Mild Steel Pieces Research Articles

The Effect of Surface Roughness of Low Carbon Steel by Heat Treatment in Turning Operation

This research focuses on enhancing the surface roughness of low carbon steel by heat treatment of low carbon steel in turning operation. Heat treatment is mainly used to improve the mechanical properties of materials. Two sets of specimens used during the experiment where each has 5 pieces of mild steel that heat-treated of two-level of temperatures of 650 oC and 900oC. After the heating process of all specimens, it will be exposed to different coolant media which are quenching, normalizing and annealing. A carbide single-point tool, one level of cutting parameters selected as one level of cutting speed and depth of cut and two levels of feed rate used during this research. The results show that specimen quenched by oil bath measures the highest value of the surface roughness of 8.26 µm at 900oC and machined with a feed rate of 0.113 mm. While quenched water specimens show less surface roughness of 4.91µm at 650oC in the same feed rate.

Experimental study of mild steel weld bead mechanical properties in rotational arc welding process

Abstract In the present study, mild steel pieces of 6 mm thickness are welded by conventional and rotational gas metal arc welding by means of the filler metal ER 70S-6 and inert gas is carbon dioxide. The welding voltage, current and welding speed are chosen as 25 V, 150 A and 0.18 m/min respectively. The rotational arc welding is done at different rotational speeds of 150 rpm and 180 rpm respectively. The tensile strength, hardness, penetration, and microstructures are measured for each specimen after the welding process. From the experiment it is observed that increasing the rotational speed improves the mechanical properties.

Automated and programmable electromagnetically actuated valves for microfluidic applications

In this paper, we report the design and development of easy-to-fabricate, low cost electromagnetically actuated ON/OFF valves to control multiple fluids on a programmable microfluidics platform. The valves were fabricated using mild steel pieces glued onto a PDMS membrane and its deflection was effected by using an array of solenoids. The activation of solenoid array was controlled using a programmed microcontroller. Numerical studies were carried out to optimize design parameters such as the distance between the valve and the solenoid, membrane thickness and the diameter of the deflection zone. The deflection of the valves was also studied using a high-speed digital camera and the results were in good conformity with the simulation results. Deflections up to 1200 μm could be achieved with a response of 3 ms. The efficiency of the developed platform for controlling multiple fluids was verified by experimental studies using coloured solutions and biosensors.

Analysis of Favorable Process Conditions for the Manufacturing of Thin-Wall Pieces of Mild Steel Obtained by Wire and Arc Additive Manufacturing (WAAM)

One of the challenges in additive manufacturing (AM) of metallic materials is to obtain workpieces free of defects with excellent physical, mechanical, and metallurgical properties. In wire and arc additive manufacturing (WAAM) the influences of process conditions on thermal history, microstructure and resultant mechanical and surface properties of parts must be analyzed. In this work, 3D metallic parts of mild steel wire (American Welding Society-AWS ER70S-6) are built with a WAAM process by depositing layers of material on a substrate of a S235 JR steel sheet of 3 mm thickness under different process conditions, using as welding process the gas metal arc welding (GMAW) with cold metal transfer (CMT) technology, combined with a positioning system such as a computer numerical controlled (CNC) milling machine. Considering the hardness profiles, the estimated ultimate tensile strengths (UTS) derived from the hardness measurements and the microstructure findings, it can be concluded that the most favorable process conditions are the ones provided by CMT, with homogeneous hardness profiles, good mechanical strengths in accordance to conditions defined by standard, and without formation of a decohesionated external layer; CMT Continuous is the optimal option as the mechanical properties are better than single CMT.

Limitations of the use of concrete bulk resistivity as an indicator for the rate of chloride‐induced macro‐cell corrosion

An experimental setup was designed to study the impact of concrete bulk resistivity on the rate of chloride‐induced reinforcement corrosion. Small pieces of mild steel were used to simulate pits (anodes) that form when chlorides come into contact with the reinforcement. The galvanic current was measured between the simulated anodes and a large cathode network. Comparisons were made between the corrosion rates calculated from the galvanic currents and the bulk resistivity. The bulk resistivity was varied using two mortar mixes (made of plain Portland cement and a Portland cement—fly ash blend), which were exposed in different temperature and moisture conditions. Despite a high scatter in the results, it was clear that the relationship between bulk resistivity and corrosion rate depended on the mortars tested. The findings presented in this article and the accompanying work strongly indicate that bulk resistivity alone does not provide sufficient information for assessment of the corrosion rate for chloride‐induced macro‐cell corrosion.

Performance and exergy analysis of a double-basin solar still with different materials in basin

Distillation efficiency and productivity of the passive single-basin solar still is very low. In this work, an additional basin is incorporated in the double-slope solar still to enhance the distillate output and to reduce the thermal energy losses. For further improvement in the productivity, different materials were used in the basin. Wick materials such as jute cloth, waste cotton pieces and black cotton cloth were used to increase the evaporation area. In addition to increase the heat storing capacity, mild steel pieces were used in the basin as energy storing materials. An exergy analysis was carried out to explain the effect of different materials on the exergy evaporation rate and exergy efficiency of the single- and double-basin solar stills. It shows that the basin with mild steel pieces has a maximum exergy efficiency of 2.072 and 1.412% for double- and single-basin stills, respectively. A payback analysis also conducted to prove the benefit of the double-basin still.

Performance of an inclined solar still with rectangular grooves and ridges

This work investigates the experimental performance of a new type inclined solar still with rectangular grooves and ridges in absorber plate. The still was fabricated and tested for various inclination angles of 25°, 30° and 35° facing south with absorber plate. Performances of the still were compared with different wick materials (Black cotton cloth, Jute cloth, and Waste cotton pieces) on the absorber plate. The effect of placing porous material (Clay pot) and energy storing material (Mild steel pieces) in the grooves were studied. The results demonstrate that 30° inclination is optimum which yielded 3.77 L/day production. Compared to different wick materials, black cotton cloth helps to achieve maximum productivity of 4.21 L/day. The addition of permeable materials and energy absorbing materials also enhances the distillate output to 4.27 L/day.

Comparative study of double basin and single basin solar stills

This paper presents a new approach to enhance the productivity of a solar still by introducing an additional basin in the double slope solar still. Two solar stills, single basin double slope and double basin double slope with the same basin area were fabricated and tested at Kovilpatti (9° 11′N, 77° 52′E), Tamil Nadu, India. The experiments were conducted with various depths of water, different wick materials, porous material and energy storing material. In double basin still, a mass of water in upper basin is constant for all experiments. For both stills, water production decreases with increase of water depth. The production rate is higher for both the stills, when mild steel pieces are used as storing material in the basin. For the same basin condition, double basin still production is 85% more than single basin still.

Correlation between corrosion rate and AE signal in an acidic environment for mild steel

The AE method is an effective technique for inspecting corrosion damage of mild steel, such as tank bottom floors. However, the correlation between AE signals and corrosion behaviour for mild steel has not yet been fully clarified. In the present study, the authors considered that the corrosion regions of bottom floors become a strong acid environment by Cl −, as reported in a previous study. Thus, the polarization resistance for the test pieces of mild steel was measured with an AC impedance method under a strong acid environment. It was clear that the polarization resistance indicated the corrosion rate for a test piece of mild steel in the experiments. While measuring the AE signals, the corrosion rate was monitored with a test piece. As a result, the AE signal showed good correlation with the corrosion rates of the test pieces. The corrosion behaviour of the test pieces was then discussed with the corrosion potential measured during the experiments. Furthermore, the cathode current was changed to control the generated hydrogen gas volume. The volume of the hydrogen gas generated from the cathode reaction was correlated to the AE signals.

The Accelerating Action of Calcium Thiosulfate on the Hydration of Portland Cement and Comparison with Other Inorganic Salts

Calcium chloride is now regarded as an excellent accelerator to the hydration of portland cement, however, its corrosive character to the steel in reinforced concrete is hardly ignored. Therefore, the accelerators without corrosive character are especially indispensable for concrete practice.In this paper, the accelerating action of calcium thiosulfate discovered or by the authors is investigated, in comparison with other inorganic soluble salts, by means of various methods.The accelerating ability of calcium thiosulfate on the setting of portland cement is very identical to that of calcium chloride. The early development of strength of portland cement increases in proportion to the amount of calcium thiosulfate added to portland cement. The early strength of mortar of portland blastfurnace slag cement (granulated blastfurnace slag 65%, portland cement 35%) is developed near that of ordinary portland cement, when calcium thiosulfate was used at the concentration of 3%. However, the accelerating action of calcium thiosulfate on the development of early strength of portland cement is slightly poorer than that of calcium chloride.The most characteristic of calcium thiosulfate as an accelerator will be that calcium thiosulfate does not give any corrosive action to the steel in concrete. The results of corrosion test showed that the test pieces of mild steel buried in mortar containing respectively 2% and 5% of calcium thiosulfate were scarcely corroded after the mortars were exposed under the atmosphere of outdoors for 6 months. Under a same condition, the test pieces of steel buried in the mortar containing 2% of calcium chloride was markedly corroded after only one month. Calcium nitrate did not show corrosive action. However, calcium nitrate can not be regarded as an accelerator.The heat liberation curves of the hydration of portland cement obtained by the use of a devised adiabatic calorimeter indicated that the accelerating action of inorganic salts on the hydration of portland cement is focused on the hydration of alite phase. The orders of effectiveness of anions and cations as accelerators of the hydration of portland cement are Cl->S2O3-->SO4-->NO3-, Cl->Br->I- and Ca++>Mg++>Na+.The hydration products of tricalcium silicate is CSH (II) when calcium chloride was present, is CSH (I) when gypsum was present and is not evidently identified when calcium thiosulfate was present. DTA curve of the 24 hours hydration product of C3S paste (H2O/C3S:50%) with 3% of calcium chloride showed a sharp exothermic peak at 640°C. The peak showed that the produced CSH (II) in hydration products was converted into β-C2S by heating. In the case of calcium thiosulfate, the continuous two exothermic peaks were obseved in DTA curve. The first peak could not be exactly assigned, however, the second was assigned as the oxidation of calcium sulfite which produced by the decomposition of calcium thiosulfate.

Synthesis of Some Methyl-10, 11-diaryl-undecanoates and 11-Aryl-9-undecenoates and Their Activity as Antioxidants and Corrosion Inhibitors

Methyl 10-undecenoate and mercuric acetate were reacted in methanol to give methyl methoxyacetoxy mercury-undecanoate. The mercurial adduct was then reacted with phenol, o-cresol, m-cresol, p-cresol and o-tert-butylphenol in 1: 5 mole ratio each at 60 °C for one hour in the presence of perchloric acid as a catalyst, giving methyl 10, 11-diaryl undecanoates corresponding to the respective phenols. The reaction of the mercurial adduct and 2, 6-di-tert-butylphenol gave methyl 11- (hydroxy, di-tert-butylphenyl) 9-undecenoate instead of methyl 10, 11-diaryl undecanoate. The mercurial adduct was then reacted with methyl benzoate, dimethyl phthalate, and methyl acetylsalicylate at the same reaction condition for 2 hours, giving methyl 11-methoxycarbonylphenyl-9-undecenoate, methyl 11-dimethoxycarbonylphenyl-9-undecenoate, and methyl 11-acetoxymethoxycarbonylphenyl-9-undecenoate. All diaryl undecanoates listed above showed antioxidant activity for methyl oleate at 40 °C and 100 °C. However, their activities are somewhat less than the activity of BRA. They were found effective as corrosion inhibitors by the water-dip method with a sample of turbine oil and test pieces o mild steel, aluminium, zinc and brass at the concentrations of 0.2, 0.4, 0.6 and 0.8%. Especially, the derivatives from p-cresol and o-cresol were excellent as corrosion inhibitors. Methyl 11-methoxycarbonylphenyl-9-undecenoate, methyl 11-dimethoxycarbonylphenyl-9-undecenoate and methyl 11- (acetoxy, methoxycarbonylphenyl) -9-undecenoate were converted to its sodium, calcium, strontium and barium soaps, and their activity as corrosion inhibitors was tested with a sample of turbine oil and test pieces of mild steel at the concentrations of 0.2, 0.4, 0.6 and 0.8% by the water-dip method. Regerding the acid components, the activity was ranked in the order of 11- (hydroxy, carboxyphenyl) -9-undecenoic acid>11-dicarboxyphenyl-9-undecenoic acid>11-carboxyphenyl-9-undecenoic acid. As for the base components, strontium and barium soaps were very effective followed by calcium soaps, sodium soaps being slightly less effective.

Instruments and Equipment for Testing

Just after the turn of the century, after many struggles, the heavier-than-air flying machine first rose from the earth, part of the success being due to the development of the comparatively light internal combustion engine. The materials of the airframe being mainly wood, including bamboo, and a few pieces of mild steel plate.For a few years the materials of construction altered only a little and the knowledge of those materials and their behaviour was limited and confined to that which had been established during the course of mechanical engineering.The mechanical engineers had been able to include fairly substantial factors of safety in their calculations which covered many variations and possible errors in materials, loads and workmanship and also—probably unknowingly —problems which could arise from fatigue.

包装材料の腐食作用に関する研究 (第3報)

Kraft papers containing various amounts of Cl- and H+ were prepared in laboratry. A piece of the papers was put between two pieces of mild steel and the corrosive was tested under 40°C, 90% R. H. and room temperature. Corrosive action was evaluated by the measurement of rust degree of iron and steel specified by Japanese Industrial Specification.Results obtained were as follows:1) The allowable limit of Cl- is about 0.4mg per 1g of material and beyond the limit, a proportional relation between Cl- concentration and R was established, where R is rust degree of mild steel.2) The allowable limit of H+ concentration is approx. 6 in pH and in acid range, log R is proportional to pH value.

軟鋼の腐食疲労に対する防食の効果

The propeller shaft of ship is normally insuarated electrically from ship's hull while in running. Under such condition the effect of galvanic anode on ship's hull can not be expected act to prevent galvanic corrosion on propeller shaft. It is the fact that most of all damages of propeller shaft commonly caused by the corrosion fatigue, and this kind of damage was mostly caused by such electrically insurating effect. On this point of view, we tried some torsional fatigue tests on mild steel pieces immersed in salt water which protected cathodically with impressed currents. With our results, the effect of protection showed increasing in corrosion fatigue strength than the one without protection.The rate of current density which need for complete prevention of corrosion for steel plate statically immersed in salt water is commonly agreed with about 150mA/m2. To compare with this, our results of torsional fatigue tests showed much more current, say 700-800mA/m2 were needed.With such point of view, we can expect that the damage of propeller shaft and corrosion of propeller can be prevented mostly with the application of cathodic protection directly on the shaft under the current density of some little above 800mA/m2.

The Initiation and Propagation of Fatigue Cracks in Mild Steel Pieces of Square Section

SummaryAn investigation has been made to determine the positions and directions of initiation and the directions of propagation of fatigue cracks and to examine the correlation between these positions and directions and the planes on which maximum tensile and maximum shear stresses are generated.To afford as wide a range as possible of the ratio of maximum shear stress to maximum tensile stress, tests have been made under combinations of alternating bending and torsion; and in order to separate partially the regions of high shear stress from those of high direct stress, the tests have been made on pieces of square section with the plane of bending parallel to one diagonal of the section. Two series of tests have been made; one a preliminary series on pieces having no parallel portion and the other on pieces having a parallel portion about three times the length of the side of the square section. The positions and directions of initiation and the directions of propagation of fatigue cracks have been observed and compared with the positions and directions of the maximum tensile and shear stresses.Fatigue cracks may be initiated as a result of either high shear stress or high tensile stress and in the present series of tests on mild steel, cracking in tension has occurred in preference to cracking in shear when the ratio of the tensile stress range to the shear stress range has exceeded about 1.6; for values of this ratio less than 1.6, the cracks started in shear (and vice versa); propagation along the plane of maximum shear appears to be preferred up to a slightly greater value of the tensile/shear ratio (about 1.7 possibly). The general direction of a crack formed as a result of high tension usually follows the plane of maximum tension and that of a crack formed as a result of shear usually follows the plane of maximum shear. In detail both types of crack—in this mild steel—deviate quite widely from their general directions but this deviation bears no obvious relation to the microstructure of the material. Cracks propagating along one plane of maximum shear occasionally show a marked tendency to branch along the associated plane of maximum shear; but this tendency is not always observed and in other cases no tendency to branch has been noted.

機械振動型自動放電加工に關して

Researches on "electric spark machining" by mechanically up and down vibrating electrode were made with the circuit used by Dr. B. R. & N. I. Lazarenko (U. S. S. R) (fig.1). As shown in fig.2, the vibrating electrode and its holder are nearly balanced with a counter-weight, so with the advance of machining, the vibrating center of electrode, i. e. its holder, descends automatically, and machining is made automatic simply. With this automatic machine, the conditions to raise the machining speed were sought, when the work pieces of mild steel were machined in a dielectric fluid bath of petrol chiefly. The main results obtained are as follows.(1) The smaller the sectional area of electrode is, the shorter the necessary working time becomes.. So it is preferable to use a hollow electrode. And it is otitable that the wall of electrode is made 1. 5mm thick. (fig.3 & 4)(2) The maximum working speed can be obtained, if the counter-weight is adjusted so that the mean working current may show 30, -40% of the short current Vo/R (fig. 5).(3) The greater the frequency of electrode vibration is, and the smaller the amplitude of electrode is, the faster the machining speed becomes (fig. 6). By this fact, the machining efficiency may be better, when the electrode is not vibrated.(4) Unless "arc discharge" takes place, the smaller the resistance R in charging circuit is, the faster the working- speed becomes (fig.7).(5) For the electrode material, brass is the best, and copper follows (Table. 1).(6) For the dielectric fluid, whale oil, petrol and rape-oil are good, but from the view point of easy filtering of used oil, petrol is the best, and water is also useful economically (Table. 2).