JPS61207515A - Cooling method for metallic pipe - Google Patents

Abstract

PURPOSE:To cool a metallic pipe material having large hardenability quickly and efficiently without generating quench cracks in the stage of cooling said pipe material by cooling first the metallic pipe with mists then cooling the pipe with gaseous jets. CONSTITUTION:The pipe material A of a high temp. produced by the metal such as high C-Cr-Mo steel having the large hardenability is cooled while the material is conveyed by rollers 18. The pipe material is first conveyed to a mist cooler 11 where the material is cooled by the liquid drop-like small mists sprayed from mist nozzles 14 by air headers 12 and water headers 13 toward the periphery of the pipe A down to about 350 deg.C. The pipe is then fed into a gaseous jet cooler 15, where the pipe is cooled by the gaseous jets blown from slit nozzles 16 connected to air headers 17. The metallic pipe having the large hardenability is thus cooled by such two-stage cooling without generating quench cracks.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 この発明は、金属管、特に焼入性が大きくて外面水スプ
レー冷却では焼割れを生じる金属管を迅速に且つ焼割れ
を生じさせずに冷却する方法に関するものである。[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for quickly and without causing quench cracks in metal pipes, particularly metal pipes that have high hardenability and which would cause quench cracks when the outer surface is cooled with water spray. The present invention relates to a cooling method.

〔従来技術とその問題点〕[Prior art and its problems]

油井用部品等に広く、高ＣＣｒ−Ｍｏ鋼等メカニカルチ
ューブが使用されているが、この種管材は炭素含有量が
０．３％以上であって焼入性が大きく、第５図に示すよ
うな外面水スプレ一方式では、焼割れを生じる。なお、
第５図中、Ａは金属管、１は金属管Ａを周方向に自転さ
せつつ軸方向に１般送するスキューローラ、２は水ヘツ
ダ、３は水噴射ノズルを示す。Mechanical tubes such as high CCr-Mo steel are widely used in oil well parts, etc., but this type of tube material has a carbon content of 0.3% or more and is highly hardenable, as shown in Figure 5. One type of external water spray will cause quenching cracks. In addition,
In FIG. 5, A is a metal tube, 1 is a skew roller that rotates the metal tube A in the circumferential direction and generally feeds it once in the axial direction, 2 is a water header, and 3 is a water injection nozzle.

すなわち、水スプレーで低温域の緩冷却を行おうとして
も、水スプレーは冷却能が鋭敏で水量コントロールの巾
が極めて狭く、従って作業性が悪く且つ安定した冷却を
行い得ない。That is, even if an attempt is made to perform slow cooling in a low temperature range using a water spray, the cooling ability of the water spray is sensitive and the range of water amount control is extremely narrow, resulting in poor workability and inability to perform stable cooling.

そこで従来、上記焼入性の大きな金属管については油浸
漬冷却が採用されているが、浸漬冷却は金属管Ａをパス
ライン上で一旦停止させることとなり生産性が悪く、設
備が大がかりとなり、操作が複雑なこと、更には廃油処
理が必要とされ、この結果製造コストが非常に高くなる
という問題がある。Therefore, conventionally, oil immersion cooling has been adopted for metal tubes with high hardenability, but immersion cooling requires metal tube A to be temporarily stopped on the pass line, resulting in poor productivity, large-scale equipment, and operation. However, there are problems in that the process is complicated and waste oil treatment is required, resulting in very high production costs.

〔発明の目的〕[Purpose of the invention]

本発明は、上記実情に鑑み、焼入性の大きな金属管に対
しても、焼割れを起させることなく簡便に、且つ効率よ
く、ライン−ヒで迅速に冷却し得る金属管の冷却方法を
提案する目的でなされたものである。In view of the above-mentioned circumstances, the present invention provides a method for cooling metal tubes that can be simply and efficiently cooled quickly in a line without causing quench cracking, even for metal tubes with high hardenability. This was done for the purpose of making a proposal.

〔発明の構成〕[Structure of the invention]

上記目的を達成するために本発明は次のような技術手段
を採用する。In order to achieve the above object, the present invention employs the following technical means.

すなわち、高温状態にある金属管を軸方向に搬送しつつ
冷却するに際し、高温部をミスト冷却に委ね、その後を
ガスジェット冷却に委ねる２段冷却とすることを、その
特徴とする。That is, when a metal tube in a high temperature state is cooled while being conveyed in the axial direction, a two-stage cooling is performed in which the high temperature part is entrusted to mist cooling and the subsequent part is entrusted to gas jet cooling.

ここで、「高温状態にある」とは、「オーステナイト組
織となっていること」を意味し、「高温部」とは「ベイ
ナイト変態の完了前」を意味する。Here, "being in a high temperature state" means "being in an austenite structure", and "high temperature section" means "before completion of bainite transformation".

従ってベイナイト変態の完了時点までは、金属管はミス
ト冷却に委ねられ、その後はガスジェット冷却に委ねら
れる。Therefore, the metal tube is subjected to mist cooling until the completion of the bainitic transformation, and thereafter to gas jet cooling.

また、ミスト冷却を採用した理由は、■水スプレー冷却
に比して液滴径が小さく且つ粒径゛が揃っているため均
一緩冷却に優れ良好なベイナイト変態が期待できる、■
水量が水スプレー冷却に比して少なく低温部（ベイナイ
ト変態終了後の）冷却装置への水付着が生じない、とい
う利点があるためである。In addition, the reasons why mist cooling was adopted are: 1) Compared to water spray cooling, the droplet size is smaller and the particle size is more uniform, so it excels in uniform slow cooling, and good bainite transformation can be expected.
This is because the amount of water is small compared to water spray cooling, and there is an advantage that water does not adhere to the cooling device at the low temperature section (after the completion of bainite transformation).

更にまた、ヘイナイト変態終了後（２００℃〜３５０℃
）の冷却にガスジェット冷却を用いた理由は、油浸漬冷
却の温度曲線並びにこれに関与する冷却能を検討した結
果、低温部の熱伝達率を３００　Ｋｃａｌ　／　ｒｄｈ
　’Ｃ程度にする必要があり、核部の冷却をミスト冷却
に委ねた場合には、金属管の周方向にアンバランスを生
しることを知見するに至ったからである。Furthermore, after completion of haynite transformation (200℃~350℃
) The reason for using gas jet cooling for cooling is that after studying the temperature curve of oil immersion cooling and the cooling capacity involved, we determined that the heat transfer coefficient in the low temperature section was 300 Kcal/rdh.
This is because it has been found that if the cooling of the core is entrusted to mist cooling, an imbalance will occur in the circumferential direction of the metal tube.

〔作用〕[Effect]

本発明は、例えば第１〜２図に略示する如き装置を用い
て実施する。The invention may be practiced, for example, using an apparatus such as that schematically shown in FIGS. 1-2.

すなわち、第１図は装置の一例を示す縦断面図、第２図
は第１図におけるｎ−ｎ断面図、第３図は同ｍ−ｍ断面
図で、金属管Ａの高温部を冷却するミスト冷却装置ｆｌ
ｌは、水ヘツダ１３、空気ヘッダ１２、これ等両ヘッダ
１３．１２から水及び空気が供給され金属管Ａ外周にミ
ストを噴射するミストノズル１４を備えている。また、
１５は」−記ミスト冷却装置１１の下流側に配されたガ
スジェット冷却装置で、金属管Ａの低温部を冷却する役
割を担い、金属管Ａ外周に臨む多数本のスリットノズル
１６及び該スリットノズル１６にガスジェットを供給す
る例えば空気ヘッダ１７を備えている。その他１８は金
属管Ａを回転（自転）させつつ軸方向に搬送するスキュ
ーローラである。That is, FIG. 1 is a longitudinal cross-sectional view showing an example of the apparatus, FIG. 2 is a cross-sectional view taken along the line nn in FIG. 1, and FIG. 3 is a cross-sectional view taken along the mm line in FIG. Mist cooling device fl
1 is equipped with a water header 13, an air header 12, and a mist nozzle 14 to which water and air are supplied from both headers 13 and 12, and which sprays mist onto the outer periphery of the metal tube A. Also,
15 is a gas jet cooling device arranged downstream of the mist cooling device 11, which plays the role of cooling the low temperature part of the metal tube A, and has a large number of slit nozzles 16 facing the outer periphery of the metal tube A and the slits. For example, an air header 17 is provided to supply the nozzle 16 with a gas jet. Others 18 are skew rollers that transport the metal tube A in the axial direction while rotating (rotating) it.

まず、高温状態にある金属管、Ａは、スキューローラ１
８でミスト冷却装置１１に搬送され、約３５０℃にまで
冷却されるのであり、ここで金属管Ａ、は液滴径の小さ
なミストにより均一な緩冷却を受けて、オーステナイト
組織からベイナイト組織へと変態を起し、該変態は、ガ
スジェット冷却袋Ｗ１５に至るまでに終了することにな
る。すなわち、第４図における破線ａよりも上の温度変
化部分がこれを示す。First, the metal tube A in a high temperature state is the skew roller 1
At step 8, the metal tube A is transported to the mist cooling device 11 and cooled to about 350°C, where the metal tube A is uniformly and slowly cooled by the mist with small droplet diameters, changing from an austenite structure to a bainite structure. A transformation occurs, and the transformation ends before reaching the gas jet cooling bag W15. That is, the temperature change portion above the broken line a in FIG. 4 shows this.

次に、金属管Ａは、第４図に示す如く、更に緩やかな緩
冷却に委ねられる必要があり、本発明はこれをガスジェ
ット冷却に委ねている。すなわち、ガスジェット冷却は
、上述のミスト冷却よりも熱伝達率が低く、緩やかな冷
却曲線が得られるからである。Next, as shown in FIG. 4, the metal tube A needs to be subjected to even more gradual cooling, and the present invention entrusts this to gas jet cooling. That is, gas jet cooling has a lower heat transfer coefficient than the above-mentioned mist cooling, and a gentler cooling curve can be obtained.

換言すれば、本発明は、油浸漬冷却と略々同一の冷却曲
線を得られる冷却方法であって、第４図に示す実線は油
浸漬冷却の冷却曲線を、黒丸（ドツト）は本発明の冷却
温度変化（後述の実施例によるもの）をプロットしたも
のである。In other words, the present invention is a cooling method that can obtain a cooling curve that is almost the same as that of oil immersion cooling, and the solid line shown in FIG. It is a plot of cooling temperature change (according to an example described later).

〔実施例〕〔Example〕

以下、実施例について説明する。 Examples will be described below.

Ｃ：０．３９％、Ｓｉ：０．２７％、Ｍｎ：０゜８８％
、Ｃｒ：０．９７％、Ｍｏ：０．２１％を含有する外径
：５３，５ｍｍ、肉厚：９．６７ｍｍの高ＣＣｒ　　Ｍ
ｏ綱管を９００℃に加熱後、ミスト冷却装置１１　（平
均水量密度４００　（１／　ｍｍ１ｎ）に３０ｓｅｃ通
過させ、しかる後、ガスジェット冷却袋Ｗ１５（ガス温
度３０℃、ガス噴出速度５０ｍ／５ｅｃ）に７０ｓｅｃ
間通過せしめて外面焼入れ（冷却）を施した結果、第４
図に示すように肉厚中央部の温度推移は油浸消冷却と同
様のパターンとなり、６００℃のテンパー後の機械的性
質も、下記表に示す如く良好なものであった。勿論、本
発明冷却方法では、油浸漬冷却同様に焼割れは生じなか
った。C: 0.39%, Si: 0.27%, Mn: 0°88%
, high CCr M with outer diameter: 53.5 mm and wall thickness: 9.67 mm, containing Cr: 0.97%, Mo: 0.21%
After heating the o-wire pipe to 900°C, it is passed through a mist cooling device 11 (average water flow density 400 (1/mm1n) for 30 seconds, and then passed through a gas jet cooling bag W15 (gas temperature 30°C, gas ejection speed 50m/5ec). 70 seconds
As a result of hardening (cooling) the outer surface of the
As shown in the figure, the temperature transition at the center of the wall thickness had a pattern similar to that of oil immersion cooling, and the mechanical properties after tempering at 600°C were also good as shown in the table below. Of course, in the cooling method of the present invention, no quenching cracks occurred, as in oil immersion cooling.

表：機械的性質 〔効果〕 以上説明したように本発明冷却方法は、高温部をミスト
冷却、低温部をガスジェット冷却するという２段冷却方
式を採用したものであり、油浸消冷却と同様の冷却パタ
ーン、ずなわち、焼割れの生じない冷却パターン示温ら
れ、水及びガスを用いるためハンドリングが容易で設備
も簡素になり、安価に実施できるという効益著しい発明
である。Table: Mechanical properties [Effects] As explained above, the cooling method of the present invention employs a two-stage cooling method in which high-temperature parts are cooled with mist and low-temperature parts are cooled with gas jet, and is similar to oil immersion cooling. This invention has a remarkable effect in that it has a cooling pattern that does not cause quenching cracks, is easy to handle, has simple equipment, and can be implemented at low cost because it uses water and gas.

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

第１図は本発明の実施に用いる装置例の縦断面図、第２
図は第１図におけるｎ−ｎ断面図、第３図は同ｍ−ｍ断
面図、第４図は本発明方法の冷却パターンを油浸漬冷却
パターンに比較して示すグラフ、第５図は従来の水スプ
レー冷却装置の断面図である。 Ａは金属管、１１はミスト冷却装置、１５はガスジェッ
ト冷却装置、１８はスキューローラ。 特許出願人　住友金属工業株式会社 第１図 メ１ 第２図　　　　　　第３図 第４図FIG. 1 is a vertical cross-sectional view of an example of an apparatus used for carrying out the present invention, and FIG.
The figure is a sectional view taken along the line nn in Figure 1, Figure 3 is a cross-sectional view taken along the line mm, Figure 4 is a graph comparing the cooling pattern of the method of the present invention with the oil immersion cooling pattern, and Figure 5 is the conventional method. 1 is a cross-sectional view of a water spray cooling device of FIG. A is a metal tube, 11 is a mist cooling device, 15 is a gas jet cooling device, and 18 is a skew roller. Patent applicant: Sumitomo Metal Industries, Ltd. Figure 1 Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

【特許請求の範囲】[Claims] 高温状態にある金属管を軸方向に搬送しつつ冷却するに
際し、高温部をミスト冷却に委ね、その後をガスジェッ
ト冷却に委ねる２段冷却とすることを特徴とする金属管
の冷却方法。A method for cooling a metal tube, which is characterized in that when a metal tube in a high temperature state is cooled while being conveyed in the axial direction, a two-stage cooling is performed in which the high temperature part is entrusted to mist cooling and the subsequent part is entrusted to gas jet cooling.