The study aimed to examine the effect of the hydrostatic extrusion (HE) process on the machinability of Ti grade 2 (Ti) in the turning process. After the deformation with true strain ɛ = 2.28, the microstructure was significantly refined to a grain size of 100 nm, resulting in an increase in the mechanical properties, UTS strength by 190%, YS yield strength by 230%Cutting forces for Ti in the initial state and after HE were analyzed at cutting depths ap = 0.3 mm and 0.5 mm, the variables were cutting speed Vc (20, 30 and 50 m/min) and feed rate f (0.08 and 0.13 m/s).The impact of the microstructure refinement in Ti after HE on the high cutting depth machinability deterioration (ap = 0.7 mm) was identified. This phenomenon is particularly noticeable at lower cutting speeds Vc = 20 and 30 m/min at which cutting forces are higher. Application tests of Ti after HE showed a significantly lower susceptibility to buckling during threading. As a result of the tests carried out for the Ti in the initial state, it was not possible to achieve the tolerance of pitch diameter of the thread required by standards, d2 at two of the three cutting depths tested. In turn, for the Ti after HE, the thread tolerances required by the standards were achieved for all tested cutting depths.

In this investigation, three different explosive materials have been used to improve the properties of titanium grade 2: ammonal, emulsion explosives, and plastic-bonded explosives. In order to establish the influence of explosive hardening on the properties of the treated alloys, tests were conducted, including microhardness testing, microstructure analysis, and tensile and corrosion tests. It has been found that it is possible to achieve a 40% increase in tensile strength using a plastic explosive (PBX) as an explosive material. On the other hand, the impact of the shock wave slightly decreased the corrosion resistance of titanium grade 2. The change in corrosion rate is less than 0.1µm/year, which does not significantly affect the overall corrosion resistance of the material. The reduction in corrosion resistance is probably due to the surface geometry changes as a result of explosive treatment.

The study aimed to examine the effect of severe plastic deformation (SPD) using the hydrostatic extrusion (HE) method on the machinability of grade 2 titanium in the turning process. An analysis of the deformation process was carried out involving a two-stage process of cold hydrostatic extrusion with cumulative true strain ɛ = 2.28. After the deformation, the Ti grade 2 microstructure was strongly defected and significantly refined, resulting in a clear increase in the mechanical properties, UTS strength by 190%, YS yield strength by 230%, and hardness by 50%. The average grain size was 100 nm. Ti grade 2 in the initial state and after HE hydrostatic extrusion process was subjected to machining by turning analysis. Component cutting forces were analyzed at cutting depths a p = 0.3 mm and 0.5 mm, the variables were cutting speed V c and feed rate f . The cutting speeds for the materials in the initial state and after the HE process were 20, 30, and 50 m/min, and the feed rates were 0.08 and 0.13 m/s. Application tests of screws made of Ti grade 2 after HE were also carried out. The tests included the analysis of the surface roughness and the verification of the dimensional tolerance of the pitch diameter d2 required by standards for commercial screws.