JPS6317890B2 - - Google Patents
Info
- Publication number
- JPS6317890B2 JPS6317890B2 JP13987379A JP13987379A JPS6317890B2 JP S6317890 B2 JPS6317890 B2 JP S6317890B2 JP 13987379 A JP13987379 A JP 13987379A JP 13987379 A JP13987379 A JP 13987379A JP S6317890 B2 JPS6317890 B2 JP S6317890B2
- Authority
- JP
- Japan
- Prior art keywords
- welding
- steel
- temperature
- present
- steel pipe
- 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.)
- Expired
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 53
- 239000010959 steel Substances 0.000 claims description 53
- 238000010438 heat treatment Methods 0.000 claims description 33
- 229910052759 nickel Inorganic materials 0.000 claims description 23
- 238000004519 manufacturing process Methods 0.000 claims description 21
- 230000006698 induction Effects 0.000 claims description 7
- 238000010791 quenching Methods 0.000 claims description 5
- 230000000171 quenching effect Effects 0.000 claims description 3
- 238000005496 tempering Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 2
- 238000003466 welding Methods 0.000 description 45
- 238000000034 method Methods 0.000 description 40
- 238000001816 cooling Methods 0.000 description 18
- 239000010410 layer Substances 0.000 description 9
- 239000010953 base metal Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 239000002356 single layer Substances 0.000 description 4
- 238000012733 comparative method Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000011324 bead Substances 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000010606 normalization Methods 0.000 description 2
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000010897 surface acoustic wave method Methods 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Butt Welding And Welding Of Specific Article (AREA)
- Heat Treatment Of Articles (AREA)
Description
本発明は、3.5％Ni大径鋼管の製造方法に係り、
更に具体的に言えば、熱間圧延ままの3.5％Ni鋼
板をUO方式その他の方法により管状に成形し、
そのシーム部を内外面から各々一層盛り溶接した
のち、該鋼管を誘導加熱によつてA3点以上に加
熱、焼入れし、次いでA1点以下で焼戻すことに
よつて、母材、溶接部とも低温性能が優れてい
て、例えば−101℃における仕様を十分に満足す
る輸送配管に適した3.5％Ni大径（直径16インチ
以上をいう）鋼管を、能率的にしかも歪等の少な
い精度の優れた鋼管として製造せんとするもので
ある。
一般に3.5％Ni鋼は、低温靭性の優れた鋼とし
て広く知られている。そして、ASTM規格では、
Ａ−203に鋼板が、又Ａ−333及びＡ−671に鋼管
が夫々規格化されていて、Ｃ：0.23％以下、Si：
0.13〜0.32％、Mn：0.8％以下、Ｐ：0.035％以
下、Ｓ：0.04％以下、Ni：3.18〜3.82％、残部鉄
及び不可避不純物からなる組成を有し、熱処理と
しては焼準が規定されている。この鋼板は、−100
℃近傍で良好な強度と靭性を有することから、エ
タン（−88.5℃）、アセチレン（−84℃）、炭酸ガ
ス（−78.5℃）等の液化ガスを貯蔵する常圧低温
タンクに使用されており、それらの配管には上記
の3.5％Ni鋼管を用いるのが適切であるとされて
いる。
しかして、上記のASTM規格に基づいて鋼管
の直径（外径）が16インチ以上のいわゆる大径の
3.5％Ni鋼管を製造しようとすると、
焼準処理を施した3.5％Ni鋼板を管状に成形
し溶接する方法。
熱間圧延ままの3.5％Ni鋼板を管状に成形後
溶接を行い、できた鋼管全体（母材部及び溶接
部）を焼準する方法。
の２つの方法が採り得る。しかしながら、上記
の方法は、いずれも下記の如き問題がある。
即ち、上記の方法によつて3.5％Ni大径鋼管
を製造した場合、母材部の靭性は問題がないが、
溶接部の靭性に問題がある。そこで、この溶接部
の問題を解消する溶接手段をとると製造能率が下
り、この製造能率の上るような溶接手段をとると
又溶接部の靭性に問題が出るということであつ
た。このことを更に説明すると、従来3.5％Ni鋼
の溶接にあつては、被覆溶接棒を用いる小入熱に
よる多層盛溶接をするが、或いは小電流のMIG
による多層盛り溶接をするかの、いずれかが行わ
れている。これらの溶接が行われた場合には、溶
接部は微細なフエライト均一組織となり、下層ビ
ードが上層ビードによりTemper（焼戻）される
ことも手伝つて一応十分な靭性を有していたが、
近時の大径鋼管製造時に採用されているサブマー
ジアーク溶接法等に比して10〜15倍の手数、時間
がかかるために製造能率が低く、一方この点を改
善するために前記のサブマージアーク溶接法を採
用すると、この溶接法では入熱量が上記の従来方
法の多層盛溶接とは比較にならないほど多いので
溶接部の靭性が劣化するという問題があり、従つ
て、低温靭性を重視する3.5％Ni鋼では内外両面
各一層盛り溶接は到底考えられないことであつ
た。
又、上記の方法は、溶接後管全体を焼準する
ので、たとえ上記溶接に内外面各一層盛り溶接を
行つたとしても熱影響部を含めた溶接部も、焼準
処理により組織が微細化されるので低温靭性の点
では問題はないが、焼準処理における加熱保持段
階並びにこれに続く空冷中に、大径鋼管なるがゆ
え、かなりの重量を持つた管状体が、高温下に併
も長時間曝されることになるので、潰れたような
形になつて真円度が損われ、又管の内外面の冷却
速度差から、製造された管に歪みを生じ、寸法精
度上の問題があつた。
本発明は、上記の諸問題を悉く解決した3.5％
Ni大径鋼管の製造方法を提供するものであつて、
熱間圧延ままの3.5％Ni鋼板を管状に成形し、成
形された該管状物のシーム部を管内外面から各々
一層盛り溶接して鋼管とし、これを誘導加熱によ
つてA3点以上の温度に加熱して焼入れし、次い
でA1点以下の温度で焼戻すことを特徴とするも
のである。
次に、本発明の製造方法について詳細に説明す
る。本発明で言う3.5％Ni鋼とは、前記ASTM規
格に定められた組成を有するものであつて、何ら
特殊なものではない。前記した元素の他に、この
種の鋼に通常脱酸剤または結晶粒度調整用として
広く用いられているAlを0.01〜0.1％程度含有し
てよいことは勿論である。鋼板の板厚は特に限定
されないが大径鋼管用として通常用いられる3.5
％Ni鋼板は、板厚が５mm〜１インチ（25.4mm）の
ものである。管状に成形する方法も特に限定され
ずUO方式、スパイラル方式、プレスベンド方式
のいずれの方式で成形してもよく、また複数のロ
ールを用いて成形してもよい。本発明ではここで
用いる3.5％Ni鋼板を熱間圧延ままとしたことの
理由は、この管状成形の後シーム部溶接をしたの
ち管全体を熱処理する工程があるから、成形前に
熱処理する意味がないことと、3.5％Ni鋼板は熱
間圧延ままでも成形が容易なことによる。さて、
管状に成形された後の管のシーム部を溶接するに
当つて、本発明では既に説明した大径鋼管の製造
に近時採用されている内外面各一層盛り溶接を行
う。この溶接法は、一般の大径鋼管の溶接におい
ては殆んどサブマージドアーク溶接法によつてい
る。本発明ではこのサブマージドアーク溶接法は
勿論、本発明の出願人が先に提案した特開昭51−
61452号及び特開昭51−61453号の大電流MIG溶
接法を採用することも可能である。
本発明において上記の内外面各一層盛り溶接を
採用したことの理由は、先に説明した如く低温靭
性を重視する3.5％Ni鋼の溶接にあつては、手溶
接、或いはミグ溶接による小入熱の多層盛り溶接
することが常識であるが、既述のように極めて非
能率的である。そこで、本発明では溶接部の靭性
劣化が懸念されるような大入熱の内外面各一層盛
り溶接を採用することにより製造能率を低下させ
ないことを目標の一つとし、この場合に懸念され
る靭性劣化に対しては後工程に熱処理をすること
とした。なお、本発明の構成としては、シーム部
溶接の後直ちに熱処理することになつているけれ
ども、溶接後鋼管の形状を矯正する拡管工程を入
れてもよいことは言うまでもない。
また、本発明において熱処理条件を上記の如く
限定した理由は、本発明の製造方法の対象として
いる大径鋼管とは、直径（外径）が16インチ以上
のものを指しているので、この寸法が熱処理条件
と密接不可分の関係にある。即ち、直径が16イン
チ以上の鋼管ではA3点以上の温度域に長時間置
くと鋼が軟化することと、大寸法の中空部材が自
重によつてだれることにより、管形が変形して寸
法精度が出ない。そこで、熱処理に当つてはA3
点以上の所定温度まで急速に加熱すると共に、冷
却にあつても冷却開始温度からA3点までを急速
に冷却する必要がある。
発明者らは、実験により直径16インチ以上の大
径鋼管をA3点以上の温度域に一定時間以上置く
と、管体の変形が著しくなることを見出し、これ
に対処するために、本発明ではA3点以上の所定
温度まで急速加熱し、次いで焼入れ（水焼入れ）
処理するものである。そして前記急速加熱に当つ
ては、一般の加熱炉では被加熱物は炉内の熱の伝
導、輻射、対流によつて昇温するので時間がかか
り過ぎるので、被加熱物自体が発熱する誘導加熱
とした。なお、焼入れ処理のままでは靭性が得ら
れないので通常行われているA1点以下の温度で
焼戻すものとする。
冷却について見るに、ASTM規格では3.5％Ni
鋼管の熱処理として焼準即ちA3点以上の温度か
ら空冷することを定めているが、本発明の対象と
している直径16インチ以上の大径鋼管ではこの空
冷による冷却では、冷却速度が非常に緩慢過ぎ
て、たとえ加熱段階で誘導加熱によりA3点→所
定加熱温度までの加熱時間が短縮されたとして
も、所定加熱温度→A3点までの冷却時間が長く
かかつたのでは、結果として管体の潰れ、曲り現
象が避けられず、熱処理後許容寸法精度内に入れ
るため矯正しなければならない。つまり、A3点
→所定加熱温度→A3点のトータル時間がこの場
合問題なのであつて、加熱時と同様に冷却時にも
急速冷却が必要である。
尚、誘導加熱によつて熱処理する場合は、一般
の炉加熱の場合よりも加熱が急速であり、保持時
間もとり難いので、加熱温度を高くする必要があ
り、必然的に加熱温度一冷却開始温度−A3点ま
での冷却の所要時間は長くなる傾向にあり、ここ
を急冷する重要性は一層大きくなる。
本発明の製造方法においては、上記の熱処理に
よつて鋼管の母材部は勿論、溶接部も焼戻しマル
テンサイトとなり、焼準を行つた場合よりも母材
部、溶接部共に−101℃仕様に適した低温靭性の
優れた3.5Ni大径鋼管を製造することができる。
次に、本発明の製造方法の実施例と従来の製造
方法による比較例を示す。
The present invention relates to a method for manufacturing a 3.5% Ni large diameter steel pipe,
More specifically, a hot-rolled 3.5% Ni steel plate is formed into a tubular shape using the UO method or other methods.
After welding the seam in one layer from the inner and outer surfaces, the steel pipe is heated and quenched by induction heating to a point A of 3 or more, and then tempered to a point A of 1 or less. For example, 3.5% Ni large-diameter (16 inches or more in diameter) steel pipe, which satisfies specifications at -101°C and is suitable for transportation piping, can be manufactured efficiently and accurately with less distortion. It is intended to be manufactured as an excellent steel pipe. In general, 3.5% Ni steel is widely known as a steel with excellent low-temperature toughness. And according to ASTM standards,
A-203 is standardized for steel plates, and A-333 and A-671 are standardized for steel pipes, C: 0.23% or less, Si:
It has a composition of 0.13 to 0.32%, Mn: 0.8% or less, P: 0.035% or less, S: 0.04% or less, Ni: 3.18 to 3.82%, the balance being iron and unavoidable impurities, and normalizing is specified as the heat treatment. ing. This steel plate is −100
Because it has good strength and toughness near ℃, it is used in atmospheric pressure low temperature tanks that store liquefied gases such as ethane (-88.5℃), acetylene (-84℃), and carbon dioxide (-78.5℃). It is considered appropriate to use the above-mentioned 3.5% Ni steel pipes for these pipes. However, based on the above ASTM standards, so-called large diameter steel pipes with a diameter (outer diameter) of 16 inches or more are
When trying to manufacture 3.5% Ni steel pipes, the method involves forming normalized 3.5% Ni steel plates into a tubular shape and welding them. A method in which hot-rolled 3.5% Ni steel sheets are formed into a tubular shape and then welded, and the entire resulting steel pipe (base metal and welded part) is normalized. There are two possible methods. However, all of the above methods have the following problems. In other words, when a 3.5% Ni large-diameter steel pipe is manufactured by the above method, there is no problem with the toughness of the base material, but
There is a problem with the toughness of the weld. Therefore, if a welding method is used to solve this problem of the welded part, the manufacturing efficiency decreases, and if a welding method is used that increases the manufacturing efficiency, a problem arises in the toughness of the welded part. To explain this further, conventional welding of 3.5%Ni steel involves multi-layer welding using a coated welding rod with low heat input, or MIG welding with low current.
Either multi-layer welding or multi-layer welding is performed. When these welds were performed, the welded part had a fine ferrite uniform structure and had sufficient toughness, partly due to the fact that the lower bead was tempered by the upper bead.
Compared to submerged arc welding, which is currently used in the production of large-diameter steel pipes, it takes 10 to 15 times more labor and time, resulting in lower manufacturing efficiency. When this welding method is adopted, there is a problem that the toughness of the welded part deteriorates because the amount of heat input in this welding method is incomparably greater than that of the conventional multilayer welding method described above.Therefore, low temperature toughness is emphasized. %Ni steel, single-layer welding on both the inner and outer surfaces was completely unthinkable. In addition, in the above method, the entire tube is normalized after welding, so even if one-layer welding is performed on the inner and outer surfaces, the structure of the welded area, including the heat-affected zone, will be refined by the normalization treatment. However, during the heating and holding stage of normalizing treatment and the subsequent air cooling, the tubular body, which has a considerable weight due to its large diameter, is exposed to high temperatures. Because it is exposed for a long time, it becomes a crushed shape and loses roundness, and the difference in cooling rate between the inner and outer surfaces of the tube causes distortion in the manufactured tube, causing problems with dimensional accuracy. It was hot. The present invention solves all the above problems by 3.5%.
Provides a method for manufacturing Ni large diameter steel pipe,
A hot-rolled 3.5% Ni steel plate is formed into a tube shape, and the seam of the formed tube is welded in one layer from the inner and outer surfaces of the tube to form a steel tube, which is then heated to a temperature of 3 points A or higher by induction heating. It is characterized by being heated to and quenched, and then tempered at a temperature below A1 point. Next, the manufacturing method of the present invention will be explained in detail. The 3.5% Ni steel referred to in the present invention has a composition specified in the ASTM standard and is not special at all. Of course, in addition to the above-mentioned elements, about 0.01 to 0.1% of Al, which is commonly used as a deoxidizer or for grain size adjustment in this type of steel, may be contained. The thickness of the steel plate is not particularly limited, but 3.5 is usually used for large diameter steel pipes.
%Ni steel plate has a thickness of 5 mm to 1 inch (25.4 mm). The method of forming into a tubular shape is not particularly limited, and may be formed by any of the UO method, spiral method, and press bend method, or may be formed using a plurality of rolls. In the present invention, the reason why the 3.5% Ni steel plate used here is left as hot rolled is that after this tubular forming, there is a process of welding the seam and then heat treating the entire tube, so there is no point in heat treating it before forming. This is because 3.5% Ni steel sheets are easy to form even when hot rolled. Now,
In welding the seam portions of the pipe after it has been formed into a tubular shape, the present invention performs one-layer welding on each of the inner and outer surfaces, which has recently been adopted in the production of large-diameter steel pipes as described above. This welding method is mostly based on the submerged arc welding method when welding general large diameter steel pipes. The present invention uses not only this submerged arc welding method, but also the submerged arc welding method proposed by the applicant of the present invention,
It is also possible to adopt the high current MIG welding method disclosed in No. 61452 and Japanese Patent Application Laid-Open No. 51-61453. The reason why the above-mentioned single-layer welding of the inner and outer surfaces is adopted in the present invention is that, as explained earlier, when welding 3.5% Ni steel, which emphasizes low-temperature toughness, the low heat input by manual welding or MIG welding is It is common knowledge to perform multi-layer welding, but as mentioned above, this is extremely inefficient. Therefore, one of the goals of the present invention is to avoid reducing manufacturing efficiency by employing single-layer welding on both the inner and outer surfaces with large heat input, which would cause concerns about deterioration of the toughness of the welded part. To prevent toughness deterioration, we decided to perform heat treatment in the post-process. Although the present invention is configured such that heat treatment is performed immediately after seam welding, it goes without saying that a pipe expansion process may be included to correct the shape of the steel pipe after welding. In addition, the reason for limiting the heat treatment conditions in the present invention as described above is that the large-diameter steel pipe targeted by the manufacturing method of the present invention refers to one with a diameter (outer diameter) of 16 inches or more. is closely and inseparably related to the heat treatment conditions. In other words, if a steel pipe with a diameter of 16 inches or more is left in a temperature range of A 3 or above for a long time, the steel will soften, and the large hollow member will sag under its own weight, causing the pipe shape to deform. Dimensional accuracy is not achieved. Therefore, for heat treatment, A 3
It is necessary to rapidly heat the material to a predetermined temperature above the point, and also to rapidly cool it from the cooling start temperature to point A3 . Through experiments, the inventors found that when a large-diameter steel pipe with a diameter of 16 inches or more is placed in a temperature range of A 3 or more for a certain period of time, the deformation of the pipe body becomes significant.To cope with this, the present invention was developed. Then, rapidly heat to a predetermined temperature of 3 points or higher, then quench (water quench)
It is something to be processed. In general heating furnaces, the temperature of the object to be heated increases through conduction, radiation, and convection of heat within the furnace, which takes too much time, so induction heating, in which the object itself generates heat, is used. And so. In addition, since toughness cannot be obtained if the steel is quenched, it should be tempered at a temperature below the A1 point, which is normally performed. Regarding cooling, the ASTM standard requires 3.5% Ni.
As a heat treatment for steel pipes, air cooling is specified from a temperature of 3 points or above, which is called normalization, but the cooling rate of large diameter steel pipes of 16 inches or more, which is the subject of this invention, is extremely slow when using air cooling. Even if the heating time from point A 3 to the specified heating temperature is shortened by induction heating in the heating stage, if the cooling time from the specified heating temperature to point A 3 is taken longer, as a result, the pipe The phenomenon of crushing and bending of the body is unavoidable, and it must be corrected to bring it within the allowable dimensional accuracy after heat treatment. In other words, the total time from three points A to the predetermined heating temperature to three points A is a problem in this case, and rapid cooling is required during cooling as well as during heating. In addition, when heat treatment is performed by induction heating, heating is more rapid than in the case of general furnace heating, and the holding time is also difficult to maintain, so the heating temperature must be raised, and inevitably the heating temperature - cooling start temperature -A The time required to cool down the three points tends to be longer, and the importance of rapid cooling at these points becomes even greater. In the manufacturing method of the present invention, not only the base metal part of the steel pipe but also the welded part becomes tempered martensite by the above heat treatment, and both the base metal part and the welded part have a -101℃ specification than when normalizing is performed. It is possible to manufacture 3.5Ni large-diameter steel pipes with suitable low-temperature toughness. Next, an example of the manufacturing method of the present invention and a comparative example of a conventional manufacturing method will be shown.
【表】【table】
【表】
上記第１表は本発明法の実施例に供給した3.5
％Ni鋼板と従来法による比較例に供試した3.5％
Ni鋼板の組成を示したものであり、第２表は
各々の製造プロセスを示したものである。
第２表中の溶接法のSAWはサブマージアーク
溶接法であり、MIGは前述の本発明の出願人が
先に提案した大電流MIG溶接法を指す。[Table] The above Table 1 provides 3.5
%Ni steel plate and 3.5% used for comparison with conventional method
Table 2 shows the composition of the Ni steel plate, and Table 2 shows the manufacturing process for each. The welding method SAW in Table 2 is a submerged arc welding method, and MIG refers to the high current MIG welding method previously proposed by the above-mentioned applicant of the present invention.
【表】【table】
【表】
上記第３表は本発明法及び従来法の実施例に採
用したSAW法の溶接条件を示したもので溶接条
件は両者同一である。第４表は同じく本発明法の
実施例に採用した前記大電流MIG溶接法の溶接
条件である。又、第１図は本発明法の実施例にお
ける焼入れ処理時の加熱、冷却の温度パターンを
示した線図であり、第２図は同じく焼戻し処理時
の加熱、冷却の温度パターンを示した線図であ
る。
上記の条件によつて製造された本発明の製造方
法の実施例による大径鋼管と従来の製造方法によ
る比較例の大径鋼管との母材部の機械的性質を第
５表に、同じく溶接部の機械的性質を第６表に示
した。[Table] Table 3 above shows the welding conditions of the SAW method adopted in the examples of the present invention method and the conventional method, and the welding conditions are the same for both. Table 4 shows the welding conditions for the high current MIG welding method, which was also adopted in the example of the method of the present invention. Furthermore, Fig. 1 is a line diagram showing the temperature pattern of heating and cooling during the hardening process in an embodiment of the method of the present invention, and Fig. 2 is a line diagram showing the temperature pattern of heating and cooling during the tempering process. It is a diagram. Table 5 shows the mechanical properties of the base metal parts of the large diameter steel pipe according to the example of the manufacturing method of the present invention manufactured under the above conditions and the large diameter steel pipe of the comparative example manufactured using the conventional manufacturing method. The mechanical properties of the parts are shown in Table 6.
【表】【table】
【表】
上記第５表、第６表から明らかなように、本発
明の製造方法による3.5％Ni大径鋼管は従来の製
造方法による大径鋼管と比べ、本発明法のSAW
溶接、大電流MIG溶接共に母材部、溶接部のい
ずれも機械的性質が優れ、特に−101℃における
低温靭性は溶接金属、HAZ（母材熱影響部）共本
発明によるものの方が優れていることが認められ
る。
又、管の寸法精度については、直径28インチ、
肉厚９mm、の大径鋼管を第１〜２図に示す本発明
の熱サイクルによつて焼入れ処理し、しかる後焼
戻し処理したものと、一方比較のためA3以上所
定温度までの昇降条件のみを第１図と同一とし、
その後の冷却を焼準（冷却条件１℃／sec）処理
としたもの（以下比較法という）を、各50本製造
し、各製品について寸法精度をチエツクした結
果、寸法精度を超えたものの最大寸法は、本発明
法では４mm、比較法では９mmであり、曲り（長さ
12ｍ）は本発明法では10mm、比較法では14mmであ
つた。このように、管の寸法精度においても、加
熱を誘導加熱とし、かつ焼入れ処理を施すことに
よつて、高温に曝す時間を少なくしたことから、
良好に保持され、又製造能率も従来の小入熱多層
盛り溶接を避け、大入熱による両面各一層盛り溶
接としたことにより、極めて高能率とすることが
できる。[Table] As is clear from Tables 5 and 6 above, the 3.5% Ni large-diameter steel pipe manufactured by the manufacturing method of the present invention has a higher SAW
In both welding and high-current MIG welding, both the base metal and welded parts have excellent mechanical properties, and in particular, the low-temperature toughness at -101°C is superior to the weld metal and HAZ (base metal heat affected zone) made by the present invention. It is recognized that there are Also, regarding the dimensional accuracy of the pipe, the diameter is 28 inches,
A large-diameter steel pipe with a wall thickness of 9 mm was quenched by the heat cycle of the present invention shown in Figures 1 and 2, and then tempered, and for comparison, only the lifting conditions of A 3 or higher to a predetermined temperature were used. is the same as in Figure 1,
We manufactured 50 pieces of each product using a normalizing process (cooling condition: 1°C/sec) for subsequent cooling (hereinafter referred to as the comparative method), and checked the dimensional accuracy of each product.As a result, we found that the maximum size of the products that exceeded the dimensional accuracy. is 4 mm in the method of the present invention and 9 mm in the comparative method, and the bending (length)
12 m) was 10 mm in the method of the present invention and 14 mm in the comparative method. In this way, the dimensional accuracy of the tube can be improved by using induction heating and quenching to reduce the amount of time it is exposed to high temperatures.
It is well maintained, and manufacturing efficiency can be extremely high by avoiding the conventional multi-layer welding with a small heat input and using single-layer welding on both sides with a large heat input.
第１図は本発明法実施例における焼入れ時の加
熱、冷却の温度パターンを示した線図、第２図は
同じく焼戻し時の加熱、冷却の温度パターンを示
した線図である。
FIG. 1 is a diagram showing the temperature pattern of heating and cooling during quenching in an embodiment of the method of the present invention, and FIG. 2 is a diagram showing the temperature pattern of heating and cooling during tempering.
Claims (1)
鋼板を管状に成形し、該管状体のシーム部を内外
面から各々一層盛り溶接して直径16インチ以上の
鋼管となし、該鋼管を誘導加熱によりA3点以上
の温度に加熱後焼入れ（水焼入れ）処理し、次い
でA1点以下の温度で焼戻すことを特徴とする3.5
％Ni大径鋼管の製造方法。1 3.5% Ni with plate thickness of 5 mm to 25.4 mm as hot rolled
A steel plate is formed into a tubular shape, and the seam part of the tubular body is welded in one layer from the inner and outer surfaces to make a steel pipe with a diameter of 16 inches or more.The steel pipe is heated by induction heating to a temperature of A 3 or more, and then quenched (water-treated). 3.5 characterized by quenching) treatment and then tempering at a temperature below A1 point
%Ni large diameter steel pipe manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13987379A JPS5665925A (en) | 1979-10-31 | 1979-10-31 | Manufacture of large diameter steel pipe containing 3.5% ni |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13987379A JPS5665925A (en) | 1979-10-31 | 1979-10-31 | Manufacture of large diameter steel pipe containing 3.5% ni |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5665925A JPS5665925A (en) | 1981-06-04 |
| JPS6317890B2 true JPS6317890B2 (en) | 1988-04-15 |
Family
ID=15255542
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13987379A Granted JPS5665925A (en) | 1979-10-31 | 1979-10-31 | Manufacture of large diameter steel pipe containing 3.5% ni |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5665925A (en) |
-
1979
- 1979-10-31 JP JP13987379A patent/JPS5665925A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5665925A (en) | 1981-06-04 |
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