JP3527374B2 - Heat-resistant painted Zn-55% Al alloy plated steel sheet with excellent press workability - Google Patents
Heat-resistant painted Zn-55% Al alloy plated steel sheet with excellent press workabilityInfo
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- JP3527374B2 JP3527374B2 JP30012696A JP30012696A JP3527374B2 JP 3527374 B2 JP3527374 B2 JP 3527374B2 JP 30012696 A JP30012696 A JP 30012696A JP 30012696 A JP30012696 A JP 30012696A JP 3527374 B2 JP3527374 B2 JP 3527374B2
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- steel sheet
- heat
- plating layer
- alloy
- plated steel
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Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、プレス加工性に優れた
耐熱塗装Ｚｎ−５５％Ａｌ合金めっき鋼板に関する。
【０００２】
【従来の技術】Ｚｎ−Ａｌ系合金めっきは、耐食性，耐
候性，耐熱性に優れている。この特徴を活用し、暖房機
器，炊飯器，ガス器具，建築外装用鋼板，家電製品用外
板等の広範な分野で、プレス加工品にして使用されてい
る。なかでも、Ｚｎ−５５％Ａｌ合金めっき鋼板は、従
来の溶融Ｚｎめっき鋼板に比較して耐熱性にも優れてい
る。そこで、Ｚｎ−５５％Ａｌ合金めっき鋼板に耐熱塗
料をプレコートしたものが、耐熱性を要求される部品と
して各種の形状に成形加工され、高価なＳＵＳ３０４
系，ＳＵＳ４３０系等のステンレス鋼板の代替品として
提供されている。たとえば、Ｚｎ−５５％Ａｌ合金めっ
き鋼板に耐熱性非粘着性塗料をプレコートした鋼板は、
ガステーブルの天板，電子レンジオーブンの内箱等に成
形加工されており、最近ではＺｎ−５５％Ａｌ合金めっ
き鋼板がもつ耐熱性，耐熱反射性等を活用し、更に低コ
スト化を図るため片面のみに耐熱塗料をプレコートした
鋼板が使用されるようになってきている。
【０００３】
【発明が解決しようとする課題】耐熱塗料をプレコート
したＺｎ−５５％Ａｌ合金めっき鋼板は、塗装皮膜その
ものが潤滑性に優れていることから、プレス製造におい
て脱脂工程の省略によるコストダウンを狙ってプレス油
なしで加工することが多くなってきている。また、片面
に耐熱塗料をプレコートしたものも、脱脂が不要な揮発
性のプレス油を塗装鋼板の表面にスプレー等で施した
後、プレス加工し、加工品に付着しているプレス油を自
然に揮発させることによりコストダウンが図られてい
る。ところが、たとえば耐熱塗料を両面にプレコートし
たＺｎ−５５％Ａｌ合金めっき鋼板をオーステナイト系
のＳＵＳ３０４系ステンレス鋼板の代替材として使用す
るような場合、皮膜そのものは潤滑性に優れているもの
の母材が普通鋼であり、ＳＵＳ３０４系のステンレス鋼
に比べて加工硬化指数が小さく張出し加工性に劣る。そ
のため、ＳＵＳ３０４系のステンレス鋼板と同一形状の
製品に加工すると、割れが発生し加工品が得られないこ
とがある。そのため、代替材として使用するには、製品
形状の変更が余儀なくされている。
【０００４】また、耐熱塗料を片面のみにプレコートし
たＺｎ−５５％Ａｌ合金めっき鋼板は、低粘度の揮発性
プレス油を使用してプレス加工すると、金型へのめっき
層の凝着を防止することが困難であり、金型に凝着した
めっき層を除去する作業が必要となり、生産性の低下を
引き起こしている。また、ロット間でプレス加工性の変
動が大きく、数枚のプレス加工で鋼板が破断するものが
あり、プレス加工が安定しないといった問題もある。本
発明は、このような問題を解消すべく案出されたもので
あり、めっき層の物性を調整することにより、プレス加
工性に優れた耐熱塗装Ｚｎ−５５％Ａｌ合金めっき鋼板
を提供することを目的とする。
【０００５】
【課題を解決するための手段】本発明の耐熱塗装Ｚｎ−
５５％Ａｌ合金めっき鋼板は、その目的を達成するた
め、結晶粒径１ｍｍ以下，表面粗さＲa ０．１〜１μｍ
及び硬さ１００以上に調整したＺｎ−５５％Ａｌ合金め
っき層の上に耐熱塗装が施されていることを特徴とす
る。塗装原板のめっき層は、めっき直後の急冷処理によ
って１ｍｍ以下の結晶粒径に調整される。急冷には、
水，水−空気混合物，塩化物を含む水溶液等を噴霧する
方法や冷気吹付け法が採用される。めっき層のビッカー
ス硬さも、この急冷処理によって１００以上に調整され
る。めっき層の表面粗さは、めっき層の結晶粒径を１ｍ
ｍ以下にさせる冷却処理の冷媒の噴出圧力の制御，めっ
き後の調質圧延時の圧延ロールの表面粗さの調整，冷媒
の噴出圧力の制御と調質圧延の圧延ロールの調整との併
用によって、Ｒa ０．１〜１μｍ範囲に調整できる。
【０００６】
【作用】耐熱塗装Ｚｎ−５５％Ａｌ合金めっき鋼板は、
めっき層に靭性がなく延性が乏しい。そのため、プレス
加工の際に歪みが加わると鋼板の変形にめっき層が追従
できず、めっき層に亀裂が発生し易い。この亀裂は、め
っき層の結晶粒界に沿って発生し、結晶粒内にほとんど
発生しないことから、結晶粒界に生じた亀裂の直下にあ
る鋼板にのみ応力が集中し易い。その結果、歪みの増加
に従ってめっき層の亀裂直下にある鋼板への応力集中が
局部的に大きくなり、応力集中部を起点にして鋼板が破
断に至ることがある。本発明の耐熱塗装Ｚｎ−５５％Ａ
ｌ合金めっき鋼板は、めっき層の亀裂に起因する鋼板へ
の応力集中をめっき層の結晶粒径、換言すればスパング
ルを小さくすることにより緩和している。すなわち、め
っき層の結晶粒径を１ｍｍ未満の微小粒に調整してプレ
ス加工時の歪みでめっき層に発生する亀裂を緻密化させ
ると、亀裂直下の鋼板に生じる応力集中の部位が高密度
で且つ数多く生成される。そのため、亀裂直下にある鋼
板への応力集中が分散され、加工割れが発生し難くな
り、プレス加工性が改善される。
【０００７】これに対し、めっき層の結晶粒が粒径１ｍ
ｍを超える粗粒になると、プレス加工時の歪みにより生
じるめっき層の亀裂が結晶粒径の粗大化と共に低密度で
且つ少数になる。すなわち、めっき層の亀裂直下にある
鋼板に応力が局部的に集中し、鋼板の加工性が著しく損
なわれ、加工性が大きく低下する。Ｚｎ−５５％Ａｌ合
金めっき層のプレス加工における型かじりは、めっき層
と金型とが直接に接触して摺動することにより発生す
る。したがって、めっき層が持つ耐熱性，熱反射性等を
活用し或いは低コスト化を狙って耐熱塗料を片面のみに
プレコートしたＺｎ−５５％Ａｌ合金めっき鋼板の場合
には、プレス加工の際に、めっき層と金型との接触防止
に十分な量のプレス油をめっき層表面の凹部に保持でき
るようにするためには、めっき層の表面粗さをＲa ０．
１〜１μｍ範囲に調整することが好ましい。めっき層の
表面粗さがこの範囲にあれば、めっき層表面の凹部に保
持されたプレス油がプレス加工時に滲み出し、めっき層
と金型との直接接触が防止される。
【０００８】めっき層の表面粗さがＲa ０．１μｍに満
たないと、めっき層表面の凹部に十分な量のプレス油が
保持されず、プレス加工時にめっき層表面凹部に保持さ
れたプレス油の滲出しがあってもめっき層と金型とが接
触して摺動することになる。その結果、めっき層が金型
に焼き付き、かじりが発生する。逆にＲa １μｍを超え
る表面粗さでは、高面圧によってめっき層表面の凸部が
金型に接触し、押し潰された部位への滲出しが不十分と
なり、型かじりが発生し易くなる。耐熱塗料を片面のみ
にプレコートしたＺｎ−５５％Ａｌ合金めっき鋼板で
は、めっき層のビッカース硬さを１００以上にすると、
プレス加工時にめっき層の一部が金型に接触状態で摺動
しても、硬質化しためっき層のため型かじりが防止され
る、ビッカース硬さが１００を下回るめっき層では、プ
レス加工時にめっき面の一部が金型に接触摺動すると型
かじりが発生する虞れがある。
【０００９】
【実施例】
実施例１：Ｚｎ４５重量％及びＡｌ５５重量％の組成を
もつ溶融めっき浴中に、板厚０．６ｍｍの深絞り用冷延
鋼帯を連続通板し、溶融めっきを施した。めっき付着量
は、めっき浴から引き上げられた直後の鋼板をガスワイ
ピングすることにより９０ｇ／ｍ2 （めっき厚：１２μ
ｍ）に調整した。めっき直後の冷却工程では、比較例で
は放冷しながらリコイラに巻き取った。他方、本発明例
では、めっき直後の冷却工程で水又は塩化物水溶液を用
いた液体噴霧でめっき層を急冷し、結晶粒径１ｍｍ以
下，表面粗さＲa ０．１〜１μｍ，ビッカース硬さ１０
０以上となるようにめっき層を調整した。形成された各
Ｚｎ−５５％Ａｌ合金めっき層の物性を表１に示す。
【００１０】
【００１１】表１に示した各めっき層が形成されたＺｎ
−５５％Ａｌ合金めっき鋼帯を塗装原板とし、連続塗装
ラインで脱脂処理後の鋼帯に乾燥膜厚が１５μｍ（片
面）となるようにフッ素系耐熱非粘着性塗料を両面に塗
布し、加熱温度４００℃で焼成した。耐熱塗装を施した
Ｚｎ−５５％Ａｌ合金めっき鋼板について、張出し加工
性を調査した。試験には、ロックビード付きのダイ及び
ブランクホルダーを使用し、ブランク径２５０ｍｍ，パ
ンチ径２００ｍｍ，パンチ肩半径１０ｍｍ，ダイ肩半径
３ｍｍ，しわ押え力２５０ＫＮ，プレス油なしの条件下
で純粋張出し加工し、亀裂，破断等の発生しない張出し
高さを求めた。
【００１２】表２の調査結果にみられるように、本発明
にしたがった両面耐熱塗装Ｚｎ−５５％Ａｌ合金めっき
鋼板は、何れも４５ｍｍ以上の加工高さが得られてお
り、極めて優れた張出し加工性を示した。これに対し、
比較例である両面耐熱塗装Ｚｎ−５５％Ａｌ合金めっき
鋼板は、何れも２２ｍｍ以下の加工高さとなっており、
張出し加工性が劣っていた。これは、プレス加工時の歪
みにより生じるめっき層の亀裂が結晶粒の粗大化によっ
て低密度で且つ少数となり、めっき層の亀裂の直下にあ
る鋼板に応力が局部的に集中した結果であると推察され
る。
【００１３】
【００１４】実施例２：表１と同じＺｎ−５５％Ａｌ合
金めっき鋼帯を塗装原板として使用し、連続塗装ライン
で脱脂処理された鋼帯の片面に乾燥膜厚が１５μｍとな
るようにフッ素系耐熱非粘着性塗料を塗布し、加熱温度
４００℃で焼成した。本発明例及び比較例の片面に耐熱
塗装したＺｎ−５５％Ａｌ合金めっき鋼板について、低
粘度の揮発性プレス油Ｓ−１００Ｊ（杉村化学工業株式
会社製）を用い、めっき面をダイ側にして絞り加工性及
び耐かじり性を調査した。試験には３８０ｍｍ径のブラ
ンクを使用し、パンチ径２００ｍｍ，パンチ肩半径１０
ｍｍ，ダイ肩半径５ｍｍ，絞り高さ１００ｍｍの条件下
で板押え力を変化させて円筒絞り加工し、しわ及び割れ
が発生しない板押え力の範囲、いわゆる成形可能な板押
え力の範囲を求めると共に、型かじりの状態を観察し
た。
【００１５】表３の調査結果にみられるように、本発明
に従ったＺｎ−５５％Ａｌ合金めっき層に耐熱塗料を片
面に塗装した鋼板は、成形可能な板押え力の範囲が１０
０〜２８０ｋＮと広く、極めて優れた絞り加工性及び耐
かじり性を示した。これに対し、比較例であるめっき層
を放冷した片面耐熱塗装Ｚｎ−５５％Ａｌ合金めっき鋼
板は、成形可能な板押え力の範囲が１００〜１５０ｋＮ
と狭く、絞り加工性及び耐かじり性が劣っていた。これ
は、プレス加工時の歪みにより生じるめっき層の亀裂が
結晶粒の粗大化によって低密度で且つ少数となり、めっ
き層の亀裂の直下にある鋼板へ応力が局部的に集中して
鋼板が破断し易くなることと、金型にめっき層が焼き付
き、摩擦抵抗を著しく上昇させることが相俟った結果で
あると推察される。
【００１６】
【００１７】
【発明の効果】以上に説明したように、本発明の耐熱塗
装Ｚｎ−５５％Ａｌ合金めっき鋼板は、めっき層の結晶
粒径を１ｍｍ以下に調整することにより、プレス加工時
に発生する応力が集中する箇所を分散させ、局部的な応
力集中に起因した加工割れが発生し難くなる。そのた
め、従来の耐熱塗装を施したＺｎ−５５％Ａｌ合金めっ
き鋼板に比較して、絞り加工性及び張出し加工性が２倍
以上も優れた耐熱塗装Ｚｎ−５５％Ａｌ合金めっき鋼板
が得られる。また、結晶粒径を１ｍｍ以下に規制するこ
とに併せて、表面粗さＲa ０．１〜１μｍ，ビッカース
硬さ１００以上にめっき層を調整することにより、耐か
じり性が著しく改善され、摩擦抵抗を小さくすることが
できる。このため、プレス加工時に揮発性の低粘度プレ
ス油を使用しても、めっき層の金型への凝着が抑制され
るようになり、金型のメンテナンス頻度の少ない連続プ
レス加工性に優れた片面耐熱塗装Ｚｎ−５５％Ａｌ合金
めっき鋼板が得られる。しかも、めっき層がＺｎ−５５
％Ａｌ合金であり、一般のＺｎめっき鋼板に比較して耐
熱性及び耐久性に優れていることから、その特性を活用
し、過酷な加工が施されるガステーブルの天板，電子レ
ンジオーブンの内箱，家電製品，厨房製品等として広範
な分野で使用される。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant coated Zn-55% Al alloy coated steel sheet having excellent press workability. [0002] Zn-Al based alloy plating is excellent in corrosion resistance, weather resistance and heat resistance. Utilizing this feature, it is used as a press-processed product in a wide range of fields such as heating equipment, rice cookers, gas appliances, steel plates for building exterior, and outer panels for home appliances. Above all, the Zn-55% Al alloy-plated steel sheet has excellent heat resistance as compared with the conventional hot-dip Zn-coated steel sheet. Therefore, a material obtained by pre-coating a heat-resistant paint on a Zn-55% Al alloy-plated steel sheet is formed into various shapes as a part requiring heat resistance, and is expensive SUS304.
Series, SUS430 series, etc. are offered as substitutes for stainless steel plates. For example, a steel sheet in which a heat-resistant and non-adhesive paint is pre-coated on a Zn-55% Al alloy-plated steel sheet,
Formed on the top plate of a gas table, the inner box of a microwave oven, etc. In order to further reduce costs by utilizing the heat resistance and heat reflection properties of the Zn-55% Al alloy plated steel sheet recently. Steel sheets pre-coated with heat-resistant paint on only one side have been used. [0003] In a Zn-55% Al alloy-plated steel sheet precoated with a heat-resistant paint, the coating film itself is excellent in lubricity, so that the cost can be reduced by omitting the degreasing step in press production. It is becoming more common to work without press oil for the purpose. In addition, even if the heat-resistant paint is pre-coated on one side, a volatile press oil that does not require degreasing is applied to the surface of the coated steel plate by spraying, etc., and then pressed to naturally remove the press oil adhering to the processed product. The cost is reduced by volatilization. However, for example, when a Zn-55% Al alloy plated steel sheet precoated on both sides with a heat-resistant paint is used as a substitute for an austenitic SUS304 stainless steel sheet, the film itself is excellent in lubricity but the base material is usually used. It is a steel and has a smaller work hardening index than SUS304 stainless steel and is inferior in stretchability. Therefore, when processed into a product having the same shape as the SUS304 stainless steel plate, cracks may occur and a processed product may not be obtained. Therefore, in order to use it as a substitute, the shape of the product must be changed. Further, when a Zn-55% Al alloy-plated steel sheet having a heat-resistant paint precoated only on one side is pressed using a low-viscosity volatile press oil, adhesion of a plating layer to a mold is prevented. Therefore, it is necessary to remove the plating layer adhered to the mold, which causes a decrease in productivity. In addition, there is a problem that the press workability varies greatly between lots, and there is a case in which a steel sheet is broken by several press work, and the press work is not stable. The present invention has been devised to solve such a problem, and provides a heat-resistant painted Zn-55% Al alloy-plated steel sheet excellent in press workability by adjusting physical properties of a plating layer. With the goal. [0005] The heat-resistant coating Zn- of the present invention.
In order to achieve the object, a 55% Al alloy plated steel sheet has a crystal grain size of 1 mm or less and a surface roughness Ra of 0.1 to 1 μm.
A heat-resistant coating is applied on the Zn-55% Al alloy plating layer adjusted to have a hardness of 100 or more. The plating layer of the coating original plate is adjusted to a crystal grain size of 1 mm or less by a quenching treatment immediately after plating. For quenching,
A method of spraying water, a water-air mixture, an aqueous solution containing chloride, and the like, and a method of spraying cold air are employed. The Vickers hardness of the plating layer is also adjusted to 100 or more by this quenching treatment. The surface roughness of the plating layer is determined by measuring the crystal grain size of the plating layer by 1 m.
m by controlling the pressure of the refrigerant to be cooled during the cooling process, adjusting the surface roughness of the rolls during temper rolling after plating, and controlling the pressure of the refrigerant and adjusting the rolls of the temper rolling. , it can be adjusted to R a 0.1 to 1 [mu] m range. The heat-resistant coated Zn-55% Al alloy plated steel sheet is
The plating layer has no toughness and poor ductility. Therefore, if strain is applied during the press working, the plating layer cannot follow the deformation of the steel sheet, and cracks are likely to occur in the plating layer. Since this crack occurs along the crystal grain boundary of the plating layer and hardly occurs in the crystal grain, the stress tends to concentrate only on the steel sheet immediately below the crack generated in the crystal grain boundary. As a result, as the strain increases, the concentration of stress on the steel sheet immediately below the crack in the plating layer locally increases, and the steel sheet may be broken starting from the stress concentration part. Heat-resistant coating of the present invention Zn-55% A
In the 1-alloy plated steel sheet, stress concentration on the steel sheet caused by cracks in the plated layer is reduced by reducing the crystal grain size of the plated layer, in other words, by reducing the spangle. That is, when the crystal grain size of the plating layer is adjusted to a fine grain of less than 1 mm to densify the cracks generated in the plating layer due to strain during press working, a portion of stress concentration generated in the steel sheet immediately below the cracks has a high density. And many are generated. For this reason, stress concentration on the steel sheet immediately below the crack is dispersed, and work cracks are less likely to occur, and press workability is improved. On the other hand, the crystal grain of the plating layer has a grain size of 1 m.
When the grain size exceeds m, cracks in the plating layer caused by strain during press working become low in density and small in number with the increase in crystal grain size. That is, stress is locally concentrated on the steel sheet immediately below the crack in the plating layer, and the workability of the steel sheet is significantly impaired, and the workability is greatly reduced. Mold galling in the press working of the Zn-55% Al alloy plating layer occurs when the plating layer and the mold come into direct contact and slide. Therefore, in the case of a Zn-55% Al alloy-plated steel sheet in which a heat-resistant paint is pre-coated only on one side in order to utilize the heat resistance and heat reflection properties of the plating layer or to reduce the cost, In order to maintain a sufficient amount of press oil in the recesses on the surface of the plating layer to prevent the contact between the plating layer and the mold, the surface roughness of the plating layer should be Ra 0.
It is preferable to adjust the thickness in the range of 1 to 1 μm. When the surface roughness of the plating layer is in this range, the press oil held in the concave portion of the plating layer surface oozes out during the press working, and direct contact between the plating layer and the mold is prevented. If the surface roughness of the plating layer is less than R a 0.1 μm, a sufficient amount of press oil is not retained in the depressions on the surface of the plating layer, and the press oil retained in the depressions on the plating layer surface during press working. Even if there is oozing, the plating layer and the mold come into contact and slide. As a result, the plating layer is seized on the mold and galling occurs. Conversely, when the surface roughness exceeds Ra 1 μm, the convexities on the surface of the plating layer come into contact with the mold due to the high surface pressure, and the exudation to the crushed part becomes insufficient, so that mold seizure easily occurs. . In the case of Zn-55% Al alloy plated steel sheet with heat-resistant paint precoated only on one side, if the Vickers hardness of the plating layer is 100 or more,
Even if part of the plating layer slides in contact with the mold during press working, mold hardening is prevented due to the hardened plating layer. For plating layers with a Vickers hardness of less than 100, plating during press working If a part of the surface comes into contact with the mold and slides, there is a possibility that mold galling may occur. EXAMPLE 1 A cold-rolled steel strip for deep drawing having a thickness of 0.6 mm is continuously passed through a hot-dip plating bath having a composition of 45% by weight of Zn and 55% by weight of Al to perform hot-dip plating. gave. The coating weight was determined to be 90 g / m 2 (plate thickness: 12 μm) by gas wiping the steel sheet immediately after being lifted from the plating bath.
m). In the cooling step immediately after the plating, in the comparative example, the film was wound around a recoiler while being left to cool. On the other hand, in the example of the present invention, in the cooling step immediately after plating, the plating layer is rapidly cooled by liquid spray using water or an aqueous chloride solution, the crystal grain size is 1 mm or less, the surface roughness Ra is 0.1 to 1 μm, and the Vickers hardness is 10
The plating layer was adjusted to be 0 or more. Table 1 shows the physical properties of the formed Zn-55% Al alloy plating layers. [0010] The Zn on which each plating layer shown in Table 1 is formed
Using a -55% Al alloy-plated steel strip as a coating base plate, apply a fluorine-based heat-resistant and non-adhesive paint to both sides of the steel strip after degreasing treatment in a continuous coating line so that the dry film thickness is 15 μm (one side), and heat it. It was fired at a temperature of 400 ° C. The stretchability of the Zn-55% Al alloy plated steel sheet subjected to the heat-resistant coating was investigated. For the test, a die with a lock bead and a blank holder were used. Pure overhang was performed under the conditions of a blank diameter of 250 mm, a punch diameter of 200 mm, a punch shoulder radius of 10 mm, a die shoulder radius of 3 mm, a wrinkle holding force of 250 KN, and no press oil. The overhang height at which cracks, breaks and the like did not occur was determined. As can be seen from the survey results in Table 2, the double-sided heat-resistant coated Zn-55% Al alloy-plated steel sheet according to the present invention has a working height of 45 mm or more in all cases, and has extremely excellent overhang. Workability was shown. In contrast,
The double-sided heat-resistant coated Zn-55% Al alloy-plated steel sheets as comparative examples each have a processing height of 22 mm or less,
Overhanging workability was poor. This is presumed to be the result of the fact that cracks in the plating layer caused by distortion during press working were reduced in density and few due to coarsening of crystal grains, and stress was locally concentrated on the steel sheet immediately below the cracks in the plating layer. Is done. [0013] Example 2 The same Zn-55% Al alloy-plated steel strip as in Table 1 was used as a coating base plate, and fluorine was applied to one side of a degreased steel strip in a continuous coating line so that the dry film thickness was 15 μm. A heat-resistant and non-adhesive paint was applied and baked at a heating temperature of 400 ° C. For the Zn-55% Al alloy plated steel sheet coated on one side with heat resistance of the present invention example and the comparative example, using a low-viscosity volatile press oil S-100J (manufactured by Sugimura Chemical Industry Co., Ltd.), the plated surface is on the die side. The drawability and galling resistance were investigated. A blank with a diameter of 380 mm was used for the test, and a punch diameter of 200 mm and a punch shoulder radius of 10 were used.
mm, die shoulder radius of 5 mm, and drawing height of 100 mm, changing the plate holding force to perform cylindrical drawing, and obtaining the range of the plate holding force in which wrinkles and cracks do not occur, that is, the range of the so-called moldable plate holding force. At the same time, the state of mold galling was observed. As can be seen from the investigation results in Table 3, the steel sheet in which the heat-resistant paint is coated on one side of the Zn-55% Al alloy plating layer according to the present invention has a formable sheet pressing force range of 10%.
It was as wide as 0 to 280 kN, and exhibited extremely excellent drawability and galling resistance. In contrast, the single-sided heat-resistant coated Zn-55% Al alloy plated steel sheet, in which the plated layer was allowed to cool as a comparative example, had a formable sheet pressing force range of 100 to 150 kN.
And the drawability and galling resistance were inferior. This is because cracks in the plating layer caused by distortion during press working are low in density and few due to coarsening of crystal grains, and stress is locally concentrated on the steel sheet immediately below the cracks in the plating layer and the steel sheet breaks. It is presumed that this is a result of the combination of the fact that the plating becomes easy and the plating layer is seized on the mold and the frictional resistance is remarkably increased. [0016] As described above, the heat-resistant coated Zn-55% Al alloy-plated steel sheet of the present invention is generated at the time of press working by adjusting the crystal grain size of the plating layer to 1 mm or less. The places where the stress is concentrated are dispersed, and processing cracks due to local stress concentration are less likely to occur. For this reason, a heat-resistant coated Zn-55% Al alloy plated steel sheet having more than twice the drawability and stretchability as compared with the conventional heat-resistant coated Zn-55% Al alloy coated steel sheet can be obtained. In addition to regulating the crystal grain size to 1 mm or less, by adjusting the plating layer to have a surface roughness Ra of 0.1 to 1 μm and a Vickers hardness of 100 or more, the galling resistance is remarkably improved, and the friction is improved. Resistance can be reduced. For this reason, even if a volatile low-viscosity press oil is used at the time of press working, the adhesion of the plating layer to the mold is suppressed, and the continuous press workability with less maintenance frequency of the mold is excellent. A single-sided heat-resistant coated Zn-55% Al alloy plated steel sheet is obtained. Moreover, the plating layer is Zn-55
% Al alloy, which is superior in heat resistance and durability as compared with general Zn-plated steel sheets. It is used in a wide range of fields such as inner boxes, home appliances, and kitchen products.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 菅原 広志 千葉県市川市高谷新町７番１号 日新製 鋼株式会社技術研究所内 (56)参考文献 特開 平８−224829（ＪＰ，Ａ) 特開 平６−158256（ＪＰ，Ａ) 特開 平７−136701（ＪＰ，Ａ) 特開 平７−316763（ＪＰ，Ａ) 特開 昭62−23976（ＪＰ，Ａ) 特開 平４−94768（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C23C 2/12 C23C 2/26 C23C 2/40 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Sugawara 7-1 Takayashinmachi, Ichikawa-shi, Chiba Nisshin Steel Co., Ltd. Technical Research Institute (56) References JP-A-8-224829 (JP, A) JP-A-6-158256 (JP, A) JP-A-7-136701 (JP, A) JP-A-7-316763 (JP, A) JP-A-62-23976 (JP, A) JP-A-4-94768 (JP JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C23C 2/12 C23C 2/26 C23C 2/40
Claims (1)
１〜１μｍ及び硬さ１００以上に調整したＺｎ−５５％
Ａｌ合金めっき層の上に耐熱塗装が施されているプレス
加工性に優れた耐熱塗装Ｚｎ−５５％Ａｌ合金めっき鋼
板。(57) [Claims 1] A crystal grain size of 1 mm or less and a surface roughness Ra 0.
Zn-55% adjusted to 1-1 μm and hardness of 100 or more
A heat-resistant coated Zn-55% Al alloy-plated steel sheet with excellent press workability, in which a heat-resistant coating is applied on the Al alloy plating layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30012696A JP3527374B2 (en) | 1996-11-12 | 1996-11-12 | Heat-resistant painted Zn-55% Al alloy plated steel sheet with excellent press workability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30012696A JP3527374B2 (en) | 1996-11-12 | 1996-11-12 | Heat-resistant painted Zn-55% Al alloy plated steel sheet with excellent press workability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10140314A JPH10140314A (en) | 1998-05-26 |
| JP3527374B2 true JP3527374B2 (en) | 2004-05-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30012696A Expired - Fee Related JP3527374B2 (en) | 1996-11-12 | 1996-11-12 | Heat-resistant painted Zn-55% Al alloy plated steel sheet with excellent press workability |
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| JP (1) | JP3527374B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4921636B2 (en) * | 2000-12-25 | 2012-04-25 | 株式会社東芝 | Alloy plate for panel pin, panel pin, and picture tube |
| KR100456774B1 (en) * | 2002-01-05 | 2004-11-10 | 동부제강주식회사 | A manufacturing method of the Hot-Dip Aluminized Steel Sheet which has a excellent surface appearance |
| JP2008156729A (en) * | 2006-12-26 | 2008-07-10 | Nisshin Steel Co Ltd | Zn-Al-BASED PLATING-COATED STEEL SHEET EXCELLENT IN UNBENDING RESISTANCE, AND ITS PRODUCTION METHOD |
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1996
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| JPH10140314A (en) | 1998-05-26 |
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