JP4025515B2 - Steel plate for recliner gear with excellent workability, hardenability and weldability, and method for producing the same - Google Patents
Steel plate for recliner gear with excellent workability, hardenability and weldability, and method for producing the same Download PDFInfo
- Publication number
- JP4025515B2 JP4025515B2 JP2001120204A JP2001120204A JP4025515B2 JP 4025515 B2 JP4025515 B2 JP 4025515B2 JP 2001120204 A JP2001120204 A JP 2001120204A JP 2001120204 A JP2001120204 A JP 2001120204A JP 4025515 B2 JP4025515 B2 JP 4025515B2
- Authority
- JP
- Japan
- Prior art keywords
- less
- workability
- hardenability
- weldability
- steel plate
- 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.)
- Expired - Fee Related
Links
Images
Landscapes
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Description
【０００１】
【発明の属する技術分野】
自動車のリクライナーシートの角度調整に用いられるアームポールに組み込まれて使用されるギヤー部品の製造に適した加工性、焼き入れ性、溶接性が優れたリクライナーギヤー用鋼板及びその製造方法。
【０００２】
【従来の技術】
自動車のリクライナーのアームポールに組み込まれるギヤー部品は、従来、Ｓ４５Ｃを用いファインブランキングでの半抜きによりギヤーを成型し、ボルト締めで固定することにより製造されていた。近年、小型化、動きの滑らかさ等から、ギヤーの小モジュール化が要請され、より加工性への要求が厳しくなっている。また、従来のボルト固定による組み立て方法から、溶接による組み立てにより、コスト低下、小型化も進められている。
【０００３】
この溶接組み立て方法に用いられる鋼板に要求される特性は、耐摩耗性の点から表面硬さがＨｖ：５００以上、溶接割れが生じないこと及び小モジュールのギヤー成型に必要な加工性が要求されている。また、衝撃荷重に耐える衝撃特性が要求されている。表面硬さは鋼板の焼き入れ性が良好なほど、言い換えると、炭素量、Ｍｎ、Ｃｒ、Ｍｏ等の合金元素の添加量が高いほど良好になる。一方、溶接割れ性は炭素量、Ｍｎ、Ｃｒ、Ｍｏ等の合金元素が少ないほど良好となる。衝撃特性は一般に硬さが高くなると劣化し、合金元素量が多いと焼き入れ硬さが高くなり、衝撃特性も低下する。この衝撃特性の劣化を回避するため、低炭素鋼板に浸炭して焼き入れする方法が検討され、十分な表面硬さを得るためには浸炭量を十分に確保する必要があることが知られている。この場合に表面硬さの要求を満足する浸炭処理を行うと、組み立て時の溶接割れが生じやすくなり、要求特性を満足する鋼板及びその製造条件を得ることが困難となる。
【０００４】
加工性と焼き入れ性を改善する方法を開示したものとして特開平１０−２５９４４７号公報がある。この公報においては、焼き入れ性は質量％で１０％＜３０×Ｃ％＋５×Ｍｎ％＋６×Ｃｒ％＋３０×Ｂ％に、加工性は５％＞１０×Ｃ％＋Ｍｎ％＋１５０×Ｓを満足する成分に調整することにより得られることが開示されており、転造成型によるドライブプレート用鋼板として開発されている。しかし、この鋼板は衝撃性、溶接性が何ら考慮されておらず、上記の要求を満足しない。
【０００５】
【発明が解決しようとする課題】
そこで、本発明は、上記の加工性、焼き入れ後の表面の耐摩耗性と靭性を両立させ、かつ、溶接組み立てに必要な溶接時の割れをなくすることを満足するリクライナーギヤー用鋼板及びその製造方法の提供にある。
【０００６】
【課題を解決するための手段】
本発明者らは上記課題を解決すべく各種の検討を行った結果、本発明を完成した。
【０００７】
その要旨は以下の通りである。
【０００９】
（１） 質量％で、
Ｃ：０．２〜０．３５％、
Ｓｉ：０．２５％以下、
Ｍｎ：０．３５％以下、
Ｓ：０．００２〜０．０１５％、
Ｎｂ、Ｔｉの一種または二種の合計：０．０６５％以下、
残部がＦｅ及び不可避的不純物からなることを特徴とする加工性、焼き入れ性、溶接性の優れたリクライナーギヤー用鋼板。
【００１０】
（２） 質量％で、
Ｃ：０．２〜０．３５％、
Ｓｉ：０．２５％以下、
Ｍｎ：０．３５％以下、
Ｓ：０．００２〜０．０１５％、
Ｂ：０．０００５〜０．００５％、
Ｔｉ：０．０１〜０．０６５％、
残部がＦｅ及び不可避的不純物からなることを特徴とする加工性、焼き入れ性、溶接性の優れたリクライナーギヤー用鋼板。
【００１２】
（３） 質量％で、
Ｃ：０．２〜０．３５％、
Ｓｉ：０．２５％以下、
Ｍｎ：０．３５％以下、
Ｓ：０．００２〜０．０１５％、
Ｎｂ、Ｔｉの一種または二種の合計：０．０６５％以下、
残部がＦｅ及び不可避的不純物からなる鋼を熱間圧延するに際し、仕上げ温度をＡｒ3＋１０℃〜Ａｒ3＋５０℃、巻き取り温度を５５０℃〜７００℃で行い、引き続いて酸洗することを特徴とする加工性、焼き入れ性、溶接性の優れたリクライナーギヤー用鋼板の製造方法。
【００１３】
（４） 質量％で、
Ｃ：０．２〜０．３５％、
Ｓｉ：０．２５％以下、
Ｍｎ：０．３５％以下、
Ｓ：０．００２〜０．０１５％以下、
Ｂ：０．０００５〜０．００５％、
Ｔｉ：０．０１〜０．０６５％、
残部がＦｅ及び不可避的不純物からなる鋼を熱間圧延するに際し、仕上げ温度をＡｒ3＋１０℃〜Ａｒ3＋５０℃、巻き取り温度を５５０℃〜７００℃の範囲で行い、引き続いて酸洗することを特徴とする加工性、焼き入れ性、溶接性の優れたリクライナーギヤー用鋼板の製造方法。
【００１４】
（５） 酸洗後に焼鈍を施すことを特徴とする上記（３）または（４）の内の何れかに記載の加工性、焼き入れ性、溶接性の優れたリクライナーギヤー用鋼板の製造方法。
【００１５】
【発明の実施の形態】
以下本発明について詳細に説明する。
【００１６】
まず本発明を構成する鋼板の化学成分について説明する。
【００１７】
Ｃは焼き入れ後の表面硬さを確保するために、０．２％以上必要である。しかし、Ｃ量が高くなると溶接割れが生じやすくなり、同時に焼き入れが鋼板の中心部まで入り、成型部品の衝撃特性が悪くなる。この理由によりＣ量の上限を０．３５％に特定した。
【００１８】
Ｓｉは鋼板を硬質にする元素で、加工性の点からは少ないほうが好ましいが、０．０５％以下になるとリクライナーギヤーの疲労特性を低下させる。このため、０．０５％以上添加することが好ましい。しかし、添加量が０．２５％以上になると、鋼板の加工性を悪くするため上限を０．２５％に特定した。
【００１９】
Ｍｎは鋼板を硬くすると同時に焼き入れ性を高める元素として良く知られている。また、不可避的に混入するＳに起因する熱間脆性を防ぐためために必要な元素である。このため、０．１５％以上の添加が好ましい。しかし、添加量が０．３５％を超え、耐磨耗性に必要な炭素量を添加すると溶接時に割れが生じやすくなる。また、Ｍｎ量が高くなると、焼き入れ後の衝撃特性を劣化させる。以上の理由からＭｎ量を０．３５％以下に特定したが、０．１５〜０．３５％にすることが好ましい。
【００２０】
Ｓは一般に加工性を害する元素として知られているが、以下に説明する実験事実に基づき、焼き入れ後の衝撃特性を良好にするため、その量を特定した。真空溶解炉でＣ：０．３％、Ｍｎ：０．２５％、Ｓｉ：０．１５％、Ａｌ：０．０１％、及びＣ：０．３％、Ｍｎ：０．６％、Ｓｉ：０．１５％、Ａｌ：０．０１％をベースにＳ量を０．００１から０．０１８％に変えた鋼を溶製し、５．０ｍｍ厚の鋼板を造った。この鋼板を６９０℃×１４ｈｒの焼鈍後に、９５０℃加熱の高周波焼き入れを行ない、衝撃特性を調査した結果を図１に、表面硬さの調査結果を図２に示した。鋼板の表面硬さはＳ量が変化しても、ほとんど変化しないが、衝撃特性はＭｎ量、Ｓ量により、大きく変化し、Ｍｎ：０．６％材はＳ量に関係なく、衝撃特性が悪い。一方、Ｍｎ：０．２５％材ではＳ量が０．０１５％以上になると衝撃特性が悪くなるが、０．０１５％以下では優れた衝撃特性が得られる。この事実から、良好な衝撃特性を得るためにＳ量の上限を０．０１５％に特定した。下限は同じ理由から０．００２％以上にする必要がある。このようにＭｎ、Ｓの組み合わせにより焼き入れ後の衝撃特性の良好な鋼板が得られる。
【００２１】
Ｎｂ及びＴｉは本発明の重要な構成要件の一つである。より衝撃特性が必要なときにはＮｂ、Ｔｉの一種または二種の合計量のＮｂ＋Ｔｉを０．０６５％以内で添加する。Ｎｂ、Ｔｉは以下の実験事実に基づく知見より特定した。真空溶解炉でＣ：０．２８％、Ｓｉ：０．１５％、Ｍｎ：０．２５％、Ａｌ：０．０２％及びＣ：０．２８％、Ｓｉ：０．１５％、Ｍｎ：０．７８％、Ａｌ：０．０２５％の成分にそれぞれＴｉ、Ｎｂ量を変えて添加した鋼を溶製し、６．０ｍｍ厚みに熱延し、酸洗後に誘導加熱で９５０℃、１０５０℃に加熱、水冷し、鋼板のシャルピー衝撃試験を行った。０℃の吸収エネルギーと、Ｎｂ＋Ｔｉ量の関係を図３に示した。図から分かるように、Ｍｎ：０．２５％の鋼は全体に吸収エネルギーが高く、特にＴｉ、Ｎｂを添加することで向上する。焼き入れ加熱温度が高い条件ではＮｂ＋Ｔｉ量が０．０１５％を超えると吸収エネルギーが大幅に高くなる。この事実から、Ｎｂ＋Ｔｉ量は０．０１５％以上添加することが望ましい。一方、Ｎｂ＋Ｔｉ添加量が多くなりすぎると鋼板の加工性が低下するので、上限を０．０６５％に特定した。Ｍｎ：０．６８％添加した鋼はＮｂ、Ｔｉを添加しても衝撃特性が向上しなく、ベース成分を構成するＭｎ量と、Ｎｂ＋Ｔｉ添加の組み合わせにより、初めて、焼き入れままで高い衝撃特性が得られる。
【００２２】
Ｂは焼き入れ性を高める元素であることが良く知られている。本発明でもより焼き入れ性を特に必要とする場合に、Ｂを０．００５％以下の範囲で添加する。
下限は、焼き入れ性に有効に作用するに必要な０．０００５％である。
【００２３】
Ｂを添加した鋼では、このＢを焼き入れ性に有効に作用させるためにＴｉを添加するが、この目的のためにはＴｉ添加量は０．０１％以上必要となる。一方、添加量が多くなりすぎると加工性が劣化するため、その上限を０．０６５％とした。
【００２４】
Ａｌは脱酸材として用いられる元素で通常鋼中に含有され、酸化物系の介在物に起因する鋼の疲労強度の低下を防ぐため、０．０１％〜０．０５％程度含有していることが好ましい。
【００２５】
Ｐ、Ｎ等の不可避的に混入する元素は少ないほど加工性、衝撃特性を良好にするため、少なくすることが好ましい。
【００２６】
本発明の鋼の製造方法は、特に限定されるものではないが、以下の製造条件が望ましい。上記の組成の鋼は、通常の転炉、電気炉等で溶製され、必要に応じ真空脱ガス処理により溶製され、連続鋳造等により、スラブとされる。これらのスラブは熱間圧延に供されるが熱延の加熱温度が低くなると製品の衝撃特性を悪くするので、１０５０℃以上の加熱温度で行うことが好ましい。熱延仕上げ温度は鋼板の加工性と関係する。
【００２７】
仕上げ温度がＡｒ3点温度より、低くなると鋼板の加工性を損なうため、Ａｒ3点温度＋１０℃以上で行うのが望ましい。一方、熱延仕上げ温度が高くなりすぎると、やはり鋼板の加工性確保の点で望ましくない。このため、熱延仕上げ温度の上限はＡｒ3点温度＋５０℃が望ましい。
【００２８】
熱延後の巻き取り温度も比較的重要な要因である。巻き取り温度が高すぎると、加工性が劣化する傾向にあると共に、焼き入れ後の耐磨耗性を悪くする傾向にある。この理由から、巻き取り温度の上限は７００℃が好ましい。更に好ましい範囲は、同様の理由から６５０℃以下である。一方、巻き取り温度が低くなりすぎると鋼板の加工性が劣化する傾向にあるので、５５０℃以上とするのが望ましい。
【００２９】
このようにして熱延した鋼板は、脱スケールし、必要に応じ、調質圧延後に、あるいは焼鈍、調質圧延後にリクライナーギヤー鋼板に供される。脱スケール後に焼鈍する場合は、Ａｃ1点温度以下、６５０℃以上で実施している。
【００３０】
本発明の鋼は熱延後に酸洗、冷延、焼鈍の工程を経て製造されても、本発明の特徴を損なわないので、酸洗後に冷延、焼鈍してもかまわない。この場合、スケール後の冷間圧延は５０％以下の圧延率で行うのが普通である。焼鈍はＡｃ1点温度以下、６５０℃以上の温度で実施している。
【００３１】
このようにして製造された鋼板はリクライナーギヤー用鋼板として、優れた加工性と、熱処理後に高い耐磨耗性、耐溶接割れ性を兼備する。
【００３２】
【実施例】
表１に示す鋼組成のスラブを１２００℃加熱後、仕上げ温度が８６０〜８８０℃の仕上がり温度で４．５ｍｍ厚まで熱間圧延、６３０〜６５０℃の巻き取り温度で熱延コイルを造った。酸洗後、６９０℃×１８ｈｒの焼鈍後に、１．０％の調質圧延を行い鋼板を製造した。この鋼板を高周波焼き入れを行い、鋼板表面の硬さ及び、全厚のサブサイズのシャルピー試験片を用い、０℃で衝撃試験を行い吸収エネルギーを測定した。吸収エネルギーが５０Ｊ以上あれば良い。
【００３３】
また、これらの鋼板を用い、ラウンド型のリクライナーギヤーを造り、加工性を評価し、溶接組み立て、溶接部の割れの有無を調査した。加工性の評点はギヤー部の先端の割れの有無で評価し、溶接性は溶接部の割れの有無で評価し、割れあるいは微小クラックのあるものを×、ないものを○の評点とした。耐磨耗性の評価は表面硬さで評価し、ＨＶ≦５００を×、５０１〜５５０を△、５５１以上を○の評点とした。得られた特性を表２に示した。
【００３４】
【表１】
【表２】
Ｃが本発明範囲外のＮｏ．２、Ｍｎが本発明範囲外のＮｏ．４は溶接割れ性評点が悪く、しかも衝撃特性も劣っている。
【００３７】
また、Ｃが本発明範囲よりも低いＮｏ．１１は表面硬さが低く、耐摩耗性が劣っている。Ｎｏ．９はＭｎ量が低く耐摩耗性がやや劣る。
【００３８】
Ｎｏ．５、６、７、１２はＮｂ＋Ｔｉ、Ｔｉ＋Ｂ、Ｎｂ、Ｔｉを添加した本発明範囲の実施例である。いずれも、優れた加工性、耐磨耗性、衝撃特性、溶接性を有している。
【００３９】
Ｎｏ．８、１０は、Ｎｂ＋Ｔｉ添加材であるが、Ｃ、Ｍｎ量が発明範囲外の比較例で、いずれも溶接性、衝撃特性が劣っている。
【００４０】
Ｎｏ．１３、１４はＳが発明範囲外の鋼で、衝撃特性が劣る。
【００４１】
表３に示す製造条件で４．５ｍｍ厚の鋼板を製造した。鋼成分は表１の鋼Ｎｏ．に対応している。この鋼板を高周波焼き入れを行い、鋼板表面の硬さ及び、全厚のサブサイズのシャルピー試験片を用い、０℃で衝撃試験を行い吸収エネルギーを測定した。また、これらの鋼板を用い、ラウンド型のリクライナーギヤーを造り、加工性を評価し、溶接組み立て、溶接部の割れの有無を調査した。加工性の評点はギヤー部の先端の割れの有無で評価し、溶接性は溶接部の割れの有無で評価し、割れあるいは微小クラックのあるものを×、ないものを○の評点とした。なお、ギヤーの刃先に割れが観察されたものは、溶接組み立てを行わなかった。
【００４３】
Ｎｏ．５−１、５−２は、Ｎｂ＋Ｔｉを添加した実施例である。請求項の範囲の製造条件であり、いずれの特性も優れている。
【００４４】
Ｎｏ．６−１、６−２はＴｉとＢを添加した実施例である。請求項の範囲のＮｏ．６−１、６−２は優れたリクライナーギヤー用鋼板としての特性を有する。
【００４５】
【表３】
【表４】
【発明の効果】
以上の実施例で詳細に説明したように、鋼成分を特定することで、溶接組み立てするラウンド型リクライナーギヤー用鋼板として、優れた特性を発揮することが分かる。すなわち、ファインブランキング加工時に、モジュールの小さなギヤーでも割れを生じることなく成型できる優れた加工性を有し、焼き入れ後に衝撃特性、耐磨耗性の優れた特性を発揮する。しかも、溶接組み立てでも割れが生じない鋼板を提供できる。
【図面の簡単な説明】
【図１】Ｓ量と高周波の焼き入れ後の０℃での衝撃試験での吸収エネルギーの関係を示す図である。
【図２】Ｓ量と高周波焼き入れ後の鋼板の表面硬さ（Ｈｖ）の関係を示す図である。
【図３】Ｔｉ＋Ｎｂ添加量と高周波焼き入れ後の０℃での衝撃試験の吸収エネルギーの関係を示す図である。[0001]
BACKGROUND OF THE INVENTION
A steel plate for a recliner gear excellent in workability, hardenability and weldability suitable for manufacturing a gear part used by being incorporated in an arm pole used for adjusting the angle of a recliner sheet of an automobile, and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, gear parts incorporated in an arm pole of a recliner of an automobile have been manufactured by molding a gear by half blanking with fine blanking using S45C and fixing by bolting. In recent years, miniaturization of gears and smoothness of movement have demanded smaller gears, and demands for workability have become stricter. Moreover, cost reduction and downsizing are being promoted by assembly by welding from the conventional assembly method by bolt fixing.
[0003]
The characteristics required for the steel sheet used in this welding assembly method are that the surface hardness is Hv: 500 or more from the point of wear resistance, weld cracking does not occur, and workability required for gear molding of small modules is required. ing. In addition, impact characteristics that can withstand impact loads are required. The surface hardness becomes better as the hardenability of the steel sheet is improved, in other words, the higher the amount of carbon, the amount of alloy elements such as Mn, Cr, and Mo is higher. On the other hand, the weld cracking property becomes better as the amount of carbon, the number of alloy elements such as Mn, Cr, and Mo decreases. In general, the impact characteristics deteriorate as the hardness increases, and when the alloy element amount is large, the quenching hardness increases and the impact characteristics also decrease. In order to avoid this deterioration of impact characteristics, a method of carburizing and quenching a low carbon steel sheet has been studied, and it is known that a sufficient amount of carburization needs to be ensured in order to obtain sufficient surface hardness. Yes. In this case, if carburizing treatment that satisfies the requirements for surface hardness is performed, weld cracking during assembly is likely to occur, making it difficult to obtain a steel sheet that satisfies the required characteristics and its manufacturing conditions.
[0004]
Japanese Patent Laid-Open No. 10-259447 discloses a method for improving workability and hardenability. In this publication, the hardenability satisfies 10% <30 × C% + 5 × Mn% + 6 × Cr% + 30 × B% by mass%, and the workability satisfies 5%> 10 × C% + Mn% + 150 × S. It is disclosed that it can be obtained by adjusting to the component to be used, and has been developed as a steel plate for drive plates by rolling. However, this steel sheet does not consider any impact and weldability and does not satisfy the above requirements.
[0005]
[Problems to be solved by the invention]
Accordingly, the present invention provides a steel plate for a recliner gear that satisfies both the workability, the wear resistance and toughness of the surface after quenching, and satisfies the requirement of eliminating cracks during welding necessary for welding assembly, and Providing a manufacturing method.
[0006]
[Means for Solving the Problems]
As a result of various studies to solve the above problems, the present inventors have completed the present invention.
[0007]
The summary is as follows.
[0009]
( 1 ) In mass%,
C: 0.2 to 0.35%,
Si: 0.25% or less,
Mn: 0.35% or less,
S: 0.002 to 0.015%,
Total of one or two of Nb and Ti: 0.065% or less,
A steel plate for a recliner gear having excellent workability, hardenability, and weldability, wherein the balance is Fe and inevitable impurities.
[0010]
( 2 ) In mass%,
C: 0.2 to 0.35%,
Si: 0.25% or less,
Mn: 0.35% or less,
S: 0.002 to 0.015%,
B: 0.0005 to 0.005%,
Ti: 0.01 to 0.065%,
A steel plate for a recliner gear having excellent workability, hardenability, and weldability, wherein the balance is Fe and inevitable impurities.
[0012]
( 3 ) In mass%,
C: 0.2 to 0.35%,
Si: 0.25% or less,
Mn: 0.35% or less,
S: 0.002 to 0.015%,
Total of one or two of Nb and Ti: 0.065% or less,
When hot-rolling steel comprising the balance Fe and inevitable impurities, the finishing temperature is Ar 3 + 10 ° C. to Ar 3 + 50 ° C., the coiling temperature is 550 ° C. to 700 ° C., and then pickling is performed. The manufacturing method of the steel plate for recliner gears which is excellent in workability, hardenability, and weldability.
[0013]
( 4 ) In mass%,
C: 0.2 to 0.35%,
Si: 0.25% or less,
Mn: 0.35% or less,
S: 0.002 to 0.015% or less,
B: 0.0005 to 0.005%,
Ti: 0.01 to 0.065%,
When hot-rolling steel comprising the balance Fe and inevitable impurities, the finishing temperature is Ar 3 + 10 ° C. to Ar 3 + 50 ° C., the coiling temperature is 550 ° C. to 700 ° C., and then pickling is performed. The manufacturing method of the steel plate for recliner gears which is excellent in workability, hardenability, and weldability.
[0014]
( 5 ) The method for producing a steel sheet for a recliner gear having excellent workability, hardenability and weldability according to any one of (3) and (4) , wherein annealing is performed after pickling.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
[0016]
First, the chemical components of the steel sheet constituting the present invention will be described.
[0017]
C needs to be 0.2% or more in order to ensure the surface hardness after quenching. However, if the amount of C increases, weld cracks are likely to occur, and at the same time, quenching enters the center of the steel sheet, resulting in poor impact characteristics of the molded part. For this reason, the upper limit of the C content is specified to be 0.35%.
[0018]
Si is an element that hardens the steel sheet and is preferably less in terms of workability. However, when it is 0.05% or less, the fatigue characteristics of the recliner gear are lowered. For this reason, it is preferable to add 0.05% or more. However, when the addition amount is 0.25% or more, the upper limit is specified as 0.25% in order to deteriorate the workability of the steel sheet.
[0019]
Mn is well known as an element that hardens the steel sheet and at the same time enhances the hardenability. Further, it is an element necessary for preventing hot brittleness caused by S inevitably mixed. For this reason, addition of 0.15% or more is preferable. However, if the addition amount exceeds 0.35% and the carbon amount necessary for wear resistance is added, cracking is likely to occur during welding. Moreover, when the amount of Mn becomes high, the impact characteristics after quenching are deteriorated. For the above reasons, the amount of Mn is specified to be 0.35% or less, but is preferably 0.15 to 0.35%.
[0020]
S is generally known as an element that impairs workability, but based on the experimental facts described below, the amount was specified in order to improve the impact characteristics after quenching. In a vacuum melting furnace, C: 0.3%, Mn: 0.25%, Si: 0.15%, Al: 0.01%, and C: 0.3%, Mn: 0.6%, Si: 0 A steel having an S content of 0.001 to 0.018% based on 0.1% Al and 0.01% was melted to produce a 5.0 mm thick steel plate. This steel sheet was annealed at 690 ° C. × 14 hr, and then subjected to induction hardening at 950 ° C., and the impact characteristics were investigated. FIG. 1 shows the results of the surface hardness, and FIG. Although the surface hardness of the steel sheet hardly changes even when the S content changes, the impact characteristics vary greatly depending on the Mn content and the S content. The Mn: 0.6% material has impact characteristics regardless of the S content. bad. On the other hand, when the amount of S is 0.015% or more in the case of Mn: 0.25% material, the impact characteristics are deteriorated, but when it is 0.015% or less, excellent impact characteristics are obtained. From this fact, the upper limit of the amount of S was specified to be 0.015% in order to obtain good impact characteristics. The lower limit needs to be 0.002% or more for the same reason. Thus, a steel plate with good impact characteristics after quenching can be obtained by the combination of Mn and S.
[0021]
Nb and Ti are one of the important constituent elements of the present invention. When more impact characteristics are required, Nb + Ti in a total amount of one or two of Nb and Ti is added within 0.065%. Nb and Ti were specified from the findings based on the following experimental facts. In a vacuum melting furnace, C: 0.28%, Si: 0.15%, Mn: 0.25%, Al: 0.02% and C: 0.28%, Si: 0.15%, Mn: 0.00. Steel with 78% and Al: 0.025% components added with different Ti and Nb amounts is melted, hot rolled to a thickness of 6.0 mm, heated to 950 ° C. and 1050 ° C. by induction heating after pickling. The steel sheet was cooled with water, and a Charpy impact test was performed on the steel sheet. The relationship between the absorbed energy at 0 ° C. and the amount of Nb + Ti is shown in FIG. As can be seen from the figure, steel with Mn: 0.25% has a high absorbed energy as a whole, and is improved by adding Ti and Nb in particular. Under conditions where the quenching heating temperature is high, the absorbed energy is significantly increased when the amount of Nb + Ti exceeds 0.015%. From this fact, it is desirable to add Nb + Ti amount of 0.015% or more. On the other hand, if the Nb + Ti addition amount is too large, the workability of the steel sheet is lowered, so the upper limit was specified as 0.065%. Steel with Mn: 0.68% added does not improve impact characteristics even when Nb and Ti are added. For the first time, the combination of the amount of Mn constituting the base component and the addition of Nb + Ti has high impact characteristics as-quenched. can get.
[0022]
It is well known that B is an element that enhances hardenability. In the present invention, when hardenability is particularly required, B is added in a range of 0.005% or less.
The lower limit is 0.0005% which is necessary to effectively act on the hardenability.
[0023]
In the steel to which B is added, Ti is added in order to make this B act effectively on the hardenability. For this purpose, the Ti addition amount is required to be 0.01% or more. On the other hand, if the amount added is too large, the workability deteriorates, so the upper limit was made 0.065%.
[0024]
Al is an element used as a deoxidizer and is usually contained in steel, and is contained in an amount of about 0.01% to 0.05% in order to prevent a decrease in fatigue strength of the steel due to oxide inclusions. It is preferable.
[0025]
The smaller the elements inevitably mixed in such as P and N, the better the workability and impact characteristics.
[0026]
Although the manufacturing method of the steel of this invention is not specifically limited, The following manufacturing conditions are desirable. The steel having the above composition is melted in a normal converter, electric furnace or the like, melted by vacuum degassing treatment as necessary, and made into a slab by continuous casting or the like. These slabs are subjected to hot rolling, but if the heating temperature of hot rolling is lowered, the impact characteristics of the product are deteriorated, so that it is preferable to carry out at a heating temperature of 1050 ° C. or higher. The hot rolling finish temperature is related to the workability of the steel sheet.
[0027]
Since the workability of the steel sheet is impaired when the finishing temperature is lower than the Ar 3 point temperature, it is desirable to carry out at an Ar 3 point temperature of + 10 ° C. or higher. On the other hand, if the hot rolling finishing temperature becomes too high, it is also undesirable from the viewpoint of securing the workability of the steel sheet. For this reason, the upper limit of the hot rolling finishing temperature is preferably Ar 3 point temperature + 50 ° C.
[0028]
The coiling temperature after hot rolling is also a relatively important factor. If the winding temperature is too high, the workability tends to deteriorate and the wear resistance after quenching tends to deteriorate. For this reason, the upper limit of the winding temperature is preferably 700 ° C. A more preferable range is 650 ° C. or lower for the same reason. On the other hand, if the coiling temperature is too low, the workability of the steel sheet tends to deteriorate, so it is desirable that the temperature be 550 ° C. or higher.
[0029]
The steel sheet thus hot-rolled is descaled and, if necessary, provided to the recliner gear steel sheet after temper rolling, or after annealing and temper rolling. In the case of annealing after descaling, it is carried out at an Ac 1 point temperature or lower and 650 ° C. or higher.
[0030]
Even if the steel of the present invention is manufactured through steps of pickling, cold rolling, and annealing after hot rolling, the characteristics of the present invention are not impaired, and therefore, it may be cold rolled and annealed after pickling. In this case, the cold rolling after the scale is usually performed at a rolling rate of 50% or less. Annealing is performed at a temperature of Ac 1 point or lower and 650 ° C. or higher.
[0031]
The steel plate produced in this way has excellent workability, high wear resistance after heat treatment, and weld crack resistance as a recliner gear steel plate.
[0032]
【Example】
A slab having a steel composition shown in Table 1 was heated at 1200 ° C., then hot rolled to a thickness of 4.5 mm at a finishing temperature of 860 to 880 ° C., and a hot rolled coil was made at a winding temperature of 630 to 650 ° C. After pickling, after annealing at 690 ° C. × 18 hr, 1.0% temper rolling was performed to produce a steel sheet. This steel plate was induction-hardened, and the absorbed energy was measured by performing an impact test at 0 ° C. using a Charpy test piece of the steel plate surface hardness and full thickness. It is sufficient if the absorbed energy is 50 J or more.
[0033]
In addition, using these steel plates, round type recliner gears were made, workability was evaluated, and welding assembly and the presence or absence of cracks in the welds were investigated. The score of workability was evaluated based on the presence or absence of cracks at the tip of the gear part, and the weldability was evaluated based on the presence or absence of cracks in the welded part. Evaluation of abrasion resistance was evaluated by surface hardness, and HV ≦ 500 was evaluated as x, 501 to 550 as Δ, and 551 or higher as ○. The obtained characteristics are shown in Table 2.
[0034]
[Table 1]
[Table 2]
No. C is outside the scope of the present invention. 2, Mn is No. out of the scope of the present invention. No. 4 has a poor weld cracking score and inferior impact properties.
[0037]
Moreover, No. C is lower than the scope of the present invention. 11 has low surface hardness and inferior wear resistance. No. No. 9 has a low amount of Mn and is slightly inferior in wear resistance.
[0038]
No. 5, 6, 7, and 12 are examples within the scope of the present invention in which Nb + Ti, Ti + B, Nb, and Ti are added. All have excellent workability, wear resistance, impact characteristics, and weldability .
[0039]
No. Nos. 8 and 10 are Nb + Ti additives, but the C and Mn amounts are comparative examples outside the scope of the invention, and both have poor weldability and impact characteristics.
[0040]
No. 13 and 14 are steels in which S is outside the scope of the invention, and the impact characteristics are poor.
[0041]
A steel sheet having a thickness of 4.5 mm was manufactured under the manufacturing conditions shown in Table 3. The steel composition is steel No. 1 in Table 1. It corresponds to. This steel plate was induction-hardened, and the absorbed energy was measured by performing an impact test at 0 ° C. using a Charpy test piece of the steel plate surface hardness and full thickness. In addition, using these steel plates, round type recliner gears were made, workability was evaluated, and welding assembly and the presence or absence of cracks in the welds were investigated. The score of workability was evaluated based on the presence or absence of cracks at the tip of the gear part, and the weldability was evaluated based on the presence or absence of cracks in the welded part. In addition, the thing in which the crack was observed in the blade edge of the gear was not welded.
[0043]
No. 5-1 and 5-2 are examples in which Nb + Ti is added. The manufacturing conditions are within the scope of the claims, and all the characteristics are excellent.
[0044]
No. 6-1 and 6-2 are examples in which Ti and B are added. No. in the scope of claims. 6-1 and 6-2 have excellent properties as a steel sheet for re Kleiner gear.
[0045]
[Table 3]
[Table 4]
【The invention's effect】
As described in detail in the above examples, it can be seen that, by specifying the steel components, the steel plate for round type recliner gear to be welded and assembled exhibits excellent characteristics. In other words, it has excellent processability that can be molded without cracking even with a small gear of the module at the time of fine blanking, and exhibits excellent characteristics of impact properties and wear resistance after quenching. Moreover, it is possible to provide a steel plate that does not crack even in welding assembly.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the amount of S and absorbed energy in an impact test at 0 ° C. after high-frequency quenching.
FIG. 2 is a graph showing the relationship between the amount of S and the surface hardness (Hv) of a steel plate after induction hardening.
FIG. 3 is a diagram showing the relationship between the amount of Ti + Nb added and the energy absorbed in an impact test at 0 ° C. after induction hardening.
Claims (5)
Ｃ：０．２〜０．３５％、
Ｓｉ：０．２５％以下、
Ｍｎ：０．３５％以下、
Ｓ：０．００２〜０．０１５％、
Ｎｂ、Ｔｉの一種または二種の合計：０．０６５％以下、
残部がＦｅ及び不可避的不純物からなることを特徴とする加工性、焼き入れ性、溶接性の優れたリクライナーギヤー用鋼板。% By mass
C: 0.2 to 0.35%,
Si: 0.25% or less,
Mn: 0.35% or less,
S: 0.002 to 0.015%,
Total of one or two of Nb and Ti: 0.065% or less,
A steel plate for a recliner gear having excellent workability, hardenability, and weldability, wherein the balance is Fe and inevitable impurities.
Ｃ：０．２〜０．３５％、
Ｓｉ：０．２５％以下、
Ｍｎ：０．３５％以下、
Ｓ：０．００２〜０．０１５％、
Ｂ：０．０００５〜０．００５％、
Ｔｉ：０．０１〜０．０６５％、
残部がＦｅ及び不可避的不純物からなることを特徴とする加工性、焼き入れ性、溶接性の優れたリクライナーギヤー用鋼板。% By mass
C: 0.2 to 0.35%,
Si: 0.25% or less,
Mn: 0.35% or less,
S: 0.002 to 0.015%,
B: 0.0005 to 0.005%,
Ti: 0.01 to 0.065%,
A steel plate for a recliner gear having excellent workability, hardenability, and weldability, wherein the balance is Fe and inevitable impurities.
Ｃ：０．２〜０．３５％、
Ｓｉ：０．２５％以下、
Ｍｎ：０．３５％以下、
Ｓ：０．００２〜０．０１５％、
Ｎｂ、Ｔｉの一種または二種の合計：０．０６５％以下、
残部がＦｅ及び不可避的不純物からなる鋼を熱間圧延するに際し、仕上げ温度をＡｒ3＋１０℃〜Ａｒ3＋５０℃、巻き取り温度を５５０℃〜７００℃で行い、引き続いて酸洗することを特徴とする加工性、焼き入れ性、溶接性の優れたリクライナーギヤー用鋼板の製造方法。% By mass
C: 0.2 to 0.35%,
Si: 0.25% or less,
Mn: 0.35% or less,
S: 0.002 to 0.015%,
Total of one or two of Nb and Ti: 0.065% or less,
When hot-rolling steel comprising the balance Fe and inevitable impurities, the finishing temperature is Ar 3 + 10 ° C. to Ar 3 + 50 ° C., the coiling temperature is 550 ° C. to 700 ° C., and then pickling is performed. The manufacturing method of the steel plate for recliner gears which is excellent in workability, hardenability, and weldability.
Ｃ：０．２〜０．３５％、
Ｓｉ：０．２５％以下、
Ｍｎ：０．３５％以下、
Ｓ：０．００２〜０．０１５％以下、
Ｂ：０．０００５〜０．００５％、
Ｔｉ：０．０１〜０．０６５％、
残部がＦｅ及び不可避的不純物からなる鋼を熱間圧延するに際し、仕上げ温度をＡｒ3＋１０℃〜Ａｒ3＋５０℃、巻き取り温度を５５０℃〜７００℃の範囲で行い、引き続いて酸洗することを特徴とする加工性、焼き入れ性、溶接性の優れたリクライナーギヤー用鋼板の製造方法。% By mass
C: 0.2 to 0.35%,
Si: 0.25% or less,
Mn: 0.35% or less,
S: 0.002 to 0.015% or less,
B: 0.0005 to 0.005%,
Ti: 0.01 to 0.065%,
When hot-rolling steel comprising the balance Fe and inevitable impurities, the finishing temperature is Ar 3 + 10 ° C. to Ar 3 + 50 ° C., the coiling temperature is 550 ° C. to 700 ° C., and then pickling is performed. The manufacturing method of the steel plate for recliner gears which is excellent in workability, hardenability, and weldability.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001120204A JP4025515B2 (en) | 2001-04-18 | 2001-04-18 | Steel plate for recliner gear with excellent workability, hardenability and weldability, and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001120204A JP4025515B2 (en) | 2001-04-18 | 2001-04-18 | Steel plate for recliner gear with excellent workability, hardenability and weldability, and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002317240A JP2002317240A (en) | 2002-10-31 |
| JP4025515B2 true JP4025515B2 (en) | 2007-12-19 |
Family
ID=18970289
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001120204A Expired - Fee Related JP4025515B2 (en) | 2001-04-18 | 2001-04-18 | Steel plate for recliner gear with excellent workability, hardenability and weldability, and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4025515B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5375916B2 (en) * | 2011-09-28 | 2013-12-25 | Ｊｆｅスチール株式会社 | Manufacturing method of wear-resistant steel plate with excellent flatness |
-
2001
- 2001-04-18 JP JP2001120204A patent/JP4025515B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2002317240A (en) | 2002-10-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3854506B2 (en) | High strength steel plate excellent in weldability, hole expansibility and ductility, and manufacturing method thereof | |
| EP2692889B1 (en) | Ferritic stainless steel sheet having excellent heat resistance and processability, and method for producing same | |
| JP5846311B2 (en) | Thick high-strength steel excellent in welding heat affected zone CTOD characteristics and method for producing the same | |
| JP3704306B2 (en) | Hot-dip galvanized high-strength steel sheet excellent in weldability, hole expansibility and corrosion resistance, and method for producing the same | |
| JP5825481B2 (en) | High-strength cold-rolled steel sheet excellent in deep drawability and bake hardenability and its manufacturing method | |
| JP4238832B2 (en) | Abrasion-resistant steel plate and method for producing the same | |
| JP5045074B2 (en) | High tensile thin-walled steel sheet having low yield ratio and manufacturing method thereof | |
| JP4207334B2 (en) | High-strength steel sheet with excellent weldability and stress corrosion cracking resistance and method for producing the same | |
| JP5034290B2 (en) | Low yield ratio high strength thick steel plate and method for producing the same | |
| JP4379085B2 (en) | Manufacturing method of high strength and high toughness thick steel plate | |
| JP4676923B2 (en) | High strength and high ductility hot dip galvanized steel sheet excellent in corrosion resistance and welding strength and method for producing the same | |
| JP5157257B2 (en) | Low yield ratio steel sheet | |
| CN109804092B (en) | Cold-rolled steel sheet for flux-cored wire and method for manufacturing same | |
| JP3895986B2 (en) | High-strength steel plate excellent in weldability and hole expansibility and method for producing the same | |
| JP4513552B2 (en) | High-tensile hot-rolled steel sheet excellent in bake hardenability and room temperature aging resistance and method for producing the same | |
| JPH06145894A (en) | High strength hot rolled steel sheet excellent in ductility and delayed fracture resistance and its production | |
| JP3970801B2 (en) | High strength high toughness steel plate | |
| JP4061229B2 (en) | High carbon steel sheet excellent in workability, hardenability, weldability, carburization resistance and decarburization resistance, and manufacturing method thereof | |
| KR101949025B1 (en) | Cold rolled steel sheet for flux cored wire and method of manufacturing the same | |
| JP3858647B2 (en) | High strength steel excellent in low temperature joint toughness and SSC resistance and method for producing the same | |
| JP4025515B2 (en) | Steel plate for recliner gear with excellent workability, hardenability and weldability, and method for producing the same | |
| JP4580403B2 (en) | Hot-dip hot-dip steel sheet for deep drawing and method for producing the same | |
| JP4055920B2 (en) | Manufacturing method of high strength steel pipe for hollow stabilizer with excellent fatigue durability | |
| JP4655372B2 (en) | Method for producing high-tensile steel with high yield point | |
| JP5151510B2 (en) | Manufacturing method of high strength steel with excellent low temperature toughness and crack propagation stop properties |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20050915 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20070426 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20070522 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20070718 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20071002 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20071005 |
|
| R151 | Written notification of patent or utility model registration |
Ref document number: 4025515 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R151 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101012 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101012 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111012 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111012 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121012 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121012 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20131012 Year of fee payment: 6 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20131012 Year of fee payment: 6 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20131012 Year of fee payment: 6 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| LAPS | Cancellation because of no payment of annual fees |