The heat source causes highly non uniform temperature distributions across the joint and in the parent metals. Therefore, the thermal expansion and contraction during heating and subsequent cooling as well as material plastic deformation at elevated temperatures result in inevitable distortions and residual. [3] II. WELDING DISTORTION & CONTROL METHOD Distortion in a welded structure results from the non-uniform expansion and contraction of the weld metal and adjacent base metal during the heating and cooling cycle of the welding process. During heating and cooling in the welding process, thermal strain occurs in the weld metal and base metal near the welded zone.
[3] concluded that interface friction resulted in tremendous plastic deformation, which was beneficial for joint formation. Ni and Ye [4] found that very fine grain (～4.2 μm) distribution at the weld interface. However, the mechanism of ultrasonic welding is not clear due to the weld process was complicated dynamic process, and the influence of ultrasonic soften of materials on temperature rise and materials plastic deformation are not comprehensively understood by experiments study alone. Finite element method (FEM) can be used in simulate the physic phenomenon in the dynamic process, and was widely used in recent study. In the earlier simulations, the ultrasonic softening of materials is not considered in their models.
Introduction Metal forming is materials processing technique which has been one of the oldest techniques used for manufacturing. It plays an important role in modern manufacturing techniques. Metal forming allows us to produce a desired geometrical shape with any material required. It exploits the ability of material to flow plastically in solid state with little or no waste. Metal forming causes increase of the material strength by work-hardening, and also residual compressive stresses in certain regions of a component increases its life.
After nonstop pleading with my parents I finally got the approval to build a forge. For those who don't know what a forge is it is a pan or box that is heated with either propane or coal. My forge was fashioned from an old webster grill a piece of raingutter a shop vac and a touch of duct tape. To get used to using the forge and hammering, I started out with six inch by one half inch bolts, I flattened and twisted the bolts. I soon realized that I had lot more to learn and that I had barely scratched the surface of blacksmithing.
It is the process of joining of metallic components of similar or dis-similar material with the help of a cylindrical rotating tool. After the tool put into the rotation, due to friction between tool and workpiece, heat is generated which softens the material around the tool probe. The localized plastic deformation process occurring in the workpiece due to friction. The plastic deformation occurs at higher temperature, but lower than the melting point temperature of the workpiece. The tool softens both the components around the interface and mixes the softened material from both the components around the interface to provide bonding.
The resulting rough and brittle surface is also called the white layer. The challenge for the peening process is to remove the white layer and to improve the quality of EDM machined surfaces. Several investigations prove that the removal of the white layer and the heat-affected zone is possible by using SiC grains and certain other parameters. In addition, peening reduces the roughness caused by EDM and compensates the reduction of fatigue strength by introducing compressive stresses. As a conclusion, peening was found out to have definitely the potential to be applied under specific peening conditions in tool manufacturing to achieve improvements of tool surfaces in terms of strength and fatigue
Manufacturing of the metals it will leads to crack initiation and distortion. When stress reaches maximum, cooling process is done by simplifying layer by layer at finite element analysis[6]. The
4) Sintering has three stages namely, slow heating during burn off, a constant temperature period, and cooling after sintering. The non-uniform and non- steady heating and cooling can results into formation of non- equilibrium structures and composites. 5) The porosity in the die pressed mechanical induces structural heterogeneity hence the properties like ultimate tensile strength, and elongation are inferior to wrought materials. 6) Some thermal difficulties are experienced with low melting point metals such as Sn, Pb, Zn and Cd. During sintering the atmosphere in the furnace should be controlled to avoid the formation of oxides as oxide will have adverse effects on the sintering process and results in inferior quality
The process carried out using a CNC milling machine. The surface roughness, the microstructure of the burnished surfaces and the microhardness were observed so as to obtain the influence of the process
It was also shown that heating and quenching resulted in an increase in hardness but decrease in toughness, however this brittleness could be offset somewhat by tempering the metal after hardening. Introduction Understanding material properties is of vital importance in engineering. It is preposterous to build a bridge, a building or even an artificial limb