# US 2014/0290802 A1 · Surface treatment method and coating method for steel material, and method for producing machine component > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0290802 A1 - Document ID: US20140290802A1 - Status: Published application - Kind: A1 - Application number: 14/350,724 - Filed: 2012-09-12 - Published: 2014-10-02 - Earliest claimed: 2011-10-25 - Assignees: Komatsu Ltd.; Nippon Kazai Co., Ltd.; Cotec Corporation - Inventors: Haruji Morita; Tsuneo Tate; Akira Shiozawa - Web page: https://patentgrep.com/patent/US20140290802A1 ## CPC - C23C 8/42: only one element being applied - C23C 8/80: After-treatment - C23C 22/08: Orthophosphates - C23C 22/47: containing also phosphates - C23C 22/83: Chemical after-treatment - 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) ## Abstract This surface treatment method comprises a rustproofing step, a rinsing step, and a cleaning step. In the rustproofing step, a rustproofing liquid containing orthophosphoric acid and an organic acid is used to perform a rustproofing treatment on the surface of a steel material. In the rinsing step, a treatment liquid containing an oxo acid salt of a transition metal is used to perform a rinsing treatment on the surface of the steel material. In the cleaning step, the surface of the steel material that has undergone the rinsing step is subjected to a cleaning treatment. ## Claims ### Claim 1 A surface treatment method for a steel material, comprising: a rustproofing step of using a rustproofing liquid containing orthophosphoric acid and an organic acid to perform a rustproofing treatment on the a surface of a steel material; a rinsing step of using a treatment liquid containing an oxo acid salt of a transition metal to perform a rinsing treatment on the surface of the steel material; and a cleaning step of subjecting the surface of the steel material that has undergone the rinsing step to a cleaning treatment. ### Claim 2 (depends on 1) The surface treatment method for a steel material according to claim 1, further comprising a degreasing step of using a degreasing liquid to remove oil and grease from the surface of the steel material. ### Claim 3 (depends on 2) The surface treatment method for a steel material according to claim 2, further comprising a first water washing step of washing the surface of the steel material that has undergone the degreasing step. ### Claim 4 (depends on 1) The surface treatment method for a steel material according to claim 1, further comprising a second water washing step of using a treatment liquid containing orthophosphoric acid and an organic acid to wash the surface of the steel material that has undergone the rustproofing step. ### Claim 5 (depends on 1) The surface treatment method for a steel material according to claim 1, further comprising a spray step of spraying water on the surface of the steel material that has undergone the cleaning step. ### Claim 6 (depends on 1) The surface treatment method for a steel material according to claim 1, wherein a treatment liquid containing sodium dihydrogen phosphate dihydrate, a fluorine-based surfactant, and special modified ionized water is used in the rustproofing step and the second water washing step. ### Claim 7 (depends on 1) The surface treatment method for a steel material according to claim 1, wherein a treatment liquid containing an oxo acid salt of a transition metal and special modified ionized water is used in the rinsing step. ### Claim 8 (depends on 1) The surface treatment method for a steel material according to claim 1, wherein an oxo acid salt of a transition metal contained in the treatment liquid used in the rinsing step is either a tungstate, a molybdate, or a zirconate. ### Claim 9 (depends on 1) The surface treatment method for a steel material according to claim 1, wherein rustproofing of the steel material and a phosphate coating treatment are carried out simultaneously in the rustproofing step. ### Claim 10 (depends on 1) The surface treatment method for a steel material according to claim 1, wherein the first water washing step is repeated a plurality of times. ### Claim 11 (depends on 1) The surface treatment method for a steel material according to claim 1, wherein ultrasonic waves or a spray is used in the second water washing step. ### Claim 12 (depends on 1) The surface treatment method for a steel material according to claim 1, further comprising: a coating step of subjecting the steel material to a coating treatment. ### Claim 13 (depends on 12) The surface treatment method for steel material according to claim 12, further comprising producing a machine component with the steel material following the coating step. ### Claim 14 (depends on 13) The surface treatment method for a steel material according to claim 13, wherein the machine component is a hydraulic line for a hydraulic excavator.