WO2024091271A1

WO2024091271A1 - Hot-stamping aluminum formation process

Info

Publication number: WO2024091271A1
Application number: PCT/US2022/078877
Authority: WO
Inventors: Andrew Charles NISBET; Subhojit CHAKRABORTY; Daniel Jefferson MUIR; Mehdi GOLOZAR; Kevin MIRON
Original assignee: Atieva, Inc.
Priority date: 2022-10-28
Filing date: 2022-10-28
Publication date: 2024-05-02

Abstract

A hot-stamping aluminum formation process comprises: subjecting an aluminum panel to solutionizing, forming and quenching in a stamping die during a first stage, the first stage performed for a first time period and including a second time period of about 2-6 minutes when the aluminum panel is subjected to a temperature of about 540-550 degrees Celsius, the first stage also including in-die quenching of the aluminum panel after the second time period; and subjecting the aluminum panel to pre-aging during a second stage after the first stage, the second stage including a third time period of about 30-60 minutes when the aluminum panel is subjected to a temperature of about 200-210 degrees Celsius.

Description

HOT-STAMPING ALUMINUM FORMATION PROCESS

TECHNICAL FIELD

[0001] This document relates to a hot-stamping aluminum formation process.

BACKGROUND

[0002] Modern vehicle designs are influenced by the increasing emphasis on vehicle crash safety that characterizes today’s automotive manufacturing industry. For protection against side impacts on a vehicle, some different energy absorption mechanisms have been used. With the arrival of electric vehicles, protection of a battery pack positioned underneath the vehicle body also has become an important goal. Previous approaches in vehicle side impact protection have sometimes been based on extruded material such as aluminum. However, an extrusion process provides a rail with a constant profile that may not be adapted to tune the impact protection or conform to the particular design of the vehicle body.

SUMMARY

[0003] In an aspect, a hot-stamping aluminum formation process comprises: subjecting an aluminum panel to solutionizing, forming and quenching in a stamping die during a first stage, the first stage performed for a first time period and including a second time period of about 2-6 minutes when the aluminum panel is subjected to a temperature of about 540-550 degrees Celsius, the first stage also including in-die quenching of the aluminum panel after the second time period; and subjecting the aluminum panel to pre-aging during a second stage after the first stage, the second stage including a third time period of about 30-60 minutes when the aluminum panel is subjected to a temperature of about 200- 210 degrees Celsius.

[0004] Implementations can include any or all of the following features. The first stage and the second stage form a stamped panel for an energy absorption side structure for a vehicle, the stamped panel having a series of ridges each extending substantially perpendicular to a longitudinal axis of the stamped panel. The aluminum panel includes: about 0.40-1.00% Mn, about 0.0-0.50% Fe, about 0.60-1.20% Mg, about 0.70-1.30% Si, about 0.0-0.10% Cu, about 0.0-0.20% Zn, about 0.0-0.10% Ti, about 0.0-0.25% Cr, about 0.0-0.15% residual material(s), and a balance of aluminum. The first time period is about 12 minutes. The second time period is about 3-5 minutes. The second time period is about 4 minutes. The in-die quenching is performed for a fourth time period shorter than the second time period. The first stage further includes a temperature increase stage when the aluminum panel is being heated to the temperature of about 540-550 degrees Celsius, and wherein the in-die quenching is performed for a fourth time period shorter than the temperature increase stage. The hot-stamping aluminum formation process further comprises performing natural aging of the aluminum panel during a third stage directly after the second stage, the natural aging performed with the aluminum panel removed from the die. The hot-stamping aluminum formation process further comprises subjecting the aluminum panel to a holding period between the second time period and the in-die quenching. The second stage lasts for about 70-80 minutes. The second stage lasts for about 75 minutes. The hot-stamping aluminum formation process further comprises performing painting and baking of the aluminum panel after the second stage. The hot-stamping aluminum formation process further comprises assembling the aluminum panel with another aluminum panel after the second stage and before performing the painting and baking. The third time period is about 40-50 minutes. The third time period is about 45 minutes.

BRIEF DESCRIPTION OF DRAWINGS

[0005] FIG. 1 shows an example of a hot-stamping aluminum formation process.

[0006] FIG. 2 shows an example of a press that can be used for the hot-stamping aluminum formation process of FIG. 1

[0007] FIG. 3 shows an example of an energy absorption side structure for a vehicle including stamped panels.

[0008] FIG. 4 shows an example of one of the stamped panels of the energy absorption side structure of FIG. 3.

[0009] Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0010] This document describes examples of systems and techniques providing an improved hot-stamping aluminum formation process. In some implementations, the hot- stamping aluminum formation process can be used in manufacturing energy absorption side structures for vehicles.

[0011] Examples herein refer to a vehicle. A vehicle is a machine that transports passengers or cargo, or both. A vehicle can have one or more motors using at least one type of fuel or other energy source (e.g., electricity). Examples of vehicles include, but are not limited to, cars, trucks, and buses. The number of wheels can differ between types of vehicles, and one or more (e.g., all) of the wheels can be used for propulsion of the vehicle, or the vehicle can be unpowered (e.g., when a trailer is attached to another vehicle). The vehicle can include a passenger compartment accommodating one or more persons.

[0012] Examples described herein refer to a top, bottom, front, side, or rear. These and similar expressions identify things or aspects in a relative way based on an express or arbitrary notion of perspective. That is, these terms are illustrative only, used for purposes of explanation,

[0013] FIG. 1 shows an example of a hot-stamping aluminum formation process 100. The process 100 can be used with one or more other examples described elsewhere herein. The process 100 is here illustrated using examples described with reference to a diagram where time is indicated on the horizontal axis and the temperature of an aluminum panel is indicated on the vertical axis. The process 100 can be performed on any of multiple different types of aluminum panels, including but not limited to, those described in examples further below.

[0014] The process 100 can begin with the aluminum panel at temper F, temperature as stamped. In a stage 102, the aluminum panel can be subjected to solutionizing, forming and quenching. The stage 102 can be performed in part before and in part while the aluminum panel is in a die for stamping. In short, the solutionizing can prepare the aluminum panel to a state suitable for being formed (e.g., by heating the panel before entering the die), and the panel can be formed accordingly and quenched to a lower temperature. The stage 102 can include a time period 102A where the aluminum panel is being heated. The heating can begin from a lower temperature, such as a temperature as stamped. The time period 102 A can have any of multiple lengths. For example, this is performed by heating the aluminum panel in an oven. The stage 102 can include a time period 102B where the aluminum panel is kept at a substantially constant temperature. In some implementations, the temperature in the time period 102B can be about 540-550 degrees Celsius (C), for example about 545 degrees C. The time period 102B can occur in the oven and can have any of multiple lengths. In some implementations, the time period 102B can be about 2-6 minutes. For example, the time period 102B can be about 3-5 minutes, such as about 4 minutes. The stage 102 can include a time period 102C representing a holding period. In some implementations, the blank is waiting to be transferred to the die in the time period 102C. For example, the blank can be held on a rack and the temperature can decrease somewhat. The stage 102 can include a time period 102D where the aluminum panel is formed in the die and subjected to in-die quenching. The in-die quenching can serve to arrest growth of precipitates in the aluminum panel so that it does not become brittle during the stamping. The in-die quenching can involve bringing the aluminum panel to a lower temperature than in the time periods 102B- 102C. For example, the aluminum panel can be brought to substantially the same temperature as at the beginning of the time period 102 A. The time period 102D can have any of multiple lengths. For example, the time period 102D can be shorter than the time period 102A. As another example, the time period 102D can be shorter than the time period 102B. The stage 102 can have any of multiple lengths. For example, the stage 102 can last for about 12 minutes.

[0015] In a stage 104, the aluminum panel can be subjected to pre-aging. The stage 104 can be performed while the aluminum panel is outside the die. The pre-aging (sometimes characterized as artificial aging) can serve to slowly impart strength to the material of the aluminum panel and provide a balance between strength and ductility. The stage 104 can include a time period 104A where the aluminum panel is transferred to the final aging oven. For example, this can be performed at a non-elevated temperature (e.g., room temperature). The time period 104A can have any of multiple lengths. In some implementations, the time period 104 A can last shorter than about 10 minutes. For example, The stage 104 can include a time period 104B where the temperature of the aluminum panel is being increased. The time period 104 A can occur directly before the time period 104B. The time period 104B can have any of multiple lengths. The stage 104 can include a time period 104C where the aluminum panel is kept at a substantially constant temperature. In some implementations, the temperature in the time period 104B can be about 200-210 degrees C, for example about 205 degrees C. The time period 104C can have any of multiple lengths. For example, the time period 104C can last about 30-60 minutes, such as about 40-50 minutes, for example 45 minutes. The stage 104 can include a time period 104D where the temperature of the aluminum panel is being decreased. The time period 104D can have any of multiple lengths. In some implementations, the time periods 104B, 104C, and 104D can last about 70-80 minutes, such as about 75 minutes. The stage 104 can include a time period 104E where the aluminum panel is subjected to natural aging. The time period 104E can occur directly after the time period 104D. The temperature should be stable during the time period 104E. The time period 104E can have any of multiple lengths. The stage 104 can have any of multiple lengths.

[0016] In a stage 106, the aluminum panel can be subjected painting and baking. This can serve to provide the aluminum panel (or an assembly of the panel, as the case may be) with one or more characteristics such as surface texture, oxidation protection, surface coloring, anti-slip protection, wear protection, and/or electrical insulation, to name just a few examples. The stage 106 can include a time period 106A where the aluminum panel is brought to a temperature of about 160-180 C, such as about 171 C, and is kept at that temperature for about 15-30 minutes, such as about 20 minutes. The stage 106 can include a time period 106B where the aluminum panel is brought to a temperature of about 140-160 C, such as about 149 C, and is kept at that temperature for about 5-15 minutes, such as about 10 minutes. The stage 106 can include a time period 106C where the aluminum panel is brought to a temperature of about 55-75 C, such as about 65 C, and is kept at that temperature for about 3-9 minutes, such as about 6 minutes. The stage 106 can include a time period 106D where the aluminum panel is brought to a temperature of about 130-150 C, such as about 140 C, and is kept at that temperature for about 20-30 minutes, such as about 25 minutes.

[0017] Two or more components including at least one aluminum panel manufactured according to the process 100 can be assembled at an assembly operation 108. In some implementations, two or more aluminum panels can be assembled. For example, two stamped panels can be assembled into an energy absorption side structure for a vehicle. At least one of such panels can have a series of ridges each extending substantially perpendicular to a longitudinal axis of the stamped panel.

[0018] The process 100 can begin with selecting an aluminum panel from suitable stock. Multiple different materials can be used, including but not limited to an aluminum alloy. The choice of material and/or the specifics of the hot-stamping process can affect material properties such as strength, elongation and/or ductility. In some implementations, the stamped panel can be made using 6xxx aluminum alloy. For example, the aluminum alloy can include: about 0.40-1.00% manganese (Mn), about 0.0-0.50% iron (Fe), about 0.60-1.20% magnesium (Mg), about 0.70-1.30% silicon (Si), about 0.0-0.10% copper (Cu), about 0.0-0.20% zinc (Zn), about 0.0-0.10% titanium (Ti), about 0.0-0.25% chromium (Cr), about 0.0-0.15% residual material(s), and a balance of aluminum.

[0019] FIG. 2 shows an example of a press 200 that can be used for the hot-stamping aluminum formation process of FIG. 1. The press 200 can be used with one or more other examples described elsewhere herein. The press 200 includes an upper die shoe 202 and a lower die shoe 204. The press 200 includes a die 206 that is here mounted to the upper die shoe 202. The die 206 defines at least one draw cavity 208 into which an aluminum panel 210 will be drawn during the stamping using a punch 212 mounted to the lower die shoe 204. At least one binder 214 can be applied to the aluminum panel 210 during the stamping.

[0020] FIG. 3 shows an example of an energy absorption side structure 300 for a vehicle including stamped panels. FIG. 4 shows an example of one of the stamped panels of the energy absorption side structure 300 of FIG. 3. The energy absorption side structure 300 can be used with one or more other examples described elsewhere herein. The energy absorption side structure 300 includes a stamped panel 302 and a stamped panel 304. Either or both of the stamped panels 302 or 304 can be formed using the process 100 in FIG. 1. The stamped panel 304 is assembled to the stamped panel 302 to form an enclosed space. The stamped panel 302 can have one or more ridges 306 formed by the stamping (e.g., a series of the ridges 306). Each of the ridges 306 extends substantially perpendicular to a longitudinal axis of the stamped panel 302. The stamped panel 304 can also or instead have one or more ridges. For example, such ridge(s) can be different from, or substantially identical to, the ridge(s) 306.

[0021] The terms “substantially” and “about” used throughout this Specification are used to describe and account for small fluctuations, such as due to variations in processing. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Also, when used herein, an indefinite article such as "a" or "an" means "at least one."

[0022] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein.

[0023] A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the specification.

[0024] In addition, the logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. In addition, other processes may be provided, or processes may be eliminated, from the described flows, and other components may be added to, or removed from, the described systems. Accordingly, other implementations are within the scope of the following claims.

[0025] While certain features of the described implementations have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that appended claims are intended to cover all such modifications and changes as fall within the scope of the implementations. It should be understood that they have been presented by way of example only, not limitation, and various changes in form and details may be made. Any portion of the apparatus and/or methods described herein may be combined in any combination, except mutually exclusive combinations. The implementations described herein can include various combinations and/or sub-combinations of the functions, components and/or features of the different implementations described.

Claims

What is claimed is:

1. A hot-stamping aluminum formation process comprising: subjecting an aluminum panel to solutionizing, forming and quenching in a stamping die during a first stage, the first stage performed for a first time period and including a second time period of about 2-6 minutes when the aluminum panel is subjected to a temperature of about 540-550 degrees Celsius, the first stage also including in-die quenching of the aluminum panel after the second time period; and subjecting the aluminum panel to pre-aging during a second stage after the first stage, the second stage including a third time period of about 30-60 minutes when the aluminum panel is subjected to a temperature of about 200-210 degrees Celsius.

2. The hot-stamping aluminum formation process of claim 1, wherein the first stage and the second stage form a stamped panel for an energy absorption side structure for a vehicle, the stamped panel having a series of ridges each extending substantially perpendicular to a longitudinal axis of the stamped panel.

3. The hot-stamping aluminum formation process of claim 1, wherein the aluminum panel includes: about 0.40-1.00% Mn, about 0.0-0.50% Fe, about 0.60-1.20% Mg, about 0.70-1.30% Si, about 0.0-0.10% Cu, about 0.0-0.20% Zn, about 0.0-0.10% Ti, about 0.0-0.25% Cr, about 0.0-0.15% residual material(s), and a balance of aluminum.

4. The hot-stamping aluminum formation process of claim 1, wherein the first time period is about 12 minutes.

5. The hot-stamping aluminum formation process of claim 1, wherein the second time period is about 3-5 minutes.

6. The hot-stamping aluminum formation process of claim 5, wherein the second time period is about 4 minutes.

7. The hot-stamping aluminum formation process of claim 1, wherein the in-die quenching is performed for a fourth time period shorter than the second time period.

8. The hot-stamping aluminum formation process of claim 1, wherein the first stage further includes a temperature increase stage when the aluminum panel is being heated to the temperature of about 540-550 degrees Celsius, and wherein the in-die quenching is performed for a fourth time period shorter than the temperature increase stage.

9. The hot-stamping aluminum formation process of claim 1, further comprising performing natural aging of the aluminum panel during a third stage directly after the second stage, the natural aging performed with the aluminum panel removed from the die.

10. The hot-stamping aluminum formation process of claim 1, further comprising subjecting the aluminum panel to a holding period between the second time period and the indie quenching.

11. The hot-stamping aluminum formation process of claim 1, wherein the second stage lasts for about 70-80 minutes.

12. The hot-stamping aluminum formation process of claim 11, wherein the second stage lasts for about 75 minutes.

13. The hot-stamping aluminum formation process of claim 1, further comprising performing painting and baking of the aluminum panel after the second stage.

14. The hot-stamping aluminum formation process of claim 13, further comprising assembling the aluminum panel with another aluminum panel after the second stage and before performing the painting and baking.

15. The hot-stamping aluminum formation process of claim 1, wherein the third time period is about 40-50 minutes.

16. The hot-stamping aluminum formation process of claim 15, wherein the third time period is about 45 minutes.