# US 8,465,806 B2 · Method for hot dip galvanizing of AHSS or UHSS strip material, and such material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,465,806 B2 - Document ID: US8465806B2 - Status: Granted - Kind: B2 - Application number: 12/598,366 - Filed: 2008-04-29 - Published: 2010-07-15 - Granted: 2013-06-18 - Earliest claimed: 2007-05-02 - Assignees: Tata Steel Ijmuiden B.V. - Applicants: Hendrik Bart Van Veldhuizen; Petrus Gerardus Commadeur - Inventors: Hendrik Bart Van Veldhuizen; Petrus Gerardus Commadeur - Web page: https://patentgrep.com/patent/US8465806B2 ## CPC - C21D 9/52: for wires; for strips {; for rods of unlimited length} - C21D 9/56: Continuous furnaces for strip or wire - C22C 38/02: containing silicon - C22C 38/04: containing manganese - C22C 38/06: containing aluminium - C23C 2/02: Pretreatment of the material to be coated, e.g. for coating on selected surface areas (C23C2/30 takes precedence) - C23C 2/0222: {in a reactive atmosphere, e.g. oxidising or reducing atmosphere (C23C2/024 takes precedence)} - C23C 2/0224: {Two or more thermal pretreatments} - C23C 2/024: {by cleaning or etching} - C23C 2/06: Zinc or cadmium or alloys based thereon - Y10T 428/12799: Next to Fe-base component [e.g., galvanized] - 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) - C22C: ALLOYS (treatment of alloys C21D, C22F) - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method for hot dip galvanizing of advanced high strength or ultra high strength steel strip material, such as dual phase steel, transformation induced plasticity steel, transformation induced plasticity assisted dual phase steel and twinning induced plasticity steel strip material. The strip material is pickled and thereafter heated to a temperature below the continuous annealing temperature before the strip material is hot dip galvanized. ## Claims ### Claim 1 Method for hot dip galvanizing of dual phase steel, transformation induced plasticity steel, transformation induced plasticity assisted dual phase steel or twinning induced plasticity steel strip material comprising, pickling the strip material and thereafter heating the pickled strip material to a temperature below a continuous annealing temperature of the strip material, between 400 and 600° C., before the strip material is hot dip galvanized; wherein Fe in the strip material is reduced during or after the heating to a temperature below the continuous annealing temperature and before the hot dip galvanizing; hot dip galvanizing the strip material after said heating, wherein the reduction is performed using H2N2 in the reducing atmosphere. ### Claim 2 (depends on 1) Method according to claim 1, wherein an excess amount of O2 is provided in the atmosphere during or after the heating of the strip material and before the reduction of the strip material. ### Claim 3 (depends on 2) Method according to claim 2, wherein the excess amount of O2 is provided in an amount of 0.05-5% O2. ### Claim 4 (depends on 1) Method according to claim 1, wherein the steel strip material is hot rolled before galvanizing to form a hot rolled strip material and the steel strip material is hot dip galvanized as the hot roiled strip material. ### Claim 5 (depends on 4) Method according to claim 4, wherein the hot rolled strip material is hot dip galvanized without a continuous annealing step between the hot rolling and the hot dip galvanizing of the strip material. ### Claim 6 (depends on 1) Method according to claim 1, wherein the steel strip material is cold rolled before galvanizing and hot dip galvanized as a cold rolled product, which has been annealed after cold roiling and before pickling. ### Claim 7 (depends on 6) Method according to claim 6, wherein the steel strip material has been pickled before the cold rolling. ### Claim 8 (depends on 1) Method according to claim 1, wherein the cold rolled strip material is produced from a hot rolled strip material or a belt cast strip material. ### Claim 9 (depends on 1) Method according to claim 1, wherein the steel strip material comprises 0.04-0.30% C, 1.0-3.5% Mn, 0-1.0% Si, 0-2.0% Al and 0-1.0% Cr, the remainder being Fe and inevitable impurities. ### Claim 10 (depends on 9) Method according to claim 9, wherein the steel strip material is a transformation induced plasticity steel strip material, comprising 0.15-0.30% C, 1.5-3.5% Mn, 0.2-0.8% Si and 0.5-2.0% Al, the remainder being Fe and inevitable impurities. ### Claim 11 (depends on 9) Method according to claim 9, wherein the steel strip material is a transformation induced plasticity steel strip material, comprising 0.15-0.24% C, 1.5-2.0% Mn, 0.2-0.6% Si and 0.5-1.5% Al, the remainder being Fe and inevitable impurities. ### Claim 12 (depends on 1) Method according to claim 1, wherein the steel strip material is a twinning induced plasticity steel strip material comprising between 10 and 40% manganese, and up to 10 aluminium. ### Claim 13 (depends on 1) Method according to claim 1, wherein the steel strip material is a twinning induced plasticity steel strip material comprising between 12 and 25% manganese, and up to 10% aluminium. ### Claim 14 Method for hot dip galvanizing of dual phase steel, transformation induced plasticity steel, transformation induced plasticity assisted dual phase steel or twinning induced plasticity steel strip material comprising, pickling the strip material and thereafter heating the pickled strip material to a temperature below a continuous annealing temperature of the strip material, between 400 and 600° C., before the strip material is hot dip galvanized; wherein Fe in the strip material is reduced during or after the heating to a temperature below the continuous annealing temperature and before the hot dip galvanizing; hot dip galvanizing the strip material after said heating, wherein the reduction is performed using 5-30% H2N2 in the reducing atmosphere. ### Claim 15 (depends on 14) Method according to claim 14, wherein an excess amount of O2 is provided in the atmosphere during or after the heating of the strip material and before the reduction of the strip material. ### Claim 16 (depends on 15) Method according to claim 15, wherein the excess amount of O2 is provided in an amount of 0.05-5% O2. ### Claim 17 (depends on 14) Method according to claim 14, wherein the steel strip material is cold rolled before galvanizing and hot dip galvanized as a cold rolled product, which has been annealed after cold rolling and before pickling. ### Claim 18 (depends on 14) Method according to claim 14, wherein the steel strip material comprises 0.04-0.30% C, 1.0-3.5% Mn, 0-1.0% Si, 0-2.0% Al and 0-1.0% Cr, the remainder being Fe and inevitable impurities. ### Claim 19 (depends on 14) Method according to claim 14, wherein the steel strip material is a twinning induced plasticity steel strip material comprising between 10 and 40% manganese, and up to 10 aluminium. ### Claim 20 (depends on 14) Method according to claim 14, wherein the steel strip material is a transformation induced plasticity steel strip material, comprising 0.15-0.30% C, 1.5-3.5% Mn, 0.2-0.8% Si and 0.5-2.0% Al, the remainder being Fe and inevitable impurities.