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:
May. 04, 1993
Filed:
May. 18, 1992
Atsushi Watanabe, Tokyo, JP;
Teruyuki Hasegawa, Tokyo, JP;
Tadashi Inoue, Tokyo, JP;
Tomoyoshi Okita, Tokyo, JP;
Yoshiteru Kikuchi, Tokyo, JP;
Hidetoshi Matsuno, Tokyo, JP;
NKK Corporation, Tokyo, JP;
Abstract
A method for manufacturing an Fe-Ni alloy cold-rolled sheet excellent in cleanliness and etching pierceability, comprising: preparing an Fe-Ni molten alloy, containing 30 to 45 wt. % nickel, and subjected to dephosphorization and decarburization; adding aluminum and flux to the Fe-Ni molten alloy in a ladle made of an MgO-CaO refractory containing 20 to 45 wt. %; strongly stirring the Fe-Ni molten alloy which contains the added aluminum and flux in the ladle to produce a CaO-Al.sub.2 O.sub.3 -MgO slag so as to react the Fe-Ni molten alloy with the CaO-Al.sub.2 O.sub.3 -MgO slag to deoxidize the Fe-Ni molten alloy while controlling a value of activity of SiO.sub.2 from 0.001 to 0.005 and a value of activity of Al.sub.2 O.sub.3 from 0.1 to 0.3 in the CaO-Al.sub.2 O.sub.3 -MgO slag, and the CaO-Al.sub.2 O.sub.3 -MgO slag having the following chemical composition: CaO and Al.sub.2 O.sub.3 : at least 57 wt. %, wherein the ratio of CaO/(CaO+Al.sub.2 O.sub.3) being at least 0.45, MgO: up to 25 wt. %, SiO.sub.2 : up to 15 wt. %, and oxides of metals having an oxygen affinity lower than that of silicon: up to 3 wt. % in total; casting the deoxidized Fe-Ni molten alloy into an ingot; and blooming, hot-rolling and cold-rolling the ingot to manufacture an Fe-Ni alloy cold-rolled sheet containing non-metallic inclusions comprising a composition in a region of a melting point of at least 1,600.degree. C., which region is defined by a liquidus curve of 1,600.degree. C. in a CaO-Al.sub.2 O.sub.3 -MgO ternary phase diagram and having a particle size up to 6 .mu.m in a total amount of up to 0.002 wt. % as converted into oxygen.