Method and system for producing aluminum alloy parts

Abstract

In production of aluminum alloy members by a plastic working of a heat-treatable aluminum alloy extrusion, cracking during the plastic working is eliminated or minimized at low cost as compared with techniques including solution treatment or restoration treatment. An aluminum alloy production system includes an extruding press, a cutting device disposed downstream from the extruding press, and a conveyer and a plastic working machine each disposed in parallel with the extruding press. The extruding press hot-extrudes a heat-treatable aluminum alloy to give an extrusion. The cutting device cuts the extrusion to a predetermined length and isolates the extrusion from the extruding press. The conveyer conveys the extrusion to the plastic working machine, where the extrusion has been cut by the cutting device to a predetermined length. The plastic working machine imparts a plastic working to the extrusion conveyed by the conveyer to form the extrusion into an aluminum alloy part.

Description

FIELD OF INVENTION[0001]The present invention relates to a method for producing aluminum alloy parts through plastic working of heat-treatable aluminum alloy extrusions, and to a production system suitable for carrying out the method.BACKGROUND OF INVENTION[0002]Automobile parts such as collision protectors (e.g., bumper reinforcements) and body frames require higher strengths due to recent enhancement of automobile crash safety standards and pedestrian protection standards. On the other hand, the automobile parts also require lower weights due to demands for higher maneuverability and higher fuel efficiency. To have higher strengths and lower weights, some of these automobile parts are made from heat-treatable aluminum alloy extrusions. The extrusions may undergo a plastic working such as bending or crushing for higher design freedom and smaller number of parts.[0003]An exemplary conventional method and system for producing an aluminum alloy member (a bumper reinforcement, herein) ...

AI Technical Summary

Benefits of technology

The present invention provides an improved method for producing aluminum alloy parts through plastic working of heat-treatable aluminum alloy extrusions. The method includes a cutting and plastic working process without the need for solution treatment and restoration treatment, which reduces costs and increases efficiency. The method also includes a cooling process that allows the extrusion to have uniform properties and higher strength after temper aging. The invention aims to minimize cracking and improve the yield strength and elongation of plastic working while also reducing residual stress and improving stress corrosion cracking resistance of the resulting parts.

Problems solved by technology

Unfortunately, the extrusions have lower elongations due to progress of natural aging and suffer from rupture and / or cracking when undergoing plastic working with large deformation.

This disadvantageously causes lower dimensional accuracy.

The aluminum alloys suffer from these disadvantages more with an increasing strength of the materials (alloys).

Disadvantageously, however, these treatments require reheating and cooling of the extrusions immediately before plastic working, and this causes increased spending on heat treatment facilities and additional steps and causes increased cost.

Disadvantageously, however, the inner ribs, which are not directly cooled from the outer periphery, undergo insufficient quenching due to delayed temperature fall, and the extrusions fail to have a predetermined strength after artificial aging.

In addition, the extrusions after cooling disadvantageously have large deformation due to difference in thermal shrinkage, because of uneven temperature distribution in the cross section during cooling.

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