# US 8,784,579 B2 · Magnesium grain refining using vanadium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,579 B2 - Document ID: US8784579B2 - Status: Granted - Kind: B2 - Application number: 12/936,910 - Filed: 2009-04-20 - Published: 2011-02-17 - Granted: 2014-07-22 - Earliest claimed: 2008-04-22 - Applicants: Joka Buha - Inventors: Joka Buha - Web page: https://patentgrep.com/patent/US8784579B2 ## CPC - C22B 26/22: Obtaining magnesium - C22B 9/10: with refining or fluxing agents; Use of materials therefor, {e.g. slagging or scorifying agents}(C22B9/18 takes precedence){(C22B9/006 takes precedence)} - C22C 1/06: with the use of special agents for refining or deoxidising - C22C 23/04: with zinc or cadmium as the next major constituent - C22F 1/06: of magnesium or alloys based thereon - C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS - C22C: ALLOYS (treatment of alloys C21D, C22F) - 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) ## Abstract A process of grain refining magnesium metal or magnesium based alloy including the step of a) providing a melt of the magnesium metal or magnesium based alloy, said melt including a grain refining agent in an amount effective to induce grain refinement of said magnesium or magnesium based alloy upon solidification, wherein the grain refining agent is vanadium metal, where said grain refinement comprises a reduction in average grain size of at least 50% (percent) as compared with the average grain size without addition of said grain refining agent. ## Claims ### Claim 1 A process of grain refining magnesium metal or magnesium based alloy including the step of a) providing a melt of the magnesium metal or magnesium based alloy, said melt including a grain refining agent in an amount effective to induce grain refinement of said magnesium metal or magnesium based alloy upon solidification, where said grain refinement in the solidified magnesium metal or magnesium based alloy comprises a reduction in average grain size of at least 50% (percent) as compared with the average grain size without addition of said grain refining agent; wherein melting of the magnesium metal or magnesium based alloy is conducted at a temperature of at least 670° C., and the melt is held at the melting temperature for a period of time sufficient to allow for the grain refining agent to become active; wherein the grain refining agent is vanadium metal added in the form of pure or elemental vanadium metal, or the grain refining agent is vanadium metal added in the form of a master alloy or pre-alloy of vanadium with one or more alloying elements present in the magnesium based alloy which is being grain refined; wherein the grain refining agent is added to the magnesium metal or magnesium based alloy after formation of the melt; or the grain refining agent is added to the magnesium metal or magnesium based alloy prior to formation of the melt; and the grain refining agent is added to said magnesium metal or magnesium based alloy in an amount of up to 2 wt % (weight percent) equivalent of vanadium metal. ### Claim 2 (depends on 1) The process of claim 1, where the amount of the grain refining agent is additionally effective to inhibit grain growth during a subsequent heat treatment of the solidified magnesium metal or magnesium based alloy. ### Claim 3 (depends on 1) The process of claim 1 further including stirring of the melt of magnesium metal or magnesium based alloy containing the grain refining agent where the said stirring is conducted mechanically or by induction heating. ### Claim 4 (depends on 1) The process of claim 1 in which the magnesium metal or magnesium based alloy is melted at a temperature between 670° C. and 800° C. ### Claim 5 (depends on 1) The process of claim 1 in which the melt is held at the melting temperature for a period of time of at least 5 minutes. ### Claim 6 (depends on 1) The process of claim 1 in which the grain refining agent is added to said magnesium metal or magnesium based alloy in an amount of about 0.005 to 0.3 wt % (weight percent) equivalent of vanadium metal. ### Claim 7 (depends on 1) The process of claim 1 including the further steps of: b) subjecting the solidified magnesium based alloy to a first heat treatment at a temperature for a time sufficient to effect the dissolution of the alloying elements into magnesium solid solution; c) quenching; and d) subjecting the quenched magnesium based alloy to a second heat treatment sufficient to result in the formation of clusters or precipitates containing alloying elements throughout the alloy grains which were at least partially nucleated by vanadium metal present in the magnesium solid solution. ### Claim 8 (depends on 7) The process of claim 7 where the first heat treatment is conducted at a temperature of 5° C. to 50° C. below the melting point of the magnesium based alloy for a time of at least 30 minutes. ### Claim 9 (depends on 7) The process of claim 7, where the temperature of the second heat treatment is below 280° C. ### Claim 10 (depends on 7) The process of claim 7, where the temperature of the second heat treatment is above 100° C. ### Claim 11 (depends on 1) The process of claim 1 in which the melt is held at the melting temperature for a period of time of 5 to 10 minutes. ### Claim 12 (depends on 7) The process of claim 7, where the temperature of the second heat treatment is above 150° C. ### Claim 13 (depends on 7) The process of claim 7, where the temperature of the second heat treatment is above 170° C. ### Claim 14 (depends on 10, 12, 13) The process of claim 10 or 12 or 13 where the second heat treatment is conducted for at least 20 minutes.