MICROWAVE WELDING

In the field of joining of metals research are taking place for innovative ideas to come. One such new idea is microwave joining. It is one of the newly developing and advanced technique. But the thing is most people are unfamiliar with this type of process. It is a kind of fusion welding using frequency of 2.54 GHz. Microwave technique uses microwave energy which interacts with the material at the joint interface. It can be transmitted, reflected or absorbed when interact with materials. For processing materials like glazing of sprayed ceramic composite surfaces microwave energy can be used.

Microwave energy is widely used in composite and ceramics because of its nature. The nature of composite and ceramics is that they absorb microwave. As metals tend to reflect microwave radiations less work is done in the field of metals. This method was experimented on mild steel and stainless steel as substrates. For joining butt joint is preferred as it is easy to handle. Substrates are surrounded by refractory brick after applying the interfacing material between the faces. When microwave comes in contact with charcoal, which is used to provide extra heating, it starts burning thus increasing the temperature at the joint. The faces of substrates get totally wet. The molten region coverts into a shape of joint after cooling at atmospheric situation.

Taguchi method was developed by Dr. Genichi Taguchi to improve the quality of manufacturing goods. It is also applied in engineering field. The quality engineering set by Dr. Taguchi in 20^th century was regarded as greatest achievement in engineering. In his concept he mainly focuses on engineering strategies which includes upstream and shop-floor quality engineering. In upstream method small-scale experiments and robust designs for large scale production is used while cost based real time system is used in shop floor technique. Three concepts where there in Taguchi’s philosophy. One was that quality should be planned into the manufactured goods. Best worth is achieved by reducing the deviation on or after the target. This was his second. The expenditure of quality should be calculated as a function of deviation from the standard and the losses should be measured system-wide was his third.

After doing the Taguchi’s method using L9 orthogonal array some results were obtained. The value of hardness is lower at 600 sec as the material doesn’t fuse properly than 700s and 800s. There is decrease in hardness due to excessive heat at 800s. The percentage of interfacing powder will result in proper fusion and less porosity will be observed. Since the hardness of the stainless steel base metal is higher than mild steel base metal the SS-SS joint has higher hardness. Among the three parameters, substrates has the major influence on the hardness followed by percentage Ni based powder used and time. Like that new technologies and ideas are coming in the field of welding and inspection. welding inspector course in kochi