JP4400058B2 - Ferritic stainless steel welded pipe with excellent spinning processability - Google Patents

Description

【００４２】
【表２】

【００４３】
【表３】

【００４４】
【表４】

【００４５】
【表５】

【００４６】
本発明例はいずれも、極めて優れたスピニング加工性を有する溶接管となっている。一方、本発明の範囲を外れる比較例はスピニング加工性が劣化している。
【００４７】
【発明の効果】
以上のように、本発明のフェライト系ステンレス鋼溶接管は、とくにスピニング加工時の加工速度を高速化した場合であっても良好なスピニング加工性を有し、スピニング加工時の溶接部の破断や欠け落ちを格段に低減することができ、生産能率を格段に向上でき、産業上格段の効果を奏する。また、本発明のフェライト系ステンレス鋼溶接管は、排気系膨径部材用鋼管としても適用できるという効果もある。
【図面の簡単な説明】
【図１】 溶接管の溶接金属部の溶込み深さ、溶接金属部の管内面側幅の定義を示す説明図である。
【図２】触媒コンバーターのハウジングの形状の一例を模式的に示す説明図である。
【図３】スピニング加工時に発生する管端の溶接部の破断や、溶接部の欠け落ちの一例を模式的に示す説明図である。
【図４】実施例に使用したスピニング加工装置の構成を模式的に示す説明図である。
【図５】 実施例に使用したスピニング加工装置の構成を模式的に示す説明図である。
【符号の説明】
１ 素管
２ スピンドル
３ 把持機構
４ 成形ローラ群
４ａ、４ｂ、４ｃ 成形ローラ
５ 回転台
６ 基台
７ 把持機構
８ 移動テーブル
９ モータケース
11a ハウジングの本体部
11b ハウジングのコーン部
11c ハウジングの接続部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ferritic stainless steel welded pipe suitable for use in automobile exhaust system members, and particularly for exhaust system expanded diameter members and reduced diameter members such as mufflers and catalytic converter housings manufactured by spinning a steel pipe. It is related with a ferritic stainless steel welded tube suitable as the above.
[0002]
[Prior art]
Conventionally, ferritic stainless steels such as SUH 409L, SUS 429, and SUS 436L, which are excellent in workability and corrosion resistance, are frequently used for automobile exhaust system members. An example is a housing or a muffler of a catalytic converter that processes exhaust gas discharged from an automobile engine.
[0003]
A typical container shape of the catalytic converter housing is shown in FIG.
The catalytic converter housing 11 includes a relatively large-diameter main body 11a that houses the catalyst carrier, a relatively small-diameter connection portion 11c that is connected to the exhaust pipe, and a taper that gradually decreases in diameter from the main body 11a toward the connection portion 11c. And a cone-shaped cone portion 11b.
[0004]
In recent years, the housing 11 of such a catalytic converter is often formed by subjecting an element pipe (welded pipe) having the same diameter as that of the main body 11a to a spinning process. For example, in Patent Document 1, a processing roll including a drawing roll and a guide roll along a processing axial direction with one end of a base tube fitted on a rotating metal core and the other end as a free end, Plurally symmetrically arranged around the processing axis center on the outer periphery, the raw tube is gripped by the guide roll by multi-cycle idle drawing, and drawn into a rough shape by the drawing roll, and then along the core metal by the drawing roll Pipe shrinkage processing methods that perform ironing have been proposed.
[0005]
Further, in Patent Document 2, the raw tube is gripped by three rollers, and the rollers are arranged so that the difference with respect to the geometric spiral angle determined by the relative movement speed in the longitudinal direction of the roller and the number of rotations of the tube is within 1 degree. A method of manufacturing a tapered steel pipe is proposed in which the three pipes and the pipe are moved relative to each other in the longitudinal direction while the rollers are moved in the pipe radial direction to taper the pipe. ing.
[0006]
As described in Patent Document 1 and Patent Document 2, a method of forming a tubular material having a taper by spinning is performed by forming a plate material into a member having a predetermined shape by press working, and then joining the members by welding to form a tubular material having a taper. Compared with the manufacturing method, (1) material yield is good, (2) integral molding is possible and reliability of welded parts is not lowered, (3) no mold is required, and (4) man-hours are reduced. There are advantages such as less. However, compared with the method using press working, the method using spinning processing has a problem that the production efficiency is low because the spinning processing requires a relatively long time.
[0007]
For such a problem, for example, in Patent Document 3, the raw pipe is rotated around the pipe axis, and a plurality of forming rollers arranged on the outer periphery of the raw pipe are revolved in the direction opposite to the rotation direction of the raw pipe, There has been proposed a spinning method in which a raw pipe is moved in the pipe axial direction and a forming roll is moved in the radial direction of the raw pipe to form a reduced diameter portion in the raw pipe. In the technique described in Patent Document 3, the relative rotational speed is increased, high-speed machining can be performed, and the machining time can be shortened.
[0008]
[Patent Document 1]
Japanese Patent Publication No. 4-46647 [Patent Document 2]
Japanese Patent Laid-Open No. 10-24323 [Patent Document 3]
Japanese Patent Laid-Open No. 2000-33443
[Problems to be solved by the invention]
However, if the technique described in Patent Document 3 is applied to spin the steel pipe to form a reduced diameter portion, the weld W may be broken at the end of the pipe (FIG. 3 (a)) or FIG. There has been a problem that the probability of chipping X of the welded portion W as shown in b) becomes high.
[0010]
The present invention advantageously solves the above-described problems of the prior art, and even if spinning processing is performed at a higher processing speed, the probability of fracture of the welded portion at the pipe end and chipping of the welded portion is extremely low. The object is to propose a ferritic stainless steel welded pipe with excellent spinning workability.
[0011]
[Means for Solving the Problems]
In order to achieve the above-mentioned problems, the present inventors have conducted a thorough investigation and examination on the influence of the microstructure of the weld metal part and the steel plate component on the spinning workability of the welded pipe. As a result, the probability of breakage of the welded part at the pipe end during spinning processing and chipping of the welded part varies depending on the welding conditions of the welded pipe, so by controlling the cross-sectional shape of the welded metal part, It has been found that the probability of fracture of the welded portion and chipping of the welded portion is drastically reduced, and the spinning workability of the welded pipe is remarkably improved.
[0012]
Moreover, even if the cross-sectional shape of the weld metal part is the same, the probability of chipping of the weld part differs depending on the steel plate composition, so the contents of C, Si, Mn, P, S, Ni and Al are regulated, and Ti and / or Or the knowledge that the probability of the fracture of the welded part or the chipped part of the welded part during spinning is drastically reduced by using a steel plate composition containing a certain amount of Nb was obtained.
[0013]
The present invention has been completed based on the above findings and further studies. That is, the gist of the present invention is as follows.
(1) A ferritic stainless steel welded tube obtained by butt welding the ends of a ferritic stainless steel plate processed into a tubular shape by arc welding , wherein the ferritic stainless steel plate is in mass% and C: 0.020% Si: 0.08% to 1.0%, Mn: 0.12% to 1.0%, P: 0.012% to 0.040%, S: 0.010% or less, Cr: 10.0 to 20.0%, Ni: 0.1% to 0.6% , Al: 0.01% or more and 0.10% or less, N: 0.020% or less, Nb: 0.10 to 1.00% and Ti: 0.10 to 1.00% The weld metal part formed by welding has a composition comprising Fe and inevitable impurities, and the weld metal part has a penetration depth of 0.9 times or more of the ferritic stainless steel sheet thickness and the ferritic stainless steel sheet thickness. Have the following tube inner side width A ferritic stainless steel welded pipe with excellent spinning workability.
(2) In (1), in addition to the above composition, in addition to mass, one or two selected from V: 0.01 to 0.5%, W: 0.001 to 0.05%, Co: 0.01 to 0.25% A ferritic stainless steel welded pipe characterized by containing the above.
(3) In (1) or (2), in addition to the above-mentioned composition, in addition to mass, Cu: 0.1% or more and 3.0% or less, Mo: 0.4% or more and 3.0% or less, selected from 1 type or 2 A ferritic stainless steel welded pipe characterized by containing a seed.
(4) The ferritic stainless steel welded pipe according to any one of (1) to (3), further containing B: 0.0002 to 0.0030% by mass% in addition to the above composition.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be specifically described below.
The welded pipe of the present invention is a ferritic stainless steel welded pipe formed by butt welding the ends of ferritic stainless steel sheets processed into a tubular shape. The ferritic stainless steel plate is preferably a cold rolled steel plate. In the welded pipe of the present invention, the weld metal portion formed by welding has a penetration depth of 0.9 times the steel plate thickness as shown in FIG. 1 (a), and as shown in FIG. It has a cross-sectional shape having a tube inner surface side width equal to or less than the steel plate thickness. It should be noted that “below the steel plate thickness” in the tube inner surface width of the weld metal portion includes zero when the weld metal is not formed on the tube inner surface side, that is, zero.
[0015]
Penetration depth of weld metal part: 0.9 times or more of steel plate thickness If the penetration depth of weld metal part is as small as less than 0.9 times the steel plate thickness, the strength of the weld zone will be insufficient and the inner surface of the pipe will be welded. The butted portion becomes a non-penetrating portion, acts as a notch, concentrates the circumferential tensile stress acting on the welded pipe during the spinning process, and breaks the weld at the pipe end. For this reason, the penetration depth of the weld metal part was limited to 0.9 times or more of the steel plate thickness.
[0016]
Pipe inner side width of weld metal part: steel sheet thickness or less If the inner pipe side width of weld metal part exceeds the steel sheet thickness, the weld metal is formed in a convex shape on the pipe inner side, and welded to the steel sheet base metal Since the vicinity of the boundary with the metal part (bond part) is concave, the tensile stress in the circumferential direction is concentrated on the bond part, cracks are likely to occur, and chipping of the weld part is likely to occur. In order to prevent the vicinity of the boundary between the steel plate base metal and the weld metal part from becoming concave, the pipe inner surface side width of the weld metal part should be zero so as not to form the weld metal part on the pipe inner surface side. preferable. For this reason, the inner surface side width of the weld metal part is limited to a steel sheet thickness including zero or less.
[0017]
Next, the reason for limiting the composition of the ferritic stainless steel sheet constituting the welded pipe of the present invention will be described. Hereinafter, “%” in relation to the composition means mass% unless otherwise specified.
C: 0.020% or less C is an element that increases the hardness of the welded portion and decreases the toughness, and further decreases the oxidation resistance, which is one of the important characteristics of an automobile exhaust system member. Therefore, in the present invention, it is desirable to reduce it as much as possible, but it is acceptable up to 0.020%. Therefore, in the present invention, C is you limited to 0.020% or less.
[0018]
Si: 0.08% to 1.0%
Si is an element that increases strength and decreases spinning workability and toughness, and it is desirable to reduce it as much as possible, but it is an effective element that improves oxidation resistance. In the present invention, Si is 0.08% or more and 1.0% or less. I decided to limit it to. More preferably, it is 0.12% or more and 0.40% or less.
[0019]
Mn: 0.12% to 1.0%
Mn is an element effective for improving the strength and is preferably contained in an amount of 0.1 2 % or more, but if contained in a large amount of 1.0% or more, the toughness is lowered. Therefore, Mn is you limited to 1.0% or less 0.12% or more.
P: 0.012% or more 0.040% or less P is take effect elemental der to increase the strength, but is contained to 0.012% and containing a large amount exceeding 0.040% the toughness is reduced. Therefore, P is you limited to 0.040% or less to 0.012%.
[0020]
S: 0.010% or less S is combined with Ti to form a sulfide and serves as a starting point for fracture during spinning. Therefore, it is preferably reduced as much as possible in the present invention, but 0.010% is acceptable. Therefore, S is that be limited to 0.010% or less. More preferably, it is 0.005% or less.
[0021]
Cr: 10.0-20.0%
Cr is an element that improves heat resistance and oxidation resistance, and is an indispensable element in ferritic stainless steel sheets. Such an effect becomes remarkable when the content is 10.0% or more. On the other hand, if the content exceeds 20.0%, the toughness decreases. For this reason, Cr are you limited to the range of 10.0 to 20.0 percent.
[0022]
Ni: 0.1% to 0.6%
Ni is Ri advantageously element contributing der to improve toughness, but is 0.1% or more, when the content exceeds 0.6%, leading to oxidation deterioration. Therefore, Ni is you limited to 0.6% or less than 0.1%.
Al: 0.01% or more and 0.10% or less
Al acts as a deoxidizer and combines with N to contribute to the reduction of solid solution N. For this purpose, Al is fully below 0.10% 0.01% or more, Al in the present invention is that be limited to 0.10% or less than 0.01%. The content is more preferably 0.03% or less.
[0023]
N: 0.020% or less N, like C, lowers the toughness of the welded portion, so it is desirable to reduce it as much as possible, but up to 0.020% is acceptable. Therefore, N is the you limited to 0.020% or less. More preferably, it is 0.010% or less.
One or two selected from Nb: 0.10 to 1.00% and Ti: 0.10 to 1.00%
Nb and Ti all have the effect of increasing ductility, toughness, and corrosion resistance, and are contained alone or in combination.
[0024]
Nb and Ti are useful elements that form carbonitrides to reduce solid solution C and N, suppress formation of Cr carbonitrides, and improve ductility, toughness, and corrosion resistance. Nb also has the effect of improving the high temperature strength. Such an effect becomes remarkable when the content of Nb and Ti is 0.10% or more. However, when the content of Nb and Ti exceeds 1.00%, the toughness is reduced. Therefore, Nb is 0.10 to 1.00%, Ti is you limit each scope of 0.10 to 1.00%. More preferably, Nb is 0.30 to 0.50% and Ti is 0.15 to 0.30%.
[0025]
In the present invention, in addition to the basic composition described above, the following components can be appropriately contained as required.
One or more selected from V: 0.01 to 0.5%, W: 0.001 to 0.05%, Co: 0.01 to 0.25%, V, W, and Co are all resistant to weld cracking at the heat affected zone. It is a useful element that improves the above, and one or more elements can be selected and contained as necessary. Such effects are recognized by the contents of V: 0.01% or more, W: 0.001% or more, Co: 0.01% or more, respectively, but when V: 0.5%, W: 0.05%, Co: 0.25% are exceeded, This causes a decrease in the toughness of the base metal and the weld heat affected zone. For this reason, it is preferable to limit to V: 0.01-0.5%, W: 0.001-0.05%, and Co: 0.01-0.25%, respectively.
[0026]
Cu: 0.1% or more and 3.0% or less, Mo: 0.4% or more and 3.0% or less
Both Cu and Mo are elements that improve corrosion resistance, and are preferably selected and contained when high corrosion resistance is required.
Cu is an element that improves corrosion resistance and is preferably contained in an amount of 0.1% or more. However, if it exceeds 3.0%, there is a risk of hot cracking in hot rolling or the like. For this reason, it is preferable to limit Cu to 0.1% or more and 3.0% or less. More preferably , it is 1.0% or less .
[0027]
Mo, similarly Cu, take effect an element der to improve the corrosion resistance, it is preferable to contain 0.4% or more, when the content exceeds 3.0%, not only the spinning workability is deteriorated, the weld heat affected zone Toughness decreases. For this reason, it is preferable to limit Mo to 0.4% or more and 3.0% or less. More preferably , it is 1.3% or less .
B: 0.0002 to 0.0030%
B is an element that particularly improves the toughness of the weld heat-affected zone through the improvement of hardenability, and can be contained if necessary. Such an effect becomes remarkable when the content is 0.0002% or more. However, when the content exceeds 0.0030%, the hardening becomes large, and the toughness and workability deteriorate in both the base material and the weld heat affected zone. For this reason, when B contains, it is preferable to limit to 0.0002 to 0.0030% of range. In addition, More preferably, it is 0.0005 to 0.0010%.
[0028]
The balance other than the above components is Fe and inevitable impurities. As unavoidable impurities, O: 0.015% or less, Mg: 0.0020% or less, Ca: 0.0020% or less are acceptable.
Next, the preferable manufacturing method of the ferritic stainless steel welded pipe of the present invention will be described.
[0029]
Preferably, the molten steel having the ferritic stainless steel composition described above is melted by a known method such as a converter, an electric furnace, a vacuum melting furnace, etc., and then the molten steel is obtained by a continuous casting method or an ingot-bundling method. (Slab).
This steel material is then heated to a predetermined temperature, or directly hot-rolled without heating to obtain a hot-rolled sheet having a predetermined shape. The hot-rolled sheet is usually subjected to hot-rolled sheet annealing, but depending on the application, the hot-rolled sheet annealing may be omitted. Next, the hot-rolled sheet is subjected to pickling treatment and then becomes a cold-rolled sheet by cold rolling. The cold-rolled sheet is then subjected to recrystallization annealing to obtain a ferritic stainless steel sheet (cold-rolled steel sheet) for welded pipes.
[0030]
After processing this cold-rolled steel sheet into a circular tube (pipe shape) by a die process by a known method, the ends of the steel sheet are butt-welded to form a welded tube. Welding method of butt portion between the steel edge in the present invention, the weld metal of a predetermined cross-sectional shape as described above can Ru can be formed, TIG welding, and arc welding method such as a plasma arc welding. Note that a welding material is not necessarily required.
[0031]
Moreover, in order to make a weld metal part into the above-mentioned predetermined cross-sectional shape, adjustment of welding heat input is performed. In the case of arc welding, the welding heat input Q is given by the following equation.
Q = VI / v
Here, Q: welding heat input (J / mm), V: arc voltage (V), I: welding current (A), v: welding speed (mm / s)
By increasing the welding heat input, the penetration depth increases and the inner surface width of the pipe also increases. When the arc voltage V is increased, the welding current I is increased, or the welding speed v is decreased, the welding heat input increases.
[0032]
Hereinafter, the present invention will be described in more detail based on examples.
[0033]
【Example】
Steel having the composition shown in Table 1 was melted in a small vacuum melting furnace to obtain a 100 kg steel ingot. These steel ingots were heated to 1050 to 1250 ° C. and then hot rolled to a finishing temperature of 750 to 950 ° C. and a winding temperature of 650 to 850 ° C. to obtain 4.0 mm hot rolled sheets. In addition, 800-1000 degreeC hot-rolled sheet annealing was performed to some of these hot-rolled sheets. Next, pickling treatment and cold rolling are sequentially performed on these hot-rolled sheets to form cold-rolled sheets having a thickness of 1.2 to 2.0 mm, and then subjected to recrystallization annealing at 850 to 1050 ° C. to obtain cold-rolled steel sheets for welded tubes. .
[0034]
Each obtained cold-rolled steel sheet was cut and then bent with a die to form a substantially circular tube, and the ends of the steel sheets were butted together. Subsequently, the butted portion was welded by a TIG welding method to obtain a welded pipe having a diameter of 1.2 to 2.0 mmt × 120 mmφ × 500 mmL. TIG welding is performed in a shielding gas (argon) atmosphere, with a shielding gas of 20 liters / min on the outer peripheral surface side and 10 liters / min on the inner peripheral surface side. The test was performed under the conditions of 400 mm / min, arc voltage 11 V, and welding current 50 to 105 A. In addition, by adjusting the welding current, the penetration depth of the weld metal portion and the inner surface side width of the weld metal portion were changed.
[0035]
Specimens are taken from the obtained welded pipe, the cross-sectional shape of the weld metal part is observed in the cross section perpendicular to the longitudinal direction of the weld pipe, and the penetration depth of the weld metal part and the inner surface side width of each weld pipe are measured. did.
In addition, the obtained welded pipe was subjected to the spinning processing apparatus shown in FIGS. 4 and 5 with a rotation speed of 500 rpm or 1000 rpm, a tightening amount of 2 mm / time, and a relative parallel movement speed of the forming roll of 8000 mm / min. Spinning was performed to form a product having a shape as shown in FIG.
[0036]
Note that the spinning processing apparatus shown in FIG. 4 includes a rotation driving means, a forming roller 4, and a forming roller moving means (not shown) for moving the forming roller 4. The rotation driving means includes a spindle 2, a gripping mechanism 3 provided on the spindle 2 for gripping the raw tube 1, and a motor (not shown) for rotationally driving the spindle 2, and grips the raw tube 1. And rotate around its axis CC. The forming roller moving means is provided with a numerically controllable servo mechanism (not shown), and in order to form the raw tube 1 into a desired shape, the forming roller 4 and the raw tube 1 are relative to each other based on the set and inputted data. In particular, it is configured to move in the direction of the axis CC and the direction of the diameter D. The forming roller 4 is pressed against the element tube 1 while being moved as indicated by an arrow A in the figure, and the element tube 1 is subjected to spinning drawing into a shape having a conical portion.
[0037]
The spinning processing apparatus shown in FIG. 5 includes a parallel moving means for fixing and holding the raw tube 1 and moving it in the direction of the axis CC, a turntable 5 provided with a forming roller group 4, and a forming roller rotating and moving means. ing.
The parallel moving means has a base 6 for supporting the raw tube 1 and a holding mechanism 7 for holding the raw tube 1 on the moving table 8, and the element is driven by a driving means of the moving table 8 (not shown). The tube 1 can be translated in the direction of the axis CC.
[0038]
The forming roller group 4 includes a plurality of forming rollers 4 a, 4 b, 4 c that impart a predetermined shape to the raw tube 1, and is provided on the turntable 5.
The forming roller rotation moving means includes a turntable 5 having three forming rollers 4a, 4b, and 4c attached thereto, a motor housed in a motor case 9 that rotates the turntable 5 about the axis CC, and further rotation. And a mechanism that is embedded in the table 5 and moves the forming rollers 4a, 4b, and 4c by numerical control in the D direction orthogonal to the axis CC.
[0039]
The forming roller group 4 revolves by rotating the turntable 5 about its axis CC by the forming roller rotation moving means, and the forming rollers 4a, 4b, 4c move in the direction D perpendicular to the axis CC. Can be made.
Spinning was performed on 100 welded pipes under each condition, and the number of occurrences of fracture and chipping in the weld was investigated to evaluate spinning workability. The tightening amount represents an increase in the pressing amount of the forming roll per reciprocation when the forming roll reciprocates relative to the raw tube. In addition, the dimensions of the product are 11c part diameter: 60mmφ, length: 50mm, 11b part (taper part) length: 60mm. The 11a portion has a diameter of 120 mm (original size).
[0040]
Spinning workability is as follows. For each of the 100 welded pipes, the number of fractures or chippings in the welded portion is 0 for ◎, 1-2 for ◯, 3-9 for △, 10 or more. It evaluated as x.
The obtained spinning processability test results are shown in Table 2.
[0041]
[Table 1]

[0042]
[Table 2]

[0043]
[Table 3]

[0044]
[Table 4]

[0045]
[Table 5]

[0046]
Each of the examples of the present invention is a welded pipe having extremely excellent spinning workability. On the other hand, in the comparative example that is out of the scope of the present invention, the spinning processability is deteriorated.
[0047]
【The invention's effect】
As described above, the ferritic stainless steel welded pipe of the present invention has good spinning workability even when the processing speed during spinning is increased, and the welded portion breaks during spinning. Omissions can be significantly reduced, production efficiency can be greatly improved, and there are significant industrial effects. Moreover, the ferritic stainless steel welded pipe of the present invention has an effect that it can also be applied as a steel pipe for exhaust system expanded diameter members.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing definitions of a penetration depth of a weld metal part of a welded pipe and a pipe inner surface side width of the weld metal part.
FIG. 2 is an explanatory view schematically showing an example of the shape of a housing of a catalytic converter.
FIG. 3 is an explanatory diagram schematically showing an example of breakage of a welded portion of a pipe end that occurs during spinning processing and chipping of a welded portion.
FIG. 4 is an explanatory view schematically showing a configuration of a spinning processing apparatus used in Examples.
FIG. 5 is an explanatory view schematically showing a configuration of a spinning processing apparatus used in Examples.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Elementary tube 2 Spindle 3 Grasp mechanism 4 Forming roller group 4a, 4b, 4c Forming roller 5 Rotating stand 6 Base 7 Grasp mechanism 8 Moving table 9 Motor case
11a Housing body
11b Cone part of housing
11c Housing connection

Claims (4)

A ferritic stainless steel welded pipe formed by butt welding the ends of ferritic stainless steel sheets processed into a tubular shape by arc welding ,
The ferritic stainless steel sheet is in mass%,
C: 0.020% or less, Si: 0.08% or more and 1.0% or less,
Mn: 0.12% to 1.0%, P: 0.012% to 0.040%,
S: 0.010% or less, Cr: 10.0-20.0%,
Ni: 0.1% to 0.6%, Al: 0.01% to 0.10%,
N: 0.020% or less, and Nb: 0.10 to 1.00% and Ti: One or two selected from 0.10 to 1.00%, and the balance Fe and inevitable impurities. And
The cross-sectional shape of the weld metal portion formed by the welding has a penetration depth of 0.9 times or more of the thickness of the ferritic stainless steel plate and a pipe inner surface side width of the ferritic stainless steel plate thickness or less. Ferritic stainless steel welded pipe with excellent spinning processability.   In addition to the above composition, the composition further comprises one or more selected from V: 0.01 to 0.5%, W: 0.001 to 0.05%, and Co: 0.01 to 0.25% by mass%. The ferritic stainless steel welded pipe according to claim 1.   2. In addition to the composition, the composition further comprises one or two selected from Cu: 0.1% to 3.0% and Mo: 0.4% to 3.0% in terms of mass%. Or the ferritic stainless steel welded pipe of 2.   The ferritic stainless steel welded pipe according to any one of claims 1 to 3, further comprising B: 0.0002 to 0.0030% by mass% in addition to the composition.

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