Evaluation of Sulfide Inclusions before and after Deformation of Steel by Using the Electrolytic Extraction Method

Abstract

The characteristics of elongated MnS have a critical effect on fatigue anisotropy and all mechanical anisotropies. A comparative investigation of nonmetallic inclusions in both stainless steels and tool steels has been carried out in this study. The inclusion characteristics were investigated using electrolytic extraction (EE) followed by scanning electron microscopy combined with energy-dispersive spectroscopy (SEM-EDS). Overall, three types of MnS inclusions (type I (regular), type II (irregular) and type III (Rod)) were found in tool steels in as-cast samples, which had not been heat-treated. Furthermore, three types of MnS inclusions (Rod-like sulfide (RS), Plate-like sulfide (PS) and Oxysulfide (OS)) were found in samples taken after rolling. Based on the breakability of the elongated MnS, three types of inclusions, Type UU, UB and BB, where U represents the undamaged or unbroken edge of an inclusion and B represents the fragment or broken edge of an inclusion, were studied in both stainless steels and tool steels both before and after additional heat treatment. The effect of heat treatment and dissolving the metal layer during the EE process is also discussed. The results show that both processes have a limited effect on the breakability of inclusions in steels with carbon contents <0.42 mass%.

Using dynamic materials modelling approach to establish critical parameters for hot coiling of spring steels

“…Additionally, long time exposure under service conditions can cause evolution of non-metallic inclusion like MnS, which can adversely affect the properties, and performance of these grades of steel. Deformation-induced MnS can also be obtained during processing and this has been reported to have adverse effects on the properties of different steel grades [17,18]. To this end, it has become imperative to understand the critical deformation conditions that could lead to metallurgical flaws in this 55Cr3 spring steel.…”

Classification of Sulfides in High‐Sulfur Steel and Establishment of Automatic Sulfide Classification Method

“…It is very important to analyze each type of sulfide for better control of sulfides. [ 26,27 ] In the current study, sulfides in the high‐sulfur steel are manually divided into three types: chain‐like sulfides, cluster‐like sulfides, and individual sulfides according to their distribution. By summarizing the features of each sulfide type, an automatic sulfide classification method is proposed to distinguish different kinds of sulfides based on the normal statistical results, therefore, each sulfide type can be counted separately, providing a reliable data for evaluating whether the distribution of sulfides is in good condition or not, and giving a guideline for the improvement of sulfide control methods.…”