RU2186654C1 - Method for recovery of crystallizer working wall - Google Patents

Abstract

FIELD: metallurgy. SUBSTANCE: method involves providing shotblasting of worn portions of crystallizer walls made from copper or alloys thereof and adjoining to crystallizer corners arranged in lower parts of wall working surfaces; performing gaseous and thermal deposition of wear-resistant coat based on copper-nickel alloys. Coat deposition is initiated at area having wearing depth of at least 0.5-0.6 mm, and thickness of deposited layer does not exceed wearing depth. It is recommended that fire-resistant daub layer be applied to said area upon termination of coat deposition process. Recovery work may be performed without disassembling of crystallizer. EFFECT: decreased consumption of coating material and reduced probability of delaminating thereof. 4 cl

Description

 The invention relates to the field of metallurgy and can be used to restore the working walls of the mold without disassembling it.

 Closest to the proposed method is the restoration of the working walls of the mold without disassembling it, including bead-blasting of worn sections adjacent to the corners of the mold and located in the lower part of the working surfaces of the walls made of copper or its alloys, and thermal spraying on them a wear-resistant coating based on copper -nickel alloys (patent 2119404, Russia, 06/26/97, MKI: B 22 D 11/04). However, this method is characterized by increased consumption of coating material, caused by its spraying on worn areas up to 3.0 mm deep, beyond the worn areas.

 The objective of the invention is to improve the technology of restoration of the working walls of the mold without disassembling it. In this case, the technical result is a reduction in the coating material and a decrease in the probability of its delamination.

 In the method of restoring the working walls of the mold without disassembling it, including bead-blasting of worn sections adjacent to the corners of the mold and located in the lower part of the working surfaces of the walls made of copper or its alloys, and thermal spraying them with a wear-resistant coating based on copper-nickel alloys, according to the invention, the coating is sprayed starting from a wear depth of at least 0.5-0.6 mm, with a thickness not exceeding the wear depth. After spraying the coating, heat-resistant grease is applied to it.

 With a wear depth of not less than 0.5-0.6 mm, the width of the wear zone is not less than the width of the spraying strip and the entire coating is placed in a worn place. This circumstance, as well as the spraying of the coating with a thickness not exceeding the wear depth, leads to a reduction in the consumption of the sprayed material and a decrease in the likelihood of delamination of the coating when the seed passes through the mold. When the wear depth is less than 0.5-0.6 mm, the width of the wear zone is less than the width of the spraying strip and the coating goes beyond the worn place. If the coating does not extend beyond the zone of shot blasting, then excess coating is removed during the casting of the first heat. Otherwise, the coating peels off. In addition, spraying the coating into the wear region with a depth of less than 0.5-0.6 mm is impractical, since due to the concavity of the crystallized ingot, the wear reaches this depth for a small number of melts, until the ingot completely adheres along the width of the mold walls. For this reason, the coating thickness is less than the wear depth by at least 0.5-0.6 mm.

 When spraying a coating with a thickness exceeding the depth of wear, excess coating is also removed during the casting of the first heat. This leads to overuse of the coating material.

 When coating is sprayed with a thickness not exceeding the wear depth, during casting on its rough surface there remains a heat-resistant lubricant applied after spraying, which reduces wear on the working surfaces of the mold walls.

 Example. The walls of the mold were reconstructed with a section of 250 • 1850 mm without disassembling it after being put into reserve. Depreciation occurred in the lower part of the working surfaces adjacent to the corners of the mold up to a length of 300 mm, a width of 50 mm and a depth that increased in the direction of the metal to 1.5 mm. After bead-blasting treatment of the wear region, a coating was sprayed onto the wear region of the MNZHKT alloy using an EM-14M electric arc metallizer. The coating thickness was up to 1.0 mm. The spray areas were treated with graphite based grease.

 In this example, we obtained savings in coating material, because Depth of wear was not less than 0.5-0.6 mm, i.e. the width of the wear area was not less than the width of the spraying strip of 20-30 mm, and the entire coating fell into the area of wear. In addition, the thickness of the sprayed coating did not exceed the depth of wear.

Claims (3)

 1. The method of restoring the working walls of the mold without disassembling it, including bead-blasting of worn sections adjacent to the corners of the mold and located in the lower part of the working surfaces of the walls made of copper or its alloys, and thermal spraying on them a wear-resistant coating based on copper-nickel alloys characterized in that the coating is sprayed, starting from a wear depth of at least 0.5-0.6 mm, with a thickness not exceeding the wear depth.  2. The method according to claim 1, characterized in that after spraying the coating, a heat-resistant lubricant is applied to it.  3. The method according to claim 1, characterized in that the coating is sprayed with a thickness less than the depth of wear by at least 0.5-0.6 mm.