Retrogression heat treatment
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.
1. A method for producing a product comprising the steps of:
heating an extrusion;
cooling the extrusion;
taking the heated and cooled extrusion and reheating a selected area of the extrusion to approximately 700° to 750° F. at a rate of 45° to 50° F. per second in about 15 seconds;
immediately requenching the extrusion after reheating the extrusion;
forming the reheated area into a desired shape; and
attaching the selected area of the extrusion directly with a member without any additional piece.
2. A method as described in claim 1 wherein before the taking step, there is the step of press solution heat treating the extrusion.
3. A method as described in claim 2 wherein before the taking step, there is the step of quenching the extrusion rapidly enough to retain alloying elements in the extrusion in solution.
4. A method as described in claim 3 wherein the reheating step includes the step of reheating the end of the extrusion in an induction coil.
5. A method as described in claim 4 wherein before the taking step, there is the step of casting a log from molten alloyed aluminum.
6. A method as described in claim 5 wherein before the taking step, there is the step of homogenizing the log at a temperature greater than 900° F. for several hours.
7. A method as described in claim 6 wherein before the taking step, there is the step of cutting the log into billets after the log is quenched.
8. A method as described in claim 7 wherein before the taking step, there is the step of preheating and extruding the log into a desired cross-section to form the extrusion.
9. A method as described in claim 8 wherein before the taking step, there is the step of cutting the extrusion to a desired length.
10. A method as described in claim 9 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.
11. A method as described in claim 10 wherein the attaching step includes the step of forming a joint out of the rung with the rail.
12. A method of claim 1 wherein the attached step includes the step of attaching the selected area of the extrusion directly with a member made of a different material than the extrusion without any additional piece.