obtain a smooth surface of low roughness with high efficiency which is increasingly desired to be in precision machining. However, it is difficult for traditional machining technologies to achieve both high accuracy surface and high machining efficiency. This study is focused on application of an effective finishing method, which combines electrochemical machining (ECM) and magnetic abrasive finishing (MAF). Before this study, a novel complex machining tool that is capable of achieving two different processes has been designed. Then, a series of comparative experiments have been conducted in order to investigate the effect of electrochemical magnetic abrasive finishing (EMAF). The results show that EMAF process is able to obtain slightly higher quality surface and more material removal, which compares with the traditional MAF process. Furthermore, it is suggested that the combining method effectively reduces machining time.

An Analysis of Stainless Steel Micro Square Hole-Flange Using Stretching Processes

This study is focused on the influences of micro stretching process, miniaturized of micro square hole-flange to stainless steel (SUS304) material, and different thicknesses (0.2, 0.1, 0.05mm) of plate. By undergoing finite element program analysis of material parameter corrected by scale factor, we can discover the differences of different thicknesses of plate during micro stretching forming process. The finite element method in this paper is combined with the plastic flow rule of Dynaform and LS-DYNA solver, finite element deformed theory, and updated Lagrangian formulation to simulate the process of micro square hole-flange. The point of this research is by simulating and analyzing all datum of micro stretching forming process, relation between punch load and stroke, distribution of thickness, distribution of stress and strain, the maximum diameter of flange’s hole and the maximum height of flange. Design three pairs of micro square hole-flange tool undergoing micro stretching experience through SUS304 plate. Compare the experience to the results of the simulation to test the reliability of this analyzing program. Through finite element analysis and the results of the experience, we can discover that the minimum of the thickness, the biggest stress and major strain centralize areas where blank and punch corner meet.