摘要:
An object of the present invention is to make it possible, without necessitating an alkali pretreatment, to form a zinc oxide layer having excellent sliding properties on a hot dip galvanized steel sheet not subjected to alloying after galvanizing and thus having a relatively low degree of surface activity. Another object of the present invention is to make it possible to manufacture a hot dip galvanized steel sheet having higher area ratio of Zn oxide layer formed on a coating surface and larger thickness of the Zn oxide layer. Specifically, the present invention provides a method for manufacturing a hot dip galvanized steel sheet comprising: subjecting a steel sheet to hot dip galvanizing and subsequent temper rolling; bringing the steel sheet into contact with acidic solution having pH buffering capacity; retaining the steel sheet for 1 second to 60 seconds after the contact with the acidic solution; and rinsing the steel sheet with water, to form a zinc oxide layer on a coating surface of the steel sheet, characterized in that the method further comprising:carrying out the temper rolling by either rolling the steel sheet first with a dull roll having Ra≧2.0 μm at rolling reduction rate ≦5% and then with a bright roll having Ra≦0.1 μm at rolling reduction rate ≦3% or rolling the steel sheet first with a bright roll having Ra≦0.1 μm at rolling reduction rate ≦3% and then with a dull roll having Ra≦2.0 μm at rolling reduction rate ≦5%.
摘要:
An object of the present invention is to make it possible, without necessitating an alkali pretreatment, to form a zinc oxide layer having excellent sliding properties on a hot dip galvanized steel sheet not subjected to alloying after galvanizing and thus having a relatively low degree of surface activity. Another object of the present invention is to make it possible to manufacture a hot dip galvanized steel sheet having higher area ratio of Zn oxide layer formed on a coating surface and larger thickness of the Zn oxide layer. Specifically, the present invention provides a method for manufacturing a hot dip galvanized steel sheet comprising: subjecting a steel sheet to hot dip galvanizing and subsequent temper rolling; bringing the steel sheet into contact with acidic solution having pH buffering capacity; retaining the steel sheet for 1 second to 60 seconds after the contact with the acidic solution; and rinsing the steel sheet with water, to form a zinc oxide layer on a coating surface of the steel sheet, characterized in that the method further comprising: carrying out the temper rolling by either rolling the steel sheet first with a dull roll having Ra≧2.0 μm at rolling reduction rate ≦5% and then with a bright roll having Ra≦0.1 μm at rolling reduction rate ≦3% or rolling the steel sheet first with a bright roll having Ra≦0.1 μm at rolling reduction rate ≦3% and then with a dull roll having Ra≦2.0 μm at rolling reduction rate ≦5%.
摘要:
A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2.ZnSO4.xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2.ZnSO4.3-5H2O.
摘要:
A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2·ZnSO4·xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2·ZnSO4·3-5H2O.
摘要:
A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2.ZnSO4.xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2.ZnSO4.3-5H2O.
摘要:
A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2.ZnSO4. xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2.ZnSO4.3-5H2O.
摘要:
A method for manufacturing a galvanized steel sheet, includes: galvanizing a steel sheet; bringing the surface of the steel sheet into contact with an aqueous solution containing zinc ion in the range of 5 to 100 g/l as the zinc ion concentration, having a pH of 4 to 6, and having a liquid temperature of 20 to 70° C., holding the steel sheet for 1 to 60 seconds; and then washing and drying the steel sheet. The solution containing zinc is preferably one containing zinc sulfate, for example. According to the method, a galvanized steel sheet having an oxide layer having an average thickness of 10 nm or more and mainly containing zinc formed on the surface of the steel sheet and having excellent press formability can be stably manufactured in a short time.
摘要:
A galvanized steel sheet has an organic inorganic complex coating on the surface thereof which contains an organic resin and a crystalline layered substance and has an average film thickness of 0.10 to 2.0 μm. The organic inorganic complex coating contains the crystalline layered substance in a solid content of not less than 0.5 parts by weight with respect to 100 parts by weight of the solid content of the organic resin.
摘要:
A method for producing a galvanized steel sheet includes contacting a steel sheet with a zinc-containing aqueous solution having a zinc ion concentration of 1 to 100 g/l, contacting the steel sheet with an aqueous solution with a pH of 6 to 14, washing the steel sheet with water, and then drying the steel sheet. An example of the zinc-containing aqueous solution is a solution containing zinc sulfate. According to the method, an oxide layer which has an average thickness of 10 nm or more and which principally contains zinc is formed on the steel sheet and the galvanized steel sheet can be stably produced at high speed in a reduced space so as to have excellent press formability.
摘要:
A method for treating plastics, which is feasible on plastics containing films mixed therein, which is capable of performing dehydrochlorination simultaneously, and which provides processed plastics capable of being easily size-reduced. The method includes mixing the plastics with an organic solvent at a temperature not lower than 150.degree. C.; allowing the plastics to dissolve and/or swell; removing the organic solvent or both the organic solvent and low-boiling point components from the treated solution thereafter; and solidifying the resulting product. The method can produce solid fuels and reducing agents for ores.