Manufacture of High-C Welding Materials and Development of High-C Welding Techniques

Study on Rail Welding with High-C Welding Materials (Report 1)

Abstract

This paper describes the use of high-C welding materials for rail welding, which provide rail weld metal with improved wear resistance. The high-C weld metal prevents liquation cracking at rail HAZ caused by the significant difference in the melting points between weld metal and HAZ when using conventional low carbon low alloy electrodes.
Fundamental studies have been made on how to manufacture electrodes with carbon up to 1% and how to avoid solidification cracking likely to occur in high carbon weld metal.
The results of this study are as follows :
1) The high-C electrodes have been successfully manufactured
2) The microstructure of high-C weld metal is of fine lamellar pearlite which is known to be highly wear-resistant.
3) The liquation cracking at HAZ can be avoided by the use of weld metal with carbon higher than 0.4%.
4) The occurrence of weld metal solidification cracking is facilitated in high-C weld metal. This cracking can be prevented by a control of molten pool configuration through appropriate manipulation of electrodes.