JP3458762B2 - High-strength steel with excellent shore weather resistance - Google Patents
High-strength steel with excellent shore weather resistanceInfo
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- JP3458762B2 JP3458762B2 JP11630799A JP11630799A JP3458762B2 JP 3458762 B2 JP3458762 B2 JP 3458762B2 JP 11630799 A JP11630799 A JP 11630799A JP 11630799 A JP11630799 A JP 11630799A JP 3458762 B2 JP3458762 B2 JP 3458762B2
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Description
【0001】[0001]
【発明の属する技術分野】本発明は、建築・土木分野に
おける各種構造物に用いる摩擦接合用の高力ボルト・ナ
ットの製造に適した鋼に関し、特に海岸地域の構造物な
ど塩水が関与した腐食環境で用いられる海岸耐候性に優
れた高力ボルト・ナットの製造に適した鋼に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to steel suitable for manufacturing high-strength bolts and nuts for friction welding used in various structures in the field of construction and civil engineering, and particularly to corrosion caused by salt water such as structures in coastal areas. The present invention relates to steel suitable for manufacturing high-strength bolts and nuts with excellent coastal weather resistance used in the environment.
【0002】[0002]
【従来の技術】従来鋼構造物を無塗装のままで使用する
場合、耐候性鋼を用いることが知られており、既に鋼板
や形鋼に関してはJIS G3114「溶接構造用耐候
性熱間圧延鋼材」やJIS G3125「高耐候性圧延
鋼材」に規格化されている。しかしそれらの鋼構造物の
継手に用いられる高力ボルトに関しては国内で何ら規格
化されていない。2. Description of the Related Art Conventionally, when a steel structure is used without being coated, it is known to use weather-resistant steel. Regarding steel plates and shaped steels, JIS G3114 "Weather-resistant hot-rolled steel for welded structure" has already been used. ] And JIS G3125 “High weather resistance rolled steel”. However, there is no standardization in Japan for high-strength bolts used for joints of those steel structures.
【0003】高力ボルトは、その目的から、鋼板や形鋼
と異なり、極めて高強度を必要とするため、焼入れ焼戻
し処理が施される。従って上記規格の鋼をそのまま高力
ボルト用素材として利用することは不可能である。この
ような問題を解決する技術として、これまでに特公昭5
3−24890号公報および特公昭56−20350号
公報が開示されている。High-strength bolts require extremely high strength, unlike steel plates and shaped steels, for the purpose thereof, and are therefore subjected to quenching and tempering treatment. Therefore, it is impossible to use the steel of the above standard as it is as a material for high strength bolts. As a technology for solving such problems, Japanese Patent Publication No.
JP-A-3-24890 and JP-B-56-20350 are disclosed.
【0004】これらはいずれも最終的に焼入れ焼戻し処
理を施され1000MPa以上の強度で用いることを前
提としている。特公昭53−24890号公報はCu,
Cr,Siの添加で耐候性を確保すると同時に、Si,
Al添加の効果で、高強度鋼に特有の遅れ破壊を抑制し
たことが特徴である。また特公昭56−20350号公
報はCu,Crの添加で耐候性を確保したうえで、Si
を低減してボルト冷間成型前の焼鈍省略を可能としたも
のである。All of these are premised on the fact that they are finally subjected to quenching and tempering treatment and have a strength of 1000 MPa or more. JP-B-53-24890 is Cu,
At the same time as securing the weather resistance by adding Cr, Si,
The feature is that delayed fracture peculiar to high strength steel is suppressed by the effect of adding Al. Further, Japanese Patent Publication No. 56-20350 discloses that Si and Si are added after securing the weather resistance by adding Cu and Cr.
It is possible to omit annealing before bolt cold forming by reducing the above.
【0005】このような耐候性鋼は、大気暴露環境にお
いて、Cu,Crなどの有効元素が富化した防食性の高
い安定錆が表面を覆うことにより、著しく腐食の進展が
遅延されるというものである。その著しく良好な耐候性
のため、耐候性を利用した鋼構造物は、しばしば無塗装
のまま数十年の供用に耐えることが知られている。しか
し、海岸地域のように塩分が比較的多い環境(飛来塩分
量0.05mdd以上)では、耐候性鋼の錆は安定化し
にくく、実用的な耐食性が得難いことが知られている。
こうした環境で実用に耐えうる鋼材を提供する技術とし
て、特開平7−207340号公報や特開平7−242
993号公報が開示されている。In such weather resistant steel, stable corrosion-resistant rust enriched with effective elements such as Cu and Cr covers the surface of the weather-resistant steel, whereby the progress of corrosion is significantly delayed. Is. Due to its remarkably good weather resistance, steel structures utilizing weather resistance are often known to survive decades of service unpainted. However, it is known that in an environment where the salt content is relatively high (flying salt content of 0.05 mdd or more) such as in the coastal area, the rust of the weather resistant steel is difficult to stabilize and it is difficult to obtain practical corrosion resistance.
As a technique for providing a steel material that can be practically used in such an environment, JP-A-7-207340 and JP-A-7-242 are known.
Japanese Patent No. 993 is disclosed.
【0006】[0006]
【発明が解決しようとする課題】しかしながら、特開平
7−207340号公報や特開平7−242993号公
報に開示されている技術はいずれも鋼板を対象としたも
のであり、上述のように高力ボルト・ナット向けの素材
として利用することは不可能である。However, the techniques disclosed in Japanese Patent Application Laid-Open Nos. 7-207340 and 7-242993 are all directed to steel plates and have high strength as described above. It cannot be used as a material for bolts and nuts.
【0007】以上のように、従来の技術によっては、飛
来塩分量0.05mdd以上の地域において実用的な耐
候性を有する鋼で、高力ボルトの製造においては冷間鍛
造前の焼鈍省略が可能で、かつ上述した耐候性を有する
ナットを製造することができなかった。As described above, according to the conventional technique, steel having practical weather resistance in a region having a flying salt content of 0.05 mdd or more can be omitted in the production of high strength bolts before annealing for cold forging. In addition, it was not possible to manufacture the above-mentioned weather resistant nut.
【0008】本発明の目的は、このような問題点を解決
するために、塩分、特に0.05mdd以上の塩分が飛
来する環境において高い耐候性を有し、かつ熱間圧延後
硬さがHRB85以下である、焼入れ焼戻し後引張強
さ:980MPa以上の焼鈍省略型高力ボルトおよびナ
ットの製造に適した鋼を提供することにある。In order to solve such a problem, an object of the present invention is to have high weather resistance in an environment where salt content, particularly salt content of 0.05 mdd or more comes in, and the hardness after hot rolling is HRB85. The purpose of the present invention is to provide a steel suitable for manufacturing a high-strength bolt and nut that does not need annealing and has the following tensile strength after quenching and tempering: 980 MPa or more.
【0009】[0009]
【課題を解決するための手段】前記課題を解決し目的を
達成するために、本発明は以下に示す手段を用いてい
る。In order to solve the above problems and achieve the object, the present invention uses the following means.
【0010】(1)本発明の鋼は、質量%で、C:0.
15〜0.3%と、Si:0.15%以下と、Mn:
0.3〜0.6%と、P:0.01%以下と、S:0.
01%以下と、Al:0.01〜0.05%と、N:
0.002〜0.01%と、Ni:1〜2%と、Mo:
0.1〜0.3%と、Ti:0.01〜0.05%と、
B:0.0003〜0.005%と、残部Fe及び不可
避的不純物とからなる、海岸耐候性に優れた高強度鋼で
ある。[0010] (1) the steel of the present invention, in mass%, C: 0.
15-0.3%, Si: 0.15% or less, Mn:
0.3-0.6%, P: 0.01% or less, S: 0.
01% or less, Al: 0.01 to 0.05%, N:
0.002-0.01%, Ni: 1-2%, Mo:
0.1 to 0.3%, Ti: 0.01 to 0.05%,
B: 0.0003 to 0.005%, balance Fe and improper
It is a high-strength steel with excellent weather resistance that is composed of evasive impurities .
【0011】(2)本発明の鋼は、鋼成分として、質量
%でさらに、Cu:0.1〜0.5%、Cr:0.3〜
1%のうちの一種または二種を含有する、上記(1)に
記載の海岸耐候性に優れた高強度鋼である。
(3)本発明のボルトは上記(1)又は(2)の鋼成分
を有する。
(4)本発明のナットは上記(1)又は(2)の鋼成分
を有する。(2) The steel of the present invention has a mass of
% , Further Cu: 0.1 to 0.5%, Cr: 0.3 to
The high-strength steel containing 1% or 2% of 1% and excellent in coastal weather resistance according to the above (1). (3) The bolt of the present invention has the steel component as described in (1) or (2) above. ( 4 ) The nut of the present invention has the steel component described in (1) or (2) above.
【0012】[0012]
【発明の実施の形態】本発明者らは上記課題の達成のた
めに、引張強さ:980MPa以上の強度を確保するこ
とを前提として、鋼材の化学成分と耐候性および熱間圧
延後硬さとの関係について鋭意検討を行った結果、次の
知見を得るに至った。BEST MODE FOR CARRYING OUT THE INVENTION In order to achieve the above object, the present inventors assume that a tensile strength of 980 MPa or more is secured, and the chemical composition and weather resistance of the steel material and the hardness after hot rolling are As a result of diligent examination of the relationship, the following findings were obtained.
【0013】(1)飛来塩分量0.05mdd以上の環
境で優れた耐候性を得るためには、NiおよびMoの複
合添加が有効である。(1) In order to obtain excellent weather resistance in an environment with a flying salt content of 0.05 mdd or more, the combined addition of Ni and Mo is effective.
【0014】(2)Pは飛来塩分量0.05mdd以上
の環境で優れた耐候性を得るのに有効であるが、高力ボ
ルトにおいては遅れ破壊を助長する悪影響が顕著なた
め、その添加量を抑制する必要がある。しかしPを低減
することによる耐食性の低下は、Niの増量で十分に補
うことができる。(2) P is effective for obtaining excellent weather resistance in an environment with a flying salt content of 0.05 mdd or more, but in high strength bolts, the adverse effect of promoting delayed fracture is remarkable, so the addition amount thereof is Need to be suppressed. However, the decrease in corrosion resistance caused by reducing P can be sufficiently compensated by increasing the amount of Ni.
【0015】(3)NiおよびMo添加の一方で、Si
およびMn添加量を低減することによって、熱間圧延後
のHRB硬さを85以下に抑えることができる。(3) While adding Ni and Mo, Si
By reducing the amount of addition of Mn and Mn, the HRB hardness after hot rolling can be suppressed to 85 or less.
【0016】以上の知見に基づき、本発明者らは、0.
05mdd以上の塩分が飛来する環境において耐候性向
上のためNi,Moを一定量複合添加し、耐遅れ破壊の
ためP量を低減し、さらに高力ボルトの製造において冷
間鍛造前の焼鈍省略のためSi,Mn添加量を低減した
高強度鋼を見出し、本発明を完成させた。Based on the above findings, the present inventors have found that
In an environment where a salt content of 05 mdd or more comes in, a fixed amount of Ni and Mo are added in combination to improve weather resistance, the amount of P is reduced for delayed fracture resistance, and in the production of high strength bolts, annealing before cold forging can be omitted. Therefore, the inventors have found a high-strength steel in which the amounts of Si and Mn added are reduced, and completed the present invention.
【0017】すなわち、本発明は、鋼組成を下記範囲に
限定することにより、塩分、特に0.05mdd以上の
塩分が飛来する環境において高い耐候性を有し、高力ボ
ルトの製造においては熱間圧延後硬さがHRB:85以
下で、冷間鍛造前の焼鈍省略が可能でその後の焼入れ焼
戻し後引張強さ:980MPa以上となる高力ボルトの
製造に適し、ナットの製造においては上述した耐候性を
有するナットの製造に適した高強度鋼を提供することが
できる。That is, according to the present invention, by limiting the steel composition to the following range, it has high weather resistance in an environment in which salt, particularly 0.05 mdd or more of salt comes in, and in the production of high strength bolts Hardness after rolling is HRB: 85 or less, annealing before cold forging can be omitted, and subsequent tensile strength after quenching and tempering: suitable for manufacturing high strength bolts of 980 MPa or more. It is possible to provide a high-strength steel suitable for manufacturing a nut having properties.
【0018】以下に、本発明の成分添加理由、及び成分
限定理由について説明する。The reasons for adding the components of the present invention and the reasons for limiting the components will be described below.
【0019】(1)成分組成範囲
C:0.15〜0.3%
Cは焼入れ焼戻し処理により引張強さを確保するために
必要な元素である。0.15%未満では必要な引張強さ
が得られず、0.3%を越えるとボルト成型加工時の変
形抵抗が増大して加工性が低下するため、その含有量は
0.15〜0.3%である。(1) Component composition range C: 0.15 to 0.3% C is an element necessary for securing tensile strength by quenching and tempering. If it is less than 0.15%, the required tensile strength cannot be obtained, and if it exceeds 0.3%, the deformation resistance at the time of bolt forming increases and the workability decreases, so the content is 0.15 to 0. It is 0.3%.
【0020】Si:0.15%以下
Siは脱酸剤として必要であるが0.15%越えとなる
と熱間圧延後の硬さが増大するため、その含有量は0.
15%以下である。Si: 0.15% or less Si is necessary as a deoxidizing agent, but if it exceeds 0.15%, the hardness after hot rolling increases, so its content is 0.
It is 15% or less.
【0021】Mn:0.3〜0.6%
MnはSを固定するために添加するが、0.3%未満で
は熱間圧延時にMnSの固溶再析出が生じて延性が低下
する。また0.6%を越えると焼入れ性が高くなり、熱
間圧延後の硬さが上昇するため、その含有量は0.3〜
0.6%である。 P:0.01%以下
Pは優れた耐候性を得るのに有効であるが、0.01%
を越えると靭性が劣化するため、その含有量は0.01
%以下である。Mn: 0.3 to 0.6% Mn is added to fix S, but if it is less than 0.3%, solid solution reprecipitation of MnS occurs during hot rolling, and ductility decreases. Further, if it exceeds 0.6%, the hardenability becomes high, and the hardness after hot rolling increases, so the content is 0.3-.
It is 0.6%. P: 0.01% or less P is effective for obtaining excellent weather resistance, but 0.01%
When the content exceeds 0.01, the toughness deteriorates, so the content is 0.01.
% Or less.
【0022】S:0.01%以下
Sは鋼中でMnSとして存在するが、0.01%を越え
るとMnS量が多くなって靭性が劣化するため、その含
有量は0.01%以下である。S: 0.01% or less S exists as MnS in steel, but if it exceeds 0.01%, the MnS amount increases and the toughness deteriorates. Therefore, the content is 0.01% or less. is there.
【0023】Al:0.01〜0.05%
Alは脱酸剤として添加されるだけでなく、AlNとし
て析出することにより組織を微細化して靭性を向上させ
るため、その添加量は0.01%以上である。しかし
0.05%を越えると酸化物系の介在物が多くなりかえ
って靭性が劣化するため、その含有量は0.01〜0.
05%である。Al: 0.01-0.05% Al is not only added as a deoxidizing agent, but also precipitates as AlN to refine the structure and improve toughness, so the addition amount is 0.01. % Or more. However, if it exceeds 0.05%, the amount of oxide-based inclusions increases and the toughness deteriorates. Therefore, the content is 0.01 to 0.
It is 05%.
【0024】N:0.002〜0.01%
NはAlNとして析出することにより組織を微細化して
靭性を向上させるため、その添加量は0.002%以上
である。しかし0.01%を越えると固溶Nによって靭
性が劣化するため、その含有量は0.002〜0.01
%である。N: 0.002-0.01% N precipitates as AlN to refine the structure and improve toughness, so the addition amount is 0.002% or more. However, if it exceeds 0.01%, the solid solution N deteriorates the toughness, so the content is 0.002-0.01.
%.
【0025】Ni:1〜2%
Niは本発明において重要な元素であり、Moとの複合
添加で0.05mdd以上の塩分が飛来する環境におい
て耐候性を大幅に改善する効果を有する。1%未満では
その効果が得られず、2%を越えると焼入れ性が高くな
り、熱間圧延後の硬さが上昇するため、その含有量は1
〜2%である。Ni: 1 to 2% Ni is an important element in the present invention, and when added together with Mo, it has the effect of significantly improving the weather resistance in an environment where a salt content of 0.05 mdd or more comes in. If it is less than 1%, the effect cannot be obtained, and if it exceeds 2%, the hardenability becomes high and the hardness after hot rolling increases, so the content is 1
~ 2%.
【0026】Mo:0.1〜0.3%
Moは本発明において重要な元素であり、Niとの複合
添加で0.05mdd以上の塩分が飛来する環境におい
て耐候性を大幅に改善する効果を有する。0.1%未満
ではその効果が得られず、0.3%を越えると焼入れ性
が高くなり、熱間圧延後の硬さが上昇するため、その含
有量は0.1〜0.3%である。Mo: 0.1 to 0.3% Mo is an important element in the present invention, and when added together with Ni, it has the effect of significantly improving the weather resistance in an environment where a salt content of 0.05 mdd or more comes in. Have. If it is less than 0.1%, the effect cannot be obtained, and if it exceeds 0.3%, the hardenability becomes high and the hardness after hot rolling increases, so the content is 0.1 to 0.3%. Is.
【0027】Ti:0. 01〜0.05%
TiはNを固定することにより、Bの窒化物としての析
出を抑え、焼入れ性に対して有効に作用する効果を有す
る。0.01%以上で効果を有するが、0.05%を越
えると効果が飽和するため、その含有量は0.01〜
0.05%である。 B:0.0003〜0.005%
Bは焼入れ性を高める効果があるが、0.0003%未
満ではその効果が得られず、0.005%を越えると効
果が飽和するため、その含有量は0.0003〜0.0
05%である。Ti: 0.01-0.05% Ti fixes N to prevent precipitation of B as a nitride and has an effect of effectively acting on hardenability. When the content is 0.01% or more, the effect is obtained, but when the content is more than 0.05%, the effect is saturated.
It is 0.05%. B: 0.0003 to 0.005% B has the effect of enhancing hardenability, but if it is less than 0.0003%, the effect cannot be obtained, and if it exceeds 0.005%, the effect is saturated, so the content thereof is Is 0.0003 to 0.0
It is 05%.
【0028】本発明では、上記化学成分の他に、Cu,
Crの一種または二種を適宜添加することができる。In the present invention, in addition to the above chemical components, Cu,
One or two kinds of Cr can be added appropriately.
【0029】これら化学成分の限定理由について説明す
る。The reasons for limiting these chemical components will be described.
【0030】Cu:0.1〜0.5%
Cuは、NiやMoと同様、耐候性を向上させるのに有
効な元素であるが、その含有量が0.1%未満では効果
がなく、0.5%をこえると加工性が低下するため、そ
の添加量は0.1〜0.5%である。Cu: 0.1 to 0.5% Like Ni and Mo, Cu is an element effective for improving the weather resistance, but if the content is less than 0.1%, it has no effect. If it exceeds 0.5%, the workability is deteriorated, so the addition amount is 0.1 to 0.5%.
【0031】Cr:0.3〜1%
CrはNiやMoと同様、耐候性を向上させるのに有効
な元素であるが、その含有量が0.3%未満では効果が
なく、1%を越えると熱間圧延後の硬さが上昇するた
め、その添加量は0.3〜1%である。Cr: 0.3 to 1% Cr, like Ni and Mo, is an element effective for improving weather resistance, but if the content of Cr is less than 0.3%, there is no effect and 1% is added. If it exceeds, the hardness after hot rolling increases, so the addition amount is 0.3 to 1%.
【0032】なお、高力ボルトは上記の化学成分の鋼を
溶製し、熱間圧延により丸棒にされた後、冷間でボルト
成形・ネジ転造され、焼入れ焼戻し処理をされて製造さ
れる。ナットはボルトと同一の化学成分の鋼を熱間圧延
により丸棒にしたものを素材とし、熱間鍛造で成形、そ
のまま鍛造焼き入れされ、引き続き焼戻し処理されて製
造される。ボルト施工に際しては、座金もボルト・ナッ
トと共金にすることが望ましい。以下に本発明の実施例
を挙げ、本発明の効果を立証する。The high-strength bolt is manufactured by melting the steel having the above-mentioned chemical composition, making it into a round bar by hot rolling, cold-forming the bolt, thread-rolling it, and quenching and tempering it. It The nut is manufactured by forming a round bar by hot rolling steel having the same chemical composition as the bolt, forming it by hot forging, forging and quenching as it is, and subsequently tempering it. When installing bolts, it is desirable to use washers that are the same as the bolts and nuts. Examples of the present invention will be given below to prove the effects of the present invention.
【0033】[0033]
【実施例】以下、本発明の実施例について説明する。表
1に示す化学成分を有する鋼(No.1〜9:本発明
鋼、No.10〜15:比較鋼)を溶製し、熱間圧延に
より22mmφの丸棒にした。この丸棒の断面のHRB
硬さを1/4d位置で5点測定し、その平均値を求めた
結果を併せて表1に示す。EXAMPLES Examples of the present invention will be described below. Steel having the chemical composition shown in Table 1 (No. 1 to 9: Inventive steel, No. 10 to 15: Comparative steel) was melted and hot rolled into a 22 mmφ round bar. HRB of the cross section of this round bar
The hardness is measured at 5 points at 1 / 4d position, and the average value is shown in Table 1.
【0034】本発明鋼No.1〜9はいずれもHRB硬
さが85未満であり、冷間鍛造前の焼鈍が不要であるの
に対し、比較鋼No.10、11、13、15はそれぞ
れC、Mn、Ni、Mo添加量が多いために熱間圧延後
の硬さが増加しており、焼鈍なしでは冷間鍛造ができな
い状況であった。比較鋼No.12および14について
はHRB硬さは85未満であった。Inventive Steel No. In all of Examples 1 to 9, the HRB hardness is less than 85, and the annealing before cold forging is unnecessary, while the comparative steel No. Since Nos. 10, 11, 13, and 15 each contained a large amount of C, Mn, Ni, and Mo, the hardness after hot rolling increased, and cold forging could not be performed without annealing. Comparative steel No. For 12 and 14, the HRB hardness was less than 85.
【0035】上記丸棒を素材としてボルト成形を行っ
た。比較鋼No.10、11、13、15については軟
化焼鈍の後冷間鍛造で、それ以外については直接冷間鍛
造で(焼鈍無しで)行った。ボルト成形後、850℃か
ら1000℃の温度に加熱して焼入れを行い、その後1
030〜1130MPa級の引張強さになるよう焼戻し
処理をおこなった。ナットについては、ボルトと同一の
化学成分(表1)を有する鋼を熱間圧延により28mm
径の丸棒にしたあと、熱間鍛造でナットに成形してその
まま焼入れ、HRC25〜30の硬さが得られるよう焼
戻し処理を行った。Bolts were formed using the above round bar as a raw material. Comparative steel No. For 10, 11, 13, and 15, cold forging was performed after softening annealing, and for others, direct cold forging (without annealing) was performed. After the bolt is formed, it is heated to a temperature of 850 ° C to 1000 ° C for quenching, then 1
The tempering treatment was performed so that the tensile strength was in the range of 030 to 1130 MPa. For the nut, steel with the same chemical composition (Table 1) as the bolt was hot rolled to 28 mm
After forming a round bar having a diameter, it was formed into a nut by hot forging, quenched as it was, and tempered so that a hardness of HRC 25 to 30 was obtained.
【0036】以上のようにして得られたボルトとナット
を暴露腐食試験に供した。締め付けはボルト耐力の85
%の軸力で行った。施工の際、ボルト・ナット・座金す
べて共金とした。暴露腐食試験地は銚子で、試験期間は
1年間、飛来する塩分量はおよそ0.25mddであ
る。1年間の暴露の後、各供試鋼からなるボルトとナッ
トそれぞれの最大孔あき腐食深さを測定した。The bolts and nuts obtained as described above were subjected to an exposure corrosion test. Tighten bolt strength of 85
% Axial force was used. All bolts, nuts and washers were made of gold during the construction. The exposure corrosion test site is Choshi, the test period is one year, and the amount of salt coming in is about 0.25 mdd. After one year of exposure, the maximum perforated corrosion depth of each bolt and nut made of each sample steel was measured.
【0037】最大孔あき腐食深さ(ボルトとナットそれ
ぞれの最大孔あき腐食深さでより大きな孔あき腐食深
さ)の測定結果を併せて表1に示す。本発明鋼No.1
〜9はいずれも最大孔あき腐食深さが0.4mm未満で
あり、厳しい暴露条件のもとでも良好な耐候性を示すこ
とがわかる。Table 1 also shows the measurement results of the maximum pitting corrosion depth (larger pitting corrosion depth at the maximum pitting corrosion depth of each of the bolt and the nut). Invention Steel No. 1
It can be seen that all of Nos. 9 to 9 have a maximum pitting corrosion depth of less than 0.4 mm and exhibit good weather resistance even under severe exposure conditions.
【0038】一方、比較鋼No.12および14はそれ
ぞれそれぞれNi、Moが少ないために、耐候性が劣化
している。比較鋼No.10、11、13、15は本発
明鋼と同等の耐候性を示した。On the other hand, comparative steel No. Nos. 12 and 14, respectively, had a small amount of Ni and Mo, respectively, and thus had poor weather resistance. Comparative steel No. Nos. 10, 11, 13, and 15 showed weather resistance equivalent to that of the steels of the present invention.
【0039】[0039]
【表1】 [Table 1]
【0040】[0040]
【発明の効果】以上に示したように、本発明によれば、
鋼組成を特定することにより、0.05mdd以上の塩
分が飛来する環境において高い耐候性を有し、かつ高力
ボルトの製造においては熱間圧延後硬さがHRB:85
以下であり、冷間鍛造前の焼鈍が不要で、さらに、上述
した耐候性を有するナットの製造も可能な高強度鋼を提
供することができる。As described above, according to the present invention,
By specifying the steel composition, it has high weather resistance in the environment where salt content of 0.05 mdd or more comes in, and in the production of high strength bolts, the hardness after hot rolling is HRB: 85.
It is the following, and it is possible to provide high-strength steel that does not require annealing before cold forging and that can also manufacture the above-described nut having weather resistance.
【0041】本発明鋼からなる高力ボルトは、飛来塩分
量の多い海岸地域においても、無塗装のまま摩擦接合用
高力ボルトとしての使用が可能であり、その上熱処理コ
ストも少なくてすむため産業上極めて有用である。The high-strength bolt made of the steel of the present invention can be used as a high-strength bolt for friction welding without coating even in a coastal area where the amount of incoming salt is large, and the heat treatment cost is low. It is extremely useful in industry.
フロントページの続き (56)参考文献 特開2000−119815(JP,A) 特開2000−63993(JP,A) 特開2000−54066(JP,A) 特開 平11−172370(JP,A) 特開 平6−220576(JP,A) 特開 平6−212346(JP,A) 特開 昭62−86149(JP,A) 特開 平10−36940(JP,A) 特開 平5−51668(JP,A) (58)調査した分野(Int.Cl.7,DB名) C22C 38/00 Continuation of the front page (56) Reference JP 2000-119815 (JP, A) JP 2000-63993 (JP, A) JP 2000-54066 (JP, A) JP 11-172370 (JP, A) JP-A-6-220576 (JP, A) JP-A-6-212346 (JP, A) JP-A-62-86149 (JP, A) JP-A-10-36940 (JP, A) JP-A-5-51668 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) C22C 38/00
Claims (4)
と、Si:0.15%以下と、Mn:0.3〜0.6%
と、P:0.01%以下と、S:0.01%以下と、A
l:0.01〜0.05%と、N:0.002〜0.0
1%と、Ni:1〜2%と、Mo:0.1〜0.3%
と、Ti:0.01〜0.05%と、B:0.0003
〜0.005%と、残部Fe及び不可避的不純物とから
なる、海岸耐候性に優れた高強度鋼。1. C: 0.15 to 0.3 % by mass %
And Si: 0.15% or less, Mn: 0.3 to 0.6%
, P: 0.01% or less, S: 0.01% or less, A
1: 0.01-0.05%, N: 0.002-0.0
1%, Ni: 1-2%, Mo: 0.1-0.3%
And Ti: 0.01 to 0.05%, B: 0.0003
~ 0.005% and the balance Fe and unavoidable impurities
Becomes, coastal weather resistance excellent high strength steel.
0.1〜0.5%、Cr:0.3〜1%のうちの一種ま
たは二種を含有する、請求項1に記載の海岸耐候性に優
れた高強度鋼。2. As a steel component, in addition by mass% Cu:
The high-strength steel excellent in coastal weather resistance according to claim 1, containing one or two of 0.1 to 0.5% and Cr: 0.3 to 1%.
ルト。3. A bolt having the steel component according to claim 1 or 2.
ット。4. A nut having the steel component according to claim 1 or 2.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11630799A JP3458762B2 (en) | 1998-08-13 | 1999-04-23 | High-strength steel with excellent shore weather resistance |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP10-229041 | 1998-08-13 | ||
JP22904198 | 1998-08-13 | ||
JP11630799A JP3458762B2 (en) | 1998-08-13 | 1999-04-23 | High-strength steel with excellent shore weather resistance |
Publications (2)
Publication Number | Publication Date |
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JP2000119814A JP2000119814A (en) | 2000-04-25 |
JP3458762B2 true JP3458762B2 (en) | 2003-10-20 |
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ID=26454669
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CN105002427B (en) * | 2015-05-27 | 2017-03-22 | 钢铁研究总院 | Industrial stable high-performance bolt steel and manufacturing method thereof |
CN114908303B (en) * | 2022-04-28 | 2022-11-15 | 宁波金鼎紧固件有限公司 | Composite material for fastener and preparation method thereof |
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