JPH0847701A - Manufacture of martensitic stainless steel wire - Google Patents
Manufacture of martensitic stainless steel wireInfo
- Publication number
- JPH0847701A JPH0847701A JP6204211A JP20421194A JPH0847701A JP H0847701 A JPH0847701 A JP H0847701A JP 6204211 A JP6204211 A JP 6204211A JP 20421194 A JP20421194 A JP 20421194A JP H0847701 A JPH0847701 A JP H0847701A
- Authority
- JP
- Japan
- Prior art keywords
- rolled
- stand
- pair
- wire
- rolls
- 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.)
- Granted
Links
Landscapes
- Metal Rolling (AREA)
- Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、マルテンサイト系ステ
ンレス鋼線材の製造方法に関し、更に詳しくは、難加工
性鋼種であるマルテンサイト系ステンレス鋼を熱間圧延
して線径1.５〜5.５ｍｍにまで加工するマルテンサイト
系ステンレス鋼線材の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a martensitic stainless steel wire rod, more specifically, a martensitic stainless steel which is a difficult-to-process steel grade is hot-rolled to have a wire diameter of 1.5-5. The present invention relates to a method for manufacturing a martensitic stainless steel wire rod that is processed to a size of 0.5 mm.
【０００２】[0002]
【従来の技術】線材の製造方法としては、伸線法と圧延
法、またはその両者を組み合わせた方法が知られてい
る。これらのうち、伸線法は、所定孔径のダイスを多段
階に設置し、ここに素材を連続的に通して順次細径化し
ていく方法であって、通常、細線の製造に適用されてい
る。2. Description of the Related Art As a method of manufacturing a wire rod, a wire drawing method and a rolling method, or a method in which both of them are combined is known. Among these, the wire drawing method is a method in which dies having a predetermined hole diameter are installed in multiple stages and the material is continuously passed through the die to successively reduce the diameter, and is usually applied to the production of thin wires. .
【０００３】一方、圧延法は、ロール面を組み合わせる
と所望形状の圧延面（以下、孔型という）になる一対の
ロールから成るスタンドを多段階に設置した圧延機に素
材（以下、被圧延材という）を供給し、これら対ロール
の孔型で順次圧延することにより、所望線径にまで細線
化する方法である。この圧延法は、上記した伸線法に比
べて生産性が高いという利点を備えている。On the other hand, in the rolling method, when a roll surface is combined, a stand composed of a pair of rolls that form a rolling surface having a desired shape (hereinafter referred to as a hole type) is installed in a multi-stage rolling mill (hereinafter, rolled material). Is supplied and is sequentially rolled with a pair of rolls having a hole shape to reduce the wire diameter to a desired wire diameter. This rolling method has the advantage that it has higher productivity than the wire drawing method described above.
【０００４】この圧延法では、被圧延材を導入する側に
孔型がオーバル形状をした対ロールのスタンドを配置
し、その直後に孔型が円形状をした対ロールのスタンド
を配置し、この１組のスタンドで所望の減面率を確保す
るオーバル−丸孔型方式が採用されることがある。この
方式では、円形断面でオーバル孔型の対ロールのスタン
ドに導入された被圧延材はこの対ロールで断面が楕円形
状に圧延されたのち、直ちに次の丸孔型の対ロールのス
タンドに導入されて、ここでより細径の線材に圧延され
る。In this rolling method, a pair of roll pairs having an oval hole shape is arranged on the side where the material to be rolled is introduced, and immediately thereafter, a pair of roll pairs having a circular hole shape is arranged. An oval-round hole type system that secures a desired surface reduction rate with one set of stands may be adopted. In this method, the material to be rolled, which has been introduced into the pair of oval hole type counter rolls with a circular cross section, is rolled into an elliptical section with this pair of rolls, and then immediately introduced to the next round hole type pair roll stand. Then, the wire rod having a smaller diameter is rolled here.
【０００５】ところで、上記したオーバル−丸孔型方式
で被圧延材を圧延する場合、スタンド間において線材の
たおれが発生することがある。ここでいうたおれとは、
オーバル孔型の対ロールから導出された、断面形状が楕
円形をしている偏平な被圧延材が、次の丸孔型の対ロー
ルに導入される際に、前記丸孔型の対ロールの抵抗を受
けて捻転することである。このたおれは、スタンド間の
距離が長い場合や、線材の変形抵抗が低い場合などに多
発する。このようなたおれが発生すると、被圧延材は対
ロールの孔型に正確に入らず、ロール間の隙間等に入り
込み、所定断面形状の線材が得られなくなる。そのた
め、たおれの発生を抑制するためにスタンド間にはロー
ラーガイドが設置されている。ローラーガイドを設置す
ることによりオーバル孔型の対ロールから導出された被
圧延材を丸孔型の対ロールに確実に誘導できるので、寸
法精度の高い線材が得られる。By the way, when the material to be rolled is rolled by the above-mentioned oval-round hole type method, the wire rod sometimes sags between the stands. What I mean here is
Derived from the pair of oval hole type rolls, the flat rolled material having an elliptical cross-sectional shape is introduced into the next pair of round hole type rolls. It is to twist under the resistance. This flapping occurs frequently when the distance between the stands is long or when the deformation resistance of the wire is low. When such sagging occurs, the material to be rolled does not accurately enter the hole shape of the pair of rolls, enters the gap between the rolls, etc., and it becomes impossible to obtain a wire rod having a predetermined cross-sectional shape. Therefore, a roller guide is installed between the stands in order to suppress the occurrence of flapping. By installing the roller guide, the rolled material derived from the pair of oval hole type rolls can be reliably guided to the pair of round hole type rolls, and thus a wire rod having high dimensional accuracy can be obtained.
【０００６】[0006]
【発明が解決しようとする課題】ところで、上記した従
来のオーバル−丸孔型方式の圧延法では、線径が5.５ｍ
ｍ以下の細線を製造することはかなり困難である。その
理由は、前記したローラーガイドを介装することが困難
になるからである。そのため、線径が5.５ｍｍ以下の細
線を得るためには、最初に圧延法で線径5.５ｍｍ程度ま
で被圧延材を細線化し、ついで、それを前記した伸線法
で所望線径にまで更に細線化するという方法が採られ
る。By the way, in the above-described conventional oval-round hole type rolling method, the wire diameter is 5.5 m.
It is quite difficult to manufacture fine wires of m or less. The reason is that it becomes difficult to interpose the roller guide described above. Therefore, in order to obtain a fine wire having a wire diameter of 5.5 mm or less, first the rolling material is thinned to a wire diameter of about 5.5 mm, and then the desired wire diameter is obtained by the wire drawing method described above. The method of further thinning is adopted.
【０００７】しかしながら、この方法は、伸線法も一部
採用するため、圧延法の高生産性が減殺されることにな
る。また、伸線法は、冷間加工であるため、得られる線
材中に歪みが発生するので、伸線後には歪みを除去する
ための焼なまし工程が追加され、必要工程が増加する。
そして、例えば、炭素含有量が多いマルテンサイト系ス
テンレス鋼のような難加工性鋼種の細線を製造する場合
には、圧延時においても、スタンド間の減面率を一度に
高くとることができないため、スタンドを多段に設置せ
ざるを得ず、更に必要工程が増加するという問題があ
る。However, since this method also employs a part of the wire drawing method, the high productivity of the rolling method is diminished. Further, since the wire drawing method is cold working, distortion occurs in the obtained wire rod, so that an annealing step for removing the distortion is added after wire drawing, and the number of necessary steps increases.
And, for example, when manufacturing a fine wire of a difficult-to-work steel type such as a martensitic stainless steel having a high carbon content, even at the time of rolling, the reduction in area between stands cannot be made high at a time. However, there is a problem that the stand must be installed in multiple stages, and the number of required processes is further increased.
【０００８】本発明は、上記した問題を解決し、被圧延
材が難加工性鋼種であるマルテンサイト系ステンレス鋼
であっても、オーバル−丸孔型方式の圧延法だけで、そ
れを高減面率で線径1.５〜5.５ｍｍにまで細線化するこ
とができるマルテンサイト系ステンレス鋼線材の製造方
法の提供を目的とする。The present invention solves the above-mentioned problems, and even if the material to be rolled is martensitic stainless steel, which is a difficult-to-form steel grade, it can be highly reduced by the oval-round hole type rolling method alone. It is an object of the present invention to provide a method for producing a martensitic stainless steel wire rod which can be thinned to have a surface diameter of 1.5 to 5.5 mm.
【０００９】[0009]
【課題を解決するための手段】上記目的を達成するため
に、本発明では、圧延面がオーバル形状を形成する第１
の対ロールと、圧延面が円形状を形成する第２の対ロー
ルとを、前記第１の対ロールが被圧延材の導入側とな
り、前記第２の対ロールが導出側となるように圧延方向
に沿ってそれぞれ複数配置し、前記第１の対ロールにマ
ルテンサイト系ステンレス鋼からなる被圧延材を導入し
て圧延するマルテンサイト系ステンレス鋼線材の製造方
法において、前記第１の対ロールと前記第２の対ロール
との中心間距離をＬ、前記第２の対ロールから導出され
た線材の線径をＤとしたときに、Ｌ／Ｄを２５以下に設
定し、最初の前記第１の対ロールに導入するときの前記
マルテンサイト系ステンレス鋼からなる被圧延材の温度
を８００〜１２００℃に設定し、前記マルテンサイト系
ステンレス鋼からなる被圧延材をそれぞれのロールにつ
いて減面率１０〜３５％で線径1.５〜5.５ｍｍにまで圧
延することを特徴とするマルテンサイト系ステンレス鋼
線材の製造方法が提供される。In order to achieve the above object, the first aspect of the present invention is that the rolling surface forms an oval shape.
And a second pair of rolls whose rolling surface forms a circular shape so that the first pair of rolls is the introduction side of the material to be rolled and the second pair of rolls is the derivation side. In the method for producing a martensitic stainless steel wire rod, which is arranged in plural along each direction, and in which a rolled material made of martensitic stainless steel is introduced into the first opposing roll and rolled, When the distance between the centers of the second pair of rolls is L and the wire diameter of the wire rod derived from the second pair of rolls is D, L / D is set to 25 or less, and the first first The temperature of the rolled material made of the martensitic stainless steel at the time of introducing the rolled material made of the martensitic stainless steel is set to 800 to 1200 ° C., and the rolled material made of the martensitic stainless steel is reduced in area by 10 for each roll. ~ 3 % Method for manufacturing a martensitic stainless steel wire, characterized by rolling up a wire diameter 1.5~5.5mm is provided.
【００１０】本発明方法では、例えば、図１で示したよ
うなスタンドを有する圧延機が採用される。この圧延機
には、被圧延材Ａ1 の導入側に、互いの圧延面を組み合
わせたときに楕円形状のオーバル孔型を形成する一対の
ロール１ａ，１ｂからなる第１スタンド１Ｈ（水平スタ
ンド）が設置され、その後段に、互いの圧延面を組み合
わせたときに円形状の丸孔型を形成する一対のロール２
ａ，２ｂ（図示せず）からなる第２スタンド２Ｖ（垂直
スタンド）が設置される。In the method of the present invention, for example, a rolling mill having a stand as shown in FIG. 1 is adopted. The rolling mill, the introduction side of the rolled material A 1, a pair of rolls 1a to form the oval hole type elliptic shape when combined rolling surface of each other, a first stand 1H consisting 1b (horizontal stand) And a pair of rolls 2 that form a circular round hole when the rolling surfaces are combined with each other.
A second stand 2V (vertical stand) including a and 2b (not shown) is installed.
【００１１】前記第１および第２スタンドからなる対ス
タンドＳ1 に断面が円形状で外径寸法がＤ0 である被圧
延材Ａ1 を第１スタンド１Ｈ側より導入すると、被圧延
材Ａ1 は、前記第１スタンド１Ｈのオーバル孔型で断面
が楕円形状に圧延され、その後、直ちに第２スタンド２
Ｖの丸孔型で断面を円形状に圧延され、最終的には第２
スタンド２Ｖより線径がＤ（被圧延材Ａ1 よりも細径）
の線材Ａ2 となって導出される。[0011] The first and cross pair stand S 1 of a second stand outer diameter a circular shape is introduced from the material to be rolled A 1 first stand 1H-side which is the D 0, the material to be rolled A 1 Is an oval hole type of the first stand 1H, which is rolled into an elliptical cross section, and immediately thereafter, the second stand 2
The V-shaped hole is rolled into a circular cross section, and finally rolled into the second
Wire diameter is D from stand 2V (smaller than rolled material A 1 )
Of the wire rod A 2 .
【００１２】このように、オーバル孔型を有する第１ス
タンドと丸孔型を有する第２スタンドとからなる対スタ
ンドＳ1 により所望の減面率が確保される。ここで、前
記対スタンドＳ1 において、第１スタンド１Ｈと第２ス
タンド２Ｖとの中心間の距離をＬ、線材Ａ2 の線径をＤ
としたとき、これらの関係Ｌ／Ｄの値を２５より大きく
とるとスタンド間において被圧延材のたおれが生じるの
で、Ｌ／Ｄの値は２５以下に設定する。As described above, a desired surface reduction rate is secured by the counter stand S 1 including the first stand having the oval hole type and the second stand having the round hole type. Here, in the pair of stands S 1 , the distance between the centers of the first stand 1H and the second stand 2V is L, and the wire diameter of the wire A 2 is D.
When the value of these relations L / D is larger than 25, the material to be rolled sags between the stands, so the value of L / D is set to 25 or less.
【００１３】尚、第１スタンド１Ｈと第２スタンド２Ｖ
とを近接させることにより、これらスタンド間にローラ
ーガイドは設けなくてもよい。第１スタンド１Ｈと第２
スタンド２Ｖとの中心間距離Ｌの最低値は、ロールの外
径ｄ以下の寸法であるので、対スタンドＳ1 におけるス
タンド中心間距離Ｌは、ロールの外径ｄ以下の寸法まで
近接させることが好ましい。The first stand 1H and the second stand 2V
It is not necessary to provide a roller guide between these stands by bringing the and close to each other. First stand 1H and second
Since the minimum value of the center-to-center distance L with the stand 2V is a dimension equal to or less than the outer diameter d of the roll, the distance L between the center of the stands on the stand S 1 can be made close to the dimension equal to or less than the outer diameter d of the roll. preferable.
【００１４】また、前記対スタンドＳ1 で圧延すること
により得られた線材Ａ2 を更に細径の線材Ａ3 に加工す
る場合、図１に示すように、対スタンドＳ1 の後段に、
対スタンドＳ1 と同様な構成で、各孔型の径が対スタン
ドＳ1 のものよりも小さい対スタンドＳ2 を設置し、被
圧延材Ａ1 を多段階に圧延することが好ましい。尚、前
記対スタンドは所望する線材の寸法や、減面率の組合せ
により対スタンドを圧延方向に複数段設置して構わな
い。更に、対スタンド内における水平，垂直スタンドの
組合せも任意に選択して構わない。[0014] When processing the further small-diameter wire A 3 the wire A 2 obtained by rolling by the pair stand S 1, as shown in FIG. 1, to the subsequent-to-stand S 1,
In a similar configuration as the pair stand S 1, it is preferable that the diameter of each pore type established a small pair stand S 2 than the pair stand S 1, rolling the material to be rolled A 1 in multiple stages. The pair of stands may be installed in a plurality of stages in the rolling direction depending on the desired wire size and the combination of surface reduction rates. Furthermore, the combination of horizontal and vertical stands in the paired stand may be arbitrarily selected.
【００１５】ついで、本発明では、前記被圧延材として
マルテンサイト系ステンレス鋼を用いる。前記被圧延材
は難加工性鋼種であるため、圧延前に加熱処理を施し、
被圧延材の加工性を向上させ、圧延を容易にすることが
行われる。このときの加熱処理は被圧延材が第１スタン
ドに導入される直前に行われる。被圧延材の加熱方法と
しては、例えば、被圧延材への直接通電による通電加熱
が好ましい。Next, in the present invention, martensitic stainless steel is used as the material to be rolled. Since the material to be rolled is a difficult-to-process steel type, it is subjected to heat treatment before rolling,
The workability of the material to be rolled is improved and rolling is facilitated. The heat treatment at this time is performed immediately before the material to be rolled is introduced into the first stand. As a method of heating the material to be rolled, for example, energization heating by directly energizing the material to be rolled is preferable.
【００１６】尚、前記加熱処理は、圧延前に前記被圧延
材を均一に加熱できる方法であれば格別限定されるもの
ではなく、例えば、第１スタンド１Ｈの直前の部分に連
続式加熱炉を設置し、被圧延材が前記加熱炉内を通過し
てから第１スタンド１Ｈに導入される構造にしても構わ
ない。前記加熱方法により加熱した被圧延材の温度が８
００℃より低い場合は、充分な加工性が得られないの
で、圧延加工が困難となり、被圧延材組織中に存在する
炭化物に割れが生じてミクロボイドが発生し、靱延性の
劣化や焼入れ硬さの低下を招く。逆に被圧延材の温度が
１２００℃より高い場合は、被圧延材の組織中に存在す
る炭化物が粗大化して得られる線材の強度低下を招く。
そのため、第１スタンド１Ｈに導入する直前の被圧延材
の温度は８００〜１２００℃に設定する必要がある。The heat treatment is not particularly limited as long as it is a method capable of uniformly heating the material to be rolled before rolling. For example, a continuous heating furnace is provided immediately before the first stand 1H. A structure may be adopted in which the material to be rolled is installed and passed through the heating furnace before being introduced into the first stand 1H. The temperature of the rolled material heated by the heating method is 8
If the temperature is lower than 00 ° C, sufficient workability cannot be obtained, so that the rolling process becomes difficult, and the carbides present in the structure of the material to be cracked generate microvoids, resulting in deterioration of toughness and ductility and quenching hardness. Cause a decrease in On the other hand, when the temperature of the material to be rolled is higher than 1200 ° C., the carbides present in the structure of the material to be rolled become coarse and the strength of the wire rod obtained decreases.
Therefore, the temperature of the material to be rolled immediately before being introduced into the first stand 1H needs to be set to 800 to 1200 ° C.
【００１７】次いで、前記対スタンドへ被圧延材を導入
し、圧延加工を施す際、一つの対スタンドでの減面率が
１０％より低い場合は、加工効率が低くなり、生産性が
向上しない。逆に減面率が３５％より高い場合は、断線
が発生したり、表面にきずが生じるようになり、良好な
線材が得られなくなる。そのため、減面率は、１０〜３
５％に設定する必要がある。Next, when the material to be rolled is introduced into the pair of stands and subjected to rolling, if the area reduction rate of one pair of stands is lower than 10%, the working efficiency becomes low and the productivity is not improved. . On the other hand, if the area reduction rate is higher than 35%, wire breakage will occur, or the surface will be flawed, and a good wire cannot be obtained. Therefore, the reduction rate is 10 to 3
It needs to be set to 5%.
【００１８】本発明で製造する線材は、線径が5.５ｍｍ
よりも小さいものとする。しかしながら、熱間圧延で外
形寸法が1.５ｍｍ以下の線材を製造すると座屈や折損を
起こしやすくなり良好な線材を得ることが難しくなるの
で、本発明方法により製造する線材の外径寸法は1.５〜
5.５ｍｍとする。The wire rod manufactured by the present invention has a wire diameter of 5.5 mm.
Less than. However, when a wire rod having an outer dimension of 1.5 mm or less is produced by hot rolling, buckling or breakage easily occurs, and it becomes difficult to obtain a good wire rod. Therefore, the outer diameter dimension of the wire rod produced by the method of the present invention is 1 .5
It is 5.5 mm.
【００１９】[0019]
【作用】本発明によるマルテンサイト系ステンレス鋼線
材の製造方法は、スタンド中心間距離Ｌと圧延後の線材
の外形寸法Ｄとの関係Ｌ／Ｄを２５以下とし、対スタン
ドを形成する２つのスタンドを近接させているので、被
圧延材は、たおれが発生する前に次の孔型に導入され
る。つまり、近接したスタンドがローラーガイドの役目
も果たし、たおれの発生を抑制している。In the method for manufacturing a martensitic stainless steel wire rod according to the present invention, the relation L / D between the distance L between the centers of the stands and the outer dimension D of the rolled wire rod is set to 25 or less, and two stands forming a pair of stands are formed. Since the rolls are close to each other, the material to be rolled is introduced into the next hole type before the sagging occurs. In other words, the adjacent stands also serve as a roller guide and suppress the occurrence of flapping.
【００２０】また、圧延加工直前の線材の温度を８００
〜１２００℃の範囲に保持しているため、被圧延材の加
工性が向上し、被圧延材の組織中の炭化物の割れを少な
く抑えることができ、欠陥の少ない良好な線材を製造す
ることができる。更に、孔型にオーバル−丸孔型方式を
採用しているので１０〜３５％の高減面率の加工が可能
となっている。The temperature of the wire rod immediately before rolling is set to 800
Since the temperature is maintained in the range of up to 1200 ° C, the workability of the material to be rolled is improved, the cracking of carbides in the structure of the material to be rolled can be suppressed to be small, and a good wire material with few defects can be manufactured. it can. Furthermore, since the oval-round hole type is adopted as the hole type, it is possible to process with a high surface reduction rate of 10 to 35%.
【００２１】[0021]
実施例１〜４、比較例１〜５ マルテンサイト系ステンレス鋼４４０Ｃ（Ｃ：1.０重量
％，Ｃｒ：１7.０重量％，残部がＦｅと不可避的不純
物，ＪＩＳ規格のＳＵＳ４４０Ｃ相当）を予め熱間圧延
により外径寸法Ｄ0 が5.５ｍｍの被圧延材Ａ1 に加工し
た。Examples 1 to 4, Comparative Examples 1 to 5 Martensitic stainless steel 440C (C: 1.0 wt%, Cr: 17.0 wt%, balance Fe and inevitable impurities, JIS standard SUS440C equivalent) was previously prepared. The material A 1 to be rolled having an outer diameter dimension D 0 of 5.5 mm was processed by hot rolling.
【００２２】次いで、前記被圧延材Ａ1 を直接通電によ
り加熱し、図１に示すような、オーバル孔型を有する第
１スタンド１Ｈ（水平スタンド）と丸孔型を有する第２
スタンド２Ｖ（垂直スタンド）とからなる第１の対スタ
ンドＳ1 と、オーバル孔型を有する第３スタンド３Ｈ
（水平スタンド）と丸孔型を有する第４スタンド４Ｖ
（垂直スタンド）とからなる第２の対スタンドＳ2 とを
設置した圧延機に、第１スタンド側より導入し、対スタ
ンドＳ1 と対スタンドＳ2 とにより２段階で熱間圧延を
行った。前記圧延機のロールの寸法は、外径ｄが４０ｍ
ｍ，厚さｔが１５ｍｍである。各スタンドの中心間距離
は、１Ｈ−２Ｖ間（Ｌ）を４０ｍｍ、２Ｖ−３Ｈ間（Ｌ
1 ）を８０ｍｍ、３Ｈ−４Ｖ間（Ｌ2 ）を４０ｍｍとし
た。尚、各スタンド間には、ローラーガイドは設けてい
ない。Next, the material to be rolled A 1 is heated by direct energization, and as shown in FIG. 1, a first stand 1H (horizontal stand) having an oval hole shape and a second stand having a round hole shape.
A first counter stand S 1 including a stand 2V (vertical stand) and a third stand 3H having an oval hole type.
(Horizontal stand) and 4th stand with round hole type 4V
(Vertical stand) and a second pair of stands S 2 and a rolling mill installed from the side of the first stand, hot rolling was performed in two stages by the pair of stands S 1 and the pair of stands S 2 . . The roll of the rolling mill has an outer diameter d of 40 m.
m and the thickness t are 15 mm. The distance between the centers of the stands is 40 mm between 1H-2V (L) and between 2V-3H (L).
1 ) was 80 mm, and 3H-4V (L 2 ) was 40 mm. No roller guide is provided between the stands.
【００２３】また、被圧延材の走行速度は3.４ｍ／ｓｅ
ｃとした。熱間圧延条件としては、第１スタンド１Ｈに
導入する直前の被圧延材Ａ1 の温度をＴ、第１スタンド
１Ｈへ導入される被圧延材Ａ1 の外径寸法をＤ0 、第２
スタンド２Ｖから導出され第３スタンド３Ｈへ導入され
る線材Ａ2 の外形寸法をＤ、対スタンドＳ1 における減
面率をＲ1 、対スタンドＳ1 におけるスタンド中心間距
離Ｌと第２スタンド２Ｖから導出される線材Ａ2 の外径
寸法Ｄとの関係Ｌ／Ｄを（Ｌ／Ｄ）1 、第４スタンド４
Ｖから導出される線材Ａ3 の外形寸法をＤｆ、対スタン
ドＳ2 における減面率をＲ2 、対スタンドＳ2 における
スタンド中心間距離Ｌ2 と第４スタンド４Ｖから導出さ
れる線材Ａ3 の外形寸法Ｄｆとの関係Ｌ2 ／Ｄｆを（Ｌ
／Ｄ）2 としてそれぞれの値を表１に示した。The rolling speed of the material to be rolled is 3.4 m / se.
c. As hot rolling conditions, the temperature of the material A 1 to be rolled immediately before being introduced into the first stand 1H is T, the outer diameter dimension of the material A 1 to be introduced into the first stand 1H is D 0 , the second
The outer dimensions of the wire A 2 which is derived from the stand 2V is introduced into the third stand 3H D, a reduction of area in the to-stand S 1 R 1, from between the stand center in pairs stand S 1 distance L and the second stand 2V The relationship L / D with the outer diameter dimension D of the drawn wire A 2 is (L / D) 1 , the fourth stand 4
The outer dimensions of the wire A 3 derived from V Df, versus a reduction of area in the stand S 2 R 2, between the stand center in pairs stand S 2 distance L 2 between the wire A 3 derived from the fourth stand 4V The relationship L 2 / Df with the external dimension Df is (L
/ D) 2 and the respective values are shown in Table 1.
【００２４】尚、外径寸法Ｄ0 が5.５ｍｍ以下のものは
本発明方法により一度圧延したものを使用している。例
えば、外径寸法が3.７ｍｍの線材は、外径寸法が5.５ｍ
ｍの線材を本発明方法により外径寸法を3.７ｍｍに圧延
したものを再度使用した。得られた線材Ａ3 に対し、断
面の垂直方向Ｄｖと水平方向Ｄｈの寸法を測定し、偏径
差Ｄｓを求めた。Incidentally, those having an outer diameter D 0 of 5.5 mm or less are used after being once rolled by the method of the present invention. For example, a wire rod with an outer diameter of 3.7 mm has an outer diameter of 5.5 m.
The wire having a diameter of m was rolled to an outer diameter of 3.7 mm by the method of the present invention and used again. The dimension of the cross section of the obtained wire A 3 in the vertical direction Dv and the horizontal direction Dh was measured to determine the diameter difference Ds.
【００２５】偏径差Ｄｓは、同一断面での最大寸法と最
小寸法を測定し、その差とした。更に、得られた線材Ａ
3 の先端および後端において、それぞれ２０ｍｍ間隔で
１２ヶ所の部分の断面の垂直方向と水平方向の寸法を測
定し、先端部の外径寸法の平均値Ｄｔおよび後端部の外
径寸法の平均値Ｄｅを求めた。これらの外径寸法より、
先端部と後端部の外径寸法の平均値がともに所定の線材
外径寸法に対して±0.２０ｍｍ以内のものを寸法安定性
良好とし、先端部もしくは後端部の一方またはその両方
の寸法が前記範囲外のものを寸法安定性不良として寸法
安定性を評価した。The eccentricity difference Ds was determined by measuring the maximum dimension and the minimum dimension in the same cross section. Furthermore, the obtained wire A
At the front and rear ends of 3 , the vertical and horizontal dimensions of the cross-section of 12 parts are measured at intervals of 20 mm, and the average of the outer diameter of the front end Dt and the average of the outer diameter of the rear end are measured. The value De was determined. From these outer diameter dimensions,
If the average of the outer diameters of the front and rear ends is within ± 0.20mm with respect to the predetermined outer diameter of the wire material, the dimensional stability is considered to be good, and one or both of the front and rear ends Dimensional stability was evaluated by setting the dimension outside the above range as poor dimensional stability.
【００２６】次いで、圧延中の線材のたおれおよび線材
の割れの有無を目視により観察し、たおれと割れがとも
に無いものを圧延性良好とし、たおれもしくは割れの一
方またはその両方が確認されたものを圧延性不良として
圧延性の評価をした。また、圧延中の線材の座屈および
巻取り時の折損の有無を目視により観察し、座屈と折損
がともに無いものを通線性良好とし、座屈もしくは折損
の一方またはその両方が確認されたものを通線性不良と
して通線性の評価をした。Then, the wire rod during rolling and the presence or absence of cracks in the wire material are visually observed. If there is neither sagging nor cracking, the rolling property is good. The rollability was evaluated as poor rollability. Further, the presence or absence of buckling of the wire rod during rolling and breakage at the time of winding was visually observed, and the wire having no buckling and breakage was considered to have good wireability, and one or both of buckling and breakage was confirmed. The lineability was evaluated as a poor lineability.
【００２７】以上の測定値および評価の結果を表１にあ
わせて示した。The above measured values and evaluation results are also shown in Table 1.
【００２８】[0028]
【表１】 [Table 1]
【００２９】表１の結果から明らかなように、本発明に
よる実施例では、偏径差Ｄｓは0.２０ｍｍ以下と良好で
あり、寸法も安定していた。また、圧延中のたおれは無
く、外観的にも割れやきずは認められなかったので圧延
性は良好であった。更に、圧延中の線材の座屈および巻
取り時の折損は認められなかったので通線性も良好であ
った。このように、本発明による実施例では、難加工性
鋼種であるマルテンサイト系ステンレス鋼を外径寸法5.
５ｍｍ以下の線材に、精度良く圧延加工することができ
た。As is clear from the results shown in Table 1, in the examples according to the present invention, the deviation diameter difference Ds was as good as 0.20 mm or less, and the dimensions were stable. Further, there was no sagging during rolling, and no cracks or flaws were visually recognized, so that the rolling property was good. Further, since buckling of the wire during rolling and breakage during winding were not observed, the wire passability was also good. As described above, in the examples according to the present invention, the martensitic stainless steel, which is a difficult-to-work steel type, has an outer diameter of 5.
The wire rod having a diameter of 5 mm or less could be rolled with high accuracy.
【００３０】それに対し比較例の線材では、圧延機へ導
入する直前の被圧延材の温度が本発明方法の温度範囲よ
り高い比較例１は、変形抵抗が極端に低下したため、た
おれおよび座屈を発生してしまい、圧延性及び通線性は
不良であった。逆に圧延時の温度が本発明方法の温度範
囲より低い比較例２では、加工性が低く、割れおよび巻
取り時の折損が発生してしまい、圧延性及び通線性は不
良であった。また、減面率を４０％以上で加工した比較
例３では、割れが発生してしまい良好な線材は得られな
かった。更に、Ｌ／Ｄを２５以上とした比較例４では、
たおれが発生してしまい正確に圧延することができず、
良好な線材が得られなかった。On the other hand, in the wire of Comparative Example, in Comparative Example 1 in which the temperature of the material to be rolled immediately before being introduced into the rolling mill is higher than the temperature range of the method of the present invention, the deformation resistance was extremely lowered, so that the bending and buckling were prevented. It was generated, and the rolling property and wire passability were poor. On the contrary, in Comparative Example 2 in which the temperature during rolling was lower than the temperature range of the method of the present invention, workability was low, cracking and breakage during winding occurred, and rollability and wire passability were poor. Further, in Comparative Example 3 processed with a surface reduction rate of 40% or more, cracking occurred and a good wire could not be obtained. Furthermore, in Comparative Example 4 in which L / D is 25 or more,
It will not be able to roll accurately because it will sag,
No good wire was obtained.
【００３１】次いで、実施例２の線材の組織を顕微鏡観
察した。その時の組織写真を代用図面として図２に示
す。この写真より炭化物などの割れによるミクロボイド
の面積を測定し、写真の所定範囲の面積とミクロボイド
の面積との比からミクロボイドの面積率を測定した。そ
の結果、実施例２におけるミクロボイドの面積率は1.３
％であった。Then, the structure of the wire of Example 2 was observed under a microscope. A photograph of the structure at that time is shown in FIG. 2 as a substitute drawing. From this photograph, the area of microvoids due to cracks such as carbides was measured, and the area ratio of the microvoids was measured from the ratio of the area of the predetermined range of the photograph to the area of the microvoids. As a result, the area ratio of microvoids in Example 2 was 1.3.
%Met.
【００３２】また、比較例５として、外径寸法が5.５ｍ
ｍの前記４４０Ｃからなる素材に対して室温域で伸線を
施し外径寸法3.０ｍｍの線材に加工した。得られた線材
の組織に対して顕微鏡観察を行った。その時の組織写真
を代用図面として図３に示す。実施例２と同様に、この
写真よりミクロボイドの面積率を測定した。その結果、
比較例５におけるミクロボイドの面積率は５％であっ
た。As Comparative Example 5, the outer diameter dimension is 5.5 m.
m of the 440C material was drawn at room temperature to form a wire having an outer diameter of 3.0 mm. The structure of the obtained wire rod was microscopically observed. A photograph of the structure at that time is shown in FIG. 3 as a substitute drawing. In the same manner as in Example 2, the area ratio of microvoids was measured from this photograph. as a result,
The area ratio of microvoids in Comparative Example 5 was 5%.
【００３３】これらの結果より、室温域で伸線を施した
比較例５に対して、高温で圧延加工を施した実施例２
は、加工にともなって発生する組織内のミクロボイドを
低位に抑えることができた。From these results, in comparison with Comparative Example 5 which was drawn at room temperature, Example 2 which was rolled at high temperature was used.
Was able to suppress the microvoids in the structure generated during processing to a low level.
【００３４】[0034]
【発明の効果】以上の説明で明らかなように、本発明の
マルテンサイト系ステンレス鋼線材の製造方法は、難加
工性鋼種であるマルテンサイト系ステンレス鋼を、外径
寸法が5.５ｍｍ以下の線材に加工する際にも１０〜３５
％といった高減面率で、かつ正確に熱間圧延を行うこと
ができる。As is apparent from the above description, the method for producing a martensitic stainless steel wire rod according to the present invention uses a martensitic stainless steel which is a difficult-to-process steel type and has an outer diameter of 5.5 mm or less. 10-35 when processing into wire
It is possible to perform hot rolling accurately with a high area reduction rate such as%.
【００３５】また、従来、線径の細い線材の製造では圧
延法と伸線法とを組み合わせて行っていたが、本発明方
法により伸線−焼なましの工程を省略することができる
ので、製造コスト低減が実現される。更に、本発明方法
は、線材の組織中のミクロボイドの発生を低位に抑えら
れるので、靱延性劣化の抑制、焼入れ硬さの向上が図
れ、良好な線材が得られる。Conventionally, in the production of a wire material having a small wire diameter, the rolling method and the wire drawing method are combined, but since the wire drawing-annealing step can be omitted by the method of the present invention, Manufacturing cost reduction is realized. Further, according to the method of the present invention, since the generation of microvoids in the structure of the wire can be suppressed to a low level, deterioration of toughness and ductility can be suppressed, quenching hardness can be improved, and a good wire can be obtained.
【００３６】本発明のマルテンサイト系ステンレス鋼線
材の製造方法は、上記のような効果を奏するものであ
り、その工業的価値は大である。The method for producing a martensitic stainless steel wire rod according to the present invention has the above-mentioned effects, and its industrial value is great.
【図１】本発明に用いた圧延機の概略構成図である。FIG. 1 is a schematic configuration diagram of a rolling mill used in the present invention.
【図２】実施例２の組織写真である。（×４００）2 is a photograph of the structure of Example 2. FIG. (× 400)
【図３】比較例５の組織写真である。（×４００）FIG. 3 is a structural photograph of Comparative Example 5. (× 400)
１ａ，１ｂ ロール ２ａ，（２ｂ） ロール Ａ1 被圧延材 Ａ2 第１の対スタンドＳ1 により圧延
された線材 Ａ3 第２の対スタンドＳ2 により圧延
された線材 ｄ ロールの外径 Ｄ0 被圧延材の外径寸法 Ｄ 第２スタンドから導出された線材
の外径寸法 Ｄｆ 第４スタンドから導出された線材
の外径寸法 Ｌ スタンド中心間距離（１Ｈ−２Ｖ
間） Ｌ1 スタンド中心間距離（２Ｖ−３Ｈ
間） Ｌ2 スタンド中心間距離（３Ｈ−４Ｖ
間） １Ｈ 第１スタンド ２Ｖ 第２スタンド ３Ｈ 第３スタンド ４Ｖ 第４スタンド Ｓ1 第１の対スタンド（１Ｈ−２Ｖ） Ｓ2 第２の対スタンド（３Ｈ−４Ｖ） ｔ ロールの厚さ1a, 1b roll 2a, (2b) roll A 1 material to be rolled A 2 wire rod rolled by a first pair of stands S 1 A 3 wire rod rolled by a second pair of stands S 2 d outer diameter of roll D 0 Outer diameter of rolled material D Outer diameter of wire drawn from second stand Df Outer diameter of wire drawn from fourth stand L Distance between stand centers (1H-2V
Between) L 1 stand center-to-center distance (2V-3H
During) L 2 stand center distance (3H-4V
1H 1st stand 2V 2nd stand 3H 3rd stand 4V 4th stand S 1 1st pair of stands (1H-2V) S 2 2nd pair of stands (3H-4V) t Roll thickness
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｃ２１Ｄ 8/06 Ｂ 8821−4Ｋ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Office reference number FI technical display location C21D 8/06 B 8821-4K
Claims (1)
対ロールと、圧延面が円形状を形成する第２の対ロール
とを、前記第１の対ロールが被圧延材の導入側となり、
前記第２の対ロールが導出側となるように圧延方向に沿
ってそれぞれ複数配置し、前記第１の対ロールにマルテ
ンサイト系ステンレス鋼からなる被圧延材を導入して圧
延するマルテンサイト系ステンレス鋼線材の製造方法に
おいて、前記第１の対ロールと前記第２の対ロールとの
中心間距離をＬ、前記第２の対ロールから導出された線
材の線径をＤとしたときに、Ｌ／Ｄを２５以下に設定
し、最初の前記第１の対ロールに導入するときの前記マ
ルテンサイト系ステンレス鋼からなる被圧延材の温度を
８００〜１２００℃に設定し、前記マルテンサイト系ス
テンレス鋼からなる被圧延材をそれぞれのロールについ
て減面率１０〜３５％で線径1.５〜5.５ｍｍにまで圧延
することを特徴とするマルテンサイト系ステンレス鋼線
材の製造方法。1. A first pair of rolls having a rolling surface forming an oval shape, and a second pair of rolls having a rolling surface forming a circular shape, the first pair of rolls being the introduction side of the material to be rolled. ,
A plurality of the second pair of rolls are arranged along the rolling direction so that the second pair of rolls are on the lead-out side, and the material to be rolled made of martensite stainless steel is introduced into the first pair of rolls and rolled. In the method for manufacturing a steel wire rod, when the center-to-center distance between the first pair of rolls and the second pair of rolls is L and the wire diameter of the wire rod derived from the second pair of rolls is D, L / D is set to 25 or less, the temperature of the material to be rolled consisting of the martensitic stainless steel is set to 800 to 1200 ° C. when introduced into the first pair of rolls, and the martensitic stainless steel is set. A method for producing a martensitic stainless steel wire rod, which comprises rolling the material to be rolled up to a wire diameter of 1.5 to 5.5 mm with a surface reduction rate of 10 to 35% for each roll.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20421194A JP3364814B2 (en) | 1994-08-05 | 1994-08-05 | Method for producing martensitic stainless steel wire rod |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20421194A JP3364814B2 (en) | 1994-08-05 | 1994-08-05 | Method for producing martensitic stainless steel wire rod |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0847701A true JPH0847701A (en) | 1996-02-20 |
| JP3364814B2 JP3364814B2 (en) | 2003-01-08 |
Family
ID=16486681
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20421194A Expired - Lifetime JP3364814B2 (en) | 1994-08-05 | 1994-08-05 | Method for producing martensitic stainless steel wire rod |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3364814B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0899101A (en) * | 1994-08-05 | 1996-04-16 | Daido Steel Co Ltd | Manufacture of wire |
| KR20010061653A (en) * | 1999-12-28 | 2001-07-07 | 이구택 | High carbon steel wire rolling mill with groove |
| JP2007136546A (en) * | 2005-10-21 | 2007-06-07 | National Institute For Materials Science | Warm controlled rolling apparatus and warm/cold continuous controlled rolling apparatus |
| CN103624083A (en) * | 2012-08-29 | 2014-03-12 | 上海宝钢工业技术服务有限公司 | Design method of roller used for improving shape quality of steel board |
| CN107138524A (en) * | 2017-07-10 | 2017-09-08 | 中冶赛迪工程技术股份有限公司 | A kind of minimum specification cord steel wire craft arrangement and preparation method |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61150703A (en) * | 1984-12-24 | 1986-07-09 | Keiichiro Yoshida | Method and device for working metallic stock by roll die |
| JPH01210102A (en) * | 1988-02-16 | 1989-08-23 | Daido Steel Co Ltd | Method for rolling of steel bar stock without holding guide |
| JPH0299204A (en) * | 1988-09-30 | 1990-04-11 | Daido Steel Co Ltd | Method for continuous rolling |
| JPH05195082A (en) * | 1991-06-14 | 1993-08-03 | Centre Rech Metall | Preparation of hard steel wire |
| JPH06272763A (en) * | 1993-03-17 | 1994-09-27 | Hitachi Metals Ltd | Manufacture of flat wire and side rail for oil ring |
| JPH0716610A (en) * | 1993-07-05 | 1995-01-20 | Daido Steel Co Ltd | Method for working high-carbon martensitic stainless steel |
| JPH0760301A (en) * | 1993-08-23 | 1995-03-07 | Daido Steel Co Ltd | Method for guideless rolling |
-
1994
- 1994-08-05 JP JP20421194A patent/JP3364814B2/en not_active Expired - Lifetime
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61150703A (en) * | 1984-12-24 | 1986-07-09 | Keiichiro Yoshida | Method and device for working metallic stock by roll die |
| JPH01210102A (en) * | 1988-02-16 | 1989-08-23 | Daido Steel Co Ltd | Method for rolling of steel bar stock without holding guide |
| JPH0299204A (en) * | 1988-09-30 | 1990-04-11 | Daido Steel Co Ltd | Method for continuous rolling |
| JPH05195082A (en) * | 1991-06-14 | 1993-08-03 | Centre Rech Metall | Preparation of hard steel wire |
| JPH06272763A (en) * | 1993-03-17 | 1994-09-27 | Hitachi Metals Ltd | Manufacture of flat wire and side rail for oil ring |
| JPH0716610A (en) * | 1993-07-05 | 1995-01-20 | Daido Steel Co Ltd | Method for working high-carbon martensitic stainless steel |
| JPH0760301A (en) * | 1993-08-23 | 1995-03-07 | Daido Steel Co Ltd | Method for guideless rolling |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0899101A (en) * | 1994-08-05 | 1996-04-16 | Daido Steel Co Ltd | Manufacture of wire |
| KR20010061653A (en) * | 1999-12-28 | 2001-07-07 | 이구택 | High carbon steel wire rolling mill with groove |
| JP2007136546A (en) * | 2005-10-21 | 2007-06-07 | National Institute For Materials Science | Warm controlled rolling apparatus and warm/cold continuous controlled rolling apparatus |
| CN103624083A (en) * | 2012-08-29 | 2014-03-12 | 上海宝钢工业技术服务有限公司 | Design method of roller used for improving shape quality of steel board |
| CN107138524A (en) * | 2017-07-10 | 2017-09-08 | 中冶赛迪工程技术股份有限公司 | A kind of minimum specification cord steel wire craft arrangement and preparation method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3364814B2 (en) | 2003-01-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109332379B (en) | Hot-rolled narrow strip steel for stamping parts and preparation method and application thereof | |
| JPH0847701A (en) | Manufacture of martensitic stainless steel wire | |
| US20070289350A1 (en) | Flat wire manufacturing method of manufacturing flat wire for ring gear | |
| KR100617523B1 (en) | Manufacturing Method of Release Section Material | |
| CN109702014B (en) | Trailer axle squaring device, trailer axle and preparation method thereof | |
| KR100838624B1 (en) | Hot rolling method | |
| CN115430706A (en) | Production method of high-carbon steel wire rod and high-carbon steel wire rod | |
| JP3487469B2 (en) | Wire rod manufacturing method | |
| CN111112330B (en) | Processing method for improving strength of copper strip without causing anisotropy | |
| JP2738280B2 (en) | Manufacturing method of external constant parallel flange channel steel | |
| CN113543901A (en) | Method for manufacturing seamless square steel pipe | |
| JP4213370B2 (en) | Method for producing annealed wire rod for cold working | |
| CN110885922A (en) | Method for manufacturing high-grade corrosion-resistant alloy cold-rolled thin material | |
| JPH09285801A (en) | Method and equipment for manufacturing stainless steel shapes | |
| JPH06292906A (en) | Manufacture of bar and wire rod of titanium and titanium alloy | |
| EP3960316A1 (en) | Rolling-straightening machine and method for manufacturing pipe or bar using rolling-straightening machine | |
| JPH10166097A (en) | Production of different cross-section bar | |
| JPH11172336A (en) | Production of seamless steel tube | |
| JP3308848B2 (en) | Seamless rectangular steel pipe and method of manufacturing the same | |
| JP2970504B2 (en) | Rolling method of constant parallel flange channel steel with external method | |
| JPH11104711A (en) | Production method for seamless square shaped steel pipe | |
| JPH10258303A (en) | Manufacture of square seamless steel tube | |
| RU2062152C1 (en) | Strip metal straightening method | |
| JPH0999303A (en) | Manufacture of cold rolled stainless steel strip for leaf spring excellent in flatness | |
| CN115007647A (en) | Method for stably producing low-carbon shallow-punching steel based on continuous casting and rolling production line |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20071101 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081101 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20081101 Year of fee payment: 6 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091101 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20091101 Year of fee payment: 7 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101101 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20101101 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20111101 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20121101 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20131101 Year of fee payment: 11 |
|
| EXPY | Cancellation because of completion of term |