[Kamboj*, 4.(6): June, 2015] ISSN: 2277-9655 (I2OR), Publication Impact Factor: 3.785 (ISRA), Journal Impact Factor: 2.114 http: // www.ijesrt.com © International Journal of Engineering Sciences & Research Technology [222] IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY OPTIMIZATION OF PROCESS PARAMETERS AND STUDY OF HARDNESS DURING HARD FACING OF MILD STEEL USING TAGUCHI METHOD Mr. Vikas Kamboj*, Er. Brij Bhushan, Dr. Abhishek Kamboj * M.tech research scholar A.P at H.E.C Jagadhri (Haryana) H.O.D at H.E.C Jagadhri (Haryana) ABSTRACT Hard facing is an important tool in tribology in which a layer of wear resistant material deposited over base metal or substrate to improve surface characteristics. There are numerous processes and consumables available in the market to improve the surface characteristics of components. This technique has potential to deposit hard-faced layer on substrate. The properties usually sought are greater resistance to wear from abrasion, impact, adhesion (metal-to- metal), heat, corrosion or any combination of these factors. Hard facing is applied only to specific areas of metal parts that are exposed to wear. There is often no need to protect the entire surface of a component from wear. Hard facing can be applied selectively and in different thickness to suit the exact requirements of a piece of equipment, thereby proving a most economical way of combating wear. Shielded metal arc welding is most commonly used process for hard facing due to its easy availability and versatility of operation. Low carbon steel is selected for the present work as substrate material due to its low cost, easy availability and variety of applications. In the present work a detailed study was done to study the effect of current, types of hard facing electrode and number of layers on substrate on micro-hardness and wear behavior of low carbon mild steel 1020 deposit by SMAW. KEYWORDS:. INTRODUCTION Welding plays an important role in the development of our society and mankind as a whole. One of the indexes used for measuring the prosperity of a country is the per capita steel consumption. Higher the production of steel, the greater is the role of welding. Welding is a process of permanent joining of two materials through localized coalescence resulting from a suitable combination of temperature, pressure and metallurgical conditions. Depending upon the combination of temperature and pressure from a high temperature with low pressure to a high pressure with low temperature, a wide range of welding processes has been developed [24]. While there are many methods for joining metals, welding is one of the most convenient and rapid methods available. It is a principal means of fabricating and repairing metal parts. The term welding refers to the process of joining metals by heating them to their melting temperature and causing the molten metal to flow together. Welding, like any skilled trade, is broad in scope and one cannot become a welder simply by reading a book. One need practice and experience as well as patience, however much can be gained through study. Historically the welding was developed in the ancient times and can be traced during the Bronze Age when the lap joints were made by heating and hammering the two metal pieces. During excavation, parts and tools have been found, which were welded by pressure welding during the time as back as 1000 B.C [26]. The earliest known form of welding, called forge welding, dates back to the year 2000 B.C. Forge welding is the process of joining metals by heating and hammering until the metals are fused (mixed) together. Although forge welding still exists, it is mainly limited to the blacksmith trade. Some of the most recently welding technologies include: Friction welding, which uses rotational speed and upset pressure to provide friction heat, the pressure