Effect of ductile cast iron tool with grooved polishing and die coatings on friction behaviour in flat strip drawing of A7075-T6 alloy strip with quick heating

Abstract. A7075 aluminium alloy, a heat-treatable aluminium alloy, is expected to be applied to automobile frame parts from the viewpoint of high strength and light weight. To form this aluminium alloy, hot stamping using quick contact heating with a hot plate has been developed. To prevent seizure caused by hot stamping, the frictional properties of different tool coatings under warm and dry conditions were investigated by drawing tests of aluminium alloy strips using quick contact heating. Diamond like carbon (DLC) showed a low coefficient of friction and prevented seizure. The warm forming process allows the use of liquid lubricants. The frictional properties of cast iron and a simple surface texturing technique, grooved polishing, were investigated under warm and liquid lubrication conditions. The cast iron with grooved polishing showed the reduction in friction equivalent to DLC and prevented seizure as well.