PL196721B1 - Hot-dip zinc coating bath - Google Patents

Abstract

Hot-dip galvanizing bath containing 0.1 - 0.5% by weight of tin and lead, titanium, nickel, bismuth, the rest zinc and the inevitable impurities, characterized by the fact that it contains by weight: 0.1 - 0.3% lead, 0.01 - 0.1% nickel, 0.1 - 0.5% bismuth and 0 - 0.1% titanium,

Description

REPUBLIC

POLAND

(12) PATENT DESCRIPTION (19) PL (11) 196721 (13) B1 (21) Application number: 350866 ^{(51) Int.Cl.}

C23C 2/04 (2006.01) (22) Filed on: 26.11.2001

Patent Office of the Republic of Poland

(54) Hot dip galvanizing bath (73) The right holder of the patent: AGH University of Science and Technology Stanisława Staszica, Krakow, PL (43) Application was announced: 02.06.2003 BUP 11/03 (45) The grant of the patent was announced: 31.01.2008 WUP 01/08 (72) Inventor (s): Edward Guzik, Krakow, PL Dariusz Kopyciński, Krakow, PL Zbigniew Miodowski, Świnoujście, PL Mirosław Winiarski, Szczecin, PL (74) Representative: Postołek Elżbieta, AGH University of Science and Technology

⁽⁵⁷⁾ Hot-dip galvanizing bath containing 0.1-0.5% by mass of tin and lead, titanium, nickel, bismuth, the rest of zinc and unavoidable impurities, characterized by the fact that it contains: 0.1-0.3% by mass of lead, 0.01 - 0.1% nickel, 0.1 - 0.5% bismuth and 0 - 0.1% titanium,

PL 196 721 B1

Description of the invention

The subject of the invention is a hot-dip galvanizing bath for steel products with a high content of silicon and phosphorus and iron castings.

The chemical composition of steel has a significant impact on the thickness and quality of zinc coatings. For the evaluation of steel intended for hot-dip galvanizing, the equivalent of silicon and phosphorus is given, which is determined by the formula (Si + 2.5P) 1000%. When the content of silicon and phosphorus exceeds the critical level of 150%, a thick and brittle zinc coating with a dull gray appearance is produced.

There is known from the Polish patent specification No. 125 692 a method of producing protective coatings made of zinc alloy on steel pipes, containing by weight: 0.01 - 0.10% magnesium, 0.2 - 1.5% lead, 0.002 - 1.2% tin, 0.005 - 0.6% antimony, 0.002 - 0.06% cadmium, the rest is zinc, or from an alloy containing by weight: 0.005 - 0.05% magnesium, 0.2 - 1.5% lead, 0.002 - 1.2 % tin, 0.005 - 0.6% antimony, 0.002 - 0.06% cadmium, 0.005 - 0.05% titanium, the rest zinc.

Moreover, a bath for hot-dip galvanizing of steel products is known from Polish patent description No. 186 172, which contains by weight: 3 - 15% of tin, lead in concentrations up to saturation and 0 - 0.06% of at least one element of aluminum, calcium and magnesium, the rest zinc and unavoidable contamination.

Known from the book by P. Mass and P. Peissker entitled "Hot dip galvanizing", Agencja Wydawnicza Placet, Warsaw 1998. Technigalva technology consists in hot-dip galvanizing in a bath containing by weight: 0.08% nickel, <0.007% lead, <0.003% cadmium, <0.002% iron, <0.001% tin, <0.001% copper, the rest zinc. Known from the publication of Ph.Begnin, M.Bosschaerts, D.Dhaussy, R.Pankert, M.Gilles entitled "GALVECO" A solution for galvanizing reactive steel ", The Bulletin of the Bismuth Institute, 2000, No. 76, the bath contains in its composition by weight: 0.05% nickel, 1.8% tin and 0.5% bismuth.

The hot-dip galvanizing bath containing 0.1 - 0.5% by weight of tin and lead, titanium, nickel, bismuth, the rest of zinc and unavoidable impurities, is characterized by the fact that it contains by weight: 0.1 - 0.3% lead, 0, 01 - 0.1% Nickel 0.1 - 0.5% Bismuth and 0 - 0.1% Titanium.

The advantage of the bath according to the invention is that its chemical composition selected in such a way that, despite the high equivalent of silicon and phosphorus in the steel, amounting to over 150%, a tight coating of the same required thickness and shiny appearance is obtained, without the defects of the microstructure, which effectively protects steel products and iron castings against corrosion, especially of the marine environment. In addition, the obtained coating has a continuous alloy layer with diffusion adhesion to the substrate and is characterized by increased corrosion resistance at the grain boundaries.

P r z y k ł a d l

The previously prepared samples of St3S steel according to PN88-H-84020 with the silicon and phosphorus equivalent of 484.50% were immersed for 10 minutes into the alloy bath, containing by weight: 0.04% nickel, 0.3% lead, 0.4% bismuth, tin 0.5%, the rest zinc and the inevitable impurities. A protective coating with a thickness of 250 nm was obtained, which is characterized by good adhesion to the substrate and a glossy appearance.

P r z x l a d II

The previously prepared samples of DH36 steel according to PN93-H-92147 with the silicon and phosphorus equivalent of 222.25% were immersed for 10 minutes into the alloy bath with the composition as in example 1. A protective coating with a thickness of 195 μm was obtained, which is characterized by good adhesion to the substrate and with a glossy appearance.

P r x l a d III

The previously prepared steel samples as in Example 1 and II were immersed for 10 minutes into an alloy bath containing by weight: 0.04% nickel, 0.3% lead, 0.4% bismuth, 0.5% tin, 0.05% titanium , the rest is zinc and the inevitable pollution. Protective coatings with lower thicknesses, 180 μm and 120 μm, respectively, were obtained, which are characterized by good adhesion to the substrate, but with a worse appearance, due to the increased amount of ash that is formed during the hot-dip galvanizing process.

PL 196 721 B1

For comparison, the samples made of the same steel as in example 1 and 2 were hot-dip galvanized, which were immersed in the bath containing by weight: 0.04% nickel, the rest zinc and the inevitable impurities. After 10 minutes, protective coatings of much greater thickness were obtained, respectively; 700 μm and 500 μm, with inferior appearance and often defective.

Claims (1)

Patent claim Hot-dip galvanizing bath containing 0.1 - 0.5% by weight of tin and lead, titanium, nickel, bismuth, the rest of zinc and unavoidable impurities, characterized by the fact that it contains by weight: 0.1 - 0.3% lead, 0.01 - 0.1% nickel, 0.1 - 0.5% bismuth and 0 - 0.1% titanium,