Die steel for hot deformation of copper and copper alloys

The possibility of using die steels (4Kh3N5М3F and 4Kh4N5М4F2) with adjustable austenitic transformation during operation for a wide range of operating temperatures (below the critical point A1 and above the critical point A3) is shown for hot deformation of M1 copper (up to 630 °С) and МNZh5-1 copper-nickel alloy (900-950 °C) with increased service life. During hot deformation of copper-nickel alloy МNZh5-1, the service life of matrices made of steel with adjustable austenitic transformation 4Kh3N5М3F was increased, compared to steel 3Kh3М3F. The studied forged steel 4Kh4N5М4F2 is characterized by an increase in hardness and strength threshold compared to H13 steel, after the use of extruder wheels (production of more than 60 tons of copper products). In order to facilitate mechanical processing by cutting the work piece during the manufacture of matrices from experimental steels, it was proposed to carry out partial recrystallization, namely, incomplete annealing at a temperature of 750±20 ºС, which made it possible to improve mechanical processing (cutting) for the manufacture of dies and large-sized parts such as wheels extruders.