# US 10,501,834 B2 · Method for reducing the speed of propagation of a crack in a metal substrate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,501,834 B2 - Document ID: US10501834B2 - Status: Granted - Kind: B2 - Application number: 15/153,091 - Filed: 2016-05-12 - Published: 2016-12-01 - Granted: 2019-12-10 - Earliest claimed: 2015-06-01 - Assignees: Helmholtz-Zentrum Geesthacth Zentrum für Material-und Küstenforschung GmbH - Applicants: Helmholtz-Zentrum Geesthacht Zentrum für Material- und Küstenforschung GmbH - Inventors: Anne Groth; Nikolai Kashaev; Norbert Huber - Web page: https://patentgrep.com/patent/US10501834B2 ## CPC - C22F 1/04: of aluminium or alloys based thereon - B23K 26/0006: {taking account of the properties of the material involved (B23K26/32, B23K26/40 take precedence)} - B23K 26/035: Aligning the laser beam (automatically B23K26/042) - B23K 26/352: for surface treatment - B23P 6/04: Repairing fractures or cracked metal parts or products, e.g. castings - C21D 1/09: by direct application of electrical or wave energy; by particle radiation - C22F 3/00: Changing the physical structure of non-ferrous metals or alloys by special physical methods, e.g. treatment with neutrons - B23K 2101/006: {Vehicles} - B23K 2103/04: Steel {or steel} alloys - B23K 2103/10: Aluminium or alloys thereof - B23K 2103/14: Titanium or alloys thereof - B23K 2103/15: {Magnesium or alloys thereof} - C21D 2221/00: Treating localised areas of an article - C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (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) - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - B23P: METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS (arrangements for copying or controlling B23Q) - 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) ## Abstract A method for reducing the speed of propagation of a crack in a metal substrate by means of laser heat treatment can include heating the metal substrate with a laser heat treatment at one or more crack ends, wherein the laser beam is guided over the substrate surface so that it defines the form of an oval, an arc or a curve. Alternatively, the substrate can be treated by means of laser heat treatment before a crack arises. For example, areas at risk of cracking are identified in a metal substrate and the metal substrate is then heated by means of laser heat treatment in these areas, wherein the laser beam is guided over the substrate surface so that it defines the form of an oval, an arc or a curve. Also disclosed herein are metal substrates produced by the method and the use thereof. ## Claims ### Claim 1 A method for reducing the speed of propagation of a crack in a metal substrate, comprising: (a) identifying a crack in the metal substrate, wherein the crack has two or more crack ends; and (b) heating the metal substrate using a laser heat treatment by guiding a laser beam over a surface of the metal substrate, at one or more crack ends, to thereby heat the surface in the propagation directions of the crack, wherein the laser beam is guided over the surface of the metal substrate in a path having a shape of an oval, an arc, or a curve, and the metal surface is heated to a temperature of about 300° C. to a temperature below the melt temperature of the metal substrate. ### Claim 2 A method for reducing the speed of propagation of a crack in a metal substrate, comprising: (a) identifying areas at risk of cracking in a metal substrate; and (b) heating the metal substrate using a laser heat treatment by guiding a laser beam over a surface of the metal substrate, in the identified areas at risk of cracking, before a crack arises, to thereby heat the surface in expected crack propagation directions, wherein the laser beam is guided over the surface of the metal substrate in a path having a shape of an oval, an arc, or a curve, and the metal surface is heated to a temperature of about 300° C. to a temperature below the melt temperature of the metal substrate. ### Claim 3 (depends on 1) The method according to claim 1, wherein the path has the shape of an oval. ### Claim 4 (depends on 3) The method according to claim 3, wherein the oval is a circle or an ellipsis. ### Claim 5 (depends on 1) The method according to claim 1, wherein the crack has two crack ends and the the laser beam is guided over the surface of the metal substrate at both crack ends to thereby heat the surface in the propagation direction of the crack. ### Claim 6 (depends on 5) The method according to claim 5, wherein the laser beam is guided in a path at both crack ends that has the shape of a circle to form circles at each crack end. ### Claim 7 (depends on 6) The method according to claim 6, wherein the circles each has a diameter of 3 mm to 7 mm, and a mid-point distance between the circles is 20 mm to 30 mm. ### Claim 8 (depends on 1) The method according to claim 1, wherein the metal substrate is an aluminium alloy. ### Claim 9 (depends on 8) The method according to claim 8, wherein the metal substrate is heated to a temperature between 300° C. and 800° C. ### Claim 10 (depends on 4) The method of claim 4, wherein the oval is a circle. ### Claim 11 (depends on 7) The method of claim 7, wherein the circles each have a diameter of 4 mm to 6 mm. ### Claim 12 (depends on 7) The method of claim 7, wherein the circles each has a diameter of approximately 5 mm. ### Claim 13 (depends on 7) The method of claim 7, wherein the mid-point distance is approximately 25 mm. ### Claim 14 (depends on 9) The method of claim 9, wherein the metal substrate is heated to a temperature between 400° C. and 700° C. ### Claim 15 (depends on 9) The method of claim 9, wherein the metal substrate is heated to approximately 600° C.