SAHYADRI International Journal of Research 56 |Vol 2| Issue 2 |Dec 2016| Study of E ect of Heat Treatment Processes On Material Properties of Manganese Steels G. Sandesh Kumar Rai 1 , Vishwanatha Nayak 2 , Ravindra Mallya 1 , J. Rohith Acharya 1 , P. Rajesh Rai 3 1 Mechanical Engineering Dept., Canara Engineering College, Bantwal, Mangalore-574219 2 Mangalore Marine College and Technology Kuppepadavu Post, Mangalore, Karnataka 574144 3 AJ Institute of Engineering and Technology, Bangrakuloor, Kodikal, Mangalore, Karnataka 575013 Email:sandeshkumarrai@gmail.com Abstract Heat treatment on manganese steel improves ductility, toughness, hardness and tensile strength and to relieve internal stress developed in the material. The hardness test, impact test, wear test, compression test and microstructure analysis were conducted on heat treated manganese steel, which has extensive uses in all industries including electronic, research and development elds. The manganese steel properties can be varied with the various heat treatment processes such as annealing, tempering, normalising, hardening and spheroidising. The material is given a micro nish for performing the microstructure analysis. The micro nish of the heat- treated specimen was super- nished in the single disc polishing machine. The polished specimens were etched for nding the exact microstructure. The optical microstructure images were taken at di erent magni cations and were studied. The test results show that tempering can be done to increase the toughness, annealing can be done to increase the toughness and ductility, normalising can be done to improve the hardness with some ductility and spheroidising to increase the machinability. Keywords:-annealing, charpy test, hardening, normalizing, spheroidising and tempering. 1 Introduction Steel has many practical applications in every aspect of life. The manganese steel is very important material for the industries working on metals including electronics. Manganese is hard and very brittle, di cult to fuse, but easy to oxidize. Manganese steel having manganese content of 1-1.5% makes the steel strong and tough and manganese content from 2-5% makes the steel hard and brittle. When manganese is from 11-14%, steel becomes very hard, tough, and nonmagnetic and possesses considerably high tensile strength. Manganese steel shows high percentage of elongation. It can be forged easily but di cult to be machined. Speci c gravity of manganese steel is 7.2, melting point 1343 ◦ C. Compositions of manganese steel are: Carbon 1.2-1.6%, Manganese 11- 14%, Chromium 1.5-2.5% and Silicon 0.5%. The manganese content in carbon steels is often increased for the purpose of increasing hardening and improving strength and toughness. Manganese is a silvery-gray metal resembling iron. Manganese is present in all steels as a de-oxidizer. When manganese is absent or very low, the predominant sulphide is iron sulphide (FeS), which forms the eutectic with iron, has a nity to form thin continuous lms around the primary crystals during solidi cation of the steel. A higher content of manganese in the presence of carbon substantially increases the wear resistance. The process of heat treatment is carried out rst by heating the metal and then cooling it in water, air, oil and brine water. The purpose of heat treatment is to soften the metal, to change the grain size, to modify the structure of the material and relieve the stress in the material. The various heat treatment processes are annealing, normalizing, hardening, tempering and spheroidising. Heat Treatment is the controlled heating and cooling of metals to alter their physical and mechanical properties without changing the product shape. The most important heat treatments and their purposes are: a) Normalizing - it will improve strength along with some ductility; b) Surface hardening - Produces a local wear resistant hard surface by induction, ame, or laser; c) Hardening and tempering - it will increase hardness and gives improved strength and higher proof stress ratio; d) Stress relieving - to reduce or relieve Internal stresses remained after casting and a low-temperature heat treatment; e) Austempering - it will yield to give bainitic structures of high strength along with signi cant ductility and good wear resistance; f) Annealing - It will improve ductility and toughness and reduce hardness. L.A. Dobrzanski et al [1] have investigated high- manganese austenitic steels with Nb and Ti microadditions in variable conditions of hot-working, which showed microstructure evolution in various conditions of plastic deformation. Microstructure of steel was subjected to solution heat treatment at temperature of 900 ◦ C and obtained ne-grained microstructure of austenite phase. In their subsequent work [2] they have determined the force-energetic parameters of hot-working in hot- compression tests carried out in a temperature range