Kawasaki Steel Corporation

Dai Nippon Toryo Co., Ltd.

Furukawa Aluminum Co., Ltd.

Koji Yamato

Shigeru Umino

Hajime Kimura

Yasushi Kato

Akira Yasuda

Susumu Satoh

Takumi Ujiro

Toshio Ichida

Koichi Hashiguchi

Kenji Takao

Makoto Isobe

Hideo Ogishi

Susumu Sato

Atsushi Miyazaki

Kazuo Mochizuki

Mitsuyuki Fujisawa

Nobuo Totsuka

Hajime Ogata

Ichiro Tanokuchi

Motohiro Nabae

Masaaki Kohno

Yasuji Uesugi

Rinsei Ikeda

Masaki Mabuchi

Naoki Nishiyama

Toshitake Hanazawa

Manabu Ohori

Kenichiro Akao

Toshihiro Kikuchi

Hideo Koumura

Kouichi Hashiguchi

Junji Kawabe

Chromium steel sheets having an excellent press formability

It is directed to provide an Fe--Cr alloy exhibiting an excellent ridging resistance and surface characteristic, comprising:

Fe-Cr alloy exhibiting excellent ridging resistance and surface

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

A method of recovering and reproducing a tinning liquid containing Fe ions and other detrimental cations by the steps of removing cations from the tinning liquid by passing the tinning liquid or a diluted liquid of the tinning liquid through a strong-acid cation exchange resin to obtain a recovered acid, thereafter reproducing the strong-acid cation exchange resin and desorbing adsorbed cations into a solution containing an acid by passing the acid through the exchange resin to which the cations have been adsorbed, precipitating and separating Sn ions in the form of a precipitate of an Sn compound from the solution into which the cations have been desorbed while maintaining Fe ions as ions in this solution, mixing and dissolving the precipitate of the Sn compound or a compound reduced from the same in the recovered acid to reproduce and reuse the mixture of the Sn compound and the recovered acid as a tinning liquid, and discharging the solution containing Fe ions out of the system of the tinning liquid.

Method for recovering and reproducing tinning liquid

In the preparation of a galvanized steel strip by continuously heating and anneal reducing a steel strip and subsequently admitting it, without contact with the ambient air, into a molten zinc bath to coat the strip with zinc, there is provided a method for preparing a galvanized or galvannealed steel strip having minimal uncoated defects, characterized in that a steel strip having a composition which contains

Method for preparing galvanized steel strip having minimal uncoated

A surface-treated aluminum material comprising an aluminum or aluminum alloy substrate, a chromate film deposited on the substrate, and an organic resin mixture film deposited on the chromate film is provided. The chromate film is deposited to a coating weight of from 5 to 100 mg/m.sup.2 calculated in terms of elementary chromium on the aluminum substrate. The organic resin mixture film is deposited to a dry film thickness of from 0.05 to 3.0 .mu.m, and comprises (a) 100 parts by weight of an organic resin, (b) 0.5 to 40 parts by weight of a powder lubricant having an average particle size of from 0.05 to 20 .mu.m, said average particle size being in the range of from 1.0 to 10 folds of the dry film thickness, and (c) 1.0 to 40 parts by weight of electroconductive finely divided particles having an average particle size in the range of from 0.05 to 5 .mu.m, said average particle size being in the range of from 1.0 to 2 folds of the dry film thickness. The organic surface-treated aluminum material has remarkable weldability, workability as well as corrosion resistance.

Surface-treated aluminum material having improved spot resistance

The improved corrosion-resistant steel plate with an organic coating comprises a steel plate having a zinc or zinc alloy plate layer which is overlaid with a chromate film which in turn is coated with an organic resin paint film. The organic resin coat comprises an epoxy resin having a dialkanolamine incorporated into its bisphenol A skeleton, an amino resin, and silica. The dialkanolamine combines with the amino resin to provide satisfactory curability at low temperatures; at the same time, it combines with the silica to provide a satisfactory film reinforcing effect. The organic coat formed of this composition can be effectively cured at low temperatures and yet it will neither dissolve nor soften upon swelling under the action of the alkali that is generated during cationic electrodeposition at the interface between the electrodeposited film and the organic coat. Thus, the organic coat has good paint adhesion, high corrosion resistance, as well as good workability and weldability and makes the steel plate suitable for use as an automotive part after painting. If the proportion of trivalent chromium in the chromate film and the amounts of zinc oxide and silica sol to be incorporated as additives are properly adjusted, the organic coating will exhibit satisfactory resistance to chromium dissolution and hence its paint adhesion and corrosion resistance are further improved to make the steel plate more suitable for use as an automotive part after painting.

Steel plate with organic coating having improved corrosion resistance

The improved corrosion-resistant steel plate with an organic coating comprises a steel plate having a zinc or zinc alloy plate layer which is overlaid with a chromate film which in turn is coated with an organic resin paint film. The organic resin coat comprises an epoxy resin which is prepared by reacting with an isocyanate compound and has a dialkanolamine incorporated into its bisphenol A skeleton, and silica. The dialkanolamine combines with a urethane-modified epoxy resin to provide satisfactory curability at low temperatures; at the same time, it combines with the silica to provide a satisfactory film reinforcing effect. The organic coat formed of this composition can be effectively cured at low temperatures and yet it will neither dissolve nor soften upon swelling under the action of the alkali that is generated during cationic electrodeposition at the interface between the electrodeposited film and the organic coat. Thus, the organic coat has good paint adhesion, high corrosion resistance, as well as good workability and as-worked corrosion resistance and makes the steel plate suitable for us an automotovie part after painting.

Steel plate with organic coating having improved corrosion resistance in

A method of producing a hot-dip galvannealed steel sheet from a very-low-carbon cold-rolled steel sheet containing not less than 0.01 wt % but not more than 0.1 wt % of Ti, by subjecting the cold rolled steel sheet to a process conducted in a continuous hot-dip galvanizing system including a heat treatment, hot-dip galvanizing and a subsequent galvannealing. The method is characterized by the steps of: subjecting the cold-rolled steel sheet to a degreasing and an acid cleaning; subjecting the degreased and acid-cleaned steel sheet to a heat treatment conducted in a reducing gas atmosphere; and cooling the heat-treated steel sheet at a temperature not lower than 380.degree. C. but not higher than the hot-dip galvanizing bath temperature, before the steel sheet is subjected to the hot-dip galvanizing. The very-low-carbon cold- rolled steel sheet contains, besides not less than 0.01 wt % but not more than 0.1 wt % of Ti, not more than 0.005 wt % of C, not less than 0.01 wt % but not more than 0.1 wt % of Al, not less than 0.01 wt % but not more than 0.1 wt % of Ti, and the balance substantially incidental inclusions and Fe.

Method of producing hot-dip galvannealed steel sheet free of Ti

A continuous dip-plating apparatus for a steel strip has a pot containing a metal melt which forms a plating bath, a device for causing the steel strip to run through the plating bath such that the steel strip makes a turn around a sink roll in the plating bath so as to be pulled upwardly above the surface of the plating bath, and a wiping device disposed above the pot and adapted for adjusting the amount of deposition of the metal melt to the steel strip. The apparatus further has a pair of flow regulating plates for suppressing deposition of dross to the steel strip. The flow regulating plates are arranged in parallel with and in the vicinity of the portion of the steel strip running upwardly through the plating bath with the upper ends of the flow regulating plates being disposed substantially at the same level as the plating bath. Preferably, the height of the portion of each flow regulating plate below the level of the surface of the plating bath is not smaller than 50 mm, while the distance between each flow regulating plate and the steel strip is preferably not greater than 80 mm. It is also preferred that the upper end of each flow regulating plate is positioned between a level which is 10 mm below the surface of the plating bath and a level which is 50 mm above the surface of the plating bath.

Continuous dip-plating apparatus for steel strip

A galvannealed steel sheet having a superior spot weldability characteristic in which the steel sheet has a base steel sheet cold-rolled from a material containing 0.005 wt % or less of C, 0.005 to 0.05 wt % of Ti, 0.01 to 0.1 wt % of Al, 0.005 to 0.015 wt % of Nb and 0.0002 to 0.002 wt % of B. In the process for making, the hot-dip plating layer applied after the alloying heat treatment has an Fe content of from 9 wt % to 12 wt %.

Galvannealed steel sheet having improved spot-weldability

Composite plated steel strips comprising a zinc base layer electrodeposited on at least one surface of a steel strip exhibit excellent corrosion resistance with or without painting provided that the zinc base layer contains 0.1 to 10% by weight of cobalt, 0.05 to 5% by weight of chromium, 0.05 to 8% by weight of aluminum, and optionally, 0.05 to 5% by weight of Si, the balance being zinc. Such composite plated steel strips are prepared by subjecting a steel strip to composite electroplating in an acidic zinc plating bath which contains at least one water-soluble compound of Co.sup.2+ in an amount of 0.3 to 60 g/l of metallic cobalt, at least one water-soluble compound of Cr.sup.3+ in an amount of 0.2 to 2.5 g/l of metallic chromium, a pseudo-boehmite like alumina sol in an amount of 0.5 to 20 g/l of alumina, and optionally, colloidal silica in an amount of 0.5 to 20 g/l of silica at pH 1 or higher and a current density of at least 40 A/dm.sup.2.

Method for making high corrosion resistance composite plated steel strip

Composite plated steel strips comprising a zinc base layer electrodeposited on at least one surface of a steel strip exhibit excellent corrosion resistance with or without painting provided that the zinc base layer contains 0.1 to 10% by weight of cobalt, 0.05 to 5% by weight of chromium, 0.05 to 8% by weight of aluminum, and optionally, 0.05 to 5% by weight of Si, the balance being zinc. Such composite plated steel strips are prepared by subjecting a steel strip to composite electroplating in an acidic zinc plating bath which contains at least one water-soluble compound of Co.sup.2+ in an amount of 0.3 to 60 g/l of metallic cobalt, at least one water-soluble compound of Cr.sup.3+ in an amount of 0.2 to 2.5 g/l of metallic chromium, a pseudo-boehmite like alumina sol in an amount of 0.5 to 20 g/l of alumina, and optionally, colloidal silica in an amount of 0.5 to 20 g/l of silica of pH 1 or higher and a current density of at least 40 A/dm.sup.2.

High corrosion resistance composite plated steel strip

Growing community of inventors

Chiba, Japan

Koji Yamato