JP2006299350A - Steel sheet having excellent die galling resistance and corrosion resistance after coating - Google Patents

Steel sheet having excellent die galling resistance and corrosion resistance after coating Download PDF

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JP2006299350A
JP2006299350A JP2005123048A JP2005123048A JP2006299350A JP 2006299350 A JP2006299350 A JP 2006299350A JP 2005123048 A JP2005123048 A JP 2005123048A JP 2005123048 A JP2005123048 A JP 2005123048A JP 2006299350 A JP2006299350 A JP 2006299350A
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steel sheet
coating
corrosion resistance
compound
manganese phosphate
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Seiji Nakajima
清次 中島
Shinji Otsuka
真司 大塚
Satoshi Ando
聡 安藤
Yoshiharu Sugimoto
芳春 杉本
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JFE Steel Corp
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JFE Steel Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel sheet such as a cold-rolled steel sheet and a hot rolled steel sheet used as a steel sheet for automobiles highly compatibly having die galling resistance and corrosion resistance after coating and to provide a steel sheet satisfying die galling resistance and corrosion resistance after coating of a high strength steel sheet. <P>SOLUTION: In the steel sheet having excellent die galling resistance and corrosion resistance after coating, the surface of the steel sheet is coated with a compound consisting essentially of manganese phosphate in 2 to 50% area ratio. In the steel sheet, the compound consisting essentially of manganese phosphate is a granular compound having ≤3 μm average particle diameter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、耐型かじり性および塗装後耐食性に優れた鋼板に関し、例えば自動車用材料として用いられる耐型かじり性および塗装後耐食性に優れた冷延鋼板または熱延鋼板に関する。   The present invention relates to a steel sheet excellent in mold galling resistance and post-painting corrosion resistance, for example, a cold-rolled steel sheet or hot-rolled steel sheet excellent in mold galling resistance and post-coating corrosion resistance used as a material for automobiles.

鋼板は安価な金属材料であるため、自動車、家電、建材等の分野において広く用いられている。特に、自動車分野においては、鋼板が他の金属材料と比較して優れたプレス成形性、化成処理性、塗装後耐食性を有することから、依然として自動車用材料の主流となっている。近年、自動車業界においては、燃費向上および排出ガス削減の観点から自動車の軽量化が進んでおり、さらに衝突安全性向上のニーズともあいまって、高強度鋼板の使用が急増している。   Since steel plates are inexpensive metal materials, they are widely used in fields such as automobiles, home appliances, and building materials. In particular, in the automotive field, steel sheets are still the mainstream material for automobiles because they have superior press formability, chemical conversion properties and post-coating corrosion resistance compared to other metal materials. In recent years, in the automobile industry, the weight of automobiles has been reduced from the viewpoint of improving fuel efficiency and reducing exhaust gas, and the use of high-strength steel sheets has been rapidly increasing in conjunction with the need for improved collision safety.

高強度鋼板は鋼中元素としてSi、Mn等が添加された鋼板であり、これらの元素が鋼板表面に分布することにより化成処理性が劣化し、ひいては塗装後耐食性が著しく劣化することが従来から知られている。一方、高強度鋼板をプレス成形する際には、成形荷重が増大するのみならず、局部的な高面圧部が生じることにより型かじりが発生する問題があり、従来から耐型かじり性および塗装後耐食性に優れた高強度鋼板の開発が切望されていた。   A high-strength steel sheet is a steel sheet to which Si, Mn, etc. are added as elements in the steel, and these elements are distributed on the surface of the steel sheet, so that the chemical conversion processability is deteriorated and the corrosion resistance after coating is significantly deteriorated. Are known. On the other hand, when high-strength steel sheets are press-formed, not only the forming load increases, but also there is a problem that die galling occurs due to the occurrence of local high surface pressure parts. The development of a high-strength steel sheet with excellent post-corrosion resistance has been desired.

鋼板表面を改質することによりその特性を向上させようとする技術としては、例えば、特許文献1において、鋼板表面にZn、Pの酸化物と第3元素群のMn、Ni、Mg、Fe、Co、Alの1種または2種以上の酸化物からなる皮膜を生成することにより化成処理性、潤滑性、接着剤適合性を向上させる技術が開示されている。   As a technique for improving the characteristics of the steel sheet by modifying the steel sheet surface, for example, in Patent Document 1, Zn, P oxide and third element group Mn, Ni, Mg, Fe, A technique for improving chemical conversion property, lubricity, and adhesive compatibility by forming a film composed of one or more oxides of Co and Al is disclosed.

しかしながら、上記技術は鋼板表面に形成した皮膜を化成処理液中でほぼ完全に溶解させることにより化成処理性を阻害しないことを意図した技術であり、その化成処理性は皮膜を施していない原板の化成処理性レベルより向上するものではなく、Si、Mn等の添加元素量がさらに増大している近年の高強度鋼板の化成処理性を満足させるにはまったく至っておらず、ひいては塗装後耐食性も甚だ不十分である。また、上記の皮膜では、皮膜自体の強靭性が不足しているため、耐型かじり性の改善効果についても甚だ不十分であった。   However, the above technique is a technique intended to not inhibit the chemical conversion treatment by dissolving the film formed on the surface of the steel sheet almost completely in the chemical conversion treatment liquid. It does not improve from the chemical conversion treatment level, and has not yet reached the chemical conversion treatment performance of recent high-strength steel sheets in which the amount of additive elements such as Si and Mn is further increased, and as a result, the corrosion resistance after coating is also significant. It is insufficient. In addition, the above-mentioned coating film has insufficient toughness of the coating film itself, so that the effect of improving mold galling resistance is very insufficient.

また、本発明で意図しているところの冷延鋼板または熱延鋼板に関する技術とは異なるが、亜鉛系めっき鋼板にMn酸化物、リン酸およびその他酸化物からなるMn系酸化物皮膜を被覆した鋼板が特許文献2に開示されている。しかしながら、この技術は、プレス時における軟質な亜鉛めっき層のダイスへのかじりを抑制しようとする技術であり、これを達成するために摩擦係数の低減のみを狙った技術である。これに対し、本発明で対象とする冷延鋼板または熱延鋼板の耐型かじり性は、例えば500MPa以上の高面圧においても同種金属である鋼板と金型の間において型かじりが発生しないことが要求されるものであり、亜鉛系めっき鋼板よりも格段に厳しい要求に対応しようとするものである。また前記先行特許で提案されている皮膜は、化成処理液中で溶解するために化成処理性に悪影響を与えないというものであり、本発明で意図するような積極的に塗装後耐食性を向上させる目的のものではない。
特開平9−53189号公報 特公平7−13307号公報
Moreover, although it is different from the technology related to the cold-rolled steel sheet or hot-rolled steel sheet intended in the present invention, a zinc-based plated steel sheet is coated with a Mn-based oxide film made of Mn oxide, phosphoric acid and other oxides. A steel sheet is disclosed in Patent Document 2. However, this technique is a technique for suppressing the galling of the soft galvanized layer to the die during pressing, and is a technique aimed only at reducing the friction coefficient in order to achieve this. On the other hand, the mold galling resistance of the cold-rolled steel sheet or hot-rolled steel sheet that is the subject of the present invention is such that no galling occurs between the steel plate and the mold that are the same metal even at a high surface pressure of 500 MPa or more. Therefore, it is intended to meet requirements that are much stricter than galvanized steel sheets. Further, the coating proposed in the above-mentioned prior patent does not adversely affect the chemical conversion treatment property because it dissolves in the chemical conversion treatment solution, and positively improves the post-coating corrosion resistance as intended in the present invention. It is not the purpose.
JP-A-9-53189 Japanese Patent Publication No.7-13307

上述のように、従来の技術では冷延鋼板や熱延鋼板の耐型かじり性と塗装後耐食性を高度に両立する技術は確立されておらず、特に、高強度鋼板の耐型かじり性と塗装後耐食性を満足する技術は存在しなかった。   As described above, the conventional technology has not established a technology that achieves a high level of both anti-corrosion resistance and cold corrosion resistance of cold-rolled steel sheets and hot-rolled steel sheets. There was no technology that satisfied post-corrosion resistance.

本発明はこのような実情に鑑み、特に自動車用鋼板として用いられる冷延鋼板および熱延鋼板の耐型かじり性と塗装後耐食性を高度に両立する技術を提供することを目的とする。さらに、近年の高強度鋼板は、Si、Mn等の元素が多量に添加されているために良好な塗装後耐食性の確保がより一層困難となってきており、また強度増大にともない型かじりも発生しやすくなっていることから、高強度鋼板の耐型かじり性と塗装後耐食性をも満足させることが可能な鋼板を提供することを目的とする。   In view of such a situation, an object of the present invention is to provide a technology that achieves a high level of both anti-galling resistance and post-coating corrosion resistance of a cold-rolled steel sheet and a hot-rolled steel sheet used as a steel sheet for automobiles. Furthermore, high strength steel sheets in recent years have become more difficult to ensure good post-coating corrosion resistance due to the addition of a large amount of elements such as Si and Mn, and mold galling also occurs as the strength increases. Therefore, an object of the present invention is to provide a steel sheet that can satisfy both the anti-galling resistance and the post-coating corrosion resistance of a high-strength steel sheet.

本発明者らは、高強度鋼板の塗装後耐食性を改善することを目的として、鋼板表面上に被覆した種々の化合物の効果について鋭意検討を行った。その結果、これまで耐型かじり性に有効であるとされてきたリン酸マンガン系皮膜をそのまま適用した場合には塗装後耐食性が劣悪となるものの、リン酸マンガンを主体とする化合物を鋼板表面上に適正な被覆面積率となるように制御して被覆した場合には、塗装後耐食性をむしろ向上させることが可能であることを新規に見出した。さらに、耐型かじり性についても、従来は検討されていなかった本発明の被覆面積率領域において、リン酸マンガンを主体とする化合物が格段の向上効果を示すことを新規に見出し本発明に至った。   In order to improve the post-coating corrosion resistance of a high-strength steel sheet, the present inventors have intensively studied the effects of various compounds coated on the steel sheet surface. As a result, when the manganese phosphate coating, which has been considered effective for mold galling resistance, is applied as it is, the corrosion resistance after coating is deteriorated, but the compound mainly composed of manganese phosphate is added to the steel sheet surface. It was newly found that the corrosion resistance after coating can be rather improved when the coating is controlled so as to have an appropriate covering area ratio. Furthermore, with regard to mold galling resistance, it was newly found out that a compound mainly composed of manganese phosphate shows a remarkable improvement effect in the covering area ratio region of the present invention that has not been studied so far, and has led to the present invention. .

上記課題を解決する本発明の手段は、次の通りである。   Means of the present invention for solving the above problems are as follows.

(1)鋼板表面上にリン酸マンガンを主体とする化合物が2〜50%の面積率で被覆されていることを特徴とする耐型かじり性および塗装後耐食性に優れた鋼板である。   (1) A steel sheet excellent in mold galling resistance and post-coating corrosion resistance, characterized in that a compound mainly composed of manganese phosphate is coated on the steel sheet surface at an area ratio of 2 to 50%.

(2)リン酸マンガンを主体とする化合物が、平均粒径が3μm以下の粒状化合物であることを特徴とする(1)記載の耐型かじり性および塗装後耐食性に優れた鋼板である。   (2) The steel sheet excellent in mold galling resistance and post-coating corrosion resistance, wherein the compound mainly composed of manganese phosphate is a granular compound having an average particle diameter of 3 μm or less.

本発明は、耐型かじり性、塗装後耐食性を高度に両立する鋼板を提供するものであり、特に高強度鋼板の耐型かじり性、塗装後耐食性を両立させる極めて有効な技術であり、工業的に極めて価値の高いものである。   The present invention provides a steel sheet that is highly compatible with mold galling resistance and post-coating corrosion resistance, and is an extremely effective technology that achieves both galling resistance and post-coating corrosion resistance of a high-strength steel sheet. It is extremely valuable.

以下、本発明について発明に至った経緯とともに説明する。   The present invention will be described below together with the background to the invention.

一般に、塗装後耐食性を改善するための手段としては、自動車メーカーにおける化成処理すなわちリン酸亜鉛処理によって形成される化成処理結晶をスケやムラのない緻密なものとすることが有効であると従来から考えられてきた。一方で、自動車メーカーにおける化成処理液も近年進歩しており、例えば表面調整剤の改良による化成処理結晶の緻密化とこれにともなう皮膜重量の低減や、リン酸亜鉛処理に代わる次世代の化成処理液も提案されている。   In general, as a means for improving the corrosion resistance after painting, it is effective that the chemical conversion treatment crystal formed by the chemical conversion treatment in the automobile manufacturer, that is, the zinc phosphate treatment, is dense without any scum or unevenness. Has been considered. On the other hand, chemical treatment liquids at automobile manufacturers have also made progress in recent years. For example, denaturation of chemical conversion treatment crystals by improving surface conditioners and the reduction of coating weight accompanying this, and next-generation chemical treatment to replace zinc phosphate treatment Liquids have also been proposed.

すなわち、最終製品である自動車ボディーを考えた場合、必要な特性は塗装後耐食性であり、この塗装後耐食性を良好とすることが可能であれば、従来から言われてきた化成処理性は必ずしも必須の特性ではないわけである。   That is, when considering the automobile body that is the final product, the necessary characteristic is post-coating corrosion resistance. If this post-coating corrosion resistance can be improved, the chemical conversion processability that has been said so far is indispensable. It is not a characteristic of.

そこで本発明者らは、まず高強度鋼板の塗装後耐食性を改善することを目的として、鋼板表面上に被覆した種々の化合物の効果について鋭意検討を行った。その結果、これまで耐型かじり性に有効であるとされてきたリン酸マンガン系皮膜をそのまま適用した場合には塗装後耐食性が劣悪となるものの、リン酸マンガンを主体とする化合物を鋼板表面上に適正な被覆面積率となるように制御して被覆した場合には、塗装後耐食性をむしろ向上させることが可能であることを新規に見出した。さらに、耐型かじり性についても、従来は検討されていなかった本発明の被覆面積率領域において、リン酸マンガンを主体とする化合物が格段の向上効果を示すことを新規に見出した。   Therefore, the present inventors first conducted intensive studies on the effects of various compounds coated on the surface of the steel sheet for the purpose of improving the post-coating corrosion resistance of the high-strength steel sheet. As a result, when the manganese phosphate coating, which has been considered effective for mold galling resistance, is applied as it is, the corrosion resistance after coating becomes poor, but the compound mainly composed of manganese phosphate is added to the steel sheet surface. It was newly found that the corrosion resistance after coating can be rather improved when the coating is controlled so as to have an appropriate covering area ratio. Furthermore, it has been newly found that a compound mainly composed of manganese phosphate exhibits a marked improvement effect in the area of coverage area of the present invention which has not been studied in the past with respect to mold galling resistance.

リン酸マンガンを主体とする化合物を所定の面積率で鋼板表面に被覆することにより塗装後耐食性が向上する理由としては、以下のように考えている。   The reason why the corrosion resistance after coating is improved by coating a steel sheet surface with a compound mainly composed of manganese phosphate at a predetermined area ratio is considered as follows.

塗装後耐食性は、これまでの知見によれば、主として自動車メーカーでの化成処理工程において形成されるリン酸亜鉛結晶にスケやムラがなければよいものと考えられてきた。さらに、形成されるリン酸亜鉛結晶の組成としては、P比(フォスフォフィライトの強度をP、ホパイトの強度をHとしたときのP/(P+H)の値)が高いほどよいとされてきた。   Corrosion resistance after coating has been considered to be good if the zinc phosphate crystals formed mainly in the chemical conversion treatment process at an automobile manufacturer are free of scum and unevenness according to the knowledge so far. Furthermore, the composition of the zinc phosphate crystal formed is considered to be better as the P ratio (P / (P + H) value where P is the intensity of phosphophyllite and H is the intensity of the phosphite) is higher. It was.

一方、鋼板の全面にリン酸マンガン系皮膜を施した鋼板は、自動車メーカーでの化成処理工程においてリン酸亜鉛結晶がほとんど形成されないため、化成処理やこれに引き続く塗装が施される用途の鋼板には使用されてこなかった。   On the other hand, a steel plate with a manganese phosphate coating on the entire surface of the steel plate has almost no zinc phosphate crystals formed during the chemical conversion treatment process at an automobile manufacturer. Has not been used.

しかしながら、本発明者らの検討によれば、リン酸マンガンを主体とする化合物を鋼板表面の一部に被覆した鋼板を自動車メーカーでの化成処理に供した場合、この化合物上にリン酸亜鉛結晶が付着することはないものの、鋼板露出部のエッチング性を高めることにより化成処理反応を促進し、より緻密でスケやムラのないリン酸亜鉛結晶が形成され、特にSiやMn等の元素が表面に濃化して不活性となっている高強度鋼板においてより顕著な効果を示すことを見出した。すなわち、鋼板露出部において化成処理反応を促進してリン酸亜鉛結晶を緻密化させることが、塗装後耐食性を向上させる一つの作用であることを見出した。   However, according to the study by the present inventors, when a steel sheet in which a compound mainly composed of manganese phosphate is coated on a part of the steel sheet surface is subjected to a chemical conversion treatment at an automobile manufacturer, a zinc phosphate crystal is formed on the compound. Although it does not adhere, the chemical conversion treatment reaction is promoted by increasing the etching property of the exposed steel sheet, and more dense zinc phosphate crystals with no scale or unevenness are formed. It has been found that a high-strength steel sheet that is concentrated and inactive exhibits a more remarkable effect. That is, it has been found that promoting the chemical conversion reaction in the exposed steel plate portion and densifying the zinc phosphate crystals is one effect of improving the post-coating corrosion resistance.

さらに、リン酸マンガンを主体とする化合物と電着塗膜との密着性について検討した結果、リン酸マンガンを主体とする化合物が鋼板全面を覆っている場合には密着性は極めて不良であるが、鋼板の一部を被覆している場合にはむしろ密着性の向上効果が認められ、たとえリン酸マンガンを主体とする化合物の上にリン酸亜鉛結晶が付着することがなくとも、リン酸マンガンを主体とする化合物自体が電着塗膜との密着性を向上させることにより、塗装後耐食性を向上させることを新規に見出した。   Furthermore, as a result of examining the adhesion between the compound mainly composed of manganese phosphate and the electrodeposition coating film, the adhesion is extremely poor when the compound mainly composed of manganese phosphate covers the entire surface of the steel sheet. In the case where a part of the steel sheet is coated, an effect of improving the adhesion is recognized. Even if zinc phosphate crystals do not adhere on the compound mainly composed of manganese phosphate, manganese phosphate It has been newly found that the compound itself mainly composed of improves the corrosion resistance after coating by improving the adhesion with the electrodeposition coating film.

すなわち、リン酸マンガンを主体とする化合物を鋼板表面の一部に被覆した鋼板は、鋼板露出部において形成されるリン酸亜鉛結晶を緻密化する作用と、リン酸マンガンを主体とする化合物自体が電着塗膜との密着性を向上させる作用の相乗効果によって塗装後耐食性を向上させるものと考えられる。   That is, the steel sheet in which a part of the steel plate surface is coated with a compound mainly composed of manganese phosphate has an effect of densifying the zinc phosphate crystal formed in the exposed part of the steel sheet and the compound itself mainly composed of manganese phosphate. It is thought that the post-coating corrosion resistance is improved by the synergistic effect of improving the adhesion with the electrodeposition coating film.

一方、リン酸マンガンを主体とする化合物を鋼板表面の一部に被覆した鋼板の耐型かじり性はこれまで検討されてこなかったが、本発明者らは、極めてわずかな被覆面積率であっても顕著な耐型かじり性向上効果を示すことを新規に見出した。耐型かじり性を向上させるメカニズムは、リン酸マンガンを主体とする化合物が硬質で高融点の化合物であり、これが鋼板と金型との直接接触を防止し金属凝着を抑制する効果、および油膜を保持する効果によるものと考えられる。ところが、これらの効果を発現させるためには、リン酸マンガンを主体とする化合物が必ずしも鋼板全面を覆っている必要はなく、鋼板表面の一部に被覆されていれば良いこと、さらに油膜の保持効果に至っては、リン酸マンガンを主体とする化合物が鋼板全面を覆っているよりも、むしろ適正な面積率の範囲で被覆されている方が効果的であることが判明した。   On the other hand, although the mold galling resistance of a steel sheet in which a compound mainly composed of manganese phosphate is coated on a part of the steel sheet surface has not been studied so far, the present inventors have a very small coverage area ratio. Has also been found to show a remarkable effect of improving the galling resistance. The mechanism to improve mold galling resistance is that the compound mainly composed of manganese phosphate is a hard and high melting point compound, which prevents the direct contact between the steel plate and the mold and suppresses metal adhesion, and oil film This is thought to be due to the effect of maintaining However, in order to express these effects, the compound mainly composed of manganese phosphate does not necessarily have to cover the entire surface of the steel sheet, and it is only necessary to cover a part of the surface of the steel sheet. In terms of the effect, it has been found that it is more effective that the compound mainly composed of manganese phosphate is coated in an appropriate area ratio range rather than covering the entire surface of the steel sheet.

さらに、リン酸マンガンを主体とする化合物の形状が粒状であり、その粒径が小さいほど、耐型かじり性および塗装後耐食性に優れることも判明した。これは、被覆面積率が同じであっても、粒径が小さいほど粒状化合物の数が増大することに起因する。すなわち、耐型かじり性については、粒状化合物がコロの作用を発現し、その数が多いほど潤滑効果が増大するためである。また、塗装後耐食性については、粒状化合物の数が増大するほど鋼板露出部のエッチング性が高まって化成処理反応が促進され、鋼板露出部に形成されるリン酸亜鉛結晶が緻密化する作用と、粒状のリン酸マンガンを主体とする化合物自体が電着塗膜との密着性を向上させる作用の相乗効果によるものである。本発明は、これらの知見に基づいてなされたものである。   Furthermore, it has also been found that the compound mainly composed of manganese phosphate has a granular shape, and the smaller the particle size, the better the resistance to mold galling and the corrosion resistance after coating. This is due to the fact that the number of granular compounds increases as the particle size decreases even if the coverage area ratio is the same. That is, with respect to mold galling resistance, the granular compound exhibits a roller action, and the greater the number, the greater the lubricating effect. In addition, as for the corrosion resistance after coating, as the number of granular compounds increases, the etching property of the steel plate exposed portion increases and the chemical conversion reaction is promoted, and the action of the zinc phosphate crystals formed on the steel plate exposed portion becomes dense, The compound itself mainly composed of granular manganese phosphate is due to a synergistic effect of improving the adhesion with the electrodeposition coating film. The present invention has been made based on these findings.

以下、本発明をさらに詳細に説明する。   Hereinafter, the present invention will be described in more detail.

本発明で使用する鋼板としては特に限定されるものではないが、熱延鋼板、冷延鋼板等の鋼板が例示される。なかでも自動車用材料として使用頻度の高い鋼板である、酸洗処理により黒皮を除去した熱延鋼板や、焼鈍処理により材質を調整した冷延鋼板が好適に使用される。また、鋼板の強度レベルについても限定されるものではなく、引張強度が300MPa以下の軟鋼板から引張強度が1000MPaを超えた高強度鋼板に至るまで、すべての鋼板に適用可能である。鋼板の板厚についても何ら限定されるものではなく、例えば0.2〜5mm程度の板厚の鋼板が適用可能である。   Although it does not specifically limit as a steel plate used by this invention, Steel plates, such as a hot rolled steel plate and a cold rolled steel plate, are illustrated. Among these, a hot-rolled steel sheet that has been frequently used as a material for automobiles, a hot-rolled steel sheet from which black skin has been removed by pickling treatment, and a cold-rolled steel sheet whose material has been adjusted by annealing treatment are preferably used. Further, the strength level of the steel plate is not limited, and the steel plate can be applied to all steel plates ranging from a mild steel plate having a tensile strength of 300 MPa or less to a high strength steel plate having a tensile strength exceeding 1000 MPa. The plate thickness of the steel plate is not limited at all. For example, a steel plate having a thickness of about 0.2 to 5 mm is applicable.

本発明においては、鋼板表面上にリン酸マンガンを主体とする化合物が2〜50%の面積率で被覆されていることが必要である。   In the present invention, it is necessary that the steel plate surface is coated with a compound mainly composed of manganese phosphate at an area ratio of 2 to 50%.

リン酸マンガンを主体とする化合物の被覆面積率が2%未満では耐型かじり性、塗装後耐食性ともに向上効果が不十分である。耐型かじり性が不十分な理由は、硬質で高融点のリン酸マンガンを主体とする化合物が、鋼板と金型との直接接触を防止して金属凝着を抑制する効果、および油膜を保持して潤滑性を向上させる効果が不十分であることによる。塗装後耐食性が不十分な理由は、リン酸マンガンを主体とする化合物が鋼板露出部のエッチング性を高め、リン酸亜鉛結晶を緻密化させる効果に乏しいことと、リン酸マンガンを主体とする化合物自体が電着塗膜との密着性を向上させる効果に乏しいことによる。   If the covering area ratio of the compound mainly composed of manganese phosphate is less than 2%, the effect of improving both mold galling resistance and post-coating corrosion resistance is insufficient. The reason why mold galling resistance is insufficient is that a hard, high melting point manganese phosphate-based compound prevents the direct contact between the steel plate and the mold and suppresses metal adhesion, and maintains an oil film. This is because the effect of improving lubricity is insufficient. The reason why the corrosion resistance after painting is insufficient is that the compound mainly composed of manganese phosphate is poor in the effect of enhancing the etching property of the exposed portion of the steel sheet and densifying the zinc phosphate crystal, and the compound mainly composed of manganese phosphate. This is because the effect itself of improving the adhesion with the electrodeposition coating film is poor.

一方、リン酸マンガンを主体とする化合物の被覆面積率が50%を超えると、耐型かじり性、塗装後耐食性ともに劣化する。耐型かじり性が劣化するのは、油膜を保持して潤滑性を向上させる効果が劣化するためと考えられる。一方、塗装後耐食性が劣化するのは、鋼板露出部が少なくなるため、この部分でのエッチング性がかえって劣化し、この部分に形成されるリン酸亜鉛結晶が粗大化するため、およびリン酸マンガンを主体とする化合物自体が有する電着塗膜との密着性向上効果もアンカー効果の低下にともない劣化するためと考えられる。   On the other hand, when the covering area ratio of the compound mainly composed of manganese phosphate exceeds 50%, both mold galling resistance and post-coating corrosion resistance deteriorate. The reason why mold galling resistance is deteriorated is considered to be that the effect of retaining the oil film and improving the lubricity deteriorates. On the other hand, the corrosion resistance after coating is deteriorated because the exposed portion of the steel sheet is reduced, the etching property in this part is deteriorated, and the zinc phosphate crystal formed in this part is coarsened, and the manganese phosphate This is considered to be because the effect of improving the adhesion with the electrodeposition coating film possessed by the compound comprising mainly the azo compound deteriorates as the anchor effect decreases.

本発明では、リン酸マンガンを主体とする化合物の被覆面積率が2〜50%の範囲であることが必須用件であり、この被覆面積率を満足していれば、リン酸マンガンを主体とする化合物の付着量については特に限定されるものではない。リン酸マンガンを主体とする化合物の付着量は、その被覆面積率以外に、化合物の形状、平均粒径、分布状態など複数の因子に依存するため、被覆面積率によって一義的に決定するものではない。しかしながら、本発明者らの検討結果によると、リン酸マンガンを主体とする化合物の付着量が1.0g/mを超えると、その被覆面積率が50%を超えてしまう場合がほとんどであるため好ましくなく、また付着量が0.02g/m未満では、その被覆面積率が2%未満となる場合がほとんどであるため好ましくない。従って、リン酸マンガンを主体とする化合物の付着量の好適範囲は0.02〜1.0g/mであり、より好ましくは0.02〜0.8g/mである。 In the present invention, it is an essential requirement that the covering area ratio of the compound mainly composed of manganese phosphate is in the range of 2 to 50%, and if this covering area ratio is satisfied, the covering area ratio is mainly composed of manganese phosphate. There are no particular restrictions on the amount of the compound to be adhered. The adhesion amount of the compound mainly composed of manganese phosphate depends on a number of factors such as the shape of the compound, the average particle size, and the distribution state in addition to the coverage area ratio, and therefore it is not uniquely determined by the coverage area ratio. Absent. However, according to the examination results of the present inventors, when the adhesion amount of the compound mainly composed of manganese phosphate exceeds 1.0 g / m 2 , the covering area ratio often exceeds 50%. For this reason, it is not preferable, and an adhesion amount of less than 0.02 g / m 2 is not preferable because the coverage area ratio is almost less than 2%. Accordingly, the preferred range of coating weight compounds mainly manganese phosphate is 0.02~1.0g / m 2, more preferably from 0.02~0.8g / m 2.

リン酸マンガンを主体とする化合物としては、例えば、リン酸マンガン(Mn(PO)およびこの水和物が例示される。ただし、この化合物に限定されるものではなく、化合物中にリン酸(PO)、およびマンガン(Mn)の両者を必須の構成成分として含有する化合物であればよく、結晶質であっても非晶質であってもよい。また、この化合物を構成するMnの一部が、たとえばFe、Ni、Co、Mgなどによって置換された構造の化合物であってもよい。ただし、Znによって置換された場合には化合物が軟質化し耐型かじり性が劣化するため、本発明の化合物はZnを含有しないこととする。 Examples of the compound mainly composed of manganese phosphate include manganese phosphate (Mn 3 (PO 4 ) 2 ) and hydrates thereof. However, the compound is not limited to this compound, and may be any compound that contains both phosphoric acid (PO 4 ) and manganese (Mn) as essential constituents in the compound. It may be crystalline. Further, a compound having a structure in which a part of Mn constituting this compound is substituted with, for example, Fe, Ni, Co, Mg, or the like may be used. However, the compound of the present invention does not contain Zn because the compound is softened and the galling resistance deteriorates when substituted with Zn.

本発明において、鋼板表面上のリン酸マンガンを主体とする化合物の被覆面積率の算出方法は特に限定されるものではないが、例えば以下の方法が好適に用いられる。すなわち、SEM(走査型電子顕微鏡)等の表面観察装置を用いて、例えば100倍から5000倍程度、より好ましくは500倍から2000倍程度の倍率で表面観察を行う。あまり高倍率で観察を行うと平均的な情報が得られにくく、逆にあまり低倍率で観察を行うとリン酸マンガンを主体とする化合物の観察自体が困難となる。このような方法で観察を行い、目視や画像処理によりリン酸マンガンを主体とする化合物の被覆面積率を算出すればよい。必要に応じEDX分析(エネルギー分散型X線分析)等を併用して、観察される化合物がリン酸マンガンを主体とする化合物であることを確認することも好適である。また、EPMA(電子線プローブマイクロアナライザー)やAES(オージェ電子分光分析)等の装置を使用してP、Mn、O等の元素をマッピングすることにより被覆面積率を算出することも可能である。また、鋼板表面上のリン酸マンガンを主体とする化合物の被覆面積率に関する平均的な情報を得るためには、上記の方法により少なくとも5視野以上の領域について観察を行うのが好ましく、より好ましくは10視野以上の領域について観察を行い、その平均値を被覆面積率とすればよい。なお、観察する部位としては、正常な処理が行われた鋼板の代表的な部位を観察すべきであり、鋼帯のエッジ部や、鋼帯の欠陥部等は観察すべきではない。   In the present invention, the method for calculating the covering area ratio of the compound mainly composed of manganese phosphate on the steel sheet surface is not particularly limited, but for example, the following method is preferably used. That is, surface observation is performed using a surface observation apparatus such as an SEM (scanning electron microscope) at a magnification of, for example, about 100 to 5000 times, more preferably about 500 to 2000 times. If observation is performed at a very high magnification, it is difficult to obtain average information. Conversely, if observation is performed at a low magnification, it is difficult to observe a compound mainly composed of manganese phosphate. Observation is performed by such a method, and the coverage area ratio of the compound mainly composed of manganese phosphate may be calculated by visual observation or image processing. It is also suitable to confirm that the observed compound is a compound mainly composed of manganese phosphate by using EDX analysis (energy dispersive X-ray analysis) or the like as necessary. It is also possible to calculate the covering area ratio by mapping elements such as P, Mn, and O using an apparatus such as EPMA (electron beam probe microanalyzer) or AES (Auger electron spectroscopy). In addition, in order to obtain average information on the covering area ratio of the compound mainly composed of manganese phosphate on the steel plate surface, it is preferable to observe at least a region of at least 5 visual fields by the above method, more preferably It is only necessary to observe an area of 10 fields of view or more and set the average value as the coverage area ratio. In addition, as a site | part to observe, the typical site | part of the steel plate in which the normal process was performed should be observed, and the edge part of a steel strip, the defective part of a steel strip, etc. should not be observed.

本発明において、リン酸マンガンを主体とする化合物が、平均粒径が3μm以下の粒状化合物であればより好ましく、平均粒径が1μm以下の粒状化合物であればさらに好ましい。この理由は、被覆面積率が同じであっても、粒径が小さいほど粒状化合物の数が増大し、耐型かじり性においては粒状化合物がコロの作用を発現し、その数が多いほど潤滑効果が増大するためである。また、塗装後耐食性については、粒状化合物の数が増大するほど鋼板露出部のエッチング性が高まって化成処理反応が促進され、鋼板露出部に形成されるリン酸亜鉛結晶が緻密化する作用と、粒状のリン酸マンガンを主体とする化合物自体が電着塗膜との密着性を向上させる作用の両者の効果が発現するためである。平均粒径が3μm以下の粒状化合物であれば耐型かじり性、塗装後耐食性の向上効果が顕著となるため好ましく、平均粒径が1μm以下の粒状化合物であれば耐型かじり性、塗装後耐食性の向上効果がさらに顕著となるためより好ましい。なお、粒状化合物の平均粒径が小さくなっても、耐型かじり性、塗装後耐食性に何ら悪影響をおよぼさないため、平均粒径の下限値については限定されない。   In the present invention, the compound mainly composed of manganese phosphate is more preferably a granular compound having an average particle diameter of 3 μm or less, and more preferably a granular compound having an average particle diameter of 1 μm or less. The reason for this is that even if the covering area ratio is the same, the smaller the particle size, the greater the number of granular compounds, and in terms of mold galling resistance, the granular compounds exhibit the action of a roller. This is because of the increase. In addition, as for the corrosion resistance after coating, as the number of granular compounds increases, the etching property of the steel plate exposed portion increases and the chemical conversion reaction is promoted, and the action of the zinc phosphate crystals formed on the steel plate exposed portion becomes dense, This is because the compound itself mainly composed of granular manganese phosphate exhibits both effects of improving the adhesion with the electrodeposition coating film. A granular compound having an average particle size of 3 μm or less is preferable because the effect of improving mold galling resistance and post-coating corrosion resistance becomes remarkable, and a granular compound having an average particle size of 1 μm or less is preferable for galling resistance and post-coating corrosion resistance. This is more preferable because the improvement effect becomes more remarkable. Even if the average particle size of the granular compound is reduced, the lower limit of the average particle size is not limited because it does not adversely affect mold galling resistance and post-coating corrosion resistance.

本発明において、粒状化合物の粒状とは、必ずしも球状あるいはそれに近い形状に限定されるものではなく、例えば円柱、円錐、直方体、多面体、多角錐などの形状、あるいは燐片状などの形状のものも含むものとする。すなわち、個々の粒がそれぞれ分離、独立して不連続に鋼板表面に分布していることを、本発明においては、鋼板表面上に粒状化合物が被覆されている、と表現することとする。これらの粒状化合物は、その形状にかかわらず、それぞれが分離、独立して不連続に鋼板表面に分布していることにより、耐型かじり性に対しては、凝着抑制効果、油膜の保持効果に加えて、その形状にかかわらずコロの作用を発現するため、耐型かじり性をより一層向上させる。また、塗装後耐食性に対しても、その形状にかかわらず、粒状化合物の数が増大することにより、鋼板露出部のエッチング性を高めてリン酸亜鉛結晶を緻密化させる作用と、化合物自体が電着塗膜との密着性を向上させる作用の両者の効果を発揮することが可能である。   In the present invention, the granular form of the granular compound is not necessarily limited to a spherical shape or a shape close thereto. For example, a cylindrical shape, a cone shape, a rectangular parallelepiped shape, a polyhedron shape, a polygonal pyramid shape, or a flake shape shape is also possible. Shall be included. That is, in the present invention, it is expressed that the granular compound is coated on the surface of the steel sheet, in which the individual grains are separated and distributed independently and discontinuously on the surface of the steel sheet. Regardless of their shape, these granular compounds are separated and distributed independently and discontinuously on the surface of the steel sheet. In addition, since the action of the roller is exhibited regardless of its shape, the mold galling resistance is further improved. In addition, with respect to the corrosion resistance after coating, regardless of its shape, the number of granular compounds increases, thereby improving the etching properties of the exposed steel plate and densifying the zinc phosphate crystals. It is possible to exhibit both effects of improving the adhesion with the coating film.

本発明における前記粒状化合物の平均粒径の測定は、SEM(走査型電子顕微鏡)等の表面観察装置を用いて実施する。すなわち、SEM等により得られた2次元画像に表示された個々の粒状化合物を、それぞれ同じ面積の真円に置き換えてそれぞれの粒径を測定する。これらの粒径を平均することにより平均粒径の値とする。   The average particle size of the granular compound in the present invention is measured using a surface observation device such as SEM (scanning electron microscope). That is, each particle compound displayed in the two-dimensional image obtained by SEM or the like is replaced with a perfect circle having the same area, and each particle size is measured. The average particle diameter is obtained by averaging these particle diameters.

一方、本発明における非粒状化合物とは、上記の粒状化合物に該当しない形状のものを指す。すなわち、被覆面積率がたとえ2〜50%の範囲であったとしても、被覆されている化合物が分離、独立しておらず、その一部で連結してネットワークを構成しているような場合である。たとえば、網目状の形状や、あるいはその一部に空隙部を有する膜状の形状などが例示される。   On the other hand, the non-particulate compound in this invention refers to the thing of the shape which does not correspond to said granular compound. In other words, even if the covering area ratio is in the range of 2 to 50%, the covered compounds are not separated and independent, but are partly connected to form a network. is there. For example, a mesh-like shape or a film-like shape having a void portion in a part thereof is exemplified.

本発明の鋼板を製造する方法については、本発明の構成要件を満足する鋼板が製造可能な方法であれば何ら限定されず、反応型処理、電解型処理、浸漬型処理、塗布型処理などの方法が可能である。反応型処理としては、例えば、リン酸、リン酸マンガン、硝酸マンガンなど、リン酸イオンとマンガンイオンを含有する水溶液を使用して、これを鋼板にスプレーしたり、この水溶液に鋼板を浸漬したりする方法がある。また、この水溶液には必要に応じFeイオン、Niイオン、Coイオン、Mgイオンなどのカチオンや、硫酸イオン、亜硝酸イオン、フッ化物イオン等のアニオンを添加することも好適である。電解型処理としては、例えば前記反応型処理と同様の水溶液中で鋼板を陰極電解、陽極電解、交番電解する方法が例示される。浸漬型処理としては、例えばリン酸マンガン粒子を分散させた処理液中に鋼板を浸漬し、水洗することなく乾燥させる方法が例示される。処理液の安定性を確保するために、界面活性剤や有機添加剤等を適宜添加してもよい。塗布型処理としては、例えば前記浸漬型処理液と同様の処理液をロールコーター等を用いて鋼板に塗布し乾燥させる方法が例示される。なお、いずれの処理を行う場合にも、鋼板表面を洗浄または活性化するための前処理を実施してもよく、公知の酸やアルカリを用いた前処理がいずれも適用可能である。   The method for producing the steel sheet of the present invention is not limited as long as the steel sheet that satisfies the structural requirements of the present invention can be produced, such as reactive treatment, electrolytic treatment, immersion treatment, coating treatment, etc. A method is possible. As the reactive treatment, for example, an aqueous solution containing phosphate ions and manganese ions, such as phosphoric acid, manganese phosphate, and manganese nitrate, is sprayed on a steel plate, or the steel plate is immersed in this aqueous solution. There is a way to do it. In addition, it is also preferable to add cations such as Fe ions, Ni ions, Co ions, and Mg ions, and anions such as sulfate ions, nitrite ions, and fluoride ions to the aqueous solution as necessary. Examples of the electrolytic treatment include a method of cathodic electrolysis, anodic electrolysis, and alternating electrolysis of a steel sheet in an aqueous solution similar to the reactive treatment. Examples of the immersion type treatment include a method in which a steel sheet is immersed in a treatment liquid in which manganese phosphate particles are dispersed and dried without being washed with water. In order to ensure the stability of the treatment liquid, a surfactant, an organic additive, or the like may be added as appropriate. Examples of the coating type treatment include a method in which a treatment liquid similar to the immersion type treatment liquid is applied to a steel sheet using a roll coater or the like and dried. In any of the treatments, a pretreatment for cleaning or activating the steel plate surface may be performed, and any known pretreatment using an acid or alkali may be applied.

以下、本発明を実施例に基づきさらに詳細に説明する。   Hereinafter, the present invention will be described in more detail based on examples.

使用した供試鋼板を表1に示す。熱延鋼板としては引張強度が270MPa級、590MPa級、980MPa級の3種の鋼板を用い、いずれも酸洗処理により黒皮を除去した鋼板を用いた。また、冷延鋼板としては引張強度が270MPa級、590MPa級、980MPa級の焼鈍処理後の鋼板を用いた。なお、板厚はいずれも1.2mmの鋼板を用いた。   Table 1 shows the test steel plates used. As the hot-rolled steel plate, three types of steel plates having a tensile strength of 270 MPa class, 590 MPa class, and 980 MPa class were used, and steel sheets from which black skin was removed by pickling treatment were used. In addition, as the cold-rolled steel sheet, steel sheets after annealing with tensile strengths of 270 MPa class, 590 MPa class, and 980 MPa class were used. In addition, the plate thickness used the steel plate of 1.2 mm in all cases.

これらの鋼板に対し、リン酸マンガンを主体とする化合物を被覆する処理を行った。   These steel sheets were treated with a compound mainly composed of manganese phosphate.

反応型処理は2通りの方法で行った。反応型処理aは、市販のリン酸マンガン処理薬剤(日本パーカライジング株式会社製、パルホスM1Aシステム)を使用して、アルカリ脱脂、水洗、表面調整、リン酸マンガン処理の手順で行った。表面調整は、プレパレン55(日本パーカライジング株式会社製)を標準条件で建浴し、標準処理時間である30秒の浸漬処理により行った。リン酸マンガン処理時間については、標準条件が3〜15分であるのに対して、1〜120秒の短時間処理に変更して処理を行った。反応型処理bは、鋼板表面にMnが濃化している590MPa級冷延鋼板Eを原板として使用し、この鋼板にアルカリ脱脂および水洗処理を施した後、89%リン酸水溶液:2g/l、硝酸ナトリウム:10g/lからなる水溶液に浸漬して鋼板表面に濃化していたマンガン酸化物をリン酸マンガン主体の化合物に改質することにより行った。   The reactive process was performed in two ways. The reactive treatment a was carried out using a commercially available manganese phosphate treating agent (Nippon Parkerizing Co., Ltd., Parfos M1A system) in the order of alkali degreasing, water washing, surface adjustment, and manganese phosphate treatment. The surface adjustment was performed by immersing preparene 55 (manufactured by Nihon Parkerizing Co., Ltd.) under standard conditions and dipping for 30 seconds, which is a standard treatment time. The manganese phosphate treatment time was changed to a short-time treatment of 1 to 120 seconds, while the standard condition was 3 to 15 minutes. In the reactive treatment b, a 590 MPa class cold-rolled steel sheet E having Mn concentrated on the steel sheet surface was used as an original sheet, and the steel sheet was subjected to alkali degreasing and water washing treatment, and then 89% phosphoric acid aqueous solution: 2 g / l, Sodium nitrate: This was performed by modifying manganese oxide concentrated on the steel sheet surface by immersion in an aqueous solution of 10 g / l into a compound mainly composed of manganese phosphate.

電解型処理は、89%リン酸水溶液:2g/l、硝酸ナトリウム:10g/l、硝酸マンガン:10g/lからなる処理液を用い、鋼板を陰極として電流密度1〜5A/dmで10秒間電解することによりサンプルを作製した。浸漬型処理は、種々の平均粒径のリン酸マンガン粒子を分散させた処理液中に鋼板を5秒間浸漬させ、水洗することなく乾燥することによりサンプルを作製した。なお、処理液の安定性を確保するため有機系の界面活性剤を処理液に添加した。塗布型処理は上記浸漬型処理と同じ処理液を用い、ロールコーターにより鋼板に処理液を塗布し、水洗することなく乾燥することによりサンプルを作製した。なお、電解型処理、浸漬型処理、塗布型処理のいずれも、アルカリ脱脂により表面を清浄化した鋼板に対して上記の処理を施した。 The electrolytic treatment uses a treatment solution consisting of 89% phosphoric acid aqueous solution: 2 g / l, sodium nitrate: 10 g / l, manganese nitrate: 10 g / l, using a steel plate as a cathode at a current density of 1 to 5 A / dm 2 for 10 seconds. A sample was prepared by electrolysis. In the immersion type treatment, a sample was prepared by immersing a steel plate in a treatment solution in which manganese phosphate particles having various average particle diameters were dispersed for 5 seconds and drying without washing with water. In addition, in order to ensure the stability of the treatment liquid, an organic surfactant was added to the treatment liquid. The coating type treatment used the same processing liquid as the above immersion type processing, applied the processing liquid to the steel sheet with a roll coater, and dried the sample without washing with water. In addition, in any of the electrolytic treatment, the immersion treatment, and the coating treatment, the above-described treatment was performed on the steel plate whose surface was cleaned by alkali degreasing.

リン酸マンガンを主体とする化合物の付着量は、化合物を溶解する前後の重量差から求める重量法、または溶解液中のMnイオンやPOイオン濃度から求める湿式分析法により算出した。 The adhesion amount of the compound mainly composed of manganese phosphate was calculated by a weight method obtained from a weight difference before and after the compound was dissolved, or a wet analysis method obtained from the Mn ion and PO 4 ion concentration in the solution.

リン酸マンガンを主体とする化合物の被覆面積率の算出はSEM観察により行い、倍率を750倍として10視野の観察を行い、目視で算出した被覆面積率の平均値をその鋼板の被覆面積率とした。また、SEM観察により化合物の形状が粒状であるか非粒状であるかを判断し、粒状である場合にはその平均粒径をSEM写真から算出した。   Calculation of the covering area ratio of the compound mainly composed of manganese phosphate is performed by SEM observation, observation is performed for 10 fields of view at a magnification of 750 times, and the average value of the covering area ratio calculated visually is the covering area ratio of the steel sheet. did. Moreover, it was judged by SEM observation whether the shape of the compound was granular or non-granular, and when it was granular, the average particle diameter was calculated from the SEM photograph.

耐型かじり性の評価は摺動試験機を用いて行い、金型の押付け荷重を100MPaから50MPa刻みで上昇させながら鋼板に摺動を加え、目視観察により鋼板に型かじりが生じていなかった最大荷重の値である限界耐荷重を求めることにより評価した。なお、摺動試験を行う際の金型は、材質がSKD11、金型の幅が10mm、金型と鋼板との摺動方向の接触長が3mmで、摺動方向の金型端部には4.5mmのRを付与した形状のものを用いた。また摺動条件は、摺動速度1.0m/min、摺動距離100mmとし、一般防錆油(出光興産株式会社製、ダフニーオイルコートSK)を塗油した鋼板に対して摺動試験を行った。この試験により、耐型かじり性を以下の基準に従い判定した。
◎:限界耐荷重が1000MPa以上
○:限界耐荷重が500MPa以上、1000MPa未満
△:限界耐荷重が300MPa以上、500MPa未満
×:限界耐荷重が300MPa未満
The evaluation of mold galling resistance was carried out using a sliding tester, the steel sheet was slid while raising the pressing load of the mold in increments of 100 MPa to 50 MPa, and no galling occurred on the steel sheet by visual observation. Evaluation was made by obtaining a limit load capacity which is a load value. The mold used for the sliding test is made of SKD11, the width of the mold is 10 mm, the contact length in the sliding direction between the mold and the steel plate is 3 mm, and the end of the mold in the sliding direction is The shape which gave R of 4.5 mm was used. The sliding conditions were a sliding speed of 1.0 m / min, a sliding distance of 100 mm, and a sliding test was performed on a steel plate coated with general rust preventive oil (Idemitsu Kosan Co., Ltd., Daphne Oil Coat SK). It was. By this test, mold galling resistance was determined according to the following criteria.
◎: Limit load capacity is 1000 MPa or more ○: Limit load resistance is 500 MPa or more and less than 1000 MPa Δ: Limit load resistance is 300 MPa or more and less than 500 MPa ×: Limit load resistance is less than 300 MPa

塗装後耐食性の評価は、化成処理後に電着塗装を施した鋼板を塩温水浸漬試験に供し、クロスカット部での片側最大剥離幅を測定することにより行った。ここで、化成処理は日本パーカライジング株式会社製のパルボンドPB−L3020システムを標準条件で行い、電着塗装は関西ペイント株式会社製のGT−10LFを用い、膜厚20μm、焼付け条件175℃×25分の条件でサンプルを作製した。このサンプルにクロスカットを入れ、液温55℃の5%塩化ナトリウム水溶液中に240時間浸漬し、引き上げ乾燥後、クロスカット部をセロハン粘着テープにより剥離して片側最大剥離幅を測定した。この試験により、塗装後耐食性を以下の基準に従い判定した。
◎:片側最大剥離幅が2.0mm未満
○:片側最大剥離幅が2.0mm以上2.5mm未満
△:片側最大剥離幅が2.5mm以上3.0mm未満
×:片側最大剥離幅が3.0mm以上
Evaluation of the corrosion resistance after coating was performed by subjecting the steel sheet electrodeposited after the chemical conversion treatment to a salt warm water immersion test and measuring the maximum peel width on one side at the crosscut part. Here, the chemical conversion treatment is performed using Palbond PB-L3020 system manufactured by Nihon Parkerizing Co., Ltd. under standard conditions, and electrodeposition coating is performed using GT-10LF manufactured by Kansai Paint Co., Ltd. Samples were prepared under the conditions described above. A cross cut was put into this sample, immersed in a 5% sodium chloride aqueous solution at a liquid temperature of 55 ° C. for 240 hours, pulled up and dried, and then the cross cut portion was peeled off with a cellophane adhesive tape, and the maximum peel width on one side was measured. By this test, the corrosion resistance after coating was determined according to the following criteria.
A: One-side maximum peel width is less than 2.0 mm. O: One-side maximum peel width is 2.0 mm or more and less than 2.5 mm. Δ: One-side maximum peel width is 2.5 mm or more and less than 3.0 mm. 0mm or more

表2に、使用した鋼板、処理方法、リン酸マンガンを主体とする化合物の付着量、被覆面積率、形状と平均粒径、ならびに耐型かじり性と塗装後耐食性の評価結果を示す。   Table 2 shows the evaluation results of the steel plate used, the treatment method, the adhesion amount of the compound mainly composed of manganese phosphate, the covering area ratio, the shape and the average particle diameter, and the anti-galling property and the corrosion resistance after coating.

Figure 2006299350
Figure 2006299350

Figure 2006299350
Figure 2006299350

表2に示すように、本発明の鋼板はいずれも耐型かじり性、塗装後耐食性に優れる。   As shown in Table 2, all of the steel plates of the present invention are excellent in mold galling resistance and post-coating corrosion resistance.

本発明の鋼板は、自動車分野等の用途分野で使用される耐型かじり性および塗装後耐食性に優れる冷延鋼板または熱延鋼板として利用することができる。さらに、本発明の鋼板は、自動車分野等の用途分野で使用される耐型かじり性および塗装後耐食性に優れる高強度鋼板(高強度熱延鋼板または高強度冷延鋼板)として利用することができる。   The steel sheet of the present invention can be used as a cold-rolled steel sheet or a hot-rolled steel sheet excellent in mold galling resistance and post-coating corrosion resistance used in application fields such as the automobile field. Furthermore, the steel sheet of the present invention can be used as a high-strength steel sheet (high-strength hot-rolled steel sheet or high-strength cold-rolled steel sheet) excellent in mold galling resistance and post-coating corrosion resistance used in application fields such as the automobile field. .

Claims (2)

鋼板表面上にリン酸マンガンを主体とする化合物が2〜50%の面積率で被覆されていることを特徴とする耐型かじり性および塗装後耐食性に優れた鋼板。   A steel sheet excellent in mold galling resistance and post-coating corrosion resistance, characterized in that a compound mainly composed of manganese phosphate is coated on the steel sheet surface at an area ratio of 2 to 50%. リン酸マンガンを主体とする化合物が、平均粒径が3μm以下の粒状化合物であることを特徴とする請求項1記載の耐型かじり性および塗装後耐食性に優れた鋼板。   The steel sheet excellent in mold galling resistance and post-coating corrosion resistance according to claim 1, wherein the compound mainly composed of manganese phosphate is a granular compound having an average particle diameter of 3 µm or less.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009280845A (en) * 2008-05-20 2009-12-03 Nissan Motor Co Ltd Treatment method for metal surface, and sliding component having metal surface by the treatment method
US9470044B1 (en) 2015-07-06 2016-10-18 Pegasis S.r.l. Threaded connection having high galling resistance and method of making same

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009280845A (en) * 2008-05-20 2009-12-03 Nissan Motor Co Ltd Treatment method for metal surface, and sliding component having metal surface by the treatment method
US9470044B1 (en) 2015-07-06 2016-10-18 Pegasis S.r.l. Threaded connection having high galling resistance and method of making same
US10246948B2 (en) 2015-07-06 2019-04-02 Pegasus S.R.L. Threaded connection having high galling resistance and method of making same

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