JPH054565Y2 - - Google Patents
Info
- Publication number
- JPH054565Y2 JPH054565Y2 JP1985133478U JP13347885U JPH054565Y2 JP H054565 Y2 JPH054565 Y2 JP H054565Y2 JP 1985133478 U JP1985133478 U JP 1985133478U JP 13347885 U JP13347885 U JP 13347885U JP H054565 Y2 JPH054565 Y2 JP H054565Y2
- Authority
- JP
- Japan
- Prior art keywords
- hardened layer
- screw
- hardness
- drill
- stainless steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000010079 rubber tapping Methods 0.000 claims description 18
- 238000005121 nitriding Methods 0.000 claims description 13
- 229910000963 austenitic stainless steel Inorganic materials 0.000 claims description 12
- 238000005553 drilling Methods 0.000 description 8
- 238000000034 method Methods 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 238000007747 plating Methods 0.000 description 4
- 238000005256 carbonitriding Methods 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 229910001096 P alloy Inorganic materials 0.000 description 2
- 238000005255 carburizing Methods 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- OFNHPGDEEMZPFG-UHFFFAOYSA-N phosphanylidynenickel Chemical compound [P].[Ni] OFNHPGDEEMZPFG-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Landscapes
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Heat Treatment Of Articles (AREA)
Description
〈産業上の利用分野〉
本考案は、オーステナイト系ステンレス鋼製の
ねじ、特にセルフタツピング機能又はセルフタツ
ピング・ドリリング機能を有するねじの改良に関
する。
〈従来の技術〉
オーステナイト系ステンレス鋼のねじは、屋外
でも長期間錆が発生しない性質を有する。ところ
が、オーステナイト系ステンレス鋼は焼入れによ
り硬化しないため、実開昭60−75461号公報に記
載された考案においては、無電解ニツケルメツキ
法により、オーステナイト系ステンレス鋼製タツ
ピングねじの表面に、ニツケル燐合金の皮膜をコ
ーテイングすることにより、当該タツピングねじ
の硬度を高めることが提案されている。
〈考案が解決しようとする問題点〉
ところが、メツキによつてニツケル燐合金の皮
膜をねじの表面に形成した場合、メツキ不良等に
より、その皮膜が剥離するおそれがある。
また、先端部にドリル部を有するセルフタツピ
ングねじにおいては、ドリル部の硬度が通常のタ
ツピングねじより高い方が望ましい。ところが無
電解ニツケルメツキ法によれば、ビツカース硬度
HV550までにしかならず、それ以上硬化させる
ためには、光輝焼鈍が必要となり、加工々程が増
えてしまう。さらに、硬度を上げると、割れ、カ
ケの生ずるおそれが有る。
一方、金属表面に窒化による硬化層を形成して
金属表面を硬化する方法は、例えば昭和52年12月
25日、日刊工業新聞社発行の「金属表面技術便
覧」に開示されているように従来から知られてい
る。
この方法によつて得られる硬化層は、その硬さ
をビツカース硬度HVで1000以上に高めることが
できる等の利点を有する。このため、現在では
種々のものに広く利用されている。
しかしながら、先端にドリル部を備えて綱板に
もねじ自ら下孔を開け、タツピングを行うタツピ
ングねじにおいては、綱板に下孔を開ける際ドリ
ル部に衝撃力がかかる。このため、この種のねじ
表面に窒化による硬化層を形成した場合、使用の
際に硬化層にカケを生じることがある。特に、下
孔を開ける際には連続的に衝撃力がかかるため、
極わずかのカケが発生した場合にもそのカケ部か
ら伝播して全体にカケが生じてしまうことにな
る。
従つて、先端部にドリル部を有するタツピング
ねじに窒化による硬化層の形成は適応させ難いと
されている。
本考案は、このような実情に鑑み提案されたも
のでその目的とするところは使用に際しカケの生
じない窒化による硬化層を有するオーステナイト
系ステンレス綱製のタツピングねじを提供するこ
とにある。
〈課題を解決するための手段〉
本考案は以下の特徴を有するオーステナイト系
ステンレス綱製のタツピングねじを提供すること
により上記課題を解決する。
本考案のタツピングねじの軸部は、下端先端部
に形成されねじの下孔を開けるドリル部と、この
ドリル部と頭部間に形成されるねじ部とを有して
なる。
又、少なくともドリル部は、その表面に窒化処
理によつて形成された硬化層を備える。そして、
この硬化層の表面硬さはビツカース硬度HV600
〜1100であり、且つ、硬化層の表面からビツカー
ス硬度HV420までの深さは10μ〜70μである。
〈作用〉
本考案においては、少なくともドリル部表面に
窒化処理によつてビツカース硬度HV600〜1100
の表面硬さを有する硬化層を備えるため、ドリル
部によつてねじの下孔を開ける際の硬化層の剥離
を防止することができるとともに、綱板等の下孔
を開けるに十分な硬さとするすることができる。
又、硬化層の表面からビツカース硬度HV420
までの深さを10μ〜70μとすることにより、下孔
を開ける際にドリル部に連続的に衝撃力がかかつ
た場合にも硬化層のカケの発生を防止することが
でき、円滑に下孔を開けることができる。
〈第１の実施例〉
第１図は第１の実施例のねじを示すもので、こ
のねじは、軸部１と頭部２とを有し、軸部１の先
端には、ドリル部３が形成され、ドリル部３と頭
部２との間には、タツピング及び締付作用を行う
ねじ部４が形成されている。頭部２には、ドライ
バー等の締付工具を受容する十字穴５が、設けら
れている。そして、ねじの全表面に硬化層６が形
成されている。
本考案のねじにはオーステナイト系ステンレス
綱を加工するものであるが、この実施例では
18Cr−8Niに銅を添加して冷間加工硬化性を低く
抑えたものを用いた。その化学成分及び機械的性
質を次の表１に示す。
<Industrial Application Field> The present invention relates to an improvement of an austenitic stainless steel screw, particularly a screw having a self-tapping function or a self-tapping/drilling function. <Prior Art> Austenitic stainless steel screws have the property of not rusting for a long time even outdoors. However, since austenitic stainless steel cannot be hardened by quenching, the invention described in Japanese Utility Model Application Publication No. 1987-75461 uses a nickel-phosphorus alloy on the surface of an austenitic stainless steel tapping screw using the electroless nickel plating method. It has been proposed to increase the hardness of the tapping screw by coating it with a film. <Problems to be Solved by the Invention> However, when a nickel-phosphorus alloy film is formed on the surface of a screw by plating, there is a risk that the film may peel off due to poor plating or the like. Further, in a self-tapping screw having a drilled portion at the tip, it is desirable that the hardness of the drilled portion is higher than that of a normal tapping screw. However, according to the electroless Nickelmecki method, the Vickers hardness
It can only be hardened to HV550, and in order to harden it further, bright annealing is required, which increases the number of processing steps. Furthermore, increasing the hardness may cause cracks and chips. On the other hand, a method of hardening the metal surface by forming a hardened layer on the metal surface by nitriding, for example,
It has been known for a long time as disclosed in "Metal Surface Technology Handbook" published by Nikkan Kogyo Shimbun on the 25th. The hardened layer obtained by this method has the advantage that its hardness can be increased to 1000 or more on the Vickers hardness HV. For this reason, it is now widely used for various purposes. However, in a tapping screw that is equipped with a drill portion at the tip and performs tapping by drilling a pilot hole in the steel plate itself, an impact force is applied to the drill portion when drilling the pilot hole in the steel plate. Therefore, if a hardened layer is formed by nitriding on the surface of this type of screw, the hardened layer may chip during use. In particular, when drilling a pilot hole, continuous impact force is applied, so
Even if a very small chip occurs, it will propagate from that chip and cause chips to occur throughout. Therefore, it is difficult to apply the formation of a hardened layer by nitriding to a tapping screw having a drilled portion at the tip. The present invention was proposed in view of the above circumstances, and its purpose is to provide a tapping screw made of austenitic stainless steel having a hardened layer by nitridation that does not cause chipping during use. <Means for Solving the Problems> The present invention solves the above problems by providing a tapping screw made of austenitic stainless steel having the following characteristics. The shaft portion of the tapping screw of the present invention has a drill portion formed at the tip of the lower end to drill a pilot hole for the screw, and a threaded portion formed between the drill portion and the head. Further, at least the drill portion includes a hardened layer formed by nitriding on its surface. and,
The surface hardness of this hardened layer is Bitkers hardness HV600.
-1100, and the depth from the surface of the hardened layer to the Vickers hardness HV420 is 10μ to 70μ. <Function> In the present invention, at least the surface of the drill part is nitrided to have a Bitkers hardness of HV600 to 1100.
Since the hardened layer has a surface hardness of can be done. In addition, the hardness of the hardened layer is HV420.
By setting the depth to 10μ to 70μ, it is possible to prevent the occurrence of chipping of the hardened layer even if impact force is continuously applied to the drill part when drilling the pilot hole, and the bottom hole can be smoothly lowered. Can make holes. <First Embodiment> FIG. 1 shows a screw according to the first embodiment. This screw has a shaft portion 1 and a head 2, and a drill portion 3 is attached to the tip of the shaft portion A threaded portion 4 for tapping and tightening is formed between the drill portion 3 and the head 2. The head 2 is provided with a cross recess 5 for receiving a tightening tool such as a screwdriver. A hardened layer 6 is formed on the entire surface of the screw. The screw of the present invention is made of austenitic stainless steel, but in this example,
18Cr-8Ni with copper added to suppress cold work hardenability was used. Its chemical composition and mechanical properties are shown in Table 1 below.
【表】
このねじは、上記綱線にヘツダ加工を施し頭部
２を形成し、ダイスによりドリル部３を加工し、
ローリングダイスによりねじ部４の加工を施した
ものである。これら冷間加工により、ねじは第２
図に示すように、中心線に沿う断面において、ね
じ部４でビツカース硬度HV180〜280、頭部３及
びドリル部２でHV300〜360にまで硬化する。
次に、ねじの全表面に硬化層６を形成するた
め、窒化処理を行う。この窒化処理の方法とし
て、当該実施例では、硬度を増大させるため浸炭
処理を併用した真空浸炭窒化処理を行なう。第３
図は、第１図におけるねじ部４の断面組織を示す
もので、均一な硬化層が得られている。この硬化
層の表面の硬さは、ビツカース硬度HV1050に達
し、硬化層の形成されない内部の硬さは、
HV265であつた。そして表面からビツカース硬
度HV420までの深さを硬化層の厚さとすると、
該厚さは110μであつた。
以上、この実施例では、真空浸炭窒化により硬
化層を形成したものであるが、硬化層の厚みが大
きい結果、ねじの取扱中等にねじ同士がぶつか
り、カケが生じる場合が有る。
〈第２の実施例〉
第２の実施例のねじは第１の実施例のねじと同
様の形状を有する。このねじは、第１の実施例と
同様のオーステナイト系ステンレス綱線を加工
し、真空浸炭法と組合せた窒化処理を施した後、
焼なましを行なつたものであり、表面の硬さがビ
ツカース硬度HV600〜1000の硬化層を形成する
（第４図参照）。この硬化層の厚みは50μであつ
た。
〈第３の実施例〉
次に、第３の実施例を説明するに、この実施例
では第１の実施例と同様のねじに、融液のシアン
ソーダ中にて浸炭窒化を行なうシアナイジング法
により硬化層を形成した。第５図は、ねじ部の断
面組織を示すもので、15μの硬化層が得られてい
る。この硬化層の硬さは、ビツカース硬度
HV960〜970であつた。
〈各実施例の試験結果〉
叙上の第１乃至第３の各実施例の特性を下記の
表２に示す。[Table] This screw is made by applying a header to the above-mentioned wire to form the head 2, and then processing the drill part 3 with a die.
The threaded portion 4 is processed using a rolling die. Through these cold workings, the screw becomes
As shown in the figure, in the cross section along the center line, the screw portion 4 is hardened to a Vickers hardness of HV 180 to 280, and the head 3 and drill portion 2 are hardened to HV 300 to 360. Next, a nitriding treatment is performed to form a hardened layer 6 on the entire surface of the screw. As a method for this nitriding treatment, in this embodiment, vacuum carbonitriding treatment is performed in combination with carburizing treatment in order to increase hardness. Third
The figure shows the cross-sectional structure of the threaded portion 4 in FIG. 1, and a uniform hardened layer is obtained. The hardness of the surface of this hardened layer reaches Bitkers hardness HV1050, and the hardness of the inside where the hardened layer is not formed is:
It was HV265. Then, if the depth from the surface to Bitkers hardness HV420 is the thickness of the hardened layer,
The thickness was 110μ. As described above, in this example, the hardened layer is formed by vacuum carbonitriding, but as a result of the large thickness of the hardened layer, the screws may collide with each other during handling, resulting in chipping. <Second Example> The screw of the second example has a similar shape to the screw of the first example. This screw was made by processing the same austenitic stainless steel wire as in the first embodiment, and then applying nitriding treatment in combination with vacuum carburizing.
It has been annealed and forms a hardened layer with a surface hardness of HV600 to HV1000 (see Fig. 4). The thickness of this hardened layer was 50μ. <Third Example> Next, a third example will be described. In this example, a screw similar to that of the first example was subjected to a cyanizing method in which carbonitriding was performed in cyan soda melt. A hardened layer was formed. FIG. 5 shows the cross-sectional structure of the threaded portion, and a hardened layer of 15μ has been obtained. The hardness of this hardened layer is the Bitkers hardness
HV was 960-970. <Test results of each example> Characteristics of each of the first to third examples described above are shown in Table 2 below.
【表】
又、各実施例のねじを、厚さ１，６mmのアルミ板
及び厚さ０，８mmの綱板に対して電動ドライバー
によりねじ込んだ試験結果を表３に示す。尚、表
３中においてNG数とはねじ込みが完全に行なわ
れなかつたものを示す。
尚、第１の実施例において、NGとなつたもの
を観察するに、頭部２の十字穴５やドリル部３に
硬加層の厚みに起因するカケが生じていた。
〈考案の効果〉
以上、本考案のオーステナイト系ステンレス綱
製のねじにおいては、メツキ等により硬化層Table 3 also shows the test results in which the screws of each example were screwed into an aluminum plate with a thickness of 1.6 mm and a steel plate with a thickness of 0.8 mm using an electric screwdriver. Incidentally, in Table 3, the NG number indicates that the screw was not completely screwed in. In addition, in the first example, it was observed that the cross recess 5 of the head 2 and the drill part 3 had chips due to the thickness of the hardening layer. <Effects of the invention> As described above, in the screw made of austenitic stainless steel of the invention, the hardened layer is formed by plating etc.
【表】
をねじの表面にコーテイングするのではなく、窒
化処理による硬化層をねじに形成するものであ
り、硬化層が剥離するおそれがない。その結果、
綱板等に対しても良好なタツピング、ドリリング
を行ない得るオーステナイト系ステンレス綱製の
ねじを提供し得たものである。
特に、硬化層の表面の硬さを、ビツカース硬度
HV600以上にすることにより、先端にドリル部
を有するセルフドリリング、タツピングねじと
し、綱板にもねじ自身により下孔を開け、タツピ
ングを行い得るねじを提供し得たものである。さ
らに、硬化層の表面からビツカース硬度HV420
までの深さを10μ〜70μとすることにより、硬化
層の表面の硬度をHV1000前後にまで高めてもカ
ケの生じにくいねじを提供し得たものである。[Table] Rather than coating the surface of the screw, a hardened layer is formed on the screw by nitriding, so there is no risk of the hardened layer peeling off. the result,
It is possible to provide a screw made of austenitic stainless steel that can perform good tapping and drilling even on steel plates and the like. In particular, the hardness of the surface of the hardened layer is measured by the Bitkers hardness.
By making the screw HV600 or higher, it is possible to provide a self-drilling, tapping screw with a drill portion at the tip, and a screw that can perform tapping by drilling a pilot hole in the steel plate itself. In addition, the surface of the hardened layer has a Vickers hardness of HV420.
By setting the depth to 10μ to 70μ, it was possible to provide a screw that does not easily chip even if the surface hardness of the hardened layer is increased to around HV1000.
第１図は各実施例のねじの側面図、第２図は窒
化処理前のねじの硬度を示す説明図、第３図はね
じ部の窒化処理による硬化層の金属組織の顕微鏡
写真、第４図は第２の実施例のねじ部の窒化処理
による硬化層の金属組織の顕微鏡写真、第５図は
第３の実施例のねじ部の窒化処理による硬化層の
金属組織の顕微鏡写真である。
１……軸部、２……頭部、３……ドリル部、４
……ねじ部、５……十字穴、１６……硬化層。
Fig. 1 is a side view of the screw of each example, Fig. 2 is an explanatory diagram showing the hardness of the thread before nitriding, Fig. 3 is a micrograph of the metal structure of the hardened layer of the thread part due to nitriding, and Fig. 4 The figure is a microscopic photograph of the metal structure of the hardened layer obtained by nitriding the threaded portion of the second embodiment, and FIG. 5 is a microscopic photograph of the metallographic structure of the hardened layer obtained by nitriding the threaded portion of the third embodiment. 1...Shaft part, 2...Head part, 3...Drill part, 4
...Threaded portion, 5...Cross recess, 16...Hardened layer.
Claims (1)
ピングねじの軸部が、下端先端部に形成されねじ
の下孔を開けるドリル部と、このドリル部と頭部
間に形成されるねじ部とを有し、 少なくともドリル部が、その表面に窒化処理に
よつて形成された硬化層を備え、この硬化層の表
面硬さがビツカース硬度HV600〜1100であり、
且つ、硬化層の表面からビツカース硬度HV420
までの深さが10μ〜70μとされたものであること
を特徴とするオーステナイト系ステンレス鋼製の
タツピングねじ。[Claim for Utility Model Registration] The shank of a tapping screw made of austenitic stainless steel has a drill part formed at the tip of the lower end to drill a pilot hole for the screw, and a screw formed between the drill part and the head. at least the drill part has a hardened layer formed on its surface by nitriding, and the hardened layer has a surface hardness of HV600 to 1100 on the Vickers hardness;
Moreover, the hardness from the surface of the hardened layer is HV420.
An austenitic stainless steel tapping screw characterized by having a depth of 10μ to 70μ.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1985133478U JPH054565Y2 (en) | 1985-08-30 | 1985-08-30 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1985133478U JPH054565Y2 (en) | 1985-08-30 | 1985-08-30 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6240320U JPS6240320U (en) | 1987-03-10 |
| JPH054565Y2 true JPH054565Y2 (en) | 1993-02-04 |
Family
ID=31033833
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1985133478U Expired - Lifetime JPH054565Y2 (en) | 1985-08-30 | 1985-08-30 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH054565Y2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2686001B2 (en) * | 1990-07-09 | 1997-12-08 | 大同ほくさん株式会社 | Austenitic stainless hard screws |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6075461U (en) * | 1983-10-27 | 1985-05-27 | ヱトー株式会社 | Austenitic stainless steel tassel pin screw |
-
1985
- 1985-08-30 JP JP1985133478U patent/JPH054565Y2/ja not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6240320U (en) | 1987-03-10 |
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