Sae 52100 Is A Commonly Used High Carbon Low Alloy Steel For Various Applications Like Bearings, Forming Rolls, Spindles, Tools And Precision Instrument Parts. Though This Steel Is Mostly Used In Hardened And Tempered Condition, Alternate Or Supplementary Strategies Of Surface Hardening May Be Useful In Applications Where Hardness And Wear Resistance And Not The Core Strength Is Of Primary Concern. For Understanding The Scope, Extent And Applicability Of Such Modification, It Is Logical To Carry Out The Surface Engineering Treatments On This Steel In Annealed Rather Than In Hardened Condition. In Bearing Application, It Is Now Suggested That Austempered (Bainitic) Structure Could Offer Greater Toughness And Fatigue Strength In This Steel Than That Possible With Hardened And Tempered Condition. Thus, Surface Hardening Of Sae 52100 Steel In The Present Study Has Been Carried Out Both In Annealed And Austempered Condition By Several Techniques To Improve The Surface Mechanical Properties Like Hardness And Wear Resistance. The Thesis Is Presented In Six Chapters. Chapter1 Presents Introduction To The Subject Matter And Chapter 2 Provides A Comprehensive Summary Of Properties Of Sae 52100 Steel, Surface Degradation And Surface Engineering Techniques Chapter 3 Summarizes The Current Trend Of Plasma Nitriding Technique And The Experimental Results Of Plasma Nitriding Of This Steel In Annealed Condition. Chapter 4 Summarizes The Experimental Results And Analysis Of Combination Of Conventional Electrodeposition Of Chromium Followed By Gas Nitriding On The