Polished Steel Plates Research Articles

Laser modification of heating surfaces: A new approach to reduce boiler slagging

Slagging and fouling of boilers are typical technological problems in the combustion of solid fuels (especially coal and biomass). This study proposes a novel approach based on laser texturing of the near-surface layer of steel used to make heating surfaces of coal-fired boilers. This approach is aimed at improving the resistance of metal surfaces to slagging. The formation of slag deposits on the surfaces of AISI 310 S steel modified by laser radiation has been experimentally studied. The formation of slag melt was analyzed on the surface of modified and polished steel plates during heating to 1400 °C. High-temperature heating and interaction with slag led to a change in the chemical composition of the steel. A significant increase in the chromium content (up to 47%) of the steel surface and the transformation of its texture with the formation of grains up to 2.5 µm in size were established. Laser surface treatment significantly increased the resistance of the steel to such changes and also reduced the grain size to 1.5 µm. As a result of laser modification of surfaces, the temperature of slag formation shifts to higher values (higher by 60–75 °C compared to the unmodified polished surface). The anisotropic texture (cauliflower type) contributed to a decrease in the size of the slag spreading front, and also had by self-cleaning properties from the mineral melt. The latter allows to increase the reliability and energy efficiency of boiler equipment.

Bionic Ring Grooves Design and Experiment of the Suction Cup Applied in Oil-Immersed Substrate

The vacuum suction cup is often used as an end effector and widely used in wall-climbing operations. However, there are few vacuum suction cup designs and applications for oil-immersed substrates. Inspired by the surface morphology of the octopus sucker, bionic suction cups with different numbers, diameters, and spacings of the ring grooves were designed. Their normal adsorption force was evaluated on the untreated and polished steel plate in oil. The test results showed that ring grooves positively affected the adsorption force. The bionic suction cup with a groove number of 3, a diameter of 0.5 mm, and a spacing of 3 mm was the most excellent in the test. It achieved normal adsorption forces of 54.83 ± 0.48 N and 43.89 ± 0.69 N on the untreated and polished steel plate. Compared with the standard suction cup, it increased by 32.31% and 12.28% on the untreated and polished steel plate. The regression model between the normal adsorption force and design factors was established based on the adsorption force test results, and the influence law of the ring groove structure parameters on the adsorption force of suction cups on oil-immersed substrates was analyzed. The order of significant effects of groove design parameters on normal adsorption forces was groove diameters, spacings, and numbers. The finite element analysis (FEA) results show that the ring grooves could significantly increase the contact pressure, frictional stress, and sliding distance between the suction cup and the substrate. The ring groove structure effectively improves the adsorption force of the suction cup on the oil-immersed surface by forming a more effective seal and increasing the friction force and adsorption area. This study could provide a reference for developing the actuator of the oil-immersed or lubricated climbing machine.

DEFORMATION BEHAVIOR MATHEMATICAL MODELING OF A POLYMER MATERIAL LAYER WITH TECHNOLOGICAL HOLE FOR A LUBRICANT

Mathematical modeling of the flat layer of a polymeric material deformation behavior with a polished steel plate within the framework frictional contact was carried out of this work. The influence of the technological groove geometric configuration for the lubricant on the contact unit deformation is considered. The lubricant volume in the calculation scheme does not take into account that does not correspond to the favorable occasion of lack of lubrication in the recess. The parameterized model creation of a polymer layer portion with one technological recess with a different base rounding radius from 0.5 to 2 mm with a step of 0.25 mm is done. The technological recess geometrical influence on the deformation of its profile at loads from 5 to 90 MPa was established within the framework of the study. Changes in the cross-sectional area of the recess, the maximum level of the plastic deformations intensity, contact pressure, contact tangential stress and the contact interaction area from the load and the rounding radius are established. The contact zone parameters redistribution due to an increase in the contact interaction area for all rounding versions for the technological recess base for the lubricant occurs at loads of more than 40-50 MPa. The design with a rounding radius of 2 mm has a number of advantages: minimum deformation of the technological recess area, the minimum level of the maximum plastic deformations intensity, the maximum contact interaction area, etc.

Influence of Particle Size on Anti-Adhesion Effect of Surface Polished Steel Plate

In this paper, we examined the influence of particle size on anti-adhesion effect of a surface polished steel plate. SiO2 spherical powders and stainless steel plates with seven kinds of surface roughness were used for the investigation. The adhesion tests of SiO2 powders to the polished stainless steel plates were performed using powders of nominal size 9 and 13μm. In the case of 13μm powder, the obvious adhesion and deposition of powder was not observed for all steel surface conditions. However, strong adhesion of particles and thin deposition layers were observed for 9μm powder, being independent of surface roughness of the steel plates. The size of adhered particles on the steel plate were measured by SEM observations in order to examine the adhesion mechanism of SiO2 particle to the polished stainless plate substrate. As a result, adhesion of 3-5 μm particles to the steel surface was largely independent of surface roughness. The adhesion of 3-5 μm particles can be avoided by mixing of small particles of 0.5μm powder into 9μm powder.

S043013 表面研磨処理を施した鋼板表面へのシリカ粉体の付着・堆積挙動に関する研究([S04301]環境調和型の表面改質および薄膜コーティング(1))

S043013 表面研磨処理を施した鋼板表面へのシリカ粉体の付着・堆積挙動に関する研究([S04301]環境調和型の表面改質および薄膜コーティング(1))

Application of polyaniline/nylon composites coating for corrosion protection of steel

In this research, we investigated the corrosion inhibition properties of polished steel plates (low carbon) coated with a polyaniline (emeraldine base form) blend with nylon 66 (termed PANi/Ny) via cast method with formic acid as the solvent. Polyaniline (PANi) was prepared chemically from aqueous solution using aniline (0.2 M) as a monomer and ammonium persulfate (0.2 M) as an oxidant. The polymer powder produced was changed into emeraldine base (EB) form after treatment with dilute ammonia solution (0.5 M) in order to do further processing. The corrosion experiments were performed in the open circuit, exposing samples to different aggressive and corrosive conditions (e.g., NaCl, HCl). To produce a good comparison, the corrosion study was performed on both polymer-coated and bare-steel samples. Corrosion monitoring was performed by simple immersion tests and determination of the concentration of iron ions and metal weight loss in test solutions. It was found that PANi/Ny coatings can provide an anodic protection against corrosive environments in which the metals are exposed. The corrosion rate for the polymer coated steel was significantly lower than the bare steel (~10–15 times).

Ion-beam-assisted deposition of magnetron-sputtered metal nitrides

The refractory metal nitrides Ti-N, Zr-N, V-N, Nb-N, Ta-N, Cr-N, Mo-N and W-N and in addition the Al-N and Si-N systems were deposited with conventional d.c. magnetron sputtering and with ion-beam-assisted deposition on thermally oxidized silicon wafers and polished steel plates. It was possible to distinguish between three sets of materials related to their deposition conditions and coating properties. The deposition process and the coating properties were modified by the ion beam assistance. During the deposition the ion beam bombardment influences only the deposition rate because of the sputter loss. An influence on reactivity of magnetron sputtering by the ion beam bombardment was not observed. The ion bombardment leads generally to significant changes in coating properties, such as the tribomechanicai behaviour. These improved properties result from the dense microcrystalline structure.

A surface instability detection apparatus

A compression test apparatus for geomaterial, such as rock or concrete, samples that is designed to provide measurements of a stress displacement characteristics of the failure zone. A geomaterial formed into a specimen comprising a right rectangular prism is supported by walls along two parallel faces and a back face. An axial load is kinematically applied by a plate that is suitably guided for movement against the specimen which is supported on bottom support plate. All of the surfaces in contact with the specimen are lined with hardened and polished steel plates and lubricated to minimize friction. The assembly of the specimen and its supports is in a conventional loading frame so that an axial load can be applied to one end of the specimen and reacted against the bottom plate. Displacement transducers monitor the lateral displacement of an unrestrained side surface of the specimen.

Precipitation of actinides as fluorides or hydroxides for high-resolution alpha spectrometry

Management of radioactive wastes requires sensitive, accurate and reliable analytical procedures by which the radionuclides of interest can be determined in a wide variety of sample types. Procedures are given for precipitating and mounting all actinides from thorium through californium for high-resolution alpha spectrometry by two mutually complimentary systems. One system involves precipitation of fluorides from dilute acid in which most actinides can be separated from each other and from many common interferences by proper use of oxidizing and reducing agents. Elements forming strong fluoride complexes such as iron, titanium, zirconium, etc., do not interfere, but calcium interferes seriously. The other system involves precipitation of hydroxides from strongly alkaline solutions of ethylenediaminetetraacetic acid in which large quantities of calcium can be tolerated. More importantly, the latter system can be used to recover actinides coprecipitated with barium sulfate, which in turn permits use of potassium fluoride fusion to guarantee complete dissolution of the most refractory types of samples. Either system can be used to precipitate all actinides simultaneously to give a true gross alpha procedure. The resolution of the subsequent alpha spectra is typically 50 to 60 keV full-width-half-maximum with a 450 mm 2 detector at 25% counting efficiency which is almost as good as that obtained from sources prepared by electrodeposition onto polished steel plates. However, the procedures are much faster and generally give chemical yields greater than 98% much more reliably than are obtained with electrodeposition. Some results are given on the content of several actinides in ores, soils, mill tailings and other radioactive wastes. Also, some data and general conclusions are given on the leachability of transuranium elements from candidate wasteforms for long-term retention of radioactive wastes.

Determination of radium-226 in ores, nuclear wastes and environmental samples by high-resolution alpha spectrometry

Management of radioactive wastes requires sensitive, accurate and reliable analytical procedures by which the radionuclides of interest can be determined in a wide variety of sample types. The determination of radium-226 by alpha spectrometry has been investigated critically to determine the exact experimental conditions necessary to achieve these objectives. Refractory solids such as soils, ores, and tailings from uranium mills are dissolved completely by fusion with potassium fluoride in the presence of barium-133 tracer. The fluoride cake is then transposed with sulfuric acid to a pyrosulfate fusion with simultaneous volatilization of all silica and fluoride. Radium is precipitated with barium already present in the sample by addition of lead perchlorate to a dilute hydrochloric acid solution of the pyrosulfate cake. The resulting insoluble sulfates are dissolved in an alkaline solution of diethylenetriaminepentaacetic acid, and the radium and barium sulfates are reprecipitated with acetic acid in the presence of a seeding suspension to produce very small crystals to minimize self-absorption of the alpha particles in getting out of the crystal lattice. The precipitate is mounted on a membrane filter with 0.1-micrometer pores and analyzed by alpha spectrometry. Resolution is about 60 keV full-width-half-maximum which is much better than has been achieved previously from barium sulfate and is as good as is obtained with actinides electrodeposited on polished steel plates. Recovery is over 95% and accuracy is generally as good as the counting statistics obtained will permit. Inaccuracies caused by the differences between radium and the barium tracer and the severe contamination of the detector caused by recoil and volatilization of polonium-210 have been virtually eliminated. Some data on radium-226 in wastes and environmental samples and methods for its removal are presented.

Detection at a distance of laser-generated ultrasound using a confocal Fabry–Perot interferometer

A novel scheme to detect ultrasonic motion at the surface of a solid sample is presented. The surface of the sample is illuminated by a frequency-stabilized laser and the light scattered by the surface is received by a confocal Fabry–Perot interferometer, which demodulates the Doppler shift produced by ultrasound. Experimental results, obtained at a distance of 1.5 m from a machined but not polished steel plate, and excited by ultrasound produced by a laser pulse, are presented.

Optical detection of ultrasound at a distance using a confocal Fabry–Perot interferometer

A novel scheme to detect ultrasonic motion at the surface of a solid sample is presented. The surface of the sample is illuminated by a laser and the light scattered by the surface is received by a confocal Fabry–Perot interferometer which demodulates the Doppler shift produced by ultrasound. Experimental results, obtained at a distance of 1.5 m from a machined but not polished steel plate, and excited by ultrasound produced by a laser pulse, are presented.

The determination of the coefficient of dynamic friction of organic powder compacts on steel

A practical experimental model system has been successfully used to study the frictional response of organic powder compacts sliding across a polished steel plate, representative of the die bore of a production compaction system. This system offers a controlled approach to the study of frictional phenomena occurring during compaction and facilitates a more detailed investigation into the fundamental mechanisms of friction than a simple resolution of forces within a punch and die apparatus. For acetylsalicyclic acid sliding on steel, the dynamic friction coefficient was found to be dependent on the displacement and, to a lesser extent, the initial normal load, whereas for PTFE on steel, the dynamic friction coefficient was independent of displacement and load and estimated at 0.09. Thus, soft organic materials exhibit very different frictional characteristics to those of brittle materials. These differences reflect the differing importance and magnitude of the three frictional components, adhesion, shear and ploughing.

On the contact of smooth surface

In recent years a number of experiments have shown that if a clean optically polished plate is lowered on to a similarly polished plate in air, the two surfaces do not come into contact. The top plate remains “floating” at a distance equal to the thickness of several thousand air molecules above the bottom plate. Thus Hardy and Nottage found that a polished steel cylinder placed on a steel plate remained at a distance of 4 µ above the plate in clean dry air. By applying a pressure to the top cylinder the surfaces could be made to approach more closely, but on removing the pressure the cylinder would again rise to a height of 4 µ . This height remained constant and was the same for glass on glass as for steel on steel. When the air was replaced by various organic substances, e.g. , octane, capryllic acid, octyl alcohol, the distance between the surfaces remained remarkably constant at 4 µ . When the surfaces were contaminated with a trace of palmitic acid the distance was decreased to 2·3 µ . Similarly Watson and Menon using an electrical capacity method found that the distance between polished silver or polished steel plates in air or in oil was approximately 4 µ . Experiments made by Lee are consistent with this. A full discussion of this phenomena is given by Hardy, who considers it to be “the most difficult problem of the boundary state” ( loc.cit ., p. 2). The possibility that the top plate is supported on solid particles was considered in this paper, but the experimental evidence then available argued against it, and it was thought probable that the plate was supported by a film of air or of liquid. To explain this it would be necessary to postulate oriented chains of molecules extending from the surface for several thousand molecules. This is contrary to most physical evidence, which shows that the effect of a surface on a gas does not extend for more than a few molecular layers. The first molecular layer of gas may be oriented and strongly held by the surface, but the degree of orientation decreases very rapidly and becomes inappreciable at a distance of a few molecular diameters from the surface. The point was discussed with Sir William Hardy, and at his suggestion further experimental work was undertaken on this anomalous effect.

EXPERIMENTS ON THE RUSTING OF INSTRUMENTS IN STERILIZATION BY BOILING.

Every one knows that if steel instruments are sterilized by boiling in pure water, they become covered with spots of rust. It is usual to guard against this by adding to the water 1 per cent. of sodium carbonate. Some surgeons complain that this process gives no uniformity of result, their instruments sometimes coming out bright, and sometimes badly spotted. As the rusting is a simple chemic process, the results ought always to be the same if the conditions are uniform. The following experiments were made to ascertain the effect of boiling under different conditions. A quantity of thin polished steel plates, each one inch wide and two inches long, were made for me by a cutler. These were washed well in ether, and then soaked in a bath of ether for some hours to remove all oily matter from the surface. Also two plates of aluminium, each two inches