Control of MnS Inclusions in High- and Low-Sulfur Steel by Tellurium Treatment.

Feng Wang,Hao Guo,Jingshe Li,Wei Liu,Shuo Zhang,Shufeng Yang

doi:10.3390/ma12071034

Abstract

Manganese sulfide (MnS) inclusion in steel is related to the machinability of steel. Controlling the type and shape of MnS inclusion has been a problem for the steelmaking process for a long time. The effect of tellurium (Te) treatment on the control of MnS inclusion is studied with experiments and discussion of sequential solidification. The result shows that Te addition to the high- and low-sulfur steel dominantly changes the size and shape of MnS inclusions in steel. The aspect ratio of inclusions in cast steel changes with Te/S ranges from 0 to 1.9, which offers an effective way to control the MnS type and thus to improve the machinability and mechanical properties of steel. With an excessive Te addition, no further improvement could be observed by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS).

Highlights

Machinability is an important criterion in materials design for many applications.Free-cutting property is essential for some kinds of steel, which require lots of machining processes like gear steel and free-cutting steel [1,2,3]
The inappropriate type of Manganese sulfide (MnS) will lead to the decline of mechanical property
Type I, which is in a sphere shape, is said to be better for the mechanical property compared to the long, deformable type II and III MnS [5,6,7]

Summary

Introduction

Free-cutting property is essential for some kinds of steel, which require lots of machining processes like gear steel and free-cutting steel [1,2,3]. The inappropriate type of MnS will lead to the decline of mechanical property. According to Sims and Dahle [4], there are three types of MnS inclusions in cast steel. Type I, which is in a sphere shape, is said to be better for the mechanical property compared to the long, deformable type II and III MnS [5,6,7]. The problem of controlling MnS type in steel is raised to balance the free-cutting and mechanical property, which is hard to realize because it is not easy to precisely control the small content of Mn and S in steel

Methods

Results

Conclusion