IDENTIFICATION OF FACTORS CAUSING NITRIDATION OF CRUDE STEEL IN BOF BEFORE TAPPING

Branislav Buľko,Jaroslav Demeter,Jozef Kijac,Peter Demeter

doi:10.12776/ams.v20i1.206

Abstract

Determination of factors and measuring their impact on the amount of nitrogen in the metal is key attribute when optimizing technological and operational measures tending to minimize, respectively prevent of the final steel nitridization. Knowing the rate of influence of individual factors on the nitrogen content in the metal is crucial in dealing with prediction of the quantity for the production and processing stages of steel production in a closed production cycle. In this paper, factors determining nitrogen content in crude steel before tapping, using Cohen´s distribution table and graphical expression are presented. Influence of after-blows on nitrogen content is well known, but there are other factors which affect steel nitridization before tapping from oxygen converter.

Highlights

Nitrogen in steel causes brittleness of ferritic steels
2 Experimental conditions and materials Nitrogen content in crude steel was investigated in basic oxygen furnace before tap
The results of the nitrogen content in the metal were synchronized with the databases that contain information about the chemical composition of the metal, metal temperature, metal weights and other parameters, which were held on the stage of the manufacturing process, based on heat number and marking the point of taking samples

Summary

Introduction

Nitrogen in steel causes brittleness of ferritic steels. Dissolution of nitrogen as well as other diatomic gases in the liquid steel can be described by equation (1): N [ ] (1)while its content may be defined by Sieverts law (2):%[N ] kN (PN2 ) 2 (2)The content of dissolved nitrogen depends on the root of the partial pressure [1]. The nitrogen content in the final steel depends largely on the type of process [6]. The main goal of this paper is to analyse the various factors affecting the nitrogen content of crude steel produced by LD process.

Objectives

Results

Conclusion