Nanostructured surfaces

Corrosion-mechanical properties of structural steels with surface nanostructure
Maksymiv O.V.1, Kyryliv V.I.1, Chaikovs’kyi B.P.2, Gurey V.I.3, Zvirko O.I.1
1 Karpenko Physico-Mechanical Institute of the NAS of Ukraine,
5, Naukova St., Lviv 79060, Ukraine.
E-mail: okyryliv@yahoo.com
2 Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies,
50, Pekarska St., Lviv 79010, Ukraine.
3 Lviv Polytechnic National University,
12, Bandery St., Lviv 79013, Ukraine.

The most widely used method of formation of nanocrystalline structures (NCS) is severe plastic deformation (SPD) which allows obtaining bulk and surface NCS. Mechanical-pulse treatment (MPT) is among them. It generates SPD by high-speed friction. Strengthened surface layer with NCS formed by MPT owns modified structural-phase state and chemical composition due to its alloying from special technological media (TM) which are supplied in the friction contact zone during MPT. MPT of structural low-alloy steels provides rising of surface hardness, strength, wear resistance, resistance to fatigue, corrosion fatigue and contact fatigue failure. NCS also prevents hydrogen penetration into the substrate being hydrogen permeation barriers [1]. The influence of different types of TM (mineral oil, tap water and air) during MPT on fatigue and corrosion fatigue of 45 steel and contact durability of 20ХН3А steel were studied in the paper.
The fatigue and corrosion fatigue in artificial sea water of 45 steel after MPT using air and mineral oil as TM were studied. It was indicated that MPT increased its fatigue strength in 1.3 times and corrosion-fatigue strength in 2.2 times compared with grinded specimens. It should be noted that type of TM during MPT didn’t influence significantly on fatigue strength limit, whereas air as TM provided corrosion-fatigue limit σ-1 = 160 MPa compared with mineral oil σ-1 = 140 MPa. The same regularity was observed during contact durability investigations of 20ХН3А steel in tap water and industrial oil. It was showed that contact durability of 20ХН3А steel specimens (cementation + quenching + tempering at 150 °C, HRC 59…60) after MPT in air is higher than after MPT in mineral oil or tap water.

1.	H. Nykyforchyn, V. Kyryliv, O. Maksymiv, O. Zvirko Mechanical fabrication methods of nanostructured surfaces. In: Handbook of modern coating technologies. Fabrication methods and functional properties. Amsterdam, Elsevie; 2021. p. 25-67.