ESTIMATION OF TRIBOLOGICAL PROPERTIES OF LOW AND MEDIUM-CARBON STEELS AFTER HEAT TREATMENT AND SEVERE PLASTIC DEFORMATION
Eng Semenov, L Sh, Shuster, Assoc Prof, J Huang, Stud, Lin, R Rajendran
unpublished
The results of joint comparative tribological studies performed on structural steels with a carbon content of 0.2% and 0.45% are presented in this work. Three states were studied: the source (hot-rolled), after heat treatment (martempering) and after martempering with subsequent severe plastic deformation (SPD) by equal channel angular pressing (ECAP). It is established that the materials after different types of treatment are in different structure states, and show various shear strength of
more »
... esive bonds and adhesive (molecular) components of the friction coefficient in contact with tool steel. And the greatest effect hardening via grain structure refinement is observed on low-carbon steel. Medium-carbon steel has approximately the same tribological properties after heat treatment (martempering) and after SPD by an ECAP method. KEY WORDS: Introduction The technologies of metallic materials hardening by methods of severe plastic deformation (SPD) are gaining ground at the present time. One of the most effective methods is equal channel angular pressing (ECAP) [1, 2] and its development-ECAP-Conform [3], which has considerable potential for the industrial production of long-length products in the form of bars. It is known that more solid materials provide less wear and friction coefficient [4]. There are ways to increase the hardness in alloys in most cases through various types of heat treatment [5, 6]. The technology providing efficient and multiple increase of strength has been developed by the present moment. The technology is based on the methods of SPD and allows getting high-strength bulk metal materials [7]. One of the SPD methods is ECAP [3], which is carried out in several cycles of deformation. The essence of this method of increasing the material strength is maximum grinding of the grain structure to ultrafine-grained and nano-sizes [1, 8, 9]. The SPD methods enable significantly expanding the application fields of various metal materials due to effective increase of strength. The previous complex tribological studies of steel with a carbon content of 0.2% showed [10, 11], that the material treated by the SPD technology, namely the ECAP method demonstrated a lower friction coefficient and high wear resistance of the contact pair with tool steel. However, it is of great scientific and practical interest to justify practicability of conducting SPD as one of the competitive methods of increasing the strength of materials that are subsequently to be exploited in friction units.
fatcat:wwsyq5iov5bpndqfjmdj77vddm