JPH06264194A - High strength martensitic stainless steel excellent in rust resistance and drilling tapping screw - Google Patents
High strength martensitic stainless steel excellent in rust resistance and drilling tapping screwInfo
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- JPH06264194A JPH06264194A JP161194A JP161194A JPH06264194A JP H06264194 A JPH06264194 A JP H06264194A JP 161194 A JP161194 A JP 161194A JP 161194 A JP161194 A JP 161194A JP H06264194 A JPH06264194 A JP H06264194A
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- value
- rust resistance
- stainless steel
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は耐銹性を必要とする用途
に使用される高強度マルテンサイト系ステンレス鋼に関
わり、更に詳しくは例えばねじ込み性および耐銹性に優
れたねじ、打ち抜き性および耐銹性に優れた釘、耐銹性
に優れた刃物および耐銹性に優れた高強度ばねに関する
ものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength martensitic stainless steel used for applications requiring rust resistance, and more specifically, for example, screws excellent in screwability and rust resistance, punchability and The present invention relates to a nail having excellent rust resistance, a blade having excellent rust resistance, and a high-strength spring having excellent rust resistance.
【０００２】[0002]
【従来の技術】従来、炭素鋼製品および表面処理鋼板の
ねじ止め加工においては、炭素鋼製の図１に示すような
ドリリングタッピンねじと呼ばれる特殊ねじが使用され
ている。そして、作業効率向上やコスト低減のため、下
穴や中穴加工を実施せずに図２に示すように鋼板表面か
ら直接ねじ込み加工する工法が実施されている。すなわ
ち、ねじの先端がドリル状に刃先加工され、鋼板および
鉄板の下部構造物をドリリングすると同時にねじ部でタ
ッピングする工法が採られている。しかし、近年、酸性
雨等の地球環境の悪化に伴い、炭素鋼ドリリングタッピ
ンねじの高耐銹化すなわちステンレス化が要求されるよ
うになってきた。2. Description of the Related Art Conventionally, a special screw called a drilling tapping screw made of carbon steel as shown in FIG. 1 is used for screwing a carbon steel product and a surface-treated steel plate. Then, in order to improve work efficiency and reduce costs, a method of directly screwing from the surface of the steel sheet is carried out as shown in FIG. That is, a method is adopted in which the tip of the screw is drilled into a cutting edge, and the lower structure of the steel plate and the iron plate is drilled and tapped at the screw portion at the same time. However, in recent years, along with the deterioration of the global environment such as acid rain, it has been required that the carbon steel drilling tapping screws have high rust resistance, that is, stainless steel.
【０００３】又、近年、感性・耐銹性の観点からステン
レス鋼製品が建築・建材や車両等に幅広く使用されるよ
うになってきた。この種のステンレス鋼製品は主に構造
物の表面にスポット溶接やねじ止め加工により張り付け
られて使用されてきた。ねじ止め加工に際し、ステンレ
ス鋼ねじが使用されてきたが、硬さ不足のため、ドリリ
ングタッピンねじ化ができなかった。そのため、従来は
図３に示すようにねじが挿入できるように下穴加工され
た鉄鋼構造物と穴開け（中穴）加工されたステンレス鋼
製品の両穴部を整合させ、ステンレス鋼ねじをその両方
の穴部を通して止めていた。しかし、作業効率向上やコ
スト低減のためステンレス鋼ねじのドリリングタッピン
ねじ化が要求されるようになってきた。In recent years, stainless steel products have come to be widely used in construction / construction materials, vehicles and the like from the viewpoint of sensitivity and rust resistance. This type of stainless steel product has been mainly used by being attached to the surface of a structure by spot welding or screwing. Stainless steel screws have been used for screwing, but due to insufficient hardness, drilling tapping screws could not be used. Therefore, conventionally, as shown in FIG. 3, both holes of a steel structure that has been pre-drilled so that a screw can be inserted and a stainless steel product that has been drilled (medium hole) are aligned, and the stainless steel screw is It was stopped through both holes. However, in order to improve work efficiency and reduce costs, it has become necessary to use drilling tapping screws for stainless steel screws.
【０００４】このようなステンレス製のドリリングタッ
ピンねじ用材料に対し、５mm以上の鉄板にねじ込むため
に、ねじの刃先部はビッカース硬さで５００以上が、ね
じ部では４００以上が要求される。又、ねじの頭部は鋼
板の表面に露出するためＳＵＳ３０４と同等の耐銹性が
要求される。又、ねじの頭部および軸部はねじ込み時に
損傷しないように衝撃値で６０J/cm2 以上の高靭性が要
求される。更にねじ用素材には刃先加工やねじ切り加工
およびヘッディング加工が容易であることが要求され
る。このように製品加工前の素材は、高冷間加工性を有
し、かつ使用時に、強度がビッカース硬さで５００以
上、耐銹性がＳＵＳ３０４並および高靭性の特性を持つ
材料が要求される。In order to screw such a stainless steel drilling tapping screw material into an iron plate of 5 mm or more, the Vickers hardness of the cutting edge of the screw is required to be 500 or more, and 400 or more is required in the threaded portion. Further, since the head of the screw is exposed on the surface of the steel plate, rust resistance equivalent to that of SUS304 is required. Further, the head and shaft of the screw are required to have a high toughness of 60 J / cm 2 or more in impact value so as not to be damaged during screwing. Further, the thread material is required to be easily subjected to cutting edge processing, thread cutting processing and heading processing. As described above, the material before product processing is required to have a material having high cold workability, strength of 500 or more in Vickers hardness, and rust resistance of SUS304 and high toughness when used. .
【０００５】従来、このような材料として、高加工硬化
特性を有するオーステナイト系ステンレス鋼の適用が試
みられているが、従来材は冷間加工性および工具寿命に
劣っている。Conventionally, as such a material, an austenitic stainless steel having high work hardening characteristics has been tried to be applied, but the conventional material is inferior in cold workability and tool life.
【０００６】又、オーステナイト系ステンレス鋼のＳＵ
Ｓ３０５やＳＵＳＸＭ７等を冷間加工後、窒化処理によ
り硬化させた製品がある。しかし、これら表面窒化処理
材の耐銹性はＳＵＳ３０４より劣っている。又、マルテ
ンサイト系ステンレス鋼のＳＵＳ４１０を冷間加工後、
窒化焼入れした製品が提案されているが、耐銹性がＳＵ
Ｓ３０４より劣っている。又、近年、高強度、高靭性、
高耐銹性の材料としてＣ：０．１５％、Ｓｉ：０．２
％、Ｍｎ：０．６８％、Ｎｉ：６．２％、Ｃｒ：１１．
３％、Ｍｏ：２．１％、Ｎ：０．０５１％、Ｚｒ：０．
１５％系でδフェライトを含有せず、高焼入れ性のマル
テンサイト系ステンレス鋼が提案されている。しかしな
がら、Ａｃ1点が５６０℃と低いことから焼鈍時の軟化
抵抗が高く、ヘッディング加工等の高冷間加工ができな
いばかりか、焼入れ硬さがＨｖで５００以下（４８０程
度）であり、ねじ込み性に劣り目標特性を達成できない
現状にある。Further, SU of austenitic stainless steel
There is a product in which S305, SUSXM7 and the like are cold worked and then hardened by a nitriding treatment. However, the rust resistance of these surface nitriding materials is inferior to SUS304. In addition, after cold working of martensitic stainless steel SUS410,
Nitrogen-quenched products have been proposed, but rust resistance is SU
It is inferior to S304. In recent years, high strength, high toughness,
As a material with high rust resistance, C: 0.15%, Si: 0.2
%, Mn: 0.68%, Ni: 6.2%, Cr: 11.
3%, Mo: 2.1%, N: 0.051%, Zr: 0.
It has been proposed a martensitic stainless steel which is a 15% system and does not contain δ ferrite and has high hardenability. However, since the Ac 1 point is as low as 560 ° C, the softening resistance during annealing is high, and high cold working such as heading cannot be performed, and the quenching hardness is 500 or less (about 480) at Hv and screwability The current situation is that the target characteristics cannot be achieved.
【０００７】このように、現状では前記の必要特性全て
を兼備する材料は現出しておらず、ねじ止め加工は、Ｓ
ＵＳ３０５やＳＵＳＸＭ７系ステンレス鋼を冷間加工に
より強化したねじの先端にドリル形状の工具鋼を接合し
たドリリングタッピンねじが使用されている。又、炭素
鋼製のドリリングタッピンねじのねじ頭にプラスチック
製のキャップを被せてねじ頭のみに耐銹性を付与したド
リリングタッピンねじが使用されている。しかし、これ
らの工法は高価なため、一体物による開発が試みられて
いるが、上述のように目標特性を達成できる材料は現出
していない。As described above, at present, no material having all of the above-mentioned required characteristics has been developed, and the screwing process is S
A drilling tapping screw is used in which a drill-shaped tool steel is joined to the tip of a screw reinforced by cold working of US305 or SUSXM7 series stainless steel. Further, there is used a drilling tapping screw in which a screw cap of a carbon steel drilling tapping screw is covered with a plastic cap to provide only the screw head with rust resistance. However, since these construction methods are expensive, attempts have been made to develop them by using an integrated material, but as mentioned above, no material has been developed that can achieve the target characteristics.
【０００８】[0008]
【発明が解決しようとする課題】本発明はマルテンサイ
ト系ステンレス鋼において、前記問題の全てを解決した
鋼を提供することを目的とする。本発明の他の目的は、
高硬度、高耐銹性のねじ、釘、ばね等を製造する素材で
あって冷間加工性が特に優れた線材を安価に提供するこ
とを目的とする。本発明の他の目的は耐銹性とねじ込み
性に優れたドリリングタッピンねじを安価に提供するこ
とを目的とする。本発明者らは以上の目的を達成するた
めに、以下に述べる技術を開発したものである。SUMMARY OF THE INVENTION It is an object of the present invention to provide a martensitic stainless steel which solves all the above problems. Another object of the present invention is to
It is an object of the present invention to provide a wire rod, which is a material for manufacturing screws, nails, springs and the like having high hardness and high rust resistance, and which has particularly excellent cold workability, at low cost. Another object of the present invention is to provide a drilling tapping screw excellent in rust resistance and screwability at low cost. The present inventors have developed the following technology in order to achieve the above object.
【０００９】[0009]
【課題を解決するための手段】すなわち、本発明はマル
テンサイト系ステンレス鋼の成分について種々究明した
ところ、重量％で、Ｓｉを０．１〜０．５％、Ｍｎを
０．１〜２％、Ｃｒを１２．０〜１６．０％、Ｍｏを
１．３〜３．５％含有し、かつ、下記の（１），（２）
式で表されるＡＲＩの値が１６〜２１（％）、ＤＩの値
が０（％）未満で、マルテンサイト組織、又は、焼戻し
マルテンサイト組織を有し、０．２μｍ以上のＣｒ炭化
物がない場合に、マルテンサイト系ステンレス鋼で耐銹
性がＳＵＳ３０４並、すなわち、孔食発生電位が２００
mV以上になることを見出した。 ＡＲＩ＝Ｃｒ＋2.4 Ｍｏ ………（１）式 ＤＩ ＝Ｃｒ＋1.21Ｍｏ＋0.48Ｓｉ＋2.48Ａｌ −（24.5Ｃ＋18.4Ｎ＋Ｎｉ＋0.11Ｍｎ）−10.0 ………（２）式[Means for Solving the Problems] That is, according to the present invention, various components of martensitic stainless steel have been investigated, and in terms of weight%, Si is 0.1 to 0.5% and Mn is 0.1 to 2%. , Cr 12.0 to 16.0%, Mo 1.3 to 3.5%, and the following (1), (2)
The value of ARI represented by the formula is 16 to 21 (%), the value of DI is less than 0 (%), and it has a martensite structure or a tempered martensite structure, and there is no Cr carbide of 0.2 μm or more. In this case, the rust resistance of martensitic stainless steel is about SUS304, that is, the pitting corrosion generation potential is 200.
It was found that it would be over mV. ARI = Cr + 2.4 Mo ... (1) Formula DI = Cr + 1.21Mo + 0.48Si + 2.48Al- (24.5C + 18.4N + Ni + 0.11Mn) -10.0 ... (2) Formula
【００１０】更に、本発明者らは前記ステンレス鋼にお
いて、Ｎｉを１．０〜２．５％、Ｃを０．１３〜０．２
％、Ｎを０．０６〜０．１３％添加し、かつ、（３）式
で表されるマルテンサイト量指標であるＭＩの値が０
（％）未満の場合、焼入れ後又、焼入れ・焼戻し後のマ
ルテンサイト硬さがＨｖ≧５００になることを見出し
た。 ＭＩ ＝Ｎｉ＋30Ｃ＋0.12Ｍｎ＋18Ｎ＋0.83（Ｃｒ＋1.5 Ｓｉ＋1.4 Ｍｏ） −25.0 ………（３）式Further, the inventors of the present invention have added 1.0 to 2.5% of Ni and 0.13 to 0.2 of C in the above stainless steel.
%, N of 0.06 to 0.13%, and the value of MI, which is an index of the amount of martensite represented by the formula (3), is 0.
It has been found that when it is less than (%), the martensite hardness after quenching and after quenching / tempering is Hv ≧ 500. MI = Ni + 30C + 0.12Mn + 18N + 0.83 (Cr + 1.5Si + 1.4Mo) -25.0 ………… (3)
【００１１】更に、又、本発明者らは上記ステンレス鋼
の成分において、Ｎｉを１．０〜２．５％とし、Ａｃ1
を６５０℃以上にして、（４）式で表される冷間加工性
指標であるＷ１の値を２６０（％）未満にすると、焼鈍
時に軟化抵抗が低いため冷間加工性に優れ、割れなくね
じ頭等の高冷間加工ができることを見出した。 Ｗ１ ＝24Ｍｏ＋13.3Ｃｒ＋６Ｍｎ＋６Ｓｉ＋Ｎｉ ………（４）式 すなわち、前記諸成分と（１）〜（４）式を満足し、か
つマルテンサイト組織（焼戻し組織を含む）を有するス
テンレス鋼はＳＵＳ３０４並の優れた耐銹性とＨｖ≧５
００のマルテンサイト硬さを有し、更に、前記諸成分と
（１）〜（４）式を満足する鋼は熱間圧延材を焼鈍後、
冷間加工する際に、著しく向上した冷間加工性を示す。
そのため、熱延後焼鈍処理された線材は引張強度が９５
０N/mm2以下であって、極めて冷間加工性に優れてい
る。なお、前記の線材圧延後の焼鈍は、処理時間を短縮
するために２段焼鈍、すなわち、１回目の焼鈍では７０
０〜８００℃で０．５時間以上保定し、その後、１００
℃以下まで冷却し、続いて２回目の焼鈍では６００〜７
５０℃で０．５時間以上保定する。Furthermore, the present inventors have set the content of Ni to 1.0 to 2.5% in the above-mentioned stainless steel composition and set Ac 1
Is 650 ° C. or higher and the value of W1 which is the cold workability index represented by the formula (4) is less than 260 (%), the cold workability is excellent because the softening resistance is low at the time of annealing and there is no cracking. It was found that high cold working such as screw head can be performed. W1 = 24Mo + 13.3Cr + 6Mn + 6Si + Ni Formula (4) That is, the stainless steel satisfying the above-mentioned components and the formulas (1) to (4) and having a martensite structure (including a tempered structure) is as excellent as SUS304. Corrosion resistance and Hv ≧ 5
A steel having a martensite hardness of 00 and further satisfying the above-mentioned various components and the formulas (1) to (4) is obtained by annealing a hot rolled material,
When cold working, it exhibits significantly improved cold workability.
Therefore, the wire rod annealed after hot rolling has a tensile strength of 95.
It is 0 N / mm 2 or less and is extremely excellent in cold workability. The annealing after the wire rod rolling is a two-step annealing in order to shorten the processing time, that is, 70 times in the first annealing.
Hold at 0-800 ℃ for 0.5 hours or more, then 100
It is cooled to below ℃, and then 600 to 7 in the second annealing.
Hold at 50 ° C for 0.5 hour or longer.
【００１２】前記の鋼成分に加えて、Ｂを０．００１〜
０．０１０％添加すると焼鈍後の線材引張強度が９３０
N/mm2 以下になって、更に冷間加工性を向上できる。
又、その後の焼入れ後のマルテンサイトの硬さがＨｖ≧
５２０になり、かつ、靭性を向上することができる。又
Ｔｉを０．０５〜１．０％、Ｎｂを０．０５〜１．０％
添加すると耐銹性を更に向上することができる。又、下
記（５）式で表される冷間加工性指標であるＷ２の値を
２６０（％）未満にすると、焼鈍時に軟化抵抗が低いた
め冷間加工性に優れ、割れなくねじ頭等の高冷間加工が
できる。 Ｗ２＝24Ｍｏ＋13.3Ｃｒ＋６Ｍｎ＋６Ｓｉ＋Ｎｉ＋10Ｔｉ＋10Ｎｂ…（５）式In addition to the above steel components, B is 0.001-
When 0.010% is added, the wire tensile strength after annealing is 930.
N / mm 2 or less, further improving the cold workability.
Further, the hardness of the martensite after the subsequent quenching is Hv ≧
520 and toughness can be improved. Also, Ti is 0.05 to 1.0% and Nb is 0.05 to 1.0%.
If added, rust resistance can be further improved. When the value of W2, which is the cold workability index represented by the following formula (5), is less than 260 (%), the softening resistance is low at the time of annealing, so that the cold workability is excellent, and the screw heads without cracking are formed. High cold working is possible. W2 = 24Mo + 13.3Cr + 6Mn + 6Si + Ni + 10Ti + 10Nb (5) Formula
【００１３】前述したマルテンサイト系ステンレス鋼は
ねじ込み性と耐銹性を必要とするドリリングタッピンね
じを製造するのに極めて適している。すなわち、熱延線
材を焼鈍した後、容易にねじを成形することができ、更
にこれを例えば好ましい範囲として１０５０〜１３００
℃の温度範囲から０．５℃/s以上の冷却速度で焼入れ
し、続いて１００〜４００℃の温度範囲で焼戻しするこ
とにより、刃先硬さがＨｖで５００以上で、厚さが５．
５mmのＳＳ４００の鋼板にねじ込み可能なドリリングタ
ッピンねじを製造することができる。The above-mentioned martensitic stainless steel is extremely suitable for producing a drilling tapping screw which requires screwability and rust resistance. That is, after the hot-rolled wire is annealed, the screw can be easily formed.
By quenching at a cooling rate of 0.5 ° C./s or more from the temperature range of 100 ° C., and subsequently tempering at a temperature range of 100 to 400 ° C., the edge hardness is Hv of 500 or more and the thickness is 5.
It is possible to manufacture a drilling tapping screw that can be screwed into a 5 mm SS400 steel plate.
【００１４】[0014]
【作用】先ず、本発明のマルテンサイト系ステンレス鋼
の成分範囲の限定理由について具体的に述べる。First, the reason for limiting the composition range of the martensitic stainless steel of the present invention will be specifically described.
【００１５】Ｃはマルテンサイト系ステンレス鋼のビッ
カース硬さ５００以上を確保するために０．１３％以上
（以下全て重量％）添加する。しかし、０．２０％を超
えて添加すると粗大炭化物を析出させて耐銹性や冷間加
工性を低下させるばかりか、ＭＩの値が大きくなって残
留オーステナイト組織が存在して焼入れ硬さを低下させ
ることから、上限を０．２０％に限定した。C is added in an amount of 0.13% or more (hereinafter, all weight%) in order to secure a Vickers hardness of 500 or more of martensitic stainless steel. However, if added in excess of 0.20%, not only does coarse carbide precipitate to reduce rust resistance and cold workability, but also the MI value increases and a retained austenite structure exists and quenching hardness decreases. Therefore, the upper limit is limited to 0.20%.
【００１６】Ｓｉは脱酸のために必要な元素であるが、
０．５％を超えて添加すると冷間加工性を著しく低下さ
せることから、上限を０．５％に限定した。又、０．１
％未満では脱酸効果を得ることができないので下限を
０．１％とした。Ｍｎは脱酸のため、オーステナイトの
生成のためおよびＮ固溶のため添加するが、２．０％を
超えて添加すると耐銹性を低下させるばかりか、ＭＩの
値が大きくなって残留オーステナイト組織が存在し、焼
入れ硬さを低下させることから、上限を２．０％に限定
した。又、０．１％未満では上記の効果が得られないの
で下限を０．１％とした。Si is an element necessary for deoxidation,
If added in excess of 0.5%, the cold workability is significantly reduced, so the upper limit was limited to 0.5%. Also, 0.1
If it is less than%, the deoxidizing effect cannot be obtained, so the lower limit was made 0.1%. Mn is added for deoxidization, for the formation of austenite and for N solid solution, but if it is added in excess of 2.0%, not only the rust resistance decreases but also the MI value increases and the retained austenite structure increases. Exists, and the quenching hardness is reduced, so the upper limit was limited to 2.0%. If it is less than 0.1%, the above effect cannot be obtained, so the lower limit is made 0.1%.
【００１７】ＣｒはＭＩの値を低下させて残留オーステ
ナイト組織を減少して、マルテンサイト組織を有効に得
るためと、（１）式のＡＲＩの値を大きくして耐銹性を
付与するために１２．０％以上添加する。しかし、１
６．０％を超えて添加すると（２）式のＤＩの値が過大
となってδフェライト組織が存在し、焼入れ硬さおよび
耐銹性を著しく低下させるため上限を１６．０％に限定
した。ＭｏはＡＲＩの値を増大して耐銹性を付与するた
めと靭性を改善するために１．３％以上添加する。しか
し、３．５％を超えて添加するとその効果は飽和するば
かりか、ＤＩの値が過大となってδフェライト組織が存
在し、焼入れ硬さおよび耐銹性を著しく低下させるため
上限を３．５％に限定した。Cr reduces the MI value to reduce the retained austenite structure and effectively obtains the martensite structure, and to increase the ARI value in the formula (1) to impart rust resistance. Add 12.0% or more. But 1
When added in excess of 6.0%, the value of DI in the formula (2) becomes excessive and a δ ferrite structure exists, and quenching hardness and rust resistance are significantly reduced, so the upper limit was limited to 16.0%. . Mo is added in an amount of 1.3% or more in order to increase the ARI value to impart rust resistance and to improve toughness. However, if added in excess of 3.5%, not only the effect will be saturated, but also the value of DI will become excessive and a δ ferrite structure will be present, and quenching hardness and rust resistance will be significantly reduced, so the upper limit is 3. Limited to 5%.
【００１８】Ｎｉはマルテンサイト組織の靭性を高める
ために１．０％以上添加する。しかし、２．５％を超え
て添加してもその効果は飽和し、経済的でない。又、Ａ
ｃ1温度を低下させるため焼鈍温度が低くなり、軟化し
難く、冷間加工性に劣る。又、２．５％を超えると応力
腐食割れ感受性が高くなるばかりか、（３）式のＭＩの
値が増大して残留オーステナイト組織が存在し、焼入れ
硬さを低下させるため上限を２．５％に限定した。Ｎは
焼入れ硬度を上昇、母材の耐銹性のためと、ＤＩの値を
低下させてδフェライト組織を抑え耐銹性を付与するた
めに０．０６％以上添加する。しかし、０．１３％を超
えて添加すると鋼中への固溶量を超えて気泡やＣｒ炭窒
化物を生成して耐銹性を低下させるため上限を０．１３
％に限定した。Ni is added in an amount of 1.0% or more in order to enhance the toughness of the martensitic structure. However, even if added over 2.5%, the effect is saturated and it is not economical. Also, A
Since the c 1 temperature is lowered, the annealing temperature is lowered, it is difficult to soften, and the cold workability is poor. Further, if it exceeds 2.5%, not only the stress corrosion cracking susceptibility becomes high, but also the MI value of the formula (3) increases and there is a retained austenite structure, which lowers the quenching hardness, so the upper limit is 2.5. Limited to%. N is added in an amount of 0.06% or more for increasing the quenching hardness and for the rust resistance of the base material and for reducing the value of DI to suppress the δ ferrite structure and impart rust resistance. However, if added in excess of 0.13%, the amount of solid solution in the steel is exceeded and bubbles or Cr carbonitrides are generated to lower the rust resistance, so the upper limit is 0.13.
Limited to%.
【００１９】Ｂは焼鈍後の強度を下げ冷間加工性を向上
させる。又、最終製品の強化に当たって、焼入れ硬さと
靭性を向上させる。更に、製造性の面から熱間加工性を
改善する。従って、上記効果が本発明鋼にとって更に必
要なとき、０．００１〜０．０１０％の範囲内で添加す
る。０．０１０％を超えるとホウ化物を析出し、逆に靭
性および熱間加工性を悪くするばかりか耐銹性を劣化さ
せることから、上限を０．０１０％に限定した。又、
０．００１％未満では上記効果が得られないので下限を
０．００１％とした。Ｔｉは冷却中にＣｒ炭窒化物を抑
え耐銹性を向上させる有効な元素であり、必要によって
添加する。１．０％超添加すると上記効果は飽和し、経
済的でないことから上限を１．０％とし、その効果が得
られる下限値を０．０５％とした。Ｎｂは冷却中にＣｒ
炭窒化物を抑え耐銹性を向上させる有効な元素であり、
必要によって添加する。１．０％超添加するとその効果
は飽和し、０．０５％未満ではその効果が得られないの
で０．０５〜１．０％の範囲とした。B reduces the strength after annealing and improves the cold workability. Further, in strengthening the final product, it improves quenching hardness and toughness. Furthermore, hot workability is improved in terms of manufacturability. Therefore, when the above effect is further required for the steel of the present invention, it is added within the range of 0.001 to 0.010%. If it exceeds 0.010%, boride is precipitated, and on the contrary, not only the toughness and hot workability are deteriorated but also the rust resistance is deteriorated. Therefore, the upper limit is limited to 0.010%. or,
If less than 0.001%, the above effect cannot be obtained, so the lower limit was made 0.001%. Ti is an effective element that suppresses Cr carbonitride during cooling and improves rust resistance, and is added if necessary. If added over 1.0%, the above effect is saturated and it is not economical, so the upper limit was made 1.0% and the lower limit at which the effect was obtained was made 0.05%. Nb is Cr during cooling
It is an effective element that suppresses carbonitrides and improves rust resistance.
Add as needed. If added over 1.0%, the effect is saturated, and if less than 0.05%, the effect cannot be obtained, so the range was made 0.05 to 1.0%.
【００２０】次に本発明で特定した（１）〜（４）の各
式について説明する。ＡＲＩの式は母材の耐銹性に対す
る各種元素の影響を調査した結果得られたもので、耐銹
性に対し効果のある元素とその影響度を示すものであ
る。耐銹性に対しては、ＣｒとＭｏが最も影響を与え
る。ＡＲＩは母材の耐銹性向上のために１６（％）以上
にするが、２１（％）を超えると製造性を悪くするため
上限を２１（％）に限定した。Next, the formulas (1) to (4) specified in the present invention will be described. The ARI formula is obtained as a result of investigating the influence of various elements on the rust resistance of the base material, and shows the element effective on the rust resistance and its influence degree. Cr and Mo have the greatest effect on rust resistance. The ARI is set to 16 (%) or more to improve the rust resistance of the base material, but if it exceeds 21 (%), the manufacturability is deteriorated, so the upper limit is limited to 21 (%).
【００２１】ＤＩの式は母材中のδフェライト量に対す
る各種元素の影響を調査した結果得られたもので、δフ
ェライト量に対し効果のある元素とその影響度を示すも
のである。Ｃｒ，Ｍｏ，Ｓｉ，Ｃ，Ｎ，Ｎｉ，Ｍｎが影
響を与える。ＤＩの値が０（％）を超えるとδフェライ
トが存在し、焼入れ硬さおよび靭性を低下させるばかり
か、焼入れ時にδフェライト界面に炭窒化物を析出さ
せ、耐銹性を著しく低下させるため０（％）未満に限定
した。The formula of DI is obtained as a result of investigating the influence of various elements on the amount of δ ferrite in the base material, and shows the element effective for the amount of δ ferrite and its influence degree. Cr, Mo, Si, C, N, Ni, Mn have an influence. When the DI value exceeds 0 (%), δ ferrite is present, which not only lowers the quenching hardness and toughness, but also causes carbonitrides to precipitate at the δ ferrite interface during quenching, significantly reducing rust resistance. Limited to less than (%).
【００２２】ＭＩの式は母材中のマルテンサイト組織量
に対する各種元素の影響を調査した結果得られたもの
で、マルテンサイト組織量に対し効果のある元素とその
影響度を示すものである。ＭＩの値が０（％）を超える
と焼入れ組織中にオーステナイト組織が散在し、ビッカ
ース硬さで５００以下になるため０（％）未満に限定し
た。The MI formula is obtained as a result of investigating the influence of various elements on the martensite structure amount in the base metal, and shows the element effective on the martensite structure amount and its influence degree. When the MI value exceeds 0 (%), the austenite structure is scattered in the quenched structure, and the Vickers hardness is 500 or less, so it was limited to less than 0 (%).
【００２３】Ｗ１の式は母材の焼鈍時の軟化抵抗に対す
る各元素の影響を調査した結果得られたもので、焼鈍時
の軟化抵抗に対し効果のある元素とその影響度を示すも
のである。Ｗ１の値が２６０（％）を超えると軟化抵抗
が高くなり、焼鈍後の硬さがビッカース硬さで３００以
上となり、製品の成形性が悪くなるため２６０（％）に
限定した。Ｗ２の式は母材の焼鈍時の軟化抵抗に対し効
果のある元素とその影響度を示すものである。Ｗ２の値
が２６０（％）を超えると軟化抵抗が高くなり、焼鈍後
の硬さがビッカース硬さで３００以上となり、製品の成
形性が悪くなるため２６０（％）に限定した。The formula of W1 is obtained as a result of investigating the influence of each element on the softening resistance during annealing of the base material, and shows the element effective on the softening resistance during annealing and its influence degree. . When the value of W1 exceeds 260 (%), the softening resistance becomes high, the hardness after annealing becomes Vickers hardness of 300 or more, and the formability of the product deteriorates, so the limit was set to 260 (%). The formula of W2 shows an element effective for the softening resistance during annealing of the base material and its influence degree. When the value of W2 exceeds 260 (%), the softening resistance becomes high, the hardness after annealing becomes Vickers hardness of 300 or more, and the formability of the product deteriorates, so the limit was set to 260 (%).
【００２４】本発明は以上の成分と以下の組織から構成
される。本発明鋼はマルテンサイト組織又は焼戻しマル
テンサイト組織からなる。Ｃｒ炭化物、特に旧オーステ
ナイト粒界のＣｒ炭化物は耐銹性を劣化せしめるので鋼
組織中に析出せしめない方がよい。図４はＣｒ：１３．
０％、Ｎｉ：２．４％、Ｍｏ：２．０％、Ｃ：０．１５
％、Ｎ：０．１％、残部Ｆｅからなるマルテンサイト系
ステンレス鋼を本発明の工程で処理する際、焼入れ時の
冷却速度を変えて得られたＣｒ炭化物の平均粒径と孔食
発生電位（耐銹性を表す）の関係を示したもので、Ｃｒ
炭化物が零（粒径：零）の場合が最も耐銹性が良好であ
る。しかし、Ｃｒ炭化物の粒径が０．２μｍ超になると
急激に孔食発生電位が低くなり、耐銹性が著しく劣化す
る。従って、本発明鋼ではＣｒ炭化物の平均粒径の上限
を０．２μｍとする。以上の成分と組織を有するマルテ
ンサイト系ステンレス鋼はＳＵＳ３０４並以上（孔食発
生電位：２００mV以上）の耐銹性とＨｖが５００以上の
マルテンサイト硬さを示す高硬度特性を具備するのであ
る。The present invention comprises the above components and the following tissues. The steel of the present invention has a martensite structure or a tempered martensite structure. Since Cr carbides, especially Cr carbides in the former austenite grain boundary, deteriorate the rust resistance, it is better not to precipitate them in the steel structure. FIG. 4 shows Cr: 13.
0%, Ni: 2.4%, Mo: 2.0%, C: 0.15
%, N: 0.1% and the balance Fe, when the martensitic stainless steel is treated in the process of the present invention, the average grain size and pitting corrosion potential of Cr carbide obtained by changing the cooling rate during quenching It shows the relationship of (representing rust resistance), Cr
The best rust resistance is obtained when the carbide content is zero (particle size: zero). However, when the grain size of Cr carbide exceeds 0.2 μm, the pitting corrosion generation potential is rapidly lowered, and the rust resistance is significantly deteriorated. Therefore, in the steel of the present invention, the upper limit of the average grain size of Cr carbide is set to 0.2 μm. The martensitic stainless steel having the above components and structure has rust resistance equal to or higher than SUS304 (pitting corrosion generation potential: 200 mV or higher) and high hardness characteristics showing martensite hardness with Hv of 500 or higher.
【００２５】次に上記ステンレス鋼を製造する方法につ
いて説明する。本発明の上記成分を有する鋼を溶製し、
溶鋼を鋳造によってビレットを形成し、該ビレットを加
熱後熱間圧延を施し、熱延線材を製造する。前記熱間圧
延材は高焼入れ性を示すため、熱間の終了温度にも関わ
らず、熱間圧延終了後に熱延線材に焼きが入り、１５０
０N/mm2 以上の引張強度を示す。従って、該線材を後工
程で高冷間加工を施すため、該線材に焼鈍を施して線材
の引張強度を９５０N/mm2 以下にする。Next, a method for producing the above stainless steel will be described. Smelting steel having the above components of the present invention,
A billet is formed by casting molten steel, and the billet is heated and then hot-rolled to manufacture a hot-rolled wire rod. Since the hot-rolled material exhibits high hardenability, the hot-rolled wire material is hardened after completion of hot-rolling regardless of the hot-termination temperature.
It shows a tensile strength of 0 N / mm 2 or more. Therefore, in order to subject the wire rod to high cold working in a post-process, the wire rod is annealed so that the tensile strength of the wire rod is 950 N / mm 2 or less.
【００２６】上記線材はＡｃ1 温度が７５０℃未満と低
いため、通常の焼鈍（焼鈍温度：６００〜８００℃）で
９５０N/mm2 以下の引張強度を得るためには５００〜１
０００時間程度の焼鈍時間が必要である。このため１回
目の焼鈍（Ａｃ1 以上）を７００〜８００℃の温度範囲
で０．５〜５０時間保定し、１００℃以下まで冷却した
後、続いて２回目の焼鈍（Ａｃ1 以下）を６００〜７５
０℃の温度範囲で０．５〜５０時間保定して冷却する２
段焼鈍を行うことが好ましい。Since the above-mentioned wire has a low Ac 1 temperature of less than 750 ° C., it is necessary to obtain a tensile strength of 500 to 1 in order to obtain a tensile strength of 950 N / mm 2 or less by ordinary annealing (annealing temperature: 600 to 800 ° C.).
An annealing time of about 000 hours is required. Therefore, the first annealing (Ac 1 or more) is held in the temperature range of 700 to 800 ° C. for 0.5 to 50 hours, cooled to 100 ° C. or less, and then the second annealing (Ac 1 or less) is 600. ~ 75
Cool and hold for 0.5 to 50 hours in the temperature range of 0 ° C 2
It is preferable to perform step annealing.
【００２７】このように焼鈍を行って引張強度を９５０
N/mm2 以下にした後、伸線加工（減面率：１〜９５％）
を行い、その後、必要により通常の焼鈍、例えば６００
〜８００℃の温度範囲で１〜２０分間の保持の焼鈍を施
し、該線材に切削、鍛造等の冷間加工を行い製品とす
る。いずれにせよ、冷間加工前の線材の引張強度を９５
０N/mm2 以下にすることが重要である。Annealing was performed in this manner to obtain a tensile strength of 950.
After N / mm 2 or less, wire drawing (area reduction rate: 1 to 95%)
And then, if necessary, normal annealing, eg 600
Annealing is performed for 1 to 20 minutes in a temperature range of to 800 ° C., and the wire material is subjected to cold working such as cutting and forging to obtain a product. In any case, the tensile strength of the wire before cold working should be 95
It is important to keep it below 0 N / mm 2 .
【００２８】線材に冷間加工を施して、製品にした後、
１０５０〜１３００℃の温度範囲で１〜２００分の加熱
保持を施し、続いて０．５〜２０℃/sの冷却速度で室温
まで急冷して焼入れを行う。本発明の成分を有する鋼に
からみ焼入れを施す（特に冷却速度の制御）ことによっ
てＣｒ炭化物の粒径を０．２μｍ以下に制御することが
できると共に、マルテンサイト組織を得ることができ
る。After cold working the wire to make a product,
Heating and holding is performed for 1 to 200 minutes in a temperature range of 1050 to 1300 ° C., and then quenching is performed by rapidly cooling to room temperature at a cooling rate of 0.5 to 20 ° C./s. By subjecting the steel having the components of the present invention to entanglement quenching (particularly controlling the cooling rate), the grain size of Cr carbide can be controlled to 0.2 μm or less, and a martensitic structure can be obtained.
【００２９】かかる鋼組織は、孔食発生電位が２００mV
以上の高耐銹性とＨｖが５００以上の高硬度を有するこ
とができる。この特性は、靭性を付与するために焼入れ
後、１００〜４００℃×３〜２００分の焼戻し処理を施
しても同様に得られる。以上のように、本発明のマルテ
ンサイト系ステンレス鋼は高冷間加工性と高強度・高耐
銹性を有することができるので図１に示すドリリングタ
ッピンねじを製造するのに好適である。The steel structure has a pitting corrosion potential of 200 mV.
It can have high rust resistance and Hv of 500 or higher. This property can be obtained similarly even after tempering for imparting toughness and tempering treatment at 100 to 400 ° C. for 3 to 200 minutes. As described above, the martensitic stainless steel of the present invention can have high cold workability, high strength, and high rust resistance, and is therefore suitable for producing the drilling tapping screw shown in FIG.
【００３０】次に該ドリリングタッピンねじの製造工程
を説明する。本発明鋼ビレットを熱間圧延した後、該熱
延線材に焼鈍、例えば前述の２段焼鈍を施し、続いて伸
線加工を行って所望の線径にした後、通常の焼鈍を施
し、ドリリングタッピンねじを成形する。線材は９５０
N/mm2 以下の引張強度になっているのでヘッディング等
の加工は容易である。Next, the manufacturing process of the drilling tapping screw will be described. After hot-rolling the steel billet of the present invention, the hot-rolled wire is annealed, for example, the two-stage annealed as described above, followed by wire drawing to obtain a desired wire diameter, and then an ordinary annealing and drilling. Form the tapping screw. Wire material is 950
Since the tensile strength is N / mm 2 or less, processing such as heading is easy.
【００３１】ドリリングタッピンねじを成形した後、該
ねじを１０５０〜１３００℃の温度に加熱し、１〜２０
０分保持した後、０．５〜２０℃/sの冷却速度で冷却し
て、焼入れ処理を施す。焼入れ温度が１０５０℃未満で
あると、Ｃｒ炭化物が析出して耐銹性および靭性が劣化
するばかりか、固溶Ｃ量が減り焼入れ強度が得られずね
じ込み性を劣化させるため、焼入れ温度を１０５０℃以
上にする。しかし、１３００℃を超えると残留オーステ
ナイトおよびδフェライトが存在し、逆に焼入れ強度、
ねじ込み性が低下するばかりか、耐銹性、靭性が劣化す
るため焼入れ温度の上限を１３００℃とする。又、焼入
れ時の冷却速度が０．５℃/s未満であると、粒界にＣｒ
炭化物が析出して耐銹性が劣化するため、冷却速度を
０．５℃/s以上にする。しかし、２０℃/sを超えると焼
入れ時に焼割れが起こるため冷却速度の上限を２０℃/s
とする。After forming the drilling tapping screw, the screw is heated to a temperature of 1050-1300 ° C. for 1-20
After holding it for 0 minutes, it is cooled at a cooling rate of 0.5 to 20 ° C./s and subjected to quenching treatment. If the quenching temperature is less than 1050 ° C., not only does Cr carbide precipitate and the rust resistance and toughness deteriorate, but also the amount of solid solution C decreases and quenching strength is not obtained, and screwability deteriorates. ℃ or above. However, if it exceeds 1300 ° C, residual austenite and δ ferrite are present, and conversely, the quenching strength,
Not only the screwability is deteriorated, but also the rust resistance and toughness are deteriorated, so the upper limit of the quenching temperature is set to 1300 ° C. Also, if the cooling rate during quenching is less than 0.5 ° C / s, Cr will not form at the grain boundaries.
Since the carbide precipitates and the rust resistance deteriorates, the cooling rate is set to 0.5 ° C / s or more. However, if it exceeds 20 ° C / s, quenching cracks occur during quenching, so the upper limit of the cooling rate is 20 ° C / s.
And
【００３２】以上の焼入れ処理を施した後、１００〜４
００℃の温度範囲に３〜２００分保持する焼戻し処理を
施し、靭性を付与する。１００℃未満では靭性を付与す
ることができず、４００℃超では硬さがＨｖで５００未
満となりねじ込み性が低下する。以上のように本発明に
よれば所望の特性を有するドリリングタッピンねじを一
体に形成することが可能となる。After the above quenching treatment, 100-4
A toughness is imparted by performing a tempering treatment in which the temperature is maintained in the temperature range of 00 ° C. for 3 to 200 minutes. If it is less than 100 ° C., toughness cannot be imparted, and if it exceeds 400 ° C., the hardness is less than 500 in Hv and the screwability is deteriorated. As described above, according to the present invention, it becomes possible to integrally form a drilling tapping screw having desired characteristics.
【００３３】[0033]
【実施例】表１（１）に本発明鋼No．１〜２４の成分
を、表１（２）に比較鋼No．２５〜４１の成分をそれぞ
れ示す。EXAMPLES Table 1 (1) shows the steel No. of the present invention. The components of Nos. 1 to 24 are shown in Table 1 (2) as Comparative Steel No. The components of 25 to 41 are shown respectively.
【００３４】本発明鋼No．１〜５と比較鋼No．２５〜２
７は１３．０Ｃｒ−２．０Ｍｏ−０．１５Ｃ−０．１０
Ｎを基本成分としてオーステナイト生成元素であるＮｉ
量（％）およびＭｎ量（％）を変化させたものである。
本発明鋼No．６〜１０と比較鋼No．２８〜３１は１４．
０Ｃｒ−２．０Ｎｉ−２．０Ｍｏ−０．５Ｍｎを基本成
分としてＣ量（％）およびＮ量（％）を変化させたもの
である。本発明鋼No．１１〜１５と比較鋼No．３２〜３
７は２．０Ｎｉ−０．２Ｍｎ−０．１５Ｃ−０．１０Ｎ
を基本成分としてＣｒ量（％）およびＭｏ量（％）を変
化させたものである。本発明鋼No．１６〜１８と比較鋼
No．３８は１３Ｃｒ−２Ｎｉ−２Ｍｏ−０．２Ｍｎ−
０．１５Ｃ−０．１０Ｎを基本成分としてＢ量（％）を
変化させたものである。本発明鋼No．１９〜２４と比較
鋼No．３９〜４１は１３．５Ｃｒ−２．０Ｎｉ−２．０
Ｍｏ−１．２Ｍｎ−０．１５Ｃ−０．１０Ｎを基本成分
としてＴｉ量（％）およびＮｂ量（％）を変化させたも
のである。Steel No. of the present invention 1 to 5 and comparative steel No. 25-2
7 is 13.0Cr-2.0Mo-0.15C-0.10.
Ni which is an austenite forming element with N as a basic component
The amount (%) and the Mn amount (%) were changed.
Invention Steel No. 6 to 10 and comparative steel No. 28-31 is 14.
The amount of C (%) and the amount of N (%) were changed with 0Cr-2.0Ni-2.0Mo-0.5Mn as a basic component. Invention Steel No. 11 to 15 and comparative steel No. 32-3
7 is 2.0Ni-0.2Mn-0.15C-0.10N
The amount of Cr (%) and the amount of Mo (%) are changed by using as a basic component. Invention Steel No. 16-18 and comparative steel
No. 38 is 13Cr-2Ni-2Mo-0.2Mn-
The amount of B (%) was changed with 0.15C-0.10N as the basic component. Invention Steel No. 19 to 24 and comparative steel No. 39-41 is 13.5Cr-2.0Ni-2.0
The amount of Ti (%) and the amount of Nb (%) were changed with Mo-1.2Mn-0.15C-0.10N as a basic component.
【００３５】以上の本発明鋼および比較鋼を通常のステ
ンレス鋼線の製造工程で、溶製し、熱間線材圧延を行
い、１０００℃で熱延を終了した。得られた熱延線材を
第１回目の焼鈍として、７４０℃まで加熱し、この温度
で４時間保持した後、５０℃まで冷却し、続いて第２回
目の焼鈍として、６５０℃まで加熱し、この温度で４時
間保持した後、室温まで冷却した。この焼鈍で得られた
線材の引張強度は８００〜１２００N/mm2 の範囲にあっ
た。上記線材を約２５％伸線加工を行った後、７００℃
×１０分間の焼鈍を施し、その後、鍛造により６角頭に
ヘッディング加工を行い、この加工材１１００℃に加熱
した後、１０分間保持した後、該温度から５℃/sの冷却
速度で焼入れを行い、更に２００℃に加熱し、３０分間
保持の焼戻し処理を施した。この結果、Ｃｒ炭化物が微
細に析出した焼戻しマルテンサイト組織のものが得られ
た。The above-described steels of the present invention and comparative steels were melted and rolled into a hot wire rod in a normal stainless steel wire manufacturing process, and hot rolling was completed at 1000 ° C. As the first annealing, the obtained hot-rolled wire was heated to 740 ° C., held at this temperature for 4 hours, cooled to 50 ° C., and then, as the second annealing, heated to 650 ° C. After holding at this temperature for 4 hours, it was cooled to room temperature. The tensile strength of the wire obtained by this annealing was in the range of 800 to 1200 N / mm 2 . Approximately 25% of the above wire rod is drawn, then 700 ° C
Annealing for × 10 minutes, and then heading is performed on the hexagonal head by forging, heating this processed material to 1100 ° C., holding for 10 minutes, and then quenching at a cooling rate of 5 ° C./s from that temperature. Then, it was further heated to 200 ° C. and tempered by holding for 30 minutes. As a result, a tempered martensite structure in which Cr carbide was finely precipitated was obtained.
【００３６】次に、該加工熱処理材の硬さ、耐銹性およ
び靭性を得るための試験を行った。硬さはＪＩＳ Ｚ２
２４４により線材の縦断面の中心硬さを測定した。本発
明例の硬さのランクはビッカース硬さ５００以上とし
た。耐銹性評価試験はＪＩＳ Ｚ２３７１により線材圧
延後の線材を平板に熱延、冷間圧延、研磨後、１００×
５０×１mmの板にて５００時間試験実施後評価した。本
発明例の耐銹性ランクはＪＩＳ評点の９．５以上とし
た。靭性はＪＩＳ Ｚ２２０２よりサイズφ７．５mm×
５５mm、深さ１mmのＵノッチで室温で試験を行い、その
時のシャルピー値にて評価した。本発明例のシャルピー
値のランクは６０J/cm2 以上とした。冷間加工性はコー
ルドダブルヘッダーにてつば付き六角頭のヘッディング
加工時に割れの有無で判断した。割れなく加工できた場
合は冷間加工性を良好、割れた場合は冷間加工性を不良
として評価した。Next, tests were conducted to obtain the hardness, rust resistance and toughness of the heat-treated material. Hardness is JIS Z2
The center hardness of the longitudinal section of the wire was measured by 244. The hardness rank of the examples of the present invention was set to Vickers hardness of 500 or more. The rust resistance evaluation test is performed according to JIS Z2371, after the wire rod after rolling is hot-rolled into a flat plate, cold-rolled, polished, and then 100 ×.
Evaluation was carried out after conducting the test for 500 hours on a 50 × 1 mm plate. The rust resistance rank of the examples of the present invention was set to JIS rating of 9.5 or more. Toughness is size φ7.5 mm x from JIS Z2202
The test was conducted at room temperature with a U notch having a depth of 55 mm and a depth of 1 mm, and the Charpy value at that time was used for evaluation. The rank of the Charpy value of the example of the present invention was set to 60 J / cm 2 or more. The cold workability was judged by the presence or absence of cracks during heading of a hexagonal head with a collar using a cold double header. When it was possible to process without cracking, the cold workability was evaluated as good, and when cracked, the cold workability was evaluated as poor.
【００３７】以上の試験結果を表２（１）（本発明
例）、表２（２）（比較例）に示す。各表で明らかなよ
うに、本発明例は全て上記の特性ランクを満足している
のに対し、比較例No．２５はＮｉ量（％）が低いためＤ
Ｉの値が高く焼入れ硬さ、耐銹性および靭性に劣ってい
た。比較例No．２６はＮｉ量（％）が高いため冷間加工
性が悪く、ＭＩの値が０（％）以上で焼入れ硬さに劣っ
ていた。比較例No．１５はＭｎ量が高いため耐銹性に劣
っていた。The above test results are shown in Table 2 (1) (Example of the present invention) and Table 2 (2) (Comparative example). As is clear from each table, all the examples of the present invention satisfy the above characteristic ranks, whereas the comparative examples No. No. 25 has a low Ni content (%), so D
The value of I was high and the quenching hardness, rust resistance and toughness were poor. Comparative Example No. In No. 26, the cold workability was poor because the Ni content (%) was high, and the quenching hardness was inferior when the MI value was 0 (%) or more. Comparative Example No. No. 15 had a high Mn content and was inferior in rust resistance.
【００３８】比較例No．２８はＣ量（％）が低いため硬
さに劣っていた。比較例No．２９はＣ量（％）が高く粗
大炭化物が析出し、耐銹性、靭性に劣るばかりか冷間加
工性に劣っていた。比較例No．３０はＮ量（％）が高い
ためオーステナイトの存在をＣｒ炭窒化物の生成によ
り、硬さおよび耐銹性に劣っているばかりか、ブローホ
ールを生成し製造性が悪かった。比較例No．３１はＮ量
（％）が低いため硬さに劣っていた。Comparative Example No. No. 28 was inferior in hardness because the C content (%) was low. Comparative Example No. In No. 29, the C content (%) was high, coarse carbides were precipitated, and not only rust resistance and toughness were poor but also cold workability was poor. Comparative Example No. Since No. 30 had a high N content (%), the presence of austenite was inferior in hardness and rust resistance due to the formation of Cr carbonitride, and in addition, blowholes were formed and the manufacturability was poor. Comparative Example No. No. 31 was inferior in hardness because the N content (%) was low.
【００３９】比較例No．３２はＣｒ量（％）およびＭｏ
量（％）が低いためＡＲＩの値が低く耐銹性に劣ってい
た。比較例No．３３はＭｏ量（％）が低いためＡＲＩの
値が低く耐銹性に劣っていた。比較例No．３４はＣｒ量
（％）が低いためＡＲＩの値が０（％）以上でδフェラ
イト組織が存在し耐銹性に劣っているばかりか、Ｗ１の
値が高く素材硬さが高いため冷間加工性に劣っていた。
比較例No．３５はＣｒ量（％）が高いためＤＩの値が０
（％）以上でδフェライト組織が存在し耐銹性に劣って
いるばかりか、Ｗ１の値が高く素材硬さが高いため冷間
加工性に劣っていた。比較例No．３６はＭｏ量（％）が
高いためＤＩの値が０（％）以上でδフェライト組織が
存在し耐銹性に劣っているばかりか、Ｗ１の値が高く素
材硬さが高いため冷間加工性に劣っていた。比較例No．
３７はＤＩの値が０（％）以上でδフェライト組織が存
在し耐銹性に劣っているばかりかＷ１の値が高く素材硬
さが高いため冷間加工性に劣っていた。Comparative Example No. 32 is Cr content (%) and Mo
Since the amount (%) was low, the ARI value was low and the rust resistance was poor. Comparative Example No. No. 33 had a low Mo content (%) and thus had a low ARI value and was inferior in rust resistance. Comparative Example No. No. 34 has a low Cr content (%) and thus has an ARI value of 0 (%) or more and is inferior in rust resistance due to the presence of a δ ferrite structure. In addition, it has a high W1 value and a high material hardness, so cold working I was inferior in sex.
Comparative Example No. No. 35 has a high Cr content (%), so the DI value is 0.
(%) Or more, the δ ferrite structure was present and the rust resistance was poor, and the cold workability was poor because the W1 value was high and the material hardness was high. Comparative Example No. No. 36 has a high Mo content (%) and therefore has a DI value of 0 (%) or more and is inferior in rust resistance due to the presence of a δ ferrite structure. In addition, it has a high W1 value and a high material hardness, so it is cold worked. I was inferior in sex. Comparative Example No.
In No. 37, the DI value was 0 (%) or more, the δ ferrite structure was present and the rust resistance was inferior, and the W1 value was high and the material hardness was high, so the cold workability was inferior.
【００４０】本発明例No．１６〜１８はＢ量（％）を添
加したことで本発明例No．１３に比べ硬さおよび靭性が
向上した。比較例No．３８はＢ量（％）が高いため耐銹
性および靭性に劣っていた。本発明例No．２０，２１は
Ｔｉを添加したことで、本発明例No．１９に比べ耐銹性
が向上した。本発明例No．２２はＴｉとＮｂの両方を添
加したことで、本発明例No．１９に比べ耐銹性が向上し
た。本発明例No．２３，２４はＮｂを添加したことで、
本発明例No．１９に比べ耐銹性が向上した。しかし、比
較例No．３９〜４１はＴｉ，Ｎｂ量（％）が高すぎるた
めＷ２の値が高く冷間加工性に劣っていた。以上の実施
例から分かるように本発明鋼の優位性が明らかである。Inventive Example No. In Nos. 16 to 18 of the present invention example, the B amount (%) was added. Hardness and toughness were improved as compared with No. 13. Comparative Example No. No. 38 was inferior in rust resistance and toughness because the B content (%) was high. Inventive Example No. In Nos. 20 and 21 of the present invention, Ti was added, so that the invention sample No. Rust resistance was improved as compared with 19. Inventive Example No. No. 22 of the invention example No. 22 was obtained by adding both Ti and Nb. Rust resistance was improved as compared with 19. Inventive Example No. 23 and 24 are the addition of Nb,
Inventive Example No. Rust resistance was improved as compared with 19. However, Comparative Example No. In Nos. 39 to 41, the amounts of Ti and Nb (%) were too high, so that the value of W2 was high and the cold workability was poor. As can be seen from the above examples, the superiority of the steel of the present invention is clear.
【００４１】表２（１）および（２）に冷間加工性につ
いて本発明例および比較例を比較した実施例を示す。こ
れらの実施例は表１記載の本発明鋼No．３の成分の鋼を
表３に示すように熱間線材圧延材を焼鈍なし（No．４
４）と１段目を７５０℃で１時間、２段目を６５０℃で
１時間の２段焼鈍（No．４３）又は７００℃で１０００
時間の焼鈍（No．４２）で軟化し、続いて伸線加工、通
常焼鈍を施し、その後、冷間鍛造によりヘッディング加
工を行った。Tables (1) and (2) show examples in which the examples of the present invention and the comparative examples were compared for cold workability. These examples are steel Nos. Of the present invention shown in Table 1. As shown in Table 3, the steel having the composition of No. 3 was not annealed in the hot-rolled material (No. 4
4) and 1st step at 750 ° C for 1 hour, 2nd step at 650 ° C for 1 hour 2 step annealing (No. 43) or 700 ° C at 1000
It was softened by annealing for a period of time (No. 42), followed by wire drawing and normal annealing, and then heading by cold forging.
【００４２】これらの実施例はヘッディング加工前の素
材の強度とヘッディング時の冷間加工性で評価した。素
材の強度はＪＩＳ Ｚ２２０１により引張試験により測
定した。本発明例No．４２は引張強さが９３０N/mm2 、
本発明例No．４３は９１０N/mm2 であり、冷間加工性は
良好である。それに対し比較例No．４４は引張強さが１
６００N/mm2 であり、伸線加工ができず、冷間加工性は
不良であった。以上の実施例から分かるように本発明線
材の優位性が明らかである。In these examples, the strength of the material before heading and the cold workability during heading were evaluated. The strength of the material was measured by a tensile test according to JIS Z2201. Inventive Example No. 42 has a tensile strength of 930 N / mm 2 ,
Inventive Example No. 43 is 910 N / mm 2 , and the cold workability is good. On the other hand, Comparative Example No. 44 has a tensile strength of 1
It was 600 N / mm 2 , wire drawing was not possible, and cold workability was poor. As can be seen from the above examples, the superiority of the wire of the present invention is clear.
【００４３】表４（１）および（２）にドリリングタッ
ピンねじを製造する場合の本発明例と比較例を示す。本
発明例No．４５は表１記載のNo．３の鋼を通常のステン
レス鋼線の製造工程で溶製し、熱間線材圧延した。その
後、該熱延線材を１段目を７６０℃で１時間、２段目を
６７０℃で１時間の２段焼鈍を施し、減面率２５％で伸
線加工し、７００℃で１０分の焼鈍を施し、ドリリング
タッピンねじ成形前の素線とした。その後、冷間鍛造、
圧造、転造によりドリリングタッピンねじを成形し、そ
の後、１１５０℃×１０分保持の温度域から５℃/sの冷
却速度で焼入れし、引き続き２００℃×３０分保持の温
度域で焼戻しを施した。Tables (1) and (2) show examples of the present invention and comparative examples in the case of producing a drilling tapping screw. Inventive Example No. No. 45 shown in Table 1 Steel No. 3 was melted in the usual stainless steel wire manufacturing process, and hot-rolled. Thereafter, the hot-rolled wire was subjected to a two-step annealing in which the first step was 760 ° C. for 1 hour, and the second step was 670 ° C. for 1 hour. Annealing was performed to obtain a wire before drilling tapping screw forming. Then cold forging,
A drilling tapping screw was formed by forging and rolling, then quenched at a cooling rate of 5 ° C / s from a temperature range of 1150 ° C x 10 minutes holding, and subsequently tempered in a temperature range of 200 ° C x 30 minutes holding. .
【００４４】比較例No．４６〜５１は従来のドリリング
タッピンねじの例を示す。これらの実施例のねじ成形加
工は、通常のステンレス製ドリリングタッピンねじの製
造工程でねじ成形した。成形後、ＳＵＳ４１０製の比較
例No．４６は窒化焼入れ・焼戻しを行い、その後、表層
にＮｉ−Ｃｒめっきを施した。ＳＵＳ３０４製の比較例
No．４７は表面硬化のため窒化処理を施し、比較例No．
４８は、耐銹性付与のため更にその上にダクロ処理を施
した。ＳＵＳ３０５製の比較例No．４９は表層硬化のた
めの窒化処理後、耐銹性付与のためねじ頭部のみショッ
ト・酸洗で表層の窒化層を落とした。高強度高Ｍｎオー
ステナイト系ステンレス鋼の比較例No．５０は時効処理
を施した。高強度オーステナイト系ステンレス鋼の比較
例No．５１は時効硬化処理を施し、その後、ねじ込み時
の潤滑性付与のためＺｎめっきを施した。Comparative Example No. 46-51 show examples of conventional drilling tapping screws. The screw forming process of these examples was performed by a normal stainless steel drilling tapping screw manufacturing process. After molding, a comparative example No. made of SUS410. In No. 46, nitriding quenching and tempering were performed, and then the surface layer was plated with Ni—Cr. Comparative example made of SUS304
No. No. 47 was subjected to nitriding treatment for surface hardening, and Comparative Example No.
No. 48 was further subjected to a dacro treatment for imparting rust resistance. Comparative example No. made of SUS305. In No. 49, after the nitriding treatment for hardening the surface layer, only the screw head was shot / pickled to remove the nitrided surface layer in order to impart rust resistance. High-strength, high-Mn austenitic stainless steel comparative example No. 50 was aged. Comparative example of high strength austenitic stainless steel No. No. 51 was age-hardened, and then Zn-plated for lubricity at the time of screwing.
【００４５】これらの実施例の製造性はねじ成形時の冷
間加工性、工具寿命で評価した。製品特性は最終製品の
刃先硬さ、ねじ込み性、耐銹性で評価した。これら特性
値を表４（２）に示す。なお、工具寿命はヘッディング
加工時にパンチが破損することなく、１００００本以上
ヘッディング加工できた場合を良好、１００００本未満
の場合を不良とした。又、硬さはＪＩＳ Ｚ２２４４に
よりねじの刃先表面下０．１mmの位置を測定した。ねじ
込み性はＪＩＳ Ｂ１１２５に基づき５．５mm板厚のＳ
Ｓ４００鉄板にねじ込み試験し、損傷なくねじ込み可能
か否かで判断した。損傷なくねじ込み可能な場合はねじ
込み性を良好、不可な場合はねじ込み性を不良として評
価した。耐銹性評価試験はドリリングタッピンねじを発
泡スチロールに２０°傾けて差し込みＪＩＳ Ｚ２３７
１により５００時間試験実施後評価した。評価はねじ頭
が無発銹の場合を良好、点錆発銹および全面発銹の場合
を不良とした。The manufacturability of these examples was evaluated by the cold workability during screw forming and the tool life. The product characteristics were evaluated by the hardness of the cutting edge of the final product, screwability, and rust resistance. These characteristic values are shown in Table 4 (2). The tool life was evaluated as good when 10000 or more heads could be headed without damaging the punch during heading, and as poor when less than 10000. The hardness was measured according to JIS Z2244 at a position 0.1 mm below the surface of the blade edge of the screw. Screwability is based on JIS B1125 and is S of 5.5mm plate thickness.
A screwing test was performed on the S400 iron plate, and it was judged whether or not the screwing was possible without damage. If screwing was possible without damage, the screwability was evaluated as good, and if not, the screwability was evaluated as poor. For the rust resistance evaluation test, insert a drilling tapping screw into the styrofoam at an angle of 20 ° according to JIS Z237.
1 was evaluated after conducting the test for 500 hours. The evaluation was good when the screw head had no rust, and bad when the point rust was rusted and the entire surface was rusted.
【００４６】表４（２）から明らかなように、本発明例
は製造性および製品特性とも全て良好であった。一方、
比較例No．４６のＳＵＳ４１０の窒化焼入れ材は耐銹性
に劣っていた。又、比較例No．４７のＳＵＳ３０４の表
面窒化処理材は耐銹性に劣っていた。比較例No．４８の
ＳＵＳ３０４の表面窒化処理およびダクロ処理材はコス
トが高いばかりか耐銹性に劣っていた。比較例No．４９
のＳＵＳ３０５の表面窒化処理および頭部ショット、酸
洗処理材はコストが高いばかりか表面窒化処理層が完全
に除去できないため耐銹性に劣っていた。比較例No．５
０の高Ｍｎ高強度オーステナイト系ステンレス鋼の時効
処理材は、高加工硬化・高強度のため冷間加工性および
工具寿命に劣っているばかりか、加工割れ部から発銹し
耐銹性に劣っていた。比較例No．５１の高強度オーステ
ナイト系ステンレス鋼の時効処理およびＺｎめっき材は
高加工硬化・高強度のため冷間加工性および工具寿命に
劣っているばかりか、Ｚｎめっきが全面発銹し、耐銹性
に劣っていた。以上の実施例から分かるように本発明の
ドリリングタッピンねじの優位性が明らかである。As is clear from Table 4 (2), the examples of the present invention were good in both manufacturability and product characteristics. on the other hand,
Comparative Example No. The SUS410 nitriding hardened material of No. 46 was inferior in rust resistance. In addition, Comparative Example No. The surface nitriding material of No. 47 SUS304 was inferior in rust resistance. Comparative Example No. The surface nitriding and Dakuro treatment materials of SUS304 of 48 were not only high in cost but inferior in rust resistance. Comparative Example No. 49
The surface nitriding treatment, head shot, and pickling treatment of SUS 305 of No. 3 were not only high in cost but also inferior in rust resistance because the surface nitriding layer could not be completely removed. Comparative Example No. 5
No. 0 high-Mn high-strength austenitic stainless steel aging treated material is not only inferior in cold workability and tool life because of high work hardening and high strength, but also inferior in rust resistance due to rusting from work cracks. Was there. Comparative Example No. 51 high-strength austenitic stainless steel aging treatment and Zn plating material are not only inferior in cold workability and tool life due to high work hardening and high strength, but also Zn plating rusts on the whole surface and rust resistance It was inferior. As can be seen from the above examples, the superiority of the drilling tapping screw of the present invention is clear.
【００４７】[0047]
【表１】 [Table 1]
【００４８】[0048]
【表２】 [Table 2]
【００４９】[0049]
【表３】 [Table 3]
【００５０】[0050]
【表４】 [Table 4]
【００５１】[0051]
【表５】 [Table 5]
【００５２】[0052]
【表６】 [Table 6]
【００５３】[0053]
【表７】 [Table 7]
【００５４】[0054]
【発明の効果】以上の各実施例から明らかなように本発
明によりねじ込み性および耐銹性に優れたねじ、打ち抜
き性および耐銹性に優れた釘、耐銹性に優れた刃物およ
び耐銹性に優れた高強度ばね等を安価に提供することが
可能で、産業上有用な効果がもたらされる。As is apparent from the above examples, according to the present invention, a screw having excellent screwing property and rust resistance, a nail having excellent punching property and rust resistance, a blade having excellent rust resistance and rust resistance. It is possible to provide a high-strength spring or the like having excellent properties at a low cost, which brings industrially useful effects.
【図面の簡単な説明】[Brief description of drawings]
【図１】ドリリングタッピンねじを示す正面図。FIG. 1 is a front view showing a drilling tapping screw.
【図２】炭素鋼製ドリリングタッピンねじの使用状態を
示す斜視図。FIG. 2 is a perspective view showing a usage state of a carbon steel drilling tapping screw.
【図３】ステンレス製ねじのねじ止め状態を示す斜視
図。FIG. 3 is a perspective view showing a screwed state of a stainless steel screw.
【図４】孔食発生電位とＣｒ炭化物の平均粒径との関係
を示す図表。FIG. 4 is a chart showing the relationship between pitting corrosion generation potential and average grain size of Cr carbide.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 松井 孝至 光市大字島田3434番地 新日本製鐵株式会 社光製鐵所内 (72)発明者 吉村 公一 光市大字島田3434番地 新日本製鐵株式会 社光製鐵所内 (72)発明者 村田 亘 光市大字島田3434番地 新日本製鐵株式会 社光製鐵所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Matsui 3434 Shimada, Hikari-shi, Nippon Steel Co., Ltd. Inside the Komatsu Works (72) Inventor, Koichi Yoshimura 3434 Shimada, Koichi-shi Nippon Steel Co., Ltd. (72) Inventor Wataru Murata 3434 Shimada, Omitsu-shi, Nippon Steel Works, Ltd.
Claims (11)
２１（％）、（２）式で表されるＤＩの値が０（％）未
満、（３）式で表されるＭＩの値が０（％）未満、
（４）式のＷ１の値が２６０（％）未満で、残部が実質
的にＦｅおよび不可避的不純物からなり、かつ粒径０．
２μｍ以下（零も含む）のＣｒ炭化物が析出しているマ
ルテンサイト組織、又は、焼戻しマルテンサイト組織を
有することを特徴とする耐銹性に優れた高強度マルテン
サイト系ステンレス鋼。 ＡＲＩ＝Ｃｒ＋2.4 Ｍｏ ………（１）式 ＤＩ ＝Ｃｒ＋1.21Ｍｏ＋0.48Ｓｉ＋2.48Ａｌ −（24.5Ｃ＋18.4Ｎ＋Ｎｉ＋0.11Ｍｎ）−10.0 ………（２）式 ＭＩ ＝Ｎｉ＋30Ｃ＋0.12Ｍｎ＋18Ｎ＋0.83（Ｃｒ＋1.5 Ｓｉ＋1.4 Ｍｏ） −25.0 ………（３）式 Ｗ１ ＝24Ｍｏ＋13.3Ｃｒ＋６Ｍｎ＋６Ｓｉ＋Ｎｉ ………（４）式1. C: 0.13 to 0.20%, Si: 0.1 to 0.5% or less, Mn: 0.1 to 2.0% or less, Ni: 1.0 to 10% by weight. 2.5%, Cr: 12.0 to 16.0%, Mo: 1.3 to 3.5%, N: 0.06 to 0.13%, and represented by the formula (1). ARI value is 16 ~
21 (%), the value of DI represented by the formula (2) is less than 0 (%), the value of MI represented by the formula (3) is less than 0 (%),
The value of W1 in the equation (4) is less than 260 (%), the balance is substantially Fe and unavoidable impurities, and the grain size is 0.
A high-strength martensitic stainless steel having excellent rust resistance, which has a martensitic structure in which Cr carbides of 2 μm or less (including zero) are precipitated or a tempered martensitic structure. ARI = Cr + 2.4 Mo ... (1) Formula DI = Cr + 1.21Mo + 0.48Si + 2.48Al- (24.5C + 18.4N + Ni + 0.11Mn) -10.0 ... (2) Formula MI = Ni + 30C + 0.12Mn + 18N + 0.83 (Cr + 1. 5 Si + 1.4 Mo) −25.0 …… (3) Formula W1 = 24Mo + 13.3Cr + 6Mn + 6Si + Ni …… (4) Formula
れた高強度マルテンサイト系ステンレス鋼。2. The high-strength martensitic stainless steel excellent in rust resistance according to claim 1, characterized in that it contains B: 0.001 to 0.010% by weight.
（％）未満で残部が実質的にＦｅおよび不可避的不純物
からなることを特徴とする請求項１又は２記載の耐銹性
に優れた高強度マルテンサイト系ステンレス鋼。 Ｗ２＝24Ｍｏ＋13.3Ｃｒ＋６Ｍｎ＋６Ｓｉ＋Ｎｉ＋10Ｔｉ＋10Ｎｂ…（５）式3. A weight ratio of Ti: 0.05 to 1.0%, Nb: 0.05 to 1.0%, and a value of W2 represented by the formula (5) of 260.
The high-strength martensitic stainless steel excellent in rust resistance according to claim 1 or 2, wherein the balance is less than (%) and the balance is substantially Fe and unavoidable impurities. W2 = 24Mo + 13.3Cr + 6Mn + 6Si + Ni + 10Ti + 10Nb (5) Formula
２１（％）、（２）式で表されるＤＩの値が０（％）未
満、（３）式で表されるＭＩの値が０（％）未満、
（４）式で表されるＷ１の値が２６０（％）未満で、残
部が実質的にＦｅおよび不可避的不純物からなる鋼で、
熱間圧延によって製造された熱延線材を焼鈍して得られ
た線材の引張強度が９５０N/mm2 以下であることを特徴
とする耐銹性に優れた高強度マルテンサイト系ステンレ
ス鋼およびマルテンサイト系ステンレス鋼線材。 ＡＲＩ＝Ｃｒ＋2.4 Ｍｏ ………（１）式 ＤＩ ＝Ｃｒ＋1.21Ｍｏ＋0.48Ｓｉ＋2.48Ａｌ −（24.5Ｃ＋18.4Ｎ＋Ｎｉ＋0.11Ｍｎ）−10.0 ………（２）式 ＭＩ ＝Ｎｉ＋30Ｃ＋0.12Ｍｎ＋18Ｎ＋0.83（Ｃｒ＋1.5 Ｓｉ＋1.4 Ｍｏ） −25.0 ………（３）式 Ｗ１ ＝24Ｍｏ＋13.3Ｃｒ＋６Ｍｎ＋６Ｓｉ＋Ｎｉ ………（４）式4. By weight%, C: 0.13 to 0.20%, Si: 0.1 to 0.5% or less, Mn: 0.1 to 2.0% or less, Ni: 1.0 to 2.5%, Cr: 12.0 to 16.0%, Mo: 1.3 to 3.5%, N: 0.06 to 0.13%, and represented by the formula (1). ARI value is 16 ~
21 (%), the value of DI represented by the formula (2) is less than 0 (%), the value of MI represented by the formula (3) is less than 0 (%),
A steel in which the value of W1 represented by the formula (4) is less than 260 (%) and the balance substantially consists of Fe and inevitable impurities,
A high-strength martensitic stainless steel and martensite having excellent rust resistance, characterized in that the wire rod obtained by annealing a hot-rolled wire rod manufactured by hot rolling has a tensile strength of 950 N / mm 2 or less. System stainless steel wire rod. ARI = Cr + 2.4 Mo ... (1) Formula DI = Cr + 1.21Mo + 0.48Si + 2.48Al- (24.5C + 18.4N + Ni + 0.11Mn) -10.0 ... (2) Formula MI = Ni + 30C + 0.12Mn + 18N + 0.83 (Cr + 1. 5 Si + 1.4 Mo) −25.0 …… (3) Formula W1 = 24Mo + 13.3Cr + 6Mn + 6Si + Ni …… (4) Formula
れた高強度マルテンサイト系ステンレス線材。5. The high-strength martensite stainless steel wire rod having excellent rust resistance according to claim 4, characterized in that B: 0.001 to 0.010% by weight is contained.
（％）未満で残部が実質的にＦｅおよび不可避的不純物
からなることを特徴とする請求項４又は５記載の耐銹性
に優れた高強度マルテンサイト系ステンレス鋼線材。 Ｗ２＝24Ｍｏ＋13.3Ｃｒ＋６Ｍｎ＋６Ｓｉ＋Ｎｉ＋10Ｔｉ＋10Ｎｂ…（５）式6. The content of Ti: 0.05 to 1.0% and Nb: 0.05 to 1.0% by weight, and the value of W2 represented by the formula (5) is 260.
The high-strength martensitic stainless steel wire rod having excellent rust resistance according to claim 4 or 5, wherein the balance is less than (%) and the balance is substantially Fe and inevitable impurities. W2 = 24Mo + 13.3Cr + 6Mn + 6Si + Ni + 10Ti + 10Nb (5) Formula
〜５０時間保定し、１００℃以下まで冷却する１回目の
焼鈍と、６００〜７５０℃で０．５〜５０時間保定後冷
却する２回目の焼鈍を施す２段焼鈍であることを特徴と
する請求項４〜６のいずれかに記載の耐銹性に優れた高
強度マルテンサイト系ステンレス鋼線材。7. The annealing is performed at 700 to 800 ° C. for 0.5.
It is a two-stage annealing in which the first annealing is carried out for 50 to 50 hours and is cooled to 100 ° C. or less, and the second annealing is carried out after being held at 600 to 750 ° C. for 0.5 to 50 hours and then cooled. Item 7. A high-strength martensitic stainless steel wire rod having excellent rust resistance according to any one of Items 4 to 6.
２１（％）、（２）式で表されるＤＩの値が０（％）未
満、（３）式で表されるＭＩの値が０（％）未満、
（４）式で表されるＷ１の値が２６０（％）未満で、残
部が実質的にＦｅおよび不可避的不純物からなり、刃先
硬さがＨｖで５００以上であることを特徴とする耐銹性
に優れた高強度マルテンサイト系ステンレス鋼ドリリン
グタッピンねじ。 ＡＲＩ＝Ｃｒ＋2.4 Ｍｏ ………（１）式 ＤＩ ＝Ｃｒ＋1.21Ｍｏ＋0.48Ｓｉ＋2.48Ａｌ −（24.5Ｃ＋18.4Ｎ＋Ｎｉ＋0.11Ｍｎ）−10.0 ………（２）式 ＭＩ ＝Ｎｉ＋30Ｃ＋0.12Ｍｎ＋18Ｎ＋0.83（Ｃｒ＋1.5 Ｓｉ＋1.4 Ｍｏ） −25.0 ………（３）式 Ｗ１ ＝24Ｍｏ＋13.3Ｃｒ＋６Ｍｎ＋６Ｓｉ＋Ｎｉ ………（４）式8. By weight%, C: 0.13 to 0.20%, Si: 0.1 to 0.5% or less, Mn: 0.1 to 2.0% or less, Ni: 1.0 to 2.5%, Cr: 12.0 to 16.0%, Mo: 1.3 to 3.5%, N: 0.06 to 0.13%, and represented by the formula (1). ARI value is 16 ~
21 (%), the value of DI represented by the formula (2) is less than 0 (%), the value of MI represented by the formula (3) is less than 0 (%),
The rust resistance is characterized in that the value of W1 represented by the formula (4) is less than 260 (%), the balance substantially consists of Fe and unavoidable impurities, and the cutting edge hardness is 500 or more in Hv. Excellent high strength martensitic stainless steel drilling tapping screw. ARI = Cr + 2.4 Mo ... (1) Formula DI = Cr + 1.21Mo + 0.48Si + 2.48Al- (24.5C + 18.4N + Ni + 0.11Mn) -10.0 ... (2) Formula MI = Ni + 30C + 0.12Mn + 18N + 0.83 (Cr + 1. 5 Si + 1.4 Mo) −25.0 …… (3) Formula W1 = 24Mo + 13.3Cr + 6Mn + 6Si + Ni …… (4) Formula
２１（％）、（２）式で表されるＤＩの値が０（％）未
満、（３）式で表されるＭＩの値が０（％）未満、
（４）式で表されるＷ１の値が２６０（％）未満で、残
部が実質的にＦｅおよび不可避的不純物からなり、熱間
圧延によって得られた熱延線材を焼鈍し、伸線加工し、
焼鈍した後、ドリリングタッピンねじを冷間成形し、そ
の後１０５０〜１３００℃の温度範囲で加熱してから
０．５〜２０℃/secの冷却速度で焼入れし、焼戻し処理
を施して得られた刃先の硬さがＨｖで５００以上である
ことを特徴とする耐銹性に優れた高強度マルテンサイト
系ステンレス鋼ドリリングタッピンねじ。 ＡＲＩ＝Ｃｒ＋2.4 Ｍｏ ………（１）式 ＤＩ ＝Ｃｒ＋1.21Ｍｏ＋0.48Ｓｉ＋2.48Ａｌ −（24.5Ｃ＋18.4Ｎ＋Ｎｉ＋0.11Ｍｎ）−10.0 ………（２）式 ＭＩ ＝Ｎｉ＋30Ｃ＋0.12Ｍｎ＋18Ｎ＋0.83（Ｃｒ＋1.5 Ｓｉ＋1.4 Ｍｏ） −25.0 ………（３）式 Ｗ１ ＝24Ｍｏ＋13.3Ｃｒ＋６Ｍｎ＋６Ｓｉ＋Ｎｉ ………（４）式9. By weight%, C: 0.13 to 0.20%, Si: 0.1 to 0.5% or less, Mn: 0.1 to 2.0% or less, Ni: 1.0 to 2.5%, Cr: 12.0 to 16.0%, Mo: 1.3 to 3.5%, N: 0.06 to 0.13%, and represented by the formula (1). ARI value is 16 ~
21 (%), the value of DI represented by the formula (2) is less than 0 (%), the value of MI represented by the formula (3) is less than 0 (%),
The value of W1 represented by the formula (4) is less than 260 (%), the balance substantially consists of Fe and unavoidable impurities, and the hot-rolled wire obtained by hot rolling is annealed and drawn. ,
After annealing, a drilling tapping screw is cold-formed, then heated in a temperature range of 1050 to 1300 ° C, quenched at a cooling rate of 0.5 to 20 ° C / sec, and then subjected to a tempering treatment to obtain a cutting edge. A high-strength martensitic stainless steel drilling tapping screw with excellent rust resistance, which has a hardness of 500 or more in Hv. ARI = Cr + 2.4 Mo ... (1) Formula DI = Cr + 1.21Mo + 0.48Si + 2.48Al- (24.5C + 18.4N + Ni + 0.11Mn) -10.0 ... (2) Formula MI = Ni + 30C + 0.12Mn + 18N + 0.83 (Cr + 1. 5 Si + 1.4 Mo) −25.0 …… (3) Formula W1 = 24Mo + 13.3Cr + 6Mn + 6Si + Ni …… (4) Formula
れた高強度マルテンサイト系ステンレス鋼ドリリングタ
ッピンねじ。10. The high-strength martensitic stainless steel drilling tapping screw with excellent rust resistance according to claim 8, characterized in that it contains B: 0.001 to 0.010% by weight.
（％）未満で残部が実質的にＦｅおよび不可避的不純物
からなることを特徴とする請求項８〜１０記載の耐銹性
に優れた高強度マルテンサイト系ステンレス鋼ドリリン
グタッピンねじ。 Ｗ２＝24Ｍｏ＋13.3Ｃｒ＋６Ｍｎ＋６Ｓｉ＋Ｎｉ＋10Ｔｉ＋10Ｎｂ…（５）式11. The content of Ti: 0.05 to 1.0% and Nb: 0.05 to 1.0% by weight, and the value of W2 represented by the formula (5) is 260.
The high-strength martensitic stainless steel drilling tapping screw with excellent rust resistance according to claim 8, wherein the balance is less than (%) and the balance is substantially Fe and unavoidable impurities. W2 = 24Mo + 13.3Cr + 6Mn + 6Si + Ni + 10Ti + 10Nb (5) Formula
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP00161194A JP3340225B2 (en) | 1993-01-12 | 1994-01-12 | High strength martensitic stainless steel with excellent rust resistance and drilling tapping screw |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5-3442 | 1993-01-12 | ||
| JP344293 | 1993-01-12 | ||
| JP00161194A JP3340225B2 (en) | 1993-01-12 | 1994-01-12 | High strength martensitic stainless steel with excellent rust resistance and drilling tapping screw |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06264194A true JPH06264194A (en) | 1994-09-20 |
| JP3340225B2 JP3340225B2 (en) | 2002-11-05 |
Family
ID=26334864
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP00161194A Expired - Lifetime JP3340225B2 (en) | 1993-01-12 | 1994-01-12 | High strength martensitic stainless steel with excellent rust resistance and drilling tapping screw |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3340225B2 (en) |
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| JP6821097B1 (en) | 2019-12-19 | 2021-01-27 | 日鉄ステンレス株式会社 | Martensitic stainless steel for high hardness and corrosion resistance with excellent cold workability and its manufacturing method |
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| US5714114A (en) * | 1995-01-13 | 1998-02-03 | Hitachi Metals, Ltd. | High hardness martensitic stainless steel with good pitting corrosion resistance |
| JPH1036945A (en) * | 1996-07-19 | 1998-02-10 | Nippon Steel Corp | High rust resistant drilling trapping screw made of martensitic stainless steel excellent in screwing property and method for quenching the same |
| JP2000230527A (en) * | 1999-01-13 | 2000-08-22 | Illinois Tool Works Inc <Itw> | Selectively quenched carbon steel screw |
| WO2000049190A1 (en) * | 1999-02-18 | 2000-08-24 | Nippon Steel Corporation | High-strength, high-toughness stainless steel excellent in resistance to delayed fracture |
| JP2000239803A (en) * | 1999-02-18 | 2000-09-05 | Nippon Steel Corp | Stainless steel with high strength and high toughness, excellent in delayed fracture resistance |
| US6679954B1 (en) | 1999-02-18 | 2004-01-20 | Nippon Steel Corporation | High-strength, high-toughness stainless steel excellent in resistance to delayed fracture |
| CN100348875C (en) * | 2002-07-04 | 2007-11-14 | 有限会社新城制作所 | Heat resistant drill screw |
| WO2004005732A1 (en) * | 2002-07-04 | 2004-01-15 | Shinjo Mfg. Co., Ltd. | Heat resistant drill screw |
| JP2004156126A (en) * | 2002-11-08 | 2004-06-03 | Nippon Steel Corp | High corrosion resistant austenitic stainless steel with excellent cold workability |
| JP2006057729A (en) * | 2004-08-20 | 2006-03-02 | Taisei Corp | Lumber joining screw member and lumber joining structure using it |
| JP2006183081A (en) * | 2004-12-27 | 2006-07-13 | Nippon Steel & Sumikin Stainless Steel Corp | WEAR RESISTANT Cr BASED STAINLESS STEEL WIRE ROD OR STEEL WIRE HAVING EXCELLENT CORROSION RESISTANCE AND COLD WORKABILITY, AND MATERIAL FOR LOOM REED USING THE STEEL WIRE |
| JP4624774B2 (en) * | 2004-12-27 | 2011-02-02 | 新日鐵住金ステンレス株式会社 | Cr-based stainless steel wire rod for wear resistance excellent in corrosion resistance and cold workability, or lead wire for loom cages using the steel wire |
| JP2020519757A (en) * | 2017-06-26 | 2020-07-02 | ヒルティ アクチエンゲゼルシャフト | Martensitic hardenable steel and its use, especially screw manufacturing |
| CN111742067A (en) * | 2018-03-08 | 2020-10-02 | 喜利得股份公司 | Bimetallic screw with martensitic hardenable steel |
| CN115667569A (en) * | 2020-03-20 | 2023-01-31 | 株式会社Posco | Highly corrosion-resistant martensitic stainless steel and method for producing same |
| CN113549742A (en) * | 2021-07-23 | 2021-10-26 | 攀钢集团江油长城特殊钢有限公司 | Annealing method of 3Cr17NiMo electroslag ingot |
| CN113549742B (en) * | 2021-07-23 | 2023-06-16 | 攀钢集团江油长城特殊钢有限公司 | Annealing method of 3Cr17NiMo electroslag ingot |
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