JPH07107176B2 - Method for manufacturing coil spring with excellent dimensional stability during low temperature annealing - Google Patents
Method for manufacturing coil spring with excellent dimensional stability during low temperature annealingInfo
- Publication number
- JPH07107176B2 JPH07107176B2 JP2024131A JP2413190A JPH07107176B2 JP H07107176 B2 JPH07107176 B2 JP H07107176B2 JP 2024131 A JP2024131 A JP 2024131A JP 2413190 A JP2413190 A JP 2413190A JP H07107176 B2 JPH07107176 B2 JP H07107176B2
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- Prior art keywords
- coil spring
- wire
- steel wire
- low temperature
- outer diameter
- Prior art date
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Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、低温焼鈍時の外径寸法変化率を0.25％以下と
することができる寸法安定性に優れたコイルばねの製造
方法に関する。Description: TECHNICAL FIELD The present invention relates to a method for producing a coil spring having excellent dimensional stability, which can reduce the outer diameter dimensional change rate during low temperature annealing to 0.25% or less.
（従来技術） ばねの種類は極めて多く、その分類の仕方にも種々の方
法がある。(Prior Art) There are many types of springs, and there are various methods for classifying them.
例えば、金属ばねと非金属ばねとの材質による区分や形
状等にり区分されているが、これらの種類の中、コイル
ばねはばねの機能が確実である上に小型軽量に成形でき
る特性を有することから、産業上幅広く使用されてい
る。For example, metal springs and non-metal springs are classified according to their material, shape, etc., but among these types, coil springs have the function of a spring and have the characteristic of being compact and lightweight. Therefore, it is widely used in industry.
そして、上記コイルばねの中でも冷間成形コイルばねが
多くを占めている。Cold-formed coil springs occupy most of the above coil springs.
通常冷間成形コイルばねに使用される鋼線としては、ピ
アノ線、硬鋼線、オイルテンパー線のような焼入れ、焼
戻しを施した熱処理鋼線及びステンレス鋼線が使用され
ている。As a steel wire usually used for a cold-formed coil spring, a hardened and tempered heat-treated steel wire and a stainless steel wire such as a piano wire, a hard steel wire and an oil temper wire are used.
ピアノ線、硬鋼線は、熱間圧延された線材を950℃前後
で加熱し、オーステナイト化させた後、500℃〜550℃の
鉛浴に浸漬冷却させ、強靭な微細パーライト組織（ソル
バイト組織）を得るパテンティングと称する恒温変態処
理を施した後、酸洗、皮膜処理が施された後、超合金ダ
イスやダイヤモンドダイスを用いて常温で伸線加工を行
い、所定の線径、強度に仕上げられる。For piano wire and hard steel wire, a hot-rolled wire is heated at around 950 ° C to be austenitized and then immersed in a lead bath at 500 ° C to 550 ° C to be cooled to obtain a tough fine pearlite structure (solvite structure). After subjecting to a constant temperature transformation process called patenting, after pickling and coating treatment, wire drawing is carried out at room temperature using a superalloy die or diamond die to finish to the prescribed wire diameter and strength. To be
オイルテンパー線は、中間熱処理→酸洗、潤滑処理→冷
間伸線加工→焼入れ、焼き戻しの熱処理を施して所定の
機械的性質を付与して所定の線径、強度に仕上げられ
る。The oil tempered wire is subjected to intermediate heat treatment → pickling, lubrication treatment → cold wire drawing → quenching and tempering heat treatment to impart predetermined mechanical properties to finish it to a predetermined wire diameter and strength.
他方、ステンレス鋼線は、オーステナイト系ステンレス
鋼線の加工により生じた内部応力を除去し、加工組織を
再結晶させ、延性を回復させると共に熱間加工で析出し
た炭化物等を固溶させる固溶化熱処理を行い、酸洗、皮
膜処理が施された後、超合金ダイスやダイヤモンドダイ
スを用いて常温で伸線加工を行い、所定の線径、強度に
仕上げられる。On the other hand, a stainless steel wire is a solution heat treatment that removes internal stress generated by processing an austenitic stainless steel wire, recrystallizes the worked structure, recovers ductility, and solidifies carbides and the like precipitated by hot working. After being subjected to pickling and film treatment, wire drawing is carried out at room temperature using a superalloy die or a diamond die to finish to a predetermined wire diameter and strength.
以上の如く、上述の冷間成形コイルばねは、コイルばね
に成形された後、残留歪除去や弾性限の向上等の目的に
併せて低温焼鈍処理される。As described above, the cold-formed coil spring is formed into a coil spring and then subjected to low-temperature annealing for the purpose of removing residual strain and improving the elastic limit.
この低温焼鈍処理温度は、通常ピアノ線300〜500℃、硬
鋼線200〜250℃、オイルテンパー線300〜400℃、ステン
レス鋼線300〜400℃の温度で熱処理が施されている。The low temperature annealing treatment temperature is usually 300 to 500 ° C for piano wire, 200 to 250 ° C for hard steel wire, 300 to 400 ° C for oil tempered wire, and 300 to 400 ° C for stainless steel wire.
ところが、上述の熱処理が施された各鋼線においては、
加工の際生じた残留応力が減少する反面、永久変形が生
ずる。However, in each steel wire subjected to the above heat treatment,
While the residual stress generated during processing is reduced, permanent deformation occurs.
即ち、炭素鋼は一般的に焼なまし後収縮する性状を示
し、一方、ステンレス鋼の場合では焼なまし後伸びる性
状を示す。That is, carbon steel generally exhibits the property of contracting after annealing, while stainless steel exhibits the property of expanding after annealing.
即ち、ピアノ線、硬鋼線、オイルテンパー線はコイルば
ね成形後、低温焼鈍処理するとコイル外径が縮小（密着
高さは高くなる）する性状があり、逆にステンレス鋼線
はコイルばね成形後、低温焼鈍処理するとコイル外径が
拡幅する。（密着高さは低くなる）性状を示すことが文
献、研究論文等々によって知られている。That is, piano wire, hard steel wire, and oil tempered wire have the property that the coil outer diameter is reduced (the adhesion height is increased) when low temperature annealing is performed after coil spring molding. Conversely, stainless steel wire is coil spring molded after coil spring molding. The low-temperature annealing treatment widens the outer diameter of the coil. It is known from literatures, research papers, etc. that it exhibits the property of (adhesion height becomes low).
従って、ばね鋼線を冷間コイルばねに成形する場合に留
意しなけばならないことは、上述の変形を考慮して成形
しなければならない。Therefore, what must be noted when forming the spring steel wire into the cold coil spring must be formed in consideration of the above-mentioned deformation.
例えば、ピアノ線、硬鋼線、オイルテンパー線にあって
は仕様寸法よりコイル外径寸法を大きく、逆にステンレ
ス鋼線は仕様寸法よりコイル外径寸法を小さく設定する
必要がある。For example, for piano wire, hard steel wire and oil tempered wire, it is necessary to set the coil outer diameter dimension larger than the specification dimension, and conversely, for stainless steel wire, it is necessary to set the coil outer diameter dimension smaller than the specification dimension.
（発明が解決しようとする課題） 前述の通り、各種のばね鋼線は、冷間コイル成形加工後
における低温焼鈍処理時の変形は使用する材料によって
種々の性状を示す。(Problems to be Solved by the Invention) As described above, various spring steel wires show various properties depending on the material used during the low temperature annealing treatment after the cold coil forming process.
即ち、上述の如く、熱処理が知された各鋼線において
は、加工の際生じた残留応力が減少する反面、永久変形
が生じ、例えば、炭素鋼は焼なまし後収縮する性状があ
り、又ステンレス鋼では焼なまし後伸びる性状がある関
係上、低温焼鈍処理時にコイルばね外径寸法の縮小、拡
幅の変化現象が生ずるといってもその変化量はピッチや
ばね指数等々のばねの形状、コイルばねの成形条件、ば
ね鋼線のサイズ及びメーカー基準等によって様々に変化
し、一定していない。That is, as described above, in each steel wire for which heat treatment is known, residual stress generated during processing is reduced, but permanent deformation occurs, for example, carbon steel has a property of shrinking after annealing, and Due to the property of elongation after annealing in stainless steel, even if there is a phenomenon that the outer diameter of the coil spring is reduced or the width of the coil spring is changed during low temperature annealing, the amount of change is the pitch, spring index, etc. of the spring shape. It varies depending on the coil spring molding conditions, spring steel wire size, manufacturer's standards, etc., and is not constant.
従って、冷間コイルばねの成形メーカーでは本生産の前
にコイルばねの予備成形を行い、その後、低温焼鈍処理
をして予めコイルばねの収縮、膨張の度合いを知見し、
ばね仕様寸法の許容内に属するか否かを確認しているの
が現状である。Therefore, a cold coil spring molding maker preforms the coil spring before the main production, and then performs low temperature annealing treatment to find out the degree of contraction and expansion of the coil spring in advance,
The current situation is to confirm whether the spring specifications are within the allowable range.
ところが、このコイルばねの収縮、膨張による外径寸法
の変化度合いは、個々のコイルばねによって異なり、一
律ではない。However, the degree of change in the outer diameter dimension due to the contraction and expansion of the coil spring varies depending on the individual coil spring and is not uniform.
この為、個々のコイルばねの外径寸法の変化を厳格に調
節することは困難な状況にある。Therefore, it is difficult to strictly control the change in the outer diameter of each coil spring.
このように、コイルばね成形加工後の低温焼鈍処理時に
おいて、コイルばね外径寸法の変化が起こった場合で
は、フック角も変化し、特に、引きばねの両端のフック
の相対的な角度にバラツキが生じ、コイルばねの自動装
入組立をシステム化している成形工程ではこれが大きな
障害となっている。As described above, when the coil spring outer diameter changes during the low temperature annealing process after the coil spring forming process, the hook angle also changes, and in particular, the relative angles of the hooks at both ends of the tension spring vary. Occurs, which is a major obstacle in the molding process in which the automatic charging and assembling of the coil spring is systematized.
本発明は上述の観点に鑑みなされたものであって、その
目的とするところは、コイルばねの成形後の低温焼鈍時
における寸法変化が極少なステンレス鋼線製コイルばね
の製造方法を提供することにある。The present invention has been made in view of the above-described viewpoint, and an object thereof is to provide a method for manufacturing a stainless steel wire coil spring having a minimal dimensional change during low temperature annealing after forming the coil spring. It is in.
（課題を解決するための手段） 本発明は上述の目的を達成する為に、オーステナイト相
とフェライト相の二相を呈する二相混合組織で、かつ、
フェライト量が30〜70％であるステンレス鋼線を用い
て、冷間コイル成形した後、200〜500℃の温度範囲で焼
鈍処理してなる低温焼鈍時の寸法安定性に優れたコイル
ばねの製造方法としたものである。(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention has a two-phase mixed structure exhibiting two phases of an austenite phase and a ferrite phase, and
Manufacture of coil springs with excellent dimensional stability during low temperature annealing, which is performed by cold coil forming using a stainless steel wire with a ferrite content of 30 to 70% and then annealing in the temperature range of 200 to 500 ° C. It is a method.
（作 用） 前掲の通り、本発明は、コイルばね鋼線の成形後の低温
焼鈍時に発生する外径寸法の縮小変化は結晶組織がフェ
ライト系（体心立方格子構造）であり、膨張変化はオー
ステナイト系（面心立方格子構造）の組織状態に起因す
るとの観点に立って、種々研鑽したものであり、フェラ
イト相とオーステナイト相との二相を呈するステンレス
鋼線であれば、コイルばね外径寸法の縮小膨張の変化を
相互に抑制するとの知見に基づくものである。(Operation) As described above, according to the present invention, the reduction change of the outer diameter dimension that occurs during the low temperature annealing after forming the coil spring steel wire has a ferrite structure (body-centered cubic lattice structure) in the crystal structure, and the expansion change does not occur. From the viewpoint that it is caused by the austenite (face-centered cubic lattice structure) microstructure, various studies have been made. If the stainless steel wire has a ferrite phase and an austenite phase, the coil spring outer diameter This is based on the finding that mutual changes in the reduction and expansion of dimensions are mutually suppressed.
即ち、第２図の低温焼鈍温度とコイルばねの外径変化率
（％）との関係を考察した結果、以下の事実が判明し
た。That is, as a result of examining the relationship between the low temperature annealing temperature in FIG. 2 and the outer diameter change rate (%) of the coil spring, the following facts were found.
同図のグラフは、オーステナイト系ステンレス鋼線（SU
S 304）と、フェライト相とオーステナイト相とが50％
づつ混合した２相ステンレス鋼線のコイルばね（何ずれ
も2.6Φ、ばね指数D/d＝10）、フェライト単相のピアノ
線（3.2Φ、ばね指数D/d＝15）のコイルばねを成形し、
０〜600℃の範囲の温度において各々10分間の焼鈍処理
を施し、コイルばね外径変化率Dbを Db＝（D2−D1）/D1×100 ……（１） 但し、D1;コイルばね成形後の外径（mm） D2;焼鈍処理後の外径（mm） （１）式により求めたものである。The graph in the figure shows the austenitic stainless steel wire (SU
S 304) and 50% of ferrite and austenite phases
Molded coil springs of two-phase stainless steel wire (2.6 Φ, spring index D / d = 10) and ferrite single-phase piano wire (3.2 Φ, spring index D / d = 15) Then
Annealing treatment is performed for 10 minutes each at a temperature in the range of 0 to 600 ° C., and the coil spring outer diameter change rate Db is Db = (D 2 −D 1 ) / D 1 × 100 (1) where D 1 ; Outer diameter after coil spring forming (mm) D 2 ; Outer diameter after annealing (mm) It is calculated by the equation (1).
この結果、同グラフから明らかな如く、二相混合の結晶
組織のステンレス鋼線のコイルばねでは、焼鈍温度が20
0℃から500℃の温度範囲内において外径変化が生じてい
ない結果を示しており、他方、オーステナイト系ステン
レス鋼線（SUS 304）では、焼鈍温度が200℃以上になれ
ば外径寸法に膨張現象が起こり、又フェライト単相のピ
アノ線では同様に焼鈍温度が200℃以下になれば外径寸
法に収縮現象が起こり、従来のコイルばねと同様な性状
が見られた。As a result, as is clear from the graph, the annealing temperature of the coil spring of the stainless steel wire of the two-phase mixed crystal structure is 20
The results show that the outer diameter did not change within the temperature range of 0 to 500 ° C. On the other hand, the austenitic stainless steel wire (SUS 304) expanded to the outer diameter when the annealing temperature was 200 ° C or higher. Phenomenon occurred, and in the case of a ferrite single-phase piano wire, when the annealing temperature was 200 ° C or lower, the outer diameter contracted, and the properties similar to those of conventional coil springs were observed.
以上の結果から考察すると、結晶構造としてフェライト
相とオーステナイト相との二相混合の結晶組織のステン
レス鋼線で成形したコイルばねであれば、低温焼鈍時に
起こる外径寸法の縮小膨張の変化を相互に抑制するとの
事実が立証された。Considering from the above results, in the case of a coil spring formed by a stainless steel wire having a crystal structure of a two-phase mixture of a ferrite phase and an austenite phase as a crystal structure, a change in the reduction expansion of the outer diameter dimension that occurs during low temperature annealing is mutually affected. The fact that it will be restrained was proved.
一方、フェライト量を30〜70％の範囲とした理由は、第
３図のフェライト量（％）とコイルばねの外径変化率
（％）（上記（１）式）との関係から見い出したもので
ある。On the other hand, the reason for setting the ferrite content in the range of 30 to 70% was found from the relationship between the ferrite content (%) in Fig. 3 and the outer diameter change rate (%) of the coil spring (equation (1) above). Is.
即ち、同図のグラフは、結晶組織としてフェライト相と
オーステナイト相との二相混合の結晶組織としたコイル
ばね（2.6Φ、ばね指数D/d＝10）を成形後、焼鈍温度;3
80℃、焼鈍時間;10分の処理条件で焼鈍処理した場合に
ついて、そのフェライト量を０〜100（％）の範囲で変
化させて得たものである。That is, the graph in the same figure shows that after forming a coil spring (2.6Φ, spring index D / d = 10) having a two-phase mixed crystal structure of a ferrite phase and an austenite phase as a crystal structure, an annealing temperature; 3
This is obtained by changing the ferrite amount in the range of 0 to 100 (%) in the case where the annealing treatment is performed under the treatment conditions of 80 ° C. and annealing time of 10 minutes.
この結果、同グラフから明らかな如く、フェライト量が
30〜70（％）範囲であればコイルばねの外径変化率Db
（％）が極小となった事実が見られ、0.25％以下であっ
た。As a result, as is clear from the graph,
Coil spring outer diameter change rate Db in the range of 30 to 70 (%)
The fact that (%) was minimal was found, and was below 0.25%.
他方、フェライト量が20〜０（％）範囲の場合にはコイ
ルばねの外径変化率Db（％）が大きく、膨張現象を示し
ており、又フェライト量が70〜100（％）の範囲ではコ
イルばねの外径変化率Db（％）が大きく、縮小現象が起
こっている事実が見られた。On the other hand, when the ferrite content is in the range of 20 to 0 (%), the outer diameter change rate Db (%) of the coil spring is large, indicating an expansion phenomenon, and when the ferrite content is in the range of 70 to 100 (%). The fact that the outer diameter change rate Db (%) of the coil spring was large and the contraction phenomenon occurred was observed.
以上の実験結果から、フェライト量を30〜70（％）範囲
とすることがコイルばねの外径変化率を極小とする為に
は最適であるとの知見によるものである。From the above experimental results, it is based on the finding that setting the amount of ferrite within the range of 30 to 70 (%) is optimal for minimizing the outer diameter change rate of the coil spring.
尚、本発明方法に用いるコイルばね用鋼線は上記の結果
に基づき結晶組織化されているが、この事実はオーステ
ナイト相とフェライト相の二相を呈する混合組織である
ことゝ、これらの組織の内フェライト量が30〜70％であ
る条件が満足されゝば、コイルばね用鋼線のFe、Cr、Ni
を主成分とする成分組成は特定された組成だけでなく、
同様な成分系であれば同じ結果が得られることも判明し
た。The steel wire for coil springs used in the method of the present invention has a crystallized structure based on the above results, but this fact is a mixed structure exhibiting two phases of an austenite phase and a ferrite phase. If the condition that the content of ferrite in the steel is 30 to 70% is satisfied, Fe, Cr, Ni of steel wire for coil spring
In addition to the specified composition, the composition mainly composed of
It was also found that the same result can be obtained with similar component systems.
（実施例） 以下、本発明の実施例を第１図の工程図を参照して記述
する。(Embodiment) An embodiment of the present invention will be described below with reference to the process chart of FIG.
結晶構造組織が異なる３種のコイルばね用鋼線は次のよ
うに成形した。Three types of coil spring steel wires having different crystal structure structures were formed as follows.
ピアノ線 成分組成として、 Ｃ……0.82％、Si……0.27％、Mn……0.75％、 ｐ……0.013％、Ｓ……0.004％ の5.5Φ線径のピアノ線材をパテンティング後、酸洗、
皮膜処理の後、180m/minの速度で伸線加工を９回行い、
2.0Φ線径のピアノ線（JIS G3522 SWO−Ｂ）を成形し
た。Piano wire composition: C …… 0.82%, Si …… 0.27%, Mn …… 0.75%, p …… 0.013%, S …… 0.004% 5.5Φ wire diameter of piano wire, and then pickling ,
After film treatment, wire drawing is performed 9 times at a speed of 180 m / min,
A piano wire with a diameter of 2.0 Φ (JIS G3522 SWO-B) was molded.
但し、この時の引張強さは208kg/mm2であった。However, the tensile strength at this time was 208 kg / mm 2 .
オーステナイト系ばね用ステンレス鋼線 成分組成として、 Ｃ……0.050％、Si……0.87％、Mn……1.10％、 ｐ……0.014％、Ｓ……0.003％、Ni……9.12％、 Cr……18.8％ の4.5Φ線径の原線を1150℃で固溶化処理を行い、酸
洗、皮膜処理の後、140m/minの速度で伸線加工を８回行
い、2.0Φ線径のピアノ線（JISG 3522 SWO−Ｂ）を成形
した。Austenitic stainless steel wire for springs: C …… 0.050%, Si …… 0.87%, Mn …… 1.10%, p …… 0.014%, S …… 0.003%, Ni …… 9.12%, Cr …… A solid wire of 18.8% 4.5Φ wire diameter is subjected to solution treatment at 1150 ° C, and after pickling and coating treatment, wire drawing is performed 8 times at a speed of 140m / min, and a piano wire of 2.0Φ wire diameter ( JISG 3522 SWO-B) was molded.
但し、この時に引張強さは182kgf/mm2であった。However, at this time, the tensile strength was 182 kgf / mm 2 .
本発明の２相ステンレス鋼線 成分組成として、 Ｃ……0.04％、Si……0.5％、Mn……0.48％、 ｐ……0.014％、Ｓ……0.004％、Ni……5.3％、 Cr……23.5％、 但し、フェライト量……68％ Ｃ……0.03％、Si……0.5％、Mn……0.50％、 ｐ……0.010％、Ｓ……0.005％、Ni……8.89％、 Cr……24.0％、 但し、フェライト量……51％ Ｃ……0.04％、Si……0.48％、Mn……0.50％、 ｐ……0.012％、Ｓ……0.003％、Ni……10.01％、 Cr……25.7％、 但し、フェライト量……33％ の３種類のオーステナイト相・フェライト相の二相混合
組成のばね用ステンレス鋼線（線径６Φ）の原線を1080
℃で固用化処理を行い、酸洗、皮膜処理の後、120m/min
の速度で伸線加工を９回行い、2.0Φ線径のばね用ステ
ンレス鋼線を成形した。但し、この時の引張強さはは
157kgf/mm2、は165kgf/mm2、は171kgf/mm2であっ
た。The composition of the duplex stainless steel wire of the present invention is as follows: C ... 0.04%, Si ... 0.5%, Mn ... 0.48%, p ... 0.014%, S ... 0.004%, Ni ... 5.3%, Cr ... … 23.5%, but ferrite amount …… 68% C …… 0.03%, Si …… 0.5%, Mn …… 0.50%, p …… 0.010%, S …… 0.005%, Ni …… 8.89%, Cr… … 24.0%, but ferrite amount …… 51% C …… 0.04%, Si …… 0.48%, Mn …… 0.50%, p …… 0.012%, S …… 0.003%, Ni …… 10.01%, Cr… 25.7%, but the amount of ferrite is 33%, and the original wire of stainless steel wire for springs (wire diameter 6Φ) of three kinds of two-phase mixed composition of austenite phase and ferrite phase is 1080
120m / min after solidification treatment at ℃, pickling and film treatment
The wire drawing process was performed 9 times at the speed of, and a stainless steel wire for spring having a diameter of 2.0Φ was formed. However, the tensile strength at this time is
157 kgf / mm 2 , 165 kgf / mm 2 , and 171 kgf / mm 2 .
次に、コイル外径21mm、ばね指数D/d＝10.5、巻数７の
条件とするコイルばねに成形し、３種類の鋼線を、 ピアノ線……焼鈍温度;350℃、焼鈍時間;10分、オース
テナイト系 ステンレス鋼線……焼鈍温度;400℃、焼鈍時間;10分、 ２相ステンレス鋼線……焼鈍温度;400℃、焼鈍時間;10
分、 の条件により低温焼鈍処理を施した。Next, coil outer diameter 21mm, spring index D / d = 10.5, coil springs were formed under the conditions of 7 turns, and three types of steel wire were used: piano wire, annealing temperature; 350 ° C, annealing time; 10 minutes. , Austenitic stainless steel wire: Annealing temperature: 400 ℃, Annealing time: 10 minutes, Duplex stainless steel wire: Annealing temperature: 400 ℃, Annealing time: 10
The low temperature annealing process was performed according to the conditions described above.
低温焼鈍処理を施した後、前記（１）式により、外径変
化率Dbを求めたところ第１表の結果が得られた。After performing the low temperature annealing treatment, the outer diameter change rate Db was obtained by the above formula (1), and the results shown in Table 1 were obtained.
第１表の結果から判る通り、従来材に比較して本発明
〜の外径変化率Db（％）が極端に小さいことが理解で
きる。 As can be seen from the results in Table 1, it can be understood that the outer diameter change rates Db (%) of the present invention are extremely small as compared with the conventional materials.
（発明の効果） 本発明は、オーステナイト相とフェライト相の二相を呈
する二相混合組織で、かつ、フェライト量が30〜70％で
あるステンレス鋼線を用いて、冷間コイル成形した後、
200〜500℃の温度範囲で焼鈍処理してなるものであるか
ら、低温焼鈍による外径寸法変化率が0.25％以下とな
り、成形後の低温焼鈍処理時に起こるコイルばね外径の
変化が極小となった。(Effect of the invention) The present invention is a two-phase mixed structure exhibiting two phases of an austenite phase and a ferrite phase, and using a stainless steel wire having a ferrite content of 30 to 70%, after cold coil forming,
Since it is annealed in the temperature range of 200 to 500 ° C, the outer diameter dimensional change rate due to low temperature annealing is 0.25% or less, and the change in outer diameter of the coil spring that occurs during low temperature annealing after forming is extremely small. It was
この為、コイルばねの製作時に定量的な予測がつきがた
い低温焼鈍処理時に起こる外径変化を予め見込む必要が
なく、作業能率の向上が図れた。Therefore, it is not necessary to anticipate a change in outer diameter that occurs during low temperature annealing that is difficult to quantitatively predict when manufacturing a coil spring, and work efficiency is improved.
また、外径変化率が小さいのでばね寸法が安定し、歩留
りも向上した。Further, since the outer diameter change rate is small, the spring size is stable and the yield is improved.
第１図は本発明方法の実施例に係るコイル用ばねの成形
工程を示す説明図、第２図は低温焼鈍温度とコイルばね
の外径変化率（％）との関係を示すグラフ、第３図はフ
ェライト量（％）とコイルばねの外径変化率（％）との
関係を示すグラフである。FIG. 1 is an explanatory view showing a forming process of a coil spring according to an embodiment of the method of the present invention, FIG. 2 is a graph showing a relationship between a low temperature annealing temperature and a coil spring outer diameter change rate (%), and FIG. The figure is a graph showing the relationship between the ferrite amount (%) and the outer diameter change rate (%) of the coil spring.
Claims (1)
呈する二相混合組織で、かつ、フェライト量が30〜70％
であるステンレス鋼線を用いて、冷間コイル成形した
後、200〜500℃の温度範囲で焼鈍処理してなることを特
徴とする低温焼鈍時の寸法安定性に優れたコイルばねの
製造方法。1. A two-phase mixed structure exhibiting two phases, an austenite phase and a ferrite phase, and a ferrite content of 30 to 70%.
A method for producing a coil spring having excellent dimensional stability during low temperature annealing, which comprises performing cold coil forming using a stainless steel wire as described above and then performing annealing treatment in a temperature range of 200 to 500 ° C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2024131A JPH07107176B2 (en) | 1990-02-01 | 1990-02-01 | Method for manufacturing coil spring with excellent dimensional stability during low temperature annealing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2024131A JPH07107176B2 (en) | 1990-02-01 | 1990-02-01 | Method for manufacturing coil spring with excellent dimensional stability during low temperature annealing |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03229841A JPH03229841A (en) | 1991-10-11 |
| JPH07107176B2 true JPH07107176B2 (en) | 1995-11-15 |
Family
ID=12129758
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2024131A Expired - Lifetime JPH07107176B2 (en) | 1990-02-01 | 1990-02-01 | Method for manufacturing coil spring with excellent dimensional stability during low temperature annealing |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07107176B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0791621B2 (en) * | 1992-07-01 | 1995-10-04 | 神鋼鋼線工業株式会社 | Highly fatigue and corrosion resistant duplex stainless steel wire rope |
| JP5296955B2 (en) * | 2001-02-14 | 2013-09-25 | 日本精線株式会社 | Stainless steel thin wire for spring |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5413413A (en) * | 1977-06-30 | 1979-01-31 | Kubota Ltd | High cr low ni two-phase stainless cast steel of high corrosion resistance and high strength |
| JPS55158256A (en) * | 1979-05-29 | 1980-12-09 | Daido Steel Co Ltd | Ferritic-austenitic two-phase stainless steel |
| JPS60165361A (en) * | 1984-02-07 | 1985-08-28 | Kubota Ltd | Highly corrosion resistant and high yield strength two- phase stainless steel |
| JPS60181257A (en) * | 1984-02-28 | 1985-09-14 | Nippon Stainless Steel Co Ltd | High-strength two-phase stainless steel for vehicle having high young's modulus |
-
1990
- 1990-02-01 JP JP2024131A patent/JPH07107176B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03229841A (en) | 1991-10-11 |
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