JPH03291356A - Steel having excellent toughness in weld heat affected zone - Google Patents
Steel having excellent toughness in weld heat affected zoneInfo
- Publication number
- JPH03291356A JPH03291356A JP9187690A JP9187690A JPH03291356A JP H03291356 A JPH03291356 A JP H03291356A JP 9187690 A JP9187690 A JP 9187690A JP 9187690 A JP9187690 A JP 9187690A JP H03291356 A JPH03291356 A JP H03291356A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- ppm
- toughness
- added
- affected zone
- 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 59
- 239000010959 steel Substances 0.000 title claims abstract description 59
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 18
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 16
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 10
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 10
- 229910000975 Carbon steel Inorganic materials 0.000 claims abstract description 7
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 7
- 239000010962 carbon steel Substances 0.000 claims abstract description 7
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 5
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 5
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 5
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 4
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 4
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 3
- 239000000463 material Substances 0.000 claims description 22
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 13
- 229910052760 oxygen Inorganic materials 0.000 claims description 13
- 239000001301 oxygen Substances 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims 1
- 229910052802 copper Inorganic materials 0.000 abstract description 3
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 10
- 229910000859 α-Fe Inorganic materials 0.000 description 5
- 229910000532 Deoxidized steel Inorganic materials 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000009749 continuous casting Methods 0.000 description 4
- 238000005336 cracking Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000003466 welding Methods 0.000 description 4
- 239000010953 base metal Substances 0.000 description 3
- 239000002131 composite material Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 2
- 229910052681 coesite Inorganic materials 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 229910052906 cristobalite Inorganic materials 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 229910052682 stishovite Inorganic materials 0.000 description 2
- 150000003568 thioethers Chemical class 0.000 description 2
- 229910052905 tridymite Inorganic materials 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910000746 Structural steel Inorganic materials 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000009533 lab test Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000008689 nuclear function Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は厚板、鋼管等溶接構造用鋼材であって、溶接熱
影響部にすぐれた靭性を有する鋼材に関するものである
。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a steel material for welded structures such as thick plates and steel pipes, and which has excellent toughness in the weld heat affected zone.
（従来の技術）
大型構造用鋼など溶接接合される鋼材は、溶接熱影響部
において鋼材の製造過程で与えられる特性を維持するこ
とは、−船釣に困難である。すなわち、溶接入熱によっ
て熱影響部（以下ＨＡＺという）の結晶粒が粗大になり
組織が脆化する。つまり、ＨＡＺの結晶粒サイズは鋼の
低温靭性に大きな影響を与えることが知られており、そ
のためＨＡＺ組織を微細化する多くの技術が開発され実
用化されている。(Prior Art) For steel materials to be welded, such as large structural steel, it is difficult for boat fishing to maintain the characteristics imparted during the manufacturing process of the steel materials in the weld heat affected zone. That is, due to welding heat input, the crystal grains in the heat affected zone (hereinafter referred to as HAZ) become coarse and the structure becomes brittle. In other words, it is known that the grain size of the HAZ has a large effect on the low-temperature toughness of steel, and therefore many techniques for refining the HAZ structure have been developed and put into practical use.
例えば特開昭６１−７９７４５号公報に開示されている
ように、鋼中にＴｉを添加し、オーステナイト結晶粒内
に微細なＴｉ酸化物を分散させ、これを変態核として粒
内フェライトプレートを発達させることによりＨＡＺ組
織の微細化を図る技術を提案している。また特開昭６１
−２３８９４０号公報には２次脱酸生成物としてＴｉを
添加し微細Ｔｉ酸化物を均一分散させることによってＨ
Ａ２靭性が改善できることを開示している。For example, as disclosed in JP-A-61-79745, Ti is added to steel, fine Ti oxides are dispersed within austenite grains, and intragranular ferrite plates are developed using these as transformation nuclei. We are proposing a technology to refine the HAZ structure by Also, JP-A-61
-238940 discloses that by adding Ti as a secondary deoxidation product and uniformly dispersing fine Ti oxides, H
It is disclosed that A2 toughness can be improved.
（発明が解決しようとする課題）
上述したＴｉ添加鋼はＨＡＺ靭性を改良する効果はある
が、連続鋳造によって製造した鋼材ではその中心部にお
ける酸化物の生成量が比較的少なく、そのために入熱量
の大きい溶接の場合には、低温での高い靭性をＨＡＺに
得ることが難しいという問題点がある。(Problem to be solved by the invention) Although the above-mentioned Ti-added steel has the effect of improving HAZ toughness, the amount of oxide produced in the center of the steel material manufactured by continuous casting is relatively small, and therefore the heat input is low. In the case of welding where the welding temperature is large, there is a problem in that it is difficult to obtain high toughness in the HAZ at low temperatures.
一方本発明者らは、Ｔｉの他にＺｒ等の脱酸元素を溶鋼
中に添加し、鋼中に微細な酸化物を分散させて鋼組織を
微細化させる方法を提案している。On the other hand, the present inventors have proposed a method in which a deoxidizing element such as Zr is added to molten steel in addition to Ti, and fine oxides are dispersed in the steel to refine the steel structure.
（特開平１−２２８６４３号公報参照）本発明は、上記
問題点を改善すると共に、前記Ｚｒ添加による鋼中酸化
物を微細分散させる技術を利用し、Ｔｉ添加と共にこれ
らの含有量を調整することにより酸化物の個数を増加さ
せてより一層ＨＡＺ靭性を向上する鋼材を提供すること
を目的とするものである。(Refer to Japanese Unexamined Patent Publication No. 1-228643) The present invention improves the above-mentioned problems and utilizes the technique of finely dispersing oxides in steel due to the addition of Zr, and adjusts the content of these in addition to Ti addition. The object of the present invention is to provide a steel material that further improves HAZ toughness by increasing the number of oxides.
（課題を解決するための手段）
本発明は上記目的を達成するために、以下の構成を要旨
とする。(Means for Solving the Problems) In order to achieve the above object, the present invention has the following configuration as a gist.
すなわち、
（１）重量％としてＭｎ ： ０．３〜２．２％、Ｓｉ
：０．０２〜０．５％を含有し、かつＡｌを０．００８
％以下にした組成を有する炭素鋼材に、ＴｉとＺｒを添
加し、ＴｉとＺｒの濃度を下記式の範囲内としたことを
特徴とする溶接熱影響部靭性の優れた鋼材。That is, (1) Mn: 0.3 to 2.2% as weight%, Si
: Contains 0.02-0.5% and 0.008% Al
A steel material with excellent weld heat-affected zone toughness, characterized in that Ti and Zr are added to a carbon steel material having a composition of % or less, and the concentrations of Ti and Zr are within the range of the following formula.
０．４ｘ （Ｃ，（０）−Ｃ２（Ｏ）） ≦Ｃ（Ｚｒ）
＋Ｃ（Ｔｉ）≦３Ｘ （Ｃ，（０）−Ｃ，（０））かっ
Ｃ（Ｚｒ）≧５０（ｐｐ＠）
ここでＣ（Ｚｒ）；Ｚｒ濃度（ｐｐｍ）Ｃ（Ｔｉ）；Ｔ
ｉ濃度（ｐｐｍ）
Ｃ＋ （０）；Ｍｎ及びＳｉを添加する前の溶鋼中酸
素濃度（ｐｐｍ）
Ｃ２（Ｏ）；Ｍｎ及びＳｉ１必要に応じてＡｌを添加し
た後の溶鋼
中酸素濃度（ｐｐｍ）
（２）重量％として、Ｃ：≦０，２％、Ｍｎ：０．３〜
２，２％、Ｓｉ：０．０２〜０，５％かつＡＪ：０．０
０８％以下を含有する炭素鋼材に
Ｃｕ ： ０．０５〜１．００％、
Ｎｉ：０．０５〜４．０％、
Ｃｒ ： ０．０５〜１．０％、
Ｍ ｏ ： ０．０５−０．４％、
Ｎ ｂ ： ０．００３〜００６０％、Ｖ ：０．０
０５〜０．０８０％、
Ｂ ：０．０００３〜０．００２０％、Ｃａ ： ０
．００１〜０．００５％、の１種又は２種以上を含有し
、更に、Ｔ１とＺｒとを下記式で示す濃度範囲で添加し
たことを特徴とする溶接熱影響部靭性の優れた鋼材。0.4x (C, (0)-C2(O)) ≦C(Zr)
+C(Ti)≦3X (C, (0)-C, (0)) C(Zr)≧50(pp@) where C(Zr); Zr concentration (ppm) C(Ti); T
i concentration (ppm) C+ (0); Oxygen concentration in molten steel before adding Mn and Si (ppm) C2 (O); Oxygen concentration in molten steel after adding Mn and Si1 as necessary (ppm) (2) As weight%, C: ≦0.2%, Mn: 0.3~
2.2%, Si: 0.02-0.5% and AJ: 0.0
Carbon steel material containing 0.08% or less Cu: 0.05-1.00%, Ni: 0.05-4.0%, Cr: 0.05-1.0%, Mo: 0.05-0 .4%, Nb: 0.003-0060%, V: 0.0
05-0.080%, B: 0.0003-0.0020%, Ca: 0
．． A steel material having excellent weld heat-affected zone toughness, characterized in that it contains one or more of the following:
０．４Ｘ （Ｃ，（０）−Ｃ２（Ｏ）｝≦Ｃ＋Ｃ（Ｔｉ
）；ｉ；３ｘ （Ｃ＋ （０）−Ｃ２（Ｚｒ）
（０））
かっＣ（Ｚｒ）≧５０（ｐｐｍ）
ここでＣ（Ｚｒ）；Ｚｒ濃度（ｐｐｍ）Ｃ（Ｔｉ）；Ｔ
ｉ濃度（ｐｐｍ）
Ｃ＋ （０）；Ｍｎ及びＳｉを添加する前の溶鋼中酸
素濃度（ｐｐｍ）
Ｃ２（Ｏ）；Ｍｎ及びＳｉ、必要に応じてＡｌを添加し
た後の溶鋼
中酸素濃度（ｐｐｍ）
以下本発明の詳細な説明する。0.4X (C, (0)-C2(O)}≦C+C(Ti
);i;3x (C+ (0)-C2(Zr) (0)) C(Zr)≧50(ppm) where C(Zr);Zr concentration (ppm)C(Ti);T
i concentration (ppm) C+ (0); Oxygen concentration in molten steel before adding Mn and Si (ppm) C2(O); Oxygen concentration in molten steel after adding Mn and Si, and if necessary Al (ppm) ) The present invention will be described in detail below.
本発明の対象とする鋼材はＣ：０．２０％以下を含む炭
素鋼であり、この鋼材のＨＡＺ靭性を向上させるために
は、鋼の化学成分の適性化と、これによる結晶粒の微細
化が必要である。The steel material targeted by the present invention is a carbon steel containing C: 0.20% or less, and in order to improve the HAZ toughness of this steel material, it is necessary to optimize the chemical composition of the steel and thereby refine the crystal grains. is necessary.
本願発明は、Ｍｎが（１３〜２．２％、かつＳｉが０．
０２〜０．５％の範囲にあり、かつＡｌをｏ、 ｏｏｓ
％以下に低減し、必要に応じてＣｕ、Ｎｉ％Ｃｒ。In the present invention, Mn is (13 to 2.2%) and Si is 0.
02~0.5%, and Al is o, oos
% or less, and Cu, Ni%Cr as necessary.
ＭＯｌＶ、ＢおよびＣａの少くとも１種を含む炭素鋼で
あり、更にＴｉおよびＺｒをそれぞれ５０ｐｐｍ以上複
合添加するものであって、このような成分を含む鋼材は
厚板並びに鋼管向けの多くの鋼種に適用できる。It is a carbon steel containing at least one of MOLV, B, and Ca, and further contains 50 ppm or more of each of Ti and Zr, and steel materials containing such components are used in many steel types for thick plates and steel pipes. Applicable to
前記したようにＴｉを添加して脱酸し、ＨＡＺに微細な
フェライトを生成させて靭性を向上することは公知であ
るが、Ｔｉ脱酸鋼の場合、ＨＡＺに微細フェライトが生
成するのはＴｉ酸化物上に析出したＭｎＳが大きな役割
を果たしていると言われている。すなわち、鋼中に分散
させた介在物を変態核として、オーステナイト粒内から
微細なフェライト（Ｉｎｔｒａｇｒａｎｕｌａｒ Ｆｅ
ｒｒｉｔｅ Ｐｌａｔｅ−ＩＦＰという）を生成させる
ことが組織を微細化するのであるが、この介在物が、Ｍ
ｎ、Ｓｉの脱酸複合酸化物（Ｍｎ−シリケート）の上に
析出するＭｎＳであり、微細均一に分散したＭｎＳはど
ＩＦＰ変態核機能に基づく組織の、より微細化に役立つ
。Ｔｉは、上記Ｍｎ−シリケー゛トに作用しくＭｎＯ，
ＳｉＯ２、Ｔｉｏ２複合物となり）それを微細にし、結
果的にＭｎＳの析出を細くできるのであるが、鋳片厚み
方向中心部での生成量が少く、これを増加させるために
は、単に酸化物そのものが鋼中に多数分散し易いだけで
なく、その酸化物上にＭｎＳが析出しやすい脱酸条件を
選択する必要がある。As mentioned above, it is known that Ti is added to deoxidize to generate fine ferrite in the HAZ to improve toughness, but in the case of Ti-deoxidized steel, fine ferrite is generated in the HAZ due to Ti. It is said that MnS deposited on the oxide plays a major role. In other words, fine ferrite (intragranular Fe) is produced from within the austenite grains using inclusions dispersed in the steel as transformation nuclei.
The formation of microstructures (rrite plate-IFP) refines the structure, but these inclusions
This is MnS precipitated on a deoxidized composite oxide (Mn-silicate) of n, Si, and the finely and uniformly dispersed MnS helps to further refine the structure based on the IFP transformation nucleus function. Ti acts on the above Mn-silicate, and MnO,
(SiO2, Tio2 composite) can be made fine, and as a result, the MnS precipitation can be made thinner. However, the amount formed at the center of the thickness of the slab is small, and in order to increase this, it is necessary to simply remove the oxide itself. It is necessary to select deoxidizing conditions that not only make it easy for MnS to be dispersed in large numbers in the steel, but also make it easy for MnS to precipitate on the oxide.
本発明はＴｉと共にＺｒを添加するのであるが、Ｚｒに
よる脱酸は多数の微細な酸化物を鋼中に分散させるのに
効果的であることが、本発明者の研究結果から確認され
ている。すなわち、第１表に示す成分の鋼を実際の製造
工程で溶製し、連続鋳造で鋳片を製造して、Ｚｒ添加効
果の下限値を知る目的を含めて２水準のＺｒ添加量とし
、従来のＴｉ添加脱酸鋼の場合と比較した。これらのサ
ンプルにおける鋳片厚み方向における酸化物個数の関係
を第２図に示したが、Ｔｉ単独添加鋼に比して、Ｔｉと
共にＺｒを添加した連鋳材はその厚み中心部の酸化物個
数が増加し、特にＺｒを５０ｐｐｍ以上添加した場合は
その増加が著しいことが明らかである。そして第３図に
みられるように、この酸化物上へ十分な量のＭｎＳが析
出し、溶接後の調査でも溶接熱影響部の組織微細化と低
温靭性の向上が確認できた。In the present invention, Zr is added together with Ti, and the inventor's research results have confirmed that deoxidation with Zr is effective in dispersing many fine oxides in steel. . That is, steel with the components shown in Table 1 was melted in the actual manufacturing process, slabs were manufactured by continuous casting, and two levels of Zr addition were made, including the purpose of determining the lower limit of the Zr addition effect. A comparison was made with the case of conventional Ti-added deoxidized steel. The relationship between the number of oxides in the thickness direction of the slab in these samples is shown in Figure 2. Compared to the steel with only Ti added, the continuous casting material in which Zr is added together with Ti has a lower number of oxides in the center of the thickness. It is clear that the increase is particularly significant when 50 ppm or more of Zr is added. As shown in FIG. 3, a sufficient amount of MnS was precipitated on this oxide, and post-weld examination also confirmed that the structure of the weld heat-affected zone was refined and the low-temperature toughness was improved.
このようにＺｒ脱酸は多数の微細な酸化物個数を鋼中に
分散させるに顕著な効果があるがＭｎＳはＺｒ酸化物よ
りＴｉ酸化物、そしてそれ以上にＭｎ−シリケートに析
出しやすい。Ｍｎ−シリケートは、溶鋼にＭｎとＳｉを
添加した時に生成するが、その後ＴｉやＺｒを添加する
とこれらの元素に還元され、特にＴｉ５Ｚｒを過剰に添
加するとＭｎ−シリケートは消失してしまう。従って、
Ｔｉ脱酸鋼にＺｒを添加する場合には、このＭｎ−シリ
ケートをすべて還元してしまわないように添加量を制限
する必要がある。これはＭｎとＳｉの量や脱酸時の溶鋼
酸素濃度に依存するものであり、熱力学計算と第１表に
示すような鋼の成分で行なった実験室での試験結果から
、以下の条件を得た。As described above, Zr deoxidation has a remarkable effect on dispersing a large number of fine oxides in steel, but MnS is more likely to precipitate in Ti oxide than Zr oxide, and even more so in Mn-silicate. Mn-silicate is generated when Mn and Si are added to molten steel, but when Ti or Zr is subsequently added, it is reduced to these elements, and especially when Ti5Zr is added in excess, Mn-silicate disappears. Therefore,
When adding Zr to Ti-deoxidized steel, it is necessary to limit the amount added so as not to reduce all of this Mn-silicate. This depends on the amount of Mn and Si and the molten steel oxygen concentration during deoxidation. Based on thermodynamic calculations and laboratory test results conducted with the steel composition shown in Table 1, the following conditions are determined. I got it.
０．４Ｘ （Ｃ，（０）−Ｃ，（０）） ≦Ｃ十Ｃ（
Ｔｉ）≦３ｘ （Ｃ，（０）−ｃ２ここでＣ（Ｚｒ）：
Ｚｒ濃度（ｐｐｍ）Ｃ（Ｔｉ）；Ｔｉ濃度（ｐｐｍ）
Ｃ＋ （０）；Ｍｎ及びＳｉを添加する前の溶鋼中酸
素濃度（ｐｐｍ）
（Ｚｒ）
（○））
Ｃ２（Ｏ）；Ｍｎ及びＳｉ、必要に応じてＡｎを添加し
た後の溶鋼
中酸素濃度（ｐｐＭｌ）
この条件をもとに確認試験を、第２表に示すような鋼の
成分で、実際の製造工程で行なった結果、第２図に示す
ように連鋳片の厚み方向中心部の酸化物個数が増加し、
しかも第３図に示すように、これらの酸化物上に多数の
ＭｎＳが析出した。更に溶接後の調査でもＨＡＺ部に微
細なＩＦＰが生成し、低温靭性が向上した。0.4X (C, (0)-C, (0)) ≦C0C(
Ti)≦3x (C, (0)-c2 where C(Zr):
Zr concentration (ppm) C (Ti); Ti concentration (ppm) C+ (0); Oxygen concentration in molten steel (ppm) before adding Mn and Si (Zr) (○)) C2 (O); Mn and Si , Oxygen concentration in molten steel after adding An as necessary (ppMl) Based on these conditions, a confirmation test was conducted in the actual manufacturing process with the steel components shown in Table 2. As shown in Figure 2, the number of oxides in the center of the continuous slab in the thickness direction increases,
Moreover, as shown in FIG. 3, a large number of MnS were precipitated on these oxides. Furthermore, post-weld inspection also showed that fine IFP was generated in the HAZ, and the low-temperature toughness was improved.
更に本試験により、Ｚｒ添加による酸化物個数増加の効
果は、Ｚｒ添加量が５０ｐｐｍ以上で現れることが判っ
た。Furthermore, this test revealed that the effect of increasing the number of oxides by adding Zr appears when the amount of Zr added is 50 ppm or more.
以下に本発明鋼において、その含有成分を限定した理由
を述べる。The reasons for limiting the contained components in the steel of the present invention will be described below.
本発明は溶接構造用炭素でありＣは０．２％まで含有す
る。すなわちＣは強度を向上させるために有効な元素で
あり、通常０．２％まで含有する。これ以上の添加は溶
接性、ＨＡＺ靭性を劣化する。The present invention is carbon for welding structures, and contains up to 0.2% of C. That is, C is an effective element for improving strength, and is usually contained up to 0.2%. Addition of more than this will deteriorate weldability and HAZ toughness.
鋼中に通常混入するＰは、ミクロ偏析により溶接割れを
起すので、これを防止するために０．０１５％を越えな
いようできるだけ低減する必要がある。P, which is normally mixed in steel, causes weld cracking due to microsegregation, so in order to prevent this, it is necessary to reduce it as much as possible so as not to exceed 0.015%.
また、Ｓは多くなると粗大硫化物系介在物ができ、母材
靭性を低下させ、ＨＡＺ靭性を劣化させる。Moreover, when S increases, coarse sulfide-based inclusions are formed, which lowers the toughness of the base material and deteriorates the HAZ toughness.
そのため、０．０１０％以下とする。Therefore, it is set to 0.010% or less.
Ｓｉは母材強度を確保し、脱酸生成物の形成に必要な元
素である。本発明ではＭｎ０−３ｉｆｔの複合酸化物を
形成し、組織の微細化に役立つ。Si is an element that ensures the strength of the base material and is necessary for the formation of deoxidized products. In the present invention, a composite oxide of Mn0-3ift is formed, which is useful for microstructuring.
そのために０．０２％以上含有させる。しかし過剰の添
加はＨＡＺ靭性を劣化させるので、０．５％を上限とす
る。Therefore, it is contained at 0.02% or more. However, since excessive addition deteriorates HAZ toughness, the upper limit is set at 0.5%.
Ｍｎは母材の強度靭性を確保するために０．３％以上の
添加が必要である。またＳｉと共に脱酸生成物及び硫化
物を生成し、母材及びＨＡＺ組織を微細化し靭性を向上
させる。しかし多量に添加すると溶接性、ＨＡＺ靭性を
劣化させるので、２．２％以下とする。Mn needs to be added in an amount of 0.3% or more to ensure the strength and toughness of the base material. It also generates deoxidation products and sulfides together with Si, refines the base metal and HAZ structure, and improves toughness. However, if added in a large amount, weldability and HAZ toughness will deteriorate, so the content should be 2.2% or less.
Ａｌは、一般に脱酸剤として添加するが、Ａｌは酸素と
の親和力が強く、過剰に添加すると他の酸化物、および
その生成に影響を及ぼす。すなわち、溶鋼中のＭｎＯや
ＳｉＯ２を還元してしまい、Ａｌ２ Ｃｈ を形成す
る。 Ａ１２ （ｈ が多量になるとクラスターを形
成し、サイズが大きくなりＴｉ１Ｚｒ添加による微細効
果が期待できない。そのため０．００８％以下にＡ７添
加量を限定する。Al is generally added as a deoxidizing agent, but Al has a strong affinity with oxygen, and when added in excess, it affects other oxides and their formation. That is, MnO and SiO2 in the molten steel are reduced to form Al2Ch. If A12 (h) is in a large amount, clusters will be formed and the size will become large, making it impossible to expect a fine effect due to the addition of Ti1Zr.Therefore, the amount of A7 added is limited to 0.008% or less.
その他本発明鋼にはＣｕ、Ｎｉ、Ｃｒ、Ｎｂ。Other steels of the present invention include Cu, Ni, Cr, and Nb.
Ｍｏ５Ｖ、ＢおよびＣａの少くとも１種を添加するが、
通常厚板、鋼管等溶接構造用鋼に含有させる範囲である
。すなわち、Ｃｕは耐食性、耐水素誘起割れ性を付与し
圧延時の割れ発生を防止するために０．０５〜１，００
％とする。At least one of Mo5V, B and Ca is added,
This is the range normally contained in steel for welded structures such as thick plates and steel pipes. That is, Cu has a content of 0.05 to 1,000 to provide corrosion resistance and hydrogen-induced cracking resistance and to prevent cracking during rolling.
%.
Ｎ］は、耐食性と共に母材の強度靭性を向上させるが多
量添加は溶接性に好ましくないため０．０５〜４．０％
とする。N] improves the strength and toughness of the base metal as well as corrosion resistance, but adding a large amount is not favorable for weldability, so it is 0.05 to 4.0%.
shall be.
ＣｒもＮｉと同様の効果を期待でき、更に溶接部強度を
高めるが、接合部靭性を低下させないため１０％以下と
し、００５％以下では効果がみられない。Cr can also be expected to have the same effect as Ni and further increase the strength of the welded part, but in order not to reduce the toughness of the joint, it should be kept at 10% or less, and no effect will be seen at 0.005% or less.
ＭＯは母材の強度、靭性を向上させる元素であり多量添
加は溶接部を劣化するので０．０５〜０．４％とする。MO is an element that improves the strength and toughness of the base metal, and adding a large amount deteriorates the welded joint, so it is set at 0.05 to 0.4%.
Ｎｂ、Ｖは母材強度、ＨＡＺ靭性の改善に有効であるが
、多量添加はこれらの特性に反って有害となる。そのた
めにそれぞれ０．００３〜０．０６０％、０、００５〜
０．０８０％とする。Although Nb and V are effective in improving base material strength and HAZ toughness, adding large amounts will adversely affect these properties and be harmful. Therefore, 0.003~0.060% and 0,005~
It shall be 0.080%.
Ｂは、鋼の焼入れ性を向上させ、母材強度を上昇させる
。接合部に固溶したＢは、粒界フェライトの生成を抑制
し、ＨＡＺ靭性を向上する。過剰添加はかえってＨＡＺ
を硬化するため３〜２０ｐｐｍとする。B improves the hardenability of steel and increases the strength of the base material. B dissolved in the joint suppresses the formation of grain boundary ferrite and improves HAZ toughness. Excessive addition may actually cause HAZ
3 to 20 ppm for curing.
Ｃａは粗大な硫化物の形態を制御し、低温靭性を向上さ
せると共に耐水素誘起割れ性を改善する。Ca controls the morphology of coarse sulfides, improves low-temperature toughness, and improves hydrogen-induced cracking resistance.
多量添加するとＣａｂＳＣａＳが多くなり大型介在物と
なり、又、ＭｎＳの生成が阻害されるので反って溶接性
に悪影響を及ぼす。そのため０．００１〜０．００５％
の範囲とする。When added in a large amount, CabSCaS increases to form large inclusions, and since the generation of MnS is inhibited, it warps and adversely affects weldability. Therefore 0.001~0.005%
The range shall be .
（実施例１）
高周波誘導溶解法により、第１表に示す組成の鋼を溶製
した。すなわち、酸素を含む電解鉄にＣ５Ｍｎ、Ｓｉを
添加し、その後Ｔｉ５Ｚｒを添加した。それぞれの場合
のＣ（Ｔｉ）＋Ｃ（Ｚｒ）とＣ，（０）−Ｃ２（Ｏ）の
比を、第１表に併記した。このようにして得た鋼につい
て、酸化物個数とその上に析出したＭｎＳの個数を調査
し、その結果を第１表に示した。(Example 1) Steel having the composition shown in Table 1 was produced by high frequency induction melting. That is, C5Mn and Si were added to electrolytic iron containing oxygen, and then Ti5Zr was added. The ratios of C(Ti)+C(Zr) and C,(0)-C2(O) in each case are also listed in Table 1. Regarding the steel thus obtained, the number of oxides and the number of MnS precipitated thereon were investigated, and the results are shown in Table 1.
これにより、Ｃ（Ｔ ｉ） ＋Ｃ（Ｚ ｒ）が本発明範
囲である０、４Ｘ （Ｃ，（０）−Ｃ，（０）） 〜３
ｘ （Ｃ＋ （０） Ｃ２（Ｏ）） に入っていれ
ば、酸化物個数の増加と共に、十分なＭｎＳ析出が得（
実施例２）
実際の製造工程において、第２表に示す組成の鋼を溶製
し、連鋳法にて凝固させた。成分は本発明範囲である０
、４ｘ （Ｃ，（０）−Ｃ２（Ｏ））〜３Ｘ （Ｃ，（
０）−ｃ２ （０））の条件を満たすもの２水準と、比
較としてＴｉ単独添加のものとした。上記２水準はＺｒ
添加量の下限値を知る目的で、Ｚｒ添加量を４０ｐｐｍ
と６０ｐｐｍとした。各試料中における生成した酸化物
の個数を測定した結果を第２図に示すが、本発明範囲を
満たすＴｌＺｒ添加により、鋳片厚み方向中心部での酸
化物個数が大幅に増加した。また、Ｚ ｒ ４０ｐｐｍ
添加では、その効果は大きくないことから、Ｚｒ添加量
の下限値を５０ｐｐｍとする必要があることが判った。As a result, C(T i) +C(Z r) is within the range of the present invention, 0,4X (C,(0)-C,(0)) ~3
x (C+ (0) C2(O)), sufficient MnS precipitation is obtained as the number of oxides increases (
Example 2) In an actual manufacturing process, steel having the composition shown in Table 2 was melted and solidified by a continuous casting method. The ingredients are within the scope of the present invention.
, 4x (C, (0)-C2(O)) ~ 3X (C, (
0)-c2 (0)) Two levels were used, and for comparison, one in which Ti was added alone. The above two levels are Zr
For the purpose of knowing the lower limit of the amount added, the amount of Zr added was set to 40 ppm.
and 60 ppm. The results of measuring the number of oxides generated in each sample are shown in FIG. 2, and the addition of TlZr that satisfies the range of the present invention significantly increased the number of oxides at the center in the thickness direction of the slab. Also, Z r 40ppm
Since the effect of addition is not large, it was found that the lower limit of the amount of Zr added needs to be set at 50 ppm.
また、第３図に示すように、本発明鋼（第２表Ａ鋼）に
は、Ｔｉ脱酸鋼に比し、多数のＭｎＳが酸（発明の効果
）
以上説明したように、本発明のＴｉおよびＺｒ脱酸を行
った鋼は、鋳片厚み方向中心部の酸化物が著しく増加し
、溶接熱影響部靭性の優れた鋼材を得ることができる。Furthermore, as shown in FIG. 3, the steel of the present invention (Steel A in Table 2) has a larger amount of MnS in acid than the Ti-deoxidized steel (effects of the invention). Steel that has undergone Ti and Zr deoxidation has a marked increase in oxides at the center in the thickness direction of the slab, making it possible to obtain a steel material with excellent weld heat-affected zone toughness.
第１図は、種々のＣ（Ｔ ｉ） 十Ｃ（Ｚ ｒ）の値で
の酸化物個数とＭｎＳ析出個数との関係を示した図、第
２図は、Ｚｒを添加した場合の酸化物の鋳片厚み方向の
分布を示した図、第３図は、酸化物上に析出したＭｎＳ
の個数を示した図である。Figure 1 shows the relationship between the number of oxides and the number of MnS precipitates at various values of C(T i) C(Z r), and Figure 2 shows the relationship between the number of oxides and the number of MnS precipitates when Zr is added. Figure 3 shows the distribution of MnS in the slab thickness direction.
It is a figure showing the number of objects.
Claims (1)
．０２〜０．５％を含有し、かつＡｌを０．００８％以
下にした組成を有する炭素鋼材に、ＴｉとＺｒを添加し
、ＴｉとＺｒの濃度を下記式の範囲内としたことを特徴
とする溶接熱影響部靭性の優れた鋼材。 ０．４×｛Ｃ＿１（Ｏ）−Ｃ＿２（Ｏ）｝≦Ｃ（Ｚｒ）
＋Ｃ（Ｔｉ）≦３×｛Ｃ＿１（Ｏ）−Ｃ＿２（Ｏ）｝か
つＣ（Ｚｒ）≧５０（ｐｐｍ） ここでＣ（Ｚｒ）；Ｚｒ濃度（ｐｐｍ） Ｃ（Ｔｉ）；Ｔｉ濃度（ｐｐｍ） Ｃ＿１（Ｏ）；Ｍｎ及びＳｉを添加する前の溶鋼中酸素
濃度（ｐｐｍ） Ｃ＿２（Ｏ）；Ｍｎ及びＳｉ、必要に応じてＡｌを添加
した後の溶鋼溶鋼中酸素濃度（ｐｐｍ） （２）重量％として、Ｃ：≦０．２％、Ｍｎ：０．３〜
２．２％、Ｓｉ：０．０２〜０．５％かつＡｌ：０．０
０８％以下を含有する炭素鋼材に Ｃｕ：０．０５〜１．００％、 Ｎｉ：０．０５〜４．０％、 Ｃｒ：０．０５〜１．０％、 Ｍｏ：０．０５〜０．４％、 Ｎｂ：０．００３〜０．０６０％、 Ｖ：０．００５〜０．０８０％、 Ｂ：０．０００３〜０．００２０％、 Ｃａ：０．００１〜０．００５％、 の１種又は２種以上を含有し、更に、ＴｉとＺｒとを下
記式で示す濃度範囲で添加したことを特徴とする溶接熱
影響部靭性の優れた鋼材。 ０．４×｛Ｃ＿１（Ｏ）−Ｃ＿２（Ｏ）｝≦Ｃ（Ｚｒ）
＋Ｃ（Ｔｉ）≦３×｛Ｃ＿１（Ｏ）−Ｃ＿２（Ｏ）｝か
つＣ（Ｚｒ）≧５０（ｐｐｍ） ここでＣ（Ｚｒ）；Ｚｒ濃度（ｐｐｍ） Ｃ（Ｔｉ）；Ｔｉ濃度（ｐｐｍ） Ｃ＿１（Ｏ）：Ｍｎ及びＳｉを添加する前の溶鋼中酸素
濃度（ｐｐｍ） Ｃ＿２（Ｏ）；Ｍｎ及びＳｉ必要に応じてＡｌを添加し
た後の溶鋼中酸素濃度（ｐｐｍ）[Claims] (1) Mn: 0.3 to 2.2% by weight, Si: 0
．． A carbon steel material having a composition containing 02 to 0.5% Al and 0.008% or less Al, Ti and Zr are added, and the concentration of Ti and Zr is within the range of the following formula. A steel material with excellent weld heat affected zone toughness. 0.4×{C_1(O)-C_2(O)}≦C(Zr)
+C(Ti)≦3×{C_1(O)-C_2(O)} and C(Zr)≧50(ppm) where C(Zr); Zr concentration (ppm) C(Ti); Ti concentration (ppm) C_1(O); Oxygen concentration in molten steel before adding Mn and Si (ppm) C_2(O); Oxygen concentration in molten steel after adding Mn and Si, and if necessary Al (ppm) (2) As weight%, C: ≦0.2%, Mn: 0.3~
2.2%, Si: 0.02-0.5% and Al: 0.0
Cu: 0.05-1.00%, Ni: 0.05-4.0%, Cr: 0.05-1.0%, Mo: 0.05-0.08% or less. 4%, Nb: 0.003-0.060%, V: 0.005-0.080%, B: 0.0003-0.0020%, Ca: 0.001-0.005%, one type of A steel material having excellent weld heat-affected zone toughness, characterized by containing Ti and Zr in a concentration range shown by the following formula. 0.4×{C_1(O)-C_2(O)}≦C(Zr)
+C(Ti)≦3×{C_1(O)-C_2(O)} and C(Zr)≧50(ppm) where C(Zr); Zr concentration (ppm) C(Ti); Ti concentration (ppm) C_1(O): Oxygen concentration in molten steel (ppm) before adding Mn and Si C_2(O): Oxygen concentration in molten steel after adding Mn and Si (aluminum if necessary) (ppm)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2091876A JPH0742545B2 (en) | 1990-04-06 | 1990-04-06 | Weld heat-affected zone steel with excellent toughness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2091876A JPH0742545B2 (en) | 1990-04-06 | 1990-04-06 | Weld heat-affected zone steel with excellent toughness |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03291356A true JPH03291356A (en) | 1991-12-20 |
| JPH0742545B2 JPH0742545B2 (en) | 1995-05-10 |
Family
ID=14038763
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2091876A Expired - Fee Related JPH0742545B2 (en) | 1990-04-06 | 1990-04-06 | Weld heat-affected zone steel with excellent toughness |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0742545B2 (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52715A (en) * | 1975-06-24 | 1977-01-06 | Nippon Steel Corp | Steel plates with excellent weldability |
| JPS52123918A (en) * | 1976-04-12 | 1977-10-18 | Kobe Steel Ltd | Weather resistant steel with excellent weldability for large heat input welding |
| JPS63149354A (en) * | 1986-12-12 | 1988-06-22 | Sumitomo Metal Ind Ltd | High tension steel sheet for high heat input welding and manufacture thereof |
| JPH01159356A (en) * | 1987-12-16 | 1989-06-22 | Nippon Steel Corp | High tension steel having superior tougeness at weld heat-affected zone |
| JPH01228643A (en) * | 1988-03-09 | 1989-09-12 | Nippon Steel Corp | Method for uniformly and finely dispersing-precipitating mns in steel |
-
1990
- 1990-04-06 JP JP2091876A patent/JPH0742545B2/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52715A (en) * | 1975-06-24 | 1977-01-06 | Nippon Steel Corp | Steel plates with excellent weldability |
| JPS52123918A (en) * | 1976-04-12 | 1977-10-18 | Kobe Steel Ltd | Weather resistant steel with excellent weldability for large heat input welding |
| JPS63149354A (en) * | 1986-12-12 | 1988-06-22 | Sumitomo Metal Ind Ltd | High tension steel sheet for high heat input welding and manufacture thereof |
| JPH01159356A (en) * | 1987-12-16 | 1989-06-22 | Nippon Steel Corp | High tension steel having superior tougeness at weld heat-affected zone |
| JPH01228643A (en) * | 1988-03-09 | 1989-09-12 | Nippon Steel Corp | Method for uniformly and finely dispersing-precipitating mns in steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0742545B2 (en) | 1995-05-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0177851B1 (en) | Steel materials for welded structures | |
| JPH08158006A (en) | High strength steel excellent in toughness in weld heat-affected zone | |
| JPH0577740B2 (en) | ||
| JPH093597A (en) | Steel for low temperature use excellent in toughness of weld heat affected zone and its production | |
| JPH05171341A (en) | Production of thick steel plate excellent in toughness in welding heat-affected zone | |
| JP3323414B2 (en) | Steel with excellent heat-affected zone toughness in large heat input welding and method for producing the same | |
| JP7223210B2 (en) | Precipitation hardening martensitic stainless steel sheet with excellent fatigue resistance | |
| JPH03162522A (en) | Manufacture of high tension steel plate having superior toughness of high heat input weld heat-affected zone | |
| JP3852118B2 (en) | Steel material with excellent toughness of weld heat affected zone | |
| JP3215296B2 (en) | Method of manufacturing steel material for welded structures with excellent toughness of weld heat affected zone | |
| JP2000226633A (en) | Steel for electron beam welding excellent in toughness | |
| JPH093600A (en) | Steel for welding structure excellent in toughness weld heat affected zone | |
| JPH03291356A (en) | Steel having excellent toughness in weld heat affected zone | |
| JPH08144008A (en) | High tensile strength steel and its production | |
| JP3502805B2 (en) | Method for producing steel with excellent toughness in weld joint | |
| JPH08232042A (en) | Corrosion resisting steel for resistance welded tube | |
| JP4355866B2 (en) | Steel material excellent in welding heat-affected zone characteristics and method for producing the same | |
| JP3238271B2 (en) | Method for producing low temperature steel with excellent heat-affected zone toughness in large heat input welding | |
| JP3539120B2 (en) | Austenitic stainless steel with excellent hot workability | |
| JPH05271864A (en) | Steel having dispersed fine grain including mn oxide and al oxide | |
| JP3224677B2 (en) | Low temperature steel for welding | |
| JPH07266005A (en) | Production of steel having excellent toughness to welded heat affected part by synchronized belt type continuous casting method | |
| JPH093598A (en) | Steel for low temperature use excellent in toughness of weld heat affected zone | |
| CN116171334A (en) | Precipitation hardening martensitic stainless steel having excellent fatigue resistance | |
| TW202417162A (en) | Ferritic stainless steel welding wire and welded part |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080510 Year of fee payment: 13 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090510 Year of fee payment: 14 |
|
| LAPS | Cancellation because of no payment of annual fees |