JPS59136423A - Preparation of rod steel and wire material having spheroidal structure - Google Patents
Preparation of rod steel and wire material having spheroidal structureInfo
- Publication number
- JPS59136423A JPS59136423A JP858683A JP858683A JPS59136423A JP S59136423 A JPS59136423 A JP S59136423A JP 858683 A JP858683 A JP 858683A JP 858683 A JP858683 A JP 858683A JP S59136423 A JPS59136423 A JP S59136423A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- temp
- rolling
- deformation
- cooling
- 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.)
- Pending
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
【発明の詳細な説明】
本発明は棒鋼および線材の製造方法に関し、特に熱間圧
延中の加工熱を利用して圧延ままで炭化物の球状化組織
を得ることができる、棒鋼および線材の製造方法に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing steel bars and wire rods, and in particular, a method for producing steel bars and wire rods that can obtain a spheroidized carbide structure as rolled by utilizing processing heat during hot rolling. It is related to.
冷間鍛造用鋼材は変形能を付与し、変形抵抗を下げるた
めに、また軸受は鋼は耐摩耗性を向上させるために、鋼
中の炭化物を球状化させるのが一般的である。In order to impart deformability to steel materials for cold forging and reduce deformation resistance, and to improve wear resistance in steel for bearings, it is common to spheroidize the carbides in the steel.
これら鋼中の炭化物の球状化を行うために従来は熱間圧
延終了後放冷し、直棒または線材コイルにした後、これ
らを熱処理炉にて再加熱し、球状化焼鈍を施していた。In order to spheroidize the carbides in these steels, conventionally, after hot rolling, the steel was allowed to cool, formed into straight rods or wire rod coils, and then reheated in a heat treatment furnace and subjected to spheroidizing annealing.
すなわち、圧延ままの状態では、焼入性の低い炭素鋼や
圧延後の冷却速度の遅い大径材ではパーライト組織ない
しはフェライト・パーライト組織、また焼入性の高い合
金鋼や圧延後の冷却速度の速いｍ経材ではベイナイト組
織であるものを長時間かけて球状化焼鈍を施していた。In other words, in the as-rolled state, carbon steel with low hardenability and large diameter materials with a slow cooling rate after rolling have a pearlite structure or ferrite-pearlite structure, and alloy steel with high hardenability and a large diameter material with a slow cooling rate after rolling have a pearlite structure. In the case of fast m-warp materials, the bainitic structure was subjected to spheroidizing annealing over a long period of time.
この場合焼鈍時間は、球状化しやすい炭素鋼（例えば３
４５Ｃ）でも１０〜２０時間１、球状化しに“くい合金
鋼（例えばＳＣＭ ４３５ ）や軸受鋼では２０時間以
上も有しており、製造上のネックになっているとともに
、省エネルギの見地からも問題であった。In this case, the annealing time should be set for carbon steel that easily becomes spheroidized (for example, 3
45C), it takes 10 to 20 hours1, while alloy steels that are difficult to spheroidize (e.g. SCM 435) and bearing steels have a lifespan of more than 20 hours, which is a bottleneck in manufacturing as well as from an energy saving perspective. That was a problem.
さらには又長時間の熱処理のため鋼表面の酸化、脱炭の
問題も生じていた。このための球状化焼鈍時間の短縮化
が望まれていた。Furthermore, problems of oxidation and decarburization of the steel surface occurred due to the long heat treatment. Therefore, it has been desired to shorten the spheroidizing annealing time.
そこで、球状化焼鈍を行う前に、鋼に冷間加工（例えば
冷間伸線）を施し、鋼中炭化物に変形破壊を起こさせて
、その後の球状化焼鈍での炭化物の分断凝集を促進せし
めることによって球状化焼鈍処理時間の短縮化を図ると
いう方法が提案された。しかし、この方法では球状化焼
鈍時間は短縮されるものの、冷間加工工程が追加される
ために、全工程を通じての処理時間の短縮という意味で
はいま一つ効果が薄かった。Therefore, before performing spheroidizing annealing, the steel is subjected to cold working (for example, cold wire drawing) to cause deformation failure of the carbides in the steel, thereby promoting fragmentation and agglomeration of the carbides in the subsequent spheroidizing annealing. A method was proposed in which the spheroidizing annealing treatment time was shortened by this. However, although this method shortened the spheroidizing annealing time, it added a cold working step, so it was not very effective in shortening the processing time throughout the entire process.
なお、球状化焼鈍の方法としては良く知られているとお
りＡ、意思上に加熱した後徐冷する方法（徐冷法）、４
７点直下で保持する方法（恒温保持法）、Ａ、点上下に
加熱冷却を繰り返す方法（繰り返し法）がある。In addition, as well-known methods for spheroidizing annealing are A, a method of intentionally heating and then slow cooling (slow cooling method), and 4.
There is a method of holding the temperature directly below point 7 (constant temperature holding method), and a method of repeating heating and cooling above and below point A (repetitive method).
本発明の目的は、炭化物の球状化焼鈍の処理時間を大幅
に短縮できる棒鋼および線材の製造方法を提供すること
にある。An object of the present invention is to provide a method for manufacturing steel bars and wire rods that can significantly shorten the processing time for spheroidizing carbide annealing.
上述した目的を達成するために本発明に依る製造方法は
、熱間加工中に発生する加工熱により鋼温度をＡ、点を
境に上下させることによって圧延ままで球状化組織を得
ることに特徴を有するものである。In order to achieve the above-mentioned object, the manufacturing method according to the present invention is characterized in that a spheroidized structure is obtained in the as-rolled state by raising and lowering the steel temperature from point A using processing heat generated during hot working. It has the following.
本発明に従うと２％以下のＣを含有する鋼を胱Ｉ点以上
に加熱した後変形を加える熱間加工において、圧延途中
でＡｒ７点以下Ａｒ７ ２００”Ｃ以上の温度域まで冷
却し、その後引き続いて圧延で１５％以上の塑性変形を
加え、それによって発生する変形熱によりＡＣｌ点以上
ＡｃＢ点以下の温度域に到達せしめる制御圧延バクーン
を少なくとも２回以上繰り返し球状化組織を得ることを
特徴とする棒鋼および線材の製造方法が提供される。According to the present invention, in hot working where steel containing 2% or less of C is heated above the bladder I point and then deformed, it is cooled to a temperature range of below the Ar7 point and above 200"C during rolling, and then A controlled rolling process is repeated at least twice to obtain a spheroidized structure, in which a plastic deformation of 15% or more is applied by rolling, and the resulting deformation heat is used to reach a temperature range from the ACl point to the AcB point. A method of manufacturing steel bars and wire rods is provided.
以下本発明の要件について詳細に説明する。The requirements of the present invention will be explained in detail below.
まずＣ量に関しては、Ｃｉが２％を越えると状態図にお
けるオーステナイト相の領域が非常に狭くなると共に、
初析セメタイトのオーステナイト粒界上析出量が多くな
るため熱間加工性を劣化させ熱間圧延中の割れが生じゃ
すくなるのでＣｉを２％以下とした。First, regarding the amount of C, when the amount of Ci exceeds 2%, the austenite phase region in the phase diagram becomes very narrow, and
Since the amount of pro-eutectoid cementite precipitated on austenite grain boundaries increases, hot workability deteriorates and cracks are more likely to occur during hot rolling, the Ci content is set to 2% or less.
更に、本発明の方法を適用する鋼は所望の強度、延性を
与えるため、Ｓｉ、Ｍｎの他、Ｃｒ、Ｍｏ等の合金化元
素を含むことができる。更に脱酸剤として５ｏｌＡｌを
含むほか、Ｐ、Ｓ等の不純物は成品に所望の特性及び製
造方法より所定の範囲に限定されるが、これらは本発明
の特徴ではないのでこれ以上詳述しない。Furthermore, the steel to which the method of the present invention is applied can contain alloying elements such as Cr, Mo, etc. in addition to Si and Mn in order to provide desired strength and ductility. Furthermore, in addition to containing 5olAl as a deoxidizing agent, impurities such as P and S are limited to a predetermined range depending on the desired characteristics of the product and the manufacturing method, but since these are not characteristics of the present invention, they will not be described in further detail.
大型のブルームあるいはビレットを粗圧延するには、へ
Ｃ／点より低い温度では変形抵抗が急激に大きくなり実
質的に圧延不能であるため、圧延前の加熱温度ばＡｃ７
点以上が望ましい。In order to roughly roll a large bloom or billet, the heating temperature before rolling should be AC7, since the deformation resistance increases rapidly at a temperature lower than the HeC/point, making rolling virtually impossible.
Points or higher are desirable.
炭化物の球状化に対しては、予め加工を与えて、炭化物
の変形破壊を行った後球状化焼鈍を施すと極めて有効で
あることは周知の事実であり、本発明もこの炭化物の変
形破壊を利用したものである。It is a well-known fact that it is extremely effective to process the carbide in advance to cause deformation and fracture, and then perform spheroidization annealing to prevent the deformation and fracture of the carbide. It was used.
すなわち、従来では、圧延放冷後冷間加工を施して、炭
化物の変形破壊を行う方法が採られていたが、本発明で
はこれを熱間圧延中に行おうとするものである。従って
圧延途中で既に炭化物が析出していなくてはならず、こ
のためには計２点以下まで冷却する必要がある。That is, conventionally, a method has been adopted in which deformation fracture of carbides is performed by cold working after rolling and cooling, but the present invention attempts to perform this during hot rolling. Therefore, carbides must have already precipitated during rolling, and for this purpose it is necessary to cool the steel to a total of two points or less.
しかし、Ａｒ７２００°Ｃより低くなると変形抵抗が非
常に大きくなり、実質的にその後の圧延が困難となるた
め、計１点以下、Ａｒｔ ２００ ’Ｃ以上の温度域ま
で冷却することとした。冷却方法としてはと強制冷却（
水冷、風冷）が好ましいが、可能ならば自然放冷でもよ
い。However, if the temperature is lower than Ar 7200°C, the deformation resistance becomes very large and subsequent rolling becomes substantially difficult. Therefore, it was decided to cool down to a temperature range of 1 point or less in total and above Art 200'C. The cooling method is forced cooling (
Water cooling, wind cooling) are preferred, but natural cooling may also be used if possible.
前述のとおり圧延によって炭化物に変形破壊を生ぜしめ
る必要があり、また後述するように、圧延での変形熱に
よって温度上昇を図り少なくともへＣ／点の温度まで到
達せしむる必要があるが、このためには少なくとも１５
％の塑性変形を与える必要があるので、圧延により１５
％以上の塑性変形を加えることとした。但し、この場合
の圧延ば１バスとは限らず連続的に２バス以上で１５％
の変形を与えても良い。As mentioned above, it is necessary to cause deformation fracture in the carbide by rolling, and as will be described later, it is necessary to raise the temperature by the heat of deformation during rolling to reach at least a temperature of -C/point. for at least 15
It is necessary to give plastic deformation of 15% by rolling.
% or more of plastic deformation was applied. However, in this case, rolling is not limited to one bath, but 15% for two or more continuous baths.
It is also possible to give a deformation of .
既に述べたように従来からＡ１点の上下に加熱冷却を繰
り返す球状化焼鈍方法（繰り返し法）が行われているＴ
この原理は４７点以下で析出した炭化物をＡ、意思上に
加熱し炭化物の一部固溶（分断）を図り、続いてＡ１点
以下に冷却しながら分断された炭化物の凝集を図り、そ
れを繰り返すことにより、完全な球状化組織を得ようと
するものである。As already mentioned, the spheroidizing annealing method (repetitive method) in which heating and cooling are repeated above and below the A1 point has traditionally been used.
This principle is to intentionally heat the carbide precipitated at 47 points or below to partially dissolve (divide) the carbide, then cool it to below the A1 point to coagulate the separated carbide. By repeating this process, the aim is to obtain a completely spheroidized tissue.
本発明に依る製造方法では前項で述べたように、自然冷
却あるいは強制冷却と、１５％以上の圧延によって生じ
る変形熱による昇温でへ１点を上下させるようにした。In the manufacturing method according to the present invention, as described in the previous section, the temperature is increased by natural cooling or forced cooling and the heat of deformation generated by rolling by 15% or more to raise or lower the point.
従って変形熱による昇温後の温度はＡｃ１点以上に到達
する必要がある。しかしＡ’ｃ Ｂ点を越えると炭化物
は完全に固溶してしまうため、Ａｃ７点以上Ａｃ３点以
下の温度域に限定した。更にこの制御圧延パターンは２
回以上繰り返さなければ、その効果があまり表れないた
め少なくとも２回は繰り返すことが好ましい。Therefore, the temperature after heating due to deformation heat needs to reach the Ac1 point or higher. However, if the A'c B point is exceeded, the carbide will completely dissolve into solid solution, so the temperature range is limited to 7 Ac points or more and 3 Ac points or less. Furthermore, this controlled rolling pattern is
It is preferable to repeat the process at least twice, as the effect will not be noticeable unless the process is repeated more than once.
以下本発明による棒鋼および線材の製造方法を実施例に
ついて説明する。The method for producing steel bars and wire rods according to the present invention will be described below with reference to Examples.
実庭拠
通常の溶解法により、第１表に示される成分を有する鋼
を製造し、予め１５．４φｍｍ〜１６４．０φｍｍの棒
鋼とし、これらを４時間均熱した後１１．０φｍｍに圧
延した。圧延は＃１〜＃３圧延、＃４〜＃６圧延、＃７
〜＃９圧延をそれぞれ連続的に圧延し、＃３と＃４、＃
６と＃７の間で強制風冷により制御冷却を施した。第２
表に各画の加熱温度および＃１〜＃３圧延、＃４〜＃６
圧延、＃７〜＃９圧延における圧延開始温度、圧延終了
温度、圧下率ならびに平衡変態温度を記載した。Steel having the components shown in Table 1 was produced by a conventional melting method based on actual practice. Steel bars having a diameter of 15.4 mm to 164.0 mm were prepared in advance, and after soaking for 4 hours, the steel bars were rolled to a diameter of 11.0 mm. Rolling is #1 to #3 rolling, #4 to #6 rolling, and #7 rolling.
~ #9 rolling is continuously rolled, #3, #4, #
Controlled cooling was performed between #6 and #7 by forced air cooling. Second
The table shows the heating temperature of each stroke, #1 to #3 rolling, #4 to #6
The rolling start temperature, rolling end temperature, rolling reduction ratio, and equilibrium transformation temperature in rolling, #7 to #9 rolling were described.
各条件で仕上圧延を行った後、自然放冷および保温カバ
ーを用いて２０℃／分の調整冷却を施し、それらの組織
から得られた球状化率を第２表に併せて示す。 第２表
にいう球状化率は以下の方法により決定した。即ち、組
織を走査型電子顕微鏡で撮影し、白く写った炭化物の長
径と短径を測定し、長径／短径の値を求めた。測定は１
００個以上の炭化物についてランダムに行い、長径／短
径のヒストグラムを求め、その値が３．０以下の炭化物
数の全炭化物数に対する割合を％で示し、球状化率と定
義した。After finish rolling under each condition, natural cooling and controlled cooling at 20° C./min using a heat insulating cover were performed, and the spheroidization rates obtained from these structures are also shown in Table 2. The spheroidization rate shown in Table 2 was determined by the following method. That is, the structure was photographed using a scanning electron microscope, the long axis and short axis of the white carbide were measured, and the value of the long axis/breadth axis was determined. Measurement is 1
This was carried out randomly for 00 or more carbides, a histogram of major axis/minor axis was obtained, and the ratio of the number of carbides whose value was 3.0 or less to the total number of carbides was expressed as %, and was defined as the spheroidization rate.
第１表の各画を通常圧延（１０５０℃加熱−９５０℃圧
延開始−１０４０°Ｃ圧延終了−６０％圧下−自然放冷
）した場合には、Ａ、Ｂ、Ｅ鋼の組織における炭化物は
ほぼすべてラメラ−状になっており、球状化率としては
すべて２％以下である（Ｃ，Ｄ鋼はベイナイト組織のた
め球状化率測定不能）。これに対し、第２表に示した本
発明による圧延材の球状化率はすべて７５％以上となっ
ており、圧延後調整冷却を施すと９５％以上に達する。When each stroke in Table 1 is normally rolled (heating at 1050°C - start of rolling at 950°C - end of rolling at 1040°C - 60% reduction - natural cooling), carbides in the structure of steels A, B and E are almost All of them have a lamellar shape, and the spheroidization rate is 2% or less in all steels (C and D steels have a bainitic structure, so the spheroidization rate cannot be measured). On the other hand, the spheroidization rates of the rolled materials according to the present invention shown in Table 2 are all 75% or more, and reach 95% or more when conditioned cooling is performed after rolling.
従って球状化焼鈍を省略することも十分可能である。Therefore, it is quite possible to omit the spheroidizing annealing.
次に第２表に示した鋼のうちＡ鋼（８００℃加熱）、Ｄ
鋼（９００℃加熱）、Ｃ鋼（７５０℃加熱）、Ｄ鋼（１
０００℃加熱）について、＃１〜＃３圧延後自然放冷、
＃１〜＃６圧延後自然放冷、＃１〜＃９圧延後自然放冷
したもの（以上の圧延条件は第２表に示す通り）および
通常圧延したものの球状化率をそれぞれ第１図に示す。Next, among the steels shown in Table 2, steel A (heated at 800°C), steel D
Steel (heated to 900℃), C steel (heated to 750℃), D steel (1
000℃ heating), #1 to #3 natural cooling after rolling,
Figure 1 shows the spheroidization rates of #1 to #6 rolled and naturally cooled, #1 to #9 rolled and then naturally cooled (the above rolling conditions are shown in Table 2), and normally rolled. show.
これに坐ると＃ｌ〜＃６および＃１〜＃９圧延後自然放
冷したものはすべて６５％以上の球状化率を示すが、＃
１〜＃３圧延後自然放冷したものは２５％以下と非常に
低しへ球状化率をしめず。すなわち、本発明の制御圧延
）ｉターンは２回以上繰り返さなければその効果があま
り発揮されないことがわかる。When sitting on this, #1 to #6 and #1 to #9 that were naturally cooled after rolling all showed a spheroidization rate of 65% or more, but #
1 to #3 that were allowed to cool naturally after rolling had a very low spheroidization rate of 25% or less. That is, it can be seen that the effect of the controlled rolling (i-turn) of the present invention is not exhibited much unless it is repeated two or more times.
以上説明した通り本発明に依る棒鋼および線材の製造方
法においては、熱間圧延中の加工熱を利用して鋼の温度
を的点を境に上下させることによって圧延ままで炭化物
の球状化組織を得ることができ、そのためその後の球状
化焼鈍の処理時間は大幅に短縮でき、用途によっては完
全に球状化焼鈍を省略することも可能である。As explained above, in the method for manufacturing steel bars and wire rods according to the present invention, the temperature of the steel is raised and lowered at a target point using the processing heat during hot rolling, thereby forming a spheroidized structure of carbides during rolling. Therefore, the processing time for subsequent spheroidizing annealing can be significantly shortened, and depending on the application, spheroidizing annealing can be completely omitted.
第１図は、Ａ鋼（８００°Ｃ加熱）、Ｂ鋼（９００°Ｃ
加熱）、Ｃ鋼（７００℃加熱）、Ｄ鋼（１０００℃加熱
）について−＝１．通常圧延、■、＃１〜＃３圧延後自
然放冷、■、＃１〜＃６圧延後自然放冷、■。
＃１〜＃９圧延後自然放冷したものの球状化率をそれぞ
れ示した図である。
出願人 住友金属工業株式会社
代理人 弁理士 新居止音
第１図Figure 1 shows steel A (heated to 800°C) and steel B (heated to 900°C).
-=1 for steel C (heated to 700°C) and steel D (heated to 1000°C). Normal rolling, ■, #1 to #3 natural cooling after rolling, ■, #1 to #6 natural cooling after rolling, ■. It is a figure showing the spheroidization rate of #1 to #9 which were naturally cooled after rolling. Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent Attorney Arai Yazuon Figure 1
Claims (1)
変形を加える熱間加工において、圧延途中でＡｒ２点以
意思、−２００℃以上の温度域まで冷却し、その後引き
続いて圧延で１５％以上の塑性変形を加え、それによっ
て発生する変形熱によりＡｃ／点以上Ａｃ３点以下の温
度域に到達せしめる制御圧延パターンを少なくとも２回
以上繰り返し球状化組織を得ることを特徴とする棒鋼お
よび線材の製造方法。In hot working where steel containing 2% or less of C is heated above the C7 point and then deformed, it is cooled to a temperature range of -200°C or higher above the Ar2 point in the middle of rolling, and then subsequently rolled. A steel bar characterized by obtaining a spheroidized structure by repeating a controlled rolling pattern of applying plastic deformation of 15% or more and causing the resulting deformation heat to reach a temperature range of Ac/point to Ac3 point at least twice. Method of manufacturing wire rods.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP858683A JPS59136423A (en) | 1983-01-21 | 1983-01-21 | Preparation of rod steel and wire material having spheroidal structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP858683A JPS59136423A (en) | 1983-01-21 | 1983-01-21 | Preparation of rod steel and wire material having spheroidal structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59136423A true JPS59136423A (en) | 1984-08-06 |
Family
ID=11697097
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP858683A Pending JPS59136423A (en) | 1983-01-21 | 1983-01-21 | Preparation of rod steel and wire material having spheroidal structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59136423A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57151738A (en) * | 1981-03-13 | 1982-09-18 | Hitachi Techno Eng Co Ltd | Suction nozzle for sandy sludge dredger |
| US4702778A (en) * | 1985-01-28 | 1987-10-27 | Nippon Steel Corporation | Method for softening rolled medium carbon machine structural steels |
| US5104159A (en) * | 1990-01-11 | 1992-04-14 | Kyukichi Sugiyama | Threadless coupling for pipes and an air-tight inner cylinder therefor |
| EP0523375A2 (en) * | 1991-06-14 | 1993-01-20 | Nippon Steel Corporation | Process for producing steel bar wire rod for cold working |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59126720A (en) * | 1983-01-11 | 1984-07-21 | Kawasaki Steel Corp | Direct spheroidizing treatment of steel material |
-
1983
- 1983-01-21 JP JP858683A patent/JPS59136423A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59126720A (en) * | 1983-01-11 | 1984-07-21 | Kawasaki Steel Corp | Direct spheroidizing treatment of steel material |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57151738A (en) * | 1981-03-13 | 1982-09-18 | Hitachi Techno Eng Co Ltd | Suction nozzle for sandy sludge dredger |
| US4702778A (en) * | 1985-01-28 | 1987-10-27 | Nippon Steel Corporation | Method for softening rolled medium carbon machine structural steels |
| US5104159A (en) * | 1990-01-11 | 1992-04-14 | Kyukichi Sugiyama | Threadless coupling for pipes and an air-tight inner cylinder therefor |
| EP0523375A2 (en) * | 1991-06-14 | 1993-01-20 | Nippon Steel Corporation | Process for producing steel bar wire rod for cold working |
| EP0523375A3 (en) * | 1991-06-14 | 1995-05-17 | Nippon Steel Corp | Process for producing steel bar wire rod for cold working |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4018905B2 (en) | Hot rolled wire rod and bar for machine structure and manufacturing method thereof | |
| CN103210106B (en) | High-toughness cold-drawn non-heat-treated wire rod, and method for manufacturing same | |
| JP3113137B2 (en) | Manufacturing method of high toughness rail with pearlite metal structure | |
| JPH06299240A (en) | Manufacture of steel material for bearing having excellent spheroidizing characteristic | |
| JP3554506B2 (en) | Manufacturing method of hot-rolled wire and bar for machine structure | |
| JPS59136421A (en) | Preparation of rod steel and wire material having spheroidal structure | |
| JP4061003B2 (en) | Cold forging bar wire with excellent induction hardenability and cold forgeability | |
| JPS59136423A (en) | Preparation of rod steel and wire material having spheroidal structure | |
| JPH02107743A (en) | Ultrahigh tensile strength pc steel wire or steel rod excellent in uniform elongation and its production | |
| JPS59136422A (en) | Preparation of rod steel and wire material having spheroidal structure | |
| JPH0570685B2 (en) | ||
| JP3864492B2 (en) | Spheroidizing annealing method for steel | |
| JPH0426716A (en) | Short-time spheroidization annealing method for steel bar and wire | |
| JPS61153230A (en) | Production of low-alloy steel wire rod which permits quick spheroidization | |
| KR100435461B1 (en) | A method for manufacturing steel material for cold forging with low property deviation | |
| KR102326245B1 (en) | Steel wire rod for cold forging and methods for manufacturing thereof | |
| JPH10298641A (en) | Production of steel excellent in spheroidize-annealing treatability | |
| KR19980037662A (en) | Manufacturing method of high alloy steel wire for homogeneous spheroidization | |
| JPH0353021A (en) | Manufacture of high carbon steel for spheroidizing | |
| JP2002060841A (en) | Method for producing bar or wire rod | |
| JPS60149723A (en) | Manufacture of steel bar or wire rod having spheroidized structure | |
| KR101500210B1 (en) | High carbon soft wire rod capable of eliminating softening treatment and method for manufaturing the same | |
| JPH024917A (en) | Steel stock for spheroidizing treatment and its production | |
| KR101304670B1 (en) | Steel without spheroidizing heat treatment and method for manufacturing the same | |
| KR19980044919A (en) | Method of manufacturing medium carbon steel wire |