The Use of Coatings to Obtain the Diffusion Layer on the Walls of Molds

Gerasimova Alla

doi:10.11648/j.ijmsa.20160501.11

Abstract

In this work diffusion layers on narrow walls of crystallizers removed from service were created by aluminium spraying on M1 copper and МН2, 5КоКрХ copper alloy with subsequent heat treatment for increasing of life time of crystallizers in continuous casting machines. Layer thickness and microhardness have been assumed as basic measure of serviceability. To clarify the reasons of reducing the thickness of the diffusion layer on the copper alloy МН2, 5КоКрХ were conducted metallographic and microengineering research. The coating was applied on the wall alloy МН2, 5КоКрХ, the diffusion layer microhardness was measured on microthermometry PMT-3. The analysis found that increasing the thickness of the deposited coating and the temperature rise of the heat treatment, as a rule, lead to an increase in the thickness of the diffusion layer; change the security environment with 95%N2+5%H2 100%H2 does not change the thickness of the diffusion layer; a diffusion layer microhardness of 2-6 times higher than the microhardness of copper and is 1140-3880 MPa against 460-590 MPa on copper base. It is reasonable to spray aluminium thermal coating on narrow crystallizer walls with subsequent heat treatment in protective atmosphere using adjusted modes and proofing of a crystallizer in a continuous casting machine for estimation of wall state during exploitation and change of cast metal quality.

Highlights

Numerous parts of metallurgical equipment are made from copper and copper alloys which have high electro- and thermal conductivity [1]
The coating was applied on the wall alloy МН2, 5КоКрХ, the diffusion layer microhardness was measured on microthermometry PMT−3
The study is aimed to improve the quality of the cast metal by applying thermal coatings on the working surface of the mold of continuous casting of steel billets

Summary

Introduction

Numerous parts of metallurgical equipment (crystallizers, converter and blast furnace lances etc.) are made from copper and copper alloys which have high electro- and thermal conductivity [1]. At present gas-thermal spraying with subsequent heat treatment is used for obtaining of diffusion layers on metallurgical machinery elements [7]. Standard equipment for such coating spraying is relatively compact and low-price, dimensions of parts under treatment are not limited by anything, and it is possible to form local and double-side coatings [8, 9]. A result of thermal spraying of coatings on copper and copper alloys with subsequent heat treatment is diffusion layer with heat- and wear resistance necessary for improvement of Gerasimova Alla and Radyuk Aleksandr Germanovich: The Use of Coatings to Obtain the Diffusion Layer on the Walls of Molds metallurgical facilities life cycle [11]. Purpose of the study: The aim is to improve the quality of the cast metal by applying thermal coatings on the working surface of the mold of continuous casting of steel billets

Methods and Materials

Findings

Conclusions