Program                     

COURSE'S CONTENT:

There are 16 hours os training including theorical and practical aspects, trought classes, exercises and debates of cases of the participant companies.

Obs: The course will have simultaneous translation.

PROGRAM:

Course: OVERVIEW OF METALLURGICAL KNOW HOW IN THE MOLD OF CONTINUOUS CASTING FOR SLABS, SQUARES AND ROUNDS.

Presenters:           Dr. Klaus Schwerdtfeger – Technische Universität Clausthal
                                 Dr. Carlos Cicutti – SIDERAR  Argentina.  

First Day Morning:

 

Introduction – Professor Klaus Schwerdtfeger

Short overview over the area of continuous casting and the topics of the previous courses. Outline of present course.

General Characteristics of Solidification of Steels and of the Resulting Solidification Structure – Professor Klaus Schwerdtfeger

.   Formation of mushy zone during solidification of steels;

.   Peritectic solidification;

.   Macroscopic solidification structure;

.   Microscopic solidification structure: dendrites and microsegregation;

.   Primary grain size;

.   Mechanisms of development of macrosegregation;

.   Spot segregates.

                 

Heat transfer in the mold – Professor Carlos Cicutti

.   Overview. Mechanisms;

.   Measurements. Integral heat flux. Heat flux distribution;

.   Effect of process variables: Casting speed, Mold fluxes, Steel grade, Others;

.   Effect of mold heat transfer on defects. Literature results;

.   Mold thermal monitoring. Typical instrumentation. Breakout detection system;

            .   Practical examples of thermal monitoring in a slab casting machine: Paper ISS 2002.

First Day Afternoon:

 

Mold friction – Professor Carlos Cicutti

.   Overview. Lubrication in the mold. Mold powders and oil lubrication

.   Some background on mold oscillation should be included (definition of negative strip time and other parameters)

.   Liquid and solid friction. Basic equations

.   Plant data. Factors affecting mold friction. Transient events, Influence of steel composition, Effect of casting powders, Influence of oscillation parameters. Relationship with defects

.   Practical example of friction monitoring in a continuous casting machine of round bars: Paper AISTech 2005.

 

Performance of Casting Flux in the Mold – Professor Klaus Schwerdtfeger

       .   Structure and behavior of  the flux layer between strand and mold

       .   Consumption of casting powder

          >   Dependence of consumption on casting parameters and flux properties

          >   Optimum consumption

      .   Depth of liquid slag pool on meniscus

      .   Thickness of flux layer in the gap

      .   Rim Formation

      .   Slag/metal reactions at the meniscus

      .   Principles of Powder Selection

 

Casting Flux Exercises – Professor Klaus Schwerdtfeger

      Second Day Morning:

 
Characterization of mold fluxes – Professor Carlos Cicutti

.   Heat transfer across the slag layer;

.   Viscosity and breaking temperature. Equations;

.   Mold powder crystallization. Solidification behavior;

.   Methods used to characterize mold powders. Laboratory tests. Plant trials.

 

Fluid Flow in Mold and SEN  - Professor Klaus Schwerdtfeger

      .   Flow pattern in the steel melt in the mold

    >   Flow pattern in slab molds

    >   Some metallurgical effects of bulk flow pattern

      .   Non-uniformity of meniscus level

    >   Non-uniformity of meniscus level caused  by the bulk flow pattern

    >   Gravity waves

      .   Fundamentals

      .   Surface waves observed in the continuous casting mold

    >   Meniscus height oscillation induced by mold oscillation

    >   Ripples made by rising argon bubbles

    >   Slag entrainment

       .   Fluid flow in the SEN

    >   Pressure Distribution in SEN Assembly

    >   Argon Injection into the SEN

             .   Modification of Fluid Flow in the Mold by Electromagnetic Stirring and Electromagnetic Braking

Second Day Afternoon

 
Steel Castability – Professor Carlos Cicutti

>   Steel cleanliness. General discussion;

>   Deoxidation inclusions. Evolution along the process;

>   Calcium treatment. Influence of calcium on inclusion composition;

>   Castability window. The influence of sulfur content;

>   Steel reoxidation. Main sources. Associated problems.

>   Plant results. Nozzle deposits formation. Paper I&SM 2003.

 

Meniscus Level Control – Professor Klaus Schwerdtfeger

        .   Introduction

        .   Problems Caused by Meniscus Level Fluctuations

            >   Cracks

            >   Surface Defects other than Cracks

            > Shape Defects

.    Meniscus Level Control

           >   Sensors for Meniscus Level Measurements

           >   Features of Meniscus Level Fluctuations

           >   Closed Loop Control Circuit

     Closing Words