EP3181716A1 - Robust crash durable adhesive bonding of boron steel - Google Patents
Robust crash durable adhesive bonding of boron steel Download PDFInfo
- Publication number
- EP3181716A1 EP3181716A1 EP15200622.7A EP15200622A EP3181716A1 EP 3181716 A1 EP3181716 A1 EP 3181716A1 EP 15200622 A EP15200622 A EP 15200622A EP 3181716 A1 EP3181716 A1 EP 3181716A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- adhesive
- component
- steel
- boron steel
- coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 229910000712 Boron steel Inorganic materials 0.000 title claims abstract description 74
- 238000004026 adhesive bonding Methods 0.000 title 1
- 239000000853 adhesive Substances 0.000 claims abstract description 66
- 230000001070 adhesive effect Effects 0.000 claims abstract description 66
- 238000000576 coating method Methods 0.000 claims abstract description 58
- 239000011248 coating agent Substances 0.000 claims abstract description 57
- 238000000034 method Methods 0.000 claims abstract description 38
- KMWBBMXGHHLDKL-UHFFFAOYSA-N [AlH3].[Si] Chemical compound [AlH3].[Si] KMWBBMXGHHLDKL-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229910000831 Steel Inorganic materials 0.000 claims description 28
- 239000010959 steel Substances 0.000 claims description 28
- 238000003466 welding Methods 0.000 claims description 9
- 239000004411 aluminium Substances 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- 239000010953 base metal Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000004593 Epoxy Substances 0.000 description 3
- 230000032798 delamination Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 229910000734 martensite Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 229910001335 Galvanized steel Inorganic materials 0.000 description 1
- 102100026964 M1-specific T cell receptor beta chain Human genes 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000008397 galvanized steel Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000009863 impact test Methods 0.000 description 1
- 230000016507 interphase Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 239000004848 polyfunctional curative Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000011076 safety test Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/12—Aluminium or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/26—After-treatment
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
- C22C21/02—Alloys based on aluminium with silicon as the next major constituent
Definitions
- the present invention concerns a method for selectively removing at least part of an Aluminium-Silicon (Al-Si) coating from Al-Si-coated Boron steel.
- Al-Si Aluminium-Silicon
- the present invention also concerns a method for bonding Al-Si-coated Boron steel to another component.
- Hot press forming of Boron steel is being increasingly used in automotive industries due to Boron steel's high tensile strength and minimal spring back.
- the use of Boron steel can namely result in a weight reduction of vehicle body parts and improvements in vehicle safety and fuel efficiency.
- High-strength Boron steel sheets are often coated with an Al-Si layer in order to prevent oxidation, corrosion and scaling of components during hot press forming, and this can increase the components' reliability with a view to dimensional accuracy and stress distribution when they are in service.
- the Al-Si coating adversely affects the strength of bonds that are formed when Al-Si-coated Boron steel is welded or adhered to another component.
- the Al-Si metallic surface layer does not namely form a strong metallic bond to the underlying base metal. It is known that the Al-Si coating tends to delaminate in from the base metal along adhesive bond lines during bond line failure under static or dynamic loading (for example in crash and durability tests). The delamination may occur at the base metal, or close to the base metal.
- An object of the present invention is to provide an improved method for selectively removing at least part of an Al-Si coating from Al-Si-coated Boron steel.
- the method comprises the steps of bonding an offer strip to the Al-Si-coated Boron steel using an adhesive, and curing the adhesive, whereby the adhesive adheres to the Al-Si coating, and subjecting the offer strip to a peel and/or shear force, for example by peeling and/or shearing off the offer steel strip from the Al-Si-coated Boron steel to which it has been bonded, to mechanically remove at least part of the Al-Si coating from the Al-Si-coated Boron steel.
- the Al-Si coating is removed as the offer strip is peeled and/or sheared off because the bond formed between the Al-Si coating and the adhesive is stronger than the bond formed between the Al-Si coating and the Boron steel.
- All, or at least part of the Al-Si coating on at least one part of an Al-Si-coated Boron steel surface may therefore be removed in order to provide at least one uncoated point/line/area, i.e. at least one region of any desired shape or size from which all or some of the Al-Si coating has been removed, which may for example subsequently be used as a bond point/line/area to which another component may be bonded.
- a bond formed in the at least one uncoated point/line/area will be stronger than a bond formed on part of the Al-Si-coated Boron steel from which the Al-Si coating has not been removed due to the lack of an Al-Si coating in that at least one uncoated point/line/area, or due to the reduced amount of Al-Si in that at least one uncoated or less coated part.
- a reduced amount of Al-Si coating is intended to mean a reduced amount of Al-Si as regards the area over which the Al-Si coating is spread, and/or the thickness of the Al-Si coating.
- a crash durable adhesive may subsequently be applied to the at least one uncoated part and cured, whereby a robust, durable and crash durable adhesive bond may be provided.
- the risk of bond failure due to the delamination of an Al-Si coating from Al-SI-coated Boron steel is eliminated or reduced using a method according to the present invention.
- the resulting cohesive bond line failure mode allows for Computer-aided engineering (CAE) modelling of the bond line based on cohesive zone models.
- CAE Computer-aided engineering
- offer strip as used in this document is intended to mean any sacrificial component of any suitable size, shape, thickness and material, such as a relatively thin, long, narrow piece of material, which is arranged to be temporarily bonded to at least part of the surface of Al-Si-coated Boron steel and subsequently removed so that the adhesive and the Al-Si coating to which that adhesive has adhered is also removed with the offer strip.
- Boron steel components are manufactured with a knowledge of where they are to be bonded to at least one other component. A skilled person will therefore be able to provide a suitable offer strip for use with a particular component in order to remove at least part of an Al-Si from a particular part or parts of that component.
- One offer strip may be used to remove the Al-Si coating from one or a plurality of parts of a Boron steel component. Alternatively, a plurality of offer strips may be used to remove the Al-Si coating from a single part of a Boron steel component.
- curing the adhesive is intended to mean any physical and/or chemical process that is required to cause an adhesive to form a bond between the surfaces between which it is applied.
- some adhesives require a chemical reaction, such as but not limited to crosslinking, to convert them from a liquid (or thermoplastic polymer) to solid (or thermoset polymer). Once cured, these adhesives provide high strength, flexible to rigid bonds that resist temperature, humidity, and many chemicals.
- Some adhesives require either high temperature or substances or media (light, humidity, radiation) from the surroundings to initiate the curing mechanism and activate their hardener.
- the expression "whereby the adhesive adheres to the Al-Si coating” is intended to mean that the adhesive forms a bond with the Al-Si coating so that once the offer strip is subjected to a peel and/or shear force, then at least part of the Al-Si coating to which the adhesive is bonded will come away from the base metal (the Boron steel) to which it is also bonded.
- the adhesive comprises a crash-durable structural adhesive or a high strength structural adhesive.
- the adhesive may be an epoxy-based adhesive.
- the offer strip comprises one of the following: steel, a high strength steel, an uncoated or hot-dip galvanized coated steel.
- the present invention also concerns a method for bonding Al-Si-coated Boron steel to another component, which comprises the steps of the method for selectively removing at least part of an Al-Si coating from Al-Si-coated Boron steel according to any embodiment of the present invention.
- the method for bonding Al-Si-coated Boron steel to another component namely comprises the steps of bonding an offer strip to the Al-Si-coated Boron steel using an adhesive, curing the adhesive, whereby the adhesive adheres to the Al-Si coating, and subjecting the offer strip to a peel and/or shear force to mechanically remove at least part of the Al-Si coating from the Al-Si-coated Boron steel and thereby provide at least one uncoated point/line/area on the Al-Si-coated Boron steel, and then bonding the component to the at least one uncoated point/line/area.
- the adhesive comprises a crash-durable structural adhesive or a high strength structural adhesive.
- the component is bonded to the at least one uncoated point/line/area by means of adhesion.
- the adhesive is also used to bond the component to the at least one uncoated point/line/area, i.e. either the same adhesive is used to provide the final permanent bond between the uncoated Boron steel and the component and the temporary bond between the offer strip and the Al-Si-coated Boron steel, or different adhesives are used for each of these bonds.
- the component is bonded to the at least one uncoated point/line/area by means of welding, such as by resistance spot welding, laser welding, arc welding, or any other bonding method.
- the offer strip comprises one of the following: steel, a high strength steel, an uncoated or hot-dip galvanized coated steel.
- the component at least one of the following: a vehicle component, such as a vehicle pillar, a tailor roller blank (TRB), a steel component, such as a component comprising coated or uncoated automotive grade steel or a component comprising coated or uncoated automotive grade Boron steel, an aluminium component, such as a component comprising automotive grade aluminium.
- a vehicle component such as a vehicle pillar, a tailor roller blank (TRB)
- a steel component such as a component comprising coated or uncoated automotive grade steel or a component comprising coated or uncoated automotive grade Boron steel
- an aluminium component such as a component comprising automotive grade aluminium.
- the Al-Si-coated steel and/or the component that is attached thereto may comprise hardened Boron steel, which comprises martensitic material, having a tensile strength of 1300 MPa or more.
- the present invention further concerns the use of a coating-removal and/or bonding method according to any of the embodiments of the invention to provide Al-Si-coated (preferably automotive-grade) Boron steel with at least one robust, durable and crash durable bond.
- Figure 1a shows Boron steel 10, having a surface comprising an Aluminium-Silicon (Al-Si) coating 11.
- the Boron steel may constitute at least part of a Boron steel component of any size and shape. Any known manufacturing method may be used to produce and coat such a Boron steel component.
- a component may for example be manufactured by hot forming which involves heating blanks of Boron steel to austenitization temperature in a furnace, for example to a temperature over 900°C, and then quenching and shaping it during controlled cooling processes in order to impart different strengths to different parts of the Boron steel component.
- the Al-Si coating 11 need not necessarily be uniformly applied to the entire surface of Boron steel 10 but can be applied to any part or parts of the surface of Boron steel 10 in any uniform or non-uniform pattern, and/or it may have a uniform or non-uniform thickness as desired.
- the method according to the present invention comprises the step of bonding an offer strip 12 to the Al-Si coating 11 of the Boron steel 10 using an adhesive 13.
- the adhesive 13 may be a crash-durable structural adhesive or a high strength structural adhesive.
- the adhesive 13 is namely applied to one or more parts of the Al-Si coating 11 and/or one or more parts of the offer strip 12 as desired.
- the offer strip 12 may comprise: steel, a high strength steel, an uncoated or hot-dip galvanized coated steel or any other material that is suitable for being bonded to the Al-Si coating 11 of Boron steel 10 and then being peeled and/or sheared off therefrom.
- adhesive 13 is applied to the Al-Si coating 11 and/or the surface of the offer strip 12 in such a way that the entire Al-Si coating of the Al-Si-coated Boron steel 10 will be bonded to the offer strip 12 when the offer strip 12 is joined to the Al-Si-coated Boron steel 10.
- the adhesive 13 is cured in order to form an adhesive bond with the Al-Si coating 11 as shown in figure 1b ).
- the offer strip 12 is subjected to a peel and/or shear force F peel and/or F shear , to mechanically remove at least part of the Al-Si coating 11 from the Al-Si-coated Boron steel 10.
- F peel and/or F shear a peel and/or shear force
- the entire Al-Si coating 11 is mechanically removed from the surface of the Al-Si-coated Boron steel 10.
- the Boron steel 10 will have been provided with at least one uncoated point/line/area 14 as shown in figure 1c ) to which one or more components 15 can be bonded as shown in figure 1d ). It may for example be beneficial in some applications not to remove the entire Al-Si coating 11 so that it can provide some oxidation and/or corrosion protection.
- the component 15 may be bonded to the at least one uncoated point/line/area 14 by means of adhesion, for example using the same adhesive 13, or a different adhesive as that used to temporarily bond the offer strip 12 to the Al-Si coating 11 of the Boron steel 10.
- the component 15 may be bonded to the at least one uncoated point/line/area 1 by means of welding.
- a metallurgical structure analysis may be used to determine that at least part of an Al-Si coating 11 has been removed from Al-Si- coated Boron steel at the uncoated bond point(s)/line(s)/area(s).
- the adhesive or welding bond thus formed will be much more robust, durable and crash durable than if at least part of the Al-Si coating 11 had not been removed prior to the formation of such a bond.
- the component 15 may be a vehicle component, such as a vehicle pillar, a tailor roller blank (TRB), a steel component, such as a component comprising coated or uncoated automotive grade steel or a component comprising coated or uncoated automotive grade Boron steel, an aluminium component, such as a component comprising automotive grade aluminium.
- a vehicle component such as a vehicle pillar, a tailor roller blank (TRB)
- TRB tailor roller blank
- steel component such as a component comprising coated or uncoated automotive grade steel or a component comprising coated or uncoated automotive grade Boron steel
- an aluminium component such as a component comprising automotive grade aluminium.
- Figure 2 shows the region between Boron steel 10 comprising an Al-Si coating 11 and an offer strip 12 that has been bonded thereto by means of an adhesive 13.
- a sorption interphase 16 comprising oil and low molecular weight polymer, oriented fillers etc. may form between the adhesive 13 and the Al-Si coating 11.
- the offer strip 12 may also comprise a surface layer 17, such as an oxide or Zn-layer.
- Figure 3 is a flow diagram showing the steps of a method according to an embodiment of the invention.
- the method comprises the steps of selectively bonding an offer strip 12 to Al-Si-coated Boron steel 10 using an adhesive 13, curing the adhesive 13 and subjecting the offer strip 12 to a peel and/or shear force F peel and/or F shear to mechanically remove at least part of the Al-Si coating 11 from the Boron steel 10 and thereby provide at least one uncoated point, line or area 14 to which one or more components 15 may be bonded.
- Figure 4 shows a vehicle 18 that comprises at least one component that has been subjected to a method according to the present invention during the manufacture of the vehicle 18.
- a vehicle pillar such as an A-pillar 19 or a B-pilllar 20 may comprise Al-Si-coated Boron steel from which at least part of the Al-Si coating has been removed using a method according to the present invention and/or a which has been bonded to another component using a method according to the present invention.
- the A-pillar 19 of the vehicle may comprise at least two component parts that have been bonded together using a method according to the present invention.
- a first upper component part of the A-pillar 19 may comprise automotive grade steel having a tensile strength of 800 MPa or less.
- a second lower part of the A-pillar 19 may comprise hardened Boron steel comprising martensitic material having a tensile strength of 1300 MPa or more.
- the two component parts may be bonded together, for example by means of adhesion or welding, using a method according to the present invention in order to improve the strength and the durability of the bond formed between them.
- the component may constitute a tailor rolled blank (TRB).
- TRB tailor rolled blank
- a TRB or "tailored blank” is a metal sheet, which is typically composed of various steel grades and thicknesses. This allows different parts of a vehicle reinforcement manufactured from the TRB to be adapted to local loads, which would otherwise require additional strengthening components. Benefits of using TRBs therefore include reducing component weight and manufacturing costs.
- individual sheet metal plates are welded together by laser welding to produce a TRB.
- a component comprising Boron steel is stiffer and more lightweight than a corresponding component comprising normal steel on account of the alloys that have been added during manufacture, thereby making a vehicle having at least one such component safer and more fuel-efficient than a vehicle that does not comprise Boron steel components.
- Such a vehicle 18 having such Boron steel components 19, 20 that have been bonded using a method according to the present invention may show improved performance in safety tests and certifying procedures, for example in crash tests, such as side impact tests.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Body Structure For Vehicles (AREA)
Abstract
Description
- The present invention concerns a method for selectively removing at least part of an Aluminium-Silicon (Al-Si) coating from Al-Si-coated Boron steel. The present invention also concerns a method for bonding Al-Si-coated Boron steel to another component.
- Hot press forming of Boron steel is being increasingly used in automotive industries due to Boron steel's high tensile strength and minimal spring back. The use of Boron steel can namely result in a weight reduction of vehicle body parts and improvements in vehicle safety and fuel efficiency. High-strength Boron steel sheets are often coated with an Al-Si layer in order to prevent oxidation, corrosion and scaling of components during hot press forming, and this can increase the components' reliability with a view to dimensional accuracy and stress distribution when they are in service.
- However, the Al-Si coating adversely affects the strength of bonds that are formed when Al-Si-coated Boron steel is welded or adhered to another component. Unlike hot-dip galvanized steel surface coatings, the Al-Si metallic surface layer does not namely form a strong metallic bond to the underlying base metal. It is known that the Al-Si coating tends to delaminate in from the base metal along adhesive bond lines during bond line failure under static or dynamic loading (for example in crash and durability tests). The delamination may occur at the base metal, or close to the base metal.
- Diploma work no. 52/2011 entitled "Adhesively Bonded Steel Structures" by Man-Shin Tan and Nozhan Sharifian, performed at Volvo Car Corporation under the supervision of Johnny K. Larsson, which was published in 2011 focused on the effect of adhesive in the crash performance of High and Ultra High Strength Steels including Usibor™ (Boron steel with an Al-Si coating). The Diploma thesis concluded that epoxy-based adhesive should not be used together with Usibor™ because the delamination of Usibor™'s Al-Si surface coating causes the epoxy-based adhesive to fail.
- An object of the present invention is to provide an improved method for selectively removing at least part of an Al-Si coating from Al-Si-coated Boron steel.
- The method comprises the steps of bonding an offer strip to the Al-Si-coated Boron steel using an adhesive, and curing the adhesive, whereby the adhesive adheres to the Al-Si coating, and subjecting the offer strip to a peel and/or shear force, for example by peeling and/or shearing off the offer steel strip from the Al-Si-coated Boron steel to which it has been bonded, to mechanically remove at least part of the Al-Si coating from the Al-Si-coated Boron steel. The Al-Si coating is removed as the offer strip is peeled and/or sheared off because the bond formed between the Al-Si coating and the adhesive is stronger than the bond formed between the Al-Si coating and the Boron steel.
- All, or at least part of the Al-Si coating on at least one part of an Al-Si-coated Boron steel surface may therefore be removed in order to provide at least one uncoated point/line/area, i.e. at least one region of any desired shape or size from which all or some of the Al-Si coating has been removed, which may for example subsequently be used as a bond point/line/area to which another component may be bonded. A bond formed in the at least one uncoated point/line/area will be stronger than a bond formed on part of the Al-Si-coated Boron steel from which the Al-Si coating has not been removed due to the lack of an Al-Si coating in that at least one uncoated point/line/area, or due to the reduced amount of Al-Si in that at least one uncoated or less coated part. A reduced amount of Al-Si coating is intended to mean a reduced amount of Al-Si as regards the area over which the Al-Si coating is spread, and/or the thickness of the Al-Si coating.
- For example, a crash durable adhesive may subsequently be applied to the at least one uncoated part and cured, whereby a robust, durable and crash durable adhesive bond may be provided. The risk of bond failure due to the delamination of an Al-Si coating from Al-SI-coated Boron steel is eliminated or reduced using a method according to the present invention. The resulting cohesive bond line failure mode allows for Computer-aided engineering (CAE) modelling of the bond line based on cohesive zone models.
- The expression "offer strip" as used in this document is intended to mean any sacrificial component of any suitable size, shape, thickness and material, such as a relatively thin, long, narrow piece of material, which is arranged to be temporarily bonded to at least part of the surface of Al-Si-coated Boron steel and subsequently removed so that the adhesive and the Al-Si coating to which that adhesive has adhered is also removed with the offer strip.
- It should be noted Boron steel components are manufactured with a knowledge of where they are to be bonded to at least one other component. A skilled person will therefore be able to provide a suitable offer strip for use with a particular component in order to remove at least part of an Al-Si from a particular part or parts of that component. One offer strip may be used to remove the Al-Si coating from one or a plurality of parts of a Boron steel component. Alternatively, a plurality of offer strips may be used to remove the Al-Si coating from a single part of a Boron steel component.
- The expression "curing the adhesive" is intended to mean any physical and/or chemical process that is required to cause an adhesive to form a bond between the surfaces between which it is applied. For example, some adhesives require a chemical reaction, such as but not limited to crosslinking, to convert them from a liquid (or thermoplastic polymer) to solid (or thermoset polymer). Once cured, these adhesives provide high strength, flexible to rigid bonds that resist temperature, humidity, and many chemicals. Some adhesives require either high temperature or substances or media (light, humidity, radiation) from the surroundings to initiate the curing mechanism and activate their hardener.
- The expression "whereby the adhesive adheres to the Al-Si coating" is intended to mean that the adhesive forms a bond with the Al-Si coating so that once the offer strip is subjected to a peel and/or shear force, then at least part of the Al-Si coating to which the adhesive is bonded will come away from the base metal (the Boron steel) to which it is also bonded.
- According to an embodiment of the invention the adhesive comprises a crash-durable structural adhesive or a high strength structural adhesive. The adhesive may be an epoxy-based adhesive.
- According to an embodiment of the invention the offer strip comprises one of the following: steel, a high strength steel, an uncoated or hot-dip galvanized coated steel.
- The present invention also concerns a method for bonding Al-Si-coated Boron steel to another component, which comprises the steps of the method for selectively removing at least part of an Al-Si coating from Al-Si-coated Boron steel according to any embodiment of the present invention. The method for bonding Al-Si-coated Boron steel to another component (which may also be a Al-Si-coated Boron steel component from which at least part of its Al-Si coating has been selectively removed using a method according to the present invention) namely comprises the steps of bonding an offer strip to the Al-Si-coated Boron steel using an adhesive, curing the adhesive, whereby the adhesive adheres to the Al-Si coating, and subjecting the offer strip to a peel and/or shear force to mechanically remove at least part of the Al-Si coating from the Al-Si-coated Boron steel and thereby provide at least one uncoated point/line/area on the Al-Si-coated Boron steel, and then bonding the component to the at least one uncoated point/line/area.
- According to an embodiment of the invention the adhesive comprises a crash-durable structural adhesive or a high strength structural adhesive.
- According to an embodiment of the invention the component is bonded to the at least one uncoated point/line/area by means of adhesion.
- According to an embodiment of the invention the adhesive is also used to bond the component to the at least one uncoated point/line/area, i.e. either the same adhesive is used to provide the final permanent bond between the uncoated Boron steel and the component and the temporary bond between the offer strip and the Al-Si-coated Boron steel, or different adhesives are used for each of these bonds.
- According to an embodiment of the invention the component is bonded to the at least one uncoated point/line/area by means of welding, such as by resistance spot welding, laser welding, arc welding, or any other bonding method.
- According to an embodiment of the invention the offer strip comprises one of the following: steel, a high strength steel, an uncoated or hot-dip galvanized coated steel.
- According to an embodiment of the invention the component at least one of the following: a vehicle component, such as a vehicle pillar, a tailor roller blank (TRB), a steel component, such as a component comprising coated or uncoated automotive grade steel or a component comprising coated or uncoated automotive grade Boron steel, an aluminium component, such as a component comprising automotive grade aluminium. The Al-Si-coated steel and/or the component that is attached thereto may comprise hardened Boron steel, which comprises martensitic material, having a tensile strength of 1300 MPa or more.
- The present invention further concerns the use of a coating-removal and/or bonding method according to any of the embodiments of the invention to provide Al-Si-coated (preferably automotive-grade) Boron steel with at least one robust, durable and crash durable bond.
- The present invention will hereinafter be further explained by means of non-limiting examples with reference to the appended schematic figures in which;
- Figure 1
- shows the steps of a method according to an embodiment of the invention,
- Figure 2
- shows the region between Al-Si-coated Boron steel and an offer strip that has been bonded thereto,
- Figure 3
- is a flow diagram showing the steps of a method according to an embodiment of the invention, and
- Figure 4
- shows a vehicle comprising at components that have been bonded together using a method according to the invention.
- It should be noted that the drawings may not have been drawn to scale and that the dimensions of certain features may have been exaggerated for the sake of clarity.
-
Figure 1a ) showsBoron steel 10, having a surface comprising an Aluminium-Silicon (Al-Si) coating 11. The Boron steel may constitute at least part of a Boron steel component of any size and shape. Any known manufacturing method may be used to produce and coat such a Boron steel component. A component may for example be manufactured by hot forming which involves heating blanks of Boron steel to austenitization temperature in a furnace, for example to a temperature over 900°C, and then quenching and shaping it during controlled cooling processes in order to impart different strengths to different parts of the Boron steel component. The Al-Sicoating 11 need not necessarily be uniformly applied to the entire surface ofBoron steel 10 but can be applied to any part or parts of the surface of Boronsteel 10 in any uniform or non-uniform pattern, and/or it may have a uniform or non-uniform thickness as desired. - The method according to the present invention comprises the step of bonding an
offer strip 12 to the Al-Sicoating 11 of the Boronsteel 10 using an adhesive 13. The adhesive 13 may be a crash-durable structural adhesive or a high strength structural adhesive. - The adhesive 13 is namely applied to one or more parts of the Al-
Si coating 11 and/or one or more parts of theoffer strip 12 as desired. Theoffer strip 12 may comprise: steel, a high strength steel, an uncoated or hot-dip galvanized coated steel or any other material that is suitable for being bonded to the Al-Si coating 11 ofBoron steel 10 and then being peeled and/or sheared off therefrom. - In the embodiment illustrated in
Figure 1 , adhesive 13 is applied to the Al-Si coating 11 and/or the surface of theoffer strip 12 in such a way that the entire Al-Si coating of the Al-Si-coatedBoron steel 10 will be bonded to theoffer strip 12 when theoffer strip 12 is joined to the Al-Si-coatedBoron steel 10. The adhesive 13 is cured in order to form an adhesive bond with the Al-Si coating 11 as shown infigure 1b ). - Once the adhesive 13 has been cured, the
offer strip 12 is subjected to a peel and/or shear force Fpeel and/or Fshear, to mechanically remove at least part of the Al-Si coating 11 from the Al-Si-coatedBoron steel 10. In the illustrated embodiment, the entire Al-Si coating 11 is mechanically removed from the surface of the Al-Si-coatedBoron steel 10. - Once the Al-
Si coating 11 has been mechanically removed in part, or in its entirety as desired, theBoron steel 10 will have been provided with at least one uncoated point/line/area 14 as shown infigure 1c ) to which one ormore components 15 can be bonded as shown infigure 1d ). It may for example be beneficial in some applications not to remove the entire Al-Si coating 11 so that it can provide some oxidation and/or corrosion protection. - The
component 15 may be bonded to the at least one uncoated point/line/area 14 by means of adhesion, for example using thesame adhesive 13, or a different adhesive as that used to temporarily bond theoffer strip 12 to the Al-Si coating 11 of theBoron steel 10. - Alternatively, or additionally the
component 15 may be bonded to the at least one uncoated point/line/area 1 by means of welding. - A metallurgical structure analysis may be used to determine that at least part of an Al-
Si coating 11 has been removed from Al-Si- coated Boron steel at the uncoated bond point(s)/line(s)/area(s). The adhesive or welding bond thus formed will be much more robust, durable and crash durable than if at least part of the Al-Si coating 11 had not been removed prior to the formation of such a bond. - The
component 15 may be a vehicle component, such as a vehicle pillar, a tailor roller blank (TRB), a steel component, such as a component comprising coated or uncoated automotive grade steel or a component comprising coated or uncoated automotive grade Boron steel, an aluminium component, such as a component comprising automotive grade aluminium. -
Figure 2 shows the region betweenBoron steel 10 comprising an Al-Si coating 11 and anoffer strip 12 that has been bonded thereto by means of an adhesive 13. Asorption interphase 16 comprising oil and low molecular weight polymer, oriented fillers etc. may form between the adhesive 13 and the Al-Si coating 11. Theoffer strip 12 may also comprise asurface layer 17, such as an oxide or Zn-layer. -
Figure 3 is a flow diagram showing the steps of a method according to an embodiment of the invention. The method comprises the steps of selectively bonding anoffer strip 12 to Al-Si-coatedBoron steel 10 using an adhesive 13, curing the adhesive 13 and subjecting theoffer strip 12 to a peel and/or shear force Fpeel and/or Fshear to mechanically remove at least part of the Al-Si coating 11 from theBoron steel 10 and thereby provide at least one uncoated point, line orarea 14 to which one ormore components 15 may be bonded. -
Figure 4 shows avehicle 18 that comprises at least one component that has been subjected to a method according to the present invention during the manufacture of thevehicle 18. - For example, a vehicle pillar, such as an A-pillar 19 or a B-
pilllar 20 may comprise Al-Si-coated Boron steel from which at least part of the Al-Si coating has been removed using a method according to the present invention and/or a which has been bonded to another component using a method according to the present invention. - For example, the A-pillar 19 of the vehicle, (i.e. the structural support on a side of a vehicle's windscreen located just ahead of and above the vehicle's front doors or roof rail, i.e. the structural component that extends between the roof and the side of the vehicle), may comprise at least two component parts that have been bonded together using a method according to the present invention. A first upper component part of the A-pillar 19 may comprise automotive grade steel having a tensile strength of 800 MPa or less. A second lower part of the A-pillar 19 may comprise hardened Boron steel comprising martensitic material having a tensile strength of 1300 MPa or more. The two component parts may be bonded together, for example by means of adhesion or welding, using a method according to the present invention in order to improve the strength and the durability of the bond formed between them.
- According to an embodiment of the invention the component may constitute a tailor rolled blank (TRB). A TRB or "tailored blank" is a metal sheet, which is typically composed of various steel grades and thicknesses. This allows different parts of a vehicle reinforcement manufactured from the TRB to be adapted to local loads, which would otherwise require additional strengthening components. Benefits of using TRBs therefore include reducing component weight and manufacturing costs. Typically, individual sheet metal plates are welded together by laser welding to produce a TRB.
- A component comprising Boron steel is stiffer and more lightweight than a corresponding component comprising normal steel on account of the alloys that have been added during manufacture, thereby making a vehicle having at least one such component safer and more fuel-efficient than a vehicle that does not comprise Boron steel components.
- Such a
vehicle 18 having suchBoron steel components - Further modifications of the invention within the scope of the claims would be apparent to a skilled person.
Claims (11)
- Method for selectively removing at least part of an Aluminium-Silicon (Al-Si) coating (11) from Al-Si-coated Boron steel (10), characterized in that it comprises the steps of bonding an offer strip (12) to said Al-Si-coated Boron steel (10) using an adhesive (13), curing said adhesive (13), whereby said adhesive (13) adheres to said Al-Si coating (11), and subjecting said offer strip (12) to a peel and/or shear force (Fpeel and/or Fshear) to mechanically remove at least part of said Al-Si coating (11) from said Al-Si-coated Boron steel (10).
- Method according to claim 1, characterized in that said adhesive (13) comprises a crash-durable structural adhesive or a high strength structural adhesive.
- Method according to claim 1, characterized in that said offer strip (12) comprises one of the following: steel, a high strength steel, an uncoated or hot-dip galvanized coated steel.
- Method for bonding Aluminium-Silicon (Al-Si)-coated Boron steel (10) to another component (15), characterized in that it comprises the steps of bonding an offer strip (12) to said Al-Si-coated Boron steel (10) using an adhesive (13), curing said adhesive (13), whereby said adhesive (13) adheres to said Al-Si coating (11), and subjecting said offer strip (12) to a peel and/or shear force (Fpeel and/or Fshear) to mechanically remove at least part of said Al-Si coating (11) from said Al-Si-coated Boron steel (10) and thereby provide at least one uncoated point/line/area (14) on said Al-Si-coated Boron steel (10), and then bonding said component (15) to said at least one uncoated point/line/area (14).
- Method according to claim 3, characterized in that said adhesive (13) comprises a crash-durable structural adhesive or a high strength structural adhesive.
- Method according to claim 3 or 4, characterized in that said component (15) is bonded to said at least one uncoated point/line/area (14) by means of adhesion.
- Method according to claim 5, characterized in that said adhesive (13) is also used to bond said component (15) to said at least one uncoated point/line/area (14).
- Method according to claim 3 or 4, characterized in that said component (15) is bonded to said at least one uncoated point/line/area (14) by means of welding.
- Method according to any of claims 3-8, characterized in that said offer strip (12) comprises one of the following: steel, a high strength steel, an uncoated or hot-dip galvanized coated steel.
- Method according to any of claims 3-9, characterized in that said component (15) at least one of the following: a vehicle component, such as a vehicle pillar (19), a tailor roller blank (TRB), a steel component, such as a component comprising coated or uncoated automotive grade steel or a component comprising coated or uncoated automotive grade Boron steel, an aluminium component, such as a component comprising automotive grade aluminium.
- Use of a method according to any of the preceding claims to provide Al-Si-coated Boron steel (10) with robust, durable and crash durable bonds.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP15200622.7A EP3181716A1 (en) | 2015-12-17 | 2015-12-17 | Robust crash durable adhesive bonding of boron steel |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP15200622.7A EP3181716A1 (en) | 2015-12-17 | 2015-12-17 | Robust crash durable adhesive bonding of boron steel |
Publications (1)
Publication Number | Publication Date |
---|---|
EP3181716A1 true EP3181716A1 (en) | 2017-06-21 |
Family
ID=55129406
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP15200622.7A Withdrawn EP3181716A1 (en) | 2015-12-17 | 2015-12-17 | Robust crash durable adhesive bonding of boron steel |
Country Status (1)
Country | Link |
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EP (1) | EP3181716A1 (en) |
-
2015
- 2015-12-17 EP EP15200622.7A patent/EP3181716A1/en not_active Withdrawn
Non-Patent Citations (2)
Title |
---|
KRELING ET AL: "ADHESIVE BONDING OF PRESS-HARDENED HIGH-STRENGTH STEELS FOR AUTOMOTIVE APPLICATIONS", 4 September 2015 (2015-09-04), XP055250191, Retrieved from the Internet <URL:https://www.researchgate.net/profile/Stefan_Kreling/publication/266892782_ADHESIVE_BONDING_OF_PRESS-HARDENED_HIGH-STRENGTH_STEELS_FOR_AUTOMOTIVE_APPLICATIONS/links/55e974d308ae65b6389af4d0.pdf?inViewer=0&pdfJsDownload=0&origin=publication_detail> [retrieved on 20160215] * |
MAN-SHIN TAN ET AL: "Adhesively Bonded Steel Structures", 1 May 2011 (2011-05-01), XP055250169, Retrieved from the Internet <URL:http://publications.lib.chalmers.se/records/fulltext/152928.pdf> [retrieved on 20160215] * |
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