WO2019028157A1 - Fabrication de pièces porteuses à résistance ultra-élevée à l'aide d'aciers à résistance élevée/faible rendement initial par le biais d'un processus d'hydroformage tubulaire - Google Patents

Fabrication de pièces porteuses à résistance ultra-élevée à l'aide d'aciers à résistance élevée/faible rendement initial par le biais d'un processus d'hydroformage tubulaire Download PDF

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Publication number
WO2019028157A1
WO2019028157A1 PCT/US2018/044841 US2018044841W WO2019028157A1 WO 2019028157 A1 WO2019028157 A1 WO 2019028157A1 US 2018044841 W US2018044841 W US 2018044841W WO 2019028157 A1 WO2019028157 A1 WO 2019028157A1
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WO
WIPO (PCT)
Prior art keywords
hydroforming
tube
initial
mpa
steels
Prior art date
Application number
PCT/US2018/044841
Other languages
English (en)
Inventor
Chao PU
Yueqian JIA
Feng Zhu
Yu-Wei Wang
Original Assignee
Ak Steel Properties, Inc.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Ak Steel Properties, Inc. filed Critical Ak Steel Properties, Inc.
Priority to MX2020001313A priority Critical patent/MX2020001313A/es
Priority to CA3069236A priority patent/CA3069236A1/fr
Publication of WO2019028157A1 publication Critical patent/WO2019028157A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
    • B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
    • B21D26/033—Deforming tubular bodies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
    • B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
    • B21D26/033—Deforming tubular bodies
    • B21D26/035—Deforming tubular bodies including an additional treatment performed by fluid pressure, e.g. perforating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
    • B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
    • B21D26/053—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure characterised by the material of the blanks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D31/00—Other methods for working sheet metal, metal tubes, metal profiles
    • B21D31/005—Incremental shaping or bending, e.g. stepwise moving a shaping tool along the surface of the workpiece
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D31/00—Other methods for working sheet metal, metal tubes, metal profiles
    • B21D31/04—Expanding other than provided for in groups B21D1/00 - B21D28/00, e.g. for making expanded metal
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D7/00—Modifying the physical properties of iron or steel by deformation
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D7/00—Modifying the physical properties of iron or steel by deformation
    • C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
    • C21D7/10—Modifying the physical properties of iron or steel by deformation by cold working of the whole cross-section, e.g. of concrete reinforcing bars
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/02—Making uncoated products
    • B21C23/04—Making uncoated products by direct extrusion
    • B21C23/08—Making wire, bars, tubes
    • B21C23/085—Making tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D53/00—Making other particular articles
    • B21D53/88—Making other particular articles other parts for vehicles, e.g. cowlings, mudguards

Definitions

  • BIW parts body in white (BIW) parts to achieve expected structural strength and stiffness or satisfy the packaging constraints.
  • BIW parts are generally considered to be upper body, underbody and/or structural automotive components. While designers are seeking light-weighting solutions, it is always challenging to form complicated geometries with conventional advanced high strength steels (AHSS) due to their limited ductility.
  • AHSS advanced high strength steels
  • Steels with high ultimate tensile strength and relatively low initial yield strength can act as an enabler to manufacture ultra-high strength BIW parts with complex geometry, providing a high ultimate tensile strength (about 1000 MPa or greater) and superior ductility (about 40% elongation or greater).
  • their relatively low initial yield strength of such steels about 360 MPa or lower can hinder their application to manufacturing load- bearing structural parts.
  • Figures la- Id illustrate tube deformation after each manufacturing step in an embodiment of the present process.
  • Figure 2 is an exemplary part made by an embodiment of the
  • Figure 3 is a graph showing the pre-bending pressure load history applied to an initial tube blank to form the exemplary part.
  • Figure 4a-4b shows an initial tube blank for the exemplary part after prebending.
  • Figure 5 shows the initial tube blank outer diameter and wall thickness prior to pre-bending.
  • Figure 6 shows the tube blank outer diameter and wall thickness after the tube blank has undergone hydroforming.
  • Figure 7 shows the wall thinning after hydroforming of the tube blank to form the exemplary part shown in Fig. 2.
  • Figure 8 shows the true hardening stress in the finished exemplary part of Fig. 2.
  • Figure 9 shows the initial tube blank outer diameter and wall thickness prior to pre-bending for a second exemplary part.
  • Figure 10 shows the tube blank outer diameter and wall thickness after the tube blank has undergone hydroforming.
  • Figure 1 1 shows the wall thinning after hydroforming of the tube blank to form the exemplary part of Fig. 9.
  • Figure 12 shows the hardening stress in the finished exemplary part of
  • tubular hydroforming techniques are introduced to synergize with BIW part forming.
  • Such steels can have ultimate tensile strengths of greater than 1000 MPa, preferably greater than 1150 MPa; they have initial yields of less than 360 MPa.
  • the steels have elongation of at least about 40%.
  • Such steels can include retained austenite.
  • the hydroforming manufacturing process of the present embodiments comprises raw tube blanking, tube pre-bending, hydroforming (tube expansion or reduction), and trimming.
  • preforming and intermediate hydroforming are also used to ensure even stretching of the steel.
  • one or both of preforming and intermediate hydroforming may occur between pre- bending and hydroforming.
  • the hydraulic pressure causes the tube to expand until it matches the negative mold.
  • This expansion introduces uniform material stretching and consequently enhances the yield strength by means of material work hardening.
  • the enhancement of yield strength is beneficial for load-bearing structural crash performance of the formed part and enables light-weighting through the application of high ultimate tensile strength/low initial yield materials.
  • the closed section of the hydro-formed tube also can provide stiffness and structural performance.
  • the enhancement of yield strength can be controlled by the amount of tube expansion, i.e., the initial tube blank diameter to the finished tube diameter according to the design specification.
  • the initial tube blank diameter is determined by multiple factors such as initial yield strength of the steel, the targeted yield strength, and stress hardening behavior of the steel. Besides the above factors, initial and final material thickness are required to be considered to meet the final part design target. Each of these factors is known, or able to be determined, by the part designer/manufacturer.
  • the equivalent strain can be defined as
  • D 0 is the initial diameter
  • D is the final part nominal diameter
  • Y 0 is the material initial yield strength
  • Y is the targeting yield strength
  • n is the strain hardening exponent
  • K is the stress coefficient which determined by material stress hardening behavior and stress conditions.
  • the manufacturing process of hydroforming the steels of the present application comprises the following steps:
  • Raw tube blanking (Fig. la): Select a raw tube diameter sufficient to permit stretching in the later hydroforming step thus reaching the desired yield strength, as well as keeping induced material thinning within the failure limits and design tolerance.
  • Pre-bending (Fig. lb): The raw tube is then loaded into a tube bender to generate smooth curvatures in order to achieve more uniform deformation in the later step. The goal is to create smooth curves that makes no wrinkles or large localized stress gradient.
  • the pre-bending is a standardized procedure for hydroforming and this requirement is a common requirement in this step.
  • the present process permits the exploitation of steels with high tensile strength and ductility for manufacturing ultra-high strength BIW parts. It further provides an effective light-weighting solution and enhances uniformly the material yield strength of the parts formed with the steels described herein, including NXG 1200 steel. This solution can promote the applications of steels with high ultimate tensile strengths but low initial yield strength in load-bearing BIW components, or other load bearing components. It also offers design flexibility to formed parts with complex geometric features and expected structural strength. The distribution of material yield strength can be also controlled by the amount of stretching of the steel material.
  • a steel containing retained austenite is used to manufacture a front tube for an automobile, as shown in Fig. 2. Before processing, it has an ultimate tensile strength of 1 150 MPa and an initial yield strength of 360 MPa. The finished part has a 20 mm outer diameter. The initial tube blank has an outer diameter of 16 mm and wall thickness of 2.0 mm.
  • the initial tube blank is created by tube blanking, it is then subject to pre-bending, it is then subjected to hydroforming, and then to trimming.
  • Pre-bending pressure is applied as shown in Fig. 3.
  • the blank is bent in four steps, as shown in Fig. 4a, with the inner bends generating a bend with a radius of 109 mm and the outer bends generating a radius of 200 mm, as shown in Fig. 4b.
  • the tube blank is hydroformed at a pressure of 500 MPa.
  • the initial tube blank has an outer diameter of 16 mm and a wall thickness of 2.0 mm, as shown in Fig. 5.
  • the hydroformed part has an outer diameter of 20 mm with a wall thickness of 1.45 mm at the inner bends and a wall thickness of 1.76 mm, with an average wall thickness of 1.59 mm, as shown in Fig. 6.
  • the average wall thinning is about 20%, and ranges from a minimum thinning in the concave bending area of 12% to a maximum thinning in the convex bending area of 27%, as shown in Fig. 7.
  • the plastic strain ranges from 0.24, which results in a true hardening stress of 1200 MPa at the concave bending area, to 0.27, which results in a hardening stress of 1400 MPa in the flat area, to 0.37, which results in a hardening stress of 1600 MPa in the convex bending areas, all as shown in Fig. 8.
  • a second tube blank was processed according to the process of
  • Example 1 The steel contained retained austenite. Before processing, it has an ultimate tensile strength of 1150 MPa and an initial yield strength of 360 MPa.
  • the tube blank has an outer diameter of 16 mm and a wall thickness of 2.5 mm, as shown in Fig. 9.
  • Example 1 the outer diameter of the hydroformed tube is 20 mm, and the wall thickness varies from 1.80 mm to 2.18 mm, with an average thickness of 1.98 mm, as shown in Fig. 10.
  • the plastic strain ranges from 0.25, which results in a true hardening stress of 1270 MPa at the concave bending area, to 0.28, which results in a hardening stress of 1400 MPa in the flat area, to 0.38, which results in a hardening stress of 1600 MPa in the convex bending areas, all as shown in Fig. 12.
  • An initial tube blank is selected with an initial tube diameter sufficient to permit stretching of the steel in a later hydroforming step to reach a pre-determined yield strength while keeping induced material thinning within pre-determined failure limits and pre-determined design tolerance and forming an initial tube blank conforming to said diameter;
  • Example 4 [0060] The process of Example 3, or any of the following Examples, wherein the steel contains retained austenite.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)
  • Heat Treatment Of Articles (AREA)

Abstract

Au lieu d'utiliser un procédé de formage par estampage classique avec des aciers ayant une résistance ultime à la traction élevée et un rendement initial relativement faible, des techniques d'hydroformage tubulaire sont introduites pour être mises en synergie avec le formage d'une pièce BIW, ou le formage d'autres pièces porteuses. De tels aciers peuvent présenter des résistances ultimes à la traction supérieures à 1000 MPa et des rendements initiaux inférieurs à 360 MPa.Selon certains modes de réalisation, les aciers présentent un allongement d'au moins 40 %.De tels aciers peuvent comprendre de l'austénite résiduelle.
PCT/US2018/044841 2017-08-01 2018-08-01 Fabrication de pièces porteuses à résistance ultra-élevée à l'aide d'aciers à résistance élevée/faible rendement initial par le biais d'un processus d'hydroformage tubulaire WO2019028157A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
MX2020001313A MX2020001313A (es) 2017-08-01 2018-08-01 Fabricacion de partes de rodamiento de carga de resistencia ultra alta que utilizan aceros de alta resistencia/bajo limite inicial, mediante proceso de hidroconformado tubular.
CA3069236A CA3069236A1 (fr) 2017-08-01 2018-08-01 Fabrication de pieces porteuses a resistance ultra-elevee a l'aide d'aciers a resistance elevee/faible rendement initial par le biais d'un processus d'hydroformage tubulaire

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201762539911P 2017-08-01 2017-08-01
US62/539,911 2017-08-01

Publications (1)

Publication Number Publication Date
WO2019028157A1 true WO2019028157A1 (fr) 2019-02-07

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ID=63245088

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2018/044841 WO2019028157A1 (fr) 2017-08-01 2018-08-01 Fabrication de pièces porteuses à résistance ultra-élevée à l'aide d'aciers à résistance élevée/faible rendement initial par le biais d'un processus d'hydroformage tubulaire

Country Status (5)

Country Link
US (1) US20190039110A1 (fr)
CA (1) CA3069236A1 (fr)
MX (1) MX2020001313A (fr)
TW (1) TW201919788A (fr)
WO (1) WO2019028157A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040031309A1 (en) * 2000-10-10 2004-02-19 Leif Carlsson Method and a device for manufacturing of a closed profile and a profile manufactured according to said method
JP2006116595A (ja) * 2004-09-21 2006-05-11 Nissan Motor Co Ltd 液圧成形装置及び液圧成形方法
KR20130002220A (ko) * 2011-06-28 2013-01-07 현대하이스코 주식회사 하이드로포밍을 이용한 고강도 강 부품 제조 방법

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170268086A1 (en) * 2016-03-17 2017-09-21 Ford Global Technologies, Llc Recovery heat treatment of highly strained components
US20180010204A1 (en) * 2016-07-08 2018-01-11 The Nanosteel Company, Inc. High yield strength steel

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040031309A1 (en) * 2000-10-10 2004-02-19 Leif Carlsson Method and a device for manufacturing of a closed profile and a profile manufactured according to said method
JP2006116595A (ja) * 2004-09-21 2006-05-11 Nissan Motor Co Ltd 液圧成形装置及び液圧成形方法
KR20130002220A (ko) * 2011-06-28 2013-01-07 현대하이스코 주식회사 하이드로포밍을 이용한 고강도 강 부품 제조 방법

Also Published As

Publication number Publication date
CA3069236A1 (fr) 2019-02-07
US20190039110A1 (en) 2019-02-07
MX2020001313A (es) 2020-03-20
TW201919788A (zh) 2019-06-01

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