Development and Parametric Optimisation of Pure Magnesium Matrix Surface Composite by Friction Stir Processing

Friction stir processing (FSP) is an emerging method for improving surface properties of materials by composite fabrication. This study aims at optimizing the major FSP parameters and analysis of their real-time influence on the mechanical performance of a surface composite fabricated with Magnesium (Mg) matrix and Titanium Carbide (TiC) as reinforcement. Effects of different process parameters, tool rotational speed, plunge depth, the linear speed of the tool, cooling condition, and number of FSP passes have been examined. Using L27 array, a total of 27 combinations of these process parameters were analyzed by taking microhardness as an output response to find influential parameters by Taguchi's technique. Maximum micro-hardness was achieved when tool rpm of 600, cooling temperature of -10o C, tool feed of 15 mm/min, plunge depth of 0.35 mm, and 3 passes of FSP tool were chosen with the help of Taguchi's method. Analysis of variance indicated that cooling temperature, the tool feed, and the number of passes of the FSP tool were the most significant parameters.

Analysis of Hot Stamping Tool Cooling System—A Case Study

One of the important steps in the design of hot stamping tools is the analysis of their cooling system. This article presents an authorial, two-stage approach to solving this problem. The first stage consisted of a series of simulations of the hot stamping process in the Autoform package, with initial selection of shape and arrangement of cooling channels. These results allowed for the design of the tool for which the coupled thermal-flow analysis was carried out. The correctness of the adopted design assumptions has been confirmed by experimental tests. A trial series of drawpieces made in production conditions meet the requirements for hardness, mechanical properties, and appropriate microstructure. The presented procedure has become the practice of the drawpiece producers.

Abrasive tool design based on automated monitoring data of grinding

An automated measuring complex (AMC) “Grinding” developed, manufactures and approbated is described, which solves a problem of grinding process monitoring at all stages of abrasion and gives an opportunity to carry out an adjustment at all stages of an engineering process taking into account both the properties of an abrasive tool, cooling engineering mixtures, and also machining modes. The principle of the automated system operation is based on the statistical analysis of output energy data of manufacturing equipment operation.

Mechanical Properties and Microstructure of Dissimilar Friction Stir Welding of Pure Aluminum to Low Carbon Steel

The purpose of this research is to use friction stir welding (FSW) to join dissimilar metals, annealed low carbon steel and A1050 pure aluminum. A butt joint with a similar sheet thickness of 1.9 mm was applied. The novelties of the research are relatively using high generated heat produced by a combination of low traverse speed and high rotational speed to perform the dissimilar joints and using a tool material (K107cold work tool steel) which has not been used in FSW with tool cooling. The present work studied the effect of FSW variables such as tilt angle, tool cooling, base metal location on mechanical properties. Tensile tests were used to evaluate the mechanical properties of the dissimilar joints. The microstructure specimens were examined using a scanning electron microscope (SEM). Sound dissimilar joints were successfully produced. The maximum joint efficiency obtained in this study is 51.7% of the aluminum tensile strength. The microstructure images showed that many steel fragments were sheared off from the steel surface by the tool action and scattered in the weld nugget, a continuous intermetallic compound (IMC) layer formed at the interface, the thickness of the IMC layer at the interface decreased in the thickness direction of the weld. FeAl3 IMC phase was only observed at the interface.

Low Speed Orthogonal Machining of Pre-Heated FCC:BCC Alloys

Cocquilhat’s first documented (1851) how heat in a tool shortens the life of the tool. Research since his time has generally concluded that the tool gives up a relatively higher percentage of it’s “cold hardness and toughness” as compared to the work stock. This paper looks at the previously unstudied advantages/disadvantages which may be gained by pre-heating the work stock to a relatively modest temperature, thereby preferentially shifting the ratio/percentages back toward the tool. A widely-used body centered cubic (BCC) steel and a widely-used face centered cubic (FCC) aluminum were chosen to test common commercially machined crystalline structures. The materials were heat treated and/or aged to provide various levels of hardness within the crystalline structures. The selection of two cutting speeds, two levels of cut and three tool rake angles completed the factor level combinations chosen for the study. Parts were preheated immediately prior to the machining operations with an additional resistance heater mounted in the work holder to maintain the temperatures during the trial run. Tensile specimens of all the samples were undertaken to establish the cold working flow stress values of the materials tested. Machining was conducted in a specially modified Cincinnati Horizontal Milling machine using an improved Videographic Quick Stop Device (VQSD) to capture the geometry of the cutting formation simultaneously with the forces in the X, Y and Z-axes using a standard Kistler force plate dynamometer. Utilizing the VQSD greatly increases the number of replicates available for statistical analysis by the metal cutting researcher. This allows for comprehensive multivariate analysis of the data with high confidence (> 95%) in the obtained results. Forces and geometry were collected and analyzed. Wear was measured on the face of each tool using surface profilometers and white light microscopy. The specific horsepower (HPs), also known as the specific cutting energy, normal force (N), and wear rate data indicated there is a definite advantage to be had in pre-heating the workpiece by even a modest amount. In fact, the temperature was a significant prime factor (p-value <= 0.0001, Fstat > 5 with 95% certainty) in all factor level combinations. It was often ranked as the primary number one factor or the number two ranked factor. Many interactions with the temperature were also significant. This, combined with improved tool cooling methods, should result in all tools living a longer time while undergoing less chatter and/or deflection.

Alternative Temperature Control of Closed Forging Dies Using Heat Pipes

The temperature of forging dies has a high influence on the wear development of the tool surface. To reduce the thermal impact on tool life cooling lubricants are used in many manufacturing processes. They perform two functions: tool cooling and reduction of friction. Cooling lubricants must always meet these two requirements. Within this article the separation and the particular optimization of both functions is presented.As an alternative to a graphite-water-mixture, boron nitride is the medium of choice for lubrication purposes, since it features excellent lubricant properties. For a high wettability it is applied by electrostatic coating.As an alternative approach to removing heat from a forging die, the usage of heat pipes is for the first time investigated in this paper. These passive elements are able to transport heat without using external energy. They will be varied in form and volume. This cooling method will be qualified for the use in forging dies.