# US 4,394,188 A · Process for producing ferrite stainless steel sheets having excellent workability

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- Number: US 4,394,188 A
- Document ID: US4394188A
- Status: Granted
- Kind: A
- Application number: 06/290,713
- Filed: 1981-08-06
- Granted: 1983-07-19
- Earliest claimed: 1980-08-09
- Assignees: Nippon Steel Corporation
- Inventors: Jirou Harase; Tadashi Nakayama
- Web page: https://patentgrep.com/patent/US4394188A

## CPC

- C21D 8/04: to produce plates or strips for drawing, e.g. for deep-drawing
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)

## Abstract

Process for producing a ferrite stainless steel having excellent workability, comprising hot rolling a ferrite stainless steel slab with a total reduction of at least 80% in a temperature range of from 1150.degree. C. to 900.degree. C. at the central portion of the slab thickness, and, without annealing the hot rolled sheet, cold rolling the hot rolled sheet by a single step into a final thickness.

## Claims

### Claim 1

A process for producing a SUS 430 type ferrite stainless steel sheet having excellent workability, comprising hot rolling a ferrite stainless steel slab containing 0.03 to 0.1% C, 0.08 to 0.5% sol. Al and not less than 70 ppm N with a total reduction of at least 80% in the temperature range from 1150.degree. to 900.degree. C. at the central portion of the slab thickness, reduction by at least one pass of the hot rolling being not less than 35%, coiling at a temperature not lower than 800.degree. C. and, without subjecting the hot rolled steel sheet to annealing, cold rolling the hot rolled steel sheet by a single step into a final thickness.

### Claim 2 (depends on 1)

Process according to claim 1, in which the hot rolled steel sheet under as-hot-rolled condition contains AlN in an amount not less than 30 ppm of N as AlN.

### Claim 3 (depends on 1)

A process according to claim 1 wherein the ferrite stainless steel slab contains 70 to 220 ppm N.