The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 31, 1990
Filed:
Jun. 07, 1989
Tohei Ototani, Tokyo, JP;
Metal Research Corporation, Tokyo, JP;
Abstract
The disclosed method is a method of manufacturing clean steel comprising refining molten steel by adding additives of from not more than 0.5% to more than 0.001% by weight of molten steel to the molten steel bath, in vacuo or a non-oxidizing atmosphere within a melting furnace or vessel made of or lined with a basic refractory material consisting essentially of 7-90 wt % of CaO and 90-7 wt % of MgO, which total content being 70% to 99.9%, and optionally included a basic refractory material consisting of 30-0.1 wt % of at least one element selected from the group consisting of Al.sub.2 O.sub.3, CrO, ZrO.sub.2.SiO.sub.2, ZrO.sub.2, ZrC and C as selected components, and obtaining clean steel containing less than 30 ppm of oxygen, less than 30 ppm of sulfur, less than 150 ppm of nitrogen, 5 to 0.1 ppm of Mg and 25 to 0.1 ppm of Ca. Said additives comprises Al and at least one optional element selected from Ti, Nb, Ta, B and alkali earth metal. 5% of a solvent can be included to said additives.