JPS62240721A - Production of rolled steel products having excellent low-temperature toughness - Google Patents
Production of rolled steel products having excellent low-temperature toughnessInfo
- Publication number
- JPS62240721A JPS62240721A JP8418386A JP8418386A JPS62240721A JP S62240721 A JPS62240721 A JP S62240721A JP 8418386 A JP8418386 A JP 8418386A JP 8418386 A JP8418386 A JP 8418386A JP S62240721 A JPS62240721 A JP S62240721A
- Authority
- JP
- Japan
- Prior art keywords
- cooling
- steel products
- temperature
- line
- steel material
- 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
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 83
- 239000010959 steel Substances 0.000 title claims abstract description 83
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 238000001816 cooling Methods 0.000 claims abstract description 44
- 238000005259 measurement Methods 0.000 claims abstract description 7
- 239000000463 material Substances 0.000 claims description 59
- 238000010791 quenching Methods 0.000 claims description 38
- 230000000171 quenching effect Effects 0.000 claims description 38
- 239000002344 surface layer Substances 0.000 claims description 9
- 238000003303 reheating Methods 0.000 claims description 3
- 239000000498 cooling water Substances 0.000 abstract description 19
- 238000002347 injection Methods 0.000 abstract description 12
- 239000007924 injection Substances 0.000 abstract description 12
- 238000005096 rolling process Methods 0.000 abstract description 12
- 238000007664 blowing Methods 0.000 abstract description 4
- 238000005098 hot rolling Methods 0.000 abstract description 2
- 238000001035 drying Methods 0.000 abstract 1
- 230000000717 retained effect Effects 0.000 abstract 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- 230000014509 gene expression Effects 0.000 description 7
- 238000012546 transfer Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000009529 body temperature measurement Methods 0.000 description 3
- 230000003111 delayed effect Effects 0.000 description 3
- 238000012937 correction Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 229910000734 martensite Inorganic materials 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 101100129232 Danio rerio mafaa gene Proteins 0.000 description 1
- 229910001563 bainite Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000001143 conditioned effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 210000003746 feather Anatomy 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 210000002966 serum Anatomy 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
- B21B45/0203—Cooling
- B21B45/0209—Cooling devices, e.g. using gaseous coolants
- B21B45/0215—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes
- B21B45/0224—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes for wire, rods, rounds, bars
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/54—Furnaces for treating strips or wire
- C21D9/56—Continuous furnaces for strip or wire
- C21D9/573—Continuous furnaces for strip or wire with cooling
- C21D9/5732—Continuous furnaces for strip or wire with cooling of wires; of rods
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
この発明は低温靭性の優れた圧延鋼材の製造方法に関す
る。DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing rolled steel materials with excellent low-temperature toughness.
（従来の技術）
低温靭性の優れた圧延鋼材の製造手段として、例えば特
開昭５７−１１４６：１８のように所定の直径寸法まで
熱間圧延した後、引き続いて水噴射冷却により鋼材の表
層部をＡｒ＋変態温度以上からベイナイト変態温度以下
まで急冷し、復熱せしめる方法がある。すなわち、鋼材
表面の熱伝達率を鋼材内部の断面方向熱伝達率より大き
くなるように冷却し、そして、急冷後鋼材に高圧空気を
吹き付けて水切りし１次いでこの冷却された鋼材は水冷
装置と冷却床あるいは巻取機との間を大気中で搬送され
ながら、高温中心部からの熱伝導で表層部を復熱するも
のである。(Prior Art) As a means of manufacturing rolled steel materials with excellent low-temperature toughness, for example, as in JP-A-57-1146:18, after hot rolling to a predetermined diameter dimension, the surface layer of the steel material is subsequently cooled by water jet cooling. There is a method of rapidly cooling from above Ar+ transformation temperature to below bainite transformation temperature and reheating. That is, the steel material is cooled so that the heat transfer coefficient on its surface is greater than the heat transfer coefficient in the cross-sectional direction inside the steel material, and after quenching, high pressure air is blown onto the steel material to drain water. While being conveyed in the atmosphere between the floor or the winder, the surface layer is reheated by heat conduction from the high-temperature center.
水冷装置は、特公昭５６−４８５６６にて提案されてい
るように、タンデムに配置された複数の冷却ユニット（
冷却箱）からなっている、各冷却箱は環状の順噴射ノズ
ルまたは逆噴射ノズルを備えており、ノズルから冷却水
を鋼材に高圧で噴射する。As proposed in Japanese Patent Publication No. 56-48566, a water cooling system consists of multiple cooling units (
Each cooling box is equipped with an annular forward injection nozzle or reverse injection nozzle, which injects cooling water at high pressure into the steel material.
また、冷却箱列の途中に上記水切り装置が配置されてい
るや
この種の装置においては、圧延鋼材に所要の機械的性質
を与えるために、急冷長さを謳整して水切り直後に鋼材
表面温度を測定すると共に、冷却装置の出側から十分離
れた位置で復熱後の鋼材温度を測定し、それぞれの位置
で目標温度になるように冷却水量を調整していた。In addition, in this type of equipment where the above-mentioned draining device is placed in the middle of the cooling box row, in order to give the rolled steel the required mechanical properties, the quenching length is adjusted and the steel surface is immediately removed after draining. In addition to measuring the temperature, the temperature of the steel material after recuperation was also measured at a location sufficiently far from the outlet side of the cooling device, and the amount of cooling water was adjusted to reach the target temperature at each location.
（発明か解決しようとする問題点）
従来の方法は、冷却装置の出側から十分離れた位置て測
定する復熱温度を冷却水量制御情報として使用している
ため、不具合が生じた場合の同−鋼材内および次の圧延
鋼材への改善のためのアクションか遅れる問題かある。(Problem to be solved by the invention) In the conventional method, the recuperation temperature measured at a position sufficiently far from the outlet side of the cooling device is used as cooling water amount control information, so it is difficult to solve the same problem in the event of a problem. - There are problems that delay action for improvement within the steel and to the next rolled steel.
すなわち、急冷後後熱温度の測定点までに到達する時間
は、おおよそ１０〜６０秒あるので、同−鋼材内のアク
ションは２その時間分だけ遅れることになるし、現在の
圧延鋼材から次の圧延鋼材までの間ピッチか前記の到達
時間より短かくなる場合にもアクションが遅れることに
なる。In other words, since it takes approximately 10 to 60 seconds to reach the measuring point of the after-heat temperature after quenching, the action within the same steel material will be delayed by that time, and the next step from the current rolled steel material will be delayed by that amount of time. The action will also be delayed if the pitch to the rolled steel material is shorter than the above-mentioned arrival time.
また、目的の圧延鋼材を連続して製造する場合ても、前
記の問題から圧延調整材を使って概略の急冷長さおよび
水量を確認する必要があった。従ってその時間は真の生
産時間にならないと同時に、圧延調整材はスクラップと
なる問題かあった。このため本出願人においてより適切
な温度管理を行なうための方法として、先に特願昭６０
−２１１２８６５および特願昭６０−２４２８６６を提
案した。しかしながら、圧延にかかる棒線鋼材のサイズ
と圧延速度、すなわち冷却ラインを通過する速度を考慮
する必要かあった。Furthermore, even when the desired rolled steel material is manufactured continuously, due to the above-mentioned problem, it is necessary to confirm the approximate quenching length and water amount using a rolling adjustment material. Therefore, there was a problem that the time did not become true production time, and at the same time, the rolled conditioned material was scrapped. For this reason, the present applicant previously filed a patent application in 1986 as a method for more appropriate temperature control.
-2112865 and Japanese Patent Application No. 60-242866. However, it was necessary to take into consideration the size and rolling speed of the steel rod material during rolling, that is, the speed at which it passes through the cooling line.
（問題点を解決するための手段）
本発明は、必要冷却長さに設定された急冷ラインの最終
端からｌ〜２ｍａｆｌれた測定点で鋼材の表面温度を、
あらかじめ特定した範囲内に入るように冷却条件を２ｇ
Ｊ整し、低温靭性に憬れた鋼材を製造しようとするもの
である。(Means for Solving the Problems) The present invention measures the surface temperature of the steel material at a measuring point 1 to 2 mafl away from the final end of the quenching line set to the required cooling length.
Cooling conditions are set to 2g to fall within a pre-specified range.
The aim is to manufacture steel materials with J-conditioning and poor low-temperature toughness.
すなわち、所定の直径寸法まで圧延し、引き続いて急冷
ラインを通過せしめることにより、表層部を下記の（１
）式で示す範囲内で与えられる温度まで急冷し、次いで
復熱ラインにおいて内部保有熱により表層部を復熱せし
めることを特徴とする低温靭性の優れた圧延鋼材の製造
方法である。That is, by rolling it to a predetermined diameter and then passing it through a quenching line, the surface layer is transformed into the following (1)
This is a method for producing rolled steel materials with excellent low-temperature toughness, which is characterized by rapidly cooling to a temperature given within the range shown by the formula ( ), and then reheating the surface layer using internal heat in a recuperation line.
１４５−ｔ ／ ｒ ２ ＋ １３０ ≦Ｔ
≦ １５２・ｔ ／ ｒ ” ＋ ２４０・・
・（１）
ｔ：急冷終了から測定位ｇ！！＠までの経過時間（ｈｒ
）
ｒ：鋼材の半径（ｍ）
Ｔ：急冷後冷却ラインから１〜２ｍ離れた場所で測定す
る温度（℃）
第１図は、この発明の実施態様の一例を示す説明図であ
る０図面に示すように、仕上圧延４１１に続いて冷却装
置３および巻取機２１か配置されている。■、■、■は
各要所での温度測定点を示す。145-t/r2+130≦T
≦ 152・t/r”+240・・
・(1) t: Measurement position g from the end of rapid cooling! ! Elapsed time until @ (hr
) r: Radius of the steel material (m) T: Temperature measured at a location 1 to 2 m away from the cooling line after quenching (°C) As shown, the cooling device 3 and the winding machine 21 are arranged following the finish rolling 411. ■, ■, ■ indicate temperature measurement points at each important point.
冷却装に３は急冷ライン４と復熱ライン５とに分かれて
いる。急冷ライン４は一列に並ぶ複数の冷却箱７および
冷却水逆噴射装置１２よりなっている。各冷却箱７は環
状の順噴射ノズルまたは逆噴射ノズル（いずれも図解省
略）を備えている。The cooling system 3 is divided into a rapid cooling line 4 and a recuperation line 5. The rapid cooling line 4 includes a plurality of cooling boxes 7 and a cooling water reverse injection device 12 arranged in a row. Each cooling box 7 is equipped with an annular forward injection nozzle or a reverse injection nozzle (both illustrations are omitted).
冷却箱７を貫通して走行する鋼材Ｍはノズルにより周囲
から冷却水か噴射され冷却される。急冷ライン４と復熱
ライン５との間に水切り装置ｌｌか配置されている。水
切り装置１．１は冷却水逆噴射装置１２とこれの出側に
隣接する空気吹付は装置１３とからなっている。急冷ラ
イン４で冷却され水切り装２１１１に入った鋼材Ｍは、
まず冷却水逆噴射装置１２において、鋼材Ｍに付着して
同伴された冷却水が逆噴射で吹き払われる。引き続き空
気吹付は装置１３において残留付着水が高圧空気て吹き
飛ばされ、鋼材の表面は乾燥される。The steel material M passing through the cooling box 7 is cooled by being sprayed with cooling water from the surrounding area by a nozzle. A draining device 11 is arranged between the quenching line 4 and the recuperation line 5. The draining device 1.1 consists of a cooling water reverse injection device 12 and an air blowing device 13 adjacent to this on the outlet side. The steel material M that has been cooled in the quenching line 4 and entered the draining device 2111 is
First, in the cooling water reverse injection device 12, the cooling water attached to and entrained on the steel material M is blown away by reverse injection. Subsequently, the air blowing device 13 blows off the residual adhering water with high-pressure air, and the surface of the steel material is dried.
仕上圧延機１の出側と水切り装置１１の出側に、それぞ
れ仕上温度検出器！４と焼入終了温度検出器１５が設置
されている。■は仕上温度測定点であり、仕上温度検出
器１４が設はされる。■は急冷後の鋼材の表面温度を測
定するための測定点で、急冷ラインの最終端から１〜２
ｍ＠れた位置である。温度検出器１４．１５は非接触式
温度計、たとえば放射温度計である。測定点（ゆには焼
入終了温度検出器が設置される。Finishing temperature detectors are installed on the exit side of the finishing rolling mill 1 and the exit side of the draining device 11, respectively! 4 and a quenching end temperature detector 15 are installed. 2 is a finishing temperature measurement point, and a finishing temperature detector 14 is installed. ■ is the measurement point for measuring the surface temperature of the steel material after quenching, 1 to 2 points from the final end of the quenching line.
m@ position. The temperature detector 14.15 is a non-contact thermometer, for example a radiation thermometer. A quenching end temperature detector is installed at the measuring point (Yuyu).
第２図は本発明における低温靭性の優れた圧延鋼材製造
のための急冷ライン直後から１〜２ｍ離れたΔＩＩＩ定
点（りにおける鋼材温度の最適範囲を示すものである。FIG. 2 shows the optimum range of steel material temperature at a ΔIII fixed point located 1 to 2 m away from immediately after the quenching line for producing rolled steel products with excellent low-temperature toughness in the present invention.
急冷ラインの長さは、下記の条件式により求めることが
最良の結果をもたらす。これは、本発明の目的を達成す
るため本発明者等の実験により確められている。The best result is obtained by determining the length of the quenching line using the following conditional expression. This has been confirmed through experiments conducted by the inventors in order to achieve the purpose of the present invention.
Ｌ ＝ ０．９−ｄ ２−Ｖ （９，８−０，９ＨＬ
ｎ Ｑ ） ＋ Ｋ・・・（２）
ここて、
Ｌ：急冷長さく＋＋ｎ） ｄ：鋼材径（■）■＝圧
延速度（ｍ／ｓ） Ｑ：冷却水ｆｉｔ（ｍ３／ｈｒ）
Ｋ：補正係数 −４０００〜＋２０００ｍｍ（２）式の
ｄ２・Ｖは体積速度（生産量）を表わし、ｄ２・Ｖが増
加すれば急冷長さしは長くなる。L = 0.9-d 2-V (9,8-0,9HL
n Q ) + K... (2) Here, L: Quenching length ++n) d: Steel diameter (■) ■ = Rolling speed (m/s) Q: Cooling water fit (m3/hr)
K: Correction coefficient -4000 to +2000 mm d2·V in equation (2) represents the volumetric velocity (production amount), and as d2·V increases, the quenching length increases.
また、冷却本縫Ｑが増加すれば、急冷長しは短かくてす
むことになる。また、補正係数には圧延鋼材の機械的性
質が所望のレベルになるための許容範囲を示すもので、
通常−４０００〜＋２０００ｍｍであるか、望ましくは
Ｏ〜−１０００＋ｍａ＋である。（３）式は水噴射急冷
ラインで使用する水量の下限を決定するものて、中位伝
熱面積に噴射する水量、すなわち水量密度を２００ＬＩ
Ｉ：１７６１１２以上望ましくは２５０ｍ：ｌ／ｈｍ２
以上として、鋼材周方向の冷却ムラを防止し、品質バラ
ツキを目標範囲に入れるための基準を示すものである。Furthermore, if the cooling lockstitch Q increases, the quenching length can be shortened. In addition, the correction factor indicates the allowable range for the mechanical properties of rolled steel to reach the desired level.
It is usually -4000 to +2000 mm, preferably O to -1000+ma+. Equation (3) determines the lower limit of the amount of water used in the water injection quenching line, and the amount of water injected to the medium heat transfer area, that is, the water amount density, is 200LI.
I: 176112 or more preferably 250m:l/hm2
The above describes standards for preventing uneven cooling of steel materials in the circumferential direction and for bringing quality variations within the target range.
次に、上記のように構成された装置により鋼材を表面焼
入する方法について説明する。Next, a method for surface hardening a steel material using the apparatus configured as described above will be described.
第３図は上記装置による鋼材の冷却曲線（クーリングパ
ターン）の−例を示した線図である。鋼材に冷却水を噴
射した時の鋼材から冷却水への熱伝達率は、鋼材径方向
内部への熱伝達率より大きくなるように冷却される。従
って、第３図に示すように１表面温度は冷却開始から急
激に低下する。FIG. 3 is a diagram showing an example of a cooling curve (cooling pattern) of steel material by the above-mentioned apparatus. When cooling water is injected onto the steel material, the steel material is cooled so that the heat transfer coefficient from the steel material to the cooling water is greater than the heat transfer coefficient to the inside of the steel material in the radial direction. Therefore, as shown in FIG. 3, the surface temperature rapidly decreases from the start of cooling.
冷却装置の構成は、水切り装２１１１を急冷ライン４の
最後部に設置し、鋼材の直径によって急冷開始位置を変
えて急冷長さを調整し、急冷開始位置がいつも水切り装
置直前になるようにするとよい。The configuration of the cooling device is such that the draining device 2111 is installed at the rear end of the quenching line 4, and the quenching start position is changed depending on the diameter of the steel material to adjust the quenching length, so that the quenching start position is always immediately before the draining device. good.
急冷ライン前の鋼材表面温度は、加熱炉の抽出温度を制
御して通常８２０±２０℃に保持される。急冷後の測定
点■の鋼材温度制御のみて靭性の優れた鋼材を製造する
には前記条件式（１）の範囲内て４えられる温度まで急
冷することで達成される。The surface temperature of the steel material before the quenching line is normally maintained at 820±20° C. by controlling the extraction temperature of the heating furnace. In order to manufacture a steel material with excellent toughness only by controlling the temperature of the steel material at the measurement point ① after quenching, this can be achieved by rapidly cooling the steel material to a temperature within the range of conditional expression (1).
（１）式は圧延鋼材の機械的性質を所望の範囲におさめ
るために、急冷ライン最後の冷却端から１〜２ｍ離れた
測定点■での鋼材温度を規定するものである。また、直
線Ａ、Ｂを表わす式中に急冷終了後経過時間ｔを取り込
んでいるのは、圧延速度による０点までの到達時間を補
正する考えからである。たとえば同一直径の鋼材て冷却
パターンを同じにしても、圧延速度か遅くなれば、０点
での鋼材は急冷終了後経過時間ｔか長くなるので、鋼材
温度は高くなることになる。ここて直線Ｂは鋼材表層の
焼戻しマルテンサイト組織の厚みを許容範囲内で極力厚
くして、抗張力とシャルピー（ｉｆｆを増加させるため
の限界を示すものであり、この範囲を超えた場合には伸
びが低下し、所要の鋼材特性か得られない。また直ｍＡ
はその逆の限界を示すもので、伸びを十分大きくして、
抗張力とシャルピー値か許容下限になるようにした条件
式である。Equation (1) defines the temperature of the steel material at the measurement point 1, which is 1 to 2 m away from the last cooling end of the quenching line, in order to keep the mechanical properties of the rolled steel material within a desired range. Furthermore, the reason why the elapsed time t after the end of quenching is incorporated into the equations representing the straight lines A and B is to correct the time required to reach the zero point depending on the rolling speed. For example, even if the cooling pattern is the same for steel materials of the same diameter, if the rolling speed becomes slower, the elapsed time t after the end of rapid cooling of the steel material at point 0 will become longer, so the temperature of the steel material will become higher. Here, straight line B indicates the limit for increasing the tensile strength and Charpy (if) by increasing the thickness of the tempered martensitic structure on the surface layer of the steel material as much as possible within the allowable range. decreases, making it impossible to obtain the required steel properties.Also, the direct mA
indicates the opposite limit; if the elongation is made sufficiently large,
This is a conditional expression in which the tensile strength and Charpy value are within the allowable lower limit.
（作用）
条件式（２）、（３）から与えられる急冷長さで表面焼
入れされた鋼材は急冷ラインの末端から１〜２ｍ＃れた
０点で鋼材温度の測定が行われる。０点の鋼材温度が条
件式（１）で与えられる範囲内にあるように冷却水駿を
制御して低温靭性の優れた圧延鋼材を製造する。急冷時
間を決めて０点の鋼材温度を目標範囲に制御することに
より、その後の鋼材温度履歴は内部の熱伝導のみで決ま
ることになり、結果として、従来の復熱温度測定点＠の
温度レベルを目標温度にコントロールしていることにな
る。従って鋼材表層の焼戻しマルテンサイト組織の厚み
を目標通りに制御していることになり、安定して靭性の
優れた圧延鋼材を製造できる。また、急冷長さを与える
条件式（２）、（３）と急冷直後の０点の目標温度を与
える条件式（１）て圧延鋼材を制御する場合は、現在の
圧延鋼材から次の圧延鋼材への情報伝達か早くなり、不
具合か生じた場合の改善のためのアクションか早くなり
、同−鋼材内ての冷却水量制御もフィードバック制御で
容易に実施することかできる。(Operation) The steel material temperature is measured at a point 0 located 1 to 2 m from the end of the quenching line for the steel material that has been surface hardened with the quenching length given by conditional expressions (2) and (3). A rolled steel material with excellent low-temperature toughness is manufactured by controlling the flow of cooling water so that the steel material temperature at point 0 is within the range given by conditional expression (1). By determining the quenching time and controlling the steel material temperature at point 0 within the target range, the subsequent steel material temperature history is determined only by internal heat conduction, and as a result, the temperature level at the conventional recuperation temperature measurement point @ This means that the temperature is controlled to the target temperature. Therefore, the thickness of the tempered martensitic structure in the surface layer of the steel material is controlled as desired, and rolled steel products with excellent toughness can be stably produced. In addition, when controlling rolled steel using conditional expressions (2) and (3) that give the quenching length and conditional expression (1) that gives the target temperature at the 0 point immediately after quenching, it is necessary to Information transmission to the steel is faster, actions for improvement can be taken faster when a problem occurs, and the amount of cooling water within the same steel can be easily controlled using feedback control.
（実施例） 次に本発明による実施例を示す。(Example) Next, examples according to the present invention will be shown.
第３図に示すクーリングパターンは、鋼種３．５ｚＮｉ
鋼、仕上温度０点での鋼材温度８２０℃１鋼材直径ｄ
： ：１８ｍｍφ、仕上速度Ｖ ： ２．２ＩＩｌ／ｓ
、冷却水量Ｑ： ３８０ｍゴ／ｈｒとして、急冷長さＬ
を（１）式から算出した約１０ｍを使用して表面焼入れ
した場合の例である。The cooling pattern shown in Figure 3 is for steel type 3.5zNi.
Steel, steel temperature at finishing temperature 0 point 820℃ 1 steel diameter d
: :18mmφ, finishing speed V : 2.2IIl/s
, Cooling water amount Q: 380mgo/hr, quenching length L
This is an example of surface hardening using approximately 10 m calculated from equation (1).
ライン温度計１５で鋼材温度を測定した結果、冷却水逆
噴射装置１２の後端から約１．６ ｍ離れた０点での温
度は約２５０℃となり、第２図に示す目標温度範囲２１
０〜３２５℃（ｔ ／ ｒ ２坤Ｏ，ＳＳ）を十分満足
しており、低温靭性の優れた圧延鋼材の製造かできた。As a result of measuring the steel material temperature with the line thermometer 15, the temperature at the 0 point, which is approximately 1.6 m away from the rear end of the cooling water reverse injection device 12, was approximately 250°C, which was within the target temperature range 21 shown in Fig. 2.
The temperature of 0 to 325°C (t/r 2K, SS) was fully satisfied, and a rolled steel material with excellent low-temperature toughness could be produced.
（発り１の効果）
急冷ライン直後の（の点て鋼材温度か（３）式の直ｉＡ
、Ｂて求められる範囲内にあるようにすることのみて冷
却水量を制御するのて、圧延中に不具合か生した場合の
同−鋼材内および次の圧延鋼材への４片のためのアクシ
ョンかｖくなり、安定して低温靭性の優れた圧延鋼材の
製造が可能になると共に、生産量の増加および歩留り向
上にもつながる。(Effect of origin 1) Is the temperature of the steel material immediately after the quenching line (iA) calculated by equation (3)?
By controlling the amount of cooling water to ensure that it is within the range required by ,B, if a problem occurs during rolling, what action should be taken for the same steel material and the next rolled steel material? This makes it possible to stably manufacture rolled steel materials with excellent low-temperature toughness, and also leads to an increase in production and an improvement in yield.
第１図はこの発明の方法を実施するだめの実施態様を示
す説明図、第２図は所望の鋼材特性を得るための急冷ラ
イン直後１〜２ｍ＠れた場所ての目標温度を示す線図、
第３図は鋼材の冷却曲線の一例を示す線図である。
ｌ・・・仕上圧延機、３・・・冷却装δ、４・・・急冷
ライン、５・・・復熱ライン、７・・・冷却箱、１１・
・・水切り装置、１２・・・冷却水逆噴射装置、１３・
・・空気吹付装置、】４・・・仕上温度検出器、 ｔＳ
−・・焼入終了温度検出器、２１・・・巻取機。
出願人代理人 弁理士 矢葺知之（ほか１名）。、っ
漿−羽一一一七叩≦ ε憬Fig. 1 is an explanatory diagram showing an embodiment of the method of the present invention, and Fig. 2 is a diagram showing the target temperature at a distance of 1 to 2 m immediately after the quenching line to obtain the desired steel properties. ,
FIG. 3 is a diagram showing an example of a cooling curve of steel material. 1... Finishing rolling mill, 3... Cooling device δ, 4... Rapid cooling line, 5... Recuperation line, 7... Cooling box, 11...
・・Water draining device, 12・・Cooling water reverse injection device, 13・
...Air blowing device, ]4...Finishing temperature detector, tS
-...Quenching end temperature detector, 21... Winding machine. Patent attorney Tomoyuki Yabuki (and one other person) representing the applicant. ,
Serum - Feather 117 hits ≦ ε憬
Claims (1)
過せしめることにより、表層部を下記条件の範囲内で与
えられる温度まで急冷し、次いで復熱ラインにおいて内
部保有熱により表層部を復熱せしめることを特徴とする
低温靭性の優れた圧延鋼材の製造方法。 〔条件〕 １４５・ｔ／ｒ＾２＋１３０≦Ｔ≦１５２・ｔ／ｒ＾２
＋２４０ ｔ：急冷終了から測定位置［ｂ］までの経過時間（ｈｒ
） ｒ：鋼材の半径（ｍ） Ｔ：急冷後冷却ラインから１〜２ｍ離れた場所で測定す
る温度（℃）[Claims] The surface layer is rolled to a predetermined diameter size and then passed through a quenching line to rapidly cool the surface layer to a temperature given within the range of the following conditions, and then in a recuperation line the surface layer is A method for producing a rolled steel material with excellent low-temperature toughness, characterized by reheating the part. [Condition] 145・t/r^2+130≦T≦152・t/r^2
+240 t: Elapsed time from the end of rapid cooling to measurement position [b] (hr
) r: Radius of steel material (m) T: Temperature measured at a location 1 to 2 m away from the cooling line after quenching (°C)
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8418386A JPS62240721A (en) | 1986-04-14 | 1986-04-14 | Production of rolled steel products having excellent low-temperature toughness |
| CA000521775A CA1265421A (en) | 1985-10-31 | 1986-10-30 | Method and apparatus for cooling rolled steels |
| US06/924,816 US4786338A (en) | 1985-10-31 | 1986-10-30 | Method for cooling rolled steels |
| AU64661/86A AU587652B2 (en) | 1985-10-31 | 1986-10-31 | Method and apparatus for cooling rolled steels |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8418386A JPS62240721A (en) | 1986-04-14 | 1986-04-14 | Production of rolled steel products having excellent low-temperature toughness |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62240721A true JPS62240721A (en) | 1987-10-21 |
| JPH0215605B2 JPH0215605B2 (en) | 1990-04-12 |
Family
ID=13823365
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8418386A Granted JPS62240721A (en) | 1985-10-31 | 1986-04-14 | Production of rolled steel products having excellent low-temperature toughness |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62240721A (en) |
-
1986
- 1986-04-14 JP JP8418386A patent/JPS62240721A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0215605B2 (en) | 1990-04-12 |
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