International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This study investigated the effect of cold plastic deformation at Bridgman anvil chamber temperature on the hardness and wear resistance of X160CrMoV12 steel using hardness testing, X-ray diffraction (XRD), abrasive grinding wear (AEMW) testing, optical examination, and scanning electron microscopy (SEM). Three batches of samples were prepared for the experiment: I – hardened, II – hardened and then tempered at 600°C for 1.5 hours, III – hardened and then plastically deformed. The samples were hardened at three temperatures: 1100, 1150, and 1200 °C. The highest amount of retained austenite, reaching 69.02%, was observed when hardening at 1200°C, while at lower temperatures, 17.36% and 38.14% were formed, respectively. After hardening (batch II), the amount of retained austenite decreased proportionally by approximately 7 times for each hardening temperature. The effect of plastic deformation (batch III) is observed by analysing the hardness of samples from the surface to the depth, reaching an average hardening depth of 0.08 mm. To check how well it holds up to wear, the surfaces of three test batches were tested using an abrasive grinding test with a load of 5N. Hardened and plastically deformed specimens showed greater resistance to abrasion than hardened and tempered specimens. The results confirmed that the optimal hardening temperature for achieving maximum wear resistance of this steel is 1100°C.

This study examines how thermal and mechanical effects influence hardness distribution in 4, 6, and 8 mm AA5754 aluminum plates welded using TIG with AC and DC currents. Vickers hardness (HV0.01) was measured alongside tensile tests to evaluate weld performance. Results show that AC welding produces higher but more variable hardness, while DC welding yields more stable profiles. Notably, thinner plates (4 mm) showed minimal hardness differences between current types due to faster cooling. Strain hardening increased hardness up to 125 HV and reduced variation. The extent of hardness stabilization and heat-affected zone size depended on plate thickness. Although current type influenced hardness distribution, it had little effect on fracture toughness.