Study on the Bonding Mechanism of Copper-Low Carbon Steel for Casting Compounding Process

Huirong Li,Haichao Zhang,Tao Ma,Yungang Li,Yueying He

doi:10.3390/met11111818

Abstract

The casting compounding process for copper-steel composite material has broad prospects of application, but due to the lack of supporting theories (especially the bonding mechanism of copper-steel at high temperatures), it is developing slowly. In this research, copper-steel composite materials for different casting temperatures have been prepared by the casting compound process. The results show that, for the casting compound process, the stable copper-steel transition layer can be formed in a short time, and the bonding of copper and low carbon steel is the result of both the diffusion of Cu in low carbon steel and the dissolution of Fe in molten copper. The diffusion coefficient of Cu in the low carbon steel is mainly concentrated in the range of 4.0 × 10−15–8.0 × 10−14 m2/s. However, for casting compound process of copper-steel, as the temperature rises the thickness of the copper-steel transition layer gradually decreases, while the Fe content in the copper layer gradually increases. At the same time, the analysis of the glow discharge results shows that, during the solid-liquid composite process of copper-steel, the element C in steel has a great influence. As the temperature rises, the segregation of C intensifies seriously; the peak of the C content moves toward the copper side and its value is gradually increases. The segregation of C would reduce the melting point of the steel and cause irregular fluctuations of the diffusion of Cu in low carbon steel. Therefore, a relatively lower molten copper temperature is more conducive to the preparation of copper-steel composite materials.

Highlights

Copper is the earliest metal used by mankind
When the temperature rises from 1100 ◦C to 1200 ◦C, the thickness of the transition layer decreases from 82.1 μm to 70.0 μm; the Fe content in the copper layer increases gradually as the temperature rises
When the temperature rises from 1100 ◦C to 1200 ◦C, the Fe content in the molten copper increases from 1.84% to 3.14%

Summary

Introduction

Copper is the earliest metal used by mankind. Due to its excellent electrical conductivity, thermal conductivity, and corrosion resistance [1], copper is widely used in electrical appliances such as motors and transformers. Cui Wenfang et al, found that the enrichment of Fe in Cu-Fe alloy could be effectively achieved through rolling and aging diffusion [23] and, at the same time, Dawei Yuan et al, found that adding Mg to the Cu-Fe alloy could effectively promote the enrichment and precipitation of Fe [24], thereby reducing the effect of higher Fe content in copper on the conductivity of Cu-Fe alloy. For the copper-steel composite metals, the corresponding metallographic analysis, scanning electron microscope analysis, and glow discharge detection were carried out to analyze the diffusion behavior of the elements involved in the casting compound process. The results will be the theoretical basis for the casting compound process of copper and steel

Experimental

Analysis on the Dissolution Behavior of Fe in Molten Copper

The Influence of Other Elements on the Formation of Transition Layer

Findings

Conclusions