Prashant Date

Recycling-Cum-Manufacturing Process for Utilization of Finely Divided Ferrous Metallic Scrap

The issues of metallic scrap management and its utilization in manufacturing plants are nowadays intensely considered to address essential sustainability guidelines. Efficient recycling procedure for shop floor metallic scrap is not yet available because of abundance and contamination of nonmetallic constituents. Other ferrous metallic scrap are melted and purified during secondary steelmaking to get products in the form of blooms and billets are obtained. This study illustrates the potential of powder technology (powder metallurgy (PM) and metal injection molding (MIM)) based process for solid-state recycling and attainment of usable products. Industrially downgraded grinding sludge is pulverized and used as a raw material. Results showed properties of sintered parts are significantly improved due to in-situ reduction and densification during sintering. Recyclability Index (RI) was created to compare the effect of process variables on obtained products. Based on RI, recycled ferrous parts have about 70% comparable properties with equivalent pure iron parts. Complex reduction and sintering behavior in MIM, particularly, diffusion and pore volume kinetics limits applicability of MIM with this recycling approach. However, few industrial parts were developed and manufactured by PM based approach to validate the applicability of this novel recycling-cum-manufacturing process for the production of porous parts.

Ideal Flow Theory of Pressure-Dependent Materials for Design of Metal Forming Processes

The ideal flow theory for pressure-dependent materials is used to calculate an ideal die for plane strain extrusion/drawing. In particular, the double slip and rotation and double shearing model are adopted. Comparison with the available ideal flow solution for pressure – independent material is made. It is shown that the die for pressure-dependent material is shorter than that for pressure-independent material. Moreover, the angle of internal friction has an effect of the distribution of contact pressure.

Room Temperature Compression Behavior of Mixtures of Carbonyl Iron Powder and HDPE

In present research work, metal injection molded cylindrical samples containing the mixture of carbonyl iron powder and high-density polyethylene (HDPE) were compressed at various strain rates. Three mixtures of carbonyl iron powder and HDPE were prepared to contain 80 %( Material A), 86 %( Material B) and 92 %( Material C) metal powder by weight. Compression tests were performed on the cylindrical samples at different crosshead velocities of Universal Testing Machine varying from 0.6-25 mm/min. True stress-true strain behavior of these samples under uniaxial compression test was studied. Based on these curves, polynomial equations were formulated to describe the plastic deformation behavior of the various mixtures at various cross head velocities. The Material C samples showed higher strength as compared to samples from the other two materials. However, Material A showed superior deformation behavior.

Exploration and Analysis of Strain Softening Phenomena of L6 Steel

It is a necessity of modern forging industries to explore new materials for hot forging dies, which gives better quality of forging with extended fatigue life and less economic aspects. L6 Steel is one of the material for modern metal forming industries, which mollifies all the benchmarks and requirements. PreMature fatigue failure of forging dies is always an unpredictable and economical damage for any metal forming industry. L6 Steel is a high strength material to avoid die cracking during complex phenomenon of hot forming process. L6 steel, which when subjected to load, will get softened and this is strain softening. In this paper, numerous experiments have been carried on L6 steel material to evaluate cyclic Stress strain behavior of this material. This research leads us to evaluate and explain phenomenon regarding strain softening and its behavior during low cycle fatigue test. Low cycle fatigue test is carried out on MTS fatigue test machine at fully reverse loading condition R=-1. Also strain softening effect on forging metal forming process is explained in detail. The failed samples during low cycle fatigue test further investigated metallurgically on scanning electron microscopy. Material micro mechanisms further investigated by EBSD technique. Finally the study concludes that, strain softening phenomenon plays a vital role in the fatigue failure of metal forming dies.

Life prediction of l6 steel using strain-life curve and cyclic stress-strain curve by means of low cycle fatigue testing

L6 Steel is used as die material in closed die hot forging process. This material is having some unique properties. These properties are due to its composition. Strain softening is the noticeable property of this material. Due to this in spite of cracking at high stress this material gets plastically deformed and encounters loss in time as well as money. Studies of these properties are necessary to nurture this material at fullest extent. In this paper, numerous experiments have been carried on L6 material to evaluate cyclic Stress - strain behavior as swell as strain-life behavior of the material. Low cycle fatigue test is carried out on MTS fatigue test machine at fully reverse loading condition R=-1. Also strain softening effect on forging metal forming process is explained in detail. The failed samples during low cycle fatigue test further investigated metallurgically on scanning electron microscopy. Based on this study, life estimation of hot forging die is carried out and its correlation with actual shop floor data is found out. This work also concludes about effect of pre-treatments like nitro-carburizing and surface coating on L6 steel material, to enhance its fatigue life to certain extent.

Novel Design of Valve Stem to Eliminate Buckling

Acceptable variations in the length of the valve stem, in a conventionally manufactured valve, give room to the possibility of the stem to buckle and get jammed in the guide. Salvaging such a situation is expensive and time consuming. The present paper addresses this problem by increasing the compliance of the valve stem by introducing holes in it. The desired elastic deformation along the length, however, causes transverse deformation, which needs to be minimized. The use of multiple holes helps achieve this. Taguchi Method based Design of Experiments using L25 orthogonal array has been used for performing the parametric design to arrive at the best settings of the 5 parameters. The optimal settings eliminate the buckling and thus make the operation of the valve stem robust against manufacturing variabilities.

On The Experimental Verification Of The Numerical Simulation Based Inferences From Strain Distribution In Axisymmetric Drawn Sheet Metal Parts

Studies based on numerical simulations of axisymmetric parts showed that the scaleability of strain distribution as described above was limited to only about 60% geometric upscaling in conventional forming of a cylindrical part and to about 90% upscaling in hydroforming. These findings may be criticized as they amount to verification of the scaleability of the differential equations being solved.In this context experiments were performed on cylindrical sheet metal cups drawn to three different diameters keeping the draw ratio as well as the R/t ratio at the die entry and the punch nose constant. The meridional strain distribution was determined using GOM automatic strain measuring system. The strain distribution was fitted into a Fourier series and the variation of the Fourier coefficients with punch travel plotted for the three sizes investigated. This variation in the major Fourier coefficients was found to run parallel indicating scaleability of the strain distribution. An attempt was made to predict t...