Composite “1.2361 tool steel - Ti - TiO2” structure and its production by resistance welding with subsequent induction heat treatment

The composite “1.2361 tool steel - Ti - TiO2” structure was prepared by resistance welding (RW) with subsequent induction heat treatment (IHT). RW of tool steel with titanium was performed at an electric power in the range of 3.5-4 kW with the pulse duration of 0.25-1.0 s. IHT was performed at the temperatures in the range of 950-1600 °C for 5-60 s for titanium inserts, and the temperature of the steel substrate did not exceed the melting point (about 1370 °C). At the electric power of 3.5 kW with the pulse duration not more than 0.5 s, Fe-Ti transition area of the weld joint with the moderate hardness about 4.0 ± 0.5 GPa (410 ± 50 HV1) was formed. According to the results of scanning electron microscopy with energy dispersive X-ray analysis (EDX) and Vickers hardness test, titania coatings with high hardness about 2500 ± 250 HV1 and 950 ± 50 HV5 were formed on titanium surface after IHT at 1500 ± 50 °C for 30 ± 10 s. Preliminary results on the cuttability tests of the experimental replaceable cutting inserts were obtained, according to which the composite “1.2361 tool steel - Ti - TiO2” structure enabled the fine turning of X40Cr13 steel (43 HRC or 415 HV).