A large number of engineering components are damaged by surface phenomena such as wear, corrosion, erosion, thermal and mechanical fatigue. In the meantime, the equipment required in various factories and industrial processes suffers considerable damage from wear. A common way to extend the lifespan of tools that are used under strict working conditions and are highly susceptible to wear is to provide a hard coating on their surface. One of these methods is hardfacing. The hardfacing process is an effective way to reduce costs, maximize wear resistance, and extend the service life of machine parts by overcoming serve wear conditions. Research findings indicate that the addition of boron affects, not only the formation ofcarbides but also the hardness of the part as well as the wear resistance of the alloy and the hardness of the part increases with increasing boron. In this study, the effect of boron addition on Fe-Cr-C alloy as a coating on carbon steel was investigated by gas tungsten arc welding on an ST37 steel substrate. For this purpose, powders with different percentages of boron were prepared by mechanical alloying method. The paste was prepared from alloyed powder and after applying the paste on the steel surface and is drying. Then it was applied to the substrate using the gas tungsten arc welding method. The resulting microstructures were examined by scanning electron microscope and EDX analyses. The results showed that the addition of boron to the alloy caused the formation of carbide (M 3 C, M 7 C 3 , and M 23 C 6 ) and boride (M 3 B 2 , M 2 B and MB 2 ) phases in the austenitic matrix. The coated specimens were subjected to hardness and wear tests and it was found that the high volume fraction of carbides and borides increased the hardness up to 1200 HV for the samples containing 0.99 and 1.4% boron. It was also found that the sample containing 0.99% boron had the lowest wear rate. To determine the wear mechanism, wear surfaces were evaluated by scanning electron microscope and the results of the wear test showed that abrasive wear is the main wear mechanism. Keywords: Coating, Plain Carbon Steel, Boron Alloy, Gas Tungsten Arc Welding