Shaped metal container, microstructure, a method for making a shaped metal container
The principles of the present invention further provide both a shaped metal container and its preforms that exhibit a rounded grain structure characteristic created by an annealing process and a method for making a shaped metal container. The process of making said metal container results in a quicker process time and uses less metals (at least 10% metal weight savings), thus allowing for a decrease in the costs of making such shaped metal containers. A shaped metal container may include work hardened rolled sheet-metal defining a sidewall, an opening, and a base, where at least one section along the sidewall has grains with an average aspect ratio less than about 4 to 1.
1. A method for making a shaped metal container, the container including a container middle section having at least one middle section diameter Dm, the container middle section being connected at one end to a container bottom section having at least one bottom section diameter Db, and at the other end connected to a container top section having a container opening, and having at least one top section diameter Dt, the method comprising:
providing a container preform having a cylindrical body with a diameter Dc;
inwardly shaping by necking at least a section of the cylindrical body;
annealing at least a section to be inwardly or outwardly shaped, wherein annealing is performed such that at least a section has a rounded grain structure with an average aspect ratio in the range of less than 4 to 1, wherein the rounded grain structure is created by the annealing;
outwardly shaping at least a section of the cylindrical body;
wherein at least one of the middle section diameter Dm, the bottom section diameter Db, and the top section diameter Dt is greater than the cylinder diameter Dc of the container preform; and
wherein at least one of the middle section diameter Dm, the bottom section diameter Db, and the top section diameter Dt, is smaller than the cylinder diameter Dc of the container preform.
2. The method according to claim 1 , wherein annealing at least a section causes a rounded grain structure with an average aspect ratio in the range of less than 2 to 1.
3. The method according to claim 1 , wherein outwardly shaping is performed by blow forming.
4. The method according to claim 1 , further comprising applying an axial compression onto the container preform during the blow forming.
5. The method according to claim 1 , wherein annealing is performed by induction annealing before outwardly shaping.
6. The method according to claim 1 , further comprising forming the container top section by necking.
7. The method according to claim 1 , further comprising forming a thread and/or a bead in the necked top section, and at least one of the thread and bead includes at least one axial interruption.
8. The method according to claim 1 , wherein after necking or outwardly shaping the container top section, the method further comprises trimming, and curling the container opening.
9. The method according to claim 1 , wherein the container middle section is provided with inwardly and/or outwardly extending strengthening or aesthetic structures.
10. The method according to claim 1 , wherein the shaped metal container is a one-piece container.
11. The method according to claim 10 , wherein the one-piece container is a metal beverage bottle.
12. The method according to claim 10 , wherein the one-piece container is a metal aerosol container.
13. The method according to claim 1 , wherein the container comprises a base that is connected to the container bottom section, wherein the base is not annealed.