JPH0432513A - Production of high tensile strength heat treated steel plate having low yield ratio and excellent in welding performance characteristics and discrimination characteristic - Google Patents
Production of high tensile strength heat treated steel plate having low yield ratio and excellent in welding performance characteristics and discrimination characteristicInfo
- Publication number
- JPH0432513A JPH0432513A JP13719790A JP13719790A JPH0432513A JP H0432513 A JPH0432513 A JP H0432513A JP 13719790 A JP13719790 A JP 13719790A JP 13719790 A JP13719790 A JP 13719790A JP H0432513 A JPH0432513 A JP H0432513A
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- Prior art keywords
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- point
- temperature
- cooling
- cooling velocity
- 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.)
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 41
- 239000010959 steel Substances 0.000 title claims abstract description 41
- 238000003466 welding Methods 0.000 title claims abstract description 19
- 238000004519 manufacturing process Methods 0.000 title claims description 15
- 238000001816 cooling Methods 0.000 claims abstract description 38
- 238000005098 hot rolling Methods 0.000 claims abstract description 9
- 238000005496 tempering Methods 0.000 claims abstract description 9
- 238000010438 heat treatment Methods 0.000 claims abstract description 6
- 238000003303 reheating Methods 0.000 claims abstract description 5
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 3
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 3
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 3
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 3
- 229910052802 copper Inorganic materials 0.000 claims abstract 2
- 229910052748 manganese Inorganic materials 0.000 claims abstract 2
- 239000000203 mixture Substances 0.000 abstract description 5
- 229910052759 nickel Inorganic materials 0.000 abstract description 3
- 229910052799 carbon Inorganic materials 0.000 abstract description 2
- 229910052804 chromium Inorganic materials 0.000 abstract description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 abstract 2
- 229910052761 rare earth metal Inorganic materials 0.000 abstract 1
- 150000002910 rare earth metals Chemical class 0.000 abstract 1
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 238000005096 rolling process Methods 0.000 description 17
- 238000005336 cracking Methods 0.000 description 8
- 239000004566 building material Substances 0.000 description 7
- 230000005764 inhibitory process Effects 0.000 description 7
- 239000010953 base metal Substances 0.000 description 6
- 230000007547 defect Effects 0.000 description 6
- 238000001514 detection method Methods 0.000 description 5
- 238000005520 cutting process Methods 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229910001563 bainite Inorganic materials 0.000 description 2
- 230000003749 cleanliness Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000004881 precipitation hardening Methods 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- -1 REM sulfides Chemical class 0.000 description 1
- 229910000746 Structural steel Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000000988 reflection electron microscopy Methods 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 150000003568 thioethers Chemical class 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
この発明は、特に建材のような用途に使って好適な、溶
接の施工性及び判別性に優れ、耐震設計に適合する６０
ｋｇｆ／ｍｍ２以上の高張力調質鋼板の製造方法に関す
るものである。Detailed Description of the Invention (Industrial Field of Application) This invention is particularly suitable for applications such as building materials, has excellent welding workability and distinguishability, and is suitable for earthquake-resistant design.
The present invention relates to a method for manufacturing a high tensile strength tempered steel plate of kgf/mm2 or more.
建材用の鋼板は、建築構造物の大型化、安全性の確保な
とから高張力化、厚肉化か要求され、さらには耐震設計
に適合し得る低降伏比を有する鋼が要求されている。Steel plates for building materials are required to have higher tensile strength and thicker walls due to the increasing size of building structures and ensuring safety, and there is also a need for steel with a low yield ratio that can be compatible with seismic design. .
そして、この建材に用いる高張力鋼板は、Ｈ形鋼や角柱
を製作する場合なと、溶接して使用される場合か多い。The high-strength steel plates used for building materials are often welded to produce H-beams and square columns.
この溶接を行なう場合、６０ｋｇｆ／ｍｍ２以上の高張
力鋼では、通常合金元素を含めて硬化成分を高目に含有
している二とから、溶接部の割れ欠陥防止のために、鋼
板の予熱の実施とこのための管理が必要となり施行上大
きな負荷となっている。また、溶接後において、溶接継
手部の欠陥の有無を判別する超音波探傷を実施している
か、この際、鋼板内部に結晶方位か一方向に揃った集合
組織かあると、超音波か減衰または曲げられるなどによ
り音響異方性か生じるため、超音波か探傷すべき溶接継
手対象部に届かず、欠陥の有無を正しく判別できなくな
る。When performing this welding, high-strength steel of 60 kgf/mm2 or higher usually contains high hardening components including alloying elements, so it is necessary to preheat the steel plate to prevent cracking defects in the weld. Implementation and management for this purpose are required, creating a heavy burden on enforcement. In addition, after welding, do you carry out ultrasonic flaw detection to determine the presence or absence of defects in the welded joint? At this time, if there is a crystal orientation or texture aligned in one direction inside the steel plate, ultrasonic waves may be attenuated or Because acoustic anisotropy occurs due to bending, etc., the ultrasonic waves do not reach the target part of the welded joint to be detected, making it impossible to correctly determine the presence or absence of defects.
したかって、建材用の高張力鋼板は、耐震設計に適合し
得る低降伏比を有し、溶接の施工にあたっては、予熱か
不要あるいは予熱温度を低減することかできるというこ
とによる溶接の施工性に優れるものとし、溶接施工後に
おける超音波探傷による溶接継手部の欠陥発見のしやす
さを、溶接の判別性ということにして、この溶接の判別
性に優れるものとすることか要望されている。Therefore, high-strength steel plates for building materials have a low yield ratio that is compatible with seismic design, and when performing welding, preheating is unnecessary or the preheating temperature can be reduced, which improves welding workability. The ease with which defects can be found in welded joints by ultrasonic flaw detection after welding is considered to be the distinguishability of welds, and it is desired that welds be excellent in distinguishability.
（従来の技術）
高張力鋼板について、調質処理により製造するものとし
て、特公昭５７−４０２０７号公報に溶接性か優れ引張
り強さか６０ｋｇｆ／ｍｍ２以上の高張力鋼の製造方法
か開示されている。しかしなからこの方法は、溶接性に
対しては、Ｃｅｑを規定することによって配慮している
ものの、建材の用途に必要とされる低降伏比については
触れられていない。(Prior art) Regarding high tensile strength steel plates, Japanese Patent Publication No. 1983-40207 discloses a method for producing high tensile strength steels with excellent weldability and tensile strength of 60 kgf/mm2 or more. . However, although this method takes weldability into consideration by specifying Ceq, it does not mention the low yield ratio required for use as a building material.
また、音響異方性の少ない低降伏比非調質鋼の製造方法
か特開平１−３０１８１９号公報に開示されており、圧
延仕上げ温度をＡ、３点＋１００ ’ＣからＡ ＋ ３
点の温度範囲として集合組織の生成を抑制する二とによ
り音響異方性を少なくしているか、調質鋼においては、
圧延仕上げ温度か上記温度範囲では低すぎて、音響異方
性は少なくならない。In addition, a method for manufacturing non-tempered steel with a low yield ratio and low acoustic anisotropy is disclosed in JP-A-1-301819, in which the rolling finishing temperature is set to A, and the temperature is changed from 3 points +100'C to A + 3 points.
In tempered steel, acoustic anisotropy is reduced by suppressing the formation of texture as the temperature range of the point changes.
The finishing temperature of rolling is too low in the above temperature range, and the acoustic anisotropy does not decrease.
（発明か解決しようとする課題）
この発明は、前記した建材に用いる鋼板に要求される特
性、すなわち、高張力で、調質鋼であるにもかかわらず
低降伏比を有し、予熱不要あるいは予熱温度低減を可能
とすることにより溶接の施工性か優れるものとし、超音
波探傷に支障のない程度に音響異方性か少ないことによ
り溶接の判別性か優れる、などの性質を有する鋼板の製
造方法であって、たとえ板厚か厚くとも製造容易な製造
方法を提供しようとするものである。(Problems to be Solved by the Invention) This invention has the characteristics required of the steel plate used for building materials as described above, namely, high tensile strength, low yield ratio despite being tempered steel, no preheating required, and Manufacture of steel sheets that have properties such as superior welding workability by making it possible to reduce the preheating temperature, and superior welding discrimination by having low acoustic anisotropy to the extent that it does not interfere with ultrasonic flaw detection. The purpose is to provide a manufacturing method that is easy to manufacture even if the plate is thick.
（課題を解決するための手段）
この発明の要旨は、Ｃ： ０．０３ｗｔ％以上、０．１
２ｗｔ９４５以下、Ｓｉ ： ０．６０ｗｔ！％以下、
Ｍｎ ： ２．０ｗｔ％以下、Ａ ｌ ： ０．００１
ｗｔ９６以上、０．１ｗｔ％以下、及びＮ・０．００
６ ｗｔ％以下、を含み、さらに、Ｃｒ ： １．０ｗ
ｔ％以下、Ｎｉ ： １．０ｗｔ！％以下、Ｍ。(Means for Solving the Problems) The gist of this invention is that C: 0.03 wt% or more, 0.1
2wt945 or less, Si: 0.60wt! %below,
Mn: 2.0wt% or less, Al: 0.001
wt96 or more, 0.1wt% or less, and N・0.00
6 wt% or less, and further includes Cr: 1.0w
Less than t%, Ni: 1.0wt! % or less, M.
１．０ｗｔ９４５以下、Ｖ ： ０．１ ｗｔ％以下、
Ｔｉ ： ０． ｌ ｗｔ９６以下、Ｎｂ ： ０．
］ ｗｔ９６以下、Ｂ ： ０．００５ ｗｔ％以下、
Ｃｕ ： １．０ｗｔ９４以下、及びＲＥＭ ： Ｏ，
Ｉ ｗｔ９６以下、のうちちから選んた１種又は２種以
上を含有し、かて計算されるＰ ｃＭ（ｗｔ％）か０．
２２Ｗｔ ％以下の鋼スラブを素材として、熱間圧延を
行い、Ａ、点十１００°Ｃ超えの温度て熱間圧延を終了
し、ひきつってＡ ｔ ３点以上の温度より空冷以上の
冷却速度で冷却するか、又は、Ａ ｃ ３点以上の温度
に再加熱後、空冷の冷却速度以上の速度で冷却し、さら
にＡ Ｃ１点からＡ ｃ ＋点の２相域温度範囲に加熱
保持した後、空冷の冷却速度以上の速度で冷却し、その
後人。1.0wt945 or less, V: 0.1wt% or less,
Ti: 0. l wt96 or less, Nb: 0.
] wt96 or less, B: 0.005 wt% or less,
Cu: 1.0wt94 or less, and REM: O,
Contains one or more selected from I wt 96 or less, and P cM (wt%) previously calculated or 0.
A steel slab of 22 Wt % or less is used as a raw material, hot rolled, and the hot rolling is finished at a temperature exceeding 100°C at point A, and then at a cooling rate of air cooling or higher from a temperature of 3 or more points A. After cooling or reheating to a temperature of A c 3 points or more, cooling at a rate higher than the cooling rate of air cooling, and further heating and holding in a two-phase temperature range from A C1 point to A c + point, Cool at a rate higher than the cooling rate of air cooling, and then use a person.
意思下の温度域で焼戻し処理を行うことを特徴とする溶
接の施工性及び判別性に優れる低降伏比高張力調質鋼板
の製造方法である。This is a method for producing a low yield ratio, high tensile strength tempered steel sheet with excellent welding workability and distinguishability, which is characterized by performing tempering treatment in a desired temperature range.
ここに、不純物として含有するＰ、 Ｓは、母材、溶
接部の靭性に悪影響をおよぼすものであることから、Ｐ
は０．０３０ ｗｔ％以下、Ｓは０．０１０ ｗｔ％以
下、また、溶接割れに大きく影響するＨは０．０００２
ｗｔ％以下とすることか好ましい。Here, P and S contained as impurities have a negative effect on the toughness of the base metal and the weld zone, so P and S are contained as impurities.
is 0.030 wt% or less, S is 0.010 wt% or less, and H, which greatly affects weld cracking, is 0.0002
It is preferable that it be less than wt%.
ＰＣＭは溶接割れ感受性指数と呼ぶもので、溶接割れに
およぼす化学成分の影響を評価するために用いる値であ
る。PCM is called a weld cracking susceptibility index, and is a value used to evaluate the influence of chemical components on weld cracking.
Ａ、＋１００’Ｃ超えの温度で熱間圧延を終了するとい
うことは、熱間圧延における仕上げ温度をＡ、＋１００
°Ｃ超えの温度とすることの意味で、この仕上げ温度に
より音響異方性を生ずる集合組織の生成を抑制する。Finishing hot rolling at a temperature exceeding A, +100'C means that the finishing temperature in hot rolling is A, +100'C.
This finishing temperature, in the sense of a temperature in excess of 0.degree. C., suppresses the formation of textures that cause acoustic anisotropy.
その後、Ａ Ｃ３点以上の温度からの冷却は、熱間圧延
に連続して行ってもよく、また、−度冷却した後再加熱
して行ってもよく、これを行なうことにより組織の均一
化、微細化を計るものである。After that, cooling from a temperature of A C3 or above may be performed continuously during hot rolling, or may be performed by cooling by -degrees and then reheating, and by doing this, the structure can be made uniform. , which measures miniaturization.
次にＡ ｅ ３点からＡｃ１点の２相域温度範囲に加熱
保持し、冷却することは、フェライトとマルテシサイト
又はベイナイトの混合組織とするだめのものであり、そ
の後のＡｅ１点以下の焼戻しは、上記組織を焼戻しする
ことにより靭性か向上し、かくすることにより目的とす
る性質の鋼板か得られるものである。Next, heating and holding in the two-phase temperature range from Ae 3 points to Ac 1 point and cooling is not necessary to create a mixed structure of ferrite and martesisite or bainite, and subsequent tempering to below Ae 1 point. The toughness is improved by tempering the above-mentioned structure, thereby obtaining a steel plate with the desired properties.
（作 用）
まずこの発明の鋼組成における化学成分範囲の限定理由
について述へる。(Function) First, the reason for limiting the range of chemical components in the steel composition of this invention will be described.
Ｃ：母材の強度保証上０．０３ｗｔ％以上か必要である
か、溶接割れ感受性指数Ｐ。Ｍの計算式から明らかなよ
うに、大きく溶接割れに影響する元素であることから、
０．１２ｗｔ％を上限とする。C: Weld cracking susceptibility index P, whether 0.03 wt% or more is necessary to guarantee the strength of the base metal. As is clear from the formula for M, since it is an element that greatly affects weld cracking,
The upper limit is 0.12 wt%.
Ｓｊ： 脱酸に用いられ、０．１０ｗｔ％以上含有す
ることか好ましいか、母材の溶接熱影響部（単にＨＡＺ
という）の靭性、および溶接性を劣化させるため０．６
ｗｔ％を上限とする。Sj: Used for deoxidation, preferably containing 0.10 wt% or more, weld heat affected zone (simply HAZ) of the base metal.
0.6 because it deteriorates the toughness and weldability of
The upper limit is wt%.
Ｍｎ 強度および靭性を同時に向上させる極めて重
要な成分て０．６ｗｔ％以上含有することか好ましいか
、多量に添加すると溶接性とＨＡＺの靭性を劣化させる
ため、２．０ｗｔ％を上限とする。Mn is an extremely important component that improves strength and toughness at the same time, so it is preferable to contain 0.6 wt% or more, but since adding a large amount deteriorates weldability and HAZ toughness, the upper limit is set at 2.0 wt%.
ＡＡ 脱酸に用いられ、０．００１ ｗｔＮ未満ては
脱酸か不十分になり、０．１ｗｔ％を超えると鋼の清浄
度およびＨＡＺの靭性か劣化するため、下限を０．００
１ｗｔ％、上限を０．１ｗｔ％とする。AA is used for deoxidation, and if it is less than 0.001 wtN, deoxidation will be insufficient, and if it exceeds 0.1 wt%, the cleanliness of the steel and the toughness of the HAZ will deteriorate, so the lower limit is set to 0.00
1 wt%, and the upper limit is 0.1 wt%.
Ｎ 溶鋼中に不可避的に浸入し鋼の靭性を劣化させるた
め、０．００６ ｗｔ％以下に抑制する。Since N inevitably enters molten steel and deteriorates the toughness of the steel, it is suppressed to 0.006 wt% or less.
さらに、この発明においては、上記に規定した成分に加
え、Ｃｒ、 Ｎｉ、 Ｍｏ、 Ｖ、 Ｔｉ、 Ｎｂ、
Ｂ、 Ｃｕ。Furthermore, in this invention, in addition to the components specified above, Cr, Ni, Mo, V, Ti, Nb,
B.Cu.
ＲＥＭのうちから選んだ１種又は２種以上を含有させる
。Contain one or more selected REMs.
これらの成分を含有させる主たる目的は、強度および靭
性の向上と製造可能な板厚範囲の拡大とにあり、それぞ
れの添加量は溶接性やＨＡＺての靭性を阻害しない範囲
とする。The main purpose of containing these components is to improve strength and toughness and to expand the range of plate thickness that can be manufactured, and the amount of each added is within a range that does not impede weldability or HAZ toughness.
すなわち、これらについては以下の通りである。That is, these are as follows.
Ｃｒ： 母材の強度を高めるほか耐水素誘起割れ性に
対しても有効であるか、１．０ｗｔ９ｔｉを超えるとＨ
ＡＺの硬化性を増大して靭性及び溶接性を低下させるた
め、上限を１．０ｗｔ９６とする。Cr: In addition to increasing the strength of the base metal, it is also effective against hydrogen-induced cracking.
In order to increase the hardenability of AZ and reduce toughness and weldability, the upper limit is set to 1.0wt96.
Ｎ１．適当量において、１（Ａ２の硬化性及び靭性に悪
影響を及はすことな・（、母材の強度及び靭性を向上さ
せるか、１．０ｗｔ９６を超えるとＨＡｌの硬化性及び
靭性を阻害するため、上限を１．０ｗｔ０ｔｉとする。N1. In an appropriate amount, 1 (does not adversely affect the hardenability and toughness of A2), improves the strength and toughness of the base material, or inhibits the hardenability and toughness of HAl if it exceeds 1.0wt96. , the upper limit is 1.0wt0ti.
ＭＯ： 母材の強度及び靭性を向上させる成分である
か、１．０ｗｔ％を超えると溶接部の靭性及び溶接性の
劣化をまねくため、上限を１．０ｗｔ９４５とする。MO: This is a component that improves the strength and toughness of the base metal.If it exceeds 1.0wt%, it causes deterioration of the toughness and weldability of the welded part, so the upper limit is set to 1.0wt945.
Ｖ：析出硬化に有効であるか、０．１ｗｔ％を超えると
溶接性の劣化をまねくため、上限を０．１ｗｔ９ｆ５と
する。V: Is it effective for precipitation hardening? If it exceeds 0.1wt%, weldability deteriorates, so the upper limit is set to 0.1wt9f5.
Ｔ１．オーステナイト粒の細粒化に有効であるか、０．
１ｗｔ％を超えると溶接性の劣化をまねくため、上限を
０．１ｗｔ％とする。T1. Is it effective for refining austenite grains?
If it exceeds 1 wt%, weldability deteriorates, so the upper limit is set to 0.1 wt%.
Ｎｂ： 析出硬化に有効であるか、０．１ｗｔ％を超
えると靭性の劣化をまねくため、上限を０．］ｗｔ％と
する。Nb: Is it effective for precipitation hardening, but if it exceeds 0.1 wt%, the toughness deteriorates, so the upper limit is set to 0. ]wt%.
Ｂ 高強度化に有効であるか、０．ＯＱ５ ｗｔ９４５
を超えるとＨＡＺの靭性を著しく劣化するため、上限を
０．００５ ｗｔ％とする。B Is it effective for increasing strength? 0. OQ5 wt945
Since the toughness of the HAZ will be significantly deteriorated if the content exceeds 0.005 wt%.
Ｃｕ 強度、靭性の向上に加え、耐食性および耐水
素誘起割れ性に対しても有効であるか、１．０ｗｔ％を
超えると圧延中にクラックか発生し製造か困難になるた
め、上限を１．０ｗｔ９６とする。In addition to improving strength and toughness, Cu is also effective for corrosion resistance and hydrogen-induced cracking resistance.If it exceeds 1.0 wt%, cracks will occur during rolling, making manufacturing difficult, so the upper limit is set to 1.0 wt%. It is set to 0wt96.
ＲＥＶ ： ＭｎＳを球状化してシャルピー吸収エネル
キーを上昇させるほか、圧延によって延伸化したＭｎＳ
及び水素による内部欠陥の発生を防止する。REV: In addition to spheroidizing MnS to increase the Charpy absorption energy key, MnS stretched by rolling
and prevent the occurrence of internal defects due to hydrogen.
しかし０．０１ ｗｔ％を超えると、ＲＥＭの硫化物や
硫酸化物か大量に生成して大型介在物となり、鋼の清浄
度を劣下させ母材の靭性及び溶接性を劣化させる。した
かって、上限を０．０１ｗｔ％とする。However, if it exceeds 0.01 wt%, a large amount of REM sulfides and sulfides will be generated and become large inclusions, which will deteriorate the cleanliness of the steel and the toughness and weldability of the base metal. Therefore, the upper limit is set to 0.01 wt%.
さらに、この発明では上記した成分範囲と共に、Ｐ ｃ
Ｍ： ０．２２ｗｔ％以下を満足させる必要がある。Furthermore, in this invention, in addition to the above-mentioned component range, P c
M: It is necessary to satisfy 0.22 wt% or less.
すなわち
Ｐ ｃＭ（Ｗｊ％）−Ｃ（ｗｔ％戸 Ｓｉ（ｗｔ％
）２０ ２ｆＪ
ｂす（ｗｔ％）で表わされる溶接割れ感受性
指数は、溶接割れ阻止温度（予熱温度）と良い相関があ
る。第１図は、ｐ ｃ＋＋＋値と斜めＹ彫刻れ試験（Ｊ
ＩＳ Ｚ ３１５８）による溶接割れ阻止温度（予熱温
度）の関係を、日本溶接協会溶接構造用鋼規格ＨＷ５０
、ＨＷ７０鋼の板厚１６ｍｍから５０ ｍｍの鋼板に
ついてプロットしたものであるか、この図から明らかな
ように、溶接割れ阻止温度を５０°Ｃ以下とするために
はＰ。Ｍは０、２２ｗｔ％以下であることか必要である
。なお、溶接割れ阻止温度を５０°Ｃ以下とした理由は
、５０ｋｇｆ／ｍｍ２鋼なみの溶接性を目途に設定した
値である。That is, P cM (Wj%) - C (wt%) Si (wt%
)20 2fJ
The weld crack susceptibility index expressed in bsu (wt%) has a good correlation with the weld crack inhibition temperature (preheating temperature). Figure 1 shows the p c+++ value and diagonal Y engraving test (J
The relationship between weld crack inhibition temperature (preheating temperature) according to IS Z 3158) is based on the Japan Welding Association Welding Structural Steel Standard HW50.
, is plotted for HW70 steel plates with thicknesses from 16 mm to 50 mm.As is clear from this figure, in order to keep the weld crack inhibition temperature below 50°C, P is required. It is necessary that M be 0.22 wt% or less. The reason why the weld crack prevention temperature is set to 50°C or lower is that the weldability is set to be equivalent to that of 50 kgf/mm2 steel.
つぎに、熱間圧延、調質条件について述へる。Next, hot rolling and tempering conditions will be described.
この発明の化学成分を有する鋼スラブを熱間圧延するに
あたり、圧延仕上げ温度をＡ、３＋１００°Ｃ超えると
することか必要である。これは、Ａ、３＋１００°Ｃ超
えにて圧延を終了することによって、未再結晶域での圧
下を極力防止して集合組織の生成を抑制し、音響異方性
の発生を回避することにある。第２図は横軸に圧延仕上
げ温度、縦軸に音速比をとり、圧延仕上げ度と音響異方
性の関係を示したもので、圧延仕上げ温度か高（なるに
従い音速比は１．００に近すき音響異方性は少なくなる
。When hot rolling a steel slab having the chemical composition of the present invention, it is necessary to set the rolling finishing temperature to exceed A, 3+100°C. A. By finishing rolling at a temperature exceeding 3 + 100°C, rolling is prevented as much as possible in the unrecrystallized area, suppressing the formation of texture, and avoiding the occurrence of acoustic anisotropy. . Figure 2 shows the relationship between rolling finish and acoustic anisotropy, with the horizontal axis representing rolling finish temperature and the vertical axis representing sound speed ratio. Near-field acoustic anisotropy is reduced.
そして、音速比１．０２以下を満足させるためには、圧
延仕上げ温度はＡ 、 ３ ＋ １００’Ｃ超えとする
ことか必要になる。ここで音速比は探触子の振動方向を
Ｌ方向（圧延方向と平行）、及びＣ方向（圧延方向と直
角）にそれぞれ揃え、得られた音速値の比（Ｌ方向の音
速／Ｃ方向の音速）を小数点２桁まで求め音速比とした
ものである。また、音速比を１．０２以下とした理由は
、この値を超える場合は、超音波探傷による溶接継手部
の評価か正しくてきなくなるためである。In order to satisfy the sound speed ratio of 1.02 or less, the rolling finishing temperature must exceed A,3+100'C. Here, the sound speed ratio is calculated by aligning the vibration direction of the probe in the L direction (parallel to the rolling direction) and the C direction (perpendicular to the rolling direction), and the obtained sound speed value ratio (Sound speed in the L direction/C direction). The speed of sound) is calculated to two decimal places and used as the sound speed ratio. The reason why the sound velocity ratio is set to 1.02 or less is that if it exceeds this value, the evaluation of the welded joint by ultrasonic flaw detection will not be accurate.
つぎに、圧延後、又はＡ。３点以上の温度に再加熱後に
空冷以上の速度で冷却し、ついて、Ａ Ｃ３点からＡ。Next, after rolling or A. After reheating to a temperature of 3 points or more, cooling at a speed higher than air cooling, from A to A.
１点の温度範囲に加熱した後再度空冷以上の冷却速度で
冷却した後、さらにＡ。１点以下の温度で焼戻し処理を
施すことを必要とするか、まず、圧延に続いて、又は圧
延後−度冷却し、その後人。３点以上の温度に加熱し、
ＡＣ３点以上の温度から空冷以上の速度で冷却すること
は、鋼板の緒特性に好影響をおよほす組織の均一化、微
細化のためてあり、
ついて、Ａｏ３点からＡ。１点の２相域温度範囲に加熱
した後、空冷以上の冷却速度で冷却することは、低降伏
比、高張力、靭性なとを得るのに好適な組織、すなわち
フェライトとマルテンサイト又はベイナイトの混合組織
とするためてあり、その後のＡＣ１点以下の温度での焼
戻しは、上記組織を焼戻し組織とすることにより靭性の
向上を計るためのものである。After heating to a temperature range of one point and cooling again at a cooling rate higher than air cooling, further A. It is necessary to carry out a tempering treatment at a temperature below 1 point, first followed by rolling, or after rolling - degree cooling and then human. Heat to a temperature of 3 or more points,
Cooling at a speed higher than air cooling from a temperature of AC3 or higher is to make the structure uniform and finer, which has a positive effect on the properties of the steel sheet. After heating to a two-phase temperature range at one point, cooling at a cooling rate higher than air cooling produces a structure suitable for obtaining low yield ratio, high tensile strength, and toughness, that is, ferrite and martensite or bainite. A mixed structure is formed, and the subsequent tempering at a temperature below the AC1 point is intended to improve toughness by converting the above structure into a tempered structure.
（実施例）
転炉て溶製し、連鋳て鋳造した表１に示す成分組成の鋼
スラブを、表２に示す製造条件によって鋼板とし、これ
らの鋼板について、機械的特性、溶接施工性として斜め
Ｙ彫刻れ試験による溶接割れ阻止温度、音響異方性（音
速比）なとの測定を行なった。この結果を表３及び表４
に示す。(Example) Steel slabs with the composition shown in Table 1, which were melted in a converter and cast by continuous casting, were made into steel plates under the manufacturing conditions shown in Table 2, and the mechanical properties and weldability of these steel plates were evaluated. The weld crack inhibition temperature and acoustic anisotropy (sound velocity ratio) were measured using a diagonal Y engraving test. These results are shown in Tables 3 and 4.
Shown below.
々
４」
ユニに機械的特性は、ＪＩＳ ２２２４１．２２４２に
準拠したものであり、斜めＹ形削れ試験は、ＪＩＳ Ｚ
３１５８によるものである。The mechanical properties of the unit are based on JIS 22241.2242, and the diagonal Y-shape cutting test is based on JIS Z
3158.
表３は、基本成分に加え９種類の添加元素を各１種類、
２種類、及び３種類含有する表１に示す鋼記号ＡからＫ
まての計１１種類の鋼を用いて、表２に示す製造条件番
号３によって製造したこの発明の適合例を示すものであ
り、表４は表１に示すＬからＰ ２まで７種類の鋼を
用いて表２に示す全ての製造条件で製造した、この発明
の適合例及び比較例を示すものである。Table 3 shows that in addition to the basic ingredients, one type of each of the nine types of additive elements,
Steel symbols A to K shown in Table 1 containing 2 types and 3 types
This shows an example of conformity to the present invention manufactured using a total of 11 types of steel according to manufacturing condition No. 3 shown in Table 2. This figure shows a conforming example and a comparative example of the present invention, which were manufactured under all the manufacturing conditions shown in Table 2.
表４より、２６Ｍ値が０．２２ｗｔ％を超えている０−
２、Ｐ−２鋼を用いた比較例は、斜めＹ形削れ試験にお
ける溶接割れ阻止温度は７５°Ｃから１００°Ｃと高く
、また、圧延仕上げ温度がＡ ｒ ３点よりは高いかＡ
ｒ ３点＋１００ ’Ｃより低い製造条件番号２，４
の比較例は音速比は１．０３から１．０６と大きくなっ
ており、溶接の施工性、判別性ともに劣ることを示して
いる。From Table 4, 0- with a 26M value exceeding 0.22wt%
2. In the comparative example using P-2 steel, the welding crack inhibition temperature in the diagonal Y-shape cutting test was as high as 75°C to 100°C, and the rolling finishing temperature was higher than A r 3 points.
Manufacturing condition number 2, 4 lower than r 3 points + 100'C
In the comparative example, the sound speed ratio is large from 1.03 to 1.06, indicating that both welding workability and distinguishability are inferior.
以上に対し、表３、及び表４に示すこの発明の適合例は
、斜めＹ形削れ試験における溶接割れ阻止温度は２５°
Ｃ以下、音速比は０．９９から１．０１と優れており、
溶接の施工性、及び判別性ともに優れることを示してい
る。In contrast to the above, the conforming examples of the present invention shown in Tables 3 and 4 have a weld crack inhibition temperature of 25° in the diagonal Y-shape cutting test.
Below C, the sound speed ratio is excellent at 0.99 to 1.01,
This shows that both welding workability and distinguishability are excellent.
そして、引張強さは全て６０ｋｇｆ／ｍｍ２以上を示し
ており、降伏比は調質鋼であるにもかかわらず７０９６
から７９９６と低い値を示している。And, the tensile strength is all 60kgf/mm2 or more, and the yield ratio is 7096 even though it is tempered steel.
It shows a low value of 7996.
（発明の効果）
この発明は、６０ｋｇｆ／ｍｍ２以上の高張力を有し、
従来鋼に比較して、溶接施工能率か向上でき、超音波探
傷による溶接欠陥の検出を確実に行なうことかてき、か
つ調質鋼であるにもかかわらす低降伏比を有する建材に
用いて好適な鋼板を、製造可能としたものである。(Effect of the invention) This invention has a high tension of 60 kgf/mm2 or more,
Compared to conventional steel, welding efficiency can be improved, welding defects can be reliably detected by ultrasonic flaw detection, and although it is tempered steel, it is suitable for use in building materials with a low yield ratio. This makes it possible to manufacture steel plates with
第１図は、ＰＣＭ値と斜めＹ形削れ試験による溶接割れ
阻止温度との関係を示すグラフ、及び第２図は圧延仕上
温度と音響異方性の関係を示すグラフである。
ＰＣ間（ｗｔＺ＞
７００ ８００ ＱＯＯ
イｋｋ（”ｔ”、’ｘ１／８Ｆ（’＋ｊｆブ００FIG. 1 is a graph showing the relationship between the PCM value and the weld crack inhibition temperature determined by the diagonal Y-shape cutting test, and FIG. 2 is a graph showing the relationship between the finishing rolling temperature and acoustic anisotropy. Between PCs (wtZ> 700 800 QOO Ikk("t",'x1/8F('+jfb00
Claims (1)
ｉ：０．６０ｗｔ％以下、 Ｍｎ：２．０ｗｔ％以下、 Ａｌ：０．００１ｗｔ％以上、０．１ｗｔ％以下、及び
Ｎ：０．００６ｗｔ％以下、 を含み、さらに、 Ｃｒ：１．０ｗｔ％以下、 Ｎｉ：１．０ｗｔ％以下、 Ｍｏ：１．０ｗｔ％以下、 Ｖ：０．１ｗｔ％以下、 Ｔｉ：０．１ｗｔ％以下、 Ｎｂ：０．１ｗｔ％以下、 Ｂ：０．００５ｗｔ％以下、 Ｃｕ：１．０ｗｔ％以下、及び ＲＥＭ：０．１ｗｔ％以下、 のうちから選んだ１種又は２種以上を含有し、かつ、 Ｐ＿Ｃ＿Ｍ（ｗｔ％）＝Ｃ（ｗｔ％）＋［１／３０］Ｓ
ｉ（ｗｔ％）＋［１／２０］Ｍｎ（ｗｔ％）＋［１／２
０］Ｃｒ（ｗｔ％）＋［１／６０］Ｎｉ（ｗｔ％）＋［
１／１５］Ｍｏ（ｗｔ％）＋［１／１０］Ｖ（ｗｔ％）
＋５Ｂ（ｗｔ％）＋［１／２０］Ｃｕ（ｗｔ％）で計算
されるＰ＿Ｃ＿Ｍ（ｗｔ％）が０．２２ｗｔ％以下の鋼
スラブを素材として、熱間圧延を行い、Ａ＿ｒ＿３点＋
１００℃超えの温度で熱間圧延を終了し、ひきつづてＡ
＿ｒ＿３点以上の温度より空冷以上の冷却速度で冷却す
るか、又はＡ＿Ｃ＿３点以上の温度に再加熱後、空冷の
冷却速度以上の速度で冷却し、さらにＡ＿Ｃ＿３点から
Ａ＿Ｃ＿１点の２相域温度範囲に加熱保持した後、空冷
の冷却速度以上の速度で冷却し、その後Ａ＿Ｃ＿１点以
下の温度域で焼戻し処理を行うことを特徴とする溶接の
施工性及び判別性に優れる低降伏比高張力調質鋼板の製
造方法。[Claims] 1. C: 0.03 wt% or more, 0.12 wt% or less, S
i: 0.60 wt% or less, Mn: 2.0 wt% or less, Al: 0.001 wt% or more, 0.1 wt% or less, and N: 0.006 wt% or less, furthermore, Cr: 1.0 wt%. Below, Ni: 1.0 wt% or less, Mo: 1.0 wt% or less, V: 0.1 wt% or less, Ti: 0.1 wt% or less, Nb: 0.1 wt% or less, B: 0.005 wt% or less, Cu: 1.0 wt% or less, REM: 0.1 wt% or less, and contains one or more selected from the following, and P_C_M (wt%) = C (wt%) + [1/30 ]S
i (wt%) + [1/20] Mn (wt%) + [1/2
0]Cr (wt%) + [1/60]Ni (wt%) + [
1/15]Mo (wt%) + [1/10]V (wt%)
+5B (wt%) + [1/20] A steel slab with P_C_M (wt%) calculated by Cu (wt%) of 0.22wt% or less was hot rolled, and A_r_3 points +
Hot rolling is finished at a temperature exceeding 100°C, and then A
Cooling at a cooling rate higher than that of air cooling from a temperature of _r_3 points or higher, or reheating to a temperature of A_C_3 points or higher, cooling at a rate higher than the cooling rate of air cooling, and then two-phase temperature range from point A_C_3 to point A_C_1. Low yield ratio, high tension tempering with excellent welding workability and distinguishability, characterized by heating and holding at a temperature, then cooling at a rate higher than the cooling rate of air cooling, and then tempering in a temperature range below A_C_1 point. Method of manufacturing steel plates.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13719790A JPH0432513A (en) | 1990-05-29 | 1990-05-29 | Production of high tensile strength heat treated steel plate having low yield ratio and excellent in welding performance characteristics and discrimination characteristic |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13719790A JPH0432513A (en) | 1990-05-29 | 1990-05-29 | Production of high tensile strength heat treated steel plate having low yield ratio and excellent in welding performance characteristics and discrimination characteristic |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0432513A true JPH0432513A (en) | 1992-02-04 |
Family
ID=15193065
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13719790A Pending JPH0432513A (en) | 1990-05-29 | 1990-05-29 | Production of high tensile strength heat treated steel plate having low yield ratio and excellent in welding performance characteristics and discrimination characteristic |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0432513A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04272129A (en) * | 1991-02-27 | 1992-09-28 | Nkk Corp | Production of high tension steel having low yield ratio |
| US9160121B2 (en) | 2011-03-08 | 2015-10-13 | Huber+Suhner Ag | High frequency coaxial connector |
-
1990
- 1990-05-29 JP JP13719790A patent/JPH0432513A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04272129A (en) * | 1991-02-27 | 1992-09-28 | Nkk Corp | Production of high tension steel having low yield ratio |
| US9160121B2 (en) | 2011-03-08 | 2015-10-13 | Huber+Suhner Ag | High frequency coaxial connector |
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