Moderate temperature bending of magnesium alloy tubes
View Patent ↗A method for bending magnesium alloy tubes. The method includes heating the tube at moderate temperature in the range of about 100° C. to 200° C., and bending the tube to a bend angle or forming the tube to a desired shape.
1. A method for bending a magnesium alloy tube, the method comprising:
heating the tube at a moderate temperature in the range of about 100° C. to 200° C.; and
bending the tube to a bend angle, wherein said bending at said moderate temperature range provides a bend quality having one or more properties selected from the group consisting of: a maximum surface defect variance of less than or equal to about 5, a maximum % thinning variance of less than or equal to about 42, a standard deviation of % thinning of less than or equal to about 8.5, and combinations thereof.
2. The method of claim 1 , wherein heating the tube comprises:
heating a tooling; and
holding the tube in the tooling until it is heated to the moderate temperature.
3. The method of claim 1 , further comprising placing the tube over a mandrel.
4. The method of claim 3 , wherein bending the tube comprises:
positioning the tube between a pressure die and a bend die;
applying pressure with the pressure die; and
rotating the bend die.
5. The method of claim 1 , wherein bending the tube comprises bending the tube to a bend radius that is at least twice an outside diameter of the tube.
6. The method of claim 1 , wherein bending the tube comprises bending the tube to a bend radius that is less than twice an outside diameter of the tube.
7. The method of claim 5 , wherein the bend angle is 90°.
8. The method of claim 7 , wherein the magnesium alloy is AM30.
9. The method of claim 7 , wherein the magnesium alloy is AZ31B.
10. The method of claim 1 , wherein the moderate temperature is in the range of about 125° C. to 175° C.
11. The method of claim 1 , wherein the moderate temperature is about 150° C.
12. The method of claim 2 , further comprising holding the tube in the tooling for about one minute before bending.
13. The method of claim 2 , further comprising holding the tube in the tooling for about five minutes before bending.
14. The method of claim 2 , wherein the tooling comprises a mandrel, a pressure die and a bend die.
15. The method of claim 1 , further comprising lubricating the tube.
16. The method of claim 1 , wherein bending comprises bending by rotary draw.
17. The method of claim 1 , wherein bending comprises hydroforming.
18. The method of claim 1 , wherein bending comprises compression bending.
19. The method of claim 1 , wherein bending comprises roll bending.
20. The method of claim 1 , wherein the magnesium alloy comprises over 80% magnesium.
21. A magnesium alloy tube bent by the method of claim 1 .
22. A method for forming a magnesium alloy tube, the method comprising:
heating the tube at a moderate temperature in the range of about 100° C. to 200°; and
forming the tube to a desired shape, wherein said forming at said moderate temperature range provides a bend quality having a maximum surface defect variance of less than or equal to about 5.
23. The method of claim 21 , wherein forming includes bending at a bend angle.