Testprocedur för undersökning av adhesiv förslitning vid svarvning

Sammanfattning: Adhesive wear in machining is caused by adhering through micro welding of workmaterial on the cutting tool, this may lead to the formation of built-up edge andbuilt-up layer. This is known as secondary adhesion, the wear mechanism mayalso lead to pieces of the tool coating being ripped of and following the chip, which is known as primary adhesion. The wear mechanism most often results in the deterioration of the cutting tool. The aim of this experimental study is toenable examination of the phenomena. The objective is to bring forth experimental equipment and measuring methods and procedures that can be used for this purpose. A method for examining the phenomena in turning was achieved using manual lathe and cemented carbide inserts of the type Sandvik “CNMG 12 04 08 -XM4325”, with a coating consisting of CVD Ti(C,N)+Al2O3+TiN. The inserts were marked at the rake face for reference in examination. The work material used wasthe quenched and tempered steel EN-34CrNiMo 6 and the austenitic stainless steel EN-1,4436. The cutting speed at which the adhesive wear is prominent in machining of these work materials, was determined by radial turning of the material ends. In order to remove the adhered work material, the inserts where cleaned with hydrochloric acid and ultrasonic washing. The inserts were examined with a scanning electron microscope (SEM) prior to and after cleaning. The results from the SEM examination show that the inserts have a spongy looking texture on the surface with craters and holes. By comparison of the surfaces between different engagement time with work the material, it was found that because of adhesive wear, the texture of the surface slowly changes. The changes consists of enlarging of existing craters and new ones being created. This result meant that the examination with SEM was deemed a good method for examining the phenomena. The results also showed that the texture of the surface could also be affected by the ultrasonic washing, which meant that this method of cleaning is not recommended. The recommendation is instead to bathe the inserts in the hydrochloric acid without the ultrasonic wash for 30 minutes.