DIE STEEL 4Х4Н5М4Ф2 FOR HOT DEFORMATION OF COPPER

Purpose. Obtaining forged die steel (4Х4Н5М4Ф2) with adjustable austenitic transformation during operation, electroslag remelting and installation of optimal modes of heat-deformation treatment (annealing, forging, hardening and tempering). Manufacture of large parts such as wheels of extruders from forged steel brand 4Х4Н5М4Ф2with experimental and industrial tests for hot deformation of copper at operating temperatures below the critical point A1. Methods of research. Metallographic analysis of experimental die steels 4Х4Н5М4Ф2 and Н13 (analog 4Х4Н5М4Ф2). Results. Experimental-industrial tests of 4Х4Н5М4Ф2 forged steel extruder wheels for hot deformation of M1 copper have shown increased stability compared to H13 steel used at one of the Chinese enterprises. Scientific novelty. In the process of partial recrystallization of alloyed structural forged steel 4Х4Н5М4Ф2 a spheroidized carbide component is formed, which leads to improved machining of the workpiece for the manufacture of parts such as extruder wheels. Practical value. The possibility of using steel (4Х4Н5М4Ф2) with adjustable austenitic transformation in operation for a wide range of operating temperatures (below the critical point A1 and above the critical point A3) for hot deformation of copper (up to 630 °C), copper-nickel (900–950 °C) and aluminum alloy (450–500 °C) with increased service life was shown. To facilitate machining by cutting the workpiece in the manufacture of dies from steel 4Х4Н5М4Ф2, it was proposed to conduct a partial recrystallization, namely incomplete annealing at a temperature of 750±20 °C. The studied forged steel 4Х4Н5М4Ф2 is characterized with increased in hardness and strength limit compared to H13 steel, after operation of the wheels of extruders (manufacture of more than 60 tons of copper products).