JP2004043832A - Stock for magnetic shielding for color picture tube, method of producing the same, magnetic shielding material for color picture tube and color picture tube - Google Patents
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Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、カラー受像管用の磁気シールド用素材に関し、優れた内部磁気シールド特性を有するとともに、優れたハンドリング強度を有するカラー受像管用の磁気シールド用素材及びその製造方法に関する。
【０００２】
【従来の技術】
カラーテレビなどのカラー受像管は基本的に電子銃と電子ビームを映像に換える蛍光面から構成されており、さらに受像管内部は、電子ビームが地磁気により移動されることを緩和するために、磁気シールド材で被覆されている。
この磁気シールド材の素材として用いられる鋼板においては、地磁気ドリフト量が小さいことなどの磁気的特性に加えて、折り曲げ加工などの成形加工性が良好であること、加工前、あるいは加工された磁気シールド材を搬送する際、あるいは、被加工材を積み重ねる際に変形を生じない程度のハンドリング強度を有していることなどの機械的特性が必要とされている。
【０００３】
地磁気ドリフト量が小さくなるような素材は、従来の考えは、磁壁の移動を阻害する鋼中の炭素、窒素を極少にし、結晶粒径大にする必要があった。本発明は、さらに、Ａｌ添加量を低減させ、ＡｌＮの析出を低減させ、結晶粒の粗大化を図った。または、Ａｌを多く添加した場合は、ＡｌよりＮとの親和力の高いＢを添加させることで、結晶粒の粗大化を図った。これはＡｌＮより、ＢＮの方が、析出物サイズが大きいが、析出個数が少ないため、ＡｌＮによる結晶粒の細粒化を抑制できる効果を利用したものである。
また、ユーザーの用途によっては、鋼板の圧延方向に対する磁気の異方性が望まれることがあり、この場合、焼鈍中の架張を大きく、また、調質圧延を施す。以上、望まれる特性の定義とその範囲を示す。 鋼板は磁化されやすい特性を有することが望まれ、そのパラメータとして、残留磁束密度（以下、Ｂｒで示す、単位：Ｔ）と保磁力（以下、Ｈｃで示す、単位：Ａ／ｍ）の比：Ｂｒ／Ｈｃ（単位：Ｔ・ｍ／Ａ）を６．０以上、望ましくは、１０．０以上とすることが望ましい。
また、インナーシールドが、展張力タイプのシャドウマスクともに使用される場合は、鋼板の圧延方向と直角方向に磁気の異方性が大きいことがより望ましく、そのパラメータとして、磁気異方性は、 磁気異方性＝（圧延平行方向での残留磁束密度（Ｂｒ平行）／保磁力（Ｈｃ平行））／（圧延直角方向での残留磁束密度（Ｂｒ直角）／保磁力（Ｈｃ直角））、または、この逆数で、いずれかの大きな値
と定義し、この磁気異方性が、１．３以上、望ましくは、１．５以上であることがより望ましい。また、加工性、ハンドリング強度の点からは、鋼中の炭素、窒素を減少させ結晶粒径を大にすると、鋼板の強度が低下し、折り曲げ加工などの成形加工性は向上するが、鋼板や折り曲げ加工を施された被加工材を搬送する際に、軽度の衝撃により凹凸を生じたり、あるいは、被加工材を積み重ねた際に重みにより被加工材が変形したりしやすくなる。上記の相反する優れた磁気特性と優れたハンドリング強度を同時に満足させる必要があり、その点から、機械強度（抗張力：以下、ＴＳでしめす）は２５０〜５００ＭＰａであることである。
【０００４】
従来、磁気シールド特性を有する材料としては、優れたハンドリング強度を有し、かつ軟磁性の珪素鋼板、または、極低炭素鋼板があるが、前者はカラー受像管に必要とされる黒化処理が困難であるために使用された例がない。また、後者は結晶粒が粗大であり、磁気シールド特性には優れているが、十分なハンドリング強度を有するものは得られていない。
【０００５】
【発明が解決しようとする課題】
本発明は、Ｂｒ／Ｈｃが６．０以上、望ましくは、１０．０以上を有し、かつ、磁気異方性が１．３以上と優れた磁気特性である。これらいずれかの磁気特性が優れているかは、ブラウン管のユーザーにより、異なる。さらに、ＴＳ＝２５０〜５００ＭＰａと優れたハンドリング強度を有するカラー受像管用の磁気シールド用素材を提供することを課題としている。
【０００６】
【問題を解決するための手段】
請求項１記載のカラー受像管用磁気シールド用素材は、Ｃ：０．０１０重量％以下、Ｓｉ：０．０３重量％以下、Ｍｎ：０．２１重量％未満、Ｐ：１．０重量％以下、Ｓ：０．０３０重量％以下、Ａｌ：０．００５重量％以下、Ｎ：０．００７重量％以下を含み、残部がＦｅおよび不可避的不純物の鋼板からなることを特徴とする。
請求項２記載のカラー受像管用磁気シールド用素材は、Ｃ：０．０１０重量％以下、Ｓｉ：０．０３重量％以下、Ｍｎ：０．４０重量％以下、Ｐ：１．０重量％以下、Ｓ：０．０３０重量％以下、Ａｌ：０．０１０重量％以下、Ｎ：０．００７重量％以下、Ｂ：０．００１〜０．００３重量％を含み、残部がＦｅおよび不可避的不純物の鋼板からなることを特徴とする。
請求項３記載のカラー受像管用磁気シールド用素材は、Ｃ：０．０１０重量％以下、Ｓｉ：０．０３重量％以下、Ｍｎ：０．２１重量％未満、Ｐ：１．０重量％以下、Ｓ：０．０３０重量％以下、Ａｌ：０．００５重量％以下、Ｎ：０．００７重量％以下を含み、残部がＦｅおよび不可避的不純物の鋼板の表面に、Ｃｒめっき層、Ｎｉめっき層あるいはＦｅ−Ｎｉ拡散層を有することを特徴とする。請求項４記載のカラー受像管用磁気シールド用素材は、Ｃ：０．０１０重量％以下、Ｓｉ：０．０３重量％以下、Ｍｎ：０．４０重量％以下、Ｐ：１．０重量％以下、Ｓ：０．０３０重量％以下、Ａｌ：０．０１０重量％以下、Ｎ：０．００７重量％以下、Ｂ：０．００１〜０．００３重量％を含み、残部がＦｅおよび不可避的不純物の鋼板の表面に、Ｃｒめっき層、Ｎｉめっき層あるいはＦｅ−Ｎｉ拡散層を有することを特徴とする。
請求項５に記載のカラー受像管用磁気シールド用素材の製造方法は、Ｃ：０．０１０重量％以下、Ｓｉ：０．０３重量％以下、Ｍｎ：０．２１重量％未満、Ｐ：１．０重量％以下、Ｓ：０．０３０重量％以下、Ａｌ：０．００５重量％以下、Ｎ：０．００７重量％以下を含み、残部がＦｅおよび不可避的不純物の鋼板鋼板に、冷間圧延を施し、６７０℃以上の温度で連続焼鈍を行った後、ＣｒめっきあるいはＮｉめっきを施すことを特徴とする。
請求項６に記載のカラー受像管用磁気シールド用素材の製造方法は、Ｃ：０．０１０重量％以下、Ｓｉ：０．０３重量％以下、Ｍｎ：０．４０重量％以下、Ｐ：１．０重量％以下、Ｓ：０．０３０重量％以下、Ａｌ：０．０１０重量％以下、Ｎ：０．００７重量％以下、Ｂ：０．００１〜０．００３重量％を含み、残部がＦｅおよび不可避的不純物の鋼板に、冷間圧延を施し、７００℃以上の温度で連続焼鈍を行った後、ＣｒめっきあるいはＮｉめっきを施すことを特徴とする。請求項７に記載のカラー受像管用の磁気シールド用素材の製造方法は、Ｃ：０．０１０重量％以下、Ｓｉ：０．０３重量％以下、Ｍｎ：０．２１重量％未満、Ｐ：１．０重量％以下、Ｓ：０．０３０重量％以下、Ａｌ：０．００５重量％以下、Ｎ：０．００７重量％以下を含み、残部がＦｅおよび不可避的不純物の鋼板鋼板に、冷間圧延を施し、６７０℃以上の温度で連続焼鈍を行い、伸び率５％以下の調質圧延を施した後、ＣｒめっきあるいはＮｉめっきを施すことを特徴とする。
請求項８に記載のカラー受像管用磁気シールド用素材の製造方法は、Ｃ：０．０１０重量％以下、Ｓｉ：０．０３重量％以下、Ｍｎ：０．４０重量％以下、Ｐ：１．０重量％以下、Ｓ：０．０３０重量％以下、Ａｌ：０．０１０重量％以下、Ｎ：０．００７重量％以下、Ｂ：０．００１〜０．００３重量％を含み、残部がＦｅおよび不可避的不純物の鋼板に、冷間圧延を施し、７００℃以上の温度で連続焼鈍を行い、伸び率５％以下の調質圧延を施した後、ＣｒめっきあるいはＮｉめっきを施すことを特徴とする。
請求項９に記載のカラー受像管用磁気シールド材は、請求項１乃至４のいずれかに記載のカラー受像管用磁気シールド用素材を用いて作製したカラー受像管用磁気シールド材である。
請求項１０に記載のカラー受像管用磁気シールド材は、請求項５乃至８のいずれかに記載のカラー受像管用の磁気シールド用素材の製造方法を用いて作製したカラー受像管用磁気シールド材である。
請求項１１に記載のカラー受像管は、請求項９乃至１０のいずれかに記載のカラー受像管用磁気シールド材を用いて作製したカラー受像管である。
【０００７】
【発明の実施の形態】
本発明においては、極低炭素鋼を冷間圧延し、請求項１の成分系の場合、６７０℃以上、請求項２の成分系の場合は、７００℃以上の温度で連続焼鈍し、必要により、調質圧延を施し、Ｂｒ／Ｈｃが６．０以上、望ましくは、１０．０以上を有し、かつ、磁気異方性が１．３以上、望ましくは、１．５以上と優れた磁気特性であり、さらに、Ｔ．Ｓ．：２５０〜５００ＭＰａと優れたハンドリング強度の優れたカラー受像管用の磁気シールド用素材が得られることが判明した。
【０００８】
以下、本発明を実施例により、詳細に説明する。
本発明のカラー受像管用の磁気シールド用素材に用いる極低炭素鋼としては、真空脱ガス法を用いて脱炭し、および、脱窒を行い、熱延および連続焼鈍の工程で、結晶粒度ＡＳＴＭ Ｎｏ．５．０〜７．５になるように請求項１の鋼成分の場合は、６７０℃以上、、請求項２の鋼成分の場合は７００℃以上で焼鈍する。また、鋼板に優れた磁気異方性を持たせるために、連続焼鈍中は鋼板を９Ｎ／ｍｍ２以上の張力で架張した方が望ましい。
さらに、鋼中に微細分散している過度の炭化物および窒化物は磁壁の移動を妨げ磁気特性を劣化させるので、鋼中に含まれる元素を予め限定し、これらを極力減少させる必要がある。以下に、本発明の磁気シールド用素材に用いる鋼中に添加される元素、およびその添加量の限定理由について説明する。
【０００９】
Ｃに関しては、冷延鋼板中のＣ量が多いと炭化物が増加し、磁壁の移動を阻害され、また結晶粒の成長が妨げられ保磁力を低くすることが困難となるために、上限を０．０１０重量％以下とする。
Ｍｎに関しては、Ｂを含まない場合は０．２１重量％未満にする。０．２１重量％以上の場合は、磁気異方性が大きくなり有益だが、Ｂｒ／Ｈｃを劣化させるので好ましくない。
一方、Ｂを０．００１〜０．００３重量％含んだ場合、０．４０重量％以下にする。０．４０重量％を超えると、磁気異方性が大きくなり有益だが、Ｂｒ／Ｈｃを劣化させるので好ましくない。
Ｓｉに関しては、添加量が増加するほどＢｒ／Ｈｃが大きくなるが、めっきを施さない場合、黒化処理を行わねばならず、Ｓｉが黒化に悪影響を及ぼすため、添加量は０．０３０重量％とする。
Ｐに関しては、添加量が増加するほど、機械強度が増加し、好まれるが、過度に添加された場合、加工時に割れを起こす。したがって、本発明では、添加量は１．０重量％以下、望ましくは０．０３０重量％以下とする。
Ｓに関しては、熱間圧延時の割れにつながることから、添加量は０．０３０重量％以下、望ましくは、０．０１５重量％以下とする。
Ａｌに関しては、製鋼時の脱酸剤として使用、また、鋼中の固溶Ｎと反応し、窒化物（ＡｌＮ）となり、固溶Ｎを低減する。本発明では、Ｎが固溶し、結晶粒の微細化を防ぐこと、また、その固溶Ｎが、インナー加工時の耐ハンドリング強度アップにもつながる。
Ｂを含まない場合、結晶の微細化のためには、Ａｌ添加量は少ない方が良く、０．００５重量％以下とし、下限は不可逆的に混入される量とする。Ａｌ添加量が０．００５重量％を超えると、ＡｌＮが多量に析出し、結晶粒を微細化し、その結果、Ｂｒ／Ｈｃを小さくする。
一方Ｂを０．００１〜０．００３重量％含んだ場合、ＢがＮと親和力が強く、ＡｌＮの析出が抑制されるため、Ａｌ添加量は比較的多く含有しても良く、磁気特性に著しく悪影響を及ぼさず、０．０１０重量％以下とし、下限は０．００１重量％以上とする。Ａｌ添加量が０．０１０重量％を超えると、ＡｌＮが多量に析出し、結晶粒を微細化し、その結果、Ｂｒ／Ｈｃを小さくする。Ａｌ添加量が０．００１重量％未満では、脱酸の効果がほとんどなく好ましくない。
Ｎに関しては、本発明の磁気シールド用素材としてアルミキルド鋼を用いた場合に、Ｎは鋼中の固溶Ａｌと反応して微細なＡｌＮを形成し磁気特性を劣化させる。したがって、Ｎ添加量は、０．００７０重量％以下、望ましくは、０．００３０重量％以下とする。
Ｂに関しては、添加する場合、０．００１〜０．００３重量％の範囲が好ましい。０．００１重量％未満では、窒化物形成の効果あるいはストレッチャ−ストレインを抑制する効果が小さく、０．００３重量％を超えると、この効果が飽和するので経済的でない。
【００１０】
次に、磁気シールド用素材としての薄鋼板の製造工程について説明する。
まず、真空溶解、あるいは真空脱ガス法を用いて溶製された、上記の化学成分を含有するスラブを８８０〜９００℃程度のγ域の仕上げ温度で、熱間圧延し、５５０〜６５０℃で巻き取る。ただし、結晶粒をさらに大きくしたい場合は、８５０℃以下のα域圧延を行うことも可能で、ここでは熱延の条件は特に限定しない。
この極低炭素熱延鋼帯は酸洗で、熱間圧延工程で生じた酸化皮膜を除去した後に、次に、７０％以上の冷間圧延を施し、０．１０〜０．３０ｍｍの板厚とする。連続焼鈍は、磁気異方性を重要視する場合、鋼板に９Ｎ／ｍｍ２以上の架張を加えながら行った方が望ましい。その際の、焼鈍温度は必要とされる強度に応じて、Ｂを含まない場合は、６７０℃以上、Ｂを０．００１〜０．００３重量％含んだ場合は、７００℃以上の温度で２０秒以上の連続焼鈍を実施することが好ましい。これ以下では、再結晶が不十分のため、Ｂｒ／Ｈｃが６．０以上を得られない。上限の温度は、二次結晶による結晶粒の異常生長が起こらない範囲範囲内で有れば良く、約８３０℃である。時間もこの異常生長が起こらない範囲内であればよい。
また、一定の表面粗さＲａが必要な場合、または、Ｂｒ／Ｈｃより、磁気異方性の方を重視する場合には、焼鈍後に、調質圧延工程で伸び率５％以下の調質圧延を行い、一定の表面粗さＲａを付与することができる。表面粗さＲａ（ＪＩＳＢ ０６０１）として、０．１〜１．２μｍの範囲が良い。より好ましくは、０．２〜０．８μｍの範囲が良い。０．１μｍ未満では、黒化を行う場合、重ねて黒化焼鈍しても密着が生じやすい。また、１．２μｍより大きいと、黒化を行う際に、黒化ムラが生じやすくなるためである。
【００１１】
一般的には、シャドーマスクおよびインナーシールドはブラウン管内でのヘマタイト（Ｆｅ２Ｏ３）の発生を抑制、および、電子銃の輻射率を向上させるために、あらかじめ、ビスタイト（ＦｅＯ）、マグネタイト（Ｆｅ３Ｏ４）を多く生成させる黒化処理を施す。ここでは、この黒化処理を省略するため、上記の焼鈍を施した後、または、焼鈍後に調質圧延を行った後に、鋼板を電解脱脂、酸洗し、電解クロム酸処理（Ｃｒめっき）あるいはＮｉめっきを施す。電解クロム酸処理の場合、下層に金属クロム、上層にクロム水和酸化物からなる皮膜ができる。電解クロム酸処理層あるいはＮｉめっき層が表層に形成することで、ブラウン管内でのインナーシールドの酸化が抑制され、高真空度を保つことができる。このため、Ｃｒめっき量の範囲は、下層には金属クロム量がＣｒとして１０〜３００ｍｇ／ｍ２、上層にはクロム水和酸化物がＣｒとして１〜４０ｍｇ／ｍ２であることが好ましい。Ｎｉめっきの厚み範囲は、０．１〜３μｍが好ましい。また、Ｆｅ−Ｎｉ拡散層は、このＮｉめっき厚みの範囲を有する鋼板に熱処理により作製したもので良く、熱処理より表層にＮｉが残留しても良い。Ｆｅ−Ｎｉ拡散層を形成するための熱処理は、連続焼鈍前にＮｉめっきを行い、その後、これらの焼鈍により行っても良い。また、Ｎｉめっき後、再結晶しない温度範囲内で熱処理により、Ｆｅ−Ｎｉ拡散層を形成しても良い。
【００１２】
【実施例】
実施例にて本発明をさらに詳細に説明する。
（実施例）
表１に本発明の製造条件を示し、それぞれの機械特性、および、磁気特性を表２に示す。表には示さないが、実施例１〜３及び比較例１〜３と比較例７については、最表層に、Ｎｉめっきを約０．３μｍ施し、実施例６〜７及び比較例４については、最表層に下層に金属クロム約１００ｍｇ／ｍ２、上層にクロム水和酸化物をクロムとして約２０ｍｇ／ｍ２有する電解クロム酸処理を行った。実施例５については、冷間圧延後に、Ｎｉめっきを施し、その後の連続焼鈍でＦｅ−Ｎｉ拡散層を形成した。実施例４、実施例８については表層に表面処理を施さなかった。
【００１３】
【表１】
また、機械特性は、ＪＩＳ５号試験片を使って、引張試験にて、引張強度で評価した。磁気特性は、インナーシールド加工後に、４５０℃、１０分にて、焼鈍を施した後、エプスタイン法（１次捲線及び２次捲線を施し、外部磁場をかけて測定する方法、評価は７９６Ａ／ｍの磁界をかけた）にて、保磁力Ｈｃを評価した。
【００１５】
【表２】
磁気異方性については、圧延平行方向での残留磁束密度をＢｒ平行、圧延平行方向での保磁力をＨｃ平行、圧延直角方向での残留磁束密度をＢｒ直角、圧延直角方向での保磁力をＨｃ直角としてそれぞれ表した場合、（Ｂｒ平行／Ｈｃ平行）／（Ｂｒ直角／Ｈｃ直角）、または、この逆数のうち、いずれか大きな値で示した。この磁気異方性は１．３以上あることがより望ましい。表２では、機械特性は○は特性が優れていることを示す。磁気特性は、×は使用できず、○は磁気特性が良好であり、◎は磁気特性が特に優れていることを示す。総合評価において、×、△は実用上使用できない。○は実用上使用できる。
【００１７】
表２に示すように、本発明の磁気シールド用素材はＢｒ／Ｈｃは６．０（Ｔ・ｍ／Ａ）以上、望ましくは、１０．０以上ある。また、磁気異方性も１．３以上、望ましくは、１．５以上ある。そして、上記の磁気特性に加えて、機械特性もＴＳ２５０〜５００ＭＰａであり、カラー受像管用の磁気シールド用素材に適していることがわかる。また、調質圧延を施さない素材は特にＢｒ／Ｈｃが高く、優れており、調質圧延を５％以下の伸び率で行った場合は、特に磁気異方性に優れている。これに対し、比較例１〜９は十分な磁気シールド特性（Ｂｒ／Ｈｃ）が得られない。
【００１８】
【発明の効果】
本発明の磁気シールド用素材は、その優れた磁気特性と引張強度の点から、カラー受像管用の磁気シールド材として適用可能である。 また、本発明の磁気シールド用素材は、インナーシールド材とシャドウマスク材の間に介在して、両者をパネルに固着させるためのフレーム材としても適用可能である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetic shielding material for a color picture tube, and more particularly to a magnetic shielding material for a color picture tube having excellent internal magnetic shielding characteristics and excellent handling strength, and a method of manufacturing the same.
[0002]
[Prior art]
A color picture tube such as a color television basically consists of an electron gun and a phosphor screen that converts the electron beam into an image.In addition, the inside of the picture tube uses a magnetic field to reduce the movement of the electron beam by geomagnetism. It is covered with a shield material.
The steel sheet used as the material of this magnetic shield material has good magnetic formability, such as low geomagnetic drift, good formability such as bending, and the magnetic shield before or after processing. Mechanical properties such as handling strength that does not cause deformation when transporting materials or stacking workpieces are required.
[0003]
According to the conventional idea, it is necessary to minimize the amount of carbon and nitrogen in the steel, which hinder the movement of the magnetic domain wall, and increase the crystal grain size of a material that reduces the amount of geomagnetic drift. In the present invention, the amount of Al added is further reduced, the precipitation of AlN is reduced, and the crystal grains are coarsened. Alternatively, when a large amount of Al was added, the crystal grains were coarsened by adding B, which has a higher affinity for N than Al. This is because BN has a larger precipitate size than AlN, but has a smaller number of precipitates, and thus utilizes the effect of suppressing the grain refinement of AlN.
Further, depending on the use of the user, anisotropy of magnetism with respect to the rolling direction of the steel sheet may be desired. In this case, the tension during annealing is increased and temper rolling is performed. The definition of desired characteristics and the range thereof are described above. It is desired that the steel sheet has a property of being easily magnetized, and as a parameter, a ratio of a residual magnetic flux density (hereinafter, represented by Br, unit: T) to a coercive force (hereinafter, represented by Hc, unit: A / m): Br / Hc (unit: T · m / A) is preferably 6.0 or more, more preferably 10.0 or more.
Further, when the inner shield is used together with an extension tension type shadow mask, it is more desirable that the magnetic anisotropy is large in the direction perpendicular to the rolling direction of the steel sheet. Anisotropy = (residual magnetic flux density in the rolling parallel direction (Br parallel) / coercive force (Hc parallel)) / (residual magnetic flux density in the rolling perpendicular direction (Br perpendicular) / coercive force (Hc perpendicular)), or This reciprocal is defined as any larger value, and the magnetic anisotropy is more preferably 1.3 or more, preferably 1.5 or more. From the viewpoint of workability and handling strength, when carbon and nitrogen in the steel are reduced and the crystal grain size is increased, the strength of the steel sheet is reduced, and the formability such as bending is improved. When the bent workpiece is transported, unevenness is caused by a slight impact, or the workpiece is easily deformed by weight when the workpieces are stacked. It is necessary to simultaneously satisfy the above-mentioned contradictory excellent magnetic properties and excellent handling strength, and from that point, the mechanical strength (tensile strength: hereinafter, referred to as TS) is 250 to 500 MPa.
[0004]
Conventionally, as a material having a magnetic shielding property, there is a soft magnetic silicon steel sheet or an ultra-low carbon steel sheet having excellent handling strength, and the former has a blackening treatment required for a color picture tube. There is no example used to be difficult. The latter has coarse crystal grains and is excellent in magnetic shielding properties, but has not been obtained having sufficient handling strength.
[0005]
[Problems to be solved by the invention]
The present invention has excellent magnetic properties with Br / Hc of 6.0 or more, preferably 10.0 or more, and magnetic anisotropy of 1.3 or more. Which of these magnetic properties is superior depends on the user of the CRT. It is another object of the present invention to provide a magnetic shielding material for a color picture tube having an excellent handling strength of TS = 250 to 500 MPa.
[0006]
[Means to solve the problem]
The magnetic shielding material for a color picture tube according to claim 1, wherein C: 0.010% by weight or less, Si: 0.03% by weight or less, Mn: less than 0.21% by weight, P: 1.0% by weight or less, S: 0.030% by weight or less, Al: 0.005% by weight or less, N: 0.007% by weight or less, with the balance being Fe and a steel sheet of unavoidable impurities.
The magnetic shielding material for a color picture tube according to claim 2, wherein C: 0.010% by weight or less, Si: 0.03% by weight or less, Mn: 0.40% by weight or less, P: 1.0% by weight or less, S: 0.030% by weight or less, Al: 0.010% by weight or less, N: 0.007% by weight or less, B: 0.001 to 0.003% by weight, the balance being Fe and unavoidable impurities Characterized by the following.
The magnetic shielding material for a color picture tube according to claim 3, wherein C: 0.010% by weight or less, Si: 0.03% by weight or less, Mn: less than 0.21% by weight, P: 1.0% by weight or less, S: 0.030% by weight or less, Al: 0.005% by weight or less, N: 0.007% by weight or less, the balance being Fe and unavoidable impurities on the surface of the steel plate, a Cr plating layer, a Ni plating layer or It has a Fe-Ni diffusion layer. The magnetic shielding material for a color picture tube according to claim 4, wherein C: 0.010% by weight or less, Si: 0.03% by weight or less, Mn: 0.40% by weight or less, P: 1.0% by weight or less, S: 0.030% by weight or less, Al: 0.010% by weight or less, N: 0.007% by weight or less, B: 0.001 to 0.003% by weight, the balance being Fe and unavoidable impurities Is characterized by having a Cr plating layer, a Ni plating layer, or an Fe-Ni diffusion layer on the surface of.
The method for producing a magnetic shielding material for a color picture tube according to claim 5, wherein: C: 0.010% by weight or less, Si: 0.03% by weight or less, Mn: less than 0.21% by weight, P: 1.0 Cold rolling is performed on a steel sheet containing not more than 0.3% by weight, S: not more than 0.030% by weight, Al: not more than 0.005% by weight, and N: not more than 0.007% by weight, with the balance being Fe and unavoidable impurities. After continuous annealing at a temperature of 670 ° C. or higher, Cr plating or Ni plating is performed.
The method for producing a magnetic shielding material for a color picture tube according to claim 6, wherein: C: 0.010% by weight or less, Si: 0.03% by weight or less, Mn: 0.40% by weight or less, P: 1.0 % By weight, S: 0.030% by weight or less, Al: 0.010% by weight or less, N: 0.007% by weight or less, B: 0.001 to 0.003% by weight, the balance being Fe and inevitable It is characterized by subjecting a steel sheet of a target impurity to cold rolling, performing continuous annealing at a temperature of 700 ° C. or more, and then performing Cr plating or Ni plating. The method for producing a magnetic shielding material for a color picture tube according to claim 7, wherein C: 0.010% by weight or less, Si: 0.03% by weight or less, Mn: less than 0.21% by weight, P: 1. 0% by weight or less, S: 0.030% by weight or less, Al: 0.005% by weight or less, N: 0.007% by weight or less, the balance being Fe and unavoidable impurities. It is characterized by performing continuous annealing at a temperature of 670 ° C. or more, performing temper rolling at an elongation of 5% or less, and then performing Cr plating or Ni plating.
The method for producing a magnetic shielding material for a color picture tube according to claim 8, wherein C: 0.010% by weight or less, Si: 0.03% by weight or less, Mn: 0.40% by weight or less, P: 1.0 % By weight, S: 0.030% by weight or less, Al: 0.010% by weight or less, N: 0.007% by weight or less, B: 0.001 to 0.003% by weight, the balance being Fe and inevitable It is characterized by subjecting a steel sheet of a target impurity to cold rolling, performing continuous annealing at a temperature of 700 ° C. or more, performing temper rolling at an elongation of 5% or less, and then performing Cr plating or Ni plating.
A magnetic shielding material for a color picture tube according to a ninth aspect is a magnetic shielding material for a color picture tube manufactured using the magnetic shielding material for a color picture tube according to any one of the first to fourth aspects.
A magnetic shield material for a color picture tube according to a tenth aspect is a magnetic shield material for a color picture tube manufactured by using the method for manufacturing a magnetic shield material for a color picture tube according to any one of the fifth to eighth aspects.
A color picture tube according to an eleventh aspect is a color picture tube manufactured using the magnetic shielding material for a color picture tube according to any one of the ninth to tenth aspects.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, the ultra-low carbon steel is cold-rolled and continuously annealed at a temperature of 670 ° C. or more in the case of the component system of claim 1 and 700 ° C. or more in the case of the component system of claim 2, and if necessary. Subjected to temper rolling, has a Br / Hc of at least 6.0, preferably at least 10.0, and a magnetic anisotropy of at least 1.3, preferably at least 1.5. Characteristics. S. : It was found that a material for a magnetic shield for a color picture tube having an excellent handling strength of 250 to 500 MPa was obtained.
[0008]
Hereinafter, the present invention will be described in detail with reference to examples.
The ultra-low carbon steel used for the magnetic shielding material for the color picture tube of the present invention is decarburized using a vacuum degassing method, denitrified, and subjected to hot rolling and continuous annealing to obtain a grain size ASTM. No. Annealing is performed at 670 ° C. or more for the steel component of claim 1 and 700 ° C. or more for the steel component of claim 2 so that the steel component is 5.0 to 7.5. In order to impart excellent magnetic anisotropy to the steel sheet, it is preferable that the steel sheet is stretched with a tension of 9 N / mm 2 or more during continuous annealing.
Further, excessive carbides and nitrides finely dispersed in steel hinder domain wall movement and deteriorate magnetic properties. Therefore, it is necessary to limit the elements contained in steel in advance and reduce them as much as possible. Hereinafter, the elements added to the steel used for the magnetic shielding material of the present invention and the reasons for limiting the amounts of the elements will be described.
[0009]
Regarding C, if the amount of C in the cold-rolled steel sheet is large, carbides increase, the movement of domain walls is hindered, and the growth of crystal grains is hindered, making it difficult to lower the coercive force. 0.010% by weight or less.
Regarding Mn, when B is not contained, the content is set to less than 0.21% by weight. When the content is 0.21% by weight or more, the magnetic anisotropy increases, which is beneficial, but undesirably deteriorates Br / Hc.
On the other hand, when B is contained in an amount of 0.001 to 0.003% by weight, the content is set to 0.40% by weight or less. If it exceeds 0.40% by weight, the magnetic anisotropy increases, which is beneficial, but it is not preferable because Br / Hc is deteriorated.
Regarding Si, the Br / Hc increases as the addition amount increases. However, when plating is not performed, blackening treatment must be performed, and Si has an adverse effect on blackening. %.
Regarding P, as the addition amount increases, the mechanical strength increases, which is preferable. However, if added excessively, cracks occur during processing. Therefore, in the present invention, the addition amount is 1.0% by weight or less, preferably 0.030% by weight or less.
S is added in an amount of 0.030% by weight or less, desirably 0.015% by weight or less because it causes cracking during hot rolling.
Al is used as a deoxidizing agent in steel making, and reacts with solute N in steel to form nitride (AlN), thereby reducing solute N. In the present invention, N forms a solid solution to prevent crystal grains from being refined, and the solid solution N leads to an increase in handling resistance during inner processing.
When B is not contained, the smaller the amount of Al added, the better the amount of Al added is 0.005% by weight or less, and the lower limit is the amount irreversibly mixed in order to refine the crystal. If the added amount of Al exceeds 0.005% by weight, a large amount of AlN precipitates and the crystal grains are refined, and as a result, Br / Hc is reduced.
On the other hand, if B is contained in an amount of 0.001 to 0.003% by weight, B has a strong affinity for N and suppresses the precipitation of AlN. Without adverse effect, the content is set to 0.010% by weight or less, and the lower limit is set to 0.001% by weight or more. If the added amount of Al exceeds 0.010% by weight, a large amount of AlN precipitates and the crystal grains are refined, and as a result, Br / Hc is reduced. If the amount of Al added is less than 0.001% by weight, the effect of deoxidation hardly occurs, which is not preferable.
Regarding N, when aluminum-killed steel is used as the magnetic shielding material of the present invention, N reacts with solute Al in the steel to form fine AlN and deteriorate magnetic properties. Therefore, the amount of N added is set to 0.0070% by weight or less, preferably 0.0030% by weight or less.
When B is added, the content is preferably in the range of 0.001 to 0.003% by weight. If the amount is less than 0.001% by weight, the effect of forming nitrides or the effect of suppressing stretcher strain is small. If the amount exceeds 0.003% by weight, this effect is saturated, so that it is not economical.
[0010]
Next, a manufacturing process of a thin steel sheet as a material for a magnetic shield will be described.
First, a slab containing the above-mentioned chemical components, produced by vacuum melting or vacuum degassing, is hot-rolled at a finishing temperature of about 880 to 900 ° C. in a γ region, and heated at 550 to 650 ° C. Take up. However, if it is desired to further increase the crystal grains, it is possible to perform α-region rolling at 850 ° C. or lower, and the conditions for hot rolling are not particularly limited here.
This ultra-low carbon hot rolled steel strip is pickled to remove an oxide film generated in a hot rolling step, and then subjected to cold rolling of 70% or more to obtain a sheet thickness of 0.10 to 0.30 mm. And When importance is placed on magnetic anisotropy, continuous annealing is desirably performed while applying a stretch of 9 N / mm 2 or more to the steel sheet. The annealing temperature at that time depends on the required strength. If B is not contained, the annealing temperature is 670 ° C. or more, and if B is contained at 0.001 to 0.003% by weight, the temperature is 20 ° C. or more. It is preferable to carry out continuous annealing for at least two seconds. Below this, Br / Hc of 6.0 or more cannot be obtained due to insufficient recrystallization. The upper limit temperature may be within a range where abnormal growth of crystal grains due to the secondary crystal does not occur, and is about 830 ° C. The time may be within the range where the abnormal growth does not occur.
When a constant surface roughness Ra is required, or when magnetic anisotropy is more important than Br / Hc, the temper rolling at an elongation of 5% or less in the temper rolling step after annealing. Is performed to give a constant surface roughness Ra. The surface roughness Ra (JISB 0601) is preferably in the range of 0.1 to 1.2 μm. More preferably, the range is 0.2 to 0.8 μm. When the thickness is less than 0.1 μm, in the case of performing blackening, adhesion tends to occur even when the blackening annealing is performed repeatedly. On the other hand, if it is larger than 1.2 μm, blackening unevenness is likely to occur when blackening is performed.
[0011]
Generally, in order to suppress the generation of hematite (Fe 2 O 3 ) in a cathode ray tube and to improve the emissivity of an electron gun, a shadow mask and an inner shield are used in advance to prevent the occurrence of bistitite (FeO), magnetite (Fe). A blackening process for generating a large amount of 3 O 4 ) is performed. Here, in order to omit this blackening treatment, the steel sheet is subjected to electrolytic degreasing, pickling, and electrolytic chromic acid treatment (Cr plating) after the above-described annealing or after temper rolling after annealing. Ni plating is applied. In the case of electrolytic chromic acid treatment, a film composed of chromium metal is formed in the lower layer and a chromium hydrate oxide is formed in the upper layer. By forming the electrolytic chromic acid treatment layer or the Ni plating layer on the surface layer, oxidation of the inner shield in the cathode ray tube is suppressed, and a high degree of vacuum can be maintained. For this reason, the range of the amount of Cr plating is preferably such that the lower layer has a chromium metal content of 10 to 300 mg / m 2 as Cr and the upper layer has a chromium hydrated oxide of 1 to 40 mg / m 2 as Cr. The thickness range of the Ni plating is preferably 0.1 to 3 μm. The Fe—Ni diffusion layer may be formed by heat treatment on a steel sheet having the Ni plating thickness range, and Ni may remain on the surface layer by the heat treatment. The heat treatment for forming the Fe—Ni diffusion layer may be performed by performing Ni plating before continuous annealing and thereafter performing the annealing. After the Ni plating, the Fe—Ni diffusion layer may be formed by heat treatment within a temperature range that does not cause recrystallization.
[0012]
【Example】
The present invention will be described in more detail with reference to examples.
(Example)
Table 1 shows the manufacturing conditions of the present invention, and Table 2 shows the mechanical properties and magnetic properties of each. Although not shown in the table, for Examples 1 to 3 and Comparative Examples 1 to 3 and Comparative Example 7, about 0.3 μm of Ni plating was applied to the outermost layer, and for Examples 6 to 7 and Comparative Example 4, The outermost layer was subjected to electrolytic chromic acid treatment in which the lower layer had about 100 mg / m 2 of chromium metal and the upper layer had about 20 mg / m 2 of chromium hydrated oxide as chromium. In Example 5, after cold rolling, Ni plating was performed, and a Fe—Ni diffusion layer was formed by subsequent continuous annealing. In Examples 4 and 8, the surface treatment was not performed on the surface layer.
[0013]
[Table 1]
The mechanical properties were evaluated by tensile strength in a tensile test using a JIS No. 5 test piece. After the inner shield processing, the magnetic properties were annealed at 450 ° C. for 10 minutes, and then subjected to the Epstein method (a method of applying a primary winding and a secondary winding and applying an external magnetic field, and the evaluation was 796 A / m). Was applied to evaluate the coercive force Hc.
[0015]
[Table 2]
Regarding the magnetic anisotropy, the residual magnetic flux density in the direction parallel to the rolling direction is Br parallel, the coercive force in the direction parallel to the rolling direction is Hc parallel, the residual magnetic flux density in the direction perpendicular to the rolling direction is Br perpendicular, and the coercive force in the direction perpendicular to the rolling direction. When expressed as Hc right angles, they are represented by (Br parallel / Hc parallel) / (Br right angle / Hc right angle) or their reciprocal, whichever is larger. This magnetic anisotropy is more desirably 1.3 or more. In Table 2, “機械” indicates that the mechanical properties are excellent. Regarding the magnetic properties, x indicates that the magnetic properties cannot be used, ○ indicates that the magnetic properties are good, and ◎ indicates that the magnetic properties are particularly excellent. In the comprehensive evaluation, × and Δ cannot be used practically. ○ can be used practically.
[0017]
As shown in Table 2, the magnetic shielding material of the present invention has Br / Hc of 6.0 (Tm / A) or more, preferably 10.0 or more. The magnetic anisotropy is 1.3 or more, preferably 1.5 or more. Further, in addition to the above magnetic characteristics, the mechanical characteristics are also TS 250 to 500 MPa, which indicates that the material is suitable for a magnetic shielding material for a color picture tube. A material that is not subjected to temper rolling is particularly excellent in high Br / Hc, and is particularly excellent in magnetic anisotropy when temper rolling is performed at an elongation of 5% or less. On the other hand, in Comparative Examples 1 to 9, sufficient magnetic shield characteristics (Br / Hc) cannot be obtained.
[0018]
【The invention's effect】
The magnetic shielding material of the present invention can be applied as a magnetic shielding material for a color picture tube because of its excellent magnetic properties and tensile strength. Further, the material for magnetic shield of the present invention can be applied as a frame material for interposing between the inner shield material and the shadow mask material and fixing both to the panel.
Claims (11)
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| JP2007277699A (en) * | 2006-03-14 | 2007-10-25 | Jfe Steel Kk | Steel sheet and its production method |
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| JP2007277699A (en) * | 2006-03-14 | 2007-10-25 | Jfe Steel Kk | Steel sheet and its production method |
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