Experimental Study On Temperature Characteristics Of Abrasive Water Jet Cutting Surface

As a cold processing method,high pressure water jet technology is used more and more widely due to its advantages of clean environmental protection,no pollution,no thermal deformation,no heat affected zone,small processing stress and high processing flexibility in the cutting process.Because of its low temperature characteristics,it plays a vital role in the treatment of inflammable and explosive dangerous goods,rubber,natural fiber and other heat-sensitive materials.In this paper,the temperature variation law of high pressure abrasive water jet cutting metal was studied.Firstly,the machining mechanism of abrasive water jet and the main source of heat during the machining process are analyzed.It can be seen that abrasive water jet's erosion of objects is mainly caused by cavitation damage,water jet's impact,water jet's dynamic pressure,water jet's fatigue damage caused by water jet's impulse load,water wedge action,etc.Under different cutting conditions or for different kinds of materials,one or two of these functions can be particularly prominent and play a leading role,the other will be in a secondary position.In the cutting process of abrasive water jet,the heat mainly comes from the kinetic energy and internal energy of water,the kinetic energy of abrasive and the impinging friction grinding between abrasive particles and workpiece,among which the impinging friction grinding between abrasive particles and workpiece is the main source of heat.In order to explore the low temperature characteristics of high pressure water jet technology and obtain the temperature rise law of high pressure water jet technology,a series of high pressure abrasive water jet cutting experiments were carried out by single factor method.In the process of the experiment,the pressure is kept unchanged,only the target distance and the nozzle moving speed are changed,and the temperature is measured by using two ways of contact thermocouple and non-contact infrared thermal imaging device.The cutting experiments are carried out on plastic 6061 aluminum alloy and brittle AZ31B magnesium alloy with the same thermal conductivity respectively.The experimental results show that the temperature variation rules obtained by the two temperature measurement methods are similar.With the increase of target distance,the temperature increases gradually.With the increase of the moving velocity of the nozzle,the temperature also increases gradually,but the increase is not very large.The result of the temperature measurement of the thermal imager is much higher than that of the thermocouple,which is mainly determined by the principle of the two temperature measurement methods.