JPS63161117A - Production of hot rolled steel products having high strength and high toughness - Google Patents
Production of hot rolled steel products having high strength and high toughnessInfo
- Publication number
- JPS63161117A JPS63161117A JP31047586A JP31047586A JPS63161117A JP S63161117 A JPS63161117 A JP S63161117A JP 31047586 A JP31047586 A JP 31047586A JP 31047586 A JP31047586 A JP 31047586A JP S63161117 A JPS63161117 A JP S63161117A
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- range
- toughness
- tempered
- steel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 56
- 239000010959 steel Substances 0.000 title claims abstract description 56
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 14
- 229910000734 martensite Inorganic materials 0.000 claims abstract description 26
- 229910001562 pearlite Inorganic materials 0.000 claims abstract description 14
- 239000002344 surface layer Substances 0.000 claims abstract description 14
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 14
- 229910001563 bainite Inorganic materials 0.000 claims abstract description 11
- 238000005098 hot rolling Methods 0.000 claims abstract description 10
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 239000000463 material Substances 0.000 claims description 9
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 8
- 229910052742 iron Inorganic materials 0.000 claims description 4
- 238000001816 cooling Methods 0.000 abstract description 24
- 238000005496 tempering Methods 0.000 abstract description 15
- 238000000034 method Methods 0.000 abstract description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 6
- 229910052799 carbon Inorganic materials 0.000 abstract description 3
- 239000013078 crystal Substances 0.000 abstract description 3
- 238000007670 refining Methods 0.000 abstract description 3
- 230000000717 retained effect Effects 0.000 abstract 2
- 229910000975 Carbon steel Inorganic materials 0.000 abstract 1
- 239000010962 carbon steel Substances 0.000 abstract 1
- 238000010791 quenching Methods 0.000 description 19
- 230000000171 quenching effect Effects 0.000 description 16
- 230000000694 effects Effects 0.000 description 9
- 238000005096 rolling process Methods 0.000 description 6
- 238000003303 reheating Methods 0.000 description 5
- 229910000760 Hardened steel Inorganic materials 0.000 description 4
- 229910001566 austenite Inorganic materials 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000001376 precipitating effect Effects 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 229910000954 Medium-carbon steel Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 210000003739 neck Anatomy 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は高強度高靭性熱間圧延鋼材の製造方法に関し、
詳しくは、圧延後に再加熱し、焼入れ焼戻し処理するこ
とを要せずして、圧延後に直接焼入れを施すと共に、自
己焼戻しさせることによって、熱間圧延ままにて高強度
高靭性を有せしめた圧延鋼材、特に圧延棒鋼の製造方法
に関する。[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for producing high-strength, high-toughness hot-rolled steel materials,
Specifically, it is a rolled product that has high strength and high toughness as hot rolled by directly quenching and self-tempering after rolling without the need for reheating, quenching and tempering after rolling. The present invention relates to a method for manufacturing steel materials, particularly rolled steel bars.
（従来の技術）
中炭素棒鋼及び中炭素低合金熱間圧延棒鋼は、機械構造
用鋼として軸頚、ボルト、ナツト類等の製造に広く用い
られている。これらの棒鋼は、従来、再加熱後、焼入れ
焼戻しする調質処理を施して製造されているが、近年、
省エネルギーや省工程のために、熱間圧延後の調質処理
を省略するために、熱間圧延後、直接焼入れして、熱間
圧延ままで高強度高靭性を有する棒鋼を製造する方法が
開発されている。(Prior Art) Medium carbon steel bars and medium carbon low alloy hot rolled steel bars are widely used as machine structural steels for manufacturing shaft necks, bolts, nuts, etc. Conventionally, these steel bars have been manufactured by subjecting them to reheating followed by quenching and tempering, but in recent years,
In order to save energy and process, a method has been developed in which steel bars with high strength and high toughness are manufactured as hot rolled by directly quenching after hot rolling in order to omit tempering treatment after hot rolling. has been done.
例えば、「鉄と綱」第１３巻第７０号第２５６頁には、
圧延棒鋼の表面のみをＭ８点以下に冷却し、表層部が焼
戻しマルテンサイト、中心部がフェライト・パーライト
組織である直接焼入れ圧延棒鋼を製造する方法が記載さ
れている。また、特開昭５９−８９７１６号公報には、
低炭素鋼又は低炭素低合金鋼を９００℃以上の仕上温度
から直接焼入れし、又はこの直接焼入れの後に、４５０
℃以下の温度で焼戻し処理して、耐遅れ破壊性にすぐれ
た強靭網を製造する方法が記載されている。For example, in "Tetsu to Tsuna" Volume 13, No. 70, Page 256,
A method is described in which only the surface of the rolled steel bar is cooled to the M8 point or lower to produce a directly quenched rolled steel bar in which the surface layer is tempered martensite and the center has a ferrite-pearlite structure. Also, in Japanese Patent Application Laid-Open No. 59-89716,
Direct quenching of low carbon steel or low carbon low alloy steel from a finishing temperature of 900°C or higher, or after this direct quenching, 450°C
A method for producing a tough mesh with excellent delayed fracture resistance by tempering at a temperature of 0.degree. C. or lower is described.
（発明の目的）
しかし、本発明者らは、非調質圧延棒鋼の製造について
鋭意研究した結果、上記した従来の方法とは異なり、圧
延後に所定の温度から所定の温度まで水冷して、直接焼
入れすると共に、この冷却終了後に内部保有熱によって
所定の条件下に自己焼戻しさせることによって、表層部
が焼戻しマルテンサイト、中心部が焼戻しマルテンサイ
ト、ベイナイト及び／又は過冷フェライト・パーライト
組織を有して、圧延ままで一層高強度高靭性を有する圧
延棒鋼を得ることができることを見出して、本発明に至
ったものである。(Purpose of the Invention) However, as a result of intensive research into the production of non-thermal rolled steel bars, the present inventors discovered that, unlike the above-mentioned conventional method, the steel bars are directly cooled by water cooling from a predetermined temperature to a predetermined temperature after rolling. By quenching and self-tempering under predetermined conditions using internal heat after cooling, the surface layer has tempered martensite, and the center has tempered martensite, bainite, and/or supercooled ferrite/pearlite structure. The inventors have discovered that it is possible to obtain a rolled steel bar with even higher strength and toughness in the as-rolled state, leading to the present invention.
従って、本発明は、再加熱して焼入れ焼戻しする調質処
理を要せずして、強度及び靭性が一層改善された圧延鋼
材、特に圧延棒鋼を製造する方法を提供することを目的
とする。Therefore, an object of the present invention is to provide a method for producing rolled steel materials, particularly rolled steel bars, which have further improved strength and toughness without requiring reheating, quenching, and tempering.
（発明の構成）
本発明による高強度高靭性熱間圧延鋼材の製造方法は、
重量％で
Ｃ０．２０〜０．６０％、
Ｓｉ０．１０〜０．３５％、
Ｍｎ ０．３０〜１．８０％、
／ｌ！ ０．０１０〜０．０４５％、Ｎ ０
．００５〜０．０２０％、残部鉄及び不可避的不純物よ
りなる鋼片を仕上温度Ａ３〜Ａｚ＋１５０℃の範囲で熱
間圧延した後、５０℃以上であって、且つ、Ｍ５点以下
の範囲の温度まで急冷して、表面温度が１００〜６００
℃の範囲となるように内部保有熱を有せしめ、自己焼戻
しさせて、表層部が焼戻しマルテンサイト組織、中心部
が焼戻しマルテンサイト、ベイナイト及び／又は過冷フ
ェライト・パーライト組織を主たる組織として有せしめ
ることを特徴とする。(Structure of the Invention) The method for producing a high-strength, high-toughness hot-rolled steel material according to the present invention includes:
In weight%, C0.20-0.60%, Si0.10-0.35%, Mn 0.30-1.80%, /l! 0.010-0.045%, N0
．． After hot rolling a steel billet consisting of 005~0.020%, balance iron and unavoidable impurities at a finishing temperature in the range of A3~Az+150°C, it is rolled to a temperature in the range of 50°C or higher and below the M5 point. Rapid cooling to a surface temperature of 100 to 600
℃ range, and self-tempering, so that the surface layer has a tempered martensite structure and the center has a tempered martensite, bainite, and/or supercooled ferrite/pearlite structure as the main structure. It is characterized by
先ず、本発明において用いる鋼における化学成分につい
て説明する。First, the chemical components of the steel used in the present invention will be explained.
Ｃは、得られる棒鋼に所要の強度を付与するために添加
される。添加量が０．２０％よりも少ないときは、焼入
れ棒鋼として所要の強度を得ることができない。特に、
好ましいＣの添加量は０．３０％以上である。しかし、
過多に添加するときは、鋼の靭性を低下させ、また、焼
き割れを生じさせるので、添加量の上限は０．６０％と
する。C is added to impart the required strength to the resulting steel bar. When the amount added is less than 0.20%, the required strength as a hardened steel bar cannot be obtained. especially,
The preferred amount of C added is 0.30% or more. but,
When added in excess, the toughness of the steel decreases and quench cracking occurs, so the upper limit of the amount added is 0.60%.
Ｓｔは、脱酸剤として０．１０％以上を添加することが
必要であるが、０．３５％を越えて多量に添加しても、
脱酸効果が飽和するのみならず、経済的にも不利である
ので、添加量は０．１０〜０．３５％の範囲とする。It is necessary to add 0.10% or more of St as a deoxidizing agent, but even if it is added in a large amount exceeding 0.35%,
Since the deoxidizing effect is not only saturated but also economically disadvantageous, the amount added is in the range of 0.10 to 0.35%.
Ｍｎは、焼入れ性を向上させ、鋼の強度及び靭性を向上
させるために添加される。添加量が０．３０％よりも少
ないときは、焼入れ棒鋼として強度が不足する。特に、
本発明においては、Ｍｎは、０．５％を越える量にて添
加することが好ましい。Mn is added to improve hardenability and improve the strength and toughness of steel. When the amount added is less than 0.30%, the strength of the hardened steel bar is insufficient. especially,
In the present invention, Mn is preferably added in an amount exceeding 0.5%.
しかし、１．８０％を越えて過多に添加するときは、鋼
の靭性を低下させ、また、焼き割れを生じさせるので、
添加量の上限は１．８０％とする。However, if it is added in excess of 1.80%, it will reduce the toughness of the steel and cause quench cracking.
The upper limit of the amount added is 1.80%.
本発明において、Ａｌは、製鋼段階における脱酸と共に
、特に、微細な炭窒化物を析出して、圧延終了後のオー
ステナイト粒を整細粒化し一強度及び靭性を高める効果
を有する重要な合金元素である。かかる効果を有効に得
るためには、少なくとも０．０１％を添加することが必
要である。しかし、過多に添加するときは、介在物量が
増加し、却って靭性を低下させるので、添加量の上限は
０゜０４５％とする。In the present invention, Al is an important alloying element that has the effect of deoxidizing in the steelmaking stage and, in particular, precipitating fine carbonitrides, refining austenite grains after rolling, and improving strength and toughness. It is. In order to effectively obtain such an effect, it is necessary to add at least 0.01%. However, when adding too much, the amount of inclusions increases and the toughness is reduced, so the upper limit of the amount added is set at 0°045%.
Ｎは、微細なＡｌの窒化物を安定して形成させ、かくし
て、圧延終了後のオーステナイト粒を整細粒化するため
に重要な元素であって、かかる効果を安定して有効に得
るためには、少なくとも０．００５％を添加することが
必要である。しかし、０゜０２０％を越えて過多に添加
するときは、鋼の脆化を招（。N is an important element for stably forming fine Al nitrides and thus refining the austenite grains after rolling, and in order to stably and effectively obtain this effect. It is necessary to add at least 0.005%. However, when added in excess of 0.020%, it causes embrittlement of the steel.
本発明においては、鋼には上記した元素に加えて、Ｃｒ
及びＭｏよりなる群から選ばれる少なくとも１種の元素
を添加してもよい。これらの元素も、いずれも焼入れ性
を向上させて、強度を高めると共に、靭性を向上させる
効果を有する。しかし、過多に添加しても、この効果が
飽和して、経済的に不利であるので、Ｃｒについては１
．５０％以下、ＭＯについては０．３０％以下の範囲で
添加される。In the present invention, in addition to the above-mentioned elements, the steel contains Cr.
At least one element selected from the group consisting of and Mo may be added. These elements also have the effect of improving hardenability, increasing strength, and improving toughness. However, even if too much Cr is added, this effect will be saturated and it will be economically disadvantageous.
．． It is added in an amount of 50% or less, and MO is added in an amount of 0.30% or less.
本発明においては、上記した元素と共に、又は別に、Ｎ
ｂ及びＴｉよりなる群から選ばれる少なくとも１種の元
素を添加してもよい。これらの元素は、ＡＮと同様に、
炭窒化物を微細に析出させ、オーステナイト粒度の調整
に有効である。このような効果を有効に得るためには、
Ｎｂについては０．０１５％以上、また、Ｔｉについて
も０．０１５％以上添加される。過多に添加しても、効
果が飽和するのみならず、経済的にも不利である。In the present invention, N
At least one element selected from the group consisting of b and Ti may be added. These elements, like AN,
It is effective for finely precipitating carbonitrides and adjusting austenite grain size. In order to effectively obtain such effects,
Nb is added in an amount of 0.015% or more, and Ti is added in an amount of 0.015% or more. Adding too much will not only saturate the effect but also be economically disadvantageous.
本発明による高強度高靭性圧延鋼材の製造方法は、上記
したような化学成分を有する鋼片を熱間圧延終了後、Ａ
、乃至Ａ３＋１５０℃の範囲の温度から、５０℃以上で
あって、且つ、Ｍ３点以下の範囲の温度まで急冷した後
、自己焼戻しさせて、表層が焼戻しマルテンサイト組織
、中心部が焼入れ組織としての焼戻しマルテンサイト、
ベイナイト及び／又は過冷フェライト・パーライト組織
を主たる組織として有せしめるものである。In the method for producing high-strength, high-toughness rolled steel materials according to the present invention, after hot rolling a steel billet having the above-mentioned chemical composition,
, to A3+150°C, to a temperature of 50°C or higher and below the M3 point, and then self-tempered to form a tempered martensitic structure in the surface layer and a quenched structure in the center. tempered martensite,
The main structure is bainite and/or supercooled ferrite/pearlite structure.
本発明の方法において、鋼片の熱間圧延は、通常の方法
によればよいが仕上温度は、本発明の方法においては、
Ａ、乃至Ａｆｆ＋１５０℃の範囲の温度とし、この冷却
開始温度から、５０℃以上であって、且つ、Ｍ５点以下
の範囲の温度まで急冷して直接焼入れし、且つ、この直
接焼入れにおいては、冷却停止後、棒鋼の表面温度を１
００〜６００℃の範囲の温度とする内部保有熱を棒鋼が
有するように、冷却を制御することが肝要である。In the method of the present invention, the hot rolling of the steel billet may be carried out by a normal method, but the finishing temperature in the method of the present invention is as follows:
The temperature is in the range of A to Aff + 150°C, and direct quenching is performed by rapid cooling from this cooling start temperature to a temperature in the range of 50°C or higher and below the M5 point, and in this direct quenching, cooling After stopping, reduce the surface temperature of the steel bar to 1
It is important to control the cooling so that the steel bar has internal heat retention to a temperature in the range of 00-600°C.
上記冷却開始温度がＡ：ｌよりも低い場合は、初析フェ
ライトが発生して、均一なマルテンサイト組織を得るこ
とができない。また、冷却開始温度がＡｚ＋１５０℃よ
りも高い場合は、結晶粒が粗大化し、靭性が劣化する。If the cooling start temperature is lower than A:l, pro-eutectoid ferrite is generated, making it impossible to obtain a uniform martensitic structure. Moreover, when the cooling start temperature is higher than Az+150° C., the crystal grains become coarse and the toughness deteriorates.
他方、冷却停止温度は、５０℃以上であって、且つ、Ｍ
、以下の温度の範囲である。前述したように、本発明の
方法においては、この直接焼入れの後、圧延棒鋼の有す
る内部保有熱によって自己焼戻しさせることによって、
棒鋼の表層部に焼戻しマルテンサイト、中心部に焼戻し
マルテンサイト、ベイナイト及び／又は過冷フェライト
・パーライト組織を有せしめるために、冷却停止温度は
、冷却後の棒鋼が内部保有熱にて自己焼戻しし得るよう
に、５０℃以上であることが必要である。また、冷却停
止温度の上限は、直接焼入れによってマルテンサイト組
織を得るために、Ｍ、点温度である。On the other hand, the cooling stop temperature is 50°C or higher, and M
, in the following temperature ranges: As mentioned above, in the method of the present invention, after this direct quenching, self-tempering is performed using the internal heat possessed by the rolled steel bar.
In order to have tempered martensite in the surface layer of the steel bar and tempered martensite, bainite, and/or supercooled ferrite/pearlite structure in the center, the cooling stop temperature is set so that the steel bar after cooling is self-tempered by internal heat. The temperature must be 50° C. or higher to obtain the desired temperature. Further, the upper limit of the cooling stop temperature is M, a point temperature in order to obtain a martensitic structure by direct quenching.
更に、上記のように直接焼入れ後に、棒鋼が１００〜６
００℃の範囲の表面温度を有することが必要とされる理
由は次のとおりである。即ち、表面温度が１００℃より
も低いときは、焼き割れが発生すると共に、靭性が不足
することとなる。他方、６００℃よりも高い温度では、
中心部の組織がフェライト・パーライトとなって、焼入
れ棒鋼として使用することができないからである。Furthermore, as mentioned above, after direct quenching, the steel bar has a hardness of 100 to 6
The reason why it is necessary to have a surface temperature in the range of 00°C is as follows. That is, when the surface temperature is lower than 100° C., quench cracking occurs and toughness is insufficient. On the other hand, at temperatures higher than 600°C,
This is because the structure in the center becomes ferrite/pearlite and cannot be used as a hardened steel bar.
上記のような冷却条件の制御は、実操業においては、冷
却停止温度と組織との関係を実験によって求め、冷却に
用いる水量と水冷時間を選択することによって行なうこ
とができる。In actual operation, the cooling conditions can be controlled as described above by determining the relationship between the cooling stop temperature and the structure through experiments, and selecting the amount of water used for cooling and the water cooling time.
（発明の効果）
以上のようにして、本発明の方法によって得られる棒鋼
は、特に、Ａ１とＮとを含有し、前述したように、整細
粒の状態から直接焼入れされるので、結晶組織が微細で
あり、且つ、表層部が焼戻しマルテンサイト、中心部が
焼戻しマルテンサイト、ベイナイト及び／又は過冷フェ
ライト・パーライトを主要組織として有し、従って、再
加熱、焼入れ焼戻し処理を要せずして、圧延ままにて調
質鋼と同等又はそれ以上に高強度高靭性を有し、また、
表層部は焼戻しマルテンサイト組織を有するが、内部が
フェライト・パーライト組織である表面焼入れ棒鋼に比
べて、靭性に一層すぐれる。(Effects of the Invention) As described above, the steel bar obtained by the method of the present invention contains A1 and N in particular, and as described above, it is directly quenched from a fine-grained state, so the crystal structure is The surface layer has tempered martensite, and the center has tempered martensite, bainite, and/or supercooled ferrite/pearlite as its main structure, so it does not require reheating or quenching and tempering. As rolled, it has high strength and toughness equivalent to or higher than tempered steel, and
Although the surface layer has a tempered martensitic structure, it has better toughness than a surface-hardened steel bar that has a ferrite/pearlite structure inside.
（実施例）
以下に実施例を挙げて本発明を説明するが、本発明は、
これら実施例によって何ら限定されるものではない。(Example) The present invention will be described below with reference to Examples.
The present invention is not limited in any way by these examples.
実施例１
第１表に示す化学成分を有する鋼片を加熱した後、棒鋼
に熱間圧延し、この後、圧延ライン中にて第２表に示す
冷却開始温度及び冷却停止温度にて直接焼入れし、第２
表に示す温度にて自己焼戻しした。尚、冷却条件は、冷
却に用いた水量と水冷時間にて示す。Example 1 After heating a steel billet having the chemical composition shown in Table 1, it was hot rolled into a steel bar, and then directly quenched in a rolling line at the cooling start temperature and cooling stop temperature shown in Table 2. And the second
Self-tempering was performed at the temperature shown in the table. Note that the cooling conditions are indicated by the amount of water used for cooling and the water cooling time.
鋼記号Ａ及びＢは、本発明の方法による棒鋼であり、Ｃ
及びＤは直接焼入れ開始温度が高く、且つ、自己焼戻し
温度が高い比較鋼である。また、比較鋼Ｅは通常の圧延
棒鋼をオフラインにて再加熱し、焼入れ焼戻し処理を施
して得たものである。Steel symbols A and B are steel bars manufactured by the method of the present invention, and C
and D are comparative steels that have a high direct quenching start temperature and a high self-tempering temperature. Comparative steel E was obtained by reheating a normal rolled steel bar off-line and subjecting it to quenching and tempering treatment.
第３表にこのようにして得たそれぞれの棒鋼について、
そのＤ／２部（Ｄは棒鋼直径である。）の機械的性質と
共に、Ｄ／８部及びＤ／２部（中心部）におけるオース
テナイト結晶粒度番号、及び表層部及びＤ／２部におけ
る硬さと主要組織を示す。Table 3 shows each steel bar obtained in this way.
Along with the mechanical properties of the D/2 part (D is the steel bar diameter), the austenite grain size number in the D/8 part and D/2 part (center part), and the hardness in the surface layer part and the D/2 part. Indicates the main organization.
本発明の方法による棒鋼は、表層部に焼戻しマルテンサ
イト、中心部に焼戻しマルテンサイト、ベイナイト又は
過冷フェライト・パーライトを主要組織として有し、中
心部まで焼入れされていることが明らかである。また、
従来鋼Ｅと同一強度で比較するとき、伸び、絞り、衝撃
値にすぐれている。他方、比較ｌｉＤは、中心部まで焼
入れされていないので、本発明鋼に比べて靭性が劣るこ
とが明らかである。It is clear that the steel bar obtained by the method of the present invention has tempered martensite in the surface layer, tempered martensite, bainite, or supercooled ferrite/pearlite in the center, and is hardened to the center. Also,
When compared with conventional steel E at the same strength, it has excellent elongation, reduction of area, and impact value. On the other hand, since the comparative LiD is not hardened to the center, it is clear that the toughness is inferior to the steel of the present invention.
Claims (4)
３〜Ａ＿３＋１５０℃の範囲で熱間圧延した後、５０℃
以上であって、且つ、Ｍ＿Ｓ点以下の範囲の温度まで急
冷して、表面温度が１００〜６００℃の範囲となるよう
に内部保有熱を有せしめ、自己焼戻しさせて、表層部が
焼戻しマルテンサイト組織、中心部が焼戻しマルテンサ
イト、ベイナイト及び／又は過冷フェライト・パーライ
ト組織を主たる組織として有せしめることを特徴とする
高強度高靭性熱間圧延鋼材の製造方法。(1) C0.20-0.60%, Si0.10-0.35%, Mn0.30-1.80%, Al0.010-0.045%, N0.005-0.020% in weight% , Finishing temperature A_
After hot rolling in the range of 3~A_3+150℃, 50℃
above, and is rapidly cooled to a temperature in the range below the M_S point to have internal heat so that the surface temperature is in the range of 100 to 600°C, and self-tempered, so that the surface layer part becomes tempered martensite. 1. A method for producing a high-strength, high-toughness hot-rolled steel material, characterized in that the main structure is tempered martensite, bainite, and/or supercooled ferrite/pearlite structure in the center.
、 残部鉄及び不可避的不純物よりなる鋼片を仕上温度Ａ＿
３〜Ａ＿３＋１５０℃の範囲で熱間圧延した後、５０℃
以上であって、且つ、Ｍ＿Ｓ点以下の範囲の温度まで急
冷して、表面温度が１００〜６００℃の範囲となるよう
に内部保有熱を有せしめ、自己焼戻しさせて、表層部が
焼戻しマルテンサイト組織、中心部が焼戻しマルテンサ
イト、ベイナイト及び／又は過冷フェライト・パーライ
ト組織を主たる組織として有せしめることを特徴とする
高強度高靭性熱間圧延鋼材の製造方法。(2) In weight% (a) C0.20-0.60%, Si0.10-0.35%, Mn0.30-1.80%, Al0.010-0.045%, N0.005-0 and (b) at least one element selected from the group consisting of Cr 1.50% or less and Mo 0.30% or less, with the balance consisting of iron and inevitable impurities. Temperature A_
After hot rolling in the range of 3~A_3+150℃, 50℃
above, and is rapidly cooled to a temperature in the range below the M_S point to have internal heat so that the surface temperature is in the range of 100 to 600°C, and self-tempered, so that the surface layer part becomes tempered martensite. 1. A method for producing a high-strength, high-toughness hot-rolled steel material, characterized in that the main structure is tempered martensite, bainite, and/or supercooled ferrite/pearlite structure in the center.
、 残部鉄及び不可避的不純物よりなる鋼片を仕上温度Ａ＿
３〜Ａ＿３＋１５０℃の範囲で熱間圧延した後、５０℃
以上であって、且つ、Ｍ＿Ｓ点以下の範囲の温度まで急
冷して、表面温度が１００〜６００℃の範囲となるよう
に内部保有熱を有せしめ、自己焼戻しさせて、表層部が
焼戻しマルテンサイト組織、中心部が焼戻しマルテンサ
イト、ベイナイト及び／又は過冷フェライト・パーライ
ト組織を主たる組織として有せしめることを特徴とする
高強度高靭性熱間圧延鋼材の製造方法。(3) In weight% (a) C0.20-0.60%, Si0.10-0.35%, Mn0.30-1.80%, Al0.010-0.045%, N0.005-0 and (b) at least one element selected from the group consisting of 0.015% or more Nb and 0.015% or more Ti, with the balance consisting of iron and inevitable impurities at a finishing temperature. A_
After hot rolling in the range of 3~A_3+150℃, 50℃
above, and is rapidly cooled to a temperature in the range below the M_S point to have internal heat so that the surface temperature is in the range of 100 to 600°C, and self-tempered, so that the surface layer part becomes tempered martensite. 1. A method for producing a high-strength, high-toughness hot-rolled steel material, characterized in that the main structure is tempered martensite, bainite, and/or supercooled ferrite/pearlite structure in the center.
し、 残部鉄及び不可避的不純物よりなる鋼片を仕上温度Ａ＿
３〜Ａ＿３＋１５０℃の範囲で熱間圧延した後、５０℃
以上であって、且つ、Ｍ＿Ｓ点以下の範囲の温度まで急
冷して、表面温度が１００〜６００℃の範囲となるよう
に内部保有熱を有せしめ、自己焼戻しさせて、表層部が
焼戻しマルテンサイト組織、中心部が焼戻しマルテンサ
イト、ベイナイト及び／又は過冷フェライト・パーライ
ト組織を主たる組織として有せしめることを特徴とする
高強度高靭性熱間圧延鋼材の製造方法。(4) In weight% (a) C0.20-0.60%, Si0.10-0.35%, Mn0.30-1.80%, Al0.010-0.045%, N0.005-0 (b) at least one element selected from the group consisting of Cr 1.50% or less and Mo 0.30% or less; (c) Nb 0.015% or more, Ti 0.015% or more A steel piece containing at least one element selected from the group consisting of: iron and unavoidable impurities is heated to a finishing temperature of A_
After hot rolling in the range of 3~A_3+150℃, 50℃
above, and is rapidly cooled to a temperature in the range below the M_S point to have internal heat so that the surface temperature is in the range of 100 to 600°C, and self-tempered, so that the surface layer part becomes tempered martensite. 1. A method for producing a high-strength, high-toughness hot-rolled steel material, characterized in that the main structure is tempered martensite, bainite, and/or supercooled ferrite/pearlite structure in the center.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31047586A JPS63161117A (en) | 1986-12-24 | 1986-12-24 | Production of hot rolled steel products having high strength and high toughness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31047586A JPS63161117A (en) | 1986-12-24 | 1986-12-24 | Production of hot rolled steel products having high strength and high toughness |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63161117A true JPS63161117A (en) | 1988-07-04 |
| JPH0219175B2 JPH0219175B2 (en) | 1990-04-27 |
Family
ID=18005690
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31047586A Granted JPS63161117A (en) | 1986-12-24 | 1986-12-24 | Production of hot rolled steel products having high strength and high toughness |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63161117A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63145714A (en) * | 1986-12-09 | 1988-06-17 | Nhk Spring Co Ltd | Production of steel materials for spring |
| JPH0551698A (en) * | 1991-03-26 | 1993-03-02 | Sumitomo Metal Ind Ltd | Steel for bolt and nut excellent in fire-resistance |
| JPH05195141A (en) * | 1991-08-27 | 1993-08-03 | Japan Casting & Forging Corp | Forged steel product having excellent fire resistance and toughness and its manufacture |
| JP2007100193A (en) * | 2005-10-07 | 2007-04-19 | Topy Ind Ltd | Method for manufacturing roller shell in carrier at lower part of construction machine |
| JP2011006771A (en) * | 2008-07-11 | 2011-01-13 | Sanyo Special Steel Co Ltd | Cooling method for preventing quenched crack at quenching time while shifting bar steel |
| JP2017115230A (en) * | 2015-12-25 | 2017-06-29 | Ｊｆｅスチール株式会社 | Steel material and method for producing the same |
-
1986
- 1986-12-24 JP JP31047586A patent/JPS63161117A/en active Granted
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63145714A (en) * | 1986-12-09 | 1988-06-17 | Nhk Spring Co Ltd | Production of steel materials for spring |
| JPH0551698A (en) * | 1991-03-26 | 1993-03-02 | Sumitomo Metal Ind Ltd | Steel for bolt and nut excellent in fire-resistance |
| JPH05195141A (en) * | 1991-08-27 | 1993-08-03 | Japan Casting & Forging Corp | Forged steel product having excellent fire resistance and toughness and its manufacture |
| JP2007100193A (en) * | 2005-10-07 | 2007-04-19 | Topy Ind Ltd | Method for manufacturing roller shell in carrier at lower part of construction machine |
| WO2007043307A1 (en) * | 2005-10-07 | 2007-04-19 | Topy Kogyo Kabushiki Kaisha | Process for manufacturing roller shell of lower running body of construction machine |
| JP2011006771A (en) * | 2008-07-11 | 2011-01-13 | Sanyo Special Steel Co Ltd | Cooling method for preventing quenched crack at quenching time while shifting bar steel |
| JP2017115230A (en) * | 2015-12-25 | 2017-06-29 | Ｊｆｅスチール株式会社 | Steel material and method for producing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0219175B2 (en) | 1990-04-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4018905B2 (en) | Hot rolled wire rod and bar for machine structure and manufacturing method thereof | |
| US4946516A (en) | Process for producing high toughness, high strength steel having excellent resistance to stress corrosion cracking | |
| JP3554505B2 (en) | Hot-rolled wire rod / steel bar for machine structure and manufacturing method thereof | |
| CN112877591B (en) | High-strength and high-toughness hardware tool and steel for chain and manufacturing method thereof | |
| JPS63286517A (en) | Manufacture of high-tensile steel with low yielding ratio | |
| JPH05320749A (en) | Production of ultrahigh strength steel | |
| JPH039168B2 (en) | ||
| JPS63161117A (en) | Production of hot rolled steel products having high strength and high toughness | |
| JPS6286125A (en) | Production of hot rolled steel products having high strength and high toughness | |
| JPS6137334B2 (en) | ||
| JPS6383249A (en) | Hot working tool steel and its manufacture | |
| JP2000336460A (en) | Hot rolled wire rod and steel bar for machine structure and manufacture of the same | |
| JPH08199310A (en) | Production of high strength martensitic stainless steel member | |
| JPH04358023A (en) | Production of high strength steel | |
| JPH04371547A (en) | Production of high strength and high toughness steel | |
| JPH0813028A (en) | Production of precipitation hardening steel material having high tensile strength and high toughness | |
| JPS6137333B2 (en) | ||
| JP2756535B2 (en) | Manufacturing method for strong steel bars | |
| JPH04297548A (en) | High strength and high toughness non-heat treated steel and its manufacture | |
| JPH0470385B2 (en) | ||
| JP2767254B2 (en) | Method for producing Cr-Mo case hardened steel | |
| JPH0229727B2 (en) | DORIRUKARAAYOBOKONOSEIZOHOHO | |
| JPS6156268A (en) | High toughness and high tensile steel and its manufacture | |
| JPS61166919A (en) | Manufacture of unrefined warm-forged article having high toughness | |
| JPH10280036A (en) | Wire rod for high strength bolt excellent in strength and ductility and its production |