JPH07173587A - Production of zirconium alloy welded member - Google Patents

Production of zirconium alloy welded member

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Publication number
JPH07173587A
JPH07173587A JP32037693A JP32037693A JPH07173587A JP H07173587 A JPH07173587 A JP H07173587A JP 32037693 A JP32037693 A JP 32037693A JP 32037693 A JP32037693 A JP 32037693A JP H07173587 A JPH07173587 A JP H07173587A
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Japan
Prior art keywords
corrosion resistance
zr
β
α
welding
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
JP32037693A
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Japanese (ja)
Inventor
Katsuhiro Abe
Mitsuo Kanehara
Takanari Okuda
隆成 奥田
勝洋 安部
光男 金原
Original Assignee
Kobe Steel Ltd
株式会社神戸製鋼所
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Priority to JP32037693A priority Critical patent/JPH07173587A/en
Publication of JPH07173587A publication Critical patent/JPH07173587A/en
Application status is Pending legal-status Critical

Links

Abstract

PURPOSE: To produce a Zr allay welded member free from deterioration of the corrosion resistance of the weld zone by subjecting an (α+β) type Zr alloy to welding and thereafter executing specified cold working and heat treatment.
CONSTITUTION: An (α+β) type Zr allay contg. about 1 to 20wt.% Nb as a stabilizing element is subjected to welding. After that, this welded member is subjected to cold working at 5 to 30% draft and is next subjected to heat treatment at 520 to 600°C for about 30min to 10hr. By this treatment, residual strains are relaxed without causing defects on the weld zone, and a (β-Zr phase formed by the welding is transformed into an α-Zr phase and a (β-Nb phase good in corrosion resistance. Thus, the corrosion resistance of the weld zone is improved, by which the (α+β) type Zr alloy welded member free from deterioration in the corrosion resistance of the weld zone can be obtd.
COPYRIGHT: (C)1995,JPO

Description

【発明の詳細な説明】 DETAILED DESCRIPTION OF THE INVENTION

【0001】 [0001]

【産業上の利用分野】本発明は溶接部の耐食性が劣化しないジルコニウム合金溶接部材の製造方法に関する。 The present invention relates to a manufacturing method of zirconium alloy welding member corrosion resistance of the welded part is not degraded.

【0002】 [0002]

【従来の技術】原子炉(軽水炉)に使用される燃焼チャンネルや燃料被覆管等の炉心部材は、中性子吸収断面積が小さく、高温・高圧下での純水あるいは水蒸気に対する耐食性が良好で、かつ適切な強度および延性を持つジルコニウム合金により形成されている。 BACKGROUND ART reactor core member such as a combustion channels and fuel cladding tube used in (LWR) is the neutron absorption cross section is small, good corrosion resistance in pure water or water vapor at high temperature and high pressure, and It is formed by zirconium alloys with adequate strength and ductility. 従来、かかるジルコニウム合金として、ジルコニウムに若干の元素(F Conventionally, as such a zirconium alloy, some of the elements zirconium (F
e、Cr、Ni)を添加して耐食性を改善したジルカロイと呼ばれるα型ジルコニウム合金(例えば、ジルカロイ−2、ジルカロイ−4)が使用されてきた。 e, Cr, Ni) added to α-type zirconium alloy called Zircaloy having improved corrosion resistance (e.g., Zircaloy-2, Zircaloy-4) have been used.

【0003】近年、軽水炉による原子力発電コストの低減のため、高燃焼化が計画されており、かかる条件の下ではα型ジルコニウム合金では機械的強度が不十分になり、クリープ現象などにより変形し、原子炉の運転に支障が来すおそれがあった。 Recently, in order to reduce the nuclear power costs LWR, high burn reduction are planned, the mechanical strength becomes insufficient at the α-type zirconium alloy under these conditions, is deformed due to creep, interfere with the operation of the reactor there is a risk of causing. そこで、炉心部材を(α+ Thus, the core member (α +
β)型ジルコニウム合金で製作することが試みられている。 It has been attempted to manufacture in beta) type zirconium alloy. (α+β)型ジルコニウム合金は優れた耐食性を有し、中性子吸収断面積が小さく、加工性も優れており、 (Alpha + beta) type zirconium alloys have excellent corrosion resistance, neutron absorption cross section is small, it has excellent workability,
しかもα型ジルコニウム合金より機械的強度が高いからである。 Moreover it is highly mechanical strength than α-type zirconium alloy. このような(α+β)型ジルコニウム合金としては、Zrにβ安定化元素であるNbを2.6wt%含有させたZr−2.5%Nb合金が代表的である。 Such (alpha + beta) type zirconium alloy, Zr-2.5% Nb alloy which contains 2.6 wt% of Nb is beta stabilizing element Zr are typical.

【0004】 [0004]

【発明が解決しようとする課題】しかしながら、(α+ The object of the invention is to, however, (α +
β)型ジルコニウム合金に溶接加工を施すと、溶接部の耐食性が劣化し、マトリックスに較べて酸化が速やかに進行し、厚膜化した酸化膜が形成される。 When subjected to welding to the beta) type zirconium alloy, corrosion resistance of the weld is deteriorated, the oxidation proceeds rapidly compared to the matrix, thickened the oxide film is formed. その結果、溶接部の肉厚が減少し、強度の低下を招く。 As a result, the thickness of the welded portion is reduced, leading to decrease in strength. 本発明はかかる問題に鑑みなされたものであり、溶接部の耐食性が劣化しない(α+β)型ジルコニウム合金溶接部材の製造方法を提供することを目的とする。 The present invention has been made in view of such problems, and an object thereof is to provide a method for producing the corrosion resistance of the welded part is not degraded (alpha + beta) type zirconium alloy welding member.

【0005】 [0005]

【課題を解決するための手段】本発明のジルコニウム合金溶接部材の製造方法は、(α+β)型ジルコニウム合金に対して溶接加工を行った後、加工率が5〜30%の冷間加工を行い、次いで520〜600℃の熱処理を行う。 Method for producing a zirconium alloy welding member of the present invention In order to achieve the above object, according, (alpha + beta) type after welding against a zirconium alloy, working ratio performs processing between 5-30% cold , followed by a heat treatment of the five hundred twenty to six hundred ° C.. 尚、本発明の製造対象となる(α+β)型ジルコニウム合金としては、既述のZr−2.5%Nb合金に限らず、常温での組織が(α+β)相である、Nb含有量が1〜20wt%のジルコニウム合金であればいずれのものでも適用可能である。 As the production subject to (alpha + beta) type zirconium alloy of the present invention is not limited to the Zr-2.5% Nb alloy described above, a tissue at normal temperature (alpha + beta) phase, Nb content is 1 if 20 wt% zirconium alloy be any applicable.

【0006】 [0006]

【作用】(α+β)型ジルコニウム合金の溶接部には、 [Action] the weld (alpha + beta) type zirconium alloy,
溶接の加熱冷却に伴い、残留歪およびβ−Zr相が生成し、これにより耐食性が劣化する。 With the heating and cooling of the weld, residual strain and beta-Zr phase is generated, thereby the corrosion resistance is degraded. すなわち、(α+ In other words, (α +
β)型ジルコニウム合金に溶接加工を施すと、溶接部は一度溶解した後に凝固したミクロ組織、換言すれば針状組織になる。 When subjected to welding to the beta) type zirconium alloy, weld becomes microstructure, in other words acicular structure solidified after dissolving once. この針状組織の形態は、溶接後の冷却速度により異なる。 Form of this acicular structure is different depending on the cooling rate after welding. 冷却速度が速い(約80℃/秒以上)場合には、Nbを過飽和に固溶し、残留歪の非常に多いマルテンサイト組織になる。 If the cooling rate is fast (about 80 ° C. / sec or more), a solid solution of Nb in supersaturation becomes very large martensite structure of residual strain. 一方、冷却速度が遅い場合には、マルテンサイト組織に比して残留歪が軽減されるものの、Nbを約0.5%固溶したα−Zr相と、Nbを約20%固溶したβ−Zr相とが混ざり合った針状組織となる。 On the other hand, when the cooling rate is slow, although the residual strain is reduced as compared with the martensite structure, and alpha-Zr phase and a solid solution of about 0.5% Nb, and solid solution Nb about 20% beta and -Zr phase becomes a mixed each other needle-like organization. 溶接加工後の冷却速度は一義的に定まらないが、いずれの場合も残留歪の多い針状組織となり、β− Cooling rate after welding is not determined uniquely, in any case become more acicular structure of residual strain, beta-
Zr相が生成する傾向がある。 There is a tendency for Zr phase is generated.

【0007】本発明によると、溶接加工後に冷間加工を施し、続いて相変態熱処理を施すので、残留歪を緩和し、またβ−Zr相をα−Zr相およびβ−Nb相すなわち耐食性の良好な相に変態させることができるので、 [0007] According to the present invention, subjected to cold working after welding, followed since the performing phase transformation heat treatment, relieve residual strain and the beta-Zr phase alpha-Zr phase and beta-Nb phase i.e. corrosion resistance it is possible to transform a good phase,
溶接部の耐食性を向上させることができる。 It is possible to improve the corrosion resistance of the weld. この際、冷間加工率が5%未満では加工歪が過少であるため、残留歪の緩和が生じ難く、また相変態が不足し、耐食性の回復が少ない。 In this case, since cold working ratio is less than 5% is a working strain is too small, hardly occurs relaxation of residual strain, also the phase transformation is insufficient, less corrosion resistance of the recovery. 一方、溶接部に生じた針状組織は冷間加工性が悪いため、30%を越えると加工中に割れが生じ易く、加工が困難となる。 On the other hand, acicular structure generated in weld has poor cold workability, easily cracked during processing exceeds 30%, processing becomes difficult. また、熱処理温度が520℃未満では相変態が不十分で、耐食性が不足する。 Moreover, insufficient phase transformation is less than the heat treatment temperature is 520 ° C., the corrosion resistance is insufficient. 一方、6 On the other hand, 6
00℃を越えると、残留歪を緩和することができるが、 It exceeds 00 ° C., but can be alleviated residual strain,
β−Zr相の生成が助長され、却って耐食性が低下する。 Generation of beta-Zr phase is promoted, rather corrosion resistance decreases. 尚、熱処理時間は、部材の大きさや冷間加工率の程度により異なるが、通常、30分〜10時間程度とされる。 The heat treatment time varies depending on the degree of size and cold working ratio of the member, usually about 30 minutes to 10 hours.

【0008】 [0008]

【実施例】(α+β)型Zr−2.5wt%Nb合金を溶製し、得られたインゴットを鍛造、圧延して板厚2.5 EXAMPLES The (alpha + beta) type Zr-2.5 wt% Nb alloy was melted, forged and the resulting ingot, plate thickness and rolled 2.5
mmの板材を製造し、これより150mm幅×200mm長の板片を採取した。 Manufactured mm plate material was collected now to 150mm width × 200 mm length of the plate pieces. この板片を突き合わせた後、エレクトロンビーム溶接して、供試材を得た。 After butting the plate piece, and electron beam welding, to obtain a test material.

【0009】この供試材に対して、表1及び表2の冷間加工条件で最大加工率(板厚減少率)40%の冷間圧延を行った後、同表に示す種々の温度で5h保持後、放冷した。 [0009] For this test materials, after the maximum machining rate (thickness reduction ratio) of 40% cold rolling in cold working conditions in Table 1 and Table 2, at various temperatures shown in the Table after 5h retention, and allowed to cool. このような処理を行った供試材から試料を採取して、400℃、105kgf/cm Such process samples were taken from the test materials was performed, 400 ℃, 105kgf / cm 2の水蒸気中で腐食試験を行い、72hr保持後の酸化膜厚さ(μm)を測定した。 Carried out corrosion tests in 2 in water vapor was measured oxide film thickness after 72hr hold ([mu] m). 耐食性は酸化膜厚さで評価することとし、酸化膜厚さ3μm未満をレベル1、同値以上をレベル2とし、レベル1では耐食性が良好であると判定した。 Corrosion resistance and be evaluated in oxide thickness, level 1 less than oxide thickness 3 [mu] m, more than equivalent to the level 2, the corrosion resistance in the level 1 is determined to be good. それらの結果を冷間加工時の欠陥の有無と共に表1及び表2に示す。 The results along with the presence or absence of a defect at the time of cold working are shown in Table 1 and Table 2. 尚、試料数は2点であり、同表のデータは平均値である。 The number of samples is two points, the data of the table are average values.

【0010】 [0010]

【表1】 [Table 1]

【0011】 [0011]

【表2】 [Table 2]

【0012】表1及び表2より、実施例にかかる試料では、冷間加工時に欠陥の発生もなく、耐食性も良好であることが分かる。 [0012] From Table 1 and Table 2, the samples according to Example, no generation of defects during cold working, it can be seen the corrosion resistance is good. 特に、冷間加工率が10%以上で、熱処理温度が550〜600℃では酸化膜厚さが2μm未満であり、耐食性が極めて良好である。 In particular, by cold working ratio of 10% or more, the oxide film thickness of the heat treatment temperature is 550 to 600 ° C. of less than 2 [mu] m, the corrosion resistance is very good. また、同表より、熱処理温度550℃のデータを抽出して、冷間加工率と酸化膜厚さとの関係を調べた。 Further, from the table, it extracts the data of the heat treatment temperature 550 ° C., was examined the relationship between the cold working ratio and the oxide film thickness. その結果を図1に示す。 The results are shown in Figure 1. これより、本発明の冷間加工率の下限である5%、 From this, 5% which is the lower limit of the cold working ratio of the present invention,
好ましくは10%以上で耐食性が大幅に向上し、40% Preferably the corrosion resistance is greatly improved by more than 10%, 40%
まで変化しないことが分かる。 It can be seen that does not change up. もっとも、30%を越えると、加工性に問題がある。 However, if it exceeds 30%, there is a problem in workability.

【0013】更にまた、同表より、冷間加工率が10% [0013] Furthermore, from the table, the cold working ratio is 10%
のデータを抽出して、熱処理温度と酸化膜厚さとの関係を調べた。 Extracts data to examine the relationship between the oxide film thickness and heat treatment temperature. その結果を図2に示す。 The results are shown in Figure 2. これより、本発明範囲である520℃好ましくは550℃以上、600℃以下で優れた耐食性の改善作用が得られることが分かる。 From this, 520 ° C. preferably present invention range 550 ° C. or higher, is can be seen that to obtain improvement effects of excellent corrosion resistance at 600 ° C. or less.

【0014】 [0014]

【発明の効果】以上説明した通り、本発明のジルコニウム合金溶接部材の製造方法は、(α+β)型ジルコニウム合金に対して溶接加工を行った後、5〜30%の加工率で冷間加工を行い、次いで520〜600℃の熱処理を行うので、溶接部の残留歪を緩和し、またβ−Zr相をα−Zr相およびβ−Nb相に変態させることができ、これにより溶接部の耐食性を大幅に向上させることができる。 As described above, according to the present invention, a manufacturing method of zirconium alloy welding member of the present invention, the weld after machining was performed, cold working with 5-30% of working ratio relative to (alpha + beta) type zirconium alloy performed, then since the thermal treatment of 520 to 600 ° C., to relax the residual strain of the welded portion, also beta-Zr phase can be transformed into alpha-Zr phase and beta-Nb-phase, thereby the corrosion resistance of the weld it is possible to greatly improve.

【図面の簡単な説明】 BRIEF DESCRIPTION OF THE DRAWINGS

【図1】(α+β)型ジルコニウム合金溶接部材の冷間加工率と耐食性との関係を示すグラフである。 1 is a graph showing the relationship between the cold working ratio and corrosion resistance (alpha + beta) type zirconium alloy welding member.

【図2】(α+β)型ジルコニウム合金溶接部材の熱処理温度と耐食性との関係を示すグラフである。 2 is a graph showing the relationship between the heat treatment temperature and the corrosion resistance (alpha + beta) type zirconium alloy welding member.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 安部 勝洋 兵庫県加古川市尾上町池田字池田開拓2222 −1 株式会社神戸製鋼所加古川研究地区 内 ────────────────────────────────────────────────── ─── of the front page continued (72) inventor Katsuhiro Abe Hyogo Prefecture Kakogawa Onoechoikeda shaped Ikeda pioneer 2222 -1 Kobe Steel, Ltd. Kakogawa research in the district

Claims (1)

    【特許請求の範囲】 [The claims]
  1. 【請求項1】 (α+β)型ジルコニウム合金に対して溶接加工を行った後、加工率が5〜30%の冷間加工を行い、次いで520〜600℃の熱処理を行うことを特徴とするジルコニウム合金溶接部材の製造方法。 1. A after welding against (alpha + beta) type zirconium alloy, working ratio performs processing between 5-30% cold, then and performing the heat treatment at 520-600 ° C. Zirconium method for producing alloy welding member.
JP32037693A 1993-12-20 1993-12-20 Production of zirconium alloy welded member Pending JPH07173587A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP32037693A JPH07173587A (en) 1993-12-20 1993-12-20 Production of zirconium alloy welded member

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP32037693A JPH07173587A (en) 1993-12-20 1993-12-20 Production of zirconium alloy welded member

Publications (1)

Publication Number Publication Date
JPH07173587A true JPH07173587A (en) 1995-07-11

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Family Applications (1)

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JP32037693A Pending JPH07173587A (en) 1993-12-20 1993-12-20 Production of zirconium alloy welded member

Country Status (1)

Country Link
JP (1) JPH07173587A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100597310B1 (en) * 2004-11-26 2006-07-06 한전원자력연료 주식회사 Manufacturing method of CANDU fuel appendages by using Zr-Be alloyed strap and Fusion Brazing Process by using Zr-Be alloyed strap
CN102816981A (en) * 2012-08-13 2012-12-12 燕山大学 Preparation method for zirconium-niobium alloy having gradient microstructure
US8795441B2 (en) * 2006-04-26 2014-08-05 Smith & Nephew, Inc. Reworking of surface oxidized and nitrided components
US9764061B2 (en) 2004-09-16 2017-09-19 Smith & Nephew, Inc. Method of providing a zirconium surface and resulting product

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9764061B2 (en) 2004-09-16 2017-09-19 Smith & Nephew, Inc. Method of providing a zirconium surface and resulting product
KR100597310B1 (en) * 2004-11-26 2006-07-06 한전원자력연료 주식회사 Manufacturing method of CANDU fuel appendages by using Zr-Be alloyed strap and Fusion Brazing Process by using Zr-Be alloyed strap
US8795441B2 (en) * 2006-04-26 2014-08-05 Smith & Nephew, Inc. Reworking of surface oxidized and nitrided components
CN102816981A (en) * 2012-08-13 2012-12-12 燕山大学 Preparation method for zirconium-niobium alloy having gradient microstructure

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