Kawasaki Steel Corporation

Masaaki Kohno

Susumu Satoh

Kunio Fukuda

Takumi Ujiro

Kazuhide Ishii

Atsushi Miyazaki

Kazuhiro Seto

Chiaki Kato

Koji Yamato

Makoto Isobe

Shinji Yamazaki

Masahiro Yoshioka

Hiroshi Yaginuma

The invention provides hot-rolled steel strips which, after having been acid-pickled, can be directly used. The strips have no Cr-decreasing layer and no shot blasted marks on their surface and have good corrosion resistance. The invention also provides a technique of efficiently producing the hot-rolled steel strips. A steel slab having a Cr content of from 6.0 to 25.0 wt. % is hot-rolled, then coiled at a temperature not higher than 700&deg; C., then optionally quenched in water immediately after the coiling, then annealing in a reducing atmosphere, and thereafter acid-pickled in a solution of nitric acid/hydrochloric acid.

Method for producing chromium-containing hot rolled steel strip

Method of making a hot-rolled steel sheet having superior surface appearance, free of surface patterns and uneven glossiness from an austenitic stainless steel slab containing about 0.03 percent by weight or more of Cu, about 0.03 percent by weight or more of V, and about 0.01 percent by weight or more of Mo under any of the following conditions: (A) pickling in a nitric-hydrofluoric acid solution containing about 20 to 100 g/l of nitric acid and about 100 to 300 g/l of hydrofluoric acid; (B) controlling nitric-hydrofluoric acid content in response to the iron ion content in the solution; (C) a preliminary pickling step prior to finishing pickling; (D) grinding about 2 .mu.m or more of the surface after preliminary pickling and prior to finishing pickling; (E) causing counterflow with a relative flow rate of 0.5 to 5.0 m/sec on the sheet surface during finishing pickling; (F) adding sulfuric acid or sulfurous acid as a hydrogen ion source to the nitric-hydrofluoric acid solution; and (G) electrolysing during finishing pickling such that the ratio of the cathodic electrolysis time to the anodic electrolysis time is about 3 or more.

Method of making austenitic stainless steel sheet

Plated steel sheet

A hot-rolled stainless steel strip contains at least 10 wt % Cr and 1.0 wt % or less of Si, and has a controlled scale thickness of not more than 2.5 .mu.m in the surface layer. The average thickness of the Si-containing oxide layer formed in the scale/alloy substitute interface is 0.1 .mu.m or less. The hot-rolled stainless steel strip is produced by hot rolling at an elongation rate of at least 150 or hot rough rolling to form a sheet bar, descaling by spraying superhigh pressure water to the surface of the sheet bar at an impact pressure (p) of 25 kgf/cm.sup.2 or more and a flow rate density of 0.002 l/cm.sup.2 or more, and then finish rolling so that the maximum reduction ratio per pass satisfies certain disclosed criteria.

Hot-rolled stainless steel strip and method for producing the same

A ferrite-type hot-rolled stainless steel sheet is composed of a selected class of elements in specified amounts. Even when cold rolling and its subsequent process steps are omitted, the hot-rolled steel sheet is sufficiently workable and excellent in surface roughening resistance and high-temperature fatigue properties after working. The steel sheet is easy to produce with a wide range of annealing temperatures.

Ferrite-type hot-rolled stainless steel sheet having excellent

Fe--Cr--Al alloy foil having high oxidation resistance for a substrate catalytic converter. The alloy foil contains about: C: 0.02 wt. % or less, N: 0.02 wt. % or less, Si: 1.0 wt. % or less, Mn: 1.0 wt. % or less, Cr: from 15 to 26 wt. %, Al: from 4.5 to 8.0 wt. %, Sm: from 0.05 to 0.30 wt. %, Zr: from 0.01 to 0.10 wt. %, and Hf: 0.005 wt. % to 0.10 wt. %, the balance consisting of Fe and incidental impurities.

FE-CR-AL alloy foil having high oxidation resistance for a substrate of

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Chiba, Japan

Masaaki Kohno