Retrogression Heat Treatment

Abstract

A method for producing a product includes the steps of taking heated and cooled extrusion, preferably aluminum, and reheating a selected area of the extrusion. There is the step of requenching the extrusion. There is the step of forming the reheated area into a desired shape. A method for producing a ladder.

What is claimed is: 
     
         1 . A method for producing a product comprising the steps of:
 taking heated and cooled extrusion and reheating a selected area of the extrusion;   requenching the extrusion;   forming the reheated area into a desired shape; and   attaching the extrusion at the area directly with a member made of a different material than the extrusion.   
     
     
         2 . A method as described in  claim 1  wherein the extrusion is aluminum and the forming step includes the step of forming the reheated area into the desired shape within five days of requenching. 
     
     
         3 . A method as described in  claim 2  wherein the taking step includes the step of reheating the area to at least 550° F. 
     
     
         4 . A method as described in  claim 3  wherein the reheating step includes the step of reheating the area at a rate of 5°-95° F. per second. 
     
     
         5 . A method as described in  claim 4  wherein the reheating step includes the step of reheating the area to at least 550° F. within 10-75 seconds. 
     
     
         6 . A method as described in  claim 5  wherein the attaching step includes the step of attaching the extrusion at the area directly with the member without any additional piece. 
     
     
         7 . A method as described in  claim 6  wherein before the taking step, there is the step of press solution heat treating the extrusion. 
     
     
         8 . A method as described in  claim 7  wherein before the taking step, there is the step of quenching the extrusion rapidly enough to retain alloying elements in the extrusion in solution. 
     
     
         9 . A method as described in  claim 8  wherein before the taking step, there is a step of stretching the extrusion. 
     
     
         10 . A method as described in  claim 9  wherein before the taking step, there is the step of artificially aging with precipitation heat treatment the extrusion. 
     
     
         11 . A method as described in  claim 10  wherein the reheating step includes the step of reheating the end of the extrusion in an induction coil. 
     
     
         12 . A method as described in  claim 11  wherein before the taking step, there is the step of casting a log from molten alloyed aluminum. 
     
     
         13 . A method as described in  claim 12  wherein before the taking step, there is the step of homogenizing the log at a temperature greater than 900° F. for several hours. 
     
     
         14 . A method as described in  claim 13  wherein before the taking step, there is the step of cutting the log into billets after the log is quenched. 
     
     
         15 . A method as described in  claim 14  wherein the extrusion is a rung and a member is a ladder rail, and the attaching step includes a step of attaching the rung at the area directly with the ladder rail without any additional piece. 
     
     
         16 . A method as described in  claim 15  wherein the attaching step includes the step of forming a joint out of the rung with the rail. 
     
     
         17 . A method as described in  claim 16  wherein the attaching step includes the step of inserting rivets through the rung and the rail to attach the rung to the rail. 
     
     
         18 . A method for producing a product comprising the steps of:
 taking heated and cooled aluminum extrusion and reheating a selected area of the extrusion to afford a 20% or more improvement in material ductility relative to the pre-reheated but cooled extrusion, assisting forming operations used to assemble or join with other components of the same material or in combination with differing materials in the product;   requenching the extrusion; and   forming the reheated area into a desired shape.   
     
     
         19 . A method for producing a product comprising the steps of:
 taking heated and cooled aluminum extrusion and reheating a selected area of the extrusion to afford a 20% or more improvement in material ductility relative to the pre-reheated but cooled extrusion, assisting forming and assembly operations to complete joints by providing joining geometries for traditional fasteners;   requenching the extrusion; and   forming the reheated area into a desired shape.   
     
     
         20 . A method for producing a ladder comprising the steps of:
 taking heated and cooled aluminum extrusion and reheating a selected area of the extrusion;   requenching the extrusion;   forming the reheated area into a rung; and   attaching the rung to a rail.