JPH01168819A - Manufacture of steel plate with composite structure having high ductility and high strength - Google Patents
Manufacture of steel plate with composite structure having high ductility and high strengthInfo
- Publication number
- JPH01168819A JPH01168819A JP32727987A JP32727987A JPH01168819A JP H01168819 A JPH01168819 A JP H01168819A JP 32727987 A JP32727987 A JP 32727987A JP 32727987 A JP32727987 A JP 32727987A JP H01168819 A JPH01168819 A JP H01168819A
- Authority
- JP
- Japan
- Prior art keywords
- strength
- austenite
- steel
- range
- temperature range
- 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.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 40
- 239000010959 steel Substances 0.000 title claims abstract description 40
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 11
- 239000002131 composite material Substances 0.000 title abstract description 5
- 229910001566 austenite Inorganic materials 0.000 claims abstract description 44
- 229910001563 bainite Inorganic materials 0.000 claims abstract description 25
- 230000000717 retained effect Effects 0.000 claims abstract description 23
- 238000001816 cooling Methods 0.000 claims abstract description 22
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 10
- 239000012535 impurity Substances 0.000 claims abstract description 7
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 3
- 239000000463 material Substances 0.000 claims description 4
- 239000000203 mixture Substances 0.000 abstract description 9
- 238000000034 method Methods 0.000 abstract description 8
- 238000010438 heat treatment Methods 0.000 abstract description 6
- 229910052799 carbon Inorganic materials 0.000 abstract description 3
- 230000009466 transformation Effects 0.000 description 18
- 230000000694 effects Effects 0.000 description 13
- 229910000734 martensite Inorganic materials 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 229910001562 pearlite Inorganic materials 0.000 description 4
- 230000000087 stabilizing effect Effects 0.000 description 4
- 150000001247 metal acetylides Chemical class 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- JIGWWGDIEUWCOR-UHFFFAOYSA-N 3-(1,4-diazabicyclo[3.2.2]nonan-4-yl)-6-fluorodibenzothiophene 5,5-dioxide Chemical compound C1=C2S(=O)(=O)C=3C(F)=CC=CC=3C2=CC=C1N1CCN2CCC1CC2 JIGWWGDIEUWCOR-UHFFFAOYSA-N 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/008—Heat treatment of ferrous alloys containing Si
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、延性の優れた高強度鋼板の製造方法に関し、
とくに残留オーステナイトを含む複合組織を有すること
により１強度６０ｋｇｆ／ａｎ”以上１００ｋｇｆ／ｍ
ｍ”未満で優れた延性を示す高強度鋼板の製造方法に関
する。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a high-strength steel plate with excellent ductility.
In particular, by having a composite structure containing retained austenite, the single strength is 60 kgf/an'' or more and 100 kgf/m.
The present invention relates to a method for producing a high-strength steel plate that exhibits excellent ductility at a strength of less than 100 m.
（従来の技術）
近年、自動車用鋼板として延性の優れた高強度鋼板を要
望する声が強く、それに応えて種々の高強度鋼板が開発
されている。たとえば引張強さ（ＴＳ）が６０ｋｇｆ／
ａｍ”以上の高強度鋼板としては特公昭５６−１１７４
１号で提示されているいわゆるＤＰＭ（Ｄｕａｌ Ｐｈ
ａｓｅｍ ：フエライト＋マルテンサイト２相組織１１
Ｉｌ）が開発されている。 ＤＰ錆の特徴は、降伏点が
ないこと、降伏比が低いこと、延性が他の固溶強化鋼や
析出強化鋼に比べ高いことで知られている。しかしなが
らこのＤＰ鋼にしても伸び（Ｅｌ）はＴＳ ６０ｋｇｆ
／ａｓ”級で約３０％１丁Ｓ １００ｋｇｆ／ｍｕ”級
では約１５％であり、強度と延性のバランスを示すＴＳ
ＸＥｌの値が１８００〜１５００にしか過ぎず、さらに
高延性を要望されているのが現状である。(Prior Art) In recent years, there has been a strong demand for high-strength steel sheets with excellent ductility as steel sheets for automobiles, and in response to this demand, various high-strength steel sheets have been developed. For example, the tensile strength (TS) is 60kgf/
As a high-strength steel plate with a strength of 56-1174
The so-called DPM (Dual Ph
asem: Ferrite + martensite two-phase structure 11
Il) has been developed. DP rust is known to have no yield point, low yield ratio, and high ductility compared to other solid solution strengthened steels and precipitation strengthened steels. However, even with this DP steel, the elongation (El) is TS 60kgf
/as" class is about 30% 1 piece S 100kgf/mu" class is about 15%, which shows the balance between strength and ductility.
Currently, the value of XEl is only 1800 to 1500, and even higher ductility is desired.
このような高強度鋼板の延性改善を図る手段として、残
留オーステナイトのＴＲＩＰ （Ｔｒａｎｓｆｏｒｍａ
ｔｉｏｎＩｎｄｕｃｅｄ Ｐｌａｓｔｉｃｉｔｙ ：変
態誘起塑性）を利用した方法が特公昭節５８−４２２４
６号に提示されている。この方法によればＴＳが１００
ｋｇｆ／ｍｍ”以上でＥｌが３０％以上を示し、ＴＳＸ
Ｅｌの値が約３，０００を超す高延性高強度鋼板の製造
が可能である。しかしながら該方法ではＣが０．３５〜
０．８５と高いことから溶接性に劣るため、自動車用鋼
板としての適用性は狭いものであった。As a means of improving the ductility of such high-strength steel sheets, retained austenite (TRIP)
A method using transformation-induced plasticity (transformation-induced plasticity) was published in 1986-4224.
It is presented in No. 6. According to this method, TS is 100
kgf/mm" or more, El shows 30% or more, TSX
It is possible to produce a highly ductile and high strength steel sheet with an El value of more than about 3,000. However, in this method, C is 0.35~
Since the weldability is as high as 0.85, its applicability as a steel plate for automobiles is limited.
（発明が解決しようとする問題点）
本発明は前述したような従来技術の問題点を解決し、溶
接性を満足できる範囲の低Ｃ含有量で。(Problems to be Solved by the Invention) The present invention solves the problems of the prior art as described above, and has a low C content within a range that satisfies weldability.
なおかつＴＲＩＰ効果を発揮するに充分な量の残留オー
ステナイトを含有する、延性の優れた６０ｋｇｆ／ ｍ
ｍ ”以上１００ｋｇｆ／ｍｍ２未満の強度を有する高
強度鋼板の製造方法を提供するものである。Furthermore, it contains a sufficient amount of retained austenite to exhibit the TRIP effect, and has excellent ductility of 60 kgf/m.
The present invention provides a method for manufacturing a high-strength steel plate having a strength of not less than m'' and less than 100 kgf/mm2.
（問題点を解決するための手段）
本発明は残留オーステナイトのＴＲＩＰ効果を利用する
ことで優れた延性を有する高強度低炭素鋼板を得ようと
するものであり、α＋γ２相域に加熱して得られるオー
ステナイトのＣ濃度をベイナイト変態を利用してさらに
濃縮することにより高Ｃ濃度の残留オーステナイトとし
てフェライトとベイナイトと共存させることにより製造
できる。(Means for Solving the Problems) The present invention aims to obtain a high-strength, low-carbon steel plate with excellent ductility by utilizing the TRIP effect of retained austenite. By further concentrating the C concentration of the austenite produced by using bainite transformation, residual austenite with a high C concentration can be produced by making it coexist with ferrite and bainite.
（発明の構成）
すなわち、本発明は重量％で、Ｃ：０．０５〜０．２５
％、Ｓｉ：１．ＯＯ〜３．００％、Ｍｎ：０．２０〜１
．５０％、必要ならばさらにＮｉ ： ０ 、２０〜１
．００％ を含み残部Ｆｅおよび不可避的不純物からな
る鋼を、Ａｃ工＋３０℃〜Ａｃ、の温度域に加熱し３０
ｓｅｃ〜１５ｍｉｎ保持した後、３５０〜５００℃の温
度域まで冷却速度１０〜５００℃／ｓｅｃで冷却し、該
温度域で３０ｓｅｃ〜３０ｍｉｎ保持した後、室温まで
冷却することによりフェライトとベイナイトを主相とし
、さらに１０％以上の残留オーステナイトを含有するこ
とを特徴とする延性の優れた高強度鋼板の製造方法であ
る。(Structure of the invention) That is, the present invention has C: 0.05 to 0.25 in weight%.
%, Si:1. OO~3.00%, Mn:0.20~1
．． 50%, additional Ni if necessary: 0, 20-1
．． 00%, the balance being Fe and unavoidable impurities, is heated to a temperature range of +30°C to Ac.
sec to 15 min, then cooled to a temperature range of 350 to 500°C at a cooling rate of 10 to 500°C/sec, held in this temperature range for 30 sec to 30 min, and cooled to room temperature to convert ferrite and bainite into main phases. and further contains 10% or more of retained austenite.
本発明方法は熱延材、冷延材を含めて適用される。好ま
しくは厚さ６ｍａ＋以下の板材に適用される。The method of the present invention is applicable to both hot-rolled and cold-rolled materials. Preferably, it is applied to a plate material having a thickness of 6 ma+ or less.
本発明方法の素材となる鋼の成分範囲の限定理由につい
て述べる。The reason for limiting the range of composition of steel that is the raw material for the method of the present invention will be described.
Ｃはオーステナイト中に濃化することにより残留オース
テナイトを安定化させる効果を有するとともに、鋼の強
度に寄与する重要な元素である。C is an important element that has the effect of stabilizing retained austenite by concentrating in austenite, and also contributes to the strength of steel.
０．０５％未満では強度を確保することが困難である上
、残留オーステナイトを１０％以上含有させることが困
難である。一方、Ｃ含有量を増加させれば強度の確保は
容易であり、残留オーステナイトの確保も容易であるが
０．２５％を越えて添加すると溶接性の劣化が著しい、
そこでＣ含有量の下限を０．０３％、上限を０．２５％
とした。If it is less than 0.05%, it is difficult to ensure strength, and it is also difficult to contain 10% or more of retained austenite. On the other hand, if the C content is increased, it is easy to ensure strength and retained austenite, but if it is added in excess of 0.25%, weldability deteriorates significantly.
Therefore, the lower limit of C content was set at 0.03% and the upper limit was set at 0.25%.
And so.
Ｓｉはベイナイト変態において未変態オーステナイトへ
のＣの濃化を促進するとともにフェライトとベイナイト
の強度に寄与する重要な元素である。Si is an important element that promotes the concentration of C in untransformed austenite during bainite transformation and contributes to the strength of ferrite and bainite.
本発明のＣ含有量範囲では、 Ｓｉ含有量が１．００％
未満ではその作用は十分ではない。一方、Ｓｉ含有量が
３．００％を超えてもその効果は飽和するのみならず、
Ａｃ＝変態の上昇を招いて製造性が著しく低下する。In the C content range of the present invention, the Si content is 1.00%
If the amount is less than that, the effect is not sufficient. On the other hand, even if the Si content exceeds 3.00%, the effect not only becomes saturated;
Ac=Increase in transformation and significantly reduce manufacturability.
そこで、Ｓｉ含有量の下限を１．００％、上限を３．０
０％とした。Therefore, the lower limit of Si content was set to 1.00%, and the upper limit was set to 3.0%.
It was set to 0%.
Ｍｎは一般にオーステナイト安定化元素でありＡｃ工、
Ａｃ、変態点を低下させる効果を有する元素として知
られているが、本発明においてはＡｃ１＋ ３０℃〜Ａ
ｃａの温度域が３５０〜５００℃のベイナイト変態域へ
の冷却途中でオーステナイトのパーライト変態を抑止す
る目的で添加している。この目的のためには最低０．２
０％が必要である。一方、Ｍｎはオーステナイト安定化
元素であるとともに炭化物形成元素でもあり、Ｃとの親
和力はＦｅよりも強い、 Ｍｎ含有量が１．５０％を超
えるとベイナイトに含まれる炭化物量が多くなり、その
結果として残留オーステナイトへのＣの濃化が抑制され
るので、 Ｍｎ含有量の上限を１．５０％とした。Mn is generally an austenite stabilizing element.
Ac is known as an element that has the effect of lowering the transformation point, but in the present invention, Ac1+ 30℃~A
It is added for the purpose of suppressing the pearlite transformation of austenite during cooling to the bainite transformation region where the temperature range of ca is 350 to 500°C. For this purpose a minimum of 0.2
0% is required. On the other hand, Mn is an austenite-stabilizing element and also a carbide-forming element, and has a stronger affinity with C than Fe. When the Mn content exceeds 1.50%, the amount of carbides contained in bainite increases, resulting in Since this suppresses the concentration of C in retained austenite, the upper limit of the Mn content was set at 1.50%.
Ｎｉはオーステナイト安定化元素であり、３５０〜５０
０℃の温度域でのベイナイト変態において炭化物の形成
を抑制し、未変態オーステナイトへのＣの濃化を促進す
ることにより、残留オーステナイトの安定化に効果のあ
る元素であるＩＩＮＩ含有量が０．２％未満ではその効
果は十分ではなく、一方、１．０％を超えてもその効果
は飽和するのみならず。Ni is an austenite stabilizing element and has a content of 350 to 50
The IINI content, which is an element effective in stabilizing retained austenite, suppresses the formation of carbides during bainite transformation in the temperature range of 0°C and promotes the concentration of C in untransformed austenite. If it is less than 2%, the effect is not sufficient, while if it exceeds 1.0%, the effect not only becomes saturated.
いたずらに製造コストの上昇を招くのみである。This will only unnecessarily increase manufacturing costs.
本発明鋼板の化学成分組成は上記のＣ，Ｓｉ、 Ｍｎ。The chemical composition of the steel sheet of the present invention is the above-mentioned C, Si, and Mn.
Ｎｉ以外はＦａおよび不可避的不純物からなる。不可避
的不純物としては脱酸元素としてのＡｌ：０．１０％以
下の他にＰ、 Ｓ、 Ｎ、Ｃｕ、Ｃｒ、 Ｎｉなど一般
に鋼中に不可避的に混入する不純物が含まれる。The elements other than Ni consist of Fa and inevitable impurities. In addition to Al as a deoxidizing element: 0.10% or less, unavoidable impurities include impurities that are generally unavoidably mixed into steel, such as P, S, N, Cu, Cr, and Ni.
次に製造工程上の限定理由について述べる。Next, we will discuss the reasons for limitations in the manufacturing process.
まず、ａＩ板はＡｃ、＋３０℃〜ＡＣ３の温度域Ｃｒ、
温度）に３０ｓｅｃ〜１５ｍｉｎ（ｔ１時間）加熱保持
される。この条件は、フェライト基質中にオーステナイ
トを生成させ、オーステナイトにＣを濃化させるための
条件である。ここで生成されたオーステナイトは引き続
き行なわれるベイナイト変態域への急冷−保持により、
ベイナイトの生成に伴いさらに高Ｃ濃度のオーステナイ
トが生成されるのである。First, the aI plate is Ac, +30℃~AC3 temperature range Cr,
temperature) for 30 seconds to 15 minutes (t1 time). These conditions are conditions for producing austenite in the ferrite matrix and enriching the austenite with C. The austenite produced here is then rapidly cooled and retained in the bainite transformation region,
Along with the production of bainite, austenite with an even higher C concentration is produced.
オーステナイトを生成させるためには、 Ａｃ工以上の
加熱温度が必要であることは言うまでもないが、Ａｃ１
＋ ３０℃未満の温度範囲では生成されるオーステナイ
トの量が少なく、目的とするＴＲＩＰ効果を得るには不
足である。またＡｃ、を超えて加熱するとオーステナイ
ト量が多くなり過ぎてオーステナイトのＣ濃度が低くな
ってしまう。It goes without saying that in order to generate austenite, a heating temperature higher than that of Ac is required;
In a temperature range below +30°C, the amount of austenite produced is small and insufficient to obtain the desired TRIP effect. In addition, when heated above Ac, the amount of austenite becomes too large and the C concentration of austenite becomes low.
また保持時間が３０ｓｅｃ未満であると炭化物の溶解が
不十分であり、最終的に十分な量の残留オーステナイト
を確保することが困難である。一方。Further, if the holding time is less than 30 seconds, dissolution of carbides is insufficient, and it is difficult to finally secure a sufficient amount of retained austenite. on the other hand.
１５ｍｉｎを超えて保持しても格別の効果を期待できる
訳ではなく、いたずらにエネルギーを浪費するのみであ
る。Even if it is held for more than 15 minutes, no particular effect can be expected, and it will only waste energy unnecessarily.
次にＡｃ１＋ ３０℃〜Ａｃ、の温度域から３５０〜５
００℃のベイナイト変態域への冷却速度として１０℃八
ｅへ〜５００℃／５ｅｅ（Ｖ□速度）の範囲で急冷され
る。この急冷処理は６００℃付近でのパーライト変態を
抑止する目的で行なうものであり１本発明鋼の成分範囲
では最低１０℃／ｓｅｃ以上の冷却速度が必要である。Next, from the temperature range of Ac1+ 30℃~Ac, 350~5
The cooling rate to the bainite transformation region of 00°C is rapidly cooled in the range of 10°C to 5ee to 500°C/5ee (V□ rate). This rapid cooling treatment is performed for the purpose of suppressing pearlite transformation at around 600°C, and within the composition range of the steel of the present invention, a cooling rate of at least 10°C/sec is required.
５００℃／ｓｅｃを越える冷却速度としても何らさしつ
かえないが、現実に５００℃／ｓｅｃを越える冷却は困
難であり、製造設備上のコストが上昇するのみであるの
で、上限を５００℃７ｓｅｃとした。Although there is no problem with cooling rates exceeding 500° C./sec, in reality cooling exceeding 500° C./sec is difficult and only increases the cost of manufacturing equipment, so the upper limit was set at 500° C. 7 seconds.
引き続いて３５０〜５００℃の温度域（Ｔ２温度）に３
０ｓｅｃ〜３０ｍｉｎ （ｔｉ待時間保持される。この
温度域においてオーステナイトのベイナイト変態に伴い
、未変態オーステナイトへのＣの濃縮が起きるのである
。3 in the temperature range of 350-500℃ (T2 temperature)
A waiting time of 0 sec to 30 min (ti) is maintained. In this temperature range, C is concentrated into untransformed austenite as austenite transforms into bainite.
未変態オーステナイトへのＣの濃縮はいわゆる上部ベイ
ナイトの場合に顕著であり、下部ベイナイトではその効
果は期待できない、３５０℃未満の温度域まで冷却し保
持すると、下部ベイナイトが生成するため未変態オース
テナイトへのＣの濃縮は不足となるばかりでなく、マル
テンサイトの生成量が増加するため、鋼の強度は上昇す
るものの延性が著しく低下してしまう、５００℃を越え
る温度域に保持するとベイナイトの変態速度が速いため
残留オーステナイト量の調整が困難となるばかりか、パ
ーライトの生成をも招き、目的とするフェライト＋ベイ
ナイト＋残留オーステナイトの組織を得ることが困難で
ある。The concentration of C in untransformed austenite is remarkable in the case of so-called upper bainite, and this effect cannot be expected in lower bainite.When cooled to a temperature range below 350°C and held, lower bainite is generated, so it changes to untransformed austenite. Not only is the enrichment of C insufficient, but also the amount of martensite generated increases, so although the strength of the steel increases, the ductility decreases significantly.If the temperature is kept in a temperature range exceeding 500℃, the transformation rate of bainite decreases. Because of the rapid rate of change, it is not only difficult to adjust the amount of retained austenite, but also leads to the formation of pearlite, making it difficult to obtain the desired structure of ferrite + bainite + retained austenite.
３５０〜５００℃の温度域で１０％以上の残留オーステ
ナイトを生成するためには、保持時間は最低３０ｓｅｃ
は必要である。保持時間が３０ｓｅｃ未満の場合にはベ
イナイト変態の進行が不十分であり未変態オーステナイ
トのほとんどは引き続き行なわれる室温への冷却途中で
マルテンサイトに変態してしまい、鋼の強度は上昇する
ものの延性は著しく低下してしまう。In order to generate 10% or more retained austenite in the temperature range of 350 to 500°C, the holding time must be at least 30 seconds.
is necessary. If the holding time is less than 30 seconds, the progress of bainite transformation is insufficient and most of the untransformed austenite transforms into martensite during subsequent cooling to room temperature, and although the strength of the steel increases, its ductility decreases. It will drop significantly.
保持時間が３０ｍｉｎを越えるとベイナイト変態が進み
すぎ、残留オーステナイトをｌＯ％以上得ることが困難
となる。When the holding time exceeds 30 min, bainite transformation progresses too much, making it difficult to obtain retained austenite of 10% or more.
次に３５０〜５００℃のベイナイト変態域から室温へは
５℃八へｃ以上の冷却速度（Ｖａ速度）で冷却すれば良
い、１℃八へｅ未満の徐冷を行なうとベイナイト変態が
さらに進行し、残留オーステナイト量の減少を招いてし
まう、この冷却は空冷でも水冷でも良く、冷却速度の上
限はとくに定めない。Next, from the bainitic transformation region of 350 to 500°C to room temperature, it is sufficient to cool at a cooling rate (Va rate) of 5°C or higher.If slow cooling is performed at a rate of less than 1°C, the bainite transformation will progress further. However, this cooling, which causes a decrease in the amount of retained austenite, may be performed by air cooling or water cooling, and there is no particular upper limit to the cooling rate.
上記のようにして得ら九た網板はフェライト。The net plate obtained as described above is made of ferrite.
ベイナイト、残留オーステナイトの３相からなり。It consists of three phases: bainite and retained austenite.
残留オーステナイトを少くとも１０％以上含む複合組織
鋼である。またマルテンサイトは最高１０％までは含有
することを許容できる。It is a composite structure steel containing at least 10% retained austenite. Further, it is permissible to contain martensite at a maximum of 10%.
（発明の具体的開示）
以下実施例により本発明の効果をさら１こ具体的に説明
する。(Specific Disclosure of the Invention) The effects of the present invention will be explained in more detail with reference to Examples below.
実施例
第１表に示す化学成分の鋼を常法によって溶製鋳造し、
常法により熱延、冷延して得られる１、０ｍ鵬厚の鋼板
を第２表の条件で熱処理し、これから、ＬＩＳ Ｓ号引
張試験片を採取し、引張速度１０ｉ＋ｍ／＋ｉｎで試験
を行ない、 ＴＳ、ＥｌおよびＴＳＸＥＩの値を調べた
。Example Steel having the chemical composition shown in Table 1 was melted and cast by a conventional method,
A steel plate with a thickness of 1.0 m obtained by hot-rolling and cold-rolling by a conventional method was heat-treated under the conditions shown in Table 2, and from this, LISS No. S tensile test specimens were taken and tested at a tensile speed of 10 m/+ in. , TS, El and TSXEI values were investigated.
第３表に見られるように本発明モある試料Ｎ１１ｌ〜６
はいずれもＴＳが６０ｋｇｆ／＋＋ｖ＋”〜９０ｋｇｆ
／ｍｏ＋”級の高強度ながらＥｌは２５％以上と優れた
延性を示し、ＴＳＸＥＩ値はいずれも２，０００以上と
強度延性バランスに優れていることが明らかである。As seen in Table 3, samples N11l to 6 according to the present invention
In both cases, the TS is 60kgf/++v+”~90kgf
/mo+'' grade, but exhibits excellent ductility with an El of 25% or more, and all TSXEI values are 2,000 or more, clearly showing an excellent strength-ductility balance.
これに対して試料Ｎα７〜２３は本発明範囲外の例であ
る。まず、試料Ｎ１１７〜１０は本発明の鋼成分範囲外
の鋼に本発明の熱処理条件により製造したもノテある。On the other hand, samples Nα7 to Nα23 are examples outside the scope of the present invention. First, samples N117 to 10 were produced using steels outside the steel composition range of the present invention under the heat treatment conditions of the present invention.
試料＆７，９．１０はＴＳ Ｘ Ｅｌ値がいずれも２，
０００未満であり強度延性バランスに劣るといえる。試
料＆８は丁Ｓが１０５に、ｆ／■■３傘比較例
Ｔ、 ： Ａｃ、 ＋ ３０℃〜Ａｃ、の焼鈍温度ｔ□
：Ｔ、における保持時間
Ｖｉ： Ｔ、よりの冷却速度
Ｔ、 ： ３５０〜５００℃のベイナイト変態処理温度
ｂ：Ｔｚにおける保持時間
ｖ２：その後の冷却速度
でＥｌが２８％であり、ＴＳＸＥＩ値も２９４０と優れ
た強度延性バランスを示すが、ｉｌＦのＣ含有量は０．
３５％と高く溶接性に劣る欠点を有している。Samples &7 and 9.10 both have TS X El values of 2,
It can be said that the strength and ductility balance is poor. For sample &8, S is 105, f/■■3 umbrella comparative example T: Ac, +30℃~Ac, annealing temperature t□
: Holding time at T, Vi: Cooling rate T at T, : Bainite transformation treatment temperature of 350 to 500°C b: Holding time at Tz v2: At the subsequent cooling rate, El is 28%, and the TSXEI value is also 2940. However, the C content of ilF is 0.
It has a drawback of poor weldability, which is as high as 35%.
試料＆１１は本発明の範囲の組成の鋼に本発明の熱処理
条件と異なる熱処理を適用したものであるが、ＴＳＸＥ
ｌ値は２０ｑＯに満たない。Sample &11 is a steel having a composition within the range of the present invention and subjected to heat treatment different from the heat treatment conditions of the present invention, but TSXE
The l value is less than 20qO.
試料Ｎａ１２〜２３は本発明の鋼成分範囲内の鋼に本発
明の熱処理条件と異なる熱処理により製造したものであ
る。いずれも残留オーステナイト量は１０％未満であり
、組織因子としてパーライトやマルテンサイトの混在を
生じるものもある。いずれもＴＳ Ｘ Ｅｌ値は２００
０未満であり、強度延性バランスは劣ることが明らかで
ある。Samples Na12 to Na23 were produced by heat treating steel within the steel composition range of the present invention under heat treatment conditions different from those of the present invention. In all cases, the amount of retained austenite is less than 10%, and in some cases pearlite and martensite are mixed as a structural factor. In both cases, the TS X El value is 200.
It is clear that the strength-ductility balance is poor.
（発明の効果）
以上のように本発明によれば、ＴＳが６０ｋｇｆ／ｍｍ
”以上１００ｋｇｆ／ａｍ”未満の範囲で、ＴＳ Ｘ
Ｅｌ値が２０００を超え強度延性バランスに優れた高強
度鋼板の製造が可能である。(Effect of the invention) As described above, according to the present invention, the TS is 60 kgf/mm.
In the range of "more than 100 kgf/am", TS
It is possible to produce high-strength steel sheets with an El value exceeding 2000 and an excellent balance of strength and ductility.
（外１名）(1 other person)
Claims (2)
．００％、Ｍｎ：０．２０〜１．５０％を含み残部Ｆｅ
および不可避的不純物からなる鋼材を、Ａｃ＿１＋３０
℃〜Ａｃ＿３の温度域に加熱し３０ｓｅｃ〜１５ｍｉｎ
保持した後、３５０〜５００℃の温度域まで冷却速度１
０〜５００℃／ｓｅｃで冷却し、該温度域で３０ｓｅｃ
〜３０ｍｉｎ保持した後、室温まで冷却することにより
フェライトとベイナイトを主相としさらに１０％以上の
残留オーステナイトを含有することを特徴とする延性の
優れた高強度鋼板の製造方法。(1) C: 0.05-0.25%, Si: 1.00-3
．． 00%, Mn: 0.20-1.50%, balance Fe
Ac_1+30 steel material consisting of and unavoidable impurities
Heat to a temperature range of ℃~Ac_3 for 30sec~15min
After holding, cooling rate 1 to a temperature range of 350-500℃
Cool at 0 to 500°C/sec, and cool for 30sec in the temperature range
A method for producing a high-strength steel plate with excellent ductility, characterized in that the main phase is ferrite and bainite and further contains 10% or more of retained austenite by holding the plate for ~30 minutes and then cooling it to room temperature.
．００％、Ｍｎ：０．２０〜１．５０％、Ｎｉ：０．２
０％〜１．００％を含み、残部Ｆｅおよび不可避的不純
物からなる鋼材を、Ａｃ＿１＋３０℃〜Ａｃ＿３の温度
域に加熱し３０ｓｅｃ〜１５ｍｉｎ保持した後、３５０
〜５００℃の温度域まで冷却速度１０〜５００℃／ｓｅ
ｃで冷却し、該温度域で３０ｓｅｃ〜３０ｍｉｎ保持し
た後、室温まで冷却することによりフェライトとベイナ
イトを主相としさらに１０％以上の残留オーステナイト
を含有することを特徴とする延性の優れた高強度鋼板の
製造方法。(2) C: 0.05-0.25%, Si: 1.00-3
．． 00%, Mn: 0.20-1.50%, Ni: 0.2
A steel material containing 0% to 1.00% and the balance consisting of Fe and unavoidable impurities is heated to a temperature range of Ac_1+30°C to Ac_3 and held for 30 seconds to 15 minutes, then heated to 350°C.
Cooling rate 10-500℃/se to temperature range of ~500℃
After cooling at temperature c and holding in the temperature range for 30 seconds to 30 minutes, cooling to room temperature produces a high strength product with excellent ductility characterized by having ferrite and bainite as the main phases and further containing 10% or more of retained austenite. Method of manufacturing steel plates.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32727987A JPH01168819A (en) | 1987-12-25 | 1987-12-25 | Manufacture of steel plate with composite structure having high ductility and high strength |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32727987A JPH01168819A (en) | 1987-12-25 | 1987-12-25 | Manufacture of steel plate with composite structure having high ductility and high strength |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01168819A true JPH01168819A (en) | 1989-07-04 |
Family
ID=18197352
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32727987A Pending JPH01168819A (en) | 1987-12-25 | 1987-12-25 | Manufacture of steel plate with composite structure having high ductility and high strength |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01168819A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04341523A (en) * | 1991-05-17 | 1992-11-27 | Kobe Steel Ltd | Production of hot rolled high strength steel plate excellent in ductility and workability |
| EP0586704A1 (en) * | 1991-05-30 | 1994-03-16 | Nippon Steel Corporation | High-yield-ratio hot-rolled high-strength steel sheet excellent in formability or in both of formability and spot weldability, and production thereof |
| JP2003171736A (en) * | 2001-02-28 | 2003-06-20 | Kobe Steel Ltd | High strength steel sheet having excellent workability, and production method therefor |
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|---|---|---|---|---|
| JPS61157625A (en) * | 1984-12-29 | 1986-07-17 | Nippon Steel Corp | Manufacture of high-strength steel sheet |
| JPS624832A (en) * | 1985-06-28 | 1987-01-10 | Nippon Steel Corp | Production of high-carbon steel strip having excellent ductility |
| JPS62164828A (en) * | 1986-01-13 | 1987-07-21 | Kobe Steel Ltd | Production of high ductility high strength composite structure steel plate having excellent spot weldability |
| JPS62182224A (en) * | 1986-02-05 | 1987-08-10 | Nippon Steel Corp | Production of high-strength steel sheet having excellent ductility |
| JPS62188729A (en) * | 1986-02-13 | 1987-08-18 | Nippon Steel Corp | Manufacture of high strength steel superior in workability |
| JPS63241120A (en) * | 1987-02-06 | 1988-10-06 | Kobe Steel Ltd | Manufacture of high ductility and high strength steel sheet having composite structure |
| JPS6479322A (en) * | 1987-09-21 | 1989-03-24 | Kobe Steel Ltd | Production of composite structure high-strength cold rolled steel sheet having excellent bulging property and fatigue characteristic |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61157625A (en) * | 1984-12-29 | 1986-07-17 | Nippon Steel Corp | Manufacture of high-strength steel sheet |
| JPS624832A (en) * | 1985-06-28 | 1987-01-10 | Nippon Steel Corp | Production of high-carbon steel strip having excellent ductility |
| JPS62164828A (en) * | 1986-01-13 | 1987-07-21 | Kobe Steel Ltd | Production of high ductility high strength composite structure steel plate having excellent spot weldability |
| JPS62182224A (en) * | 1986-02-05 | 1987-08-10 | Nippon Steel Corp | Production of high-strength steel sheet having excellent ductility |
| JPS62188729A (en) * | 1986-02-13 | 1987-08-18 | Nippon Steel Corp | Manufacture of high strength steel superior in workability |
| JPS63241120A (en) * | 1987-02-06 | 1988-10-06 | Kobe Steel Ltd | Manufacture of high ductility and high strength steel sheet having composite structure |
| JPS6479322A (en) * | 1987-09-21 | 1989-03-24 | Kobe Steel Ltd | Production of composite structure high-strength cold rolled steel sheet having excellent bulging property and fatigue characteristic |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04341523A (en) * | 1991-05-17 | 1992-11-27 | Kobe Steel Ltd | Production of hot rolled high strength steel plate excellent in ductility and workability |
| EP0586704A1 (en) * | 1991-05-30 | 1994-03-16 | Nippon Steel Corporation | High-yield-ratio hot-rolled high-strength steel sheet excellent in formability or in both of formability and spot weldability, and production thereof |
| EP0586704A4 (en) * | 1991-05-30 | 1995-10-18 | Nippon Steel Corp | High-yield-ratio hot-rolled high-strength steel sheet excellent in formability or in both of formability and spot weldability, and production thereof |
| US5505796A (en) * | 1991-05-30 | 1996-04-09 | Nippon Steel Corporation | High yield ratio-type, hot rolled high strength steel sheet excellent in formability or in both of formability and spot weldability, and production thereof |
| EP0881308A1 (en) * | 1991-05-30 | 1998-12-02 | Nippon Steel Corporation | High yield ratio-type, hot rolled high strenght steel sheet excellent in formability or and spot weldability |
| JP2003171736A (en) * | 2001-02-28 | 2003-06-20 | Kobe Steel Ltd | High strength steel sheet having excellent workability, and production method therefor |
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