A study on the mechanism of desulphurisation and dephosphorisation of liquid steel by Na 2 CO 3 flux treatment

IOP Conf. Ser.: Mater. Sci. Eng.

2022

In modern times, selection criteria of materials are solely based on its utilization. The characteristics of materials like high temperature sustainability with regard to its strength and corrosion resistance is the primary requirement to satisfy its operations. Industries categorised in sectors like energy, manufacturing, electronics etc. greatly rely on input materials and their purity decides their performance. Amongst many developed alloys, nickel-based alloys find their position in applications having temperatures from cryo to nuclear ranges. One of such unique materials, being used from minute components of semiconductor industry to huge components of marine industry is UNS N06003. It is basically Ni-Cr based alloy having greater than three-fourth fraction of nickel. For major applications wrought material is widely used, but cast material marks their positions in selected applications. This paper deals with casting of UNS N06003 and improving its quality. The reasons associated with cast defects and drawbacks of defects in terms of performance have been discussed. To minimize casting defects and produce a sound casting, this research adopts a novel approach of removal of unwanted gaseous elements. In degassing stage, molten metal is introduced with the combination of calcium-based fluxes which mainly remove the entrapped gases and lighter impurities in the form of slag. It has been found that the addition of quicklime (CaO) in combination with calcium carbide (CaC2) resulted in reduction of gaseous elements like nitrogen, phosphorus and sulphur. Up to 33% reduction of gaseous elements has been detected.

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Section: Undesirable Presence Of Gasesmentioning

confidence: 99%

Study on Defect Reduction in Casting of Ni-Cr alloy (UNS N06003)

IOP Conf. Ser.: Mater. Sci. Eng.

2022

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“…Addition of solid degassing fluxes at appropriately high temperature is very commonly seen in the foundries and is comparatively cheaper method. The basic fluxes quicklime, limestone, fluorspar, calcium carbide, dolomite and sodium carbonate are used for removal of N, P and S from the alloys [38,39,40]. The addition of quicklime liberates CO2 in the form of the collector gas upon heating and has proven giving satisfactory results for nickelbased alloys.…”

Section: Degassingmentioning

confidence: 99%

A Brief Study on Defect Reduction of Cast Fe-Ni-Cr Alloy (UNS N08120) for Petrochemical Industry

Advances in Science and Technology

2022

In the current advancing world, operability and ease in processability of a material define its selection criteria for the intended applications. Hence, the industrial applications requiring high temperature sustenance, strength and corrosion resistance desperately demand the materials which employ simple processing in an economical way. Contemplating last few decades, it has been discovered that industries like petrochemical, power generation, nuclear energy, etc. greatly relied on nickel-based alloys till Fe-Ni-Cr based alloys were not introduced. The usable components are obtained either in cast or wrought form as per requirements. Fully killed alloy, developed under controlled conditions with some precautions during the casting process can lead to sound casting. The current study adopts a novel preliminary approach to control the quality of cast UNS N08120 material and minimize the possibility of defect generation. The possible reasons behind cast defects and how they transform into intrinsic defects have also been discussed. Calcium-based fluxes are introduced to molten metal as a degassing agent for the elimination of lighter impurities and entrapped gases. By the addition of quicklime (CaO) as a flux material during the sand casting process, an attempt has been made to reduce the presence of gases and impurities by more than 80%.

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Influence of Heat Treatment on Hardness and Microstructure of Cast Fe–Ni–Cr Alloy

Lecture Notes in Mechanical Engineering

2022