Overview of Materials Used for the Basic Elements of Hydraulic Actuators and Sealing Systems and Their Surfaces Modification Methods

Abstract

The article is an overview of various materials used in power hydraulics for basic hydraulic actuators components such as cylinders, cylinder caps, pistons, piston rods, glands, and sealing systems. The aim of this review is to systematize the state of the art in the field of materials and surface modification methods used in the production of actuators. The paper discusses the requirements for the elements of actuators and analyzes the existing literature in terms of appearing failures and damages. The most frequently applied materials used in power hydraulics are described, and various surface modifications of the discussed elements, which are aimed at improving the operating parameters of actuators, are presented. The most frequently used materials for actuators elements are iron alloys. However, due to rising ecological requirements, there is a tendency to looking for modern replacements to obtain the same or even better mechanical or tribological parameters. Sealing systems are manufactured mainly from thermoplastic or elastomeric polymers, which are characterized by low friction and ensure the best possible interaction of seals with the cooperating element. In the field of surface modification, among others, the issue of chromium plating of piston rods has been discussed, which, due, to the toxicity of hexavalent chromium, should be replaced by other methods of improving surface properties.

Investigation Tribological Behavior of Plasma Sprayed Ni-Based Coating Prepared on Aluminum Alloy Under Different Temperatures

“…Piston can be classified into cast iron piston, steel piston, aluminum alloy piston and combined piston, etc [3][4] . Among them, aluminum alloy piston is often used to make piston materials because of its small density and can greatly reduce the mass of the piston and reciprocating inertia force [5][6][7][8] . Aluminum alloy is widely used in construction engineering, mechanical equipment and other industries because of its light weight, low price and easy processing [9] .…”

Wear Resistance of Selected Anti-Wear Coatings Used in Multi-Material Composite Hydraulic Cylinders

“…Plastics are widely used in the design of machine components (Skowrońska et al, 2021). Their satisfactory mechanical properties, combined with good tribological properties, self-lubrication and the possibility of modifying the composition, allow them to be used in elements such as gears, pumps and others (Chihai et al, 2019;Krawczyk, 2021;Kujawa et al, 2019;Li et al, 2021;Majdič & Strmčnik, 2019;Zhang et al, 2021).…”

Experimental Research on Polymer-Based Coaxial Sealing Systems of Hydraulic Cylinders for Small Displacement Velocities

“…Hydraulic cylinder sealing system performance is influenced by numerous variables that cannot be simultaneously taken into consideration for obtaining generalized mathematical relationships. Speeds or properties of the sealing system components materials, roughness of the contacting surfaces, and temperature of the sealed fluid are only a few such quantities that affect the operational behavior of sealing systems [4][5][6]. The importance of an optimum sealing system design follows also from the conclusion of the study published by Oprean et al [7], which asserts that 44% of the operational malfunctioning of hydraulic cylinders is due to flawed sealing.…”