Study On The Friction And Wear Behaviour Of Stainless Steel Rubbing Against Copper-impregnated Metallized Carbon Under Electrical Currents

Underground transportation is an effective way to resolve traffic jam in cities. The present running speeds of subway vehicles are increased continuously. With the increase of train running speeds and loads, the wear of contact wire/pantograph system becomes more and more serious. In the cases, the wear of steel aluminum composite conductor rail/collector shoe needs to be studied. Therefore, it is significant to study the wear with electric current for developing subway, high speed and heavy haul railway transportations.A series of experimental tests were carried out using stainless steel rubbing against copper based sintered alloy and copper-impregnated metallized carbon with electrical current on a pin-on-disc test rig. During the test, the friction coefficient and wear volume loss were collected. Various examinations on worn scars were performed by means of an Optical Microscopy (OM), a Hardness Tester, a Confocal Laser Scanning Microscopy (CLSM) and SEM. The effects of sliding speed, normal load and electrical current intensity on wear behaviour were studied in detail. Main conclusions can be drawn as follows:1. With increasing electrical current intensity, The wear volume loss and the friction coefficient of copper based sintered alloy increase. The wear mechanism of stainless steel against copper based sintered alloy couple is mainly attributed to adhesion,abrasion and oxidation.2. With increasing electric current intensity , the friction coefficient of the copper-impregnated metallized carbon/stainless steel couple decreases and becomes close to each other little by little but the wear loss rate of copper-impregnated metallized carbon increases. Under different sliding speeds, the wear loss rate of copper-impregnated metallized carbon has different change tendencies with increasing normal load.3. Without electric current, the wear mechanism of stainless steel against copper-impregnated metallized carbon couple is mainly attributed to light adhesion and abrasion. With electric current, the wear mechanism of this couple is mainly attributed to adhesion,abrasion,oxidation and electric arc ablation loss.4. When copper-impregnated metallized carbon connected with anode, its wear loss is less than that with cathode. Moreover, the oxidation occurring on worn surfaces of copper-impregnated metallized carbon with anode is heavier than that with cathode.5. Under the present experimental conditions, the wear losses of stainless steel are all light.