# US 5,759,307 A · Method of producing a cold-rolled strip in one pass > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,759,307 A - Document ID: US5759307A - Status: Granted - Kind: A - Application number: 08/708,084 - Filed: 1996-08-30 - Granted: 1998-06-02 - Earliest claimed: 1995-09-01 - Assignees: Keramchemie GmbH; BWG Bergwerk- und Walzwerk-Maschinenbau GmbH - Inventors: Heinz Berger; Rolf Noe; Frank Barhold; Jorg Neumann; Andreas Noe; Ralf Waldmann; Bodo Block - Web page: https://patentgrep.com/patent/US5759307A ## CPC - B21B 45/06: of strip material (B21B45/08 takes precedence) - C23G 1/00: Cleaning or pickling metallic material with solutions or molten salts (with organic solvents C23G5/02) - C23G 1/08: Iron or steel - C23G 1/081: {solutions containing H2SO4} - C23G 1/085: {solutions containing HNO3} - C23G 1/086: {solutions containing HF} - C23G 1/106: {refractory metals} - C23G 3/02: for cleaning wires, strips, filaments continuously - B21B 1/28: by cold-rolling {, e.g. Steckel cold mill} - B21B 3/00: Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences {; Rolling of aluminium, copper, zinc or other non-ferrous metals}(altering special metallurgical properties of alloys, other than structure consolidation or mechanical properties resulting therefrom C21D, C22F) - B21B 3/02: Rolling special iron alloys {, e.g. stainless steel} - B21B: ROLLING OF METAL (auxiliary operations used in connection with metal-working operations covered in B21, see B21C; bending by rolling B21D; manufacture of particular objects, e.g. screws, wheels, rings, barrels, balls, by rolling B21H; pressure welding by means of a rolling mill B23K20/04) - C23G: CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS ## Abstract A method of producing a cold-rolled strip from a stainless, ferretic or austenitic high-grade steel or a titanium alloy, wherein the strip which has been wound into a coil and has been manufactured by a hot-rolling or casting process is subjected in one pass to the steps of unwinding the coil, mechanically descaling the strip if required, subsequently chemically and/or electrochemically first or black pickling of the strip, then cold-rolling the strip to finished dimensions, degreasing the strip as required, annealing the strip, finish-pickling the strip and, if necessary, passivating, dressing and stretcher-leveling the strip. The pickling step is carried out in a pickling solution which contains hydrochloric acid, sulfuric acid and/or nitric acid. ## Claims ### Claim 1 In a method of producing a cold-rolled strip of a stainless austenitic high-grade steel or a titanium alloy, the method including carrying out in one pass the steps of unwinding a coil produced by a hot-rolling or casting procedure and wound into a coil, subsequently subjecting the strip to a chemical and/or electrochemical first pickling step, and then cold-rolling the strip to finished dimensions, and annealing and finish-pickling the strip, the improvement comprising carrying out the first pickling step with a pickling solution containing at least one of hydrochloric acid, sulfuric acid and hydrofluoric acid. ### Claim 2 (depends on 1) The method according to claim 1, comprising carrying out the first pickling step and the finish-pickling step in separate pickling containers with different pickling solutions. ### Claim 3 (depends on 1) The method according to claim 1, comprising carrying out the first pickling step in at least one pickling container with a pickling solution mixture. ### Claim 4 (depends on 1) The method according to claim 1, comprising carrying out the first pickling step with a hydrochloric acid-containing pickling solution which contains at most 25% free hydrochloric acid and has a temperature of approximately 50.degree.-90.degree. C. ### Claim 5 (depends on 4) The method according to claim 4, wherein the hydrochloric acid-containing solution contains 10-17% free hydrochloric acid and has a temperature of 75.degree.-85.degree. C. ### Claim 6 (depends on 1) The method according to claim 1, carrying out the first pickling step with a sulfuric acid-containing pickling solution containing at most 45% free sulfuric acid and having a temperature of between 70.degree. C. and slightly below the boiling point of sulfuric acid. ### Claim 7 (depends on 6) The method according to claim 6, wherein the sulfuric acid-containing pickling solution contains 20-30% free sulfuric acid and has a temperature of 95.degree.-105.degree. C. ### Claim 8 (depends on 6) The method according to claim 6, comprising carrying out the first pickling step so as to produce a dark coating on the surface of the strip. ### Claim 9 (depends on 1) The method according to claim 1, comprising carrying out the first pickling step with a nitric acid-containing pickling solution containing at most 30% free nitric acid and having a temperature of approximately 30.degree.-90.degree. C. ### Claim 10 (depends on 9) The method according to claim 9, comprising carrying out the first pickling step so as to produce a layer of residual scale on the surface of the strip. ### Claim 11 (depends on 1) The method according to claim 1, comprising carrying out the first pickling step with a pickling solution containing less than 0.75% free hydrofluoric acid. ### Claim 12 (depends on 1) The method according to claim 1, comprising supplying at least the pickling solution containing hydrochloric acid to the strip with at least one spraying process. ### Claim 13 (depends on 12) The method according to claim 12, comprising guiding the strip through an immersion pickling bath between two successive spraying processes. ### Claim 14 (depends on 1) The method according to claim 1, comprising carrying out the first pickling step electrochemically with a current density of up to 50 A/dm.sup.2. ### Claim 15 (depends on 14) The method according to claim 14, wherein the current density is 10-20 A/dm.sup.2. ### Claim 16 (depends on 1) The method according to claim 1, comprising mechanically descaling the strip prior to the first pickling step. ### Claim 17 (depends on 1) The method according to claim 1, comprising degreasing the strip after cold-rolling the strip. ### Claim 18 (depends on 1) The method according to claim 1, comprising passivating, dressing and stretcher-leveling the strip after the finish-pickling step.