JPS62180013A - Manufacture of nontemper high tension steel plate having low welding crack susceptibility - Google Patents
Manufacture of nontemper high tension steel plate having low welding crack susceptibilityInfo
- Publication number
- JPS62180013A JPS62180013A JP2120186A JP2120186A JPS62180013A JP S62180013 A JPS62180013 A JP S62180013A JP 2120186 A JP2120186 A JP 2120186A JP 2120186 A JP2120186 A JP 2120186A JP S62180013 A JPS62180013 A JP S62180013A
- Authority
- JP
- Japan
- Prior art keywords
- less
- ceq
- steel
- temperature
- carbon equivalent
- 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.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 60
- 239000010959 steel Substances 0.000 title claims abstract description 60
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 238000003466 welding Methods 0.000 title description 15
- 238000005096 rolling process Methods 0.000 claims abstract description 23
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 19
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 10
- 239000012535 impurity Substances 0.000 claims abstract description 9
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 6
- 229910052802 copper Inorganic materials 0.000 claims abstract description 4
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 4
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 4
- 229910052759 nickel Inorganic materials 0.000 claims abstract 3
- 238000005336 cracking Methods 0.000 claims description 20
- 238000001816 cooling Methods 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 13
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 10
- 229910052742 iron Inorganic materials 0.000 claims description 5
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims 4
- 239000011574 phosphorus Substances 0.000 claims 4
- 238000010438 heat treatment Methods 0.000 abstract description 19
- 239000000463 material Substances 0.000 abstract description 9
- 229910052748 manganese Inorganic materials 0.000 abstract description 2
- 230000002542 deteriorative effect Effects 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 8
- 238000005204 segregation Methods 0.000 description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 239000010953 base metal Substances 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 2
- 230000001186 cumulative effect Effects 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000007670 refining Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 101100112225 Emericella nidulans (strain FGSC A4 / ATCC 38163 / CBS 112.46 / NRRL 194 / M139) cpa-1 gene Proteins 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013256 coordination polymer Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 210000002700 urine Anatomy 0.000 description 1
- 239000002966 varnish Substances 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】
く産業上の利用分野〉
この発明は溶歴割れ感受性の低い非調質高張力３１．１
板の人造方法に関し、大入熱溶接時に溶接部近傍に多発
する微細割れの発生を抑制することを目的とするもので
ある。[Detailed description of the invention] Industrial application field> This invention is a non-thermal high tensile strength 31.1
Regarding the artificial method of manufacturing plates, the purpose is to suppress the occurrence of microscopic cracks that frequently occur near the welded part during high heat input welding.
〈従来の技術〉
厚鋼板の用途として大きな比率を占めている造船用鋼板
について、従来より高張力化の要求があり、降伏点３２
キロ級５０キロ鋼板は広く普及している。<Conventional technology> For shipbuilding steel plates, which account for a large proportion of the applications of thick steel plates, there has been a demand for higher tensile strength, and the yield point is 32.
Kilo class 50 kg steel plates are widely used.
しかし、これ以上の例えば降伏点３６キロ級５０キロ鋼
板は、従来法で製造した場合には溶接性が劣化する間亀
があった・造船用鋼板はその使用過程で各種の溶接施工
をうけるため、溶接性の劣化は重大な問題となる。However, if a 50kg steel plate with a yield point of 36kg or more is produced using conventional methods, weldability may deteriorate due to the fact that shipbuilding steel plates undergo various welding processes during their use. , deterioration of weldability becomes a serious problem.
このような従来の問題点を解決したのが、近年に至って
大きな進歩を遂げた所謂新制御圧延法と呼ばれる制御圧
延、制御冷却技術であり、これにより、高靭性、高溶接
性の非調質型高張力鋼板の製造が可能となった。The solution to these conventional problems is the controlled rolling and controlled cooling technology known as the so-called new controlled rolling method, which has made great progress in recent years. It became possible to manufacture molded high-tensile steel plates.
たとえば、この技術を用いた降伏点３６キロ級５０キロ
鋼板は従来型の降伏点３２キロ級５０キロ鋼板と同等以
上の溶接性を有しており、今後急速に普及すると考えら
れている。For example, a 50kg steel plate with a yield point of 36kg using this technology has weldability equal to or better than a conventional 50kg steel plate with a yield point of 32kg, and is expected to become popular in the future.
この新制御圧延法の特長は従来の制御圧延法の延長にあ
って、スラブの低温加熱、低温域での圧延強化、低温仕
上り、圧延後の加速冷却等の組合せにより靭性改善と強
度上昇を図ることにあり、これに依って成分の低下と溶
接性の改善を達成している。The feature of this new controlled rolling method is that it is an extension of the conventional controlled rolling method, and aims to improve toughness and increase strength through a combination of low-temperature heating of the slab, rolling strengthening in the low-temperature range, low-temperature finishing, and accelerated cooling after rolling. In particular, this has resulted in a reduction in components and an improvement in weldability.
しかし、最近これら新制御圧延法で製造された鋼板に対
して造船で多用される大入熱溶接をおこなった場合溶接
線に沿って、鋼板の板厚中央に微細な割れを生じ易いツ
が指摘されており、実、験によっても現尿の再現が確認
されている。However, it has recently been pointed out that when high heat input welding, which is often used in shipbuilding, is performed on steel plates manufactured using these new controlled rolling methods, microscopic cracks tend to occur along the weld line at the center of the thickness of the steel plate. In fact, the reproduction of real urine has been confirmed through experiments.
この割れは溶接金属に近りした母材部分のほぼ板厚中央
に位置し、板面に対して平行に生ずるため、通常外観検
査はもちろん超音波探傷検査でも見逃される危険性が大
きい。また、これらの割れは溶接線に沿ってかなり高い
密度で発生し、構造物にとって危険な存在となり得るこ
とから断制御圧延鋼板適用のメリットをも左右するもの
でありその抑制ないし防止は重要な問題である。Since this crack is located approximately at the center of the thickness of the base metal near the weld metal and occurs parallel to the plate surface, there is a high risk that it will be overlooked not only by regular visual inspections but also by ultrasonic flaw detection. In addition, these cracks occur at a fairly high density along the weld line and can be dangerous to the structure, which affects the merits of applying fracture-controlled rolled steel sheets, and suppressing or preventing them is an important issue. It is.
〈発明の概要〉
本発明は上記した溶接割れの問題を解決するためになさ
れたもので、不純物元素としての〔Ｐ〕の低減、硬化性
としての炭素当量の低減、スラブ加熱温度について最適
組合せを選択することにより高靭性、高溶接性を損うこ
となく、割れの発生を防止したものである。<Summary of the Invention> The present invention has been made to solve the above-mentioned problem of weld cracking, and aims to find an optimal combination of reducing [P] as an impurity element, reducing carbon equivalent as hardenability, and slab heating temperature. This selection prevents cracking without impairing high toughness and high weldability.
造船用鋼板の場合、入熱１００〜７００ＫＪ／ｃｒｎの
１〜２パス溶接が行われるが、このような大入熱溶接と
呼ばれている溶接法では溶接金属に隣接した母材部分は
高温のオーステナイト域温度に加熱され、また冷却速度
は緩慢となる事から硬化は少なく、従来は結晶粒粗大化
に伴なう靭性劣化のみが重視されており、溶接割れにつ
いては問題ないとされていた。In the case of shipbuilding steel plates, one to two pass welding with a heat input of 100 to 700 KJ/crn is performed, but in this welding method called high heat input welding, the base metal part adjacent to the weld metal is exposed to high temperature. Because it is heated to a temperature in the austenite range and the cooling rate is slow, there is little hardening, and in the past, only the deterioration of toughness due to coarsening of crystal grains was emphasized, and weld cracking was considered to be no problem.
しかし本発明者らは断制御圧延鋼板の溶接性改善研究の
過程で大入熱溶接であるにも拘らず先；こ述べた微細な
割れが多発する現象を知見し、その原因と抑制の方法に
ついて検討を進めた結果１割れ感受性のより低い鋼板の
製造方法を発明するに至ったものである。However, in the course of research on improving the weldability of fracture-controlled rolled steel sheets, the present inventors discovered the phenomenon in which the aforementioned microscopic cracks occur frequently despite high heat input welding, and found the causes and methods for suppressing them. As a result of further research on this issue, they came up with a method for producing steel sheets with lower susceptibility to single cracking.
即ち本発明はＣ：０．２０チ以下、ｓｉ：ｏ、ｏｓ〜０
．５０％、Ｍｎ ： ０．５〜２．０％、Ｐ：０．０２
０％以下。That is, in the present invention, C: 0.20 or less, si: o, os~0
．． 50%, Mn: 0.5-2.0%, P: 0.02
Less than 0%.
Ｓ：０．０２０％以下、 ＳｏｌＡｌ： ０．０１５
〜０．１０％。S: 0.020% or less, SolAl: 0.015
~0.10%.
Ｎ：０．０１０％以下を含有し、ＴＡ部鉄及び不可避不
純物からなるスラブをＴＣ≧９４５＋１５７０・Ｃｅ（
１＋２１４・１３ｏｇ ［Ｐａ に加熱後圧延すること
を基本的な特徴とするものである。A slab containing N: 0.010% or less and consisting of TA part iron and inevitable impurities is TC≧945+1570・Ce(
The basic feature is that it is rolled after being heated to 1+214·13 og [Pa].
以下本発明につき詳細に説明する。The present invention will be explained in detail below.
まず１本発明者らは溶接割れの実態を詳細に調査した。First, the present inventors conducted a detailed investigation into the actual state of weld cracking.
第３図は降伏点３６キロ級新制御圧延鋼板の大入熱溶接
継手に発生した割れ４の一例を示すもので、この割れに
は、水素割れの特徴が確められ、溶接金属からの拡散系
水素が板肉のミクロな偏析部に作用して生ずるいわゆる
水素割れである事が明らかとなった。Figure 3 shows an example of a crack 4 that occurred in a high heat input welded joint of a newly controlled rolled steel plate with a yield point of 36 kg. It became clear that so-called hydrogen cracking occurs when system hydrogen acts on microscopic segregation areas in the plate wall.
現在、厚板の製造には連続鋳造（以下ＣＣと略す）の適
用が一般的であり、加えて断制御圧延では低成分系のも
とで高靭性、高強度を得るため、スラブ低温加熱と低温
域での強圧下、低温仕上げが行なわれており、このため
ＣＣスラブ中に生じている成分偏析部での成分拡散が抑
制され、圧延後、水素に対して割れ感受性の高いミクロ
な偏析部が残存するものと考えられる。Currently, continuous casting (hereinafter abbreviated as CC) is commonly applied to the production of thick plates, and in addition, in controlled cutting rolling, low-temperature heating of slabs is used to obtain high toughness and high strength in a low-component system. Strong rolling and low-temperature finishing are carried out in a low-temperature range, which suppresses the diffusion of components in the component segregation areas that occur in the CC slab, and after rolling, the micro-segregation areas that are highly susceptible to cracking due to hydrogen are suppressed. It is thought that some remains.
そこで鋼板のミクロ偏析部に於ける水素割れ感受性を左
右する要因として素鋼のＣＰ）レベルとスラブの加熱条
件に伴なう偏析成分の拡散に着目しこれらによる大入熱
溶接部の割れ抑制効果について調べた。Therefore, we focused on the CP) level of raw steel and the diffusion of segregated components due to slab heating conditions as factors that influence hydrogen cracking susceptibility in micro-segregation areas of steel sheets.The effect of these factors on suppressing cracking in high-heat-input welds is that I looked into it.
第１図は各鋼板について大入熱溶接を行なった場合の割
れ発生率を示している。ここで溶接法は代表的な大入熱
溶接法として、３電極による片面１パスサブマージアー
ク溶接法を用いその入熱量は２２０ＫＪ／ｃｒｎ、溶接
材料は一般に広く使用されている市販の５０キロ鋼用の
ものを用いた。Figure 1 shows the crack occurrence rate when high heat input welding is performed on each steel plate. The welding method here is a one-pass single-pass submerged arc welding method using three electrodes, which is a typical high heat input welding method, and the heat input is 220 KJ/crn, and the welding material is a commercially available 50 kg steel that is widely used. I used the one from
なお、ここで示している割れ発生率は溶接長に対する割
れ長さを表わしており、具体的には連続して採取した側
曲げ試験片での割れ発生本数比率で示している。The crack occurrence rate shown here represents the crack length with respect to the weld length, and specifically, it is shown as the ratio of the number of cracks in side bending test pieces taken continuously.
このグラフより明らかな様に各鋼板の大入熱溶接部割れ
感受性は鋼板の炭素当量、スラブの加熱温度および［”
Ｐ）レベルに依存しており、炭素当量およびＣＰａレベ
ルの低いほど。As is clear from this graph, the high heat input weld cracking susceptibility of each steel plate is affected by the carbon equivalent of the steel plate, the heating temperature of the slab,
P) level dependent, the lower the carbon equivalent and CPa level.
又加熱温度の高いほど割れを低減できることがわかる。It can also be seen that the higher the heating temperature, the more the cracking can be reduced.
一方、鋼板に優れた低温靭性が要求される場合、スラブ
の低温加熱によって圧延前のオーステナイト粒を微細化
する方法が一般的であり、高靭性鋼板では溶接割れの抑
制をスラブ加熱温度のみに求めることは困離である。On the other hand, when a steel plate is required to have excellent low-temperature toughness, it is common to refine the austenite grains before rolling by heating the slab at a low temperature.For high-toughness steel plates, suppression of weld cracking is required only at the slab heating temperature. This is difficult.
しかし、炭素当量および〔Ｐａレベルの低減により従来
の低温加熱でも溶接割れを抑制できることをこのグラフ
は示している。However, this graph shows that weld cracking can be suppressed even with conventional low temperature heating by reducing carbon equivalent and [Pa levels.
次に第２因は第１図を基に作成した図で割れの発生を抑
制するための（Ｐ）レベルと加熱温度の関係を示したも
のである。Next, the second factor is a diagram created based on FIG. 1, which shows the relationship between the (P) level and heating temperature for suppressing the occurrence of cracks.
ここで示される様に割れ抑制に必要なスラブ加熱温度Ｔ
℃と〔Ｐ〕量係の関係はほぼ炭素当量で層別される直線
で表わされる。As shown here, the slab heating temperature T required to suppress cracking
The relationship between degree Celsius and [P] amount ratio is approximately expressed by a straight line stratified by carbon equivalent.
この関係はＴ：Ａ＋Ｂ−Ｃｅｑ ＋ｃ −Ａｏｇ ［Ｐ
ａで表わされ、各係数を実測結果より求めた結果、鋼板
の大入熱溶接部割れを抑制する圧延前の加熱温度条件を
０式で表わすことができる。This relationship is T:A+B-Ceq +c-Aog [P
As a result of determining each coefficient from the actual measurement results, the heating temperature conditions before rolling that suppress cracking in the high heat input weld of the steel plate can be expressed by equation 0.
Ｔ≧９４５＋ １５７０・Ｃｅｑ ＋ ２１４−ｇｏｇ
［Ｐ’：ｌ ＝・・■ここで、Ｔニスラブ加熱温度（
℃）
〔Ｐａ：素鋼のＣＰａ１量（％）
Ｃｅｑ ：素鋼の炭素当量（ＷＥＳ％）ＸＭＱ％十−Ｘ
Ｖ％
したがって、本発明ではスラブ加熱温度を上記０式で示
す温度とする。T≧945+ 1570・Ceq+214-gog
[P':l =... ■Here, T varnish slab heating temperature (
℃) [Pa: CPa1 amount of raw steel (%) Ceq: Carbon equivalent (WES%) of raw steel
V% Therefore, in the present invention, the slab heating temperature is set to the temperature shown by the above equation 0.
圧延条件については特に限定はないが、母材靭性を高め
るためには９００℃以下での累積圧下率を一定以上とる
制御圧延を行うことが望ましく、累積圧下率３０％以上
とするのが望ましい。There are no particular limitations on the rolling conditions, but in order to improve the toughness of the base material, it is desirable to perform controlled rolling at a temperature of 900° C. or lower with a cumulative reduction rate of at least a certain level, and it is desirable that the cumulative reduction rate is 30% or more.
また、母材強度及び靭性を高めるためには通常の圧延で
あっても又制御圧延であっても。In addition, in order to increase the strength and toughness of the base material, regular rolling or controlled rolling may be used.
圧延直後加速冷却することが有効である。It is effective to perform accelerated cooling immediately after rolling.
この加速冷却時の冷却速度が３℃／ｓｅｃ未満では上記
の効果が明瞭に現われず、又３０℃／ｓｅｃを超えると
マルテンサイト等の低温変態生成物が生ずるようになる
ため３〜ｂ
なければならない。又当該加速冷却を４００℃未満まで
続けると鋼板の変形が大きくなるため圧延終了直後から
４００℃以上までの１００℃以上の温度巾にわたり上記
の加速冷却を行い、以後放冷する必要がある。If the cooling rate during this accelerated cooling is less than 3°C/sec, the above effects will not be apparent, and if it exceeds 30°C/sec, low-temperature transformation products such as martensite will be generated, so 3 to b are required. It won't happen. Further, if the accelerated cooling is continued to less than 400°C, the deformation of the steel sheet becomes large, so it is necessary to perform the accelerated cooling as described above over a temperature range of 100°C or more from immediately after the end of rolling to 400°C or more, and then allow it to cool.
次に本発明における成分限定を説明する。Next, the limitation of ingredients in the present invention will be explained.
Ｃ：Ｃは強度確保の上から有効な元素であるが、これが
０．２０％を超えると母材の靭性劣化および溶接部での
硬化、靭性劣化が太きいためこれを上限とし、０．２０
％以下とする。C: C is an effective element for ensuring strength, but if it exceeds 0.20%, the toughness of the base metal will deteriorate, hardening at the welded part, and toughness will deteriorate, so this is the upper limit, and 0.20%
% or less.
Ｓｉ ： Ｓｉは脱酸並びに強化元素として添加するが
０．０５％未満ではその効果が明瞭でないため、これを
下限とし、且つ０．５％を超えてはＣ同様溶接性を劣化
させるため、０．０５〜０．５０％の範囲とする。Si: Si is added as a deoxidizing and reinforcing element, but if it is less than 0.05%, the effect is not clear, so this is the lower limit, and if it exceeds 0.5%, it deteriorates weldability like C, so 0. The range is .05% to 0.50%.
Ｍｎ ： Ｍｎは強度、靭性確保の点から必項元素であ
る。しかし、これが０．５％未満では効果が小さく、且
つ２．０％を超えては溶接性を悪化させるため、０．５
〜２．０％の範囲とする。Mn: Mn is an essential element from the viewpoint of ensuring strength and toughness. However, if it is less than 0.5%, the effect is small, and if it exceeds 2.0%, weldability deteriorates, so 0.5%
-2.0% range.
ｐｏｐは原材料から不可避に混入する不純物元素である
。Ｐは局部的な偏析を生じ易く、偏析部の硬化、脆化に
大きな影響がある。従ってＰは極力低く押えることが望
ましいがこれを大巾に低減するには製造プロセス上困難
を伴う。しかしＰの低減は本発明の目的である大入熱溶
接部の割れ抑止に効果が大きい事からその上限を先に述
べたスラブ加熱温度との関連で示される値以下とし、且
つ現状の製造プロセスで比較的容易に達成できる０、０
２０係以下とする。POP is an impurity element that is inevitably mixed in from raw materials. P tends to cause local segregation and has a large effect on hardening and embrittlement of the segregated areas. Therefore, it is desirable to keep P as low as possible, but it is difficult to reduce P to a large extent in terms of the manufacturing process. However, since reducing P is highly effective in suppressing cracking in high-heat-input welds, which is the objective of the present invention, the upper limit should be set below the value shown in relation to the slab heating temperature mentioned above, and the current manufacturing process. 0,0 which can be achieved relatively easily with
No more than 20 staff members.
ｓｒｓも原材料から不可避に混入する不純物元素であり
、その増加によって鋼板の延靭性は劣化するため、０．
０２０％を上限とする。SRS is also an impurity element that is unavoidably mixed in from raw materials, and its increase deteriorates the ductility of the steel plate, so 0.
The upper limit is 0.020%.
Ｓｏｔ、ｋｔ： Ａｔは鋼の脱酸上必要な添加元素であ
り、且つ鋼中の窒素をＡｔＮとして固定することで組織
の微細化、靭性の改善に有効であり、０．０１５％をそ
の下限とする。Sot, kt: At is an additive element necessary for deoxidizing steel, and is effective in refining the structure and improving toughness by fixing nitrogen in steel as AtN, and its lower limit is 0.015%. shall be.
しかし、これがｏ、ｉｏｏ％を超えると清浄性が悪化し
溶接性を損なうためこれを上限とする。However, if this exceeds o, ioo%, cleanliness deteriorates and weldability is impaired, so this is set as the upper limit.
ＮＵＮは銅の梢錬過程で混入し、ｆｒｅｅのＮとしては
靭性を劣化させ低い方が望ましいが、Ａｔ等の窒化物生
成元素と結合し適正量存在することで組織、靭性の改善
、或いは溶接部の靭性劣化を防止する効果を有する。し
かし、これが０．０１０％を超えると靭性の劣化が大き
いため、これを上限とする。NUN is mixed in during the copper refining process, and as a free N, it deteriorates toughness and is preferably lower. However, by combining with nitride-forming elements such as At and existing in an appropriate amount, it can improve the structure and toughness, and improve welding. This has the effect of preventing deterioration of the toughness of the parts. However, if this exceeds 0.010%, the toughness deteriorates significantly, so this is set as the upper limit.
以上の元素に加えて更に下記元素を必要に応じて１種又
は２種以上添加することが可能である。In addition to the above elements, one or more of the following elements may be added as necessary.
Ｔｉ ： ＴｉはＮを固定するために有効な元素であり
ｗｆｒｅｅＮの低減により靭性を改善する。またＮ量と
の間にＴｉ／Ｎ ’：： ３．４が成り立つ適正量のＴ
ｉの添加により大入熱溶接部の靭性を改善する。しかし
ＴＩが０．０２０受を超えると靭性が劣化するためこれ
を上限とする。Ti: Ti is an effective element for fixing N and improves toughness by reducing wfreeN. Also, an appropriate amount of T that satisfies Ti/N':: 3.4 with the amount of N.
The addition of i improves the toughness of high heat input welds. However, if the TI exceeds 0.020, the toughness deteriorates, so this is set as the upper limit.
Ｃｕ ： Ｃｕは鋼板の強度を高めるのに有効な元素で
あり、Ｃと置換することで炭素当量を低減し溶接性を改
善することができる。Cu: Cu is an effective element for increasing the strength of steel sheets, and by replacing it with C, the carbon equivalent can be reduced and weldability can be improved.
しかし、多量に添加すると熱間圧延中に表面疵が生成し
やすくなるため、０．５％を上限とする。However, if added in a large amount, surface flaws are likely to occur during hot rolling, so the upper limit is set at 0.5%.
Ｎｉ：Ｎｉは溶接性を損なう事なく、強度および靭性を
向上させる。しかし、１．０％を超える添加は経済的に
好ましくないためこれを上限とする。Ni: Ni improves strength and toughness without impairing weldability. However, since adding more than 1.0% is economically undesirable, this is the upper limit.
Ｎｂ ： Ｎｂは制御圧延効果を高め、高強度、高靭性
を得るのに有効である。しかし、
００５０％以上では溶接による靭性劣化が顕著となるた
め、これを上限とする。Nb: Nb is effective in enhancing the controlled rolling effect and obtaining high strength and high toughness. However, if it exceeds 0.050%, the toughness deteriorates significantly due to welding, so this is set as the upper limit.
■：ｖは鋼板の強度靭性を高める効果がある。■: v has the effect of increasing the strength and toughness of the steel plate.
しかし、これが０．１０％を超えると溶接部の靭性を損
なう事からこれを上限とする。However, if this exceeds 0.10%, the toughness of the welded part will be impaired, so this is set as the upper limit.
炭素当量（Ｃｅｑ） ：炭素当量は鋼材の強度や溶接熱
影響部の硬化度を計画するパラメータであるが鋼材のミ
クロ偏析部での硬化度に対しても影響する。このため炭
素当量は本発明の目的である割れ防止の観点から低いほ
ど好ましいが鋼材材質確保を考慮して、 ｖｌＦ、Ｓに
よる炭素当量の上限を１式で与えられる値以下とする。Carbon equivalent (Ceq): Carbon equivalent is a parameter for planning the strength of steel materials and the hardening degree of the weld heat affected zone, but it also affects the hardening degree of micro-segregation parts of steel materials. Therefore, from the viewpoint of preventing cracking, which is the object of the present invention, it is preferable that the carbon equivalent is as low as possible; however, in consideration of ensuring the quality of the steel material, the upper limit of the carbon equivalent based on vlF,S is set to be less than the value given by equation 1.
〈実施例〉
第１表に示す成分の６鋼をＣＣスラブを用いて、制御圧
延或いは制御圧延後加速冷却することにより、降伏点３
６キロ級５０キロ鋼版を得た。ここで鋼Ａ−Ｃはｗｐｓ
による炭素当量が０．３３％、鋼Ｄ−Ｇは０．３６％、
鋼Ｈ〜Ｊは０４０％を中心とした５ｉ−ｈｔｎ系、鋼に
およびＬは０．３３％のＮｂおよびＶ系で、各々［Ｐ）
レベルを変えている。これら６鋼の成分はすべて本発明
の範囲内である。<Example> Six steels having the components shown in Table 1 were subjected to controlled rolling or accelerated cooling after controlled rolling using a CC slab to achieve a yield point of 3.
A 6 kg class 50 kg steel plate was obtained. Here steel A-C is wps
The carbon equivalent is 0.33%, steel D-G is 0.36%,
Steels H to J are 5i-htn based on 040%, steel and L are 0.33% Nb and V based, respectively [P]
changing levels. The components of these six steels are all within the scope of the present invention.
上記鋼をスラブ加熱温度を種々かえて３２鴎、２５■板
厚の鋼板とし、その機絨的性質と溶接部割れ発生率を求
めた。その結果を第２表に示す。本発明材の場合、いず
れも溶接部割れ発生率がＯであり、また俄械的性質も優
れていることがわかる。The above-mentioned steel was made into steel plates with a thickness of 32 mm and a thickness of 25 mm by varying the slab heating temperature, and the mechanical properties and weld crack occurrence rate were determined. The results are shown in Table 2. In the case of the materials of the present invention, the weld crack occurrence rate was O in all cases, and it was found that the mechanical properties were also excellent.
第１図はスラブ加熱温度と大入熱溶接部割れ発生率との
関係を示すグラフ、第２図は〔Ｐ″ｌ量とスラブ加熱温
度との関係を示すグラフ、第３図は金属組織の顕微鏡写
真である。
特許出願人 日本鋼管株式会社
発 明 者 束 １） 辛 四 部間
平 林 清 部同
山 崎 喜 部同
谷 三 部間
伊 沢 撤回
石 川 Ｍｊ代理人弁理士
吉 原 省 部同 同
高 橋 部同 弁獲士
吉 原 弘 子第 ２ 図
【円ｉ （％）
第３図Figure 1 is a graph showing the relationship between slab heating temperature and high heat input weld crack occurrence rate, Figure 2 is a graph showing the relationship between [P″l amount and slab heating temperature, and Figure 3 is a graph showing the relationship between the metallographic structure and This is a microscopic photograph. Patent applicant: Nippon Kokan Co., Ltd. Inventor: 1) Shin Shibuma
Kiyoshi Hirabayashi
Yoshi Yamazaki
Tani three parts
Izawa withdrawal
Mj Ishikawa, Patent Attorney, Yoshihara, Mj.
Bento Takahashi
Hiroko Yoshihara Figure 2 [Circle i (%) Figure 3]
Claims (1)
、Ｍｎ：０．５〜２．０％、Ｐ：０．０２０％以下、Ｓ
：０．０２０％以下、ＳｏｌＡｌ：０．０１５〜０．１
０％、Ｎ：０．０１０％以下を含有し、残部鉄及び不可
避不純物からなるスラブを、下式 を満足する温度Ｔ℃に加熱後圧延することを特徴とする
溶接割れ感受性の低い非調質高張力鋼板の製造方法。 Ｔ≧９４５＋１５７０・Ｃｅｑ＋２１４ｌｏｇ〔Ｐ〕〔
但し、Ｃｅｑ：素鋼の炭素当量（ＷＥＳ％）〔Ｐ〕：素
鋼のリン含有量（％）〕 ２、Ｃ：０．２０％以下、Ｓｉ：０．０５〜０．５０％
、Ｍｎ：０．５〜２．０％、Ｐ：０．０２０％以下、Ｓ
：０．０２０％以下、ＳｏｌＡｌ：０．０１５〜０．１
０％、Ｎ：０．０１０％以下、更にＣｕ：０．５％以下
、Ｎｉ：１．０％以下、Ｎｂ：０．０５％以下、Ｖ：０
．１０％以下、Ｔｉ：０．０２％以下の中１種又は２種
以上を含有し、残部鉄及び不可避不純物からなるスラブ
を、下式を満足する温度Ｔ℃に加熱後圧延することを特
徴とする溶接割れ感受性の低い非調質高張力鋼板の製造
方法。 Ｔ≧９４５＋１５７０・Ｃｅｑ＋２１４ｌｏｇ〔Ｐ〕〔
但しＣｅｑ：素鋼の炭素当量（ＷＥＳ％）〔Ｐ〕：素鋼
のリン含有量（％）〕 ３、Ｃ：０．２０％以下、Ｓｉ：０．０５〜０．５０％
、Ｍｎ：０．５〜２．０％、Ｐ：０．０２０％以下、Ｓ
：０．０２０％以下、ＳｏｌＡｌ：０．０１５〜０．１
０％、Ｎ：０．０１０％以下を含有し、残部鉄及び不可
避不純物からなるスラブを、下式を満足する温度Ｔ℃に
加熱後圧延し、圧延直後から４００℃までの１００℃以
上の温度巾にわたり３〜３０℃／ｓｅｃの冷却速度で加
速冷却し、以後放冷することを特徴とする溶接割れ感受
性の低い非調質高張力鋼板の製造方法。 Ｔ≧９４５＋１５７０・Ｃｅｑ＋２１４ｌｏｇ〔Ｐ〕〔
但しＣｅｑ：素鋼の炭素当量（ＷＥＳ％）〔Ｐ〕：素鋼
のリン含有量（％）〕 ４、Ｃ：０．２０％以下、Ｓｉ：０．０５〜０．５０％
、Ｍｎ：０．５〜２．０％、Ｐ：０．０２０％以下、Ｓ
：０．０２０％以下、ＳｏｌＡｌ：０．０１５〜０．１
０％、Ｎ：０．０１０％以下、更にＣｕ：０．５％以下
、Ｎｉ：１．０％以下、Ｎｂ：０．０５％以下、Ｖ：０
．１０％以下、Ｔｉ：０．０２％以下の中１種又は２種
以上を含有し、残部鉄及び不可避不純物からなるスラブ
を、下式を満足する温度Ｔ℃に加熱後圧延し、圧延直後
から４００℃までの１００℃以上の温度巾にわたり３〜
３０℃／ｓｅｃの冷却速度で加速冷却し、以後放冷する
ことを特徴とする溶接割れ感受性の低い非調質高張力鋼
板の製造方法。 Ｔ≧９４５＋１５７０・Ｃｅｑ＋２１４ｌｏｇ〔Ｐ〕〔
但しＣｅｑ：素鋼の炭素当量（ＷＥＳ％）〔Ｐ〕：素鋼
のリン含有量（％）〕[Claims] 1. C: 0.20% or less, Si: 0.05 to 0.50%
, Mn: 0.5-2.0%, P: 0.020% or less, S
: 0.020% or less, SolAl: 0.015 to 0.1
0%, N: 0.010% or less, the balance consisting of iron and unavoidable impurities, is heated to a temperature T°C that satisfies the following formula and then rolled. A method for manufacturing high-strength steel plates. T≧945+1570・Ceq+214log[P][
However, Ceq: carbon equivalent of raw steel (WES%) [P]: phosphorus content (%) of raw steel] 2, C: 0.20% or less, Si: 0.05 to 0.50%
, Mn: 0.5-2.0%, P: 0.020% or less, S
: 0.020% or less, SolAl: 0.015 to 0.1
0%, N: 0.010% or less, Cu: 0.5% or less, Ni: 1.0% or less, Nb: 0.05% or less, V: 0
．． 10% or less, Ti: 0.02% or less, a slab containing one or more of Ti: 0.02% or less, the balance consisting of iron and unavoidable impurities, is heated to a temperature T ° C that satisfies the following formula and then rolled. A method for manufacturing non-tempered high-strength steel sheets with low weld cracking susceptibility. T≧945+1570・Ceq+214log[P][
However, Ceq: carbon equivalent of raw steel (WES%) [P]: phosphorus content (%) of raw steel] 3, C: 0.20% or less, Si: 0.05 to 0.50%
, Mn: 0.5-2.0%, P: 0.020% or less, S
: 0.020% or less, SolAl: 0.015 to 0.1
A slab containing 0%, N: 0.010% or less, the balance consisting of iron and unavoidable impurities is heated to a temperature T°C that satisfies the following formula and then rolled, and then rolled at a temperature of 100°C or more from immediately after rolling to 400°C. A method for producing a non-tempered high-strength steel sheet with low weld cracking susceptibility, characterized by performing accelerated cooling over the width at a cooling rate of 3 to 30° C./sec, and then allowing it to cool. T≧945+1570・Ceq+214log[P][
However, Ceq: Carbon equivalent of raw steel (WES%) [P]: Phosphorus content (%) of raw steel] 4, C: 0.20% or less, Si: 0.05 to 0.50%
, Mn: 0.5-2.0%, P: 0.020% or less, S
: 0.020% or less, SolAl: 0.015 to 0.1
0%, N: 0.010% or less, Cu: 0.5% or less, Ni: 1.0% or less, Nb: 0.05% or less, V: 0
．． A slab containing Ti: 10% or less, Ti: 0.02% or less, and the remainder consisting of iron and unavoidable impurities is heated to a temperature T°C that satisfies the following formula and then rolled. 3 to 400℃ over a temperature range of 100℃ or more
A method for producing a non-heat treated high tensile strength steel sheet with low weld cracking susceptibility, characterized by performing accelerated cooling at a cooling rate of 30° C./sec and then allowing it to cool. T≧945+1570・Ceq+214log[P][
However, Ceq: Carbon equivalent of raw steel (WES%) [P]: Phosphorus content (%) of raw steel]
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61021201A JPH0753882B2 (en) | 1986-02-04 | 1986-02-04 | Method for producing non-heat treated high strength steel plate with low weld crack susceptibility |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61021201A JPH0753882B2 (en) | 1986-02-04 | 1986-02-04 | Method for producing non-heat treated high strength steel plate with low weld crack susceptibility |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62180013A true JPS62180013A (en) | 1987-08-07 |
| JPH0753882B2 JPH0753882B2 (en) | 1995-06-07 |
Family
ID=12048363
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61021201A Expired - Fee Related JPH0753882B2 (en) | 1986-02-04 | 1986-02-04 | Method for producing non-heat treated high strength steel plate with low weld crack susceptibility |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0753882B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03211251A (en) * | 1989-04-26 | 1991-09-17 | Nippon Steel Corp | High strength for welding structure having excellent fracture toughness in heat affected zone |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5217319A (en) * | 1975-06-26 | 1977-02-09 | Nippon Steel Corp | Production process of hot rolled steel material for working and its tr eatment method |
| JPS5254611A (en) * | 1975-10-31 | 1977-05-04 | Nippon Kokan Kk <Nkk> | Steel for lrge heat input welding |
| JPS54115619A (en) * | 1978-02-28 | 1979-09-08 | Kobe Steel Ltd | Steel for welded structure with superior toughness and weld crack resistance in weld heat-affected zone |
| JPS5538901A (en) * | 1978-03-17 | 1980-03-18 | Nippon Kokan Kk <Nkk> | Manufacture of unrefined steel sheet having excellent hydrogen cracking resistance in wet hydrogen sulfide environment of high hydrogen ion concentration |
| JPS55128533A (en) * | 1979-03-23 | 1980-10-04 | Sumitomo Metal Ind Ltd | Preparation of steel material with reduced microsegregation |
| JPS572838A (en) * | 1980-06-09 | 1982-01-08 | Nippon Steel Corp | Production of steel material having uniform internal quality |
| JPS57120614A (en) * | 1981-01-16 | 1982-07-27 | Nippon Steel Corp | Method for producing steel material from ingot |
| JPS60125324A (en) * | 1983-12-12 | 1985-07-04 | Kawasaki Steel Corp | Production of high-tensile high-toughness steel plate |
| JPS60152626A (en) * | 1984-01-20 | 1985-08-10 | Kawasaki Steel Corp | Method for stabilizing toughness of high tension steel for welded structure |
| JPS6123714A (en) * | 1984-07-12 | 1986-02-01 | Nippon Steel Corp | Manufacture of steel having superior toughness at low temperature in weld heat-affected zone |
| JPS6256554A (en) * | 1985-09-04 | 1987-03-12 | Kobe Steel Ltd | Accelerated cooling steel plate causing no ust defect in heat affected zone of high heat input welding |
-
1986
- 1986-02-04 JP JP61021201A patent/JPH0753882B2/en not_active Expired - Fee Related
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5217319A (en) * | 1975-06-26 | 1977-02-09 | Nippon Steel Corp | Production process of hot rolled steel material for working and its tr eatment method |
| JPS5254611A (en) * | 1975-10-31 | 1977-05-04 | Nippon Kokan Kk <Nkk> | Steel for lrge heat input welding |
| JPS54115619A (en) * | 1978-02-28 | 1979-09-08 | Kobe Steel Ltd | Steel for welded structure with superior toughness and weld crack resistance in weld heat-affected zone |
| JPS5538901A (en) * | 1978-03-17 | 1980-03-18 | Nippon Kokan Kk <Nkk> | Manufacture of unrefined steel sheet having excellent hydrogen cracking resistance in wet hydrogen sulfide environment of high hydrogen ion concentration |
| JPS55128533A (en) * | 1979-03-23 | 1980-10-04 | Sumitomo Metal Ind Ltd | Preparation of steel material with reduced microsegregation |
| JPS572838A (en) * | 1980-06-09 | 1982-01-08 | Nippon Steel Corp | Production of steel material having uniform internal quality |
| JPS57120614A (en) * | 1981-01-16 | 1982-07-27 | Nippon Steel Corp | Method for producing steel material from ingot |
| JPS60125324A (en) * | 1983-12-12 | 1985-07-04 | Kawasaki Steel Corp | Production of high-tensile high-toughness steel plate |
| JPS60152626A (en) * | 1984-01-20 | 1985-08-10 | Kawasaki Steel Corp | Method for stabilizing toughness of high tension steel for welded structure |
| JPS6123714A (en) * | 1984-07-12 | 1986-02-01 | Nippon Steel Corp | Manufacture of steel having superior toughness at low temperature in weld heat-affected zone |
| JPS6256554A (en) * | 1985-09-04 | 1987-03-12 | Kobe Steel Ltd | Accelerated cooling steel plate causing no ust defect in heat affected zone of high heat input welding |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03211251A (en) * | 1989-04-26 | 1991-09-17 | Nippon Steel Corp | High strength for welding structure having excellent fracture toughness in heat affected zone |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0753882B2 (en) | 1995-06-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0488222B1 (en) | Method of producing clad steel plate having good low-temperature toughness | |
| EP2305850B1 (en) | High-strength thick steel products excellent in toughness and weldability, high-strength ultra-thick h shape steel and processes for manufacturing both | |
| JP5407478B2 (en) | High-strength thick steel plate with excellent toughness of heat-affected zone of single layer large heat input welding and method for producing the same | |
| JPS63241114A (en) | Manufacture of high toughness and high tension steel having superior resistance to stress corrosion cracking | |
| JPH02220735A (en) | Production of high tensile strength steel for welding and low temperature including titanium oxide | |
| JPS626730B2 (en) | ||
| JPH0636993B2 (en) | Method for producing stainless clad steel sheet with excellent corrosion resistance and toughness | |
| JP2013129885A (en) | Method of producing high-strength thick steel plate excellent in brittle crack propagation arrest property | |
| JPS625216B2 (en) | ||
| JP2005097694A (en) | Method for manufacturing non-heat-treated high-strength thick steel plate superior in brittle crack arrestability | |
| JPH06128631A (en) | Production of high manganese ultrahigh tensile strength steel excellent in low temperature toughness | |
| JP2541070B2 (en) | Method for producing high nickel alloy clad steel sheet with excellent brittle fracture propagation stopping properties of base material | |
| JPH11131177A (en) | Steel plate for medium-or ordinary-temperature pressure vessel, capable of omitting post weld heat treatment, and its production | |
| JP2002224835A (en) | Method of welding high toughness high tension steel having excellent weld heat influence zone toughness | |
| JPS62180013A (en) | Manufacture of nontemper high tension steel plate having low welding crack susceptibility | |
| JP2706159B2 (en) | Method for producing low yield ratio high strength steel with good weldability | |
| JP3736209B2 (en) | High tensile steel with excellent weld toughness and manufacturing method thereof | |
| JPH0227407B2 (en) | YOSETSUSEINISUGURETAKOKYODOKONOSEIZOHOHO | |
| JPH07286213A (en) | Production of thick hot coil good in dwtt property | |
| JP3367388B2 (en) | High ductility and high toughness steel sheet and manufacturing method thereof | |
| JPH0319285B2 (en) | ||
| JP2001049385A (en) | High tensile strength steel excellent in weld zone toughness and its production | |
| JPH05271757A (en) | Manufacture of steel sheet for low temperature use | |
| JP2005281816A (en) | High strength cold rolled steel sheet having satisfactory formability and excellent projection weldability, and production method therefor | |
| JPS63145711A (en) | Production of high tension steel plate having excellent low temperature toughness |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |