This paper discusses the major sources of residual stress generation in the steel microstructure during cooling process of as-cast steel (slabs, blooms, and billets). The stress configuration of the steel microstructure changes during quenching due to stresses introduced to the microstructure by these sources. The influence of each source in increasing the stress distribution within the microstructure during quenching is explained via corresponding formula and qualitative discussion in separate sections. The stresses accumulated during cooling may introduce the residual stress concentration zones in the microstructure of the steel.
These stress concentration zones may result in flaws, microcracks or voids formation. Consequently, it may lower the soundness of the steel and cause deviation of the thermo-mechanical properties of the cast steel from the initially designed and customer desired specified properties.

The control of non-metallic inclusions is an important tool for steel properties optimization. Most related actions of this control involve the prevision of the slag-metal and inclusion-metal equilibrium, aiming at implementation of operational practices to obtain a more adequate inclusion profile.
Computational thermodynamics has proved to be a powerful tool in the prevision of equilibrium in different metallurgical systems, especially in the metal-oxide system in question. The aim of this work is to present the application of computational thermodynamics in the study of formation and control of non-metallic inclusions in steels, mainly during secondary refining. This work shows that the careful application of computational thermodynamics can drastically reduce the empirics in the process development for the control of non-metallic inclusions in steels, contributing to an increase in the efficiency of the process manufacture, to improve the present product quality and to enable the economic development of new products.

news in steel

Daehan Pyeongtaek modernizes existing VCC® mill with new SMS group billet welder and VCC® line to produce 5.0-ton coils

DaehanSteel Co. Ltd., South Korea, awarded SMS group an order to modernize its existing VCC® (Vertical Compact Coiler) of the rolling mill in its Pyeongtaek plant, which is located in the Seoul area.

New at wire 2020 in Düsseldorf: Special exhibition areas for Fasteners and Springs

wire 2018 exceeded all records attained so far and this success might still be topped: wire 2020 in Düsseldorf will open up for the first time with Fasteners and Springs forming independent exhibition areas under the roof of wire 2020. Start of registration for potential exhibitors is by end of January, 2019.

Well ventilated - Blast furnace blowers in South Korea modernized with Siemens technology

The international steel maker, Posco, is one of the world's largest steel producers. To ensure consistently high levels of steel production, the company has invested in modernizing the blowers on its blast furnaces at its main plant in Pohang using Siemens drive technology.

New additions to the SSAB Multisteel range

Pressure vessel and shipbuilding steels according to European and US standards now also included.