Coated steel, hot-stamped component formed from coated steel, and hot-
By applying an iron-based coating on the Al-Si coating to form an intermetallic layer, the problem of Al-Si coating transferring to the roller is solved, the heating rate is increased, the risk of roller damage is reduced, and more efficient hot stamping production is achieved.
Patent Information
- Application Number
- CN202480016836.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-03-07
- Filing Date
- 2024-03-06
- Publication Date
- 2025-10-21
AI Technical Summary
In the prior art, Al-Si coatings are easily transferred to the rollers during hot stamping, causing damage to the rollers and requiring expensive repairs, and the heating rate is slow.
An iron-based coating is applied on the Al-Si coating to form an intermetallic layer, which prevents the Al-Si coating from transferring to the roller and increases the heating rate.
The damage of the roller is reduced, the heating rate is increased, the repair cost is reduced, and the production efficiency is improved.
Smart Images
Figure CN120826490A_ABST
Abstract
Description
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] This PCT international patent application claims the benefit of and priority to U.S. Provisional Patent Application Serial No. 63 / 450,394, filed on March 7, 2023, entitled “Coated Steel, Hot Stamping Parts Formed Therefrom, And Hot Stamping Method,” the entire disclosure of which is incorporated herein by reference. Background of the Invention 1. Technical Field
[0003] The present invention relates to a coated blank formed from steel, a method for producing a coated steel blank, a component formed from a coated steel blank, and a method for producing a component by hot stamping a coated steel blank. 2. Background Technology
[0004] This section provides background information related to the present disclosure which is not necessarily prior art.
[0005] Ultra-high-strength components formed from steel are often desired for use in vehicles. Ultra-high-strength steel components are typically formed from a blank of a steel alloy. Methods for manufacturing the component may include hot stamping the blank to achieve the desired shape. The hot stamping process typically involves heating the blank in a furnace to a temperature in the range of 880°C to 950°C and then transferring the heated blank to a die in a stamping press. The hot stamping process also includes forming and quenching the blank in the die to form the component.
[0006] The heating step of the hot stamping process typically involves heating the blank in a roller-hearth furnace. The roller-hearth furnace includes rollers, such as those formed from ceramic, that transport the blank from the furnace entrance to the furnace exit while the blank is being heated. Typically, the steel blank is coated with a material formed from aluminum and silicon, known as an Al-Si coating. The Al-Si coating is typically used to prevent oxidation and decarburization of the blank in the furnace. During the heating process, the Al-Si coating reacts with the iron from the base steel to form an intermetallic layer that provides corrosion protection. However, at least a portion of the Al-Si coating undergoes an intermediate transition to a liquid phase during the heating process, and it has been found that the liquid may transfer to the rollers of the roller-hearth furnace, which may cause the rollers to break and require expensive repairs. Therefore, a technology that avoids or reduces the need for such expensive repairs is desired. Summary of the Invention
[0007] This section provides a general summary of the disclosure and is not to be construed as a complete and comprehensive listing of all objects, aspects, features, and advantages associated with the disclosure.
[0008] One aspect of the subject disclosure provides a blank formed of steel coated with a material formed of aluminum and silicon (Al-Si coating). The blank also includes a coating formed of an iron-based material (iron-based coating) disposed on the Al-Si coating.
[0009] Another aspect of the present disclosure includes a method of making a blank formed of steel. The method includes applying an Al-Si coating to the steel and then applying an iron-based coating to the Al-Si coating.
[0010] Another aspect of the present disclosure provides a component formed from steel. The component includes an Al-Si coating disposed on the steel and an iron-based coating disposed on the Al-Si coating. The finished component typically includes an intermetallic layer formed from the Al-Si coating, the iron-based coating, and the iron from the steel.
[0011] Yet another aspect of the present disclosure provides a method of manufacturing a component formed of steel, the method comprising hot stamping a blank formed of steel, wherein the blank comprises an Al—Si coating disposed on the steel and an iron-based coating disposed on the Al—Si coating.
[0012] Further areas of applicability will become apparent from the description provided herein.The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The drawings described herein are for illustrative purposes only of selected embodiments and are not intended to limit the scope of the present disclosure. The inventive concepts associated with the present disclosure will be more readily understood by reference to the following description taken in conjunction with the accompanying drawings, in which:
[0014] Figure 1 illustrates a hot stamping process including a roller hearth furnace for producing components from steel blanks according to example embodiments;
[0015] Figure 2 Examples include damaged ceramic rollers from roller-hearth furnaces;
[0016] Figure 3 illustrates a heating step of a hot stamping process according to example and comparative embodiments; and
[0017] Figure 4 A component, specifically a B-pillar, is formed by a hot stamping process according to an example embodiment. DETAILED DESCRIPTION
[0018] Example embodiments will now be described more fully with reference to the accompanying drawings. However, only example embodiments are provided so that the present disclosure will be thorough and will fully convey the scope to those skilled in the art. Many specific details such as examples of specific components, devices and methods are set forth to provide a thorough understanding of the embodiments of the present disclosure. It will be clear to those skilled in the art that specific details need not be adopted and that the example embodiments can be implemented in many different forms and none of them should be construed as limiting the scope of the present disclosure. In some example embodiments, well-known processes, well-known device structures and well-known technologies are not described in detail.
[0019] One aspect of the subject disclosure provides a method for manufacturing a component 10 for a vehicle, and specifically an ultra-high strength steel component 10. The component 10 can be designed to be used as a body structure of a vehicle, such as an A-pillar, an A-pillar reinforcement, a side member, a B-pillar, a B-pillar reinforcement, a hinge pillar, a roof rail, a roof header, a roof bow, a door knocker, a double door knocker, a front rail, a rear rail, a side reinforcement, a rocker beam, a rocker panel, an upper firewall, a lower firewall, a firewall reinforcement, a tunnel, and a tunnel reinforcement. The component 10 can also be designed for use in a battery electric vehicle (BEV) or an electric vehicle (EV), such as a battery tray side member, a battery tray cross member, a battery tray reinforcement, a corner reinforcement, a battery tray cover, and a battery tray cover reinforcement.
[0020] The method begins by making or obtaining a blank 12 formed of steel, such as 22MnB5 steel or another steel alloy. The blank 12 is in the form of a sheet and typically has a thickness in the range of 0.5 mm to 3 mm.
[0021] The method then includes coating the blank 12 with a material formed from aluminum (Al) and silicon (Si), referred to as an Al-Si coating 14. More specifically, the Al-Si coating 14 is primarily a heterogeneous mixture of elemental aluminum and elemental silicon. Based on the total weight of the Al-Si coating 14, the Al-Si coating 14 typically includes aluminum in an amount of 85% to 95% by weight and silicon in an amount of 5% to 15% by weight, for example, 90% by weight aluminum and 10% by weight silicon. The Al-Si coating 14 typically has a thickness in the range of 1 to 100 microns or 15 to 30 microns.
[0022] The method next includes applying a coating formed of an iron-based material, referred to as an iron-based coating 16, to the Al-Si coating 14. The iron-based coating 16 is preferably rich in iron and may be formed entirely of iron or may be formed of an iron-containing compound, such as Fe2O3. The iron-based coating 16 typically comprises at least 90% by weight iron, based on the total weight of the iron-based coating 16. The iron-based coating 16 typically has a thickness in the range of 0.1 mm to 300 mm.
[0023] The method then includes hot stamping the coated blank 12. This step involves heating the coated blank 12 in a furnace, such as a roller hearth furnace 18. In the roller hearth furnace 18, the blank 12 is conveyed from the entrance of the furnace 18 to the exit of the furnace 18 along rollers 20 formed of ceramic. The blank 12 is typically heated to a temperature in the range of 840° C. to 950° C. The heating time is typically in the range of 5 minutes to 8 minutes.
[0024] During the heating step, iron from the steel blank 12 typically diffuses into the Al-Si coating 14 and forms an intermetallic layer 26. The intermetallic layer 26 may include Al2FeSi, Al3FeSi2, Al7Fe2Si, Al 4.5 FeSi, Al3Fe and Al5Fe2.
[0025] Furthermore, during the heating step, the Al-Si coating 14, when used without the iron-based coating 16, typically melts into a semi-liquid state and transfers to the ceramic roller 20 in the furnace 18. However, when the iron-based coating 16 is applied to the Al-Si coating 14, iron from the iron-based coating 16 diffuses into the Al-Si coating 14 and prevents the Al-Si coating 14 from transferring to the roller 20.
[0026] More specifically, during the heating step, iron from the iron-based coating 16 diffuses into the Al-Si coating 14 and contributes to the intermetallic layer 26. The presence of the iron-based coating 16 reduces the amount of time the Al-Si coating 14 spends in a semi-liquid state, during which there is a high risk of roll contamination, which occurs before complete iron diffusion and resolidification of the Al-Si coating 14. The intermetallic layer 26 may include Al2FeSi, Al3FeSi2, Al7Fe2Si, Al 4.5 FeSi, Al3Fe and Al5Fe2.
[0027] The iron-based coating 16 also increases the absorption properties and improves the overall heating rate of the blank 12. Therefore, the blank 12 including the Al-Si coating 14 applied to the iron-based coating 16 may require less time to reach the temperature required for hot stamping than a blank including the Al-Si coating without the iron-based coating. Figure 3 The heating step according to the example embodiment in which the blank 12 includes the Al-Si coating 14 and the iron-based coating 16 and the heating step according to the comparative embodiment in which the blank includes only the Al-Si coating are illustrated. Figure 3 As shown in FIG, at the end of the heating process, the blank 12 includes an intermetallic layer 26 on the steel.
[0028] After the heating step, the hot stamping process includes transferring the heated and coated blank 12 to the die of a hot stamping press 24. When the forming process begins, the coated blank 12 is typically at a temperature in the range of 500°C to 930°C. The coated blank 12 is then formed and quenched in the die of the hot stamping press 24 to form the component 10. During this step, the blank 12 can be formed into the shape required for use in a vehicle. Figure 4 An example of a thermoformed component 10 is shown in FIG. In this example, the thermoformed component 10 is a B-pillar.
[0029] It should be understood that the foregoing description of the embodiments has been provided for illustrative purposes. In other words, this subject disclosure is not intended to be exhaustive or limit the present disclosure. Each element or feature of a particular embodiment is generally not limited to that particular embodiment, but is interchangeable where applicable and can be used in a selected embodiment, even if not specifically shown or described. Each element or feature of a particular embodiment also can be changed in many ways. These variations should not be considered as departing from the present disclosure, and all such modifications are intended to be included within the scope of the present disclosure.
Claims
1. A blank comprising: Sheets made of steel; An Al-Si coating provided on the sheet made of steel; as well as An iron-based coating is provided on the Al-Si coating.
2. The blank according to claim 1, wherein The steel is 22MnB5 steel.
3. The blank according to claim 1, wherein The blank is formed from 22MnB5 steel and has a thickness in the range of 0.5 mm to 3 mm; The Al-Si coating is a heterogeneous mixture of elemental aluminum and elemental silicon; The Al—Si coating layer includes aluminum in an amount of 85 wt % to 95 wt % and silicon in an amount of 5 wt % to 15 wt % based on the total weight of the Al—Si coating layer; The Al-Si coating has a thickness in a range of 15 micrometers to 30 micrometers; The iron-based coating is entirely formed of iron or Fe2O3; The iron-based coating comprises at least 90 wt. % iron, based on the total weight of the iron-based coating; and The iron-based coating has a thickness in the range of 0.1 mm to 300 mm.
4. A method for manufacturing the blank according to claim 1, comprising the steps of: applying the Al—Si coating to the sheet made of steel, and The iron-based coating is applied to the Al-Si coating.
5. The method according to claim 4, wherein The heating step includes heating the coated blank in a roller hearth furnace.
6. The method according to claim 5, wherein: The heating step includes conveying the coated blank from an inlet of the roller hearth furnace along rollers formed of ceramic to an outlet of the roller hearth furnace.
7. A component comprising: Sheets made of steel; as well as An intermetallic layer is formed by the Al—Si coating, the iron-based coating, and the iron from the sheet made of steel.
8. The component according to claim 7, wherein The intermetallic compound layer includes intermetallic compounds, and the intermetallic compounds include Al2FeSi, Al3FeSi2, Al7Fe2Si, Al 4.5 At least one of FeSi, Al3Fe and Al5Fe2.
9. The component according to claim 7, wherein The component is an A-pillar, an A-pillar reinforcement, a side member, a B-pillar, a B-pillar reinforcement, a hinge pillar, a roof rail, a roof header, a roof bow, a door knocker, a double door knocker, a front rail, a rear rail, a side reinforcement, a rocker beam, a rocker panel, an upper firewall, a lower firewall, a firewall reinforcement, a tunnel or a tunnel reinforcement.
10. The component according to claim 7, wherein The component is a battery tray side member, a battery tray cross member, a battery tray reinforcement, a corner reinforcement, a battery tray cover, or a battery tray cover reinforcement.
11. The component according to claim 7, wherein The component is a B-pillar.
12. A method of manufacturing a component, the method comprising: applying an Al-Si coating to a blank formed of steel, applying an iron-based coating to the Al-Si coating, heating the coated blank, and After heating the coated blank, the coated blank is shaped.
13. The method according to claim 12, wherein: The heating step includes heating the coated blank in a roller hearth furnace.
14. The method according to claim 12, wherein: The heating step includes conveying the coated blank from an inlet of the roller hearth furnace along rollers formed of ceramic to an outlet of the roller hearth furnace.
15. The method according to claim 12, wherein: The blank is formed of 22MnB5 steel; The blank has a thickness in the range of 0.5 mm to 3 mm; The Al-Si coating is a heterogeneous mixture of elemental aluminum and elemental silicon; The Al—Si coating layer includes aluminum in an amount of 85 wt % to 95 wt % and silicon in an amount of 5 wt % to 15 wt % based on the total weight of the Al—Si coating layer; The Al-Si coating has a thickness in a range of 15 micrometers to 30 micrometers; The iron-based coating is entirely formed of iron or Fe2O3; The iron-based coating comprises at least 90 wt. % iron based on the total weight of the iron-based coating; The iron-based coating has a thickness in the range of 0.1 mm to 300 mm; The step of heating the coated blank includes heating the coated blank in a roller hearth furnace; The step of heating the coated blank in the roller hearth furnace comprises conveying the coated blank from an inlet of the furnace to an outlet of the furnace along rollers formed of ceramic; The step of heating the coated blank includes heating the coated blank to a temperature in the range of 840° C. to 950° C. for 5 minutes to 8 minutes; wherein during the heating step, the iron from the iron-based coating diffuses into the Al-Si coating and prevents the Al-Si coating from transferring to the roller; During the heating step, a layer of intermetallic compounds is formed in the blank, and the intermetallic compounds include Al2FeSi, Al3FeSi2, Al7Fe2Si, Al 4.5 At least one of FeSi, Al3Fe, and Al5Fe2; The forming steps include hot stamping; The hot stamping step includes transferring the heated and coated blank to a die of a hot stamping press; The hot stamping step includes stamping the coated blank while the coated blank is at a temperature in the range of 500° C. to 930° C.; and The hot stamping step includes quenching the blank in the die after the stamping step.