JP2022509978A - Chromium molybdenum steel sheet with excellent creep strength and its manufacturing method - Google Patents

Chromium molybdenum steel sheet with excellent creep strength and its manufacturing method Download PDF

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JP2022509978A
JP2022509978A JP2021530277A JP2021530277A JP2022509978A JP 2022509978 A JP2022509978 A JP 2022509978A JP 2021530277 A JP2021530277 A JP 2021530277A JP 2021530277 A JP2021530277 A JP 2021530277A JP 2022509978 A JP2022509978 A JP 2022509978A
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steel sheet
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ソン，ヒョン－ジェ
キム，デ－ウ
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Posco Holdings Inc
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Abstract

【課題】クリープ強度に優れたクロムモリブデン鋼板及びその製造方法を提供する。【解決手段】本発明のクリープ強度に優れたクロムモリブデン鋼板は、重量％で、Ｃ：０．１１～０．１５％、Ｓｉ：０．１０％以下（０％は除く）、Ｍｎ：０．３～０．６％、Ｓ：０．０１０％以下（０％は除く）、Ｐ：０．０１５％以下（０％は除く）、Ｃｒ：２．０～２．５％、Ｍｏ：０．９～１．１％、Ｖ：０．６５～１．０％、Ｎｉ：０．２５％以下（０％は除く）、Ｃｕ：０．２０％以下（０％は除く）、Ｎｂ：０．０７％以下（０％は除く）、Ｔｉ：０．０３％以下（０％は除く）、Ｎ：０．０１５％以下（０％は除く）、Ａｌ：０．０２５％以下（０％は除く）、Ｂ：０．００２％以下（０％は除く）、残部はＦｅ及び不可避不純物からなる。【選択図】図１PROBLEM TO BE SOLVED: To provide a chrome molybdenum steel sheet having excellent creep strength and a method for producing the same. SOLUTION: The chromium molybdenum steel plate having excellent creep strength of the present invention has C: 0.11 to 0.15%, Si: 0.10% or less (excluding 0%), Mn: 0. 3 to 0.6%, S: 0.010% or less (excluding 0%), P: 0.015% or less (excluding 0%), Cr: 2.0 to 2.5%, Mo: 0. 9 to 1.1%, V: 0.65 to 1.0%, Ni: 0.25% or less (excluding 0%), Cu: 0.20% or less (excluding 0%), Nb: 0. 07% or less (excluding 0%), Ti: 0.03% or less (excluding 0%), N: 0.015% or less (excluding 0%), Al: 0.025% or less (excluding 0%) ), B: 0.002% or less (excluding 0%), the balance consists of Fe and unavoidable impurities. [Selection diagram] Fig. 1

Description

本発明は、クリープ特性に優れたクロムモリブデン鋼板の製造に関し、より詳細には、鋼材の構成相であるマルテンサイト基地の内部と結晶粒界に微細な炭窒化物のみを形成させることで、高温での転位移動を妨げ、亜結晶粒の安定性を確保することにより、優れたクリープ強度を有することができるクロムモリブデン鋼板、及びその製造方法に関する。 The present invention relates to the production of a chrome molybdenum steel plate having excellent creep characteristics. More specifically, the present invention forms only fine carbonitoxide inside a martensite matrix which is a constituent phase of a steel material and at grain boundaries, thereby forming a high temperature. The present invention relates to a chromoly molybdenum steel sheet capable of having excellent creep strength by hindering dislocation movement in the sea and ensuring the stability of subcrystal grains, and a method for producing the same.

発電及び精油／精製産業において考慮すべき事項は、環境にやさしい設備の建設とエネルギー利用の高効率化である。 A consideration in the power generation and refinery / refining industry is the construction of environmentally friendly equipment and the efficient use of energy.

先ず、発電効率を上げるためには、タービンに供給される蒸気の温度及び圧力の増加が必要であるが、そのためには、より高い温度で蒸気を生産することができるボイラー素材の耐熱性を向上させることが不可欠である。 First, in order to increase the power generation efficiency, it is necessary to increase the temperature and pressure of the steam supplied to the turbine, and for that purpose, improve the heat resistance of the boiler material that can produce steam at a higher temperature. It is essential to let them do it.

また、精油／精製産業においても、近年、環境規制の強化に伴い、高効率化のために増加した温度及び圧力において優れた特性を有する鋼材が開発されている。 Further, in the essential oil / refining industry as well, in recent years, with the tightening of environmental regulations, steel materials having excellent properties at an increased temperature and pressure for high efficiency have been developed.

オーステナイトステンレス鋼は、高価の合金元素を多量含有しているため価格が高く、低い熱伝導度と高い熱膨張係数の物理的性質を有し、大型部品の製造が困難であるため、その使用が制限的である。これに対し、クロム鋼は、優れたクリープ強度、溶接性、耐腐食性、及び耐酸化性などにより、多用されている。 Austenite stainless steel is expensive because it contains a large amount of expensive alloying elements, has low thermal conductivity and high thermal expansion coefficient physical properties, and is difficult to manufacture large parts, so its use is difficult. It is restrictive. On the other hand, chrome steel is widely used due to its excellent creep strength, weldability, corrosion resistance, oxidation resistance, and the like.

耐熱クロム鋼の高温クリープ強度を長時間維持させるために、固溶強化及び析出強化方法が適用されている。そのために、モリブデン、及びＭ（Ｃ，Ｎ）炭窒化物（Ｍ＝金属原素、Ｃ＝炭素、Ｎ＝窒素）の形成元素であるバナジウム、ニオブ、チタンが主に合金される。同時に、炭素の含量を０．００２重量％に極端に減少させることにより、熱力学的に不安定で、かつ粗大化しやすくてクリープ特性を低下させる（Ｆｅ，Ｃｒ）２３Ｃ６炭化物の形成を抑え、微細な炭窒化物を析出させてクリープ特性を大きく向上させた耐熱鋼も提案されている。しかし、炭素の含量を減少させた耐熱鋼を商業的に大量生産することはほとんど不可能な状況である。 In order to maintain the high temperature creep strength of heat resistant chromium steel for a long time, solid solution strengthening and precipitation strengthening methods are applied. Therefore, molybdenum and vanadium, niobium, and titanium, which are the forming elements of M (C, N) carbonitride (M = metal element, C = carbon, N = nitrogen), are mainly alloyed. At the same time, by drastically reducing the carbon content to 0.002% by weight, the formation of 23 C6 carbides, which are thermodynamically unstable and easily coarsened and deteriorate the creep characteristics (Fe, Cr), is suppressed. Also proposed are heat-resistant steels in which fine carbonitrides are deposited to greatly improve creep characteristics. However, it is almost impossible to mass-produce heat-resistant steel with a reduced carbon content commercially.

本発明は、合金設計及び熱処理を用いて、前述の従来技術とは異なって、炭素の含量を極端に減少させなくても（Ｆｅ，Ｃｒ）２３Ｃ６炭化物のような粗大析出物の形成を完全に抑え、微細な炭窒化物のみを形成させることで、優れたクリープ特性を有するクロムモリブデン鋼板及びその製造方法を提供することを目的とする。 The present invention uses alloy design and heat treatment to form coarse precipitates such as (Fe, Cr) 23 C6 carbides without significantly reducing the carbon content, unlike the prior art described above. It is an object of the present invention to provide a chromium molybdenum steel plate having excellent creep characteristics and a method for producing the same, by completely suppressing the formation and forming only fine carbides.

本発明によるクリープ強度に優れたクロムモリブデン鋼板は、重量％で、Ｃ：０．１１～０．１５％、Ｓｉ：０．１０％以下（０％は除く）、Ｍｎ：０．３～０．６％、Ｓ：０．０１０％以下（０％は除く）、Ｐ：０．０１５％以下（０％は除く）、Ｃｒ：２．０～２．５％、Ｍｏ：０．９～１．１％、Ｖ：０．６５～１．０％、Ｎｉ：０．２５％以下（０％は除く）、Ｃｕ：０．２０％以下（０％は除く）、Ｎｂ：０．０７％以下（０％は除く）、Ｔｉ：０．０３％以下（０％は除く）、Ｎ：０．０１５％以下（０％は除く）、Ａｌ：０．０２５％以下（０％は除く）、Ｂ：０．００２％以下（０％は除く）、残部はＦｅ及び不可避不純物からなることを特徴とする。 The chromium molybdenum steel plate having excellent creep strength according to the present invention has C: 0.11 to 0.15%, Si: 0.10% or less (excluding 0%), Mn: 0.3 to 0. 6%, S: 0.010% or less (excluding 0%), P: 0.015% or less (excluding 0%), Cr: 2.0 to 2.5%, Mo: 0.9 to 1. 1%, V: 0.65 to 1.0%, Ni: 0.25% or less (excluding 0%), Cu: 0.20% or less (excluding 0%), Nb: 0.07% or less (excluding 0%) 0% or less), Ti: 0.03% or less (excluding 0%), N: 0.015% or less (excluding 0%), Al: 0.025% or less (excluding 0%), B: It is characterized in that it is 0.002% or less (excluding 0%), and the balance is composed of Fe and unavoidable impurities.

前記鋼板は、焼戻しマルテンサイト（ｔｅｍｐｅｒｅｄ ｍａｒｔｅｎｓｉｔｅ）を含む微細組織を有することを特徴とする。 The steel sheet is characterized by having a microstructure containing tempered martensite.

前記鋼板の微細組織には、（Ｆｅ，Ｃｒ）２３Ｃ６を含む直径２００ｎｍ以上の析出物が１個／μｍ２以下の個数範囲で存在することを特徴とする。 The fine structure of the steel sheet is characterized in that precipitates containing (Fe, Cr) 23 C 6 and having a diameter of 200 nm or more are present in a number range of 1 piece / μm 2 or less.

前記鋼板の微細組織には、直径２０ｎｍ以下の析出物が２０個／μｍ２以上の個数範囲で存在することを特徴とする。 The fine structure of the steel sheet is characterized in that precipitates having a diameter of 20 nm or less are present in a number range of 20 pieces / μm 2 or more.

前記直径２０ｎｍ以下の析出物は、（Ｖ，Ｍｏ，Ｎｂ，Ｔｉ）（Ｃ，Ｎ）であることを特徴とする。 The precipitate having a diameter of 20 nm or less is characterized by being (V, Mo, Nb, Ti) (C, N).

本発明によるクリープ強度に優れたクロムモリブデン鋼板の製造方法は、上述の組成の鋼スラブを仕上圧延温度がＡｒ３以上になるように熱間圧延して熱延鋼板を製造した後、冷却する工程と、前記冷却された熱延鋼板を、９００～１２００℃の温度範囲で１ｔ～３ｔ分［ｔ（ｍｍ）は、熱延鋼板の厚さである］間再加熱してオーステナイト化する工程と、前記オーステナイト化された熱延鋼板を常温に焼入れする工程と、前記焼入された熱延鋼板を、６７５～８００℃の温度範囲で３０分～１２０分間焼戻し（ｔｅｍｐｅｒｉｎｇ）する工程と、を含んでなることを特徴とする。 The method for producing a chrome molybdenum steel sheet having excellent creep strength according to the present invention includes a step of hot rolling a steel slab having the above composition so that the finish rolling temperature becomes Ar3 or higher to produce a hot-rolled steel sheet, and then cooling the steel slab. The step of reheating the cooled hot-rolled steel sheet in a temperature range of 900 to 1200 ° C. for 1 to 3 tons [t (mm) is the thickness of the hot-rolled steel sheet] to austenite, and the above-mentioned step. It comprises a step of quenching the austenized hot-rolled steel sheet to room temperature and a step of tempering the hardened hot-rolled steel sheet in a temperature range of 675 to 800 ° C. for 30 minutes to 120 minutes. It is characterized by that.

本発明のクリープ特性に優れたクロムモリブデン鋼板によれば、焼入れと焼戻しによる高温での優れたクリープ寿命により、９重量％の多量のクロムを含有するＡＳＴＭ Ａ３８７ Ｇｒａｄｅ ９１鋼よりも長いクリープ寿命を有することができる。 According to the chrome molybdenum steel sheet having excellent creep properties of the present invention, the creep life is longer than that of the ASTM A387 Grade 91 steel containing a large amount of 9% by weight of chromium due to the excellent creep life at high temperature by quenching and tempering. be able to.

本発明の実験に用いられた鋼種１－４と従来材に対するクリープ試験結果を比較して示した図である。It is a figure which compared and showed the creep test result with respect to the steel type 1-4 used in the experiment of this invention, and the conventional material. 本発明の実験に用いられた鋼種１において、オーステナイト化後における冷却速度による相変態を示す、ディラトメーター（Ｄｉｌａｔｏｍｅｔｅｒ）試験結果を示したグラフである。It is a graph which showed the phase transformation by the cooling rate after austenitization in the steel type 1 used for the experiment of this invention, and showed the dilatometer test result. 本発明の実験に用いられた鋼種 ２ において、オーステナイト化後における冷却速度による相変態を示す、ディラトメーター（Ｄｉｌａｔｏｍｅｔｅｒ）試験結果を示したグラフである。It is a graph which showed the phase transformation by the cooling rate after austenitization in the steel type 2 used for the experiment of this invention, and showed the dilatometer test result. 本発明の実験に用いられた鋼種 ３ において、オーステナイト化後における冷却速度による相変態を示す、ディラトメーター（Ｄｉｌａｔｏｍｅｔｅｒ）試験結果を示したグラフである。It is a graph which showed the phase transformation by the cooling rate after austenitization in the steel type 3 used for the experiment of this invention, and showed the dilatometer test result. 本発明の実験に用いられた鋼種 ４ において、オーステナイト化後における冷却速度による相変態を示す、ディラトメーター（Ｄｉｌａｔｏｍｅｔｅｒ）試験結果を示したグラフである。It is a graph which showed the phase transformation by the cooling rate after austenitization in the steel type 4 used in the experiment of this invention, and showed the dilatometer test result. クロムモリブデン鋼板中のバナジウムの含量による、（Ｆｅ，Ｃｒ）２３Ｃ６炭化物形成のギブス自由エネルギーの変化を示したグラフである。It is a graph which showed the change of the Gibbs free energy of (Fe, Cr) 23 C6 carbide formation by the content of vanadium in a chromium molybdenum steel sheet. 本発明の実験に用いられた鋼種１－４に対する走査型電子顕微鏡（ｓｃａｎｎｉｎｇ ｅｌｅｃｔｒｏｎ ｍｉｃｒｏｓｃｏｐｅ、ＳＥＭ）写真である。It is a scanning electron microscope (SEM) photograph for steel type 1-4 used in the experiment of this invention.

以下、本発明の実施例を、図面を参照して詳しく説明する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

前述のように、従来の耐熱クロム鋼は、合金成分として、モリブデン、及びＭ（Ｃ，Ｎ）炭窒化物（Ｍ＝金属原素、Ｃ＝炭素、Ｎ＝窒素）の形成元素であるバナジウム、ニオブ、チタンが主に用いられていたが、このような耐熱クロム鋼は、熱力学的に不安定であり、粗大化しやすいため、クリープ特性を低下させる（Ｆｅ，Ｃｒ）２３Ｃ６炭化物の形成を避けることができず、優れたクリープ特性を確保することが困難であった。 As described above, the conventional heat-resistant chromium steel has molybdenum as an alloy component and vanadium, which is a forming element of M (C, N) carbonitoxide (M = metal element, C = carbon, N = nitrogen). Although niobium and titanium were mainly used, such heat - resistant chromium steel is thermodynamically unstable and tends to be coarsened, so that the creep property is deteriorated (Fe, Cr) formation of 23 C6 carbides. It was difficult to secure excellent creep characteristics.

このような従来技術の問題を解消するための実験を重ねた結果、２．０～２．５％のＣｒを含有する耐熱クロム鋼の合金におけるバナジウムの添加量を最適化するとともに、焼戻しの温度を適宜制御することで、優れたクリープ特性を有する耐熱クロム鋼が得られることを確認した。 As a result of repeated experiments to solve such problems of the prior art, the amount of vanadium added to the alloy of heat-resistant chromium steel containing 2.0 to 2.5% Cr was optimized, and the tempering temperature was improved. It was confirmed that a heat-resistant chromium steel having excellent creep characteristics can be obtained by appropriately controlling the above.

本発明のクリープ強度に優れたクロムモリブデン鋼板は、重量％で、Ｃ：０．１１～０．１５％、Ｓｉ：０．１０％以下（０％は除く）、Ｍｎ：０．３～０．６％、Ｓ：０．０１０％以下（０％は除く）、Ｐ：０．０１５％以下（０％は除く）、Ｃｒ：２．０～２．５％、Ｍｏ：０．９～１．１％、Ｖ：０．６５～１．０％、Ｎｉ：０．２５％以下（０％は除く）、Ｃｕ：０．２０％以下（０％は除く）、Ｎｂ：０．０７％以下（０％は除く）、Ｔｉ：０．０３％以下（０％は除く）、Ｎ：０．０１５％以下（０％は除く）、Ａｌ：０．０２５％以下（０％は除く）、Ｂ：０．００２％以下（０％は除く）、残部はＦｅ及び不可避不純物からなる。 The chromium molybdenum steel plate having excellent creep strength of the present invention has C: 0.11 to 0.15%, Si: 0.10% or less (excluding 0%), Mn: 0.3 to 0% in weight%. 6%, S: 0.010% or less (excluding 0%), P: 0.015% or less (excluding 0%), Cr: 2.0 to 2.5%, Mo: 0.9 to 1. 1%, V: 0.65 to 1.0%, Ni: 0.25% or less (excluding 0%), Cu: 0.20% or less (excluding 0%), Nb: 0.07% or less (excluding 0%) 0% or less), Ti: 0.03% or less (excluding 0%), N: 0.015% or less (excluding 0%), Al: 0.025% or less (excluding 0%), B: 0.002% or less (excluding 0%), the balance consists of Fe and unavoidable impurities.

以下、クリープ特性に優れたクロムモリブデン鋼板の成分を限定する理由を説明する。ここで、「％」は「重量％」である。 Hereinafter, the reason for limiting the components of the chromium molybdenum steel sheet having excellent creep characteristics will be described. Here, "%" is "weight%".

炭素（Ｃ）：０．１１～０．１５％
炭素はオーステナイト安定化元素であり、その含量によって、Ａｅ３温度とマルテンサイト形成開始温度を調節可能な元素である。また、侵入型元素であって、マルテンサイト相の格子構造に非対称的な歪みを加え、強力な強度の確保に非常に効果的な元素である。しかし、鋼中の炭素の含量が０．１５％を超える場合には、炭化物が過度に形成され、溶接性が著しく低下するという欠点がある。 Carbon (C): 0.11 to 0.15%
Carbon is an austenite stabilizing element, and its content can regulate the Ae3 temperature and the martensite formation start temperature. In addition, it is an intrusive element that adds asymmetric strain to the lattice structure of the martensite phase and is extremely effective in ensuring strong strength. However, when the carbon content in the steel exceeds 0.15%, there is a drawback that carbides are excessively formed and the weldability is significantly deteriorated.

したがって、本発明では、炭素の含量を０．１１～０．１５％の範囲に制限することが好ましく、より好ましくは０．１１～０．１４％の範囲に制限する。 Therefore, in the present invention, the carbon content is preferably limited to the range of 0.11 to 0.15%, more preferably to the range of 0.11 to 0.14%.

シリコン（Ｓｉ）：０．１０％以下（０％を除く）
シリコンは、固溶強化だけでなく、鋳造時に脱酸剤として添加される。但し、本発明の一実施形態によるクリープ特性に優れたクロムモリブデン鋼板は、微細な炭化物のような有益な炭化物の形成が必須であるが、シリコンは炭化物の形成を抑制する役割をする。 Silicon (Si): 0.10% or less (excluding 0%)
Silicon is added as a deoxidizer during casting as well as solid solution strengthening. However, the chromium molybdenum steel sheet having excellent creep characteristics according to one embodiment of the present invention is indispensable for the formation of beneficial carbides such as fine carbides, but silicon plays a role of suppressing the formation of carbides.

したがって、本発明では、シリコンの含量を０．１０％以下に制限することが好ましく、より好ましくは０．００５～０．０８％の範囲に制限する。 Therefore, in the present invention, the silicon content is preferably limited to 0.10% or less, more preferably 0.005 to 0.08%.

マンガン（Ｍｎ）：０．３～０．６％
マンガンはオーステナイト安定化元素であり、鋼の硬化能を大きく増加させ、マルテンサイトのような硬質相が形成されるようにする。また、硫黄と反応してＭｎＳを析出させるが、これは、硫黄の偏析による高温割れを防止するのに有利である。これに対し、マンガンの含量が増加するほど、オーステナイト安定度が過度に増加するという問題がある。 Manganese (Mn): 0.3-0.6%
Manganese is an austenite stabilizing element that greatly increases the hardening capacity of steel and allows the formation of hard phases such as martensite. It also reacts with sulfur to precipitate MnS, which is advantageous in preventing high temperature cracking due to segregation of sulfur. On the other hand, there is a problem that the austenite stability is excessively increased as the manganese content is increased.

したがって、本発明では、マンガンの含量を０．３～０．６％の範囲に制限することが好ましく、より好ましくは０．３５～０．５５％の範囲に制限する。 Therefore, in the present invention, the manganese content is preferably limited to the range of 0.3 to 0.6%, more preferably to the range of 0.35 to 0.55%.

硫黄（Ｓ）：０．０１０％以下（０％は除く）
硫黄は不純物元素であり、その含量が０．０１０％を超える場合には、鋼の軟性と溶接性が低下する。 Sulfur (S): 0.010% or less (excluding 0%)
Sulfur is an impurity element, and when its content exceeds 0.010%, the softness and weldability of steel are reduced.

したがって、硫黄の含量を０．０１０％以下に制限することが好ましい。 Therefore, it is preferable to limit the sulfur content to 0.010% or less.

リン（Ｐ）：０．０１５％以下（０％を除く）
リンは、固溶強化の効果を奏する元素であるが、硫黄と同様に不純物元素である。その含量が０．０１５％を超える場合には、鋼に脆性が発生し、溶接性が低下する。 Phosphorus (P): 0.015% or less (excluding 0%)
Phosphorus is an element that has the effect of strengthening solid solution, but it is an impurity element like sulfur. If the content exceeds 0.015%, brittleness occurs in the steel and weldability is deteriorated.

したがって、リンの含量を０．０１５％以下に制限することが好ましい。 Therefore, it is preferable to limit the phosphorus content to 0.015% or less.

クロム（Ｃｒ）：２．０～２．５％
クロムはフェライト安定化元素であり、硬化能を増加させる元素であって、その量によって、Ａｅ３温度及びデルタフェライト形成領域温度を調節する。また、クロムは酸素と反応し、Ｃｒ２Ｏ３の緻密かつ安定な保護被膜を形成して、高温耐酸化性及び耐腐食性を増大させるが、デルタフェライト形成温度領域を広げる。高いクロム含量を有する鋼の鋳造過程でデルタフェライトが形成される可能性があり、熱処理後にも残留して鋼材の特性に悪影響を与える。 Chromium (Cr): 2.0-2.5%
Chromium is a ferrite stabilizing element and an element that increases the curing ability, and the Ae3 temperature and the delta ferrite forming region temperature are adjusted by the amount thereof. Chromium also reacts with oxygen to form a dense and stable protective film of Cr 2 O 3 to increase high temperature oxidation resistance and corrosion resistance, but widen the delta ferrite formation temperature range. Delta ferrite may be formed during the casting process of steel with a high chromium content, which remains after heat treatment and adversely affects the properties of the steel.

したがって、本発明では、クロムの含量を２．０～２．５％の範囲に制限することが好ましく、より好ましくは２．１～２．４％の範囲に制限する。 Therefore, in the present invention, the chromium content is preferably limited to the range of 2.0 to 2.5%, more preferably to the range of 2.1 to 2.4%.

モリブデン（Ｍｏ）：０．９～１．１％
モリブデンは、硬化能を増加させ、フェライト安定化元素であると知られている。強力な固溶強化により高温クリープ寿命を増加させ、モリブデンがＭ（Ｃ，Ｎ）炭窒化物の形成金属元素として関与して炭窒化物を安定化させ、粗大化速度を著しく減少させる。これに対し、モリブデンの含量が増加すると、デルタフェライト形成温度領域を広げる可能性があり、鋼の鋳造過程でデルタフェライトが形成及び残留する恐れがある。残留したデルタフェライトは鋼材の特性に悪影響を与える。 Molybdenum (Mo): 0.9-1.1%
Molybdenum is known to be a ferrite stabilizing element with increased curability. The strong solid solution strengthening increases the high temperature creep life, and molybdenum participates as a forming metal element of M (C, N) carbonitride to stabilize the carbonitride and significantly reduce the coarsening rate. On the other hand, if the molybdenum content increases, the delta ferrite formation temperature region may be widened, and delta ferrite may be formed and remain in the steel casting process. The residual delta ferrite adversely affects the characteristics of the steel material.

したがって、モリブデンの含量を０．９～１．１％の範囲に制限することが好ましく、より好ましくは０．９５～１．０５％の範囲に制限する。 Therefore, the molybdenum content is preferably limited to the range of 0.9 to 1.1%, more preferably to the range of 0.95 to 1.05%.

バナジウム（Ｖ）：０．６５～１．０％
バナジウムはＭ（Ｃ，Ｎ）炭窒化物の形成元素の１つであるが、バナジウムの含量が増加するにつれて（Ｆｅ，Ｃｒ）２３Ｃ６炭化物形成の駆動力が小さくなり、結果として、（Ｆｅ，Ｃｒ）２３Ｃ６炭化物の形成を完全に抑えることができる。クロムの含量が２．０～２．５％であるクロム鋼において（Ｆｅ，Ｃｒ）２３Ｃ６炭化物の形成を抑えるためには、０．６５％以上のバナジウム合金が必要である。しかし、バナジウムの含量が１．０％を超える場合には、材料の生産工程に困難をきたすという問題がある。 Vanadium (V): 0.65 to 1.0%
Vanadium is one of the forming elements of M (C, N) carbide, but as the content of vanadium increases, the driving force for forming (Fe, Cr) 23 C 6 carbides decreases, resulting in (Fe). , Cr) 23 C 6 Carbide formation can be completely suppressed. In order to suppress the formation of (Fe, Cr) 23 C6 carbide in chromium steel having a chromium content of 2.0 to 2.5%, a vanadium alloy of 0.65% or more is required. However, when the content of vanadium exceeds 1.0%, there is a problem that the production process of the material becomes difficult.

したがって、バナジウムの含量を０．６５～１．０％の範囲に制限することが好ましく、より好ましくは０．６７～０．９８％の範囲に制限する。 Therefore, the vanadium content is preferably limited to the range of 0.65 to 1.0%, more preferably to the range of 0.67 to 0.98%.

ニッケル（Ｎｉ）：０．２５％以下（０％は除く）
ニッケルは、鋼の靭性を向上させる元素であり、低温靭性を劣化させることなく鋼の強度を増加させるために添加する。その含量を、０．２５％を超えて添加する場合には、ニッケルの添加によるコスト上昇をもたらす。 Nickel (Ni): 0.25% or less (excluding 0%)
Nickel is an element that improves the toughness of steel and is added to increase the strength of steel without degrading low temperature toughness. If the content is added in excess of 0.25%, the addition of nickel causes an increase in cost.

したがって、ニッケルの含量を０．２５％以下に制限することが好ましく、より好ましくは０．００５～０．２４％の範囲に制限する。 Therefore, the nickel content is preferably limited to 0.25% or less, more preferably 0.005 to 0.24%.

銅（Ｃｕ）：０．２０以下（０％は除く）
銅は、材料の硬化能を向上させる元素であり、熱処理後に鋼板が均質組織を有するようにするために添加する。しかし、その添加量が０．２０％を超える場合には、鋼板に割れが発生する可能性が高くなる。 Copper (Cu): 0.20 or less (excluding 0%)
Copper is an element that improves the curability of the material and is added to allow the steel sheet to have a homogeneous structure after heat treatment. However, if the amount added exceeds 0.20%, there is a high possibility that the steel sheet will be cracked.

したがって、銅の含量を０．２０％以下に制限することが好ましく、より好ましくは０．００５～０．１８％の範囲に制限する。 Therefore, the copper content is preferably limited to 0.20% or less, more preferably 0.005 to 0.18%.

ニオブ（Ｎｂ）：０．０７％以下（０％は除く）
ニオブは、Ｍ（Ｃ，Ｎ）炭窒化物の形成元素の１つである。また、スラブの再加熱時に固溶されていて、熱間圧延中にオーステナイト結晶粒の成長を抑え、後で析出されて鋼の強度を向上させる役割を果たす。しかし、ニオブを０．０７％を超えて過多添加する場合には、溶接性が低下する恐れがあり、結晶粒が必要以上に微細化する恐れがある。 Niobium (Nb): 0.07% or less (excluding 0%)
Niobium is one of the forming elements of M (C, N) carbonitride. In addition, it is dissolved during reheating of the slab and plays a role of suppressing the growth of austenite crystal grains during hot rolling and later precipitating to improve the strength of the steel. However, if niobium is added in excess of 0.07%, the weldability may deteriorate and the crystal grains may become finer than necessary.

したがって、ニオブの含量を０．０７％以下に制限することが好ましく、より好ましくは０．００５～０．０６％の範囲に制限する。 Therefore, the niobium content is preferably limited to 0.07% or less, more preferably 0.005 to 0.06%.

チタン（Ｔｉ）：０．０３％以下（０％は除く）
チタンも、ＴｉＮの形態となってオーステナイト結晶粒の成長を抑えるのに効果的な元素である。しかし、チタンを、０．０３％を超えて添加する場合には、粗大なＴｉ系析出物が形成され、材料の溶接に困難をきたす。 Titanium (Ti): 0.03% or less (excluding 0%)
Titanium is also an element that is effective in suppressing the growth of austenite crystal grains in the form of TiN. However, when titanium is added in an amount of more than 0.03%, coarse Ti-based precipitates are formed, which makes it difficult to weld the material.

したがって、チタンの含量を０．０３％以下に制限することが好ましく、より好ましくは０．００５～０．０２５％の範囲に制限する。 Therefore, the titanium content is preferably limited to 0.03% or less, more preferably 0.005 to 0.025%.

窒素（Ｎ）：０．０１５％以下（０％は除く）
窒素は、鋼中から工業的に完全に除去することが困難であるため、製造工程で許容可能な範囲である０．０１５％を上限にする。窒素は、オーステナイト安定化元素であると知られており、単なるＭＣ炭化物よりは、Ｍ（Ｃ，Ｎ）炭窒化物が形成された時に高温安定度が大きく向上し、鋼材のクリープ強度を効果的に増大させる役割を果たす。しかし、０．０１５％を超える場合には、ボロンと結合してＢＮを形成させ、欠陥の発生危険を増加させる。 Nitrogen (N): 0.015% or less (excluding 0%)
Since it is difficult to completely remove nitrogen from steel industrially, the upper limit is 0.015%, which is an acceptable range in the manufacturing process. Nitrogen is known to be an austenite stabilizing element, and its high temperature stability is greatly improved when M (C, N) carbonitrides are formed, and the creep strength of steel materials is more effective than that of simple MC carbides. Plays a role in increasing. However, if it exceeds 0.015%, it binds to boron to form BN and increases the risk of defect generation.

したがって、窒素の含量を０．０１５％以下に制限することが好ましい。 Therefore, it is preferable to limit the nitrogen content to 0.015% or less.

アルミニウム（Ａｌ）：０．０２５％以下（０％は除く）
アルミニウムはフェライト領域を拡大し、鋳造時に脱酸剤として添加される。クロム鋼は、他のフェライト安定化元素が多く合金されているため、アルミニウムの含量が増加する場合、Ａｅ３温度が過度に上昇する恐れがある。また、その添加量が０．０２５％を超える場合には、酸化物系介在物が多量形成され、素材の物性を低下させる。 Aluminum (Al): 0.025% or less (excluding 0%)
Aluminum expands the ferrite region and is added as a deoxidizer during casting. Since chromium steel is alloyed with a large amount of other ferrite stabilizing elements, the Ae3 temperature may rise excessively when the aluminum content increases. Further, when the addition amount exceeds 0.025%, a large amount of oxide-based inclusions are formed, which deteriorates the physical characteristics of the material.

したがって、アルミニウムの含量を０．０２５％以下に制限することが好ましく、より好ましくは０．００５～０．０２５％の範囲に制限する。 Therefore, the aluminum content is preferably limited to 0.025% or less, more preferably 0.005 to 0.025%.

ボロン（Ｂ）：０．００２％以下（０％は除く）
ボロンはフェライト安定化元素であり、極少量でも硬化能の増加に大きく寄与する。また、結晶粒界に容易に偏析され、結晶粒界の強化効果を与える。しかし、０．００２％を超えて添加する場合には、ＢＮが形成される可能性があり、これは、材料の機械的特性に悪影響を与える恐れがある。 Boron (B): 0.002% or less (excluding 0%)
Boron is a ferrite stabilizing element and contributes significantly to the increase in curability even in a very small amount. In addition, it is easily segregated at the grain boundaries and gives an effect of strengthening the crystal grain boundaries. However, if added in excess of 0.002%, BN may form, which may adversely affect the mechanical properties of the material.

したがって、ボロンの含量を０．００２％以下に制限することが好ましい。 Therefore, it is preferable to limit the boron content to 0.002% or less.

他に、残部はＦｅ及び不可避不純物からなる。通常の製造過程では、原料または周辺環境から意図しない不純物が不可避に混入されるため、これを排除することはできない。 In addition, the balance consists of Fe and unavoidable impurities. In the normal manufacturing process, unintended impurities are inevitably mixed in from the raw materials or the surrounding environment, and cannot be eliminated.

以下、クリープ特性に優れた本発明のクロムモリブデン鋼板の微細組織及び析出物について詳細に説明する。 Hereinafter, the fine structure and precipitates of the chromium molybdenum steel sheet of the present invention having excellent creep characteristics will be described in detail.

先ず、本発明の鋼板は、その素地の微細組織として、焼戻しマルテンサイト組織を含む。しかし、熱処理条件の如何によって、一部焼戻しベイナイト組織を含んでもよい。 First, the steel sheet of the present invention contains a tempered martensite structure as the fine structure of the substrate thereof. However, depending on the heat treatment conditions, a partially tempered bainite structure may be contained.

本発明の鋼板の微細組織には、（Ｆｅ，Ｃｒ）２３Ｃ６を含む直径２００ｎｍ以上の析出物が１個／μｍ２以下の個数範囲で存在することが好ましい。直径２００ｎｍ以上の析出物の個数が１個／μｍ２を超える場合には、粗大な炭化物によるクリープ特性の低下をもたらす恐れがある。 In the fine structure of the steel sheet of the present invention, it is preferable that precipitates having a diameter of 200 nm or more containing (Fe, Cr) 23 C 6 are present in a number range of 1 piece / μm 2 or less. When the number of precipitates having a diameter of 200 nm or more exceeds 1 piece / μm 2 , the creep characteristics may be deteriorated due to the coarse carbide.

これに対し、本発明の鋼板の微細組織には、直径２０ｎｍ以下の析出物が２０個／μｍ２以上の個数範囲で存在することが好ましい。直径２０ｎｍ以下の析出物の個数が２０個／μｍ２未満である場合には、微細な炭窒化物間の距離が非常に大きくなる。したがって、高温での転位移動と亜結晶粒の移動を効果的に防ぐことができず、クリープ特性の向上効果が大きくない。 On the other hand, in the fine structure of the steel sheet of the present invention, it is preferable that precipitates having a diameter of 20 nm or less are present in a number range of 20 pieces / μm 2 or more. When the number of precipitates having a diameter of 20 nm or less is less than 20 pieces / μm 2 , the distance between fine carbonitrides becomes very large. Therefore, the dislocation movement and the movement of subcrystal grains at high temperatures cannot be effectively prevented, and the effect of improving the creep characteristics is not great.

本発明において、直径２０ｎｍ以下の析出物は、（Ｖ，Ｍｏ，Ｎｂ，Ｔｉ）（Ｃ，Ｎ）を含むことができる。 In the present invention, the precipitate having a diameter of 20 nm or less can contain (V, Mo, Nb, Ti) (C, N).

次に、本発明の一実施形態によるクリープ強度に優れた析出硬化型クロムモリブデン鋼板の製造方法について説明する。 Next, a method for producing a precipitation hardening chrome molybdenum steel sheet having excellent creep strength according to an embodiment of the present invention will be described.

本発明の一クリープ強度に優れた析出硬化型クロムモリブデン鋼板の製造方法は、上述の組成の鋼スラブを仕上圧延温度がＡｒ３以上になるように熱間圧延して熱延鋼板を製造した後、冷却する工程と、冷却された熱延鋼板を、９００～１２００℃の温度範囲で１ｔ～３ｔ分［ｔ（ｍｍ）は、熱延鋼板の厚さである］間再加熱してオーステナイト化する工程と、オーステナイト化された熱延鋼板を常温に焼入れする工程と、焼入された熱延鋼板を６７５～８００℃の温度範囲で３０分～１２０分間焼戻しする工程と、を含む。 In the method for producing a precipitation-hardened chrome molybdenum steel sheet having an excellent creep strength of the present invention, a steel slab having the above composition is hot-rolled so that the finish rolling temperature becomes Ar3 or higher, and then a hot-rolled steel sheet is produced. A step of cooling and a step of reheating the cooled hot-rolled steel sheet for 1 to 3 tons [t (mm) is the thickness of the hot-rolled steel sheet] in a temperature range of 900 to 1200 ° C. to austenite. It includes a step of quenching the austenitic hot-rolled steel sheet to room temperature and a step of tempering the hard-rolled hot-rolled steel sheet in a temperature range of 675 to 800 ° C. for 30 minutes to 120 minutes.

先ず、本発明では、前述の組成成分を有する鋼スラブを仕上圧延温度がＡｒ３以上になるように熱間圧延して熱延鋼板を得る。このように、オーステナイト単相域で熱間圧延を行う理由は、組織の均一性を増加させるためである。 First, in the present invention, a steel slab having the above-mentioned composition components is hot-rolled so that the finish rolling temperature becomes Ar3 or higher to obtain a hot-rolled steel sheet. Thus, the reason for hot rolling in the austenite single-phase region is to increase the uniformity of the structure.

そして、本発明では、製造された熱延鋼板を常温に冷却する。 Then, in the present invention, the manufactured hot-rolled steel sheet is cooled to room temperature.

次いで、本発明では、冷却された熱延鋼板を再加熱してオーステナイト化する。この際、再加熱の温度範囲は９００～１２００℃であり、再加熱の時間は、熱延鋼板の厚さｔ（ｍｍ）に応じて１ｔ～３ｔ分の範囲で行うことが好ましい。 Then, in the present invention, the cooled hot-rolled steel sheet is reheated to be austenite. At this time, the temperature range of reheating is 900 to 1200 ° C., and the reheating time is preferably in the range of 1t to 3t depending on the thickness t (mm) of the hot-rolled steel sheet.

再加熱の温度が９００℃未満である場合には、熱間圧延後の冷却過程中に形成された不所望の炭化物を正しく再溶解することが困難である。これに対し、再加熱の温度が１２００℃を超える場合には、結晶粒の粗大化により特性が劣化する恐れがある。 When the reheating temperature is less than 900 ° C., it is difficult to correctly redissolve the undesired carbides formed during the cooling process after hot rolling. On the other hand, when the reheating temperature exceeds 1200 ° C., the characteristics may deteriorate due to the coarsening of the crystal grains.

再加熱の時間は、熱延鋼板の厚さをｔ（ｍｍ）としたときに、１ｔ～３ｔ分の範囲で行うことが好ましい。例えば、２０ｍｍの厚さを有する熱延鋼板を再加熱してオーステナイト化する場合、２０～６０分間行うことができる。再加熱の時間が１ｔ分未満である場合には、熱間圧延後の冷却過程中に形成された不所望の炭化物を正しく再溶解することが困難であるのに対し、３ｔ分を超える場合には、結晶粒の粗大化により特性が劣化する恐れがある。 The reheating time is preferably in the range of 1t to 3t when the thickness of the hot-rolled steel sheet is t (mm). For example, when a hot-rolled steel sheet having a thickness of 20 mm is reheated to austenite, it can be carried out for 20 to 60 minutes. When the reheating time is less than 1 ton, it is difficult to correctly redissolve the undesired carbides formed during the cooling process after hot rolling, whereas when it exceeds 3 tons. There is a risk that the characteristics of the product will deteriorate due to the coarsening of the crystal grains.

そして、本発明では、再加熱によりオーステナイト化された熱延鋼板を焼入れし、常温まで冷却させてマルテンサイト組織を得る。この際、基地組織の冷却時に、フェライト及びパーライト組織が形成されて基地の強度が大きく減少しないように注意する必要がある。 Then, in the present invention, the hot-rolled steel sheet that has been austenitized by reheating is quenched and cooled to room temperature to obtain a martensite structure. At this time, care must be taken so that the ferrite and pearlite structures are not formed and the strength of the base is not significantly reduced when the base structure is cooled.

続いて、本発明では、焼入れされた熱延鋼板を焼戻し（ｔｅｍｐｅｒｉｎｇ）する。この際、焼戻しの温度は６７５～８００℃、焼戻しの時間は３０分～１２０分として行った後、空冷することが好ましい。 Subsequently, in the present invention, the hardened hot-rolled steel sheet is tempered. At this time, it is preferable that the tempering temperature is 675 to 800 ° C. and the tempering time is 30 to 120 minutes, and then air cooling is performed.

焼戻しの温度が６７５℃未満である場合には、低い温度により、微細な炭窒化物の析出を時間内に誘導できない恐れがある。これに対し、焼戻しの温度が８００℃を超える場合には、焼戻しが材料の軟化を起こし、クリープ寿命を著しく低下させる恐れがある。 If the tempering temperature is less than 675 ° C., the low temperature may prevent the precipitation of fine carbonitrides from being induced in time. On the other hand, if the tempering temperature exceeds 800 ° C., the tempering may cause the material to soften and significantly reduce the creep life.

より好ましくは、焼戻しの温度を７００～７８０℃の範囲に制御する。 More preferably, the tempering temperature is controlled in the range of 700 to 780 ° C.

一方、焼戻しの時間が３０分未満である場合には、形成させようとする析出物が形成されない恐れがある。これに対し、焼戻しの時間が１２０分を超える場合には、析出物の粗大化及び材料の軟化を起こし、クリープ寿命を著しく低下させる恐れがある。 On the other hand, if the tempering time is less than 30 minutes, the precipitate to be formed may not be formed. On the other hand, if the tempering time exceeds 120 minutes, the precipitate may be coarsened and the material may be softened, which may significantly reduce the creep life.

以下、実施例を挙げて本発明を詳細に説明する。 Hereinafter, the present invention will be described in detail with reference to examples.

表１の合金組成及び２０ｍｍの厚さを有する熱延鋼板を用意した。次いで、熱延鋼板を１０００℃で１時間再加熱し、焼入れ処理して常温まで冷却した。続いて、冷却された鋼板を７３０℃で１時間焼戻しした後、常温まで空冷してＣｒ－Ｍｏ合金鋼を製造した。一方、表１において、鋼種１はＡＳＴＭ Ａ５４２Ｄの鋼組成であり、鋼種２－４は本発明の鋼組成成分を満たす鋼種である。 A hot-rolled steel sheet having the alloy composition shown in Table 1 and a thickness of 20 mm was prepared. Then, the hot-rolled steel sheet was reheated at 1000 ° C. for 1 hour, quenched and cooled to room temperature. Subsequently, the cooled steel sheet was tempered at 730 ° C. for 1 hour and then air-cooled to room temperature to produce a Cr—Mo alloy steel. On the other hand, in Table 1, the steel grade 1 is the steel composition of ASTM A542D, and the steel grade 2-4 is the steel grade satisfying the steel composition component of the present invention.

このように製造されたＣｒ－Ｍｏ合金鋼に対して、熱間圧延方向に、ＡＳＴＭ Ｅ１３９標準を活用してゲージ長１５ｍｍ、ゲージ径６ｍｍを有するクリープ試験片をそれぞれ製作した。米国ＡＴＳ社の２３２０クリープ試験装置を用いて、これらの試験片の高温クリープ寿命を評価し、その結果を図１に示した。また、比較のために、日本物質・材料研究機構（ＮＩＭＳ）から提供されたＡＳＴＭ Ａ５４２鋼材とＡＳＴＭ Ａ３８７ Ｇｒａｄｅ ９１鋼材のクリープ結果も図１に示した。 For the Cr-Mo alloy steel thus produced, creep test pieces having a gauge length of 15 mm and a gauge diameter of 6 mm were produced in the hot rolling direction by utilizing the ASTM E139 standard. The high temperature creep life of these test pieces was evaluated using a 2320 creep test device manufactured by ATS in the United States, and the results are shown in FIG. For comparison, the creep results of ASTM A542 steel and ASTM A387 Grade 91 steel provided by the National Institute for Materials Science (NIMS) are also shown in FIG.

また、ディラトメーターを用いて、オーステナイト化後における冷却速度による相変態を確認し、その結果を図２－図５に示した。なお、バナジウムの含量による（Ｆｅ，Ｃｒ）２３Ｃ６炭化物形成のギブス自由エネルギーの変化を、鋼種１に基づいてＴｈｅｒｍｏ－ＣａｌｃプログラムとＴＣＦＥ６データベースを用いて計算し、その結果を図６に示した。 In addition, using a dilatometer, the phase transformation due to the cooling rate after austenitization was confirmed, and the results are shown in FIGS. 2-Fig. The change in Gibbs free energy of (Fe, Cr) 23 C6 carbide formation due to vanadium content was calculated using the Thermo-Calc program and TCFE6 database based on steel grade 1, and the results are shown in FIG. ..

そして、製造された合金鋼試験片に対して走査型電子顕微鏡（ｓｃａｎｎｉｎｇ ｅｌｅｃｔｒｏｎ ｍｉｃｒｏｓｃｏｐｙ、ＳＥＭ）を活用して微細組織を観察し、その結果を図７に示した。 Then, the fine structure of the manufactured alloy steel test piece was observed by utilizing a scanning electron microscope (SEM), and the result is shown in FIG. 7.

Figure 2022509978000002
＊表１において、鋼種１－４は、それぞれＰ＜３０ｐｐｍ、Ｓ＜３０ｐｐｍ、及びＢ＜５ｐｐｍを含む。そして、他の成分の添加量の単位は重量％であり、残余成分はＦｅ及び不可避不純物である。
Figure 2022509978000002
* In Table 1, steel grades 1-4 contain P <30 ppm, S <30 ppm, and B <5 ppm, respectively. The unit of the addition amount of the other components is% by weight, and the residual components are Fe and unavoidable impurities.

図１に示すように、本発明のクロムモリブデン鋼板は、Ｃｒを９重量％含むＡＳＴＭ Ａ３８７ Ｇｒａｄｅ ９１鋼材よりも優れたクリープ寿命を有することが分かる。また、本発明の鋼組成成分を満たす鋼種２－４が、そうではない鋼種１に比べてより優れたクリープ特性を有することが確認できる。 As shown in FIG. 1, it can be seen that the chromium molybdenum steel sheet of the present invention has a superior creep life as that of the ASTM A387 Grade 91 steel sheet containing 9% by weight of Cr. Further, it can be confirmed that the steel grade 2-4 satisfying the steel composition component of the present invention has more excellent creep characteristics than the steel grade 1 which does not.

図２～図５から、鋼種１－４は何れも、１０００℃で１時間再加熱した後、焼入れ処理して常温まで冷却すると、その基地の微細組織がマルテンサイト組織を含むことが分かる。 From FIGS. 2 to 5, it can be seen that the microstructure of each of the steel grades 1-4 contains a martensite structure when it is reheated at 1000 ° C. for 1 hour, then quenched and cooled to room temperature.

一方、図６は、バナジウムの含量が増加するにつれて（Ｆｅ，Ｃｒ）２３Ｃ６炭化物形成の駆動力が小さくなり、結果として、（Ｆｅ，Ｃｒ）２３Ｃ６炭化物の形成を完全に抑制可能であるを示す。具体的に、クロムの含量が２．０～２．５重量％のクロム鋼において（Ｆｅ，Ｃｒ）２３Ｃ６炭化物の形成を抑えるためには、本発明で言及された焼戻しの温度範囲６７５～８００℃及びクリープ温度を考慮すると、０．６５重量％以上のバナジウム合金が必要であることが分かる。すなわち、本発明の鋼種２～４は、鋼種１と異なって何れも０．６５重量％以上のバナジウムを含んでいるため、（Ｆｅ，Ｃｒ）２３Ｃ６炭化物の形成を完全に抑制できることが分かる。 On the other hand, in FIG. 6, as the vanadium content increases, the driving force for the formation of (Fe, Cr) 23 C 6 carbide decreases, and as a result, the formation of (Fe, Cr) 23 C 6 carbide can be completely suppressed. Indicates that there is. Specifically, in order to suppress the formation of (Fe, Cr) 23 C 6 carbides in chromium steel having a chromium content of 2.0 to 2.5% by weight, the tempering temperature range 675 to mentioned in the present invention. Considering 800 ° C. and creep temperature, it can be seen that a vanadium alloy of 0.65% by weight or more is required. That is, it can be seen that since the steel grades 2 to 4 of the present invention contain vanadium of 0.65% by weight or more, unlike the steel grade 1 , the formation of (Fe, Cr) 23 C6 carbide can be completely suppressed. ..

図７は、１０００℃で１時間再加熱した後、焼入れ処理して常温まで冷却してから７３０℃で１時間焼戻しした鋼板の微細組織の観察結果を示した走査型電子顕微鏡写真であり、鋼種２～４は何れも、亜結晶粒界に沿って微細な炭窒化物が析出されたことが示されている。かかる炭窒化物が、高温での転位移動を効果的に妨げるだけでなく、亜結晶粒の移動も効果的に防ぎ、その安定性を確保することで、従来のクロム鋼に比べてクリープ特性が大きく改善されることが分かる。これに対し、鋼種１は、粗大な（Ｆｅ，Ｃｒ）２３Ｃ６炭化物が形成され、クリープ特性が鋼種２－４に比べて良くないことが分かる。 FIG. 7 is a scanning electron micrograph showing the observation results of the microstructure of the steel sheet that was reheated at 1000 ° C. for 1 hour, then quenched and cooled to room temperature, and then tempered at 730 ° C. for 1 hour. In each of 2 to 4, it is shown that fine carbonitrides were deposited along the subgrain boundaries. Such carbonitrides not only effectively prevent dislocation movement at high temperatures, but also effectively prevent the movement of subcrystal grains and ensure their stability, resulting in creep characteristics compared to conventional chromium steel. It can be seen that there is a great improvement. On the other hand, it can be seen that in the steel grade 1 , coarse (Fe, Cr) 23 C6 carbides are formed, and the creep characteristics are not as good as those in the steel grade 2-4.

本発明は、上述の実施例に限定されるものではない。また、実施例は例示的なものである。 The present invention is not limited to the above-mentioned examples. Moreover, the examples are exemplary.

Claims (9)

重量％で、Ｃ：０．１１～０．１５％、Ｓｉ：０．１０％以下（０％は除く）、Ｍｎ：０．３～０．６％、Ｓ：０．０１０％以下（０％は除く）、Ｐ：０．０１５％以下（０％は除く）、Ｃｒ：２．０～２．５％、Ｍｏ：０．９～１．１％、Ｖ：０．６５～１．０％、Ｎｉ：０．２５％以下（０％は除く）、Ｃｕ：０．２０％以下（０％は除く）、Ｎｂ：０．０７％以下（０％は除く）、Ｔｉ：０．０３％以下（０％は除く）、Ｎ：０．０１５％以下（０％は除く）、Ａｌ：０．０２５％以下（０％は除く）、Ｂ：０．００２％以下（０％は除く）、残部はＦｅ及び不可避不純物からなることを特徴とするクリープ強度に優れたクロムモリブデン鋼板。 By weight%, C: 0.11 to 0.15%, Si: 0.10% or less (excluding 0%), Mn: 0.3 to 0.6%, S: 0.010% or less (0%) Excludes), P: 0.015% or less (excluding 0%), Cr: 2.0 to 2.5%, Mo: 0.9 to 1.1%, V: 0.65 to 1.0% , Ni: 0.25% or less (excluding 0%), Cu: 0.20% or less (excluding 0%), Nb: 0.07% or less (excluding 0%), Ti: 0.03% or less (Excluding 0%), N: 0.015% or less (excluding 0%), Al: 0.025% or less (excluding 0%), B: 0.002% or less (excluding 0%), balance Is a chrome molybdenum steel plate having excellent creep strength, which is characterized by being composed of Fe and unavoidable impurities. 前記鋼板は、焼戻しマルテンサイトを含む微細組織を有することを特徴とする、請求項１に記載のクリープ強度に優れたクロムモリブデン鋼板。 The chrome molybdenum steel sheet having excellent creep strength according to claim 1, wherein the steel sheet has a fine structure containing tempered martensite. 前記鋼板の微細組織には、（Ｆｅ，Ｃｒ）２３Ｃ６を含む直径２００ｎｍ以上の析出物が１個／μｍ２以下の個数範囲で存在することを特徴とする、請求項２に記載のクリープ強度に優れたクロムモリブデン鋼板。 The creep according to claim 2, wherein deposits having a diameter of 200 nm or more containing (Fe, Cr) 23 C 6 are present in the fine structure of the steel sheet in a number range of 1 piece / μm 2 or less. Chromium molybdenum steel sheet with excellent strength. 前記鋼板の微細組織には、直径２０ｎｍ以下の析出物が２０個／μｍ２以上の個数範囲で存在することを特徴とする、請求項２に記載のクリープ強度に優れたクロムモリブデン鋼板。 The chrome molybdenum steel sheet having excellent creep strength according to claim 2, wherein precipitates having a diameter of 20 nm or less are present in the fine structure of the steel sheet in a number range of 20 pieces / μm 2 or more. 前記直径２０ｎｍ以下の析出物は、（Ｖ，Ｍｏ，Ｎｂ，Ｔｉ）（Ｃ，Ｎ）であることを特徴とする、請求項４に記載のクリープ強度に優れたクロムモリブデン鋼板。 The chromium molybdenum steel sheet having excellent creep strength according to claim 4, wherein the precipitate having a diameter of 20 nm or less is (V, Mo, Nb, Ti) (C, N). 重量％で、Ｃ：０．１１～０．１５％、Ｓｉ：０．１０％以下（０％は除く）、Ｍｎ：０．３～０．６％、Ｓ：０．０１０％以下（０％は除く）、Ｐ：０．０１５％以下（０％は除く）、Ｃｒ：２．０～２．５％、Ｍｏ：０．９～１．１％、Ｖ：０．６５～１．０％、Ｎｉ：０．２５％以下（０％は除く）、Ｃｕ：０．２０％以下（０％は除く）、Ｎｂ：０．０７％以下（０％は除く）、Ｔｉ：０．０３％以下（０％は除く）、Ｎ：０．０１５％以下（０％は除く）、Ａｌ：０．０２５％以下（０％は除く）、Ｂ：０．００２％以下（０％は除く）、残部はＦｅ及び不可避不純物からなる鋼スラブを仕上圧延温度がＡｒ３以上になるように熱間圧延して熱延鋼板を製造した後、冷却する工程と、
前記冷却された熱延鋼板を、９００℃～１２００℃の温度範囲で１ｔ～３ｔ分［ｔ（ｍｍ）は、熱延鋼板の厚さである］間再加熱してオーステナイト化する工程と、
前記オーステナイト化された熱延鋼板を常温に焼入れする工程と、
前記焼入された熱延鋼板を、６７５～８００℃の温度範囲で３０分～１２０分間焼戻しする工程と、を含んでなることを特徴とするクリープ強度に優れたクロムモリブデン鋼板の製造方法。 By weight%, C: 0.11 to 0.15%, Si: 0.10% or less (excluding 0%), Mn: 0.3 to 0.6%, S: 0.010% or less (0%) Excludes), P: 0.015% or less (excluding 0%), Cr: 2.0 to 2.5%, Mo: 0.9 to 1.1%, V: 0.65 to 1.0% , Ni: 0.25% or less (excluding 0%), Cu: 0.20% or less (excluding 0%), Nb: 0.07% or less (excluding 0%), Ti: 0.03% or less (Excluding 0%), N: 0.015% or less (excluding 0%), Al: 0.025% or less (excluding 0%), B: 0.002% or less (excluding 0%), balance Is a process of hot rolling a steel slab composed of Fe and unavoidable impurities so that the finish rolling temperature becomes Ar3 or higher to produce a hot-rolled steel sheet, and then cooling it.
A step of reheating the cooled hot-rolled steel sheet for 1 to 3 tons [t (mm) is the thickness of the hot-rolled steel sheet] in a temperature range of 900 ° C. to 1200 ° C. to austenite.
The process of quenching the austenitic hot-rolled steel sheet to room temperature and
A method for producing a chrome molybdenum steel sheet having excellent creep strength, which comprises a step of tempering the hardened hot-rolled steel sheet in a temperature range of 675 to 800 ° C. for 30 minutes to 120 minutes. 前記鋼板は、焼戻しマルテンサイトを含む微細組織を有し、その鋼板の微細組織には、（Ｆｅ，Ｃｒ）２３Ｃ６を含む直径２００ｎｍ以上の析出物が１個／μｍ２以下の個数範囲で存在することを特徴とする、請求項６に記載のクリープ強度に優れたクロムモリブデン鋼板の製造方法。 The steel sheet has a microstructure containing tempered martensite, and the fine structure of the steel sheet contains deposits containing (Fe, Cr) 23 C 6 and having a diameter of 200 nm or more in a range of 1 piece / μm 2 or less. The method for producing a chromium molybdenum steel sheet having excellent creep strength according to claim 6, wherein the chrome molybdenum steel sheet is present. 前記鋼板は、焼戻しマルテンサイトを含む微細組織を有し、その鋼板の微細組織には、直径２０ｎｍ以下の析出物が２０個／μｍ２以上の個数範囲で存在することを特徴とする、請求項６に記載のクリープ強度に優れたクロムモリブデン鋼板の製造方法。 The steel sheet has a microstructure containing tempered martensite, and the fine structure of the steel sheet is characterized in that precipitates having a diameter of 20 nm or less are present in a number range of 20 pieces / μm 2 or more. 6. The method for producing a chrome molybdenum steel sheet having excellent creep strength. 前記直径２０ｎｍ以下の析出物は、（Ｖ，Ｍｏ，Ｎｂ，Ｔｉ）（Ｃ，Ｎ）であることを特徴とする、請求項８に記載のクリープ強度に優れたクロムモリブデン鋼板の製造方法。 The method for producing a chromium molybdenum steel sheet having excellent creep strength according to claim 8, wherein the precipitate having a diameter of 20 nm or less is (V, Mo, Nb, Ti) (C, N).
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0297619A (en) * 1988-09-30 1990-04-10 Sumitomo Metal Ind Ltd Method for forming low-alloy steel for high-temperature service
JPH02217439A (en) * 1989-02-20 1990-08-30 Sumitomo Metal Ind Ltd High strength low alloy steel having excellent corrosion resistance and oxidation resistance
JP2001262268A (en) * 2000-01-13 2001-09-26 Sumitomo Metal Ind Ltd High strength low alloy heat resistant steel
JP2003286543A (en) * 2002-03-28 2003-10-10 Nippon Steel Corp HIGH-STRENGTH, LOW-Cr FERRITIC STEEL PIPE FOR BOILER SHOWING EXCELLENT LONG-TERM CREEP PROPERTIES AND ITS MANUFACTURING PROCESS

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0742546B2 (en) * 1989-08-16 1995-05-10 住友金属工業株式会社 Hot slab width sizing mold
JP3237137B2 (en) * 1991-08-12 2001-12-10 住友金属工業株式会社 High chromium ferritic heat-resistant steel with small decrease in strength of weld heat affected zone
JPH101739A (en) * 1996-06-11 1998-01-06 Nkk Corp Low alloy heat resistant steel, excellent in high temperature strength and weldability, and its production
JP3283768B2 (en) * 1996-10-28 2002-05-20 株式会社神戸製鋼所 High strength Cr-Mo steel TIG weld metal and TIG welding method
JP3525843B2 (en) * 2000-02-09 2004-05-10 住友金属工業株式会社 High strength low alloy heat resistant steel
US6641780B2 (en) * 2001-11-30 2003-11-04 Ati Properties Inc. Ferritic stainless steel having high temperature creep resistance
JP4074555B2 (en) * 2003-06-03 2008-04-09 新日本製鐵株式会社 Manufacturing method of steel for high strength low alloy boilers with excellent creep characteristics
KR101140651B1 (en) * 2010-01-07 2012-05-03 한국수력원자력 주식회사 High-Cr ferritic/martensitic steels having an improved creep resistance and preparation method thereof
DE102012011161B4 (en) * 2012-06-05 2014-06-18 Outokumpu Vdm Gmbh Nickel-chromium-aluminum alloy with good processability, creep resistance and corrosion resistance
KR101568523B1 (en) * 2013-12-24 2015-11-11 주식회사 포스코 Pressure vessel steel plate having excellent resistance of temper embrittlement and manufacturing method of the same
KR20150104348A (en) * 2014-03-05 2015-09-15 한국원자력연구원 Ferrite/martensitic oxide dispersion strengthened steel with excellent creep resistance and manufacturing method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0297619A (en) * 1988-09-30 1990-04-10 Sumitomo Metal Ind Ltd Method for forming low-alloy steel for high-temperature service
JPH02217439A (en) * 1989-02-20 1990-08-30 Sumitomo Metal Ind Ltd High strength low alloy steel having excellent corrosion resistance and oxidation resistance
JP2001262268A (en) * 2000-01-13 2001-09-26 Sumitomo Metal Ind Ltd High strength low alloy heat resistant steel
JP2003286543A (en) * 2002-03-28 2003-10-10 Nippon Steel Corp HIGH-STRENGTH, LOW-Cr FERRITIC STEEL PIPE FOR BOILER SHOWING EXCELLENT LONG-TERM CREEP PROPERTIES AND ITS MANUFACTURING PROCESS

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