JPS5947637B2 - Manufacturing method of pipe clad steel - Google Patents

Description

【発明の詳細な説明】 本発明は、圧延圧着法による、接着強度が高く製 □品
歩留の良い長尺のパイプクラッド鋼の製造方法に関する
。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing long pipe clad steel with high adhesive strength and good product yield using a rolling compression method.

炭素鋼または低合金鋼を母材管とし、ステンレス鋼、ニ
ッケルまたはニッケル合金を合材管とするパイプクラッ
ド鋼は、その優れた耐食性及び機３械的性質を有するこ
とから工業的に有用な製品である。Pipe clad steel, which has carbon steel or low alloy steel as the base material pipe and stainless steel, nickel or nickel alloy as the composite material pipe, is an industrially useful product due to its excellent corrosion resistance and mechanical properties. It is.

従つて従来よりこの優れた特徴を生かすため、高品質で
しかも長尺のパイプクラッド鋼の製造が要望されてきた
。従来よりパイプクラッド鋼の製造法としては、押出し
法がよく知られておレ製造も実施されているが、この方
法は、使用するビレツトを特殊な形状に機械加工する必
要があるうえに、ビレツトの押残り量が多いために歩留
Ｄが悪い等の欠点を有する。Therefore, in order to take advantage of these excellent characteristics, there has been a demand for the production of high quality and long pipe clad steel. The extrusion method is well known as a conventional method for manufacturing pipe clad steel, and it has also been used for manufacturing pipe clad steel, but this method requires machining the billet used into a special shape, and also It has drawbacks such as poor yield D due to a large amount of unpressed material.

その他パイプクラッド鋼の製造方法としては、鋳込み法
、遠心鋳造法、爆発圧着法等が知られているがいずれも
一長一短があり問題が多い。Other known methods for manufacturing pipe clad steel include the casting method, centrifugal casting method, and explosive crimping method, but each method has advantages and disadvantages and many problems.

圧延圧着法によるパイプクラッド鋼の製造方法は上記の
各種製造法に比較し、量産性、品質、歩留レ、製造可能
寸法の点で優れた方法として考案されたものであり、従
来より実施されている。圧延圧着法によるパイプクラッ
ド鋼の製造方法には、大別してつぎの２つの方法がある
。その第１の方法は、例えば特開昭５３−７８９６６号
に示される如く、炭素鋼又は低合金鋼を母材管としてス
テンレス鋼、ニッケル又はニッケル合金を合材管として
嵌合した二重素管を作ク、二重素管の端部を強固に肉盛
溶接した後、これを熱間圧延することによつてパイプク
ラッド鋼を製造する方法である。The method for manufacturing pipe clad steel using the rolling crimping method was devised as a method that is superior to the various manufacturing methods mentioned above in terms of mass productivity, quality, yield ratio, and manufacturable dimensions, and has not been implemented in the past. ing. There are two main methods for producing pipe clad steel using the rolling crimping method: The first method is, for example, as shown in JP-A No. 53-78966, which is a double base pipe in which carbon steel or low alloy steel is used as a base material pipe and stainless steel, nickel or nickel alloy is fitted as a composite material pipe. This is a method of producing pipe clad steel by strongly overlaying the ends of a double pipe and then hot rolling it.

また第２の方法は、例えば特開昭５３−１４１５５号に
示される如く、炭素鋼又は低合金鋼を母材管とし、ステ
ンレス、ニッケルまたはニッケル合金を合材管として嵌
合した二重素管を作つた後、爆発圧着させるか、爆発拡
管又はガス爆発拡管して密接させ、しかる後両端部を強
固に肉盛溶接した二重素管を熱間圧延することによつて
パイプクラッド鋼を製造する方法である。The second method is, for example, as shown in JP-A No. 53-14155, which uses a double base tube in which carbon steel or low alloy steel is used as a base material tube and stainless steel, nickel or nickel alloy is fitted as a composite material tube. After that, pipe clad steel is produced by explosive crimping, explosion tube expansion, or gas explosion tube expansion to bring them into close contact, and then hot rolling a double base tube with both ends firmly overlaid welded. This is the way to do it.

しかし、これらの方法はいずれも下記に示す如き欠点を
有する。However, all of these methods have drawbacks as shown below.

第１の方法では、嵌合後の合材管と母材管との間隙が特
に重要であシ、この間隙が大きい場合には、加熱中およ
び圧延中に肉盛溶接部の全周破断が生じやすく、その結
果被圧着部が酸化され不着部発生の原因となる。In the first method, the gap between the composite pipe and the base metal pipe after fitting is particularly important, and if this gap is large, the overlay weld may break around the entire circumference during heating and rolling. This easily occurs, and as a result, the bonded area is oxidized, causing non-bonding.

この溶接部の破断は、肉盛溶接量および圧延条件の改善
である程度軽減は可能であるが、完全に防止することは
困難である。一方第２の方法では、二重素管の大部分が
密接又は密着状態にあるため、第１の方法で発生する肉
盛溶接部の全周破断の危険性は少ない。しかしこの方法
で用いられる爆発又はガス爆発拡管法は、両端口元部で
の密接度が悪いという欠点を持つため、部分的な溶接部
破断は完全には防止できず、やはク不着部発生の原因と
なつている。部分的に爆発圧着した二重素管を用いる方
法は、両端部の密接度は若干良くなるが、必ずしも良い
結果は期待できない。Although this weld fracture can be reduced to some extent by improving the amount of overlay welding and rolling conditions, it is difficult to completely prevent it. On the other hand, in the second method, since most of the double pipe is in close contact or in close contact, there is less risk of the full circumference rupture of the overlay weld that occurs in the first method. However, the explosion or gas explosion pipe expansion method used in this method has the disadvantage of poor tightness at both ends and openings, so partial weld breakage cannot be completely prevented, and there is a risk of non-bonding. It is the cause. Although the method of using double tubes that are partially explosively crimped improves the closeness of both ends slightly, good results cannot necessarily be expected.

その理由は、部分的な圧着部を有する二重素管を熱間圧
延する場合、圧着部と不圧着部とで圧延時の変形抵抗が
異なク、この部分が圧延圧着されずに合材にしわが発生
したわして歩留低下の原因になるからである。本発明の
目的は、従来の圧延圧着法によるパイプクラツド鋼の製
造方法の欠点を克服し、母材管の内部に合材管を嵌入し
両端を溶接した二重素管の熱間圧延するパイプクラツド
鋼の製造において、この二重素管の両端部で母材管内面
と合材管外面とを密着させ、その密着部の長さｓを合材
管外径の１／２以上とし、前記密着部以外の二重素管の
中間部における母材管内面と合材管外面との間隙を直径
差で合材管外径の１．４チ以下にした二重素管を用いる
ことを特徴とするパイプクラツド鋼の製造方法を提供す
るにある。The reason for this is that when hot-rolling a double blank pipe that has a partially crimped part, the deformation resistance during rolling is different between the crimped part and the non-crimped part. This is because the generation of slag causes a decrease in yield. The purpose of the present invention is to overcome the drawbacks of the conventional manufacturing method of pipe clad steel using the rolling crimping method, and to provide a pipe clad steel that is manufactured by hot rolling a double base pipe in which a composite pipe is inserted into a base pipe and both ends are welded. In manufacturing, the inner surface of the base material tube and the outer surface of the composite material tube are brought into close contact with each other at both ends of the double material tube, and the length s of the adhesive portion is set to be 1/2 or more of the outer diameter of the composite material tube, and the adhesive portion is It is characterized by using a double blank pipe in which the gap between the inner surface of the base material pipe and the outer surface of the composite pipe in the middle part of the double blank pipe is 1.4 inches or less of the outside diameter of the composite pipe in terms of diameter difference. The present invention provides a method for manufacturing pipe clad steel.

本発明は、圧延圧着法によるパイプクラツド鋼の製造に
おける、母材管と合材管との間隙の影響について従来技
術の調査検討、および独自の基礎的実験研究の成果を基
に生まれたものである。The present invention was created based on the results of research and study of conventional technology and original basic experimental research regarding the influence of the gap between the base material pipe and composite material pipe in the production of pipe clad steel by the rolling crimping method. .

すなわち圧延圧着法によるパイプクラツド鋼の製造にお
いて、真に重要なのは、両端口元部の密着性であること
をつきとめた。以下本発明を実施例により図面を参照し
つつ説明する。In other words, we have found that what is truly important in manufacturing pipe clad steel by the rolling crimping method is the adhesion between the openings at both ends. The present invention will be explained below by way of examples with reference to the drawings.

すなわち本発明に使用される二重素管は第１図に示すご
ときもので、本図において、炭素鋼または低合金鋼の母
材管１の内部にステンレス鋼、ニツケルあるいはニツケ
ル合金等の合材管２が嵌入されている。この二重素管の
両端部は軸方向に長さｓだけ合材管２の外周と母材管３
の内周とが完全に密着されている。この時の密着部の長
さｓと合材管２の外径Ｄとの関係はｓゝ呈である。また
前記二重素管の両端密着部以外の中間部における母材管
１の内径ｄと合材管２の外径Ｄとの差ｅは合材管２の外
径Ｄの１．４９６以下、好ましくは０．７９６以下であ
る。管端において母材管１と合材管２とは溶接部３によ
り強固に肉盛溶接される。本発明で規定した材料は、母
材として炭素鋼又は低合金鋼であるが、この材料は変態
温度（約８５０℃）以下では体心立方格子構造であり、
熱膨脹係数は成分によＷ’ほぼ一定（１卜１３×１０ア
℃）である。変態点では体心立方格子から面心立方格子
に結晶構造が変化し、体積収縮するがそれ以上では他の
面心立方格子の金属とほぼ等しい熱膨脹係数（ １７〜
２０×１０−σ／℃）を有する。一方合材として規定し
たステンレス鋼、ニツケルおよびニツケル合金はいずれ
も室温から高温まで面心立方格子を保つ。熱膨脹係数は
、室温近くでは材質の違いによる差があるが、３００℃
以上ではいずれもほぼ等しい熱膨脹係数を有する。室温
での熱膨脹係数の大きい材質はステンレス鋼であわ、特
許請求範囲に記載される間隙差の上限はこの材質を基に
算出したものであるが、上記理由により他の材質でもこ
の間隙差はほとんど変化しない。室温での熱膨脹率の小
さいニツケルを使用の場合でほぼ１．２チ程度である。
これらの事は実験的にも確認されている。That is, the double blank tube used in the present invention is as shown in FIG. 1, in which a composite material such as stainless steel, nickel, or nickel alloy is placed inside a base material tube 1 of carbon steel or low alloy steel. Pipe 2 is inserted. Both ends of this double raw pipe are axially connected by a length s between the outer periphery of the composite pipe 2 and the base material pipe 3.
The inner periphery of At this time, the relationship between the length s of the close contact portion and the outer diameter D of the composite pipe 2 is sゝ. Further, the difference e between the inner diameter d of the base material pipe 1 and the outer diameter D of the composite pipe 2 at the intermediate portion other than the close contact portions at both ends of the double raw pipe is 1.496 or less of the outer diameter D of the composite pipe 2; Preferably it is 0.796 or less. At the tube end, the base material tube 1 and the composite material tube 2 are firmly overlay-welded by a welding portion 3. The material specified in the present invention is carbon steel or low alloy steel as the base material, but this material has a body-centered cubic lattice structure below the transformation temperature (approximately 850°C),
The coefficient of thermal expansion is approximately constant W' (13×10° C. per liter) depending on the components. At the transformation point, the crystal structure changes from a body-centered cubic lattice to a face-centered cubic lattice, and the volume shrinks, but beyond that point, the coefficient of thermal expansion is almost the same as that of other metals with a face-centered cubic lattice (17~
20×10-σ/°C). On the other hand, stainless steel, nickel, and nickel alloys specified as composite materials all maintain a face-centered cubic lattice from room temperature to high temperature. The coefficient of thermal expansion varies depending on the material near room temperature, but at 300℃
All of the above have approximately the same coefficient of thermal expansion. A material with a large coefficient of thermal expansion at room temperature is stainless steel, and the upper limit of the gap difference stated in the claims was calculated based on this material, but for the above reasons, this gap difference is almost the same even with other materials. It does not change. When using nickel, which has a small coefficient of thermal expansion at room temperature, the coefficient of thermal expansion is approximately 1.2 inches.
These things have also been confirmed experimentally.

この二重素管を圧延してパイプクラツド鋼を製造する熱
間圧延帰の種類としては、傾斜ロール穿孔圧延機プラグ
圧延機、マンドレル圧延機、アツセル圧延機が適してお
わ圧延温度は、８５０℃から１３００℃の温度が好まし
い。Suitable hot rolling methods for rolling this double blank pipe to produce pipe clad steel include inclined roll perforation mill, plug mill, mandrel mill, and Atsel rolling mill, and the rolling temperature is 850°C. Temperatures between 1300°C and 1300°C are preferred.

圧下率は、パイプクラツド鋼の圧着率に及ぼす影響が極
めて大きく、１回の圧延で少くとも１５９６以上に圧延
することが望ましく、好ましくは２０チ以上の圧下率を
とれば非常に圧着率の良いパイプクラツド鋼を得ること
ができる。本発明における組合せ二重素管は、約８５０
℃（母材管のオーステナイトイと温度）以上に加熱され
た場合母材管と合材管とには、合材管の方が（ｉ）熱膨
脹係数の差から約０．４％、さらに（Ｉｉ）母材のα→
ｒ変態により約０．３９６だけ大きい熱歪が発生する。The rolling reduction has a very large effect on the crimp rate of pipe clad steel, and it is desirable to roll it to at least 1596 mm or more in one rolling, and preferably a rolling rate of 20 inches or more will result in a pipe clad with a very good crimp rate. You can get steel. The combined double pipe in the present invention is approximately 850
When heated above ℃ (the temperature of the austenite of the base material pipe), the base material pipe and the composite pipe are approximately 0.4% higher due to the difference in thermal expansion coefficient (i), and ( Ii) α of base material →
The r-transformation generates a thermal strain that is approximately 0.396 larger.

さらに、急速加熱時には、両端部の昇温が速いので、両
端部の変形抵抗が他に比べ小さくなわ、そのため変形が
両端部に集中して溶接部破断の原因となつている。本発
明の効果は、この溶接部破断を完全に防止したことであ
る。Furthermore, during rapid heating, the temperature rises quickly at both ends, so the deformation resistance at both ends is smaller than at the other ends, which causes deformation to concentrate at both ends, causing breakage of the weld. The effect of the present invention is that this weld breakage is completely prevented.

すなわち合材管は加熱により母材管より大きな熱歪が発
生するが、両端部では両管が密着しているため径方向の
変形が拘束されるので大きな面圧力Ｆが発生する。この
面圧力Ｆによるまさつ力μＦは軸方向の変形の阻止力と
して作用する。この軸方向の変形が拘束される条件は、
つぎの通りである。That is, the composite pipe undergoes a larger thermal strain than the base material pipe due to heating, but since the two pipes are in close contact with each other at both ends, deformation in the radial direction is restrained, so a large surface pressure F is generated. The vertical force μF due to this surface pressure F acts as a force to prevent deformation in the axial direction. The conditions under which this axial deformation is constrained are:
It is as follows.

通常加熱中におけるまさつ係数μは約１．０と考えられ
るので、密着部長さＳがＤ／２以上である本発明の密接
二重管は、溶接部破断を防止できるのである。Since the thermal coefficient μ during normal heating is considered to be about 1.0, the close-contact double pipe of the present invention, in which the length S of the close-fitting portion is D/2 or more, can prevent breakage of the welded portion.

さらに上記について、第２図および第３図を参照して説
明する。Further, the above will be explained with reference to FIGS. 2 and 3.

合合材管に発生する軸方向応力０ｔ１周方向応力を０θ
とすると、本発明で考える条件では０ｔ１０，とも降伏
応力０Ｙに達していると考えられ、実験に訃いても確認
されたいるのでしたがつて、合材管の熱応力で軸方向に
発生する力Ｆｔはつぎのように表わされる。The axial stress generated in the composite pipe is 0t1, and the circumferential stress is 0θ.
Therefore, under the conditions considered in the present invention, it is thought that the yield stress reaches 0Y at both 0t10 and this was confirmed in experiments. Therefore, the force generated in the axial direction due to thermal stress in the composite pipe Ft is expressed as follows.

一方、合材管の膨脹により発生する面圧力Ｆはつぎのよ
うに表わされる。On the other hand, the surface pressure F generated by the expansion of the composite pipe is expressed as follows.

面圧力によるまさつ力はμＦで表わされるので軸方向の
変形が拘束される条件はつぎのように考えられる。Since the force due to surface pressure is expressed in μF, the conditions under which axial deformation is restricted can be considered as follows.

（２）、（８）式を（４）式に代入し、 σｔ＝σθ＝０Ｙとおくと Ｓ＼Ｄ／２μ （５Ｙが導びかれる。Substituting equations (2) and (8) into equation (4), If we set σt=σθ=0Y S\D/2μ (5Y is derived.

合材管の軸方向の変形が拘束された場合、合材管の径方
向の歪はその分だけ大きくなジ結局熱歪により約１．４
％母材管より大きな径膨脹が生ずるが、本発明では母材
管と合材管との間隙は直径差で１．４％以下にしてある
ため母材管と合材管とは密着状態に至る。When the axial deformation of the composite pipe is restrained, the radial strain of the composite pipe becomes correspondingly large.In the end, the thermal strain causes approximately 1.4
%, a larger diameter expansion occurs than the base material pipe, but in the present invention, the gap between the base material pipe and the composite material pipe is set to 1.4% or less in terms of diameter difference, so the base material pipe and the composite material pipe are in close contact. reach.

この状態で一定時間加熱されると、接合面における拡散
接合が進行し、ある程度の強加工に耐え得る接合強度が
得られる。しかしこの接合強度は、爆着クラツド鋼の接
合強度に比較すると低く、擬似接着に近いものであり、
爆着パイプクラツド鋼を圧延した場合に発生する、部分
的圧着に起因する合材のしわ発生等の危険は少なく、熱
間圧延により全面一様な圧着クラツド鋼を得ることがで
きる。つぎに実施例について説明する。When heated in this state for a certain period of time, diffusion bonding at the bonding surfaces progresses, and a bonding strength that can withstand some degree of severe processing is obtained. However, this bonding strength is low compared to that of explosive bonded clad steel, and is close to pseudo-bonding.
There is little risk of wrinkling of the composite material due to partial crimping, which occurs when explosion-bonded pipe clad steel is rolled, and it is possible to obtain crimped clad steel that is uniform over the entire surface by hot rolling. Next, examples will be described.

ノ〔実施例 １〕 外径２１０１１１１肉厚３０ｍ１！、長さ２２００ｍ１
！Ｌの炭素鋼管の内面を５μの荒さにハブ研磨し母材管
とした。[Example 1] Outer diameter 2101111, wall thickness 30m1! , length 2200m1
! The inner surface of the L carbon steel pipe was hub-polished to a roughness of 5 μm and used as a base material pipe.

一方、外径１４０ｍｍ１肉厚１０ｍ１１長さ２２６０ｍ
ｍ（７）ＳＵＳ３ｌ６Ｌステンレス鋼管を溶体化処理し
、外面を５μの荒さにハブ研磨し、５０μ厚さにニツケ
ルメツキをし合材管とした。つぎに母材管に合材管を挿
入組合せ、合材管の両端部の密着部の長さＳ＝１００１
ｍとして拡管して、母材管に密接させた後、端部を全周
にわたつてステンレスの溶接棒で母材管と合材管とを強
固に肉盛溶接した。さらに合材管に内圧を加えて母材管
と合材管との隙間を直径差で合材管外径の１．４％以下
になるよう拡管成形し二重素管を作成した。その後、片
方の溶接部に５ｍ１径のキリで２つの孔をあけ空気排出
孔とした。これを１２５０℃で１時間加熱後、空気孔の
ない方から穿孔圧延機で一気に肉厚１５１１１外径２２
０ｍ１に圧延した。得られたパイプクラツド鋼の両端を
２００１１１切断した後超音波探傷法で圧着状況を調査
した結果、１００％の面積が圧着状態であることが確認
された。〔実施例２〕 外径２１０ｍ１！Ｌ１肉厚３０′！１Ｅｍ１長さ２．２
００ｍｍの炭素鋼管の内面を５μの荒さにハブ研磨し母
材管とした。On the other hand, outer diameter 140mm1 wall thickness 10m11 length 2260m
m(7) SUS3l6L stainless steel pipe was solution treated, the outer surface was hub polished to a roughness of 5μ, and nickel plated to a thickness of 50μ to make a composite pipe. Next, the composite material pipe is inserted into the base material pipe and combined, and the length of the close contact part at both ends of the composite material pipe is S = 1001
After expanding the pipe to a diameter of 1.5 m and bringing it into close contact with the base material pipe, the base material pipe and the composite material pipe were firmly overlay-welded using a stainless steel welding rod over the entire circumference of the end. Further, internal pressure was applied to the composite pipe to expand the pipe so that the gap between the base material pipe and the composite pipe was 1.4% or less of the outside diameter of the composite pipe in terms of diameter difference, thereby creating a double base pipe. Thereafter, two holes with a diameter of 5 m1 were drilled in one of the welded parts to serve as air exhaust holes. After heating this at 1250℃ for 1 hour, it was rolled at once using a piercing rolling machine from the side without air holes to a wall thickness of 15111 and an outer diameter of 22.
It was rolled to 0ml. After cutting both ends of the obtained pipe clad steel, the crimping condition was investigated using ultrasonic flaw detection, and it was confirmed that 100% of the area was crimped. [Example 2] Outer diameter 210m1! L1 wall thickness 30'! 1Em1 length 2.2
The inner surface of a 00mm carbon steel pipe was hub-polished to a roughness of 5μ to obtain a base material pipe.

一方、外径１４０Ｊｍ１１肉厚１０１１ｍ１１長さ２．
２６０ｍｍのニツケル管を、外面を５μの荒さにハブ研
磨し合材管とした。つぎに母材管に合材管を挿入組合せ
、合材管の両端部の密着部の長さＳ＝１００１ｔ１１Ｌ
として拡管して、母材管に密接させた後、端部を全周に
わたつてステンレスの溶接棒で母材管と合材管とを強固
に肉盛溶接した。さらに合材管に内圧を加えて母材管と
合材管との隙間を直径差で合材管外径の１．４％以下に
なるよう拡管成形し二重素管を作成した。その後、片方
の溶接部に５ｎ径のキリで２つの孔をあけ空気排出孔と
した。On the other hand, outer diameter 140Jm11 wall thickness 1011m11 length 2.
A 260 mm nickel tube was hub-polished to a roughness of 5 μm on the outer surface to make a composite tube. Next, insert the composite material pipe into the base material pipe and combine, the length of the close contact part at both ends of the composite material pipe S = 1001t11L
After expanding the tube and bringing it into close contact with the base material tube, the base material tube and composite material tube were firmly overlaid welded using a stainless steel welding rod around the entire circumference of the end. Further, internal pressure was applied to the composite pipe to expand the pipe so that the gap between the base material pipe and the composite pipe was 1.4% or less of the outside diameter of the composite pipe in terms of diameter difference, thereby creating a double base pipe. Thereafter, two holes were made in one of the welded parts using a 5n diameter drill to serve as air exhaust holes.

これを１２５０℃で１時間加熱後、空気孔のない方から
穿孔圧延機で一気に肉厚１５１Ｅ）外径２２０ｎに圧延
した。得られたパイプクラツド鋼の両端を２００露ｌ切
断した後超音波探傷法で圧着状況を調査した結果、１０
０％の面積が圧着状態であることが確認された。〔実施
例 ３〕 外径２１０Ｕ、肉厚３０ｎ）長さ２，２００Ｕの炭素鋼
管の内面を５μの荒さにハブ研磨し母材管とした。After heating this at 1250° C. for 1 hour, it was rolled at once using a piercing mill from the side without air holes to a thickness of 151E) and an outer diameter of 220N. After cutting 200 l of both ends of the obtained pipe clad steel, we investigated the crimping condition using ultrasonic flaw detection, and found that 10
It was confirmed that 0% of the area was in a crimped state. [Example 3] The inner surface of a carbon steel pipe with a length of 2,200 U (outer diameter 210 U, wall thickness 30 n) was hub-polished to a roughness of 5 μm to obtain a base material pipe.

一方、外径１４０ｎ）肉厚１０ｎ）長さ２，２６０ｎの
ニツケル合金（キユプロニツケル）管を外面を５μの荒
さにハブ研磨し合材管とした。つぎに母材管に合材管を
挿入組合せ、合材管の両端部の密着部の長さＳ＝１００
ｎとして拡管して、母材管に密接させた後、端部を全周
にわたつてステンレスの溶接棒で母材管と合材管とを強
固に肉盛溶接した。さらに合材管に内圧を加えて母材管
と合材管との隙間を直径差で合材管外径の１．４％以下
になるよう拡管成形し二重素管を作成した。その後、片
方の溶接部に５Ｕ径のキリで２つの孔をあけ空気排出孔
とした。これを１２５０℃で１時間加熱後、空気孔のな
い方から穿孔圧延機で一気に肉厚１５ｎ）外径２２０ｎ
に圧延した。得られたパイプクラツド鋼の両端を２００
ｎ切断した後超音波探傷法で圧着状況を調査した結果、
１００チの面積が圧着状態であることが確認された。一
方比較のため、上記と同一寸法の素管２組を用意し、上
記と同一の表面処理をした。On the other hand, a nickel alloy (Cupronickel) tube having an outer diameter of 140 nm, a wall thickness of 10 nm, and a length of 2,260 nm was hub-polished to a roughness of 5 μm on the outer surface to obtain a composite pipe. Next, insert the composite material pipe into the base material pipe and combine, and the length of the close contact part at both ends of the composite material pipe is S = 100
After expanding the tube as n and bringing it into close contact with the base material tube, the base material tube and the composite material tube were firmly overlay welded using a stainless steel welding rod over the entire circumference of the end. Further, internal pressure was applied to the composite pipe to expand the pipe so that the gap between the base material pipe and the composite pipe was 1.4% or less of the outside diameter of the composite pipe in terms of diameter difference, thereby creating a double base pipe. Thereafter, two holes were made in one of the welded parts using a 5U diameter drill to serve as air exhaust holes. After heating this at 1250℃ for 1 hour, it was rolled at once using a piercing rolling machine starting from the side without air holes (thickness 15n) and outer diameter 220n.
Rolled to . Both ends of the obtained pipe clad steel were
As a result of investigating the crimping condition using ultrasonic flaw detection after cutting,
It was confirmed that an area of 100 inches was in a crimped state. On the other hand, for comparison, two sets of raw tubes with the same dimensions as above were prepared and subjected to the same surface treatment as above.

一組目のパイプは、合材の両端部の密着部の長さＳ＝３
０ＥＲとして拡管し、母材管と密接させた後両端部を全
周にわたつてステンレスの溶接棒で両管を強固に溶接し
た。For the first set of pipes, the length of the joint at both ends of the composite material is S = 3
After expanding the tube as 0ER and bringing it into close contact with the base metal tube, both ends were firmly welded around the entire circumference with a stainless steel welding rod.

以後上記の実施例と同一方法で二重素管を作成し、熱間
圧延した。得られたパイプクラツド鋼は、両端２００Ｕ
切断後超音波探傷法で圧着状況を検査した結果、両端部
に不着部が認められ、接着面積は約８５９６であつた。
二組目のパイプについては、ステンレス管を単に挿入し
た状態で両端部で再管を肉盛溶接した後、空気孔を設け
て、上記と同一の条件で熱間圧延した。得られたパイプ
クラツド鋼の両端を２００Ｕ切断して、超音波深傷法で
圧着状況を調査した結果圧延開始側に６００１町圧延終
了側に２００ｎの長さの不着部が認められた。以上の通
ク本発明の方法は極めて優れていることが確認された。Thereafter, a double blank tube was produced in the same manner as in the above example and hot rolled. The obtained pipe clad steel has 200U on both ends.
After cutting, the crimped state was inspected using ultrasonic flaw detection, and as a result, non-bonded areas were found at both ends, and the bonded area was about 8,596.
For the second set of pipes, the stainless steel pipes were simply inserted and the pipes were overlay-welded at both ends, air holes were provided, and hot rolled under the same conditions as above. Both ends of the obtained pipe clad steel were cut by 200 U, and the crimping condition was investigated using the ultrasonic deep damage method. As a result, a non-bonded part of 6001 mm length was observed on the rolling start side and 200 nm long on the rolling end side. It has been confirmed that the method of the present invention described above is extremely excellent.

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

第１図本発明に使用する二重素管の説明縦断面図である
。 第２図および第３図はそれぞれ本発明における両端部の
面圧力説明のための縦断面および横断面図である。１
・・・・・・母材管、２−・・・・・合材管、３・・・
・・・溶接部。FIG. 1 is an explanatory longitudinal sectional view of a double pipe used in the present invention. FIG. 2 and FIG. 3 are a longitudinal cross-sectional view and a cross-sectional view, respectively, for explaining the surface pressure at both ends in the present invention. 1
...Base material pipe, 2-...Mixture material pipe, 3...
···welded part.

Claims (1)

【特許請求の範囲】[Claims] １ 炭素鋼または低合金鋼を母材管とし、その内部にス
テンレス鋼、ニッケルあるいはニッケル合金などの合材
管を嵌入して二重素管とし、この二重素管の両端におい
て母材管と合材管とを溶接した後熱間圧延してパイプク
ラッド鋼を製造する方法において、前記二重素管の両端
部において母材管内面と合材管外面とを密着させ、この
密着部の軸方向の長さを前記合材管外径の１／２以上と
し、また前記密着部以外の二重素管中間部において母材
管内面と合材管外面との間隙を直径差で合材管外径の１
．４％以下にした二重素管を使用することを特徴とする
パイプクラッド鋼の製造方法。1 Carbon steel or low-alloy steel is used as the base material pipe, and a composite material pipe such as stainless steel, nickel, or nickel alloy is inserted inside to form a double base pipe, and both ends of this double base pipe are connected to the base material pipe. In a method of manufacturing pipe clad steel by hot rolling after welding a composite pipe, the inner surface of the base material pipe and the outer surface of the composite pipe are brought into close contact with each other at both ends of the double base pipe, and the axis of this contact part is The length in the direction is 1/2 or more of the outer diameter of the composite pipe, and the gap between the inner surface of the base material pipe and the outer surface of the composite pipe at the middle part of the double blank pipe other than the close contact part is determined by the diameter difference. 1 of the outer diameter
．． A method for manufacturing pipe clad steel, characterized by using a double base pipe with a content of 4% or less.