CN111482605A - 一种无铁磁性立方织构复合基带及其制备方法 - Google Patents

一种无铁磁性立方织构复合基带及其制备方法 Download PDF

Info

Publication number
CN111482605A
CN111482605A CN202010406825.9A CN202010406825A CN111482605A CN 111482605 A CN111482605 A CN 111482605A CN 202010406825 A CN202010406825 A CN 202010406825A CN 111482605 A CN111482605 A CN 111482605A
Authority
CN
China
Prior art keywords
composite
red copper
stainless steel
layer
ferromagnetic
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.)
Pending
Application number
CN202010406825.9A
Other languages
English (en)
Inventor
陈靖
孙敏
翟学珍
刘德伟
李子炯
代海洋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Zhengzhou University of Light Industry
Original Assignee
Zhengzhou University of Light Industry
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 Zhengzhou University of Light Industry filed Critical Zhengzhou University of Light Industry
Priority to CN202010406825.9A priority Critical patent/CN111482605A/zh
Publication of CN111482605A publication Critical patent/CN111482605A/zh
Pending legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/10Sintering only
    • B22F3/105Sintering only by using electric current other than for infrared radiant energy, laser radiation or plasma ; by ultrasonic bonding
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21BROLLING OF METAL
    • B21B1/00Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D1/00General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26Methods of annealing
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D9/00Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22FCHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/08Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of copper or alloys based thereon
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21BROLLING OF METAL
    • B21B1/00Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • B21B2001/221Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length by cold-rolling
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21BROLLING OF METAL
    • B21B1/00Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • B21B2001/225Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length by hot-rolling
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C2204/00End product comprising different layers, coatings or parts of cermet

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Optics & Photonics (AREA)
  • Manufacturing & Machinery (AREA)
  • Metal Rolling (AREA)

Abstract

本发明公开了一种无铁磁性立方织构复合基带及其制备方法,该复合基带为层状结构,从上至下依次为紫铜层/Ni层/304不锈钢层/Ni层/紫铜层,且上下紫铜层厚度相等,上下Ni层厚度相等,合理设计层间厚度比和各层的初始状态,采用放电等离子体烧结获得复合坯锭,然后通过热轧,冷轧,中间退火及最终的再结晶退火获得高强度的复合基带,该复合基带在液氮温区无铁磁性,并具有强立方织构。

Description

一种无铁磁性立方织构复合基带及其制备方法
技术领域
本发明涉及一种在液氮温区无铁磁性的立方织构复合基带及其制备方法,属于第二代高温涂层超导体用的织构金属基底材料制备领域。
背景技术
实用化的涂层超导带材要求具有较高的临界电流密度、较小的交流损耗以及较高的力学性能。目前,第二代高温涂层超导带材主要由金属基底、缓冲层及超导层组成,基底材料又分为强立方织构型和无织构型,对于具有强立方织构的金属基带而言,需要有较高的强度,同时在液氮温区应具有较低的铁磁性,镍基合金,如镍钨合金具有较高的强度,钨原子含量较高时,铁磁性将降低,但立方织构的含量也随之减少,难以同时实现强立方织构、无铁磁性和较高的力学性能。通过复合基带的设计思路可以获得良好的力学性能,同时可以兼顾铁磁性和立方织构,但是目前主要集中在不同成分的镍基合金的复合材料中,对于低成本的高性能复合基带研究的较少,因此,基于低成本织构金属基带制备技术,开发新的合金体系及相应的基带制备技术具有重要的科学价值和工业意义。
发明内容
本发明的目的是提供一种无铁磁性立方织构复合基带及其制备方法,通过多层结构的设计思路及相应的制备工艺,开发适合第二代涂层超导带材用的高性能织构金属基带。
为解决上述技术问题,本发明采用以下技术方案:
本发明所提供的一种无铁磁性立方织构复合基带,所述复合基带的层状结构为:紫铜/Ni/304不锈钢/Ni/紫铜,且上下紫铜层厚度相等,上下Ni层厚度也相等。
本发明无铁磁性立方织构复合基带的制备方法,包括以下步骤:
(1)复合坯锭的制备工艺:
紫铜板的制备工艺为:将熔炼法获得的紫铜热轧至9~12mm,然后冷轧至3~5mm厚,304不锈钢为熔铸法获得,厚度为3~5mm,Ni的纯度为99.9%及以上,厚度为0.5~0.8mm。复合坯锭的制备工艺为:先制备Ni/304不锈钢/Ni复合坯锭,采用放电等离子体烧结的方法获得层状Ni/304不锈钢/Ni复合坯锭,烧结过程中以100℃/min的升温速率升至850℃~980℃,保温5~10min,压力为45Mpa~50Mpa;然后再通过以紫铜板为外层材料,Ni/304不锈钢/Ni复合坯锭为芯层材料,采用放电等离子体烧结获得紫铜/Ni/304不锈钢/Ni/紫铜的层状复合坯锭,烧结过程中以100℃/min的升温速率升至750℃~800℃,保温5~10min,压力为45Mpa~50Mpa。
(2)复合坯锭的热轧
将上述复合坯锭升温至1000℃保温5min后进行热轧,总变形量为50%~60%,热轧过程仅用一道次来完成。
(3)冷轧及中间退火
将上述热轧复合板冷轧至3mm厚,然后在500℃保温30min,退火后再继续冷轧至100μm厚。
(4)冷轧带材的再结晶退火
将冷轧带材进行再结晶退火,具体工艺:900℃~980℃保温30min~45min。
本发明的有益效果:本发明以高强度的不锈钢作为芯层材料,可以有效提升复合基带整体力学性能。在紫铜板中容易获得强立方织构,并且Cu与Ni可以无限固溶,外层采用紫铜板与Ni板结合,获得良好的界面结合,同时在表面形成强立方织构。
附图说明
图1为实施例1中最终复合基带表面的取向差分布图。
具体实施方式
下面结合具体实施例,对本发明做进一步说明。应理解,以下实施例仅用于说明本发明而非用于限制本发明的范围,该领域的技术熟练人员可以根据上述发明的内容作出一些非本质的改进和调整。
实施例1
本实施例复合基带的结构为:以紫铜板/Ni/304不锈钢板/Ni/紫铜板的顺序叠加形成层状复合坯锭,且上下紫铜层厚度相等,上下Ni层厚度也相等。
本实施例复合基带的制备方法如下:
(1)紫铜板的制备工艺为:将熔炼法获得的紫铜热轧至9mm,然后冷轧至3mm厚,304不锈钢为熔铸法获得,厚度为3mm,Ni的纯度为99.9%及以上,厚度为0.5mm。复合坯锭的制备工艺为:先制备Ni/304不锈钢/Ni复合坯锭,采用放电等离子体烧结的方法获得层状Ni/304不锈钢/Ni复合坯锭,烧结过程中以100℃/min的升温速率升至850℃,保温5min,压力为45Mpa;然后再通过以紫铜板为外层材料,Ni/304不锈钢/Ni复合坯锭为芯层材料,采用放电等离子体烧结获得紫铜/Ni/304不锈钢/Ni/紫铜的层状复合坯锭,烧结过程中以100℃/min的升温速率升至750℃,保温5min,压力为45Mpa。
(2)将上述复合坯锭升温至1000℃保温5min后进行热轧,总变形量为60%,热轧过程仅用一道次来完成。
(3)将上述热轧复合板冷轧至3mm厚,然后在500℃保温30min,退火后再继续冷轧至100μm厚。
(4)将冷轧带材进行再结晶退火,具体工艺:900℃保温30min。
该复合基带表面的取向差分布如图1所示,其屈服强度达到252MPa,在液氮温区无铁磁性。
实施例2
本实施例复合基带的结构为:以紫铜板/Ni/304不锈钢板/Ni/紫铜板的顺序叠加形成层状复合坯锭,且上下紫铜层厚度相等,上下Ni层厚度也相等。
本实施例复合基带的制备方法如下:
(1)紫铜板的制备工艺为:将熔炼法获得的紫铜热轧至12mm,然后冷轧至5mm厚,304不锈钢为熔铸法获得,厚度为3mm,Ni的纯度为99.9%及以上,厚度为0.8mm。复合坯锭的制备工艺为:先制备Ni/304不锈钢/Ni复合坯锭,采用放电等离子体烧结的方法获得层状Ni/304不锈钢/Ni复合坯锭,烧结过程中以100℃/min的升温速率升至980℃,保温5min,压力为50Mpa;然后再通过以紫铜板为外层材料,Ni/304不锈钢/Ni复合坯锭为芯层材料,采用放电等离子体烧结获得紫铜/Ni/304不锈钢/Ni/紫铜的层状复合坯锭,烧结过程中以100℃/min的升温速率升至800℃,保温5min,压力为50Mpa。
(2)将上述复合坯锭升温至1000℃保温5min后进行热轧,总变形量为50%,热轧过程仅用一道次来完成。
(3)将上述热轧复合板冷轧至3mm厚,然后在500℃保温30min,退火后再继续冷轧至100μm厚。
(4)将冷轧带材进行再结晶退火,具体工艺:980℃保温30min。该复合基带的屈服强度达到了230MPa,在液氮温区无铁磁性。
实施例3
本实施例复合基带的结构为:复合坯锭的结构为:以紫铜板/Ni/304不锈钢板/Ni/紫铜板的顺序叠加形成层状复合坯锭,且上下紫铜层厚度相等,上下Ni层厚度也相等。
本实施例复合基带的制备方法如下:
(1)紫铜板的制备工艺为:将熔炼法获得的紫铜热轧至9mm,然后冷轧至5mm厚,304不锈钢为熔铸法获得,厚度为5mm,Ni的纯度为99.9%及以上,厚度为0.8mm。复合坯锭的制备工艺为:先制备Ni/304不锈钢/Ni复合坯锭,采用放电等离子体烧结的方法获得层状Ni/304不锈钢/Ni复合坯锭,烧结过程中以100℃/min的升温速率升至850℃,保温10min,压力为45Mpa;然后再通过以紫铜板为外层材料,Ni/304不锈钢/Ni复合坯锭为芯层材料,采用放电等离子体烧结获得紫铜/Ni/304不锈钢/Ni/紫铜的层状复合坯锭,烧结过程中以100℃/min的升温速率升至800℃,保温10min,压力为50Mpa。
(2)将上述复合坯锭升温至1000℃保温5min后进行热轧,总变形量为60%,热轧过程仅用一道次来完成。
(3)将上述热轧复合板冷轧至3mm厚,然后在500℃保温30min,退火后再继续冷轧至100μm厚。
(4)将冷轧带材进行再结晶退火,具体工艺:900℃~980℃保温30min。该复合基带的屈服强度达到了263MPa,在液氮温区无铁磁性。
以上显示和描述了本发明的基本原理和主要特征以及本发明的优点。本行业的技术人员应该了解,本发明不受上述实施例的限制,上述实施例和说明书中描述的只是说明本发明的原理,在不脱离本发明精神和范围的前提下,本发明还会有各种变化和改进,这些变化和改进都落入要求保护的本发明范围内。本发明要求保护范围由所附的权利要求书及其等效物界定。

Claims (6)

1.一种无铁磁性立方织构复合基带,其特征在于:所述复合基带为层状结构,从上至下依次为紫铜层/Ni层/304不锈钢层/Ni层/紫铜层,且上下紫铜层厚度相等,上下Ni层厚度相等。
2.根据权利要求1所述的无铁磁性立方织构复合基带的制备方法,其特征在于包括以下步骤:
(1)复合坯锭的制备工艺:
a、先制备Ni/304不锈钢/Ni复合坯锭,采用放电等离子体烧结的方法获得层状Ni/304不锈钢/Ni复合坯锭,烧结过程中以100℃/min的升温速率升至850℃~980℃,保温5~10min,压力为45Mpa~50Mpa;
b、然后再以紫铜板为外层材料,Ni/304不锈钢/Ni复合坯锭为芯层材料,采用放电等离子体烧结获得紫铜/Ni/304不锈钢/Ni/紫铜的层状复合坯锭;
(2)复合坯锭的热轧:将步骤(1)制得的复合坯锭升温至1000℃保温5min后进行热轧,总变形量为50%~60%,热轧过程仅用一道次来完成;
(3)冷轧及中间退火:将步骤(2)热轧后得到的复合板冷轧至厚度为3mm,然后在500℃保温30min,退火后再继续冷轧至厚度为100μm得到冷轧带材;
(4)冷轧带材的再结晶退火:将步骤(3)得到的冷轧带材在900℃~980℃的条件下保温30min~45min进行再结晶退火。
3.根据权利要求2所述的无铁磁性立方织构复合基带的制备方法,其特征在于:所述步骤(1)a采用放电等离子体烧结过程中以100℃/min的升温速率升至850℃~980℃,保温5~10min,压力为45Mpa~50Mpa。
4.根据权利要求2所述的无铁磁性立方织构复合基带的制备方法,其特征在于:所述步骤(1)b采用放电等离子体烧结过程中以100℃/min的升温速率升至750℃~800℃,保温5~10min,压力为45Mpa~50Mpa。
5.根据权利要求2所述的无铁磁性立方织构复合基带的制备方法,其特征在于:所述步骤(1)a中304不锈钢为熔铸法获得,厚度为3~5mm,Ni的纯度为99.9%及以上,厚度为0.5~0.8mm。
6.根据权利要求2所述的无铁磁性立方织构复合基带的制备方法,其特征在于:所述步骤(1)b中紫铜板的制备工艺为:将熔炼法获得的紫铜热轧至9~12mm,然后冷轧至厚度为3~5mm。
CN202010406825.9A 2020-05-14 2020-05-14 一种无铁磁性立方织构复合基带及其制备方法 Pending CN111482605A (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010406825.9A CN111482605A (zh) 2020-05-14 2020-05-14 一种无铁磁性立方织构复合基带及其制备方法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010406825.9A CN111482605A (zh) 2020-05-14 2020-05-14 一种无铁磁性立方织构复合基带及其制备方法

Publications (1)

Publication Number Publication Date
CN111482605A true CN111482605A (zh) 2020-08-04

Family

ID=71790848

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010406825.9A Pending CN111482605A (zh) 2020-05-14 2020-05-14 一种无铁磁性立方织构复合基带及其制备方法

Country Status (1)

Country Link
CN (1) CN111482605A (zh)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK1420900T3 (da) * 2001-08-30 2006-04-03 Leibniz Inst Fuer Festkoerper Fremgangsmåde til fremstilling af metalliske bånd
CN101786352A (zh) * 2010-01-15 2010-07-28 北京工业大学 无磁性立方织构Cu基合金复合基带及制备方法
CN103531305A (zh) * 2013-09-28 2014-01-22 北京工业大学 一种涂层导体用铜基/镍基复合长基带的制备方法
CN105537562A (zh) * 2015-12-21 2016-05-04 河南师范大学 一种无铁磁性、高强度织构铜镍合金复合基带的制备方法
CN106113882A (zh) * 2016-06-21 2016-11-16 河南城建学院 无铁磁性、高强度织构镍钒/铜/镍钨复合基带制备方法
CN111112331A (zh) * 2019-12-30 2020-05-08 河南师范大学 一种高强度的织构复合基带的制备方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK1420900T3 (da) * 2001-08-30 2006-04-03 Leibniz Inst Fuer Festkoerper Fremgangsmåde til fremstilling af metalliske bånd
CN101786352A (zh) * 2010-01-15 2010-07-28 北京工业大学 无磁性立方织构Cu基合金复合基带及制备方法
CN103531305A (zh) * 2013-09-28 2014-01-22 北京工业大学 一种涂层导体用铜基/镍基复合长基带的制备方法
CN105537562A (zh) * 2015-12-21 2016-05-04 河南师范大学 一种无铁磁性、高强度织构铜镍合金复合基带的制备方法
CN106113882A (zh) * 2016-06-21 2016-11-16 河南城建学院 无铁磁性、高强度织构镍钒/铜/镍钨复合基带制备方法
CN111112331A (zh) * 2019-12-30 2020-05-08 河南师范大学 一种高强度的织构复合基带的制备方法

Similar Documents

Publication Publication Date Title
WO2007134515A1 (fr) CEINTURE DE BASE COMPOSITE EN ALLIAGE AU Ni POUR REVÊTEMENT SUPRACONDUCTEUR ET PROCÉDÉ D'ÉLABORATION
CN103060731B (zh) 一种无或低磁性、立方织构Ni-W合金复合基带的制备方法
CN101635185B (zh) 一种无/低磁性立方织构Ni-W合金基带的制备方法
CN101249607A (zh) 一种涂层超导高W含量Ni-W合金基带的制备方法
CN103421985B (zh) 一种无磁性、高强度的织构Cu基三元合金基带的制备方法
CN103498121A (zh) 一种高强度立方织构NiW合金复合基带及其制备方法
CN111101007B (zh) 一种高性能镍基合金复合带材的制备方法
CN106113882B (zh) 无铁磁性、高强度织构镍钒/铜/镍钨复合基带制备方法
CN107267900B (zh) 一种高强度无铁磁性织构铜基合金基带的制备方法
CN103496205B (zh) 一种无磁性、高强度织构Cu基合金复合基带及其制备方法
CN102825857A (zh) 一种无磁性织构Ni基合金复合基带及其制备方法
CN110951995B (zh) 一种高强度镍基合金基带的制备方法
CN109531067B (zh) 一种无铁磁性织构铜镍/镍钨复合基带及其制备方法
CN109930099B (zh) 一种高强度强立方织构Cu-Fe-Zr-P合金基带的制备方法
CN109811310B (zh) 无铁磁性、高强度、强立方织构镍钨复合基带及制备方法
CN111482605A (zh) 一种无铁磁性立方织构复合基带及其制备方法
CN111112331B (zh) 一种高强度的织构复合基带的制备方法
CN109536907B (zh) 一种高强度强立方织构层状复合基带及其制备方法
CN111004943A (zh) 一种高性能镍钒铜磷合金基带的制备方法
CN102154578A (zh) 一种无磁性织构NiV合金基带及其熔炼制备方法
CN105537562A (zh) 一种无铁磁性、高强度织构铜镍合金复合基带的制备方法
US9896746B2 (en) Method for preparing element diffusion-type composite substrate
CN110983109B (zh) 一种立方织构的镍铬钒合金基带的制备方法
CN108300895A (zh) 一种高温超导涂层导体用无磁性立方织构Cu-Ni-Cr合金基带的制造方法
CN111180134A (zh) 一种强立方织构金属复合带材的制备方法

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination