Effect Of Manufacturing Processes On Mechanical Properties Lecture Notes PDF

**Lecture - 08** **Effect of Manufacturing Processes on Mechanical Properties** There are 4, 5 mechanisms which significantly affect the mechanical properties **1 work hardening or strain hardening** increase in strength and hardness due to the strain hardening large number of the dislocations...

**Lecture - 08** **Effect of Manufacturing Processes on Mechanical Properties** There are 4, 5 mechanisms which significantly affect the mechanical properties **1 work hardening or strain hardening** increase in strength and hardness due to the strain hardening large number of the dislocations in the metal reduction in ductility and the toughness of the metal due to the work hardening. normalizing, basically refinement of the grain structure or like pearlite, ferrite etc. needs to the increase in strength and the hardness of the steel but without much compromise with toughness and ductility both. Martensitic transformation takes place then it will be leading to the increase in hardness and strength fine grain structure results in the increased strength, hardness, ductility and toughness Grain refinement only method which increases the strength and hardness without compromising the toughness and ductility sand is of the lower thermal conductivity poorer mechanical properties metal thermal connectivity finer grain structure better mechanical properties (die casting) pure metals they are soft and ductile casting properties are affected by the two aspects 1. Soundness 2. micro structural(planar, cellular, dendritic and equiaxed) better strength and hardness in case of the cellular and it is strong, but of the low ductility equiaxed one offers very good combination of the mechanical property bulk deformation based processes(rolling, extrusion,forging, wire drawing etc)- strength to weight ratio of the product can be improved **machining** very thin layer of say 50to 100 micrometer(μm) is left at the surface after removal of the material in form of the chips(shearing) two heat based, heat related effects softening or hardening. Softening due to the reversion or coarsening of the grain structure or hardening due to the transformation hardening related with the material for the heat treatable systems **Lecture - 09** **Break Even Analysis in Manufacturing Processes** **Lecture - 10** **Casting: Introduction and suitability** Components may be from very simple shapes to very complex shapes resistance heating furnaces can be used for melting the low melting point metals like magnesium, zinc and aluminum arc furnaces for melting the high temperature metals like steels and the cast irons coal fired furnaces cast irons being of the low melting point like say 1050 to 1150 C high specific heat metals -increase in the fluidity high thermal conductivity-misrun means incomplete filling of the mold cavity (affects the fluidity and the solidification time. It also affects the riser design and gating and riser design) tensile residual stresses(thermal expansion coefficient related )-the mould for making the internal cavity if this core does not collapse then it leads to the tensile residual stresses or if the design of the casting is such that it resists the shrinkage which is taking place then also tensile residual stresses will be taking place tensile residual stresses -distortion(rapping), hot tearing hot die casting process - low melting point metals zinc, lead and tin cold die casting-high temperature metals like aluminum, copper and the cast irons affinity to the atmospheric gasses\-\-\-\--impurity formation\-\-\-\--filtration requirement\-\-\--affects the pouring designed\-\-\-\-\-\-\-\-\--impurities can be filtered out and it also affects the gating system design. **Lecture -- 11** **Steps of Casting Process** Casting-fastest way of achieving the final shape