The present invention relates to a process for forming components such as stamped parts and stamped bent parts and more particularly to a process for forming stamped parts that have desired geometries with strengthened regions corresponding to expected loads.
Components such as automotive components and particularly automotive seat structure components are advantageously formed of one or more shaped parts such as stamped parts. The sheet metal from which the part is to be made is stamped in a stamping press using a stamping die (tooling). Particularly, sheet blanks are subjected to one or more stamping processes to form stamped parts. One or more stamped parts are used to form an automotive structure or component. Based on the expected loads, the parts may be required to be formed as complex geometric shapes with complex sections and multiple parts that must be joined.
Heat treatments are known for changing the characteristics of metal parts. However, with stamping processes it is difficult to selectively apply heat treatment to particular areas of a formed automotive seat structure or component during the stamping process.
It is an object of the invention to provide the ability to selectively apply heat treatment to discrete particular areas of a formed automotive seat structure or component for load management.
According to the invention, a component formation process is provided comprising the steps of providing a steel blank, preliminarily stamping the steel blank using a stamping press to form a preliminarily stamped intermediate component and laser hardening the preliminarily stamped intermediate component in selected regions of the preliminarily stamped component. The laser hardening is followed by either further preliminarily stamping, further laser hardening or a final stamping to form a stamped component. The stamped component is ejected from the stamping press as a stamped component with selectively hardened regions and non-hardened regions.
The laser hardening may advantageously be provided by directing a laser beam at the preliminarily stamped intermediate component at a laser hardening station that is a separate station from the stamping press. The step of stamping the preliminarily stamped intermediate component to form a stamped component, may be carried out in a stamping press that is different from the stamping press used for preliminarily stamping the steel blank.
The laser hardening may advantageously be provided by directing a laser beam at the preliminarily stamped intermediate component with a laser output in or supported adjacent to a tool of the stamping press. The stamping press may also comprise additional laser outlets in the tool of the stamping press, the laser outlets being supplied with a radiation source from one or more lasers.
The heating and cooling may be regulated as to location, duration and degree. The power of the laser may be varied and moved and sized as needed. Cooling techniques may be used to change the rate and set the duration of cooling. A quenching operation may follow laser hardening or may follow stamping. Subsequent to the step of laser hardening the preliminarily stamped intermediate component may advantageously be subjected to an oil quenching operation. The oil quenching operation may advantageously comprise selectively applying quenching oil to the regions of the component that were subjected to the laser hardening.
The step of stamping the preliminarily stamped intermediate component, to form a stamped component, may advantageously be followed by quenching with the stamped component in a die of the stamping press. Particularly, an in die quenching operation may be used.
According to another aspect of the invention, a component is formed according to the method of the invention. The component has predefined hardened areas and predefined areas that have not been hardened. The component is particularly an automotive component formed by the process according to the invention.
The process is used to provide a stamped component that is one of an automotive seat recliner side member, an automotive seat recliner B bracket, an automotive seat track rail; and RR structural components, recliner and tracks components.
The selectively hardened regions may advantageously be at or adjacent to bend portions, openings and regions to be subjected to greater loads than adjacent non-hardened regions with the selectively hardened regions defining a predetermined load path.
The formation of particular geometries, including bend portions, curved portions, flanges, teeth, edge borders and openings may be facilitated by a laser formability process, wherein at least one of the steel blank and the preliminarily stamped intermediate component is subjected to a laser heating to change a formability of the at least one of the steel blank and the preliminarily stamped intermediate component. The laser beam may advantageously be directed at selective regions of the at least one of the steel blank and the preliminarily stamped intermediate component to soften the selected region prior to a subsequent stamping of the at least one of the steel blank and the preliminarily stamped intermediate component. In particular, prior to at least one of the step of preliminarily stamping the steel blank and stamping the preliminarily stamped intermediate component, a laser beam is directed at a selected region of at least one of the steel blank and the preliminarily stamped intermediate component to soften the selected region of the at least one of the steel blank and the preliminarily stamped intermediate component. The selected region of the at least one of the steel blank, and the preliminarily stamped intermediate component is softened.
The laser hardening may be a plurality of laser hardening steps the laser hardening steps may each be followed by one of a plurality of stamping steps. A plurality of laser softening steps may each precede one of a plurality of stamping steps.
The invention allows for the mass of the component to be lowered and allows the performance of a vehicle seat structure or vehicle components to be improved by selectively heat treating sections for load management. The invention provides selected laser-hardened regions and adjacent non-hardened regions. Characteristics of the non-hardened regions remain unchanged whereas the laser-hardened regions are relatively strengthened. The invention replaces conventional methods of load management that use complex geometric shapes & sections.
According to another aspect of the invention, a stamped steel or steel alloy structural component is provided comprising one or more edges and at least one of a bend portion with a selectively laser-hardened region at or adjacent to the bend portion an opening passing through the stamped steel structural component with a selectively laser-hardened region at or adjacent to the opening and a load path region with selectively laser-hardened region at or adjacent to the load path region, the laser-hardened region defining a predetermined load path in the load path region. The laser-hardened region is advantageously adjacent to at least one region that has not been subjected to laser hardening.
Regions adjacent to the selectively laser-hardened region define one or more deformation zones which deform in a predetermined manner upon being subjected to a predetermined load. The load path regions may be at the laser-hardened region and advantageously extend between support locations of the component. The defined load paths have regions that have been hardened and regions that retain the material characteristics.
The invention is particularly advantageous as to automotive parts, and particularly automotive vehicle seat components. Automotive seat structures or components are provided according to the invention that exhibit predictable and repeatable load path performance with improved part geometry. Automotive seat structures or components are provided according to the invention with a 30% mass decrease and cost decrease from a conventional design. This mass and cost decrease allows for a conservation of structural and/or functional requirements.
According to the invention, automotive seat structures or components may be created and designed as a monolithic component with multiple phase microstructures and mechanical properties. The seat structure parts may have defined hardened regions and defined regions that still have the original strength/hardness characteristics of the material. Further, the stamping of the part may be facilitated by selectively heating regions of the blank or the preliminarily stamped intermediate component.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
Referring to the drawings,
Step 1 involves providing a steel blank 10 and inserting the steel blank 10 into a stamping press 14 using a stamping die (tooling) 16. The stamping press 14 may be a conventional stamping press. In the alternative, the stamping press may be a stamping press 14′ including one or more laser outlets 20, for laser hardening, with the laser outlet 20 provided in the stamping press 14′ and/or tool, such as in a protective recess of the tool 16. The laser outlet 20 may also be attached to the stamping press 14′, or may be attached adjacent to the tool 16 and may be moved into and out of position for use, or may be moved through a use area. If the stamping press 14 is used for step 1, the process uses two different stamping presses 14, 14′ or removes the preliminarily stamped component from the stamping press 14 for laser hardening and then returns it to the stamping press 14. In the alternative, if the stamping press 14′ is used including a laser outlet 20, for laser hardening, that is provided in, at or adjacent to the tool 16, the process may instead be executed wherein the stamped component may be fully processed within the stamping press 14′ with the laser outlet 20.
At step 2, the stamping press 14/14′ provides a preliminary stamping. This forms a preliminarily stamped intermediate component 22. The preliminary stamping 2 forms the shape/geometry of selected regions—regions which are to be selectively hardened. The preliminarily stamped intermediate component 22 is then subjected to laser hardening via step 3. According to one variation of the process of the invention, the preliminarily stamped intermediate component is removed from the stamping press after stamping—step 2—and is moved to a separate station for laser hardening—step 3. With this, the selected regions are subjected to the heat of the laser treatment to provide a selective hardening of these particular selected regions. Other regions of the preliminarily stamped intermediate component are not subjected to the laser hardening. This provides a selective hardening of portions of the preliminarily stamped intermediate component. Advantageously, the portions which have been hardened have already been stamped, to fully or essentially provide a final shape/geometry.
As an alternative, the laser hardening of step 3′ is provided with the preliminarily stamped intermediate component 22 still in the stamping press. With the laser hardening of step 3′, the stamping press is a stamping press 14′ including one or more laser outlets 20, for laser hardening in, at, or adjacent to the tool 16. The laser hardening may be conducted without moving the preliminarily stamped intermediate component 22 from the stamping press. The stamping press 14′, including a laser outlet 20, may include a plurality of laser outlets, to provide laser hardening at numerous different selected regions. The laser outlets may be supplied by one or more lasers 23 (via optical fibers). With this, the selected regions are subjected to the heat of the laser treatment to provide a selective hardening of these particular selected regions. Other regions of the preliminarily stamped intermediate component are not subjected to the laser hardening. This provides a selective hardening of portions of the preliminarily stamped intermediate component. Advantageously, the portions which have been hardened have already been stamped, to fully or essentially provide a final shape/geometry.
The steps 3 or 3′ may be followed by an optional oil quenching operation 3a. The oil quenching operation 3a includes selectively applying quenches (quenching media), in particular oil 25 to selected locations, to further affect the hardness attributes (material attributes) of the preliminarily stamped intermediate component. The oil quenching operation 3a may provide a specific and directed quenching of specific regions or may subject the overall preliminarily stamped intermediate component to oil quenching at a rate and for a duration. Other quenches may be used including air, oil and in die quenching 24 as shown in
The process then proceeds to subsequent preliminary stamping operations (and further laser hardening operations) or to the final stamping step 4. This final stamping 4 can impart the final shape of a stamped component. Advantageously, the stamping includes an in-die quenching, whereby heat generated during stamping is quickly dissipated to provide better characteristics for the final stamped component. Subsequently, the component part 18 is ejected at step 5, with the component part 18 having selected regions which are hardened and also having other regions which have not been subjected to the laser hardening.
The automotive stamped steel structural component of the invention comprises one or more selectively laser-hardened regions and regions that are not laser-hardened. The selection of the regions and the selective application of the laser hardening advantageously may include a methodology in which regions are chosen to manage load paths and to strengthen known regions which require strengthening, such as regions adjacent to openings, narrow edge regions (such as teeth flanges), edge borders, curved and bent portions and similar known areas which require strength due to the geometry and the expected load. Additionally, load paths may be managed to provide predictable and repeatable responses of the component to defined loads. The regions may be selected to provide predetermined deformation (bending/buckling) under directed loads related to a vehicle crash. Load paths may even be directed to cause particular failure or to channel directed loads in selected directions, such as strengthened portions or assemblies of the vehicle seat or vehicle structure.
The laser hardening may be following one or a series of stamping steps and may be provided in combination with subsequent laser hardening steps to selectively stamp and harden particular regions of the preliminarily stamped intermediate component. This may be combined with a selective laser softening, by heating selective regions, in combination with one or a series of stamping steps. In particular, with regard to step 3, laser hardening may be provided in combination with laser softening wherein the laser softening allows for a deeper drawing and results in better geometries or more complex geometries upon being subjected to the next stamping step.
The power of the laser, the region of laser application, and other laser parameters may be selected along with a selection of the cooling and timing of the heat application, stamping and quenching. The selection of laser parameters, such as power, and the selection of other parameters are considered based on the properties of metal, for example, the properties of the metal relative to heating and quenching rates may be considered with regard to selecting the parameters to provide the eventual product having the desired characteristics. The selection of various parameters is considered in combination with a selection of the region of the steel blank, based on the final geometry and/or preliminarily stamped intermediate component, to provide the softening (for formability) and hardening as needed. The selection of regions for softening and hardening and quenching provides special and particular geometries as well as providing a resulting part with predetermined regions of hardness as well as other qualities (for example buckle zones or the like for defined deformation during an automotive crash or the like). In particular, according to the invention, not all of the final component needs to be subjected to the laser heating treatment. Some of the part may be heated for improved formability, just prior to a stamping stage. Other parts may be subjected to laser heating to harden the part as described. These laser heating steps are combined with stamping steps in which each stage provides a different form based on the stamping (and the tool provided) to achieve the final product.
The selective hardening provides the ability to define load paths in the final product. The designer may direct loads for normal use and also direct loads with regard to a crash situation or the like. Buckle areas (defined deformation regions under predetermined loads) may be defined such that the final part provides a defined buckling or deformation based on particular load situations. By selectively hardening some regions prior to or following stamping, the final product (component) may be provided with repeatable and reliable crumple or buckle regions that allow for a repeatable and reliable deformation of the part, during defined load situations.
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The selective laser heat treatment allows for a selective hardening to provide local hardened regions and to also maintain regions with the original characteristics of the base metal. The base material properties may be selectively altered or retained to change the strength and hardness and to selectively direct the load to provide predefined load paths. The load paths may be formed based on strengthened areas and adjacent areas that may be potential buckle areas.
While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.
This application is a United States National Phase Application of International Application PCT/US2015/032150 filed May 22, 2015 and claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application U.S. 62/002,270 filed May 23, 2014, the entire contents of which are incorporated herein by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/US15/32150 | 5/22/2015 | WO | 00 |
Number | Date | Country | |
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62002270 | May 2014 | US |