High Temperature Corrosive Environment in a Sintering Plant for Pig Iron Production and Its Effect on Different Steel Grades
The harsh environment in a sintering plant for pig iron production leads to high temperature corrosion of the sinter grates. In the present study, a detailed analysis of the corrosives in such applications is given to understand materials failure. Various steels are tested, revealing effects of various alloying concepts, the resulting phases and their corrosive behavior in this complex corrosive environment at ≈900 °C. In order to understand the underlying corrosion mechanisms, detailed analyses are performed. Results indicate mainly chlorine, sulfur, and oxidation based corrosive decay at elevated temperature and a high relevance of protecting alloying elements within the steels.
High temperature corrosion studies of cermet particle reinforced NiCrBSi hardfacings
Abstract Metal matrix composite hardfacings provide various types of heat and wear resistant products. They are widely used in high temperature aggressive environments due to their excellent high temperature corrosion and wear resistance. In this study, Cr3C2–Ni and TiC–NiMo particles were used to reinforce a NiCrBSi matrix in plasma transferred arc welding process. These cermet particle reinforced hardfacings were examined on their oxidation behaviour and high temperature corrosion in different solid salts to optimise the field of application under high temperature conditions. Corrosion behaviour in solid salts is strongly dependent on the corroding anion. Cr3C2–Ni reinforced hardfacings behave better in oxidative and sulphate/phosphate environment, while TiC–NiMo hardfacings show better resistance against chlorine and carbonate ions up to 700 °C. Additionally, oxidation is no critical exposure for these types of hardfacings.
Prophets praying for, or preying on people’s faith: A reflection on prophetic ministry in the South African context
In mainline churches, the ministry of prophecy or the prophetic ministry involves the proclamation of the gospel. This, in turn, is related to the every-believer ministry. However, there is now a resurgence of the prophetic ministry as a special office as evidenced by the establishment of neo-prophetic churches. This article argues that neo-prophetic churches are tapping into people’s longing for the fresh divine word to speak directly into their personal situations. The article also probes whether neo-prophets in the prophetic activities are not also preying on people’s faith.