JPS62139816A - Manufacture of high tension and toughness steel plate - Google Patents
Manufacture of high tension and toughness steel plateInfo
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- JPS62139816A JPS62139816A JP28106985A JP28106985A JPS62139816A JP S62139816 A JPS62139816 A JP S62139816A JP 28106985 A JP28106985 A JP 28106985A JP 28106985 A JP28106985 A JP 28106985A JP S62139816 A JPS62139816 A JP S62139816A
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- steel
- toughness
- plate
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Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
じん性のすぐれた非調質高張力鋼板の製造方法に関し、
とくに加熱圧延条件と冷却条件を制御することにより、
じん性の劣化なしに高強度化して、しかも板表面から中
心まで均一な機械的性質を具備させることについての開
発研究の成果を以下に述べる。[Detailed Description of the Invention] (Industrial Application Field) Regarding a method for manufacturing a non-tempered high tensile strength steel plate with excellent toughness,
In particular, by controlling hot rolling conditions and cooling conditions,
The results of our research and development efforts to increase strength without deteriorating toughness and provide uniform mechanical properties from the surface to the center of the plate are described below.
（従来の技術）
加熱圧延条件及び冷却条件の適当な組合せにより非調質
高張力鋼板を製造する方法についてはよく知られている
。たとえば特公昭５５−３００４７号公報に示すところ
によればＣ： ０．０３〜０．２０ｗｔ％（以下単に％
と示す） 、Ｓｔ ： ０．０５〜０．６０％、Ｍｎ二
０．５０〜１．８％を基本成分とし、これに特殊元素を
添加する場合には０．１０％以下のＡｌ．０．５０％以
下のＣｕ、１％以下の旧、０．５０％以下のＣｒ、０．
０３％以下のＭＯｌｏ、２０％以下の■、０．１０％以
下のＮｂ、０．１０％以下のＴｉを１ 、ｆｆｆｉ又は
２種含有させ残部は鉄および不可避的不純物よりなる鋼
を８００〜■０００°Ｃの温度範囲に加熱後５０％以上
の加工度を施し８００℃以下の温度で熱間圧延終了後直
ちに２・〜１５°Ｃ／ｓｅｃの冷却速度で６００°Ｃ以
下の任意の温度まで冷却することによりじん性を劣化さ
せず高強度を附与した非３Ｉ］ｉ高張力鋼板が製造でき
るとしている。(Prior Art) A method for producing a non-thermal high tensile strength steel plate by appropriately combining hot rolling conditions and cooling conditions is well known. For example, according to Japanese Patent Publication No. 55-30047, C: 0.03 to 0.20 wt% (hereinafter simply %
), St: 0.05-0.60%, Mn2: 0.50-1.8% as basic components, and when special elements are added to this, Al. 0.50% or less Cu, 1% or less old, 0.50% or less Cr, 0.
Steel containing 0.03% or less MOlo, 20% or less ■, 0.10% or less Nb, and 0.10% or less Ti, with the balance consisting of iron and inevitable impurities. After heating in the temperature range of 000°C, the degree of working is 50% or more, and immediately after hot rolling at a temperature of 800°C or less, the cooling rate is 2-15°C/sec to any temperature below 600°C. It is said that by cooling, it is possible to produce a non-3I]i high-strength steel sheet that has high strength without deteriorating its toughness.
（発明が解決しようとする問題点）
しかし上掲公報の開示に代表される公知の製造方法を工
業的規模の鋼板製造ラインに適用した場合に、下記に示
すような技術的問題点があり、必ずしも目的とする高張
力高靭性鋼板が製造できるとはかぎらないことが解明さ
れた。(Problems to be Solved by the Invention) However, when the known manufacturing method as typified by the disclosure in the above publication is applied to an industrial scale steel sheet manufacturing line, there are technical problems as shown below. It has become clear that it is not always possible to produce the desired high-tensile, high-toughness steel plate.
（１）加熱温度がＡｃ３近傍であっても完全にオーステ
ナイト化を完了しない限り、圧延・冷却後に異常組織が
出現し、じん性が劣化すること。(1) Even if the heating temperature is around Ac3, unless austenitization is completely completed, an abnormal structure will appear after rolling and cooling, and the toughness will deteriorate.
（２）全加工度を大きくしたとしてもとくに未再結晶域
での加工度が小さい場合には変態後の結晶粒径が十分微
細化せず、十分なしん性が得られないこと。(2) Even if the total working degree is increased, especially if the working degree in the non-recrystallized region is small, the crystal grain size after transformation will not be sufficiently refined and sufficient toughness will not be obtained.
（３）圧延終了温度、冷却開始温度の管理が不十分な場
合には強度上昇量の制御ができず、特に板厚が厚（なる
と冷却速度が異なる板表面と中心に大きな強度差を生じ
ること。(3) If the rolling end temperature and cooling start temperature are insufficiently controlled, the amount of increase in strength cannot be controlled, and especially when the plate thickness is thick (the cooling rate differs, a large strength difference will occur between the plate surface and the center). .
（４）冷却停止温度が高すぎる場合には十分な強度上昇
効果が得られず、また逆に低すぎる場合には低温変態組
織を生成しじん性が劣化すること。(4) If the cooling stop temperature is too high, a sufficient strength-increasing effect cannot be obtained; on the other hand, if it is too low, a low-temperature transformed structure is generated and the toughness is deteriorated.
したがって加熱条件、圧延条件、冷却条件の管理を厳密
に行い、加熱時のオーステナイト粒成長挙動の制御、オ
ーステナイト低温域圧延によるフェライト変態の促進、
及び冷却時の第２相変態挙動の制御による、じん性にす
ぐれとくに厚さ方向に均一な強度を有する高張力鋼板の
製造技術を確立することが必要であり、しかも工業的規
模での生産を考えた場合多少の条件変動があっても強度
・じん性の変化が小さくなるような制御圧延・制御冷却
方法が望まれるわけ、である。Therefore, heating conditions, rolling conditions, and cooling conditions are strictly controlled to control austenite grain growth behavior during heating, promote ferrite transformation by rolling austenite in a low temperature range,
It is necessary to establish a manufacturing technology for high-strength steel sheets with excellent toughness and uniform strength in the thickness direction by controlling the second phase transformation behavior during cooling. Considering this, it is desirable to have a controlled rolling/cooling method that minimizes changes in strength and toughness even if there are slight variations in conditions.
（問題点を解決するための手段）
この発明は炭素鋼または低合金を９３０〜１０６０°Ｃ
の温度範囲に加熱後、未再結晶オーステナイト域で７０
％以上の加工度を施し、板厚中心部の温度が７５０〜８
５０°Ｃの温度範囲にて熱間圧延を終了し、板厚中心部
で７５０℃以上の温度から、板厚中心部における１〜８
°Ｃ／秒の冷却速度範囲で冷却を行い、板厚中心部の温
度が２００〜５００°Ｃの温度範囲にて冷却を停止する
ことを特徴とする高張力高じん性鋼板の製造方法である
。(Means for Solving the Problems) This invention heats carbon steel or low alloy at a temperature of 930 to 1060°C.
70 in the unrecrystallized austenite region after heating to a temperature range of
The temperature at the center of the plate thickness is 750~8.
Hot rolling is completed in a temperature range of 50°C, and from a temperature of 750°C or higher at the center of the plate thickness, 1 to 8 at the center of the plate thickness.
A method for producing a high tensile strength steel sheet, characterized in that cooling is performed at a cooling rate range of °C/sec, and cooling is stopped when the temperature at the center of the sheet thickness is in the temperature range of 200 to 500 °C. .
この製造方法は炭素鋼又は低合金鋼が化学成分としてＡ
ｌ：０．００５〜０．０８ｗｔ％、Ｎ ：０．００５ｗ
ｔ％以下を含有するか又は炭素鋼又は低合金鋼が化学成
分としてＡｌ：０．００５〜０．０８ｗｔ％、Ｎ：０．
００５ｉｖｔ％以下を含有しさらに全希土類元素：０．
００３〜０．０３ｗｔ％及び／又はＺｒ：０．００３〜
０．０６ｗｔ％を含有する場合においてとくに好適であ
り、またこれらの成分以外の一般的な鋼中成分の組成範
囲については次のとおりである。This manufacturing method uses carbon steel or low alloy steel as a chemical component.
l: 0.005-0.08wt%, N: 0.005w
t% or less, or carbon steel or low alloy steel contains Al: 0.005 to 0.08 wt%, N: 0.
0.005ivt% or less, and further contains total rare earth elements: 0.
003~0.03wt% and/or Zr: 0.003~
It is particularly suitable when the content is 0.06 wt%, and the composition ranges of general components in steel other than these components are as follows.
Ｃ：ｏ、ｏｉ〜０．２０ｗｔ％ Ｓｉ：０．１〜０．
５ ｗｔ％Ｍｎ ： ０．６〜２．Ｏｗｔ％
発明者らは種々の加熱条件、圧延条件、冷却条件での加
工熱処理実験をくりかえした結果炭素鋼または低合金鋼
の組織、強度しん性の変化について以下のような知見を
得た。C: o, oi~0.20wt% Si: 0.1~0.
5 wt%Mn: 0.6-2. Owt% As a result of repeated processing heat treatment experiments under various heating conditions, rolling conditions, and cooling conditions, the inventors obtained the following findings regarding changes in the structure and strength toughness of carbon steel or low alloy steel.
（１）加熱温度を９３０℃〜１０６０°Ｃに制御するこ
とにより加熱時の組織は完全にオーステナイト化し、し
かもオーステナイト粒の粗大化も起こらない。(1) By controlling the heating temperature to 930°C to 1060°C, the structure during heating is completely austenitized, and no coarsening of austenite grains occurs.
また特に９７０〜１０３０℃の温度範囲においては均一
なオーステナイト粒が得られる。Moreover, uniform austenite grains can be obtained especially in the temperature range of 970 to 1030°C.
（２） フェライト粒核形成サイトとなるオーステナ
イト中への変形帯を必要量生成させるためには未再結晶
域での累積圧下率を７０％以上にする必要がある。(2) In order to generate the necessary amount of deformation bands in austenite that serve as ferrite grain nucleation sites, the cumulative reduction rate in the non-recrystallized region must be 70% or more.
（３） 板厚中心部が未再結晶オーステナイト、表層
部がオーステナイト＋フェライト状態から強制冷却する
と、水量、冷却時間を適正に制御することにより、表層
部は微細フェライト士パーライト、中心部は微細フェラ
イト＋ベイナイト組織となり、均一な強度が得られる。(3) When forced cooling is performed from a state where the central part of the plate thickness is unrecrystallized austenite and the surface part is austenite + ferrite, by appropriately controlling the amount of water and cooling time, the surface part becomes fine ferrite or pearlite, and the center part becomes fine ferrite. + It becomes a bainite structure, and uniform strength is obtained.
この発明は以上の発見事実に立脚している。この発明で
は、熱間圧延終了温度、冷却開始温度、冷却速度及び冷
却停止温度につき、板厚中心部における値をもって、制
御要因とし、そのためこれらの値は
のようにして正しく把握することが重要である。This invention is based on the above findings. In this invention, the values at the center of the plate thickness are used as control factors for the hot rolling end temperature, cooling start temperature, cooling rate, and cooling stop temperature, and it is therefore important to correctly understand these values as follows. be.
（作 用）
圧延条件について、
大量生産の場において、加熱時に綱片の各部で完全にオ
ーステナイト化するためには加熱温度の下限を９３０″
Ｃとする必要がある。また加熱時のオーステナイト粒の
粗大化を防止するためには加熱温度の上限を１０６０℃
にする必要がある。またそのうち炭窒化物が固溶し均一
で微細なオーステナイト粒を得ることができる９７０〜
１０３０℃の加熱範囲がとくにのぞましい。(Function) Concerning rolling conditions, in mass production, in order to completely austenite each part of the strip during heating, the lower limit of the heating temperature should be set to 930".
It needs to be C. In addition, in order to prevent the austenite grains from becoming coarse during heating, the upper limit of the heating temperature should be set to 1060°C.
It is necessary to In addition, carbonitrides are dissolved in solid solution and uniform and fine austenite grains can be obtained from 970~
A heating range of 1030°C is particularly desirable.
次に十分な低温じん性を得るためには、加熱時のオース
テナイト粒の微細化のみでは不十分であり、オーステナ
イト粒界以外にもフェライトの核形成サイトを導入して
、フェライト核形成能を高める必要がある。このために
は未再結晶域加工度を７０％以上としオーステナイト中
の変形帯密度を冑くする必要がある。Next, in order to obtain sufficient low-temperature toughness, it is not sufficient to refine the austenite grains during heating, but to increase the ferrite nucleation ability by introducing ferrite nucleation sites other than the austenite grain boundaries. There is a need. For this purpose, it is necessary to increase the degree of working in the non-recrystallized region to 70% or more and to reduce the density of deformation bands in austenite.
未再結晶域の加工度が７０％以下では変形帯密度の十分
高い値が得られない。If the working degree of the non-recrystallized region is 70% or less, a sufficiently high value of the deformation band density cannot be obtained.
板厚方向の強度変動を小さくし均一な鋼板を得るために
は圧延終了温度、そしてさらには冷却開始温度を制御し
表面と中心部の冷却速度差にともなう強度変動量を冷却
前の組織の差にともなう焼入性の違いにより補償する必
要がある。In order to reduce strength fluctuations in the thickness direction and obtain a uniform steel sheet, the rolling end temperature and even the cooling start temperature are controlled to reduce the strength fluctuations due to the difference in cooling rate between the surface and the center by controlling the difference in the structure before cooling. It is necessary to compensate for the difference in hardenability caused by the difference in hardenability.
これらの温度の制御は、冷却速度のもっとも遅い板厚中
心部で行う必要がある。These temperatures must be controlled at the center of the plate thickness, where the cooling rate is slowest.
十分な低温じん性を得るための圧延終了温度は板厚中心
部の温度の上限を８５０℃にする必要がありそれという
のは８５０’Ｃをこえると未再結晶域圧延の硬化が十分
発揮されずじん性が劣化する。また冷却による強度上昇
効果を十分に発揮させるためには圧延終了時の板厚中心
部の温度の下限を７５０℃にする必要があり、７５０℃
よりも低くなった場合にはオーステナイト−フェライト
域でのフェライト加工により変態が起こりやすくなり、
焼入性が低下し十分な強度上昇効果は得られない。In order to obtain sufficient low-temperature toughness, the upper limit of the rolling end temperature at the center of the plate thickness must be 850°C, because if the temperature exceeds 850°C, the hardening of the rolling in the non-recrystallized region will be fully exerted. The toughness deteriorates. In addition, in order to fully demonstrate the strength increasing effect of cooling, the lower limit of the temperature at the center of the plate thickness at the end of rolling must be 750°C.
If the value is lower than , transformation is likely to occur due to ferrite processing in the austenite-ferrite region,
Hardenability deteriorates and a sufficient strength increase effect cannot be obtained.
とくに板厚が厚い場合には表層部はオーステナイト−フ
ェライト２相域となるが、冷却速度を速くして焼入性の
低下を補償できる。この場合には表層部は微細フェライ
ト＋パーライト、中心部は微細なフェライト＋ベイナイ
トとなるが、両者のフェライト強度の差とパーライト、
ベイナイト強度差は中心部の圧延終了温度が７５０℃以
上ではうまくバランスし板厚方向に均一な強度分布が得
られることによる。In particular, when the plate thickness is thick, the surface layer becomes an austenite-ferrite two-phase region, but the decrease in hardenability can be compensated for by increasing the cooling rate. In this case, the surface layer will be fine ferrite + pearlite, and the center will be fine ferrite + bainite, but due to the difference in ferrite strength between the two, pearlite,
The difference in bainite strength is due to the fact that when the rolling end temperature in the center is 750° C. or higher, it is well balanced and a uniform strength distribution in the thickness direction is obtained.
従って板厚中心部での圧延終了温度は好ましくは８００
〜８５０℃に限定され、この温度範囲においては冷却後
の組織が表面、中心ともに微細フェライト＋ベイナイト
となり、強度のみならずＵ織も均一となる。Therefore, the rolling end temperature at the center of the plate thickness is preferably 800.
The temperature is limited to ~850°C, and in this temperature range, the structure after cooling becomes fine ferrite + bainite on both the surface and center, and not only the strength but also the U weave becomes uniform.
冷却条件について
圧延終了温度の限定に関してのべたところと同し技術的
な意味合いで冷却開始温度は７５０℃以上、好ましくは
８００°Ｃ以上に限定される。Regarding the cooling conditions, the cooling start temperature is limited to 750°C or higher, preferably 800°C or higher, for the same technical reasons as described above regarding the limitation of the rolling end temperature.
冷却による強度上昇効果を十分発揮させるために板厚中
心部冷却速度の下限を１°Ｃ／秒にする必要がある。１
’Ｃ／秒未満では冷却による強度上昇効果が顕著でない
。In order to fully exhibit the strength-increasing effect of cooling, it is necessary to set the lower limit of the cooling rate at the center of the plate thickness to 1°C/sec. 1
Below 'C/sec, the strength increasing effect due to cooling is not significant.
また本発明での冷却停止温度２００〜５００℃において
形状のすぐれた鋼板を製造するためには冷却速度の上限
を８℃／秒にする必要がある。８℃／秒超で２００〜５
００℃まで冷却すると膜沸騰から核沸騰への遷移による
微妙な温度のバランスのくずれにより、ひずみを生じ形
状が悪くなる。Further, in order to produce a steel plate with an excellent shape at a cooling stop temperature of 200 to 500°C in the present invention, it is necessary to set the upper limit of the cooling rate to 8°C/sec. 200-5 at over 8℃/sec
When cooled to 00°C, the delicate temperature balance is disrupted due to the transition from film boiling to nucleate boiling, causing distortion and deteriorating the shape.
板厚中心部での冷却停止温度を２００〜５００°Ｃに限
定したのは以下の理由による。The reason why the cooling stop temperature at the center of the plate thickness was limited to 200 to 500°C is as follows.
冷却停止温度が５００℃超では冷却による強度上昇効果
が顕著ではない。また冷却停止温度が２００°Ｃ未満で
は低温変態組織が多量に生成されしん１生が劣化する。When the cooling stop temperature exceeds 500°C, the effect of increasing strength due to cooling is not significant. Further, if the cooling stop temperature is less than 200°C, a large amount of low-temperature transformed structure is generated and the steel quality deteriorates.
板厚が厚い場合には表層部は一時的には室温付近まで冷
却されるが、復熱効果により温度が上昇するため、中心
部の温度が２００°Ｃ以上であれば多量の低温変態組織
の生成をさけることができる。When the plate is thick, the surface layer is temporarily cooled to around room temperature, but the temperature rises due to the recuperation effect, so if the temperature at the center is over 200°C, a large amount of low-temperature transformed structure will be formed. You can avoid generation.
この発明は特にこれまで板厚方向での均一な機械的性質
を得ることが困難であった板厚６０１１以上の鋼板に有
効である。This invention is particularly effective for steel plates with a thickness of 6011 mm or more, for which it has been difficult to obtain uniform mechanical properties in the thickness direction.
この発明は炭素鋼または低合金鋼を対象とし、その成分
組成については次の技術的意義をもつ。This invention targets carbon steel or low alloy steel, and its composition has the following technical significance.
Ｃは０．０１ｗｔ％未満では鋼の強度が低下し、母材の
熱影響部（以下１１ＡＺと記す）の軟化が顕著となる一
方、０゜２０ｗｔ％を越えると母材靭性の劣化および溶
接部の硬化、耐割れ性の劣化が大きくなることがらＣの
適正範囲は０．０１〜０．２．ｗｔ％である。If C is less than 0.01wt%, the strength of the steel will decrease and the heat-affected zone (hereinafter referred to as 11AZ) of the base metal will become noticeably softened, while if it exceeds 0.20wt%, the toughness of the base metal will deteriorate and the weld zone will deteriorate. The appropriate range of C is 0.01 to 0.2. It is wt%.
Ｓｉは０．１ ｗｔ％未満では母材じん性の劣化を招き
、一方０．５ ｗｔ％を越えると綱の清浄度が低下して
じん性劣化をまねくことから、Ｓｉの適正範囲は０．１
〜０．５ ｗｔ％にする必要がある。If Si is less than 0.1 wt%, it will cause a deterioration in the toughness of the base material, while if it exceeds 0.5 wt%, the cleanliness of the rope will decrease and the toughness will deteriorate, so the appropriate range for Si is 0. 1
~0.5 wt%.
Ｍｎは０．６ ｗｔ％未満では鋼の強度、じん性が劣化
しＩＩＡＺが軟化する傾向にある。しかし２ｗｔ％を越
えるとＩＩＡＺのじん性が低下するため、Ｍｎの適正範
囲は０．６〜２．０賀ｔ％である。When Mn is less than 0.6 wt%, the strength and toughness of the steel tend to deteriorate and IIAZ tends to soften. However, if it exceeds 2 wt%, the toughness of IIAZ decreases, so the appropriate range for Mn is 0.6 to 2.0 wt%.
さらにこの発明の効果をより有効に発揮させるため鋼の
化学成分のうちＡｌとＮは、それぞれ八ｌ：０．００５
〜０．０８％、Ｎ ：０．００５％以下が望ましい。鋼
片を加熱前にＡＩとＮを固溶させ９３０〜１０６０’ｃ
の温度範囲での加熱を行ったときＡＩＮを微細に析出さ
せることによりオーステナイト組織を微細化かつ均一化
させるというのがその技術内容であるが、Ａｌ量、Ｎｌ
の上限は鋼片の冷却中におけるＡＩＮの析出を防止する
ためであり、Ａｌ量の下限は加熱時に有効なＡＩＮの体
積分率を確保するためである。Furthermore, in order to more effectively exhibit the effects of this invention, among the chemical components of steel, Al and N are each 8l:0.005.
~0.08%, N: 0.005% or less is desirable. Before heating the steel piece, AI and N are dissolved in solid solution to 930~1060'c.
The technology is to make the austenite structure finer and more uniform by finely precipitating AIN when heated in a temperature range of
The upper limit of the amount of Al is to prevent precipitation of AIN during cooling of the steel billet, and the lower limit of the amount of Al is to ensure an effective volume fraction of AIN during heating.
Ａｌ：０．００５〜０．０８ｗｔ％、Ｎ量：０．００５
ｗｔ％以下にすると鋼片の冷却速度が遅くなるような大
型素材についてもＡＩＮの析出が防止され、加熱時の微
細析出物生成が容易になる。Al: 0.005-0.08wt%, N amount: 0.005
When the content is less than wt%, precipitation of AIN is prevented even in large materials where the cooling rate of the steel billet is slow, and formation of fine precipitates during heating is facilitated.
上記成分にさらに希土類元素及び／又はＺｒを適量加え
ることによりじん性の改善効果が著しくなる。By further adding appropriate amounts of rare earth elements and/or Zr to the above components, the effect of improving toughness becomes remarkable.
すなわち微細な炭窒化物を加熱時に生成してオーステナ
イトを微細化するとともにフェライト核形成サイトとな
り未再結晶域圧延の効果をより有効に発揮させるからで
ある。希土類元素量は０．００３〜０．０３ｗｔ％また
Ｚｒは０．００３〜０．０６ｗｔ％が好ましく、これら
添加量の上限は鋼片冷却時の析出防止のためであり、下
限は加熱時に十分な体積分率を確保するためである。That is, fine carbonitrides are generated during heating, which refine the austenite and also serve as ferrite nucleation sites, making the effect of rolling in the non-recrystallized region more effective. The amount of rare earth elements is preferably 0.003 to 0.03 wt%, and the amount of Zr is preferably 0.003 to 0.06 wt%. This is to ensure the volume fraction.
（実施例）
実施例１
供試鋼の成分を表１に示し、この供試鋼のオーステナイ
ト未再結晶温度域は８７５℃である。(Example) Example 1 The composition of the test steel is shown in Table 1, and the austenite non-recrystallization temperature range of this test steel is 875°C.
表２に示す加熱、熱間圧延、冷却条件で板厚６０■識の
厚板を製造した。A thick plate having a thickness of 60 mm was manufactured under the heating, hot rolling, and cooling conditions shown in Table 2.
板厚中心部での機械的性質を表２に示す。Table 2 shows the mechanical properties at the center of the plate thickness.
表２から加熱温度が１１００℃（番号１）あるいは８５
０℃（番号４）と加熱温度の上限あるいは下限をはずれ
る場合には、−７５℃あるいは一５５℃のｖＴｒｓしか
得られないが、１０２０℃（番号２）あるいは９６０℃
（番号３）の場合はｖＴｒｓが一１１０℃以下となりす
ぐれた低温じん性を示す。また好適範囲である１０２０
℃では引張強さ５６ｋｇｆ／ａｍ２と高い値を示す。From Table 2, the heating temperature is 1100℃ (number 1) or 85℃.
If the heating temperature is outside the upper or lower limit of 0°C (number 4), only -75°C or -55°C vTrs can be obtained;
In the case of (number 3), vTrs is 1110°C or less, indicating excellent low-temperature toughness. Also, 1020 is a suitable range.
℃ shows a high tensile strength of 56 kgf/am2.
未再結晶域圧下率を５０％に減少させる（番号５）とｖ
Ｔｒｓが一７０℃となりじん性が劣化する。Decrease the unrecrystallized area reduction rate to 50% (number 5) and v
Trs becomes 170°C and the toughness deteriorates.
圧延終了温度が８７５℃（番号６）と高い場合にはｖＴ
ｒｓ −６５℃となり十分な低温じん性が得られない。If the rolling end temperature is as high as 875°C (number 6), vT
rs -65°C, and sufficient low-temperature toughness cannot be obtained.
また圧延終了温度が７１５℃と低くなった場合（番号８
）には低温じん性はすぐれているが、引張強さが４８ｋ
ｉｒｆ／ｍｍ２と十分な冷却による強度上昇がみられな
い。Also, when the rolling end temperature is as low as 715℃ (number 8
) has excellent low-temperature toughness, but its tensile strength is only 48K.
irf/mm2, and no increase in strength was observed due to sufficient cooling.
圧延終了温度が７６０℃で＾ｒ、付近にあっても７５０
°Ｃ以上で冷却（番号７）すれば５２ｋｇｆ／龍２と十
分な引張強さが得られるのに反し冷却開始温度が７１２
°Ｃと低くなる（番号９）と引張強度は４９ｋｇｆ／龍
２に下り冷却による強度上昇効果が顕著でなくなる。The rolling end temperature is 760℃^r, even if it is around 750℃
If you cool it above °C (number 7), you can obtain a sufficient tensile strength of 52 kgf/Ryu2, but the cooling start temperature is 712 kgf/Ryu2.
When the temperature becomes low (number 9), the tensile strength decreases to 49 kgf/Ryu 2, and the strength increasing effect due to cooling becomes less noticeable.
圧延後空冷（番号１０）シた場合には当然のことながら
引張強さは４６ｋｇｆ／ｍｍ２と低いが２．５℃／秒の
速度で強制冷却（番号１１）を行うことにより引張強さ
は５１ｋｇｆ／ｗ２と５ｋｇｆ／ｓｎ２もの強度上昇が
ある。Naturally, when air cooling (No. 10) is performed after rolling, the tensile strength is as low as 46 kgf/mm2, but by forced cooling at a rate of 2.5°C/sec (No. 11), the tensile strength is 51 kgf. /w2 and 5kgf/sn2 strength increase.
冷却停止温度が５５０℃（番号１２）と高くなると強度
上昇効果が得られない。また室温まで冷却するとく番号
１４）じん性が劣化するが、冷却停止温度を２５０℃ま
で上昇させることによりじん性の劣化はみられずｖＴｒ
ｓ −１０８℃とすぐれた低温じん性を示す。If the cooling stop temperature is as high as 550° C. (number 12), no strength increase effect can be obtained. In addition, when cooling to room temperature, the toughness deteriorates (No. 14), but by increasing the cooling stop temperature to 250°C, no deterioration in toughness was observed and vTr
Shows excellent low-temperature toughness at -108°C.
実施例２
表３に成分を示す供試鋼を、１０００℃に加熱後８７５
℃〜７９０℃または圧延終了温度の未再結晶域で７６％
の加工を行った後、板厚中心での圧延終了温度を表４に
示す条件で変化させ６０龍の厚板に圧延後、ただちに冷
却を開始し、中心部の冷却速度５℃／秒で４００℃まで
冷却した。表面下５龍と中心部の引張強さを表４にあわ
せ示す。Example 2 A test steel whose composition is shown in Table 3 was heated to 1000°C and then heated to 875°C.
℃~790℃ or 76% in non-recrystallized area of rolling end temperature
After processing, the rolling end temperature at the center of the plate thickness was varied under the conditions shown in Table 4, and after rolling to a thick plate of 60 mm, cooling was immediately started, and the cooling rate at the center was 5℃/sec. Cooled to ℃. Table 4 also shows the tensile strength of the 5 dragons below the surface and the center.
表３
表４
表４に示すように圧延終了温度が７５０〜８５０℃の範
囲である番号２．３．４は表層部と中心部の引張強さの
差が２ｋｇｆ／ｍｍ”と小さいが、圧延終了温度が８７
５°Ｃのように高すぎる場合は強度差が５ｋｇｆ／鳳冒
２と大きくなる。Table 3 Table 4 As shown in Table 4, for numbers 2.3.4 whose rolling end temperature is in the range of 750 to 850°C, the difference in tensile strength between the surface layer and the center is as small as 2 kgf/mm. End temperature is 87
If the temperature is too high, such as 5°C, the difference in strength will be as large as 5kgf/2.
また圧延終了温度が７５０°Ｃ以下になれば中心部の強
度が低下することがわかり、板厚方向に均一な強度を得
るためには圧延終了温度を７５０〜８５０℃以内に限定
する必要があることがわかる。It was also found that the strength at the center decreases when the rolling end temperature is below 750°C, and in order to obtain uniform strength in the thickness direction, it is necessary to limit the rolling end temperature to within 750 to 850°C. I understand that.
実施例３
表５に成分を示す供試！ｉｔ （Ａ） 、 （Ｂ） 、
（Ｃ） 、 （Ｄ）を１０００°Ｃに加熱後、８７５
℃〜８１５℃のオーステナイト未再結晶域で７６％の加
工度を施し中心温度８１５℃で圧延を終了後、８１０℃
から冷却を開始し、中心部の冷却速度４℃／秒にて中心
温度４００°Ｃで冷却を終了し７５龍厚の厚鋼板を製造
した。得られた板厚中心部での機械的性質を表６に示す
。Example 3 Test sample whose components are shown in Table 5! it (A), (B),
After heating (C) and (D) to 1000°C, 875
After applying 76% working in the austenite non-recrystallized region between ℃ and 815℃ and finishing rolling at a center temperature of 815℃, the rolling process was completed at 810℃.
Cooling was started from , and cooling was completed at a center temperature of 400°C at a cooling rate of 4°C/sec to produce a thick steel plate with a thickness of 75 mm. Table 6 shows the mechanical properties at the center of the plate thickness obtained.
表５
表６
表６に示すようにＮｌの高い（Ａ）鋼について引張強度
５３ｋｇｆ／ｍｍ２、ｖＴｒｓ−９５℃、ｖＥ−６ｏ
１４．５ｋｇｆ−ｍとかなりすくれた値を示すが、Ｎ量
を２８ ｐｐｍにさげることによりｖＴｒｓ −１１０
°ｃ 、 ｖＥ−６ｏ：２０．５ｋｇｆ−ｍとじん性の
向上効果が著しい。さらに希土類元素添加の（Ｃ）鋼、
Ｚｒ添加の（Ｄ）鋼はそれぞれｖＴｒｓ−１２５°Ｃ，
ｖＥ−ａｏ：２４．３ｋｇｆ ＨｍおよびｖＴｒｓ −
１２３°Ｃ１ｖＥ−ｂｏ：２４．５ｋｇｆ−ｍと靭性の
向上が顕著になり、Ｒｅｍ及び／又はＺｒの添加による
しん性向上効果も明らかである。Table 5 Table 6 As shown in Table 6, the steel (A) with high Nl has a tensile strength of 53 kgf/mm2, vTrs-95℃, vE-6o
Although it shows a rather low value of 14.5 kgf-m, by reducing the amount of N to 28 ppm, vTrs -110
°c, vE-6o: 20.5 kgf-m, and the effect of improving toughness is remarkable. Furthermore, (C) steel with addition of rare earth elements,
Zr-added (D) steel is vTrs-125°C, respectively.
vE-ao: 24.3 kgf Hm and vTrs −
123°C1vE-bo: 24.5 kgf-m, the improvement in toughness is remarkable, and the effect of improving toughness due to the addition of Rem and/or Zr is also obvious.
（発明の効果）
この発明は工業的規模で安定に高張力高じん性鋼板を製
造することができ、加熱、圧延、冷却の管理ポイントは
かなりゆるやかな条件で与えられているため、大量生産
の場においても安定に目標とした鋼板の機械的性質を得
ることができる。(Effects of the invention) This invention can stably produce high-tensile, high-tension steel sheets on an industrial scale, and the control points of heating, rolling, and cooling are given under fairly loose conditions, making it possible to produce large-scale production. It is possible to stably obtain the targeted mechanical properties of the steel sheet even in the field.
Claims (1)
範囲に加熱後、未再結晶オーステナイト域で７０％以上
の加工度を施し、板厚中心部の温度が７５０〜８５０℃
の温度範囲にて熱間圧延を終了し、 板厚中心部で７５０℃以上の温度から、板厚中心部にお
ける１〜８℃／秒の冷却速度範囲で冷却を行い、板厚中
心部の温度が２００〜５００℃の温度範囲にて冷却を停
止する ことを特徴とする高張力高じん性鋼板の製造方法。 ２、炭素鋼又は低合金鋼が化学成分としてＡｌ：０．０
０５〜０．０８ｗｔ％、Ｎ：０．００５ｗｔ％以下を含
有するのものである、１記載の方法。 ３、炭素鋼又は低合金鋼が化学成分としてＡｌ：０．０
０５〜０．０８ｗｔ％、Ｎ：０．００５ｗｔ％以下を含
有しさらに全希土類元素：０．００３〜０．０３ｗｔ％
及び／又はＺｒ：０．００３〜０．０６ｗｔ％を含有す
るものである、１記載の方法。[Claims] 1. Carbon steel or low alloy steel is heated to a temperature range of 930 to 1060°C, and then processed to a degree of working of 70% or more in the unrecrystallized austenite region, so that the temperature at the center of the plate thickness is 750 to 1060°C. 850℃
The hot rolling is completed in the temperature range of 1. A method for producing a high tensile strength steel sheet, characterized in that cooling is stopped in a temperature range of 200 to 500°C. 2. Carbon steel or low alloy steel has Al as a chemical component: 0.0
05 to 0.08 wt%, N: 0.005 wt% or less, the method according to 1. 3. Carbon steel or low alloy steel has Al as a chemical component: 0.0
05 to 0.08 wt%, N: 0.005 wt% or less, and total rare earth elements: 0.003 to 0.03 wt%
and/or Zr: 0.003 to 0.06 wt%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28106985A JPS62139816A (en) | 1985-12-16 | 1985-12-16 | Manufacture of high tension and toughness steel plate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28106985A JPS62139816A (en) | 1985-12-16 | 1985-12-16 | Manufacture of high tension and toughness steel plate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62139816A true JPS62139816A (en) | 1987-06-23 |
| JPH0366367B2 JPH0366367B2 (en) | 1991-10-17 |
Family
ID=17633878
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28106985A Granted JPS62139816A (en) | 1985-12-16 | 1985-12-16 | Manufacture of high tension and toughness steel plate |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62139816A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100346307B1 (en) * | 1999-12-15 | 2002-07-26 | 두산중공업 주식회사 | A Low Alloy Steel added Al and N for High Tough Nuclear Reactor Pressure Vessel |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006118069A1 (en) | 2005-04-28 | 2006-11-09 | Eagle Industry Co., Ltd. | Mechanical seal device |
| WO2008013147A1 (en) | 2006-07-25 | 2008-01-31 | Eagle Industry Co., Ltd. | Mechanical seal device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59182915A (en) * | 1983-03-31 | 1984-10-17 | Sumitomo Metal Ind Ltd | Production of high tensile steel |
| JPS59190323A (en) * | 1983-04-12 | 1984-10-29 | Nippon Steel Corp | Production of low temperature steel |
| JPS6289815A (en) * | 1985-10-15 | 1987-04-24 | Kobe Steel Ltd | Manufacture of high yield point steel for low temperature |
-
1985
- 1985-12-16 JP JP28106985A patent/JPS62139816A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59182915A (en) * | 1983-03-31 | 1984-10-17 | Sumitomo Metal Ind Ltd | Production of high tensile steel |
| JPS59190323A (en) * | 1983-04-12 | 1984-10-29 | Nippon Steel Corp | Production of low temperature steel |
| JPS6289815A (en) * | 1985-10-15 | 1987-04-24 | Kobe Steel Ltd | Manufacture of high yield point steel for low temperature |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100346307B1 (en) * | 1999-12-15 | 2002-07-26 | 두산중공업 주식회사 | A Low Alloy Steel added Al and N for High Tough Nuclear Reactor Pressure Vessel |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0366367B2 (en) | 1991-10-17 |
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