JPH01290751A - High-strength non-heattreated steel bar - Google Patents
High-strength non-heattreated steel barInfo
- Publication number
- JPH01290751A JPH01290751A JP12066088A JP12066088A JPH01290751A JP H01290751 A JPH01290751 A JP H01290751A JP 12066088 A JP12066088 A JP 12066088A JP 12066088 A JP12066088 A JP 12066088A JP H01290751 A JPH01290751 A JP H01290751A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- strength
- hardenability
- steel bar
- rolled state
- 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 38
- 239000010959 steel Substances 0.000 title claims abstract description 38
- 239000000463 material Substances 0.000 claims abstract description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000001816 cooling Methods 0.000 claims abstract description 5
- 238000005098 hot rolling Methods 0.000 claims abstract description 4
- 239000012535 impurity Substances 0.000 claims abstract description 3
- 229910052742 iron Inorganic materials 0.000 claims abstract description 3
- 229910052804 chromium Inorganic materials 0.000 abstract description 6
- 229910052748 manganese Inorganic materials 0.000 abstract description 6
- 229910052799 carbon Inorganic materials 0.000 abstract description 5
- 229910052758 niobium Inorganic materials 0.000 abstract description 5
- 239000000203 mixture Substances 0.000 abstract description 4
- 229910052720 vanadium Inorganic materials 0.000 abstract description 4
- 239000010953 base metal Substances 0.000 abstract description 3
- 229910052710 silicon Inorganic materials 0.000 abstract description 3
- 238000000034 method Methods 0.000 abstract description 2
- 230000007547 defect Effects 0.000 abstract 1
- 230000001105 regulatory effect Effects 0.000 abstract 1
- 229910001563 bainite Inorganic materials 0.000 description 7
- 238000005728 strengthening Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000005096 rolling process Methods 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910000859 α-Fe Inorganic materials 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- 229910001562 pearlite Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 235000019362 perlite Nutrition 0.000 description 1
- 239000010451 perlite Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000004881 precipitation hardening Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000005496 tempering Methods 0.000 description 1
- 229940035289 tobi Drugs 0.000 description 1
- NLVFBUXFDBBNBW-PBSUHMDJSA-N tobramycin Chemical compound N[C@@H]1C[C@H](O)[C@@H](CN)O[C@@H]1O[C@H]1[C@H](O)[C@@H](O[C@@H]2[C@@H]([C@@H](N)[C@H](O)[C@@H](CO)O2)O)[C@H](N)C[C@@H]1N NLVFBUXFDBBNBW-PBSUHMDJSA-N 0.000 description 1
Landscapes
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は、高強度棒鋼等の製）告において、熱間圧延後
の焼入・焼戻し処理を行なうことなく圧延後放冷ままで
母材、溶接部ともに引張強ざＦ！、ＯＫ３／−以上、０
．２％耐力６５Ｎび／ｍｙ／ｒ以上、伸び１０％以上で
おる高強度調質棒鋼に関するものである。Detailed Description of the Invention [Industrial Field of Application] The present invention is applicable to the manufacture of high-strength steel bars, etc., in which the base material is left to cool after rolling without quenching or tempering after hot rolling. , the tensile strength of both welded parts is F! , OK3/- or more, 0
．． This relates to a high-strength tempered steel bar with a 2% yield strength of 65 N/my/r or more and an elongation of 10% or more.
［従来の技術］
従来、引張強さが８０ＫＦｉ／−以上の高強度棒鋼は、
圧延後再加熱して焼入れ焼戻し処理を行ない使用に供さ
れているが、溶接施行１３Ｊ、び曲げ加工施行ができな
い欠点があり、製造コストも高い。そこで、近年、高強
度棒鋼の製造において、上記欠点を改善するため、中炭
素鋼に微量のｖ、Ｎｔ）、Ｔｉ等の析出硬化元素を添加
した非調質鋼を用い、熱間圧延ままで所要の特性が１！
Ｉられる高強度ＪＬ調ｒ棒鋼が注［１されている。[Conventional technology] Conventionally, high-strength steel bars with a tensile strength of 80KFi/- or more,
After rolling, it is reheated, quenched and tempered and put into use, but it has the drawback that it cannot be welded or bent, and the manufacturing cost is high. Therefore, in recent years, in the production of high-strength steel bars, in order to improve the above-mentioned drawbacks, non-heat-treated steels with trace amounts of precipitation hardening elements such as v, Nt) and Ti added to medium carbon steels have been used to produce high-strength steel bars as hot-rolled. The required characteristics are 1!
High-strength JL-toned steel bars are listed.
非調質鋼の圧延ままの強磨は、炭素当量と良い相関があ
り、８０に３／ｍｄｒ以上の高強度を圧延ままで１ｑる
には炭素当量を高くする必要がある。しかし一般に炭素
当量が増加するとと−しに、ＭｎやＣｒの添加量が多く
なるので焼入性が高くなり、対象とする棒鋼の径によっ
ては、１工延後の空冷によってベイナイト組織が生成し
延性が劣化覆るため所要の特性を満足できない。The hard polishing of non-tempered steel as rolled has a good correlation with the carbon equivalent, and in order to achieve a high strength of 80 to 3/mdr or higher by 1q in the as-rolled state, it is necessary to increase the carbon equivalent. However, in general, as the carbon equivalent increases, the amount of Mn and Cr added increases, resulting in higher hardenability, and depending on the diameter of the target steel bar, a bainite structure may be formed by air cooling after one rolling. The required properties cannot be satisfied because the ductility deteriorates.
また、棒鋼は溶接施行されるため、溶接部の延性および
曲げ性も車装な特性であるが、焼入性が高くなると溶接
熱影響部にマルテンサイトやベイナイトが生成しやづく
なり延性や曲げ性が茗しく劣化する。In addition, since steel bars are welded, the ductility and bendability of the welded part are also characteristics that are suitable for automotive equipment, but as the hardenability increases, martensite and bainite are more likely to form in the weld heat-affected zone, resulting in a decrease in ductility and bendability. Sexuality deteriorates dramatically.
［発明が解決しようとする課題］
本発明は上記課題を解決し圧延ままで高強度で溶接性に
優れた非調質棒鋼を開発することでおる。[Problems to be Solved by the Invention] The present invention solves the above-mentioned problems and develops a non-tempered steel bar that has high strength and excellent weldability even when rolled.
［課題を解決覆るための手段］
上記課題を解決するため化学成分の異なる種々の鋼材を
試作研究した結果、圧延後の冷却過程でベイナイトが生
成しないように鋼の焼入性をコントロールするとともに
、ＶとＮｂの複合添加により所要の強度および延性を満
足する非調質棒鋼が１ｑられることを見い出した。[Means for solving and overcoming the problems] In order to solve the above problems, as a result of prototyping and researching various steel materials with different chemical compositions, we decided to control the hardenability of the steel so that bainite would not be generated during the cooling process after rolling. It has been found that by adding V and Nb in combination, 1q of non-tempered steel bars can be produced that satisfy the required strength and ductility.
したがって本発明は、Ｅｌ ）ｒＡ、溶接部ともに引張
強ざ８０ＫＦＪ／ｍｒＡ以上、０．２％耐力６５Ｋｇ／
ｍｒＡ以上、伸び１０％以上の機械的性質を有し圧延後
の主要組織がフェライトパーライトでおる高強度非調質
棒鋼であり、重量％で、
Ｃ０．３５〜０．４５％
Ｓｉ ０．１５〜０．５０％
Ｍ ｎ ０．８０〜１．２０％
Ｃｒ ０．２０％以下
Ｖ ０．１０−、〜０．２５％
Ｎｂ ０．０２０〜ｏ、 ０５０％
残部が実質的に鉄及び不可避的不純物よりなり、焼入Ｍ
、 Ｄ Ｉが
り、Ｉ＜１．３インチ
を満足することを特徴とし、Ｍ ｎ、Ｃｒ減少に伴なう
強度低下をＶ、Ｎｂの複合添加により確保づるものであ
る。Therefore, the present invention has a tensile strength of 80 KFJ/mrA or more for both El
It is a high-strength non-tempered steel bar with mechanical properties of mrA or more and elongation of 10% or more, and the main structure after rolling is ferrite pearlite, and in weight %, C0.35~0.45% Si 0.15~ 0.50% Mn 0.80-1.20% Cr 0.20% or less V 0.10-, ~0.25% Nb 0.020-0, 050% The remainder is substantially iron and inevitable impurities quenched M
, DI, and I<1.3 inches, and the reduction in strength due to the decrease in Mn and Cr is ensured by the combined addition of V and Nb.
［作 用］
焼入性ＤＩを１，３インチ以下に設定した理由は、ＤＩ
が１．３インチを越えると、棒径か細い場合にベイナイ
トが生成し延性が劣化するためである。[Function] The reason for setting the hardenability DI to 1.3 inches or less is that the DI
This is because if the rod diameter exceeds 1.3 inches, bainite will be generated and the ductility will deteriorate if the rod diameter is small.
次に本発明における鋼成分の限定理由について述べる。Next, the reasons for limiting the steel components in the present invention will be described.
Ｃ：高強度棒鋼を得るために０．３５％以上必要である
が、０．４５％を越えると母材の延性ならびに溶接部の
延性、曲げ性が劣化するので上限を０．４５％とした。C: 0.35% or more is necessary to obtain a high-strength steel bar, but if it exceeds 0.45%, the ductility of the base metal and the ductility and bendability of the welded part will deteriorate, so the upper limit was set at 0.45%. .
Ｓｉ：脱酸作用の他、フエライ１〜組織の強化に有効な
元素であるが、０，１５％以下では効果が少なく、また
０、５％を越えると焼入性が上昇するので上限を０．５
％とした。Si: In addition to its deoxidizing effect, it is an effective element for strengthening the Ferrite 1~ structure, but if it is less than 0.15%, it has little effect, and if it exceeds 0.5%, the hardenability increases, so the upper limit should be set to 0. .5
%.
Ｍｎ：鋼の強度上界ざぜるには必須の元素であり、少く
とも０．８０％を必要とする。しかし１，２％を越える
とベイナイトが生成しやすくなるため上限を１．２％と
した。１
Ｃｒ：Ｍｎと同様に鋼の強化に有効な元素であるが、Ｉ
） Ｉを１．３インチ以下にコントロールするために上
限を０．２０％とした。Mn: An essential element to increase the strength of steel, and requires at least 0.80%. However, if it exceeds 1.2%, bainite tends to form, so the upper limit was set at 1.2%. 1 Cr: Like Mn, it is an effective element for strengthening steel, but I
) In order to control I to 1.3 inches or less, the upper limit was set to 0.20%.
Ｖ：鋼の強化に必須の元素であり、ＤＩが１，３インヂ
以下で０．２％耐力を６５にび／ｍｒＡ以上にするため
には少くとも０．１０％は必要である。一方過閣に添加
しても強化に効果がないので上限を０．２５％としｌこ
。V: An essential element for strengthening steel, and at least 0.10% is required in order to increase the 0.2% yield strength to 65 mm/mrA or higher at a DI of 1.3 inches or lower. On the other hand, even if it is added to Kokaku, it has no effect on strengthening, so the upper limit is set at 0.25%.
Ｎｂ：Ｖと同様、鋼の強化に有効な元素であり、添加量
は強化に最も効果のある０、０２０−０．０５０％とし
た。Nb: Like V, it is an element effective in strengthening steel, and the amount added was set to 0.020-0.050%, which is most effective in strengthening.
［実施例］ 次に本発明の実施例を示す。[Example] Next, examples of the present invention will be shown.
３０を電気炉または６０を電気炉で第１表に示づ一化学
成’ｔ）の鋼を溶製し、責形棒鋼Ｄ１（）、１）１３お
よび１）１６に圧延した。A steel having a chemical composition shown in Table 1 was melted in an electric furnace (No. 30) or an electric furnace (No. 60) and rolled into shaped steel bars D1 (), 1) 13 and 1) 16.
［）１０． ＤＩ３および０１６の機械的ｔ！ｌ貿を第
２表に、［）１３のミクロ組織を示す図面代用写真を第
１図に示づ。[)10. Mechanical t! of DI3 and 016! 1 trade is shown in Table 2, and a photograph substituted for a drawing showing the microstructure of [)13 is shown in Fig. 1.
本発明鋼の成分範囲鋼でおるＮｏ、 Ａは引張強さ９９
に’Ｊ／ｍｒＡ以上、０．２％耐カフ６ＫＦＪ／ｍｒＡ
以上、延び１３％以上のｈｔｔを示し、所要の特性を十
分満足している。またミクロ組織も均一なフェライト・
パーライトで必る。Inventive steel composition range Steel No. A indicates tensile strength of 99.
Ni'J/mrA or more, 0.2% resistance cuff 6KFJ/mrA
As described above, the elongation htt was 13% or more, and the required characteristics were fully satisfied. In addition, the microstructure is uniform ferrite.
Must use perlite.
一乃比較鋼Ｎ０．１３は０．２％耐力が低くまたＭｎ１
ｄか１．２５％と多いため、焼入性［）Ｉが１、フイン
ブとやや高く、そのためＤｌｏでベイナイト組織となり
、伸びがやや低下している。Ichino comparative steel N0.13 has a 0.2% lower yield strength and Mn1
Since d is as high as 1.25%, the hardenability [)I is slightly high at 1 and 5%, so that Dlo becomes a bainitic structure and the elongation is slightly reduced.
また、比較、＞１４Ｎｏ、 Ｃは、Ｍｎ、Ｃｒが多く、
ＤＩが２．１インチと高いため、［）１０および［）１
３ともにベイナイト組織となっており、伸びが目標値を
わずかに上回る程度の（ｉＱでおる。Also, for comparison, >14No, C has a lot of Mn and Cr,
Since the DI is as high as 2.1 inches, [)10 and [)1
Both 3 have a bainite structure, and the elongation is slightly above the target value (iQ).
以上のように本発明鋼の１−５徴は比較鋼に比べＶ添加
量が多く、さらにＮ［）を添加しているため０゜２％耐
力が高くなっていることと、ベイナイトが生成しないよ
う焼入れ性１）Ｉをコントロールしているため均一１３
フエライ１〜・パーライト組織であり比較鋼に比べ伸び
飴が優れている。As mentioned above, the characteristics 1-5 of the steel of the present invention are that it has a higher 0°2% yield strength due to the addition of more V than the comparison steel, and also the addition of N[), and that bainite does not form. Hardenability 1) Uniform because I is controlled 13
It has a pearlite structure and has better elongation properties than comparative steels.
次に溶接部（１試験結果の一例として［）１３の７ラツ
シユバツト溶接材の引張および試験結果を第３表に示す
。Next, Table 3 shows the tensile and test results of the 7-latch butt welded material of No. 13 as an example of the results of one test.
Ｎｏ、△およびＮｏ、 Ｂは所要の特性値を満足してい
るが、Ｎｏ、Ｃは伸びが低く曲げ試験で折損している。No., △ and No., B satisfied the required characteristic values, but No. and C had low elongation and broke in the bending test.
以上のようなＮｏ、ＡはＲ１材および溶接部ともに所要
の特性値を満足している。In No. and A as described above, both the R1 material and the welded portion satisfy the required characteristic values.
［発明の効果１
以上説明したように本発明鋼は圧延ままで母材、溶接部
ともに引張強さ８０Ｋｙ／−以一ヒ、０．２％耐力６５
Ｎび／ ｍｒＡ以上、伸び１０％以上の優れた材質特性
を示し、従来の焼入れ焼戻し材の欠点を改善するとと乙
に、熱処理を省略でさるためコスト低減にも、大きな効
果を°ｂたらすものである。[Effect of the invention 1 As explained above, the steel of the present invention has a tensile strength of 80 Ky/- and a 0.2% yield strength of 65 in both the base metal and the welded part as rolled.
It exhibits excellent material properties such as N/mrA or more and elongation of 10% or more, and has a great effect on improving the shortcomings of conventional quenched and tempered materials, as well as reducing costs by omitting heat treatment. It is.
り）１図は本発明１１ＱＮ０．△、比較１１４Ｎｏ、［
３，Ｎ０９Ｃの各金属組織の顕微鏡図面代用ｂ゛真であ
る。
Ｎｏ、 Ａ・・・・・・・・・・・・本発明鋼″ｔｊＪ
ｉ’ｌ 出 願 人 トビ−工業株式会社回
Ｌ 北越メタル株式会社
第１図ri) Figure 1 shows the present invention 11QN0. △, Comparison 114 No, [
3. This is a substitute for a microscopic drawing of each metallographic structure of N09C. No. A・・・・・・・・・・Invention steel “tjJ
i'l Applicant: Tobi Industries Co., Ltd.
L Hokuetsu Metal Co., Ltd. Figure 1
Claims (1)
ＤＩが１．３インチ以下の鋼材を通常の熱間圧延後、自
然空冷により得られる高強度でかつ溶接性に優れた非調
質棒鋼。[Claims] 1. C0.35-0.45% Si0.15-0.50% Mn0.80-1.20% Cr0.20% or less V0.10-0.25% Nb0. 020-0.050% High strength and weldability obtained by natural air cooling after normal hot rolling of a steel material with hardenability DI of 1.3 inches or less, with the remainder essentially consisting of iron and unavoidable impurities. Non-tempered steel bar with excellent properties.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12066088A JPH01290751A (en) | 1988-05-19 | 1988-05-19 | High-strength non-heattreated steel bar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12066088A JPH01290751A (en) | 1988-05-19 | 1988-05-19 | High-strength non-heattreated steel bar |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01290751A true JPH01290751A (en) | 1989-11-22 |
Family
ID=14791741
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12066088A Pending JPH01290751A (en) | 1988-05-19 | 1988-05-19 | High-strength non-heattreated steel bar |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01290751A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5852458A (en) * | 1981-09-22 | 1983-03-28 | Kawasaki Steel Corp | Nonquenched and tempered steel with high strength and toughness |
| JPS6250411A (en) * | 1985-08-30 | 1987-03-05 | Kobe Steel Ltd | Production of rolled steel material having excellent homogeneity |
| JPS6296653A (en) * | 1981-10-20 | 1987-05-06 | Daido Steel Co Ltd | Nonrefined structural steel |
| JPS62107045A (en) * | 1985-11-01 | 1987-05-18 | Nippon Steel Corp | Wire rod for long-sized high tension steel wire |
| JPS62199750A (en) * | 1986-02-27 | 1987-09-03 | Nippon Steel Corp | Unrefined steel bar having superior toughness and its manufacture |
-
1988
- 1988-05-19 JP JP12066088A patent/JPH01290751A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5852458A (en) * | 1981-09-22 | 1983-03-28 | Kawasaki Steel Corp | Nonquenched and tempered steel with high strength and toughness |
| JPS6296653A (en) * | 1981-10-20 | 1987-05-06 | Daido Steel Co Ltd | Nonrefined structural steel |
| JPS6250411A (en) * | 1985-08-30 | 1987-03-05 | Kobe Steel Ltd | Production of rolled steel material having excellent homogeneity |
| JPS62107045A (en) * | 1985-11-01 | 1987-05-18 | Nippon Steel Corp | Wire rod for long-sized high tension steel wire |
| JPS62199750A (en) * | 1986-02-27 | 1987-09-03 | Nippon Steel Corp | Unrefined steel bar having superior toughness and its manufacture |
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