The Effect of a Gear Oil on Abrasion, Scuffing, and Pitting of the DLC-Coated 18CrNiMo7-6 Steel

Remigiusz Michalczewski,Marian Szczerek,Andrzej Wieczorek,Marek Kalbarczyk,Anita Mańkowska-Snopczyńska,Edyta Osuch-Słomka,Andrzej Snarski-Adamski,Jan Wulczyński,Witold Piekoszewski,Waldemar Tuszyński

doi:10.3390/coatings9010002

Remigiusz Michalczewski, Marian Szczerek + Show 8 more

Open Access

https://doi.org/10.3390/coatings9010002

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Abstract

The transmissions of mining conveyors are exposed to very harsh conditions. These are primarily related to the contamination of the gear oil with hard particles coming from coal and lignite, which can cause intensive abrasive wear, scuffing, and even pitting, limiting the life of gears. One of the ways to prevent this problem is the deposition of a wear-resistant coating onto gear teeth. However, a proper choice of gear oil is an important issue. The abrasion, scuffing, and pitting tests were performed using simple, model specimens. A pin and vee block tester was employed for research on abrasion and scuffing. To test pitting, a modified four-ball pitting tester was used, where the top ball was replaced with a cone. The test pins, vee blocks, and cones were made of 18CrNiMo7-6 case-hardened steel. A new W-DLC/CrN coating was tested. It was deposited on the vee blocks and cones. For lubrication, three commercial industrial gear oils were used: A mineral oil, and two synthetic ones with polyalphaolefin (PAO) or polyalkylene glycol (PAG) bases. The results show that, to minimize the tendency forabrasion, scuffing, and pitting, the (W-DLC/CrN)-8CrNiMo7-6 tribosystems should be lubricated by the PAO gear oil.

Highlights

Gears are very often exposed to very harsh conditions
This paper presents an effect of fully formulated oils, intended for the lubrication gears made of 18CrNiMo7-6 steel
Uncoated vee block lubricated with the mineral oil; (b) (W‐DLC/CrN)‐coated vee block lubricated with thewith mineral (c) (W‐DLC/CrN)‐coated vee block vee lubricated with the PAO

Summary

Introduction

Gears are very often exposed to very harsh conditions. This concerns gears used in the transmissions of chain and belt conveyors working in coal and open pit mines. The harsh conditions are primarily related to the contamination of the gear oil with hard particles coming from coal and lignite. This can cause intensive abrasive wear, scuffing, and even pitting, limiting the life of gears. One can find information on successful applications of various coatings to reduce the tendency of gears to scuffing [2,3,4,5], micropitting [6], and to possibly reduce friction [7,8].

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