JPH07252587A - Arc welded structure and oil pan excellent in pitting corrosion resistance - Google Patents
Arc welded structure and oil pan excellent in pitting corrosion resistanceInfo
- Publication number
- JPH07252587A JPH07252587A JP3996194A JP3996194A JPH07252587A JP H07252587 A JPH07252587 A JP H07252587A JP 3996194 A JP3996194 A JP 3996194A JP 3996194 A JP3996194 A JP 3996194A JP H07252587 A JPH07252587 A JP H07252587A
- Authority
- JP
- Japan
- Prior art keywords
- less
- welded structure
- corrosion resistance
- weld metal
- arc
- 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
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K1/00—Soldering, e.g. brazing, or unsoldering
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/16—Arc welding or cutting making use of shielding gas
- B23K9/173—Arc welding or cutting making use of shielding gas and of a consumable electrode
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Cylinder Crankcases Of Internal Combustion Engines (AREA)
- Arc Welding In General (AREA)
- Butt Welding And Welding Of Specific Article (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、自動車の足回り構造物
等に使用される耐孔あき腐食性の優れたアーク溶接構造
物およびオイルパンに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc welded structure and an oil pan having excellent corrosion resistance against perforation, which are used for undercarriage structures of automobiles.
【0002】[0002]
【従来の技術】近年、自動車の防錆能向上の対応策とし
て、種々のめっき鋼板が実用化されているが、アーム
類、メンバー部品、一部の大容量オイルパンなどのよう
にアーク溶接が施される部品では、溶接時の亜鉛蒸気に
起因するブローホールが美観および溶接継手強度を損な
うなどの問題があり、めっき鋼板が使用できない。2. Description of the Related Art In recent years, various plated steel sheets have been put into practical use as measures for improving the rust prevention performance of automobiles. However, arc welding such as arms, member parts, and some large-capacity oil pans has been put to practical use. In parts to be applied, there is a problem that blow holes due to zinc vapor at the time of welding impair the aesthetics and the strength of the welded joint, and therefore plated steel sheets cannot be used.
【0003】これらの部品では、塗膜を厚くするなどの
方法も検討されているが、自動車走行中の小石および融
雪岩塩の飛散が激しく、塗膜損傷局部より進展する孔あ
き腐食の問題は解決し得ない。For these parts, methods such as thickening the coating film have been studied, but the problem of pitting corrosion that develops locally from damage to the coating film due to the large scattering of pebbles and snow-melting salt during vehicle traveling is solved. I can't.
【0004】[0004]
【発明が解決しようとする課題】このような状況下で、
亜鉛めっきしていない原板そのものに耐食性を付与した
鋼板(耐食性鋼板)が最近になって開発され、一部実用
に供されている。しかし、耐食性鋼板を用いて構造部材
とした場合、耐食性鋼板部分の孔あき腐食は著しく抑制
され得るものの、部品組立時にアーク溶接されて生じた
溶接金属部(溶接ビード部)には耐食性の考慮が通常な
されていないことから、実使用において溶接部が選択的
に腐食し、継手部の静的強度のみならず疲労強度の著し
い低下および美観劣化などを引き起こすという弊害があ
った。Under these circumstances,
A steel plate (corrosion-resistant steel plate) in which corrosion resistance is imparted to a non-galvanized original plate itself has been recently developed and partially put into practical use. However, when a corrosion resistant steel plate is used as a structural member, perforation corrosion of the corrosion resistant steel plate part can be significantly suppressed, but the corrosion resistance must be considered for the weld metal part (weld bead part) generated by arc welding during assembly of the parts. Since this is not normally done, there is a harmful effect that the welded part is selectively corroded in actual use, and not only the static strength of the joint part but also the fatigue strength is remarkably lowered and the appearance is deteriorated.
【0005】通常、溶接ワイヤの成分は C量が高くまた
S含有量も高く、耐食性の考慮がなされていない。とり
わけ、図5に示すような、溶接ワイヤの希釈の程度が比
較的低い重ね継手部の溶接金属部では、溶接ワイヤの悪
影響が顕著になる。とくに、溶接構造のオイルパンでは
鋼板厚が約1.6mm 以下と薄いため、溶接では鋼板の溶け
込みが浅くなりがちであり、十分な溶接金属も生成でき
ない。Usually, the composition of the welding wire has a high C content and
The S content is also high, and no consideration is given to corrosion resistance. Particularly, as shown in FIG. 5, in the weld metal portion of the lap joint portion where the degree of dilution of the welding wire is relatively low, the adverse effect of the welding wire becomes remarkable. In particular, in a welded oil pan, the thickness of the steel sheet is as thin as about 1.6 mm or less, and therefore the penetration of the steel sheet tends to be shallow during welding, and sufficient weld metal cannot be produced.
【0006】したがって、このような重ね継手溶接部が
多いアーム、オイルパンなどの重要保安部品では、溶接
金属部における局所的な孔あき腐食が構造物としての信
頼性に大きな影響を及ぼすため、溶接金属部の耐孔あき
腐食性を向上させることが極めて重要となっている。Therefore, in important safety parts such as arms and oil pans where there are many lap joint welds, local pitting corrosion in the weld metal has a great influence on the reliability as a structure. It is extremely important to improve the perforation corrosion resistance of metal parts.
【0007】本発明は、上記の問題点を解決するために
なされたもので、アーク溶接構造物の場合は、溶接金属
中の C量と非金属介在物の量を抑制し、かつ耐食性を向
上させる元素を含有させることおよび溶接構造物の鋼板
の化学成分を限定することによって、また、オイルパン
の場合は、Cu系溶接ワイヤを用いてミグブレージング溶
接することによって、溶接部の耐食性を向上させ、かつ
継手強度を確保した耐孔あき腐食性の優れたアーク溶接
構造物およびオイルパンを提供することを目的とする。The present invention has been made to solve the above problems. In the case of an arc welded structure, the amount of C and the amount of non-metallic inclusions in the weld metal are suppressed and the corrosion resistance is improved. The corrosion resistance of the weld by limiting the chemical composition of the steel plate of the welded structure and by using Mig brazing welding with a Cu-based welding wire in the case of an oil pan. It is an object of the present invention to provide an arc-welded structure and an oil pan that have excellent joint resistance and excellent perforation corrosion resistance.
【0008】[0008]
【課題を解決するための手段】本発明の要旨は、アーク
溶接で溶接施工された溶接構造物であって、溶接金属の
化学成分がC:0.05%以下、P:0.03%超え0.20%以下、C
u:0.20 %超え1.00%以下を満足し、かつ溶接金属中に
硫化物系および酸化物系の非金属介在物が面積率で0.01
%以下である耐孔あき腐食性の優れたアーク溶接構造物
である。Means for Solving the Problems The gist of the present invention is a welded structure welded by arc welding, wherein the chemical composition of the weld metal is C: 0.05% or less, P: 0.03% or more and 0.20% or less, C
u: over 0.20% and 1.00% or less, and the area ratio of sulfide-based and oxide-based non-metallic inclusions is 0.01 in the weld metal.
% Or less, it is an arc welded structure having excellent puncture corrosion resistance.
【0009】溶接構造物の鋼板の化学成分が、C:0.05%
以下、P:0.03%超え0.20%以下、Cu:0.20 %超え1.00%
以下、Si:1.0%以下、Mn:0.10 %超え1.50%以下、 S:
0.005%以下、Al:0.01 %超え0.06%以下である耐孔あ
き腐食性の優れたアーク溶接構造物である。The chemical composition of the steel plate of the welded structure is C: 0.05%
Below, P: 0.03% over 0.20%, Cu: 0.20% over 1.00%
Below, Si: 1.0% or less, Mn: 0.10% to 1.50% or less, S:
It is an arc welded structure with excellent puncture corrosion resistance, with 0.005% or less and Al: more than 0.01% and 0.06% or less.
【0010】溶接構造物の鋼板の化学成分として、さら
にNi、Nb、Ti、V 、Cr、Mo、Zrの内から選んだ少なくと
も1種以上を0.3 %以下含む耐孔あき腐食性の優れたア
ーク溶接構造物である。An arc excellent in perforation corrosion resistance containing 0.3% or less of at least one selected from Ni, Nb, Ti, V, Cr, Mo and Zr as a chemical component of the steel plate of the welded structure. It is a welded structure.
【0011】溶接構造物の鋼板の化学成分として、さら
にCaおよび/またはREMを0.0050%以下含む耐孔あき
腐食性の優れたアーク溶接構造物である。An arc-welded structure excellent in perforation-corrosion resistance, further containing 0.0050% or less of Ca and / or REM as a chemical component of the steel plate of the welded structure.
【0012】Fe:0.2%以下、Si:2.0〜6.0 %を含有する
Cu系溶接ワイヤを用いてミグブレージング溶接された複
数の槽からなる鋼板製のオイルパンであって、溶接金属
内に混在するFe系の分散相の面積率が 6%以下である耐
孔あき腐食性の優れた鋼板製オイルパンである。Fe: 0.2% or less, Si: 2.0 to 6.0%
This is an oil pan made of steel plate that consists of multiple tanks that are Mig-Brazed welded using Cu-based welding wire, and the area ratio of the Fe-based dispersed phase mixed in the weld metal is 6% or less. A steel plate oil pan with excellent properties.
【0013】[0013]
【作用】以下に、アーク溶接構造物の溶接金属の化学成
分の限定理由について説明する。C は重ね継手アーク溶
接部の溶接金属中の含有量が0.05%を超えると、溶接金
属中でのセメンタイトの生成が顕著になり、このセメン
タイトがカソードとなり腐食を助長する。したがって、
溶接金属中のC 含有量は0.05%以下とする。The reason for limiting the chemical composition of the weld metal of the arc welded structure will be described below. When the content of C in the weld metal of the lap joint arc weld exceeds 0.05%, the formation of cementite in the weld metal becomes remarkable, and this cementite becomes a cathode and promotes corrosion. Therefore,
The C content in the weld metal should be 0.05% or less.
【0014】P は、とくにCuとの共存下で塩化物が付着
するような環境下での孔食を著しく低減する効果があ
る。重ね継手アーク溶接部の溶接金属中のP 含有量が0.
03%以下ではその効果は認められず、0.20%を超えると
その効果は飽和し逆に溶接割れなどの弊害が生じる。し
たがって、溶接金属中のP 含有量は0.03%超え0.20%以
下とする。P has an effect of remarkably reducing pitting corrosion particularly in an environment where chloride is attached in the presence of Cu. The P content in the weld metal of the lap joint arc weld is 0.
If it is less than 03%, the effect is not recognized, and if it exceeds 0.20%, the effect is saturated, and adverse effects such as weld cracking occur. Therefore, the P content in the weld metal should be more than 0.03% and 0.20% or less.
【0015】Cuは重ね継手アーク溶接部の溶接金属中の
P との共存下で防食効果のある皮膜の形成を促進する効
果を発揮する。この皮膜は微細で緻密な腐食の進行を抑
制する非晶質の有効な錆の成長を確かなものにする。湿
潤と乾燥の繰り返しの腐食環境のもとでは、溶接金属中
のCu含有量が0.20%以下ではその効果は認められず、1.
00%を超えるとその効果は飽和し逆に溶接割れなどの弊
害が生じる。したがって、溶接金属中のCu含有量は0.20
%超え1.00%以下とする。Cu is contained in the weld metal of the lap joint arc weld.
When coexisting with P, it exerts an effect of promoting the formation of a film having an anticorrosion effect. This film ensures the growth of amorphous and effective rust that suppresses the progress of fine and dense corrosion. Under the corrosive environment of repeated wet and dry, the effect is not recognized when the Cu content in the weld metal is 0.20% or less, 1.
If it exceeds 00%, the effect is saturated, and adverse effects such as weld cracking occur. Therefore, the Cu content in the weld metal is 0.20
% Over 1.00%.
【0016】つぎに、アーク溶接構造物の鋼板の化学成
分の限定理由について説明する。C 、P 、Cuは、アーク
溶接時の鋼板の溶接金属への溶け込みによって、溶接金
属の特性を損なうことのないように、鋼板中のC 、P 、
Cu含有量は溶接金属の含有量に合わせた。Next, the reasons for limiting the chemical composition of the steel plate of the arc welded structure will be explained. C, P, and Cu are C, P, and Cu in the steel sheet so as not to impair the characteristics of the weld metal due to the melting of the steel sheet into the weld metal during arc welding.
The Cu content was adjusted to the weld metal content.
【0017】Siは固溶強化によって強度と延性を向上さ
せる好ましい元素である。しかし、必要以上に添加する
と溶接性が劣化する。したがって、鋼板中のSi含有量は
1.0%以下とする。Si is a preferable element that improves strength and ductility by solid solution strengthening. However, if added more than necessary, the weldability deteriorates. Therefore, the Si content in the steel sheet is
1.0% or less.
【0018】Mnは強度と延性の上昇に有効な元素である
が、0.10%以下ではその効果は十分得られず、1.5 %を
超えると熱延鋼板中のマルテンサイトやベイナイトの混
入量が増し加工性を劣化させる。したがって、鋼板中の
Mn含有量は0.10%超え1.5 %以下とする。Mn is an element effective for increasing strength and ductility, but if it is less than 0.10%, its effect is not sufficiently obtained, and if it exceeds 1.5%, the content of martensite and bainite in the hot-rolled steel sheet increases and the workability increases. Deteriorates sex. Therefore, the
Mn content should be more than 0.10% and less than 1.5%.
【0019】S は含有量が低いほど好ましいが、所望の
溶接性、加工性を確保するためには0.005 %以下に抑え
る必要がある。したがって、鋼板中のS 含有量は0.005
%以下とする。The lower the content of S, the more preferable, but it is necessary to suppress it to 0.005% or less in order to secure desired weldability and workability. Therefore, the S content in the steel sheet is 0.005
% Or less.
【0020】Alは脱酸剤として0.01%超えの添加が必要
であるが、0.06%を超えて添加すると鋼板の清浄度を劣
化させる。したがって、鋼板中のAl含有量は0.01%超え
0.06%以下とする。Al needs to be added as a deoxidizer in an amount of more than 0.01%, but if it is added in an amount of more than 0.06%, the cleanliness of the steel sheet is deteriorated. Therefore, the Al content in the steel sheet exceeds 0.01%
0.06% or less.
【0021】NiはCu添加鋼の熱間割れを防止するために
必要な元素であり、本発明では0.3%以下の添加を行
う。したがって、鋼板中のNi含有量は0.3 %以下とす
る。Ni is an element necessary for preventing hot cracking of Cu-added steel. In the present invention, Ni is added in an amount of 0.3% or less. Therefore, the Ni content in the steel sheet should be 0.3% or less.
【0022】Nb、Ti、V 、CrおよびMoは鋼板の強度と靱
性・延性を確保するために必要な元素であるが、添加量
が0.3 %を超えるとその効果は飽和するだけでなく、溶
接性を著しく劣化させる。したがって、鋼板中のNb、T
i、V 、CrおよびMo含有量は0.3 %以下とする。Nb, Ti, V, Cr and Mo are elements necessary for securing the strength, toughness and ductility of the steel sheet, but if the addition amount exceeds 0.3%, the effect is not only saturated but also the welding Remarkably deteriorates the sex. Therefore, Nb, T in the steel plate
The i, V, Cr and Mo contents should be 0.3% or less.
【0023】Zr、CaおよびREMは介在物の形状制御に
有効な元素であり、適正な量の添加で冷間加工性を改善
することができる。しかし、過度に添加すると鋼中の非
金属介在物が多くなり、逆に冷間加工性を劣化させる。
したがって、鋼板中のZr含有量は0.3 %以下、Caおよび
REM含有量は0.0050%以下とする。Zr, Ca and REM are effective elements for controlling the shape of inclusions, and cold workability can be improved by adding an appropriate amount. However, if added excessively, the amount of non-metallic inclusions in the steel increases, and conversely the cold workability deteriorates.
Therefore, the Zr content in the steel sheet is 0.3% or less, and the Ca and REM contents are 0.0050% or less.
【0024】つぎに、アーク溶接構造物の溶接金属中の
硫化物系および酸化物系の非金属介在物の限定理由につ
いて説明する。発明者らは、溶接金属の耐食性に及ぼす
非金属介在物の影響を調査するために、上記C 、P 、Cu
の限定範囲の溶接金属について腐食試験を行った。腐食
試験は(50℃、湿度85%、11h )→(50℃、湿度30%、
3h)→(20℃、湿度60%、5h)を1サイクルとして 120
サイクル実施し、その後、溶接金属の孔あき腐食深さを
測定した。その結果を図1に示す。なお、供試した溶接
金属の厚さは 2.9mmである。Next, the reasons for limiting the sulfide-based and oxide-based nonmetallic inclusions in the weld metal of the arc welded structure will be described. In order to investigate the influence of non-metallic inclusions on the corrosion resistance of weld metal, the inventors of the present invention described above C, P, Cu.
Corrosion tests were performed on weld metal in a limited range of. Corrosion test (50 ℃, humidity 85%, 11h) → (50 ℃, humidity 30%,
3h) → (20 ° C, humidity 60%, 5h) as one cycle 120
After carrying out a cycle, the perforated corrosion depth of the weld metal was measured. The result is shown in FIG. The thickness of the weld metal tested was 2.9 mm.
【0025】図1に示すように、非金属介在物が面積率
で0.01%を超えると孔あき腐食深さが深くなり、P 、Cu
が溶接金属中に複合含有されていても、P 、Cuの耐孔あ
き腐食性に対する効果がなくなる。したがって、溶接金
属中の硫化物系および酸化物系の非金属介在物は面積率
で0.01%以下とする。As shown in FIG. 1, when the area ratio of non-metallic inclusions exceeds 0.01%, the depth of perforated corrosion becomes deep, and P, Cu
Even if it is contained in the weld metal as a composite, the effect of P and Cu on the pitting corrosion resistance is lost. Therefore, the area ratio of sulfide-based and oxide-based nonmetallic inclusions in the weld metal is 0.01% or less.
【0026】つぎに、オイルパンについて詳細に説明す
る。発明者らは、溶接ビード部の耐食性を向上するため
に、Cu系溶接ワイヤに着目して種々検討を行った。Next, the oil pan will be described in detail. In order to improve the corrosion resistance of the weld bead portion, the inventors have paid attention to a Cu-based welding wire and conducted various studies.
【0027】Fe系溶接ワイヤとCu系溶接ワイヤの溶接ビ
ードについて、耐食性を調査した。溶接ビードは表1に
示す化学組成の溶接ワイヤを用いてビードを置き、この
溶接ビードについて腐食試験を行った。The corrosion resistance of the weld beads of the Fe-based welding wire and the Cu-based welding wire was investigated. The weld bead was placed using a welding wire having the chemical composition shown in Table 1, and a corrosion test was performed on this weld bead.
【0028】Cu系溶接ワイヤのミグブレージング溶接条
件は下記の通りである。 ワイヤ径:0.8mm 、シールドガス:純Arガス 15l/min 溶接電流:110A 、溶接電圧: 16V、溶接速度:60cm/m
in 溶接姿勢:下向きThe MIG brazing welding conditions for the Cu-based welding wire are as follows. Wire diameter: 0.8mm, Shielding gas: Pure Ar gas 15l / min Welding current: 110A, Welding voltage: 16V, Welding speed: 60cm / m
in Welding position: downward
【0029】腐食試験は塩水噴霧(50℃、 5%NaCl、1
h)→乾燥(30℃、6h)→湿潤(50℃、湿度95%、1h)
を1サイクルとして 120サイクル実施し、その後、ビー
ドの最大腐食深さを測定した。その結果を表1に併記し
た。The corrosion test was carried out using a salt spray (50 ° C., 5% NaCl, 1
h) → Dry (30 ℃, 6h) → Wet (50 ℃, 95% humidity, 1h)
Was carried out for 120 cycles, and then the maximum corrosion depth of the bead was measured. The results are also shown in Table 1.
【0030】[0030]
【表1】 [Table 1]
【0031】表1に示すように、Cu系溶接ワイヤを用い
たビードは、最大腐食深さが 0.1mmで、Fe系のそれに比
較して 1/8と浅くなっている。したがって、Cu系溶接ワ
イヤを用いることによって、溶接ビード部の耐食性を著
しく向上させることができる。As shown in Table 1, the bead using the Cu-based welding wire has a maximum corrosion depth of 0.1 mm, which is 1/8 that of the Fe-based bead. Therefore, the use of the Cu-based welding wire can significantly improve the corrosion resistance of the weld bead portion.
【0032】Cu系溶接ワイヤのミグブレージング溶接で
の問題は入熱不足および鋼板溶融過多に起因する継手強
度不足である。前者の問題は一般に入熱の増大によって
対処しうるが、入熱の増大は溶接時のワイヤ狙い位置、
溶接姿勢にもよるが、鋼板の溶融量を高めることにな
る。一般に、Cu中に固溶し得るFeの量はきわめて少量で
あることから、鋼板の溶融は結果的に溶接金属中にFe系
のいわゆる異物を混在することになる。Problems in MIG brazing welding of Cu-based welding wires are insufficient heat input and insufficient joint strength due to excessive melting of steel sheets. The former problem can generally be dealt with by increasing the heat input, but the increase in heat input is the target position of the wire during welding.
Although it depends on the welding position, the melting amount of the steel sheet is increased. In general, the amount of Fe that can be solid-dissolved in Cu is extremely small, so that the melting of the steel sheet results in the inclusion of Fe-based so-called foreign matter in the weld metal.
【0033】溶接金属中の多量の異物(Fe系分散相)は
溶接継手の静的および動的強度を劣化させるほか、異物
がビード表面に現れた場合には、腐食環境下でFe系部分
が優先的に腐食してピット状外観を呈するなどの弊害も
ある。A large amount of foreign matter (Fe-based dispersed phase) in the weld metal deteriorates the static and dynamic strength of the welded joint, and when foreign matter appears on the bead surface, the Fe-based portion is corroded in a corrosive environment. There are also harmful effects such as preferential corrosion and a pit-like appearance.
【0034】溶接金属中のFe系分散相の量と継手疲労強
度との関係を図4に示す。ここでCu系溶接ワイヤを用い
た溶接金属中のFe系分散相の量は、溶接時のワイヤの狙
い位置、角度、溶接電流、溶接電圧および溶接速度を変
化させることによって変えている。FIG. 4 shows the relationship between the amount of Fe-based dispersed phase in the weld metal and the joint fatigue strength. Here, the amount of Fe-based dispersed phase in the weld metal using the Cu-based welding wire is changed by changing the target position, angle, welding current, welding voltage and welding speed of the wire during welding.
【0035】同図において、溶接金属中へのFe系分散相
の混入量が増すと疲労強度が低下することがわかる。と
くにFe系分散相の量が 6%を超える混入領域での強度低
下が大きい。溶融金属中の未固溶Feは溶融プールの表面
近傍に集積する傾向があり、多量のFe系分散相の混入に
よって、溶接金属の強度が低下し、さらに表面の欠陥の
増大によって疲労強度の低下が大きくなると考えられ
る。In the figure, it can be seen that the fatigue strength decreases as the amount of the Fe-based dispersed phase mixed in the weld metal increases. In particular, the strength is greatly reduced in the mixed region where the amount of Fe-based dispersed phase exceeds 6%. The undissolved Fe in the molten metal tends to accumulate near the surface of the molten pool, the strength of the weld metal decreases due to the incorporation of a large amount of Fe-based dispersed phase, and the fatigue strength decreases due to the increase in surface defects. Is expected to grow.
【0036】Fe系分散相の混入は、本実験(図4)では
約20%が最大となったが、突き合わせ継手などのように
溶接時に鋼板部分を多量に溶融させて接合する方式で
は、Cu系溶接ワイヤを用いた溶接金属中へのFe系分散相
の混入はきわめて大きくなり、強度、靱性の低下への影
響が著しくなると考えられる。したがって、本発明では
溶接金属内に混在するFe系の分散相の面積率を 6%以下
に限定した。In the present experiment (Fig. 4), the mixing of the Fe-based dispersed phase was maximum at about 20%. However, in the method of melting a large amount of the steel plate portion at the time of welding, such as a butt joint, Cu is used. It is considered that the mixing of the Fe-based dispersed phase into the weld metal using the system-based welding wire becomes extremely large, and the influence on the reduction of strength and toughness becomes significant. Therefore, in the present invention, the area ratio of the Fe-based dispersed phase mixed in the weld metal is limited to 6% or less.
【0037】つぎに、オイルパンのCu系溶接ワイヤの化
学成分の限定理由について説明する。前述のように、Cu
系溶接ワイヤ中のFe量はできるだけ低く抑えるのが望ま
しい。したがって、実生産でのFe量低減コストを考慮し
て、Cu系溶接ワイヤ中のFe含有量は0.2 %以下に限定し
た。Next, the reasons for limiting the chemical composition of the Cu-based welding wire of the oil pan will be described. As mentioned above, Cu
It is desirable to keep the Fe content in the system welding wire as low as possible. Therefore, the Fe content in the Cu-based welding wire was limited to 0.2% or less in consideration of the cost of reducing the Fe content in actual production.
【0038】Siは溶融金属のぬれ性を高める元素であ
り、 2.0%以上含有されれば、オイルパン溶接でビード
端面をなだらかにして鋼板との接合界面を大きくするほ
か、疲労強度、美観の向上効果も期待できる。しかしな
がら、 6.0%を超えるとκ−CuSiの金属間化合物を形成
し耐孔あき腐食性が劣る等の問題が生じる。したがっ
て、Cu系溶接ワイヤ中のSi含有量は 2.0〜6.0 %に特定
した。Si is an element that enhances the wettability of molten metal. If it is contained in an amount of 2.0% or more, the end face of the bead is smoothed by oil pan welding to increase the joint interface with the steel sheet, and fatigue strength and aesthetics are improved. You can expect an effect. However, if it exceeds 6.0%, intermetallic compounds of κ-CuSi are formed and problems such as poor corrosion resistance against pitting occur. Therefore, the Si content in the Cu-based welding wire was specified to be 2.0 to 6.0%.
【0039】Cu系溶接ワイヤには、これらの元素のほか
にMn、Ni、P などを含有しても本発明の目的を損なうこ
とはないが、通常軟鋼板が使用されるオイルパンではF
e、Si、Cu以外の元素は総和で 3%以下に抑えるべきで
ある。Although the Cu-based welding wire contains Mn, Ni, P and the like in addition to these elements, it does not impair the object of the present invention.
Elements other than e, Si, and Cu should be kept under 3% in total.
【0040】[0040]
【実施例】以下に、アーク溶接構造物の実施例について
説明する。表2に示す耐食性鋼板と溶接ワイヤを種々組
み合わせて、通常のアーク溶接条件で溶接構造物を製作
し、これらの溶接構造物の重ね継手部の溶接金属につい
て腐食試験を行った。腐食試験は(50℃、湿度85%、11
h )→(50℃、湿度30%、3h)→(20℃、湿度60%、5
h)を1サイクルとして 120サイクル実施し、その後、
溶接金属の孔あき腐食深さを測定した。その結果を表3
に示す。EXAMPLES Examples of arc welded structures will be described below. Various combinations of the corrosion resistant steel plates and welding wires shown in Table 2 were used to fabricate welded structures under normal arc welding conditions, and a corrosion test was performed on the weld metal of the lap joint of these welded structures. Corrosion test (50 ℃, 85% humidity, 11
h) → (50 ° C, humidity 30%, 3h) → (20 ° C, humidity 60%, 5
h) as one cycle and 120 cycles, then
The perforated corrosion depth of the weld metal was measured. The results are shown in Table 3.
Shown in.
【0041】実施例の溶接金属の化学成分、非金属介在
物および腐食試験における最大孔あき腐食深さを表3に
示す。表3から明らかなように、本発明のアーク溶接構
造物の溶接金属の最大孔あき腐食深さは0.50mm以下で、
良好な耐孔あき腐食性を有している。Table 3 shows the chemical composition, non-metallic inclusions and maximum perforated corrosion depth of the weld metal of the examples. As is clear from Table 3, the maximum perforated corrosion depth of the weld metal of the arc welded structure of the present invention is 0.50 mm or less,
Has good pitting corrosion resistance.
【0042】一方、比較例であるNo.4〜6 は溶接金属中
の非金属介在物が多く、No.7はC が多く、No.8はP が少
なく、No.9はCuが少ないため、比較例の最大孔あき腐食
深さは0.80mm〜1.20mmで、耐孔あき腐食性が著しく低下
している。On the other hand, Comparative Examples Nos. 4 to 6 have a lot of non-metallic inclusions in the weld metal, No. 7 has a large amount of C, No. 8 has a small amount of P, and No. 9 has a small amount of Cu. The maximum pitting corrosion depth of the comparative example is 0.80 mm to 1.20 mm, and the pitting corrosion resistance is remarkably reduced.
【0043】[0043]
【表2】 [Table 2]
【0044】[0044]
【表3】 [Table 3]
【0045】つぎに、オイルパンの実施例について説明
する。軟鋼板を用いて、上下槽二段からなるオイルパン
をCu系溶接ワイヤを用いて、ミグブレージング溶接で製
造した。上下槽の接合は全周Cu系溶接ワイヤを用いて、
ミグブレージング溶接で行った。溶接部の断面形状を図
2に示す。Next, an example of the oil pan will be described. Using a mild steel plate, an oil pan consisting of two stages of upper and lower tanks was manufactured by Mig brazing welding using a Cu-based welding wire. For the joining of the upper and lower tanks, using the entire circumference Cu-based welding wire,
It was performed by MIG brazing welding. The sectional shape of the welded portion is shown in FIG.
【0046】図2(a) は従来のFe系溶接ワイヤを用いた
ミグ溶接の断面で、ビード形状が凸形であり、強度、美
観の面から好ましい形状とはいえない。一方、(b) はCu
系溶接ワイヤを用いたミグブレージング溶接の断面で、
溶接金属の流れが良好でビード形状がなだらかで、Siが
添加されているため鋼板とのぬれ性がよく、ビード端面
がなだらかになり、接合界面が大きくなっている。した
がって、このビード形状は疲労強度、美観の面から好ま
しい形状となっている。なお、(b) は溶接ビードと鋼板
の境界が接合不十分のように見えるが、これは、ナイタ
ール腐食によって境界が深くエッチングされたためであ
り、両者の接合強度にはなんら問題はない。FIG. 2 (a) is a cross section of MIG welding using a conventional Fe-based welding wire, and the bead shape is convex, which is not a preferable shape in terms of strength and aesthetics. On the other hand, (b) is Cu
In the cross section of MIG brazing welding using the system welding wire,
The flow of the weld metal is good, the bead shape is gentle, and since Si is added, the wettability with the steel sheet is good, the bead end surface is gentle, and the joint interface is large. Therefore, this bead shape is a preferable shape from the viewpoint of fatigue strength and aesthetics. In addition, in (b), the boundary between the weld bead and the steel plate seems to be insufficiently joined, but this is because the boundary was deeply etched due to nital corrosion, and there is no problem in the joint strength between the two.
【0047】図3にCu系溶接ワイヤを用いたミグブレー
ジング溶接部の顕微鏡組織を示す。図3に示すように、
溶接金属中に混在するFe系分散相の面積率は 6%以下
で、溶接ビード部の疲労強度が良好であることがわか
る。FIG. 3 shows a microstructure of a MIG brazing welded portion using a Cu welding wire. As shown in FIG.
The area ratio of the Fe-based dispersed phase mixed in the weld metal is 6% or less, which shows that the fatigue strength of the weld bead is good.
【0048】オイルパンは自動車にとって重要な部品で
あり、走行中の腐食、衝撃などによるき裂の発生は許さ
れない。したがって、上下槽の接合では十分な精度が求
められるが、図2(b) に示したように、Cu系溶接ワイヤ
を用いたミグブレージング溶接ではビード形状が良いた
め、この要求を十分に満足することができる。The oil pan is an important part for automobiles, and cracks due to corrosion and impact during traveling are not allowed. Therefore, sufficient accuracy is required for joining the upper and lower tanks, but as shown in Fig. 2 (b), the bead shape is good in MIG brazing welding using Cu-based welding wire, so this requirement is sufficiently satisfied. be able to.
【0049】以上のように、本発明の鋼板製オイルパン
は耐孔あき腐食性が良好なため、溶接ビード部の疲労強
度も高く、エンジンオイルの漏れもなく、長期間の使用
に耐え得ることができる。As described above, since the steel plate oil pan of the present invention has good perforation corrosion resistance, the weld bead portion has high fatigue strength, engine oil does not leak, and it can withstand long-term use. You can
【0050】[0050]
【発明の効果】本発明のアーク溶接構造物は、溶接金属
の化学成分がC:0.05%以下、P:0.03%超え0.20%以下、
Cu:0.20 %超え1.00%以下を満足し、かつ溶接金属中に
硫化物系および酸化物系の非金属介在物が面積率で0.01
%以下で、さらに溶接構造物の鋼板の化学成分を限定し
た耐孔あき腐食性の優れたアーク溶接構造物である。し
たがって、本発明のアーク溶接構造物は過酷な環境下で
溶接金属の耐食性が良いため、耐孔あき腐食性に優れ長
期間の使用にも十分耐え得ることができる。また、本発
明のオイルパンは、Fe:0.2%以下、Si:2.0〜6.0 %を含
有するCu系溶接ワイヤを用いてミグブレージング溶接さ
れた複数の槽からなる鋼板製のオイルパンであって、溶
接金属内に混在するFe系の分散相の面積率が 6%以下で
ある耐孔あき腐食性の優れた鋼板製オイルパンである。
したがって、本発明のオイルパンは溶接ビード部の耐食
性が良いため耐孔あき腐食性に優れ、かつ継手強度も良
好であるため、長期間の使用にも十分耐え得ることがで
きる。The arc-welded structure of the present invention has a chemical composition of the weld metal of C: 0.05% or less, P: 0.03% or more and 0.20% or less,
Cu: More than 0.20% and 1.00% or less is satisfied, and the area ratio of sulfide-based and oxide-based non-metallic inclusions is 0.01 in the weld metal.
% Or less, the arc-welded structure is excellent in perforation corrosion resistance by limiting the chemical composition of the steel plate of the welded structure. Therefore, since the arc-welded structure of the present invention has good corrosion resistance of the weld metal in a harsh environment, it has excellent resistance to perforation corrosion and can sufficiently withstand long-term use. Further, the oil pan of the present invention is Fe: 0.2% or less, Si: a steel plate-made oil pan consisting of a plurality of tanks Mig brazed by using a Cu-based welding wire containing 2.0 to 6.0%, It is a steel plate oil pan with excellent perforation and corrosion resistance in which the area ratio of the Fe-based dispersed phase mixed in the weld metal is 6% or less.
Therefore, the oil pan of the present invention has good corrosion resistance at the weld bead portion, has excellent perforation corrosion resistance, and has good joint strength, and therefore can sufficiently withstand long-term use.
【図1】非金属介在物の面積率と孔あき腐食深さとの関
係を示す図である。FIG. 1 is a diagram showing the relationship between the area ratio of non-metallic inclusions and the depth of perforated corrosion.
【図2】溶接部の断面形状を示す図で、(a) は従来のFe
系溶接ワイヤを用いたミグ溶接の断面を、(b) はCu系溶
接ワイヤを用いたミグブレージング溶接の断面を示す図
である。FIG. 2 is a view showing a cross-sectional shape of a welded portion, (a) is a conventional Fe
FIG. 3B is a diagram showing a cross section of MIG welding using a system welding wire, and FIG. 9B is a diagram showing a cross section of MIG brazing welding using a Cu welding wire.
【図3】Cu系溶接ワイヤを用いたミグブレージング溶接
部の顕微鏡組織を示す図である。FIG. 3 is a view showing a microstructure of a MIG brazing weld portion using a Cu welding wire.
【図4】溶接金属中のFe系分散相の量と継手疲労強度と
の関係を示す図である。FIG. 4 is a diagram showing the relationship between the amount of Fe-based dispersed phase in the weld metal and the joint fatigue strength.
【図5】重ね継手部の溶接金属の断面形状を示す図であ
る。FIG. 5 is a view showing a cross-sectional shape of the weld metal of the lap joint.
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成6年6月30日[Submission date] June 30, 1994
【手続補正1】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】図3[Name of item to be corrected] Figure 3
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【図3】Cu系溶接ワイヤを用いたミグブレージング溶接
部の顕微鏡組織を示す写真である。FIG. 3 is a photograph showing a microstructure of a MIG brazing weld using a Cu-based welding wire.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 FI 技術表示箇所 F02F 7/00 302 Z (72)発明者 横井 利雄 兵庫県加古川市金沢町1番地 株式会社神 戸製鋼所加古川製鉄所内 (72)発明者 松本 正人 兵庫県加古川市金沢町1番地 株式会社神 戸製鋼所加古川製鉄所内─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification number Reference number within the agency FI Technical indication location F02F 7/00 302 Z (72) Inventor Toshio Yokoi 1 Kanazawa-machi, Kakogawa-shi, Hyogo Kamido Co., Ltd. Steel Works Kakogawa Steel Works (72) Inventor Masato Matsumoto 1 Kanazawa Town, Kakogawa City, Hyogo Prefecture Kadodo Steel Works Kakogawa Steel Works
Claims (5)
であって、溶接金属の化学成分がC:0.05%以下、P:0.03
%超え0.20%以下、Cu:0.20 %超え1.00%以下を満足
し、かつ溶接金属中に硫化物系および酸化物系の非金属
介在物が面積率で0.01%以下であることを特徴とする耐
孔あき腐食性の優れたアーク溶接構造物。1. A welded structure welded by arc welding, wherein the chemical composition of the weld metal is C: 0.05% or less, P: 0.03.
%, 0.20% or less, Cu: 0.20% or more and 1.00% or less, and 0.01% or less in area ratio of sulfide-based and oxide-based nonmetallic inclusions in the weld metal. Arc welded structure with excellent perforation and corrosion.
以下、P:0.03%超え0.20%以下、Cu:0.20 %超え1.00%
以下、Si:1.0%以下、Mn:0.10 %超え1.50%以下、 S:
0.005%以下、Al:0.01 %超え0.06%以下である請求項
1の耐孔あき腐食性の優れたアーク溶接構造物。2. The chemical composition of the steel plate of the welded structure is C: 0.05%
Below, P: 0.03% over 0.20%, Cu: 0.20% over 1.00%
Below, Si: 1.0% or less, Mn: 0.10% to 1.50% or less, S:
The arc-welded structure having excellent corrosion resistance against pitting according to claim 1, wherein 0.005% or less and Al: more than 0.01% and 0.06% or less.
にNi、Nb、Ti、V 、Cr、Mo、Zrの内から選んだ少なくと
も1種以上を0.3 %以下含む請求項2の耐孔あき腐食性
の優れたアーク溶接構造物。3. The perforation-proof perforation according to claim 2, further comprising at least one selected from Ni, Nb, Ti, V, Cr, Mo and Zr as a chemical component of the steel plate of the welded structure in an amount of 0.3% or less. Arc welded structure with excellent corrosiveness.
にCaおよび/またはREMを0.0050%以下含む請求項2
または請求項3の耐孔あき腐食性の優れたアーク溶接構
造物。4. The chemical composition of the steel plate of the welded structure further contains 0.0050% or less of Ca and / or REM.
Alternatively, the arc-welded structure having excellent perforation corrosion resistance according to claim 3.
Cu系溶接ワイヤを用いてミグブレージング溶接された複
数の槽からなる鋼板製のオイルパンであって、溶接金属
内に混在するFe系の分散相の面積率が 6%以下であるこ
とを特徴とする耐孔あき腐食性の優れた鋼板製オイルパ
ン。5. Fe: 0.2% or less and Si: 2.0 to 6.0% are contained.
A steel plate oil pan consisting of multiple tanks that are MIG-Brazed welded using Cu-based welding wire, characterized in that the area ratio of the Fe-based dispersed phase mixed in the weld metal is 6% or less. Steel pan oil pan with excellent perforation and corrosion resistance.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3996194A JPH07252587A (en) | 1994-03-10 | 1994-03-10 | Arc welded structure and oil pan excellent in pitting corrosion resistance |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3996194A JPH07252587A (en) | 1994-03-10 | 1994-03-10 | Arc welded structure and oil pan excellent in pitting corrosion resistance |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH07252587A true JPH07252587A (en) | 1995-10-03 |
Family
ID=12567562
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3996194A Pending JPH07252587A (en) | 1994-03-10 | 1994-03-10 | Arc welded structure and oil pan excellent in pitting corrosion resistance |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH07252587A (en) |
-
1994
- 1994-03-10 JP JP3996194A patent/JPH07252587A/en active Pending
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP2009185382A (en) | Ferritic stainless steel sheet having excellent corrosion resistance in welding gap oxide film | |
JP5137412B2 (en) | Gas shielded arc welding method for galvanized steel bar and stainless steel plate | |
MXPA97007729A (en) | Solded gasket that has excellent resistance to the fat | |
JP4452204B2 (en) | Steel plate for brazing joint with aluminum material, joining method and joint using the steel plate | |
JPH0825041B2 (en) | Clad steel pipe manufacturing method | |
JP5059455B2 (en) | Steel plate for brazing joint with aluminum material, joining method and joint using the steel plate | |
JP4640995B2 (en) | Steel plate for brazing joint with aluminum material, joining method and joint using the steel plate | |
JP3819755B2 (en) | Welding method of high corrosion resistance high Mo austenitic stainless steel | |
JP2000015447A (en) | Welding method of martensitic stainless steel | |
JPH08132238A (en) | Welding method of high cr steel | |
JP4736193B2 (en) | Fillet welded joint with excellent fatigue characteristics and gas shielded arc fillet welding method | |
JPH07252587A (en) | Arc welded structure and oil pan excellent in pitting corrosion resistance | |
JP2711071B2 (en) | Bond flux for submerged arc welding | |
JPS60121099A (en) | Compound wire for welding | |
JPH06340947A (en) | Lap arc-welded joint structure excellent in fatigue strength | |
JP3165902B2 (en) | High Cr steel welding method | |
JP3184657B2 (en) | Covered arc welding rod for high Cr ferritic heat resistant steel | |
JP4452205B2 (en) | Steel plate for brazing joint with aluminum material, joining method and joint using the steel plate | |
JP2575250B2 (en) | Line pipe with excellent corrosion resistance and weldability | |
JP7508013B1 (en) | Welded joint and manufacturing method thereof | |
JP2711554B2 (en) | Hot dip galvanizing prevention method | |
JPH05331596A (en) | Galvannealed steel plate, using high strength hot rolled starting plate, excellent in fatigue characteristic in weld zone and its production | |
JP2642835B2 (en) | Corrosion protection method for seawater-resistant steel welds | |
JP2558403B2 (en) | Line pipe with excellent corrosion resistance and weldability | |
JP2000001752A (en) | Welded joint excellent in corrosion resistance and fatigue strength |