Treatment Process for Bars

a technology of rolled bars and treatment process, which is applied in the direction of quenching devices, furnace types, furnaces, etc., can solve the problems of reducing mechanical resistance and impact resistance, affecting the quality of rolled bars, so as to achieve high quality, free of scoring and surface defects, and high quality
US20090044884A1Inactive Publication Date: 2009-02-19DANIELI & C OFF MEC SPA
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Patent Information

Authority / Receiving Office
US · United States
Patent Type
Applications(United States)
Current Assignee / Owner
DANIELI & C OFF MEC SPA
Publication Date
2009-02-19
Estimated Expiration
Not applicable · inactive patent

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Abstract

Treatment process for stainless steel bars, in particular a solution quenching, to be performed directly in-line downstream of the rolling mill which makes it possible to obtain a material devoid of intergranular corrosion and with microstructural characteristics suitable for subsequent uses. Advantageously, said process also makes it possible to improve the productivity of the entire rolling plant. The treatment is suitable to be performed on austenitic, ferritic, or austeno-ferritic stainless steel bars, Al—Cu alloy bars, Nickel alloy bars, and all other alloys requiring rapid cooling in order to prevent undesired phase precipitations. Prevention of intergranular corrosion obtained with the treatment process of the invention makes it possible to prevent problems, and relative costs, during surface treatment of the bars and those that could occur in final use.
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Description

FIELD OF THE INVENTION

[0001] The present invention relates to an in-line treatment process of rolled bars, in particular to a solution quenching treatment, at the outlet of the rolling train, of bars in stainless steel, nickel alloys or other alloys that require rapid cooling after rolling.STATE OF THE ART

[0002] The structure of austenitic steels is practically composed only of austenite stable at ambient temperature; the chromium carbides, which may be held in supersaturated solid solution in the austenite, are capable of precipitating, at the austenite grain boundary, when the steel is heated in the interval ranging from 450 to 850° C. or cooled slowly through this interval. The considerable carbide-forming power of the Cr causes disproportionation of the alloy at the grain boundary, while in the centre of the grains the Cr content remains practically unchanged. In the case in which the content of free Cr, that is, not bonded to form carbides, drops locally below the limit of stainl...

Claims

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