Search Results

Abstract Transient temperature analysis is involved in the thermal simulation of the heat treatment process, in which the hot metal temperature changes with respect to time from an initial state to the final state. The critical part of the simulation is to determine the heat transfer coefficient (HTC) between the hot part and the quenching medium or quenchant. In liquid quenching, the heat transfer between the hot metal part and water becomes complicated and it is difficult to determine HTC. In the current experimentation a medium carbon steel EN 9 rod with a diameter of 50 mm and length 100 mm was quenched in water and ethylene glycol mixture with different concentrations. A part model was created; meshed and actual boundary conditions were applied to conduct computational fluid dynamics (CFD) analysis. In order to validate CFD analysis the experimental trials were conducted.

Abstract AISI H13 hot work tool steel is commonly used for applications such as hot forging and hot extrusion in mechanical working operations that face thermal and mechanical stress fluctuations, leading to premature failures. Cryogenic treatment was applied for AISI H13 steel to improve the surface hardness and thereby fatigue resistance. This work involves failure analysis of H13 steel specimens subjected to cryogenic treatment and gas nitriding. The specimens were heated to 1020°C, oil quenched followed by double tempering at 550°C for 2 h, and subsequently, deep cryogenically treated at −185°C in the cryochamber. Gas nitriding was carried out for 24 h at 500°C for 200 μm case depth in NH3 surroundings. The specimens were subjected to rotating bending fatigue at constant amplitude loading at room temperature.

Abstract This study aims to explore the wear characteristics of fused deposition modeling (FDM) printed automotive parts and techniques to improve wear performance. The surface roughness of the parts printed from this widely used additive manufacturing technology requires more attention to reduce surface roughness further and subsequently the mechanical strength of the printed geometries. The main aspect of this study is to examine the effect of process parameters and annealing on the surface roughness and the wear rate of FDM printed acrylonitrile butadiene styrene (ABS) parts to diminish the issue mentioned above. American Society for Testing and Materials (ASTM) G99 specified test specimens were fabricated for the investigations. The parameters considered in this study were nozzle temperature, infill density, printing velocity, and top/bottom pattern.

Abstract Super duplex stainless steel (SDSS) is a type of stainless steel made of chromium (Cr), nickel (Ni), and iron (Fe). In the present work, a 1.6 mm wide thin sheet of SDSS is joined using gas tungsten arc welding (GTAW). The ideal parameter for a bead-on-plate trial is found, and 0.216 kJ/mm of heat input is used for welding. As an outcome of the welding heating cycle and subsequent cooling, a microstructural study revealed coarse microstructure in the heat-affected zone and weld zone. The corrosion rate for welded joints is 9.3% higher than the base metal rate. Following the corrosion test, scanning electron microscope (SEM) analysis revealed that the welded joint’s oxide development generated a larger corrosive attack on the weld surface than the base metal surface. The percentages of chromium (12.5%) and molybdenum (24%) in the welded joints are less than those in the base metal of SDSS, as per energy dispersive X-ray (EDX) analysis.

Abstract TOC

Abstract TOC

Abstract Low-carbon equivalent austempered ductile iron (LCE-ADI) exhibits high modulus of elasticity than conventional austempered ductile iron (ADI) due to less graphite content. Austempering parameters of temperature and time significantly influence the mechanical properties of LCE-ADI. In the present work, response of the material to two-step austempering in the range of 350–450°C was studied, and a comparison was made to single-step austempering. Reduction in ferrite cell size, increase in % carbon in carbon-stabilized austenite (CSA) and increase in volume fraction of CSA led to increase in tensile strength (10%) and hardness (20%), in addition to improved toughness (10%).

Abstract This study investigated the influence of high-strength low-alloy steel on the fatigue life of a load-bearing member with a non-load-bearing transverse welded attachment (T-joint). It compared high cycle fatigue data to two fatigue design codes, namely BS 7608 and Eurocode EN 1993-1-9. Different base and filler material combinations of varying material strengths were investigated, resulting in a total of three different specimen configurations. Two material combinations had a high-strength steel (Strenx® 700 MC D) for the base material, with one combination having a matched filler material and the other having an undermatched filler material. The third material combination had a lower-strength steel (S 355 JR AR) for the base material, with a matched filler material. Tensile tests were performed to confirm the base material mechanical properties and weld quality of the manufactured specimens.

Abstract In this article, the effect of heat treatment on the microstructure and mechanical behavior of medium-carbon steel wire intended for the spring mattress is investigated using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), X-ray diffraction, Vickers hardness (Hv), and tensile strength. The results indicate that the microstructure elongation along the wire axis is observed with the bending and kinking lamellae at the deformation level of 57.81%, this change appears as a fracture in the microstructure and leads to an increase in hardness, tensile strength, and intensities of diffraction patterns. After heat treatment, we observed a redistribution in the grain, which is almost the same in the wire rod and drawn wires; indeed, this led to a decrease in hardness, tensile strength, and augmentation in intensities of peaks. The EBSD pole figures reveal the development of texture in the cementite slip plane (001).

Abstract Lubricant additives are the main means to improve the performance of lubricants. In this article, green and inexpensive layered kaolin were selected as lubricant additives, and the effects of the type of modifier, concentration, particle size of kaolin additives, and working temperatures on the tribological performance of lubricants were investigated. The results showed that the Span80 modifier can effectively improve the dispersibility and friction reduction effects of kaolin oil samples. Compared with kaolin oil samples without the modifier, the modified kaolin oil can reduce the friction coefficient by 40.9% and the wear spot diameter of the steel balls by 43.8%. The layered kaolin additive can significantly reduce the friction coefficient and wear of steel balls in lubrication, and the friction coefficient showed a trend of decreasing and then increasing with increasing kaolin additive concentration and particle size.

Abstract Articulated vehicles form an important part of our society for the transport of goods. Compared to rigid trucks, tractor-trailer combinations can transport huge quantities of load without increasing the axle load. The fifth wheel (FW) acts as a bridge between the tractor and trailer, which can be moved within the range to achieve rated front and rear axle loads. When the FW is moved front, it adversely affects the cab dynamics and cab suspension forces. Compared to the cab pitch and roll, yaw motion increases drastically. The current study tries to address this issue by providing reaction rod links in the rear cab suspension. In this study, a 4×2 tractor with a three-axle semitrailer is considered by keeping the FW at its frontmost position, which is the worst-case scenario for a cab. Three different cases of reaction rod arrangement and its influence on cab dynamics are studied in comparison with a model without reaction rods.

Abstract Prediction of the surface finish of hardened bearing steels was estimated in machining with ceramic uncoated cutting tools under various process parameters using two statistical approaches. A second-order (quadratic) regression model (MQR, multiple quantile regression) for the surface finish was developed and then compared with the artificial neural network (ANN) method based on the coefficient determination (R 2), root mean square error (RMSE), and percentage error (PE). The experimental results exhibited that cutting speed was the dominant parameter, but feed rate and depth of cut were insignificant in terms of the Pareto chart and analysis of variance (ANOVA). The optimum surface finish in machining bearing steel was achieved at 100 m/min speed, 0.1 mm/revolution (rev) feed rate, and 0.6 mm depth of cut.

Abstract The present investigation has been conducted to study the tribological and adhesion properties of X10CrNi18-8 austenitic stainless steel (ASTM 301) coatings deposited on aluminum alloys such as AU4G by using the arc-spraying process. These coatings were made with and without a bond-coat layer, which is constituted by NiAl. The structure of the phases that are present in coatings was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The measurements of microhardness and tribological behavior at different loads were also performed on the surface of the coatings. Adherence test was also carried out using four-point bending tests. The SEM showed that the dense microstructures of coatings have a homogeneous lamellar morphology with the presence of porosities and unmelted particles. The main phase of coating corresponds to a solid solution as a face-centered cubic (fcc).

Abstract With the introduction of advanced lightweight materials with complex microstructures and behaviors, more focus is put on the accurate determination of their forming limits, and that can only be possible through experiments as the conventional theoretical models for the forming limit curve (FLC) prediction fail to perform. Despite that, CAE engineers, designers, and toolmakers still rely heavily on theoretical models due to the steep costs associated with formability testing, including mechanical setup, a large number of tests, and the cost of a stereo digital image correlation (DIC) system. The international standard ISO 12004-2:2021 recommends using a stereo DIC system for formability testing since two-dimensional (2D) DIC systems are considered incapable of producing reliable strains due to errors associated with out-of-plane motion and deformation.

Abstract The objective of the study was to evaluate the quasi-static and fatigue performance of automotive anti-roll bars (ARBs) under extreme environmental conditions. Flexural quasi-static and fatigue tests of SAE 1040 steel were conducted above and below the ductile-to-brittle transition temperature (DBTT) in flexure and compared with their room temperature performance. The flexural strength increased by decreasing the temperature to −40°C. The fatigue lives are determined for stress levels of 87%, 60%, and 30% of their flexural strength under displacement mode in constant amplitude loading. Experimental stress versus the number of cycles (S-N) curves of SAE 1040 steel state that all tube specimens have fatigue limits that were more than 100,000 cycles at −40°C. The fatigue life of the SAE 1040 tube exhibited infinite life below the ductile-to-brittle transition (DBT).

Abstract The joining of dissimilar AISI 1020/AISI 1018 steel and AISI 431/AISI 1018 steel carries significant importance in automotive applications to lower the cost of manufacturing and obtain the mechanical properties of different materials. However, the joining of these materials by fusion welding is difficult particularly for a rod-to-plate joint configuration such as solidification cracking, wider heat affected zone (HAZ), HAZ softening, high residual stresses, and distortion of joint configuration. So, to overcome the issues in fusion welding of AISI 1020/AISI 1018 steel and AISI 431/AISI 1018 steel, rotary friction welding (RFW) was employed to develop the rod-to-plate joints. The parametric empirical relationships (PERs) were developed using regression equations incorporating RFW parameters to predict tensile strength (TS) and weld interface hardness (WIH) of rod-to-plate joints.

Abstract It is a consensus in academia and the industry that 2D digital image correlation (2D-DIC) is inferior to a stereo DIC for high-accuracy material testing applications. It has been theoretically established by previous researchers that the 2D-DIC measurements are prone to errors due to the inability of the technique to capture the out-of-plane motion/rotation and the calibration errors due to lens distortion. Despite these flaws, 2D-DIC is still widely used in several applications involving high accuracy and precision, for example studying the fracture behavior of sheet metal alloys. It is, therefore, necessary to understand and quantify the measurement errors induced in the 2D-DIC measurements. In this light, the presented work attempts to evaluate the effectiveness of 2D-DIC in mechanical testing required for the generation of fracture strain vs. triaxiality curve for sheet metal.

Abstract This article primarily focuses on studying and analyzing the effect of machining parameters, viz., pulse on time (TON), pulse off time (TOFF), and pulse current (Ip) on machining performance in terms of surface roughness (Ra) and material removal rate (MRR) during electrical discharge machining (EDM) of alloy tool steel (SKD11 steel). The traditional trial-and-error methods used to derive empirical relationship and optimize the process is time consuming and results in reduced productivity, high rejection, and cost. The response surface methodology (RSM) approach of design of experiment technique was applied for designing the experiments. The influences of EDM parameters on Ra and MRR were investigated using different graphs. The mathematical model equations for Ra and MRR were generated. The optimum parametric combinations for smaller Ra (highest surface finish) and highest MRR were found, and the optimized values of Ra and MRR were obtained.

Abstract Enhancing the performance of a ride-oriented algorithm to provide ride comfort and vehicle stability throughout different terrains is a challenging task. This article aims to improve the performance of the state-of-the-art continuous skyhook algorithm in coupled motion modes with an optimally tuned stability augmentation system (SAS). The tuning process is carried out using a chaotic map-initialized particle swarm optimization (C-PSO) approach with ride comfort and roll stability as a performance index. A large van model built-in CarSim is co-simulated with a C-PSO algorithm and control system designed in MATLAB. To realize the feasibility and effectiveness of the proposed system, a software-in-loop test is conducted on five complex ride terrains with different dominant vehicle body motion modes. The test results are compared against the passive system, four corner continuous skyhook control, and four corner type-1 fuzzy control.

Abstract TOC