THE EFFECT OF MAGNETIC PULSE PROCESSING ON PHASE TRANSITIONSIN THE SURFACE LAYER OF A CUTTING AXIAL TOOL OF TOOL STEEL

Abstract

The effect of magnetic pulse processing of axial cutting tools made of tool steels Р6M5 (W ≈ 6 %; M_o ≈ 5%)
and Х6ВМФ (C_r ≈ 6 %; W ≈ 1 %; M_o ≈ 1 %; V ≈ 1 %) on their structure, phase composition and microhardness were
studied. An abnormally high content of residual austenite in the cutting edge of the drill made of steel Х6ВМФ was
found. It is shown that as a result of magnetic pulse processing of a drill made of steel Х6ВМФ, the amount of residual
austenite in the cutting edge decreased from V_γ = 78 % to V_γ = 62 %, and the microhardness of the surface increased from
550 to 830 HV 0.025. It is established that MPP of drills made of Р6M5 steel leads to a slight decrease for austenite in
the cutting edge of the drill and an increase in the microhardness of the edge from 660 to 750 HV 0.01. It is established
that the superposition of a magnetic field during the magnetic pulse processing of steels leads to a shift in the
temperature in the beginning of the martensitic transformation, which is accompanied by a decrease in the austenitic phase amount in the steels and an increase in their microhardness. In addition, the effect of magnetic field pressure on
the surface of the processed tool leads to deformation of the processed material, which can also be accompanied by the
effect of deformation-activated  γ->α transformation of steel hardening.

Fig. 2. Table 2. Ref.: 16 titles.