## 1 Impact of Magnetic-Pulse and Chemical-Thermal Treatment on Alloyed Steels' Surface Layer
Each hardening processing method based on the deformation effect on the cutting tool has the following characteristics: mechanics of deformation, specific features of formation of geometrical and physical-mechanical properties of the surface layer, and the process conditions. Work hardening methods are divided into either static and dynamic ones. Static methods (e.g., rolling and pressing) are characterized by the stationarity of the deformation force and the impact and continuity of contact between the deforming element and the cutting tool. Dynamic methods (e.g., blasting, vibration, ultrasonic treatment, and embossing) are characterized by the deforming elements' intermittent contact and impulsive effect on the cutting tool's surface [10]. Additionally, widespread ways for combining static and dynamic loads are applied. All methods of magnetic treatment of tools and machine parts are classified as follows [6]: the processing of static magnetic field (intensity 100-1000 kA/m for exposure 10-300 s); magnetic-pulse processing field (intensity 50-2000 kA/m at a pulse duration of 0.1-10 s). The first method includes the following stages: processing demagnetization during 8-24 h; processing a single pulse with a directional (local) concentration of the magnetic flux on the workpiece; dynamic processing when the item is in a field of constant tension and rotates with a rotational speed of 1-50 s\({}^{-1}\) during 1-5 min; treatment with the free movement of the workpiece in the inductor's cavity. The magnetic-pulse treatment method includes the following stages: treatment without subsequent demagnetization; polycyclic processing (2-10 cycles) with exposure between cycles 1-20 min; processing using ferromagnetic cores; the local magnetic field concentrators; and machining in metal containers or chambers using ferrofluid. Almost all of these methods need the subsequent exposure of the workpiece on non-metallic substrates during 5-24 h.  
Tools made of carbon steel need high-speed processing by 1-2 cycles under the pulse duration of 0.3-1.5 s and exposure after treatment of approximately 8-12 h. Increasing the tool's mass increases the optimum pulse time 2-3 times. Tools made of hard alloys and composite materials need processing by 5-10 cycles under intensity of up to 4000 kA/m in the container with ferromagnetic fluid. In this case, exposure between treatment cycles depends on the tool's mass, geometry, and dimensions, which varied in a range of 0.5-5 min [10]. The most promising direction to increase the resistance of cutting tools from ferromagnetic materials is the processing of magnetic-pulse treatment. This treatment allows us to increase tool life due to changes in the mechanical properties of materials. This effect is achieved due to the complex magnetostrictive structural changes. For the surface hardening of tools and machine parts, the following procedures can be applied: thermal impact [11], laser hardening [12], electron-beam processing [13], cryogenic processing [14], flame quenching [15], and the quenching of high-frequency currents [16]. Among the various methods, surface alloying is the most applicable in producing tools from alloy steels after thermochemical treatment [17]. The chemical-heat treatment of cutting tools includes the diffusion saturation technology applied to the surface layer for elements C, N, B. In this case, cementation, nitriding [18], nitrocbarurizing [19], and boriding [20] were used. Notably, the choice of a proper chemical-thermal treatment method depends on the tool surface layer requirements and heat resistance of the tool's material. In ion implantation in the surface layer of the irradiated material, radiation defects occur [21]. These effects lead to changes in the material's properties (e.g., microhardness, toughness, ductility, thermal conductivity, and electrical resistance). However, ion implantation is not widely used in tool production due to the high cost and relatively low performance.