Thermal and Metallographic Investigation for H13A and AISI1050 using Vortex Tube Jet Assisted (VTJA) Machining

Machining without the use of any cutting fluid is known as dry or green machining. It is becoming increasingly more popular due to concern regarding the safety of environment. Most industries apply cutting fluids/coolants when their use is not necessary. The coolants and lubricants used for machining represents 16–20% of the manufacturing costs, hence the unnecessary use of these fluids should be restricted. Moreover there are certain materials that are considered as difficult to machine, for machining of such materials dry machining is advisable. An attempt is made here to carry out study with dry, wet as well as dry machining using cold air stream coming out of vortex tube, and the work piece is analyzed thermally as well as metallographic ally. The results are promising and have shown better results for cold air machining using vortex tube. The machining is performed using two grades of materials namely H13A, and AISI1050 with carbide coated tools, with depth of cut of 0.2 mm, Feed rate fixed at 0.5mm/rev and cutting speeds of 250,400,600 rev on semiautomatic lathe machine. The tests are conducted with coolant, without coolant and with cold air stream as coolant, After the tests the thermal plots and metallographic study for hardness and surface finish have revealed that using cold air as coolant produces better surface finish while maintaining the tool tip and work surface at significantly lower temperatures. The same is being termed here as Vortex Tube Jet Assisted (VTJA) machining.