JPS61186195A - Welding method of different material joint - Google Patents

Abstract

PURPOSE:To improve the strength characteristic of a weld metal and to prevent the cracking thereof by welding different metals such as stainless steel, carbon steel and low alloy steel by using a low carbon welding material contg. specific wt% of Cr, Ni, Nb, Ti, Al, etc. CONSTITUTION:0.5-4% Ni, 1-8% Cr, 0.02-2% Si, 0.02-2% Mn, 0.05-4% Nb+Ta, 0.05-0.4% Al, <=1.5% Ti, <=2% Mo and <=0.06% C are incorporated as the components of the welding material into said material and the balance is composed of Fe. A base metal 1 which is stainless steel or special alloy such as HK-40 and the carbon steel or low alloy metal 2 are welded by using such welding material to form the weld metal 3. Since the content of Cr of the weld metal 3 decreases, the decarburization and carburization near the low alloy steel side bond are decreased, the hardness change is decreased and the difference in the coefft. of thermal expansion is lessened as well. The cracking is thus prevented and the creep strength characteristic, etc. are improved.

Description

【発明の詳細な説明】 （発明の利用分野） この発明は炭ＲＩＩまたは低合金鋼の母材とステンレス
鋼または特殊合金の母材よりなる異種材料溶接継手の溶
接方法の改良にかかる。DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to an improvement in a welding method for a dissimilar material welded joint consisting of a carbon RII or low alloy steel base material and a stainless steel or special alloy base material.

（従来技術） 加熱炉、塔、タンク及び熱交換器やボイラ等の高温機器
プラントはプロセス条件によって一般の炭素鋼のほかに
低合金鋼或いは耐熱、耐食、低温用のステンレス鋼や、
ＨＫ、４０の如き特殊合金が使用され、必然的に各種の
異種材料継手（以下異材継手という）の溶接が行われて
いる。(Prior art) High-temperature equipment plants such as heating furnaces, towers, tanks, heat exchangers, and boilers are made of low-alloy steel, heat-resistant, corrosion-resistant, and low-temperature stainless steel, in addition to general carbon steel, depending on the process conditions.
Special alloys such as HK and 40 are used, and various types of dissimilar material joints (hereinafter referred to as dissimilar material joints) are necessarily welded.

ところで従来このような炭素鋼または低合金鋼とステン
レス鋼または特殊合金との異材継手の溶接にはオーステ
ナイト系ステンレス鋼溶接材料あるいはインコネル系の
溶接材料を用いることが通例である。Conventionally, it has been customary to use an austenitic stainless steel welding material or an Inconel welding material for welding a dissimilar metal joint between carbon steel or low alloy steel and stainless steel or a special alloy.

（発明が解決しようとする問題点） しかしながら従来方法では溶接割れの発生を防止し、必
要な曲げ延性を得るためＣｒおよびＮｉを多量に含む溶
接材料を必要とするので溶接材料のコストが高くつくと
か、高温機器プラントの異材継手部では低合金鋼母材の
溶接ポンド部近傍が脱炭する一方、オーステナイト系溶
接金属に浸炭層が生成して強度が不連続になり、特にこ
の脱炭部のクリープラブチャ強度が低下する。(Problem to be solved by the invention) However, the conventional method requires welding materials containing large amounts of Cr and Ni in order to prevent weld cracking and obtain the necessary bending ductility, which increases the cost of welding materials. For example, in dissimilar metal joints in high-temperature equipment plants, the vicinity of the weld pound of the low-alloy steel base metal decarburizes, while a carburized layer forms in the austenitic weld metal, resulting in discontinuous strength, especially in this decarburized part. Creep love strength decreases.

またプラントの運転開始と停止との繰り返しにより低合
金鋼（例えば１．２５　Ｃｒ−０，５Ｍｏ鋼）母材と例
えばＤ３０９を用いた溶接金属との熱膨張係数の差に基
づいて溶接金属の低合金鋼側ボンド部近傍において熱疲
労破断を起こすようになる等の問題があり、種々対策が
検討されている。In addition, due to the repeated start and stop of plant operation, the weld metal becomes lower due to the difference in thermal expansion coefficient between the base material of low-alloy steel (e.g., 1.25 Cr-0,5Mo steel) and the weld metal using, for example, D309. There are problems such as thermal fatigue rupture occurring near the bond part on the alloy steel side, and various countermeasures are being considered.

このうち継手性能の改善については例えば特開昭５５−
１００８９１号公報に示されるようにオーステナイトス
テンレス鋼とＣｒ−Ｍｏフエライ日岡とをオーステナイ
ト系ステンレス溶接材料を使用して溶接し、溶接金属と
Ｃｒ−Ｍｏフェライト鋼との境界部を更にインコネル系
の溶接材料を用いて溶接する方法、或いは特開昭５５−
１００８９２号公報の発明の詳細な説明の欄に開示され
ているようにオーステナイトステンレス鋼とＣｒ−Ｍ　
ｏ　鋼との間に例えばインコネルの如き中間材を挟み、
それぞれの継手を拡散接合等の直接溶接或いは溶接材料
を用いて溶融溶接法で溶接することが提案されている。Regarding the improvement of joint performance, for example, JP-A-55-
As shown in Publication No. 100891, austenitic stainless steel and Cr-Mo ferritic steel are welded using an austenitic stainless steel welding material, and the boundary between the weld metal and the Cr-Mo ferritic steel is further welded with Inconel-based welding material. Method of welding using materials or JP-A-55-
Austenitic stainless steel and Cr-M as disclosed in the detailed description of the invention section of Publication No.
o Sandwiching an intermediate material such as Inconel between the steel and
It has been proposed to weld each joint by direct welding such as diffusion bonding or by fusion welding using a welding material.

これらはいずれも異材継手部の隣合った母材或いは溶接
金属の熱膨張係数の差を小さくすように工夫されたもの
で、高温長時間使用における継手性能の向上には効果が
認められるが、溶接金属と低強度側母材との境界部をイ
ンコネルで再溶接するので継手の溶接回数が多くなると
か、継手個所が多くなる等の実用上の問題がある上に、
溶接コストが高いことに対する改善がなされていない。All of these are designed to reduce the difference in thermal expansion coefficients between adjacent base materials or weld metals in dissimilar metal joints, and are effective in improving joint performance during long-term use at high temperatures. Since the boundary between the weld metal and the base metal on the lower strength side is re-welded with Inconel, there are practical problems such as the number of welds for the joint increases and the number of joints increases.
No improvements have been made to address the high welding costs.

本発明は上記の如き問題点を解決し、安価な溶接材料を
用いながら、溶接時の割れ発生を防止すると共に、継手
部の曲げ、引張性能を改善し、或いは低合金鋼とステン
レス鋼または低合金鋼と特殊合金との組合せ継手部のク
リープラブチャ強度を強化し、更に溶接金属の炭素鋼ま
たは低合金鋼側のポンド部近傍の熱疲労破断を防止する
溶接方法を提供することを目的としている。The present invention solves the above-mentioned problems, uses inexpensive welding materials, prevents cracking during welding, improves the bending and tensile performance of the joint, or uses low-alloy steel, stainless steel, or low-alloy steel. The purpose of the present invention is to provide a welding method that strengthens the creep-lubrium strength of a joint made of a combination of alloy steel and special alloy, and further prevents thermal fatigue fracture in the vicinity of the pound part on the carbon steel or low alloy steel side of the weld metal. There is.

（問題点を解決するための手段） 上記の目的を達成するため本発明は、 異種材料溶接継手の溶接方法において Ｃ０．０６％以下 Ｓｉ０．０２〜２％、 Ｍｎ　　０．０２〜２％、 Ｃｒ　　１〜８％、 Ｍｏ２％以下、 Ｎｉ０．５〜４％、 Ｎｂ＋Ｔａ　　　０．０５〜４％、 Ａ１０．０５〜０．４％、 Ｔｉ１．５％以下、 残部　鉄および不純物 よりなる低炭素溶接材料を用いることを特徴とする異材
継手の溶接方法に係る。(Means for Solving the Problems) In order to achieve the above object, the present invention provides a welding method for a welded joint of dissimilar materials, in which C0.06% or less, Si0.02-2%, Mn 0.02-2%, Cr. Low carbon welding material consisting of 1 to 8%, Mo 2% or less, Ni 0.5 to 4%, Nb + Ta 0.05 to 4%, A 10.05 to 0.4%, Ti 1.5% or less, balance iron and impurities. The present invention relates to a welding method for dissimilar metal joints.

なお本発明において異材継手とは継手の一方の母材が炭
素鋼または例えば１．２５Ｃｒ−０，５Ｍ。In the present invention, a dissimilar metal joint means that one base material of the joint is carbon steel or, for example, 1.25Cr-0.5M.

鋼の如き低合金鋼であり、他方の母材がステンレス鋼ま
たは特殊合金（ＨＫ−４０等の高合金鋼を含む）である
異種材料の組合せよりなる溶接継手をいうこととする。It refers to a welded joint made of a combination of different materials, one of which is a low alloy steel such as steel, and the other base material is stainless steel or a special alloy (including high alloy steel such as HK-40).

ところで各種のステンレス鋼と炭素鋼または低合金鋼、
例えば５ＵＳ３０４と１．２５　Ｃｒ　−０，５Ｍｏま
たは５Ｍ４１との溶接継手部における欠陥発生位置は強
度の小さい低合金鋼または炭素鋼母材部であるから溶接
金属を強化しても溶接継手部の強化にはならず、従って
溶接金属の性能は低強度側母材の炭素鋼または低合金鋼
の性能を満足すれば足りることになる。しかしながら市
販の炭素鋼または１．２５　Ｃｒ　−０，５Ｍ　ｏ横用
の熔接材料Ｄ４３０１またはＤＴ２３１５を用いて溶接
したのでは溶接金属がマルテンサイト組織となって硬化
し、溶接時に割れを発生したり、曲げ延性が低下して曲
げ試験で不合格になったりする。　したがって第３図に
示すように例えばオーステナイトステンレス鋼（ＳＵＳ
３０４）１１と低合金鋼（１，２５Ｃｒ−０，５Ｍｏ）
　　１２とを溶接する場合、オーステナイト系の溶接材
料Ｄ３０９　（２４Ｃｒ・１３Ｎｉ）或いはインコネル
系溶接材料ＤＮｉＣｒＦｅ２　（１６Ｃｒ・６８Ｎｉ）
等を用いて溶接するのが通例である。By the way, various types of stainless steel and carbon steel or low alloy steel,
For example, in a welded joint between 5US304 and 1.25Cr-0,5Mo or 5M41, defects occur in the low-strength low-alloy steel or carbon steel base metal, so even if the weld metal is strengthened, the welded joint cannot be strengthened. Therefore, it is sufficient that the performance of the weld metal satisfies the performance of the low-strength base material, carbon steel or low alloy steel. However, if welding is carried out using commercially available carbon steel or 1.25 Cr-0,5Mo horizontal welding materials D4301 or DT2315, the weld metal becomes a martensitic structure and hardens, causing cracks to occur during welding. Bending ductility decreases and the bending test fails. Therefore, as shown in Figure 3, for example, austenitic stainless steel (SUS)
304) 11 and low alloy steel (1,25Cr-0,5Mo)
When welding with 12, use austenitic welding material D309 (24Cr/13Ni) or Inconel welding material DNiCrFe2 (16Cr/68Ni).
It is customary to weld using a similar method.

この場合Ｄ３０９を用いた異材継手溶接部を例にとると
、長時間高温使用によって溶接金属１３の低強度母材側
ボンド部１４近傍には浸炭層１５が生成し、低強度母材
１２には税炭層１６が生成して、第４図に示すようにこ
の部分に著しい硬さの相違が生じ、これに基づいて冶金
的なノツチとなって曲げ引張等の性能が低下する一方、
２０〜４００℃における熱膨張係数（μｍ　／　ｍ　／
　’Ｃ）はオーステナイトステンレス鋼では１７或いは
溶接金属では１８であるのに対し、低合金鋼のそれが１
３．５であるから、繰り返し加熱を受けると膨張収縮の
差によって冶金的ノツチ部分において熱疲労破断するお
それが大きい。In this case, taking a dissimilar metal joint weld using D309 as an example, a carburized layer 15 is formed near the bond part 14 on the low-strength base metal side of the weld metal 13 due to long-term high-temperature use, and the low-strength base metal 12 is A coal layer 16 is formed, and as shown in FIG. 4, a significant difference in hardness occurs in this part, which causes a metallurgical notch and deteriorates performance such as bending and tensile strength.
Thermal expansion coefficient (μm/m/
'C) is 17 for austenitic stainless steel or 18 for weld metal, while that for low alloy steel is 1.
3.5, there is a strong possibility that thermal fatigue fracture will occur at the metallurgical notch due to the difference in expansion and contraction when repeatedly heated.

本発明の溶接方法に従って第１図に示すようにオーステ
ナイト、フェライト、あるいはマルテンサイトステンレ
ス鋼またはＨＫ−４０等の特殊合金母材１と炭素鋼また
は１．２５　Ｃｒ　−０，５Ｍ　ｏ鋼やＭ　ｎ　−Ｍ　
ｏ鋼等の低合金！ＩＩ　２とを溶接金属３で溶接すれば
溶接時の割れの発生を防止できると共に、曲げ延性や引
張性能の優れた溶接金属を得ることができる。According to the welding method of the present invention, as shown in FIG. 1, a special alloy base material 1 such as austenitic, ferritic, or martensitic stainless steel or HK-40 and carbon steel, 1.25 Cr-0,5 Mo steel, or M n -M
Low alloys such as o steel! By welding II 2 with weld metal 3, it is possible to prevent cracks from occurring during welding and to obtain a weld metal with excellent bending ductility and tensile performance.

また溶接材料、従って溶接金属のＣｒ量が従来方法に比
べて少ないので、この継手部が高温で長時間使用されて
も低合金鋼側ボンド部４近傍においてクロム炭化物に起
因する脱炭及び溶接金属への浸炭が起こる問題が少なく
、第２図に示すように溶接金属を挟んで硬度の変化も僅
少であり、また従来法の溶接金属に比して炭素鋼または
低合金鋼母材との強度差が小さく、冶金的性質の差も小
さくなる。In addition, since the amount of Cr in the welding material, and therefore the weld metal, is lower than in the conventional method, even if this joint is used at high temperatures for a long time, decarburization due to chromium carbide and weld metal in the vicinity of the bond part 4 on the low alloy steel side will occur. There is less problem of carburization, and as shown in Figure 2, there is little change in hardness across the weld metal, and the strength is lower than that of the carbon steel or low alloy steel base material compared to the weld metal of the conventional method. The difference is small, and the difference in metallurgical properties is also small.

また低強度側の低合金鋼母材の熱膨張係数は゛　　１３
〜１４　（μｍ／ｍ７℃）、溶接金属のそれは１３で、
その差も小さくなっている。したがってクリープラブチ
ャおよび耐熱疲労特性が改善される。In addition, the thermal expansion coefficient of the low-alloy steel base material on the low strength side is ゛ 13
~14 (μm/m7℃), that of weld metal is 13,
The difference is also getting smaller. Creep love and thermal fatigue properties are therefore improved.

本発明は炭素鋼または低合金鋼とステンレス鋼またはＨ
Ｋ４０等の特殊合金の異材継手の溶接には１〜８％Ｃｒ
、０．５〜４％Ｎｉを主成分とする溶接材料を用いるこ
とを特徴とした溶接方法である。なおＣを固定して溶接
時の割れ発生を防止し、溶接金属の延性を改善する目的
でＮｂ、Ｔａ。The present invention combines carbon steel or low alloy steel with stainless steel or H
1 to 8% Cr for welding dissimilar metal joints of special alloys such as K40.
, is a welding method characterized by using a welding material containing 0.5 to 4% Ni as a main component. Note that Nb and Ta are used to fix C, prevent cracking during welding, and improve the ductility of the weld metal.

Ｔｉ、ＡＩを溶接材料に添加しである。Ti and AI are added to the welding material.

次に本発明に使用する溶接材料の化学成分組成の限定理
由を述べる。Next, the reason for limiting the chemical composition of the welding material used in the present invention will be described.

Ｃは溶接金属の硬さを増して溶接割れを発生しやすくす
るほか、延性を低下させるので少ない方がよいが、少な
過ぎると必要な強度が得られなくなるので０．０６％以
下とする。C increases the hardness of the weld metal, making weld cracks more likely to occur, and also reduces ductility, so it is better to have a smaller amount, but if it is too small, it will not be possible to obtain the necessary strength, so it should be 0.06% or less.

ＳｉおよびＭｎは通例脱酸剤として添加されるが、その
量が多くなると溶接金属の延性が低下するので２％以下
とし、一方０．２％以下ではその効果が認められなくな
るので下限は０．２％とする。Si and Mn are usually added as deoxidizing agents, but if the amount increases, the ductility of the weld metal will decrease, so it should be 2% or less, and if it is 0.2% or less, the effect will not be recognized, so the lower limit is 0. 2%.

ＣｒおよびＮｉは溶接金属の必要強度を得るため、また
Ｃｒは溶接割れを防止し、曲げ延性を向上させるため、
Ｎｉは衝撃値の向上のため欠くことのできない成分であ
るが、その量が多くなると溶接時に割れが発生し易くな
り、曲げ延性も低下する。またＣｒ量が多くなると高温
長時間使用によって低合金鋼母材と溶接金属のボンド部
近傍で脱炭または浸炭層が形成されるためＣｒの上限は
８％とし、溶接割れの発生防止および曲げ延性の低下を
軽減する理由で下限は１％とする。Ｎｉは同様に曲げ延
性の低下を軽減する理由で上限は４％とし、所定の強度
と衝撃値を得る必要から下限は０．５％とする。Cr and Ni are used to obtain the necessary strength of the weld metal, and Cr is used to prevent weld cracking and improve bending ductility.
Ni is an indispensable component for improving the impact value, but if its amount increases, cracks are likely to occur during welding and bending ductility also decreases. In addition, if the Cr content increases, decarburization or carburization will occur near the bond between the low-alloy steel base metal and the weld metal due to long-term use at high temperatures. The lower limit is set at 1% in order to reduce the decrease in Similarly, the upper limit of Ni is set at 4% for the reason of reducing the decrease in bending ductility, and the lower limit is set at 0.5% because it is necessary to obtain a predetermined strength and impact value.

Ｎｂ、Ｔ　ｉ、Ｔａについては次の通りである。The details of Nb, Ti, and Ta are as follows.

本発明の異材継手溶接方法に用いる溶接材料はＣ量を少
なく調整しているが、高Ｃ含有量の母材を溶接すると母
材のＣが溶接金属中に溶は込み、或いば被覆アーク溶接
棒を使用するとフランクス中のＣが溶接金属中に溶けこ
むため溶接金属の延性が低下する。従って本発明ではこ
の問題を解決するためＣと親和力の大きなＮｂ、Ｔｔ、
Ｔａを添加した溶接材料を用いて溶接し、溶接金属中の
Ｃを固定させるようにしている。しかし過剰に添加する
とかえって溶接金属の延性を低下させることになるので
Ｎｂ＋Ｔａは４％以下とし、一方０．５以下ではその効
果が認められないので下限は０．５％とする。またＴｉ
はＮｂ、Ｔａと同様な効果があるが、過剰に添加すると
溶接金属の延性および溶接作業性を悪くするので１．５
％以下とする。The welding material used in the dissimilar metal joint welding method of the present invention is adjusted to have a small amount of C, but when welding a base metal with a high C content, the C in the base metal penetrates into the weld metal, or the covered arc When a welding rod is used, carbon in the flanks dissolves into the weld metal, reducing the ductility of the weld metal. Therefore, in the present invention, in order to solve this problem, Nb, Tt, which has a large affinity with C,
Welding is performed using a welding material to which Ta is added to fix C in the weld metal. However, if added excessively, the ductility of the weld metal will be reduced, so the content of Nb+Ta should be 4% or less, while if it is 0.5 or less, no effect will be observed, so the lower limit is 0.5%. Also Ti
Although it has the same effect as Nb and Ta, if added in excess, it deteriorates the ductility of the weld metal and welding workability, so 1.5
% or less.

Ａ１は溶接時に酸素が混入して溶接金属の靭性を害する
ので、これを防止して硬化を抑え、溶接金属の延性を改
善する目的で添加するが、過剰に含有する溶接材料を用
いると固溶Ａ１の増加により溶接金属の性能が低下する
ようになるので０．４％以下とし、一方０．０５％以下
ではその効果が認められなくなるので下限は０．０５％
とする。A1 is added for the purpose of preventing oxygen from entering during welding and impairing the toughness of the weld metal, suppressing hardening, and improving the ductility of the weld metal. As the performance of the weld metal decreases due to an increase in A1, it should be set at 0.4% or less, and on the other hand, if it is below 0.05%, the effect will not be recognized, so the lower limit is 0.05%.
shall be.

Ｍｏは溶接金属の必要強度を得るために有効な成分であ
るが、その量が多くなると溶接金属の曲げ延性を低下さ
せるようになるので２％以下とする。Mo is an effective component for obtaining the necessary strength of the weld metal, but if its amount increases, the bending ductility of the weld metal decreases, so it should be kept at 2% or less.

本発明の異材継手の溶接施工法はＴＩＧ、ＭＴＧ、ＭＡ
Ｇまたは被覆アーク溶接法、サブマージアーク溶接法等
の溶接材料を使用する溶接に通用することができる。The welding methods for dissimilar metal joints of the present invention are TIG, MTG, and MA.
It can be applied to welding using welding materials such as G, coated arc welding, submerged arc welding, etc.

（試験例） 次に溶接試験結果について述べる。(Test example) Next, we will discuss the welding test results.

第１表に試験に供された母材の化学成分組成を示す。Table 1 shows the chemical composition of the base materials used in the test.

第２表に試験に供された溶接材料の化学成分組成を示す
。Table 2 shows the chemical composition of the welding materials used in the test.

第３表には第１表の母材供試材（厚さ２０ｍｍ）の組合
せ別に溶接試験を行った結果を、溶接材料別に対比して
示しである。なお溶接は第４表に示す条件で６０度Ｖ開
先継手をアーク溶接またはＴＩＧ熔接溶接って行い、第
３表の溶接方法の欄に略号ＡまたはＴで示しである。ま
た放射線透過試験ばＪｒＳＺ３０１６に従って行い、溶
接割れのあるものはＸ印で示した。曲げ試験はＪＩＳＺ
３１２２による倒曲げを行い、３．２ｍｍ以上の割れの
発生したものはＸ印とし、無欠陥のものは◎印で示しで
ある。引張試験はＪＩＳＺ３１２１により溶接継手部に
ついて行い引張強さくｋｇｆ／■ｌＩ２〉を示しである
。Table 3 shows the results of welding tests conducted for each combination of the base material samples (thickness 20 mm) in Table 1, in comparison with each welding material. The welding was performed by arc welding or TIG welding of the 60° V groove joint under the conditions shown in Table 4, and is indicated by the abbreviation A or T in the welding method column of Table 3. In addition, a radiographic test was conducted according to JrSZ3016, and those with weld cracks are marked with an X mark. Bending test is JISZ
3122, and those with cracks of 3.2 mm or more are marked with an X mark, and those with no defects are marked with a ◎ mark. A tensile test was conducted on the welded joint according to JIS Z3121, and the tensile strength is kgf/lI2>.

第１表（れ％） ＊　　Ｐ　＝０．０１〜０．０３．Ｓ＝０．０１〜０．
０２＊１　八Ｉ＝０．２２．　　Ｃ２Ｍｏ＝０．４８注
。＊Ｐ０．０２以下、Ｓ　０．０１５以下＊１　　：Ｍ
ｏ＝０．８．Ｃｕ＝０．０６、Ｃ２：Ｍｏ＝０．５＊３
　　：　Ａｌ　＝０．０９．ＴＪ　　−０，０７，Ｍｏ
　　＝０．２５＊４　　：　Ｔｉ　＝０．３．Ｃｏ　　
＝０．０１＊５　　：　Ｍｏ＝０．５．　Ｃ６＾１＝０
．２５．Ｍｏ　　＝０．２５（ａ）〜（ｅｌ　　被覆ア
ーク溶接棒 （ｆ）〜（１）ＴＩＧ熔加材 （ａｌ、（ｆｌ・・・オーステナイト系偽）、（１・・
・インコネル系 （Ｃ１、（ｈｌ−１，２５Ｃｒ−０，５Ｍｏ用（ｄｌ　
　　・・・炭素鋼用 ｔｅｌ、（１１・・・本発明に係る熔接材料第３表 第４表 第３表によれば低合金鋼のＳＣＭＶ３と５ＵＳ３０４ま
たはＨＫ４０との溶接継手を１．２５　Ｃｒｏ、　５　
Ｍ　ｏ積用の溶接材料ＤＴ２３１６或いはＥＲ８０Ｓ−
Ｇを使用して溶接した場合、放射線透過試験または曲げ
試験で割れの発生が検出されたが、本発明に係る溶接方
法ではいずれの場合も割れが認められず、ＮｉおよびＣ
ｒを多量に含有するオーステナイト系のＤ３０９、Ｙ２
Ｏ２およびＤＮｉＣｒＦｅ２を使用した場合と同様な成
績を示すことが判る。Table 1 (%) *P = 0.01-0.03. S=0.01~0.
02*1 8I=0.22. C2Mo=0.48Note. *P 0.02 or less, S 0.015 or less *1: M
o=0.8. Cu=0.06, C2:Mo=0.5*3
: Al =0.09. TJ-0,07,Mo
=0.25*4: Ti =0.3. Co
=0.01*5: Mo=0.5. C6^1=0
．． 25. Mo = 0.25 (a) ~ (el coated arc welding rod (f) ~ (1) TIG melting material (al, (fl...austenitic fake), (1...
・Inconel type (C1, (hl-1,25Cr-0,5Mo (dl
... tel for carbon steel, (11... According to Table 3, Table 4, Table 3 of welding materials according to the present invention, welded joints of low alloy steel SCMV3 and 5US304 or HK40 are 1.25 Cro, 5
Welding material for Mo load DT2316 or ER80S-
When welding using Ni and C, cracking was detected in radiographic tests or bending tests, but with the welding method according to the present invention, no cracks were observed in any case, and Ni and C
Austenitic D309, Y2 containing a large amount of r
It can be seen that the results are similar to those obtained using O2 and DNiCrFe2.

また５Ｍ４１Ａと５ＵＳ３０４．５ＵＳ４１０または５
ＵＳ４０５とを組合せた溶接継手を炭素鋼用の溶接材料
Ｄ４３０１を用いて溶接した場合には放射線透過試験お
よび曲げ試験で割れが検出されたが、本発明に係る溶接
の場合にはいずれの組合せの溶接継手部にも欠陥の発生
はみとめられなかった。Also 5M41A and 5US304.5US410 or 5
When a welded joint in combination with US405 was welded using welding material D4301 for carbon steel, cracks were detected in radiographic tests and bending tests, but in the case of welding according to the present invention, cracks were detected in both combinations. No defects were observed in the welded joints either.

溶接継手部の引張試験を行った結果破断位置はいずれも
低強度側母材で、引張強さは母材の規格強度を満足する
値であった。As a result of tensile testing of welded joints, the fracture locations were all in the base metal on the low strength side, and the tensile strength was a value that satisfied the standard strength of the base metal.

第５表は第１表の母材供試材のうちＳＣＭＶ３と５ＵＳ
３０４との異材継手を本発明に係る溶接材料（ｅｌ、（
ｉ）を用いて溶接した溶接部の５５０℃高温短時間引張
試験結果をＤ３０９熔接材料を用いた例と対比させて熱
処理別に示している。溶接は■開先を第４表に示す方法
で溶接した。試験片は径６ｍｍで試験方法はＪＩＳＧＯ
５６７によって行ヮた。いずれの試験片も破断は母材Ｓ
ＣＭＶ３において生じた。Table 5 shows SCMV3 and 5US of the base material samples in Table 1.
304 with the welding material (el, (
The results of a 550° C. high temperature short-time tensile test of welded parts welded using i) are shown for each heat treatment in comparison with an example using D309 welding material. Welding was carried out using the method shown in Table 4. The test piece has a diameter of 6 mm and the test method is JISGO.
It was done by 567. In both test pieces, the fracture occurred in the base material S.
Occurred in CMV3.

第５表の結果から本発明の方法によって溶接すれば従来
方法による場合と同等の高温強度が得られることが判る
。It can be seen from the results in Table 5 that high temperature strength equivalent to that obtained by the conventional method can be obtained by welding by the method of the present invention.

次に第１表の供試材のうちＳＣＭＶ３と５ＵＳ３０４の
組合せの異材溶接継手を本発明の方法に従って溶接材料
＋ｄ＋を用いて溶接した溶接部の試験片についてのクリ
ープラブチャー試験結果の一例を第５図には溶接のまま
、第６図には７２０℃×８０分加熱処理後についていず
れもＤ３０９で溶接した試験片の試験結果と対比して示
しである。Next, we will present an example of the results of the creep rupture test on a test piece of a welded joint of a combination of SCMV3 and 5US304 of the test materials shown in Table 1, which was welded using welding material +d+ according to the method of the present invention. FIG. 5 shows the test results as welded, and FIG. 6 shows the results after heat treatment at 720° C. for 80 minutes, in comparison with the test results of the test pieces welded with D309.

試験片は径６ｍｍで試験方法はＪＩＳＺ２２７２によっ
た。The test piece had a diameter of 6 mm, and the test method was in accordance with JIS Z2272.

図から判るように本発明の方法で溶接した場合は従来の
Ｄ３０９を使用して溶接した場合とほぼ同様な成績を示
し、むしろ長時間側では同一応力で比較すると破断する
までの時間が長くなっていることがわかる。As can be seen from the figure, when welding using the method of the present invention, the results are almost the same as when welding using conventional D309, but on the long-term side, when compared with the same stress, it takes longer to break. It can be seen that

（本発明の効果） 以上述べたように本発明の溶接方法は炭素鋼または低合
金鋼とステンレス鋼または特殊合金との異材継手の溶接
方法に係り、溶接材料のＣｒ量が８％以下であるから高
温で使用した場合に従来の溶接材料の２２〜２５　’Ａ
　Ｃｒのものと比べて低合金鋼と溶接金属のポンド部近
傍でＣｒ炭化物の生成に起因する脱炭および浸炭層の生
成が少ない。(Effects of the present invention) As described above, the welding method of the present invention relates to a welding method for dissimilar metal joints between carbon steel or low alloy steel and stainless steel or special alloy, and the Cr content of the welding material is 8% or less. Conventional welding materials when used at high temperatures from 22 to 25'A
Compared to Cr, there is less decarburization and carburized layer formation due to the formation of Cr carbides near the pound portion of low alloy steel and weld metal.

その結果クリープラブチャー強度の低下の問題が改善さ
れる。As a result, the problem of decreasing creep rupture strength is alleviated.

さらに熱膨張係数（μｍ　７ｍ　／　’Ｃ）が２２〜２
５％Ｃｒ、１２〜１４％ＮｉのＤ３０９の溶接金属の１
８に対し、本発明の溶接方法による溶接金属は約１３で
あって、炭素鋼および低合金鋼母材の１３〜１４に近似
しているため熱疲労破断のおそれが少ない等の効果があ
る。Furthermore, the thermal expansion coefficient (μm 7m/'C) is 22~2
1 of D309 weld metal with 5% Cr, 12-14% Ni
8, the weld metal obtained by the welding method of the present invention is about 13, which is similar to 13 to 14 of the base metal of carbon steel and low alloy steel, so there is an advantage that there is less risk of thermal fatigue fracture.

また本発明で使用する溶接材料はＮｉ含有量を０．５〜
４％とし、Ｃ含有量の上限を０．０６％として′／ｇ接
金属の強度と延性及び所要の衝撃値を維持し、さらにＮ
ｂ＋ＴａおよびＴｉを加え、たとえ母材或いはフラック
ス等からＣが溶接金属中に熔込むことがあっても、この
Ｃも含めて溶接金属中のＣを固定して延性の低下を防止
し、溶接継手部の性能を改善しているので高強度の母材
の異材継手を溶接しても必要強度を持った溶接継手部が
得られる。また使用する溶接材料にＡＩを添加して溶接
金属の組織を微細化することにより、溶接時の割れ発生
を防止し、溶接金属の曲げ延性の低下の改善を計ってい
るので炭素鋼または低合金鋼とステンレス鋼または特殊
合金との異材溶接継手の溶接方法として優れた成績が得
られる等実用上の効果がきわめて大きい。In addition, the welding material used in the present invention has a Ni content of 0.5 to
4% and the upper limit of C content is 0.06% to maintain the strength and ductility of the weld metal and the required impact value.
By adding b+Ta and Ti, even if C may melt into the weld metal from the base metal or flux, it fixes the C in the weld metal, including this C, and prevents a decrease in ductility, resulting in a welded joint. Since the performance of the welded joint has been improved, even when welding dissimilar metal joints made of high-strength base metals, welded joints with the necessary strength can be obtained. In addition, by adding AI to the welding materials used to refine the structure of the weld metal, we prevent the occurrence of cracks during welding and improve the reduction in bending ductility of the weld metal. The practical effects are extremely large, such as excellent results obtained as a welding method for dissimilar metal welding joints between steel and stainless steel or special alloys.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の溶接材料を使用し異材継手を溶接した
例を示す断面図、第２図は同じく硬度分布図、第３図は
従来の溶接材料を使用し溶接した例を示す断面図、第４
図は同しく硬度分布図、第５図はクリープラブチャ試験
結果（溶接の（ｉｌ）、第６図は同じく熱処理後の試験
片についての試験結果を示すグラフである。 １・・・ステンレス鋼または特殊合金母材、２・・・炭
素鋼または低合金鋼、３・・・溶接金属、４・・・低強
度材側ボンド部 出願人代理人　弁理士　鴨志１）次男 第１図 Ｋ　：／　ｌ’５’＋ノＭｌ　ｆｔ１ＩＰ′４２図 第３図 ボ・ンＩ＋かうの！！５馳ＩＬｍ 第４図Fig. 1 is a sectional view showing an example of welding a dissimilar metal joint using the welding material of the present invention, Fig. 2 is a hardness distribution diagram, and Fig. 3 is a sectional view showing an example of welding using a conventional welding material. , 4th
The figure is also a hardness distribution diagram, Figure 5 is a graph showing the results of the creep rubber test (welded (IL)), and Figure 6 is a graph showing the test results for the test piece after heat treatment. 1... Stainless steel or special alloy base material, 2... carbon steel or low alloy steel, 3... weld metal, 4... low strength material side bond department applicant's agent patent attorney Kamoshi 1) Second son Figure 1 K: / l'5'+ノMl ft1IP'42Figure 3Bon I+Kauno! ! 5.ILm Figure 4

Claims (1)

【特許請求の範囲】 １、異種材料溶接継手の溶接方法において、Ｃ０．０６
％以下 Ｓｉ０．０２〜２％、 Ｍｎ０．０２〜２％、 Ｃｒ１〜８％、 Ｍｏ２％以下、 Ｎｉ０．５〜４％、 Ｎｂ＋Ｔａ０．０５〜４％、 Ａｌ０．０５〜０．４％、 Ｔｉ１．５％以下、 残部鉄および不純物 よりなる低炭素溶接材料を用いて溶接することを特徴と
する異材継手の溶接方法 ２、異材継手の一方の母材が炭素鋼で、他方の母材がス
テンレス鋼である特許請求の範囲第１項記載の異材継手
の溶接方法 ３、異材継手の一方の母材が炭素鋼で、他方の母材が特
殊合金である特許請求の範囲第１項記載の異材継手の溶
接方法 ４、異材継手の一方の母材が低合金鋼で、他方の母材が
ステンレス鋼である特許請求の範囲第１項記載の異材継
手の溶接方法 ５、異材継手の一方の母材が低合金鋼で、他方の母材が
特殊合金である特許請求の範囲第１項記載の異材継手の
溶接方法[Claims] 1. In a welding method for a welded joint of dissimilar materials, C0.06
% or less Si0.02-2%, Mn0.02-2%, Cr1-8%, Mo2% or less, Ni0.5-4%, Nb+Ta0.05-4%, Al0.05-0.4%, Ti1. Welding method for dissimilar metal joints characterized by welding using a low carbon welding material consisting of 5% or less, balance iron and impurities 2, one base metal of the dissimilar metal joint is carbon steel and the other base metal is stainless steel A dissimilar metal joint welding method 3 according to claim 1, wherein one base material of the dissimilar metal joint is carbon steel and the other base material is a special alloy. Welding method 4 for a dissimilar metal joint according to claim 1, wherein one base metal of the dissimilar metal joint is low alloy steel and the other base metal is stainless steel. 5, One base metal of the dissimilar metal joint The method for welding a dissimilar metal joint according to claim 1, wherein the base metal is a low alloy steel and the other base metal is a special alloy.