Nuclear Welding Report

Modeling of phase changes of hypo eutectoid steels

Dr. Suresh Akella, Mr. B Ramesh Kumar,

Sreyas Institute of Engineering & Technology, Nagole, Hyderabad 500068. Institute of Plasma Research, Bhat, Gandhinagar- 382428. [e-mail] Abstract: Austenitic steels have low carbon content and belong to the hypo eutectoid range such as SS304, SS304L, SS316. These steels are preferred material for nuclear welded structures. The computational modeling of the welding process is required to understand the distortion &residual stress. This work is about the phase changes and incorporating the alloy elements in the Iron – Iron carbide diagram.

1. INTRODUCTION

Austenitic Stainless Steels are the most used stainless Steels, with a normal

In 300 series for more corrosion resistance. 304 along with 304L series is the most used in the 300 series. In 316 type, 2% Cr replaces equivalent % of Mo for enhanced pitting corrosion. L, low carbon grades became popular with the advent of low cost melting process AOD, Argon Oxygen Decarburization. Austenitic steels are hypo eutectoid steels with carbon content less than eutectoid composition of 0.76%. The lever rule determines the percentage of

In this study the equations developed by earlier authors were first evaluated for different regions to obtain the temperature distribution and verify the consistency of progress of heating, up to liquidous temperature and cooling back to the ambient temperature. The process of heating and cooling is a variable that can change because of the welding process, tig, ebw, lASER etc., adopted which will determine the rate of heat inflow and thus the rate of temperature rise. Similarly, while cooling the process of cooling, normalizing, annealing, air water or water quenching will determine the formation of the type of steel. A slow annealing type cooling in a furnace will retain the Austenite, A faster cooling in oil or normalizing will help form Bainite. A faster cooling say by forced water can lead to Martensite