JP2864997B2 - Manufacturing method of high strength and high toughness steel pipe - Google Patents
Manufacturing method of high strength and high toughness steel pipeInfo
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- JP2864997B2 JP2864997B2 JP23035494A JP23035494A JP2864997B2 JP 2864997 B2 JP2864997 B2 JP 2864997B2 JP 23035494 A JP23035494 A JP 23035494A JP 23035494 A JP23035494 A JP 23035494A JP 2864997 B2 JP2864997 B2 JP 2864997B2
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- steel pipe
- strength
- toughness
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- steel
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Description
【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【０００１】[0001]
【産業上の利用分野】この発明は、自動車等に使用され
る機械構造用鋼材のうち、特に自動車の足まわりに使用
される高強度部材に適した高強度高靭性鋼管の製造方法
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high-strength and high-toughness steel pipe suitable for high-strength members used around a vehicle, among steel materials for machine structures used in automobiles and the like.
【０００２】[0002]
【従来の技術】現在、自動車の駆動系ならびに足まわり
に使用される鋼材の中で、特にステアリングシャフト、
ドライブシャフト等には、引張強さ８０ｋｇｆ／ｍｍ2
クラスのＪＩＳ Ｇ４０５１に規定の機械構造用炭素鋼
鋼材のＳ４５Ｃ、Ｓ５０Ｃ等の棒鋼が多く使用され、表
面高周波焼入れ、焼戻しされて使用されている。しかし
ながら、自動車の軽量化が進む中で、駆動系ならびに足
まわりに使用される鋼材も中空鋼管化が強く要望され
る。ステアリングシャフト、ドライブシャフト等を中空
化する場合、現状の引張強さ８０ｋｇｆ／ｍｍ2クラス
の機械構造用炭素鋼のＳ４５Ｃ、Ｓ５０Ｃ等の棒鋼に比
べ、中空分だけ更に高強度で、かつ高靭性の鋼管が要求
されると共に、表面高周波焼入れ、焼戻しされるため、
表面高周波焼入れされた部材として、硬さのみならず、
高いねじり強度と良好な曲げ特性が要求される。2. Description of the Related Art At present, among steel materials used for driving systems and undercarriages of automobiles, especially steering shafts,
The drive shaft has a tensile strength of 80 kgf / mm 2
Many bar steels such as S45C and S50C of carbon steel materials for machine structures specified in JIS G4051 of the class are used, and are subjected to surface induction hardening and tempering. However, as automobiles are becoming lighter, there is a strong demand for hollow steel pipes for steel materials used for drive trains and suspensions. If you hollowed steering shaft, a drive shaft or the like, the tensile strength of current 80 kgf / mm 2 class of machine structural carbon steel S45C, compared with steel bars such as S50C, a further high strength by the hollow component, and the high toughness Since steel pipe is required and surface induction hardening and tempering,
As a surface induction hardened member, not only hardness,
High torsional strength and good bending properties are required.
【０００３】このため、自動車の足まわりに使用される
高強度、高靭性の継目無鋼管は、熱間にて継目無製管さ
れた管を単に焼入れ、焼戻し熱処理を施して高強度化す
るのみでは不十分であり、熱間にて継目無製管された管
を冷間加工し、所定の寸法精度を確保したのち熱処理を
施し、高強度化と高靭性化を図ることが試みられてい
る。[0003] For this reason, a high-strength, high-toughness seamless steel pipe used around a vehicle's undercarriage is simply obtained by simply quenching a hot-sealed pipe and performing a tempering heat treatment to increase the strength. It is not enough, and it is attempted to cold-work a pipe that has been made seamlessly in the hot state, perform heat treatment after securing predetermined dimensional accuracy, and achieve high strength and high toughness. .
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、熱間に
て継目無製管された管を冷間加工したのち熱処理を施
し、高強度化と高靭性化を図るのみでは、特にステアリ
ングシャフト、ドライブシャフト等に使用される引張強
さ８０ｋｇｆ／ｍｍ2クラスの機械構造用炭素鋼のＳ４
５Ｃ、Ｓ５０Ｃ等の棒鋼の強度以上の高強度、高靭性を
付与することは不可能である。However, if the seamless pipe is cold-worked while hot and then subjected to heat treatment to achieve high strength and high toughness, particularly, the steering shaft and the drive shaft are required. tensile strength are used to equal 80 kgf / mm 2 class of carbon steel for mechanical structure S4
It is impossible to impart high strength and high toughness higher than the strength of steel bars such as 5C and S50C.
【０００５】本発明者らは、高周波焼入れ前の素材特性
に優れた高強度、高靭性鋼管の製造方法として、Ｃ：
０．３５〜０．５５％、Ｓｉ：０．１０〜０．５０％、
Ｍｎ：１．０〜２．０％、Ｐ：０．０３％以下、Ｓ：
０．０３％以下と、Ｃｒ：１．０％以下、Ｖ：０．２％
以下、Ｎｂ：０．０１５〜０．０５％、Ｂ：０．００１
０〜０．００５０％のうちの１種または２種以上を含有
し、残部がＦｅおよび不可避的不純物からなる鋼材を用
いて継目無鋼管を、製管時に仕上げ温度Ａｒ3変態点以
上で最終圧延したのち、断面減少率１０〜７０％で冷間
加工して所定の寸法に仕上げ、ついで５００〜７００℃
の温度で熱処理を行うことを特徴とする高強度高靭性鋼
管の製造方法を既に特願平５−１９２８８５号として特
許出願している。この特願平５−１９２８８５号に開示
の方法は、高強度高靭性鋼管を得ることができるが、後
工程での高周波焼入れ特性については不十分であること
が判明した。The present inventors have proposed a method for producing a high-strength, high-toughness steel pipe having excellent material properties before induction hardening, as follows:
0.35 to 0.55%, Si: 0.10 to 0.50%,
Mn: 1.0 to 2.0%, P: 0.03% or less, S:
0.03% or less, Cr: 1.0% or less, V: 0.2%
Hereinafter, Nb: 0.015 to 0.05%, B: 0.001
Contain one or two or more of 0 to 0.0050%, the final rolling in the remainder of the seamless steel pipe using a steel consisting of Fe and unavoidable impurities, the finish during pipe-temperature Ar 3 transformation point or more After that, it is cold worked at a reduction rate of 10 to 70% and finished to a predetermined size, and then 500 to 700 ° C.
A method for producing a high-strength, high-toughness steel pipe characterized by performing a heat treatment at the temperature described above has already been filed as a patent application as Japanese Patent Application No. 5-192885. According to the method disclosed in Japanese Patent Application No. 5-192885, a high-strength and high-toughness steel pipe can be obtained, but it has been found that the induction hardening characteristics in the subsequent steps are insufficient.
【０００６】この発明の目的は、自動車の足まわりに使
用される高強度部材に適した高周波焼入れ特性に優れた
高強度高靭性鋼管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 of manufacturing a high-strength, high-toughness steel pipe excellent in induction hardening characteristics suitable for a high-strength member used around a vehicle.
【０００７】[0007]
【課題を解決するための手段】本発明者らは、上記目的
を達成すべく高周波焼入れ条件を種々試験検討した結
果、９００〜１０００℃の高周波焼入れを行うことによ
って、現行のＳ４５Ｃ、Ｓ５０Ｃ等の棒鋼よりもねじり
強度ならびに曲げ特性の優れた高強度高靭性鋼管を製造
できることを確認し、この発明に到達した。The present inventors have conducted various tests and examinations on the induction hardening conditions to achieve the above-mentioned object. As a result, by performing induction hardening at 900 to 1000 ° C., the present S45C, S50C, etc. It has been confirmed that a high-strength, high-toughness steel pipe having better torsional strength and bending characteristics than a bar can be manufactured, and the present invention has been achieved.
【０００８】すなわちこの発明は、Ｃ：０．３５〜０．
５５％、Ｓｉ：０．１０〜０．５０％、Ｍｎ：１．０〜
２．０％、Ｐ：０．０３％以下、Ｓ：０．０３％以下
と、Ｃｒ：１．０％以下、Ｖ：０．２％以下、Ｎｂ：
０．０１５〜０．０５％、Ｔｉ：０．０１０〜０．０５
％、Ｂ：０．００１０〜０．００５０％のうちの１種ま
たは２種以上を含有し、残部がＦｅおよび不可避的不純
物からなる鋼材を用いて継目無鋼管を製管する際、仕上
げ温度Ａｒ3変態点以上で最終圧延したのち、断面減少
率１０〜７０％で冷間加工して所定の寸法に仕上げ、つ
いで５００〜７００℃の温度で熱処理を行い、さらに９
００〜１０００℃の温度範囲で表面高周波焼入れ後、焼
戻しを行うことを特徴とする高強度高靭性鋼管の製造方
法である。That is, according to the present invention, C: 0.35-0.
55%, Si: 0.10 to 0.50%, Mn: 1.0 to
2.0%, P: 0.03% or less, S: 0.03% or less, Cr: 1.0% or less, V: 0.2% or less, Nb:
0.015 to 0.05%, Ti: 0.010 to 0.05
%, B: when producing a seamless steel pipe using a steel material containing one or more of 0.0010 to 0.0050% and the balance being Fe and unavoidable impurities, the finishing temperature Ar After the final rolling at three transformation points or more, cold working is performed at a cross-sectional reduction rate of 10 to 70% to finish it to a predetermined size, and then heat treatment is performed at a temperature of 500 to 700 ° C.
This is a method for producing a high-strength, high-toughness steel pipe, wherein tempering is performed after surface induction hardening in a temperature range of 00 to 1000 ° C.
【０００９】[0009]
【作用】この発明において、素材の化学成分の限定理由
は、下記の通りである。Ｃは素材の強度、歯切り部の高
周波焼入れ後の強度を得るために必要な元素で、０．３
５％未満では目標の硬度が得られず、また、０．５５％
を超えると硬度が高くなり靭性が悪化するため、０．３
５〜０．５５％とした。Ｓｉは鋼の脱酸のために重要な
元素で、０．１０％未満では脱酸が不十分となり、ま
た、０．５０％を超えると効果が飽和し、高価となるた
め、０．１０〜０．５０％とした。Ｍｎは素材の強度、
延性、靭性の確保に重要な元素で、１．０％未満では目
標とする機械的特性が得られず、また、２．０％を超え
ると靭性の低下を来すため、１．０〜２．０％とした。
Ｐは焼入れ後の靭性を悪化させる元素で、０．０３％を
超えると靭性が低下するので、０．０３％以下とした。
Ｓは非金属介在物のＭｎＳを生成させ、靭性を悪化させ
る元素で、０．０３％を超えるとその傾向が著しいの
で、０．０３％以下とした。In the present invention, the reasons for limiting the chemical components of the material are as follows. C is an element necessary for obtaining the strength of the material and the strength after induction hardening of the gear cutting portion.
If it is less than 5%, the target hardness cannot be obtained, and 0.55%
Exceeds 0.3, the hardness increases and the toughness deteriorates.
5 to 0.55%. Si is an important element for deoxidizing steel. If it is less than 0.10%, deoxidation becomes insufficient. If it exceeds 0.50%, the effect is saturated and the cost becomes high. 0.50%. Mn is the strength of the material,
It is an important element for ensuring ductility and toughness. If it is less than 1.0%, the target mechanical properties cannot be obtained, and if it exceeds 2.0%, the toughness decreases. 0.0%.
P is an element that deteriorates the toughness after quenching, and if it exceeds 0.03%, the toughness is reduced.
S is an element that generates MnS as a nonmetallic inclusion and deteriorates toughness. When the content exceeds 0.03%, the tendency is remarkable, so that S is set to 0.03% or less.
【００１０】Ｃｒは素材の強度を得るのに重要な元素で
あるが、高価なため、１．０％以下とした。Ｖは素材の
強度ならびに靭性の確保に有効な元素であるが、高価な
ため０．２％以下とした。Ｎｂは素材の強度ならびに結
晶粒微細化による靭性の向上に有効な元素で、０．０１
５％未満ではその効果が十分でなく、また、０．０５０
％を超えると靭性が悪化するため、０．０１５〜０．０
５０％とした。Ｔｉは結晶粒の微細化による靭性の向上
に有効な元素で、０．０１０％未満ではその効果が十分
でなく、また、０．０５０％を超えると靭性が悪化する
ため、０．０１０〜０．０５０％とした。Ｂは高周波焼
入れ部の焼入れ性ならびに粒界強化による靭性の向上に
有効な元素で、０．００１０％未満ではその効果が十分
でなく、また、０．００５０％を超えると靭性が悪化す
るため、０．００１０〜０．００５０％とした。[0010] Although Cr is an important element for obtaining the strength of the material, it is expensive, so that the content is set to 1.0% or less. V is an element that is effective for securing the strength and toughness of the material, but is expensive, so it was set to 0.2% or less. Nb is an element effective for improving the strength of the material and toughness by refining the crystal grains.
If it is less than 5%, the effect is not sufficient.
%, The toughness deteriorates.
50%. Ti is an element effective for improving the toughness by refining the crystal grains. If the content is less than 0.010%, the effect is insufficient, and if it exceeds 0.050%, the toughness deteriorates. 0.050%. B is an element effective for improving the hardenability of the induction hardened portion and the toughness by strengthening the grain boundary. If the content is less than 0.0010%, the effect is not sufficient, and if it exceeds 0.0050%, the toughness deteriorates. 0.0010 to 0.0050%.
【００１１】熱間製管時の仕上げ温度をＡｒ3変態点以
上としたのは、圧延組織を整粒の組織とするためであ
る。また、冷間加工時の加工度を１０〜７０％としたの
は、１０％未満では所定の寸法精度が得られず、また、
７０％を超えると冷間加工による割れが懸念されるから
である。さらに、冷間加工後の熱処理温度を７００〜５
００℃としたのは、７００℃を超えると所定の強度が得
られず、また、５００℃未満では高強度となりすぎて延
性、靭性が低下するからである。さらにまた、高周波焼
入れ条件として加熱温度を９００〜１０００℃としたの
は、９００℃未満では短時間急速加熱のため炭化物が十
分固溶できず、所定の焼入れ硬さが得られず、また、１
０００℃を超えると高強度となり過ぎ焼入れ部の靭性が
低下するからである。なお、焼戻し温度は、特に規定し
ないが、一般には１５０〜２００℃で実施される。ま
た、高周波の周波数を変えることにより焼入れ深さを変
えることが可能である。The reason why the finishing temperature at the time of hot pipe making is higher than the Ar 3 transformation point is to make the rolling structure a grain-sized structure. Further, the reason why the working ratio at the time of cold working is set to 10 to 70% is that if the working ratio is less than 10%, a predetermined dimensional accuracy cannot be obtained.
If it exceeds 70%, cracks due to cold working are concerned. Further, the heat treatment temperature after the cold working is set to 700 to 5
The reason why the temperature is set to 00 ° C. is that if the temperature exceeds 700 ° C., a predetermined strength cannot be obtained, and if the temperature is lower than 500 ° C., the strength becomes too high and the ductility and toughness decrease. Furthermore, the reason why the heating temperature is set to 900 to 1000 ° C. as the induction hardening condition is that if the temperature is lower than 900 ° C., the carbides cannot be sufficiently solid-dissolved due to rapid heating for a short time, so that a predetermined hardening hardness cannot be obtained.
If the temperature exceeds 000 ° C., the strength becomes too high, and the toughness of the quenched portion decreases. The tempering temperature is not particularly limited, but is generally performed at 150 to 200 ° C. Further, it is possible to change the quenching depth by changing the high frequency.
【００１２】この発明においては、Ｃ：０．３５〜０．
５５％、Ｓｉ：０．１０〜０．５０％、Ｍｎ：１．０〜
２．０％、Ｐ：０．０３％以下、Ｓ：０．０３％以下
と、Ｃｒ：１．０％以下、Ｖ：０．２％以下、Ｎｂ：
０．０１５〜０．０５％、Ｔｉ：０．０１０〜０．０５
０％、Ｂ：０．００１０〜０．００５０％のうちの１種
または２種以上を含有し、残部がＦｅおよび不可避的不
純物からなる鋼材を用いることによって、鋼材の強度、
延性、靭性が確保され、かつ、継目無鋼管を、製管時に
仕上げ温度Ａｒ３変態点以上で最終圧延するから、整粒
の組織が得られる。しかも、断面減少率１０〜７０％の
範囲で冷間加工して所定の寸法に仕上げたのち、５００
〜７００℃の温度で熱処理を行うから、継目無鋼管にス
テアリングシャフト、ドライブシャフト等に使用される
引張強さ８０ｋｇｆ／ｍｍ2クラスの強度が付与される
と共に、靭性、延性が確保されている。さらに９００〜
１０００℃の温度範囲で表面高周波焼入れ後、焼戻しを
行うことによって、所要の高いねじり強度と良好なねじ
り特性を有する高強度、高靭性鋼管を得ることができ、
ステアリングシャフト、ドライブシャフト等の中空鋼管
化が可能となり、自動車の軽量化を図ることができる。In the present invention, C: 0.35-0.
55%, Si: 0.10 to 0.50%, Mn: 1.0 to
2.0%, P: 0.03% or less, S: 0.03% or less, Cr: 1.0% or less, V: 0.2% or less, Nb:
0.015 to 0.05%, Ti: 0.010 to 0.05
0%, B: By using a steel material containing one or more of 0.0010 to 0.0050% and the balance being Fe and unavoidable impurities, the strength of the steel material is improved.
Since ductility and toughness are ensured, and the seamless steel pipe is finally rolled at a finishing temperature of Ar3 transformation point or higher during pipe making, a grain-sized structure is obtained. In addition, after cold working in a range of 10 to 70% in area reduction rate to finish to a predetermined size, 500
Since the heat treatment is performed at a temperature of about 700 ° C., the seamless steel pipe is provided with a tensile strength of 80 kgf / mm 2 class used for a steering shaft, a drive shaft and the like, and also has toughness and ductility. 900 ~
After performing surface induction hardening in a temperature range of 1000 ° C. and performing tempering, a high-strength, high-toughness steel pipe having required high torsion strength and good torsion characteristics can be obtained.
A hollow steel tube such as a steering shaft and a drive shaft can be used, and the weight of the automobile can be reduced.
【００１３】[0013]
実施例１ 真空溶解した表１に示す化学成分の鋼（鋼種Ｎｏ．１〜
１１は本発明鋼、鋼種Ｎｏ．１２〜１６は比較鋼）を溶
製したのち、外径３１．８ｍｍ、肉厚８．０ｍｍに熱間
圧延（ただし、Ａｒ3変態点以上の８３０℃で仕上げ）
して継目無鋼管となし、外径２３．０ｍｍ、肉厚６．０
ｍｍに冷間引抜き加工（断面減少率４６％）したのち、
ＪＩＳ Ｚ２２４１に規定の引張試験での引張強さ８５
ｋｇｆ／ｍｍ2の強度となる条件で熱処理を行ったもの
について、周波数２０ｋＨｚにて最高加熱温度８５０〜
１０５０℃で焼入れを行ったのち、１７０℃で１時間焼
戻しを行った鋼管について、継目無鋼管の試験片の一端
を固定し、他端にねじり荷重を加えるねじり試験により
ねじり強度と割れの有無を調査した。その結果を表２に
示す。なお、鋼種Ｎｏ．２の本発明鋼を６５０℃で熱処
理したものについて、最高加熱温度９２０℃、９８０℃
で焼入れを行った場合を本発明例として、また、鋼種Ｎ
ｏ．２の本発明鋼を８００℃、４００℃で熱処理したも
のについて、最高加熱温度９５０℃で焼入れを行った場
合および鋼種Ｎｏ．２の本発明鋼を６５０℃で熱処理し
たものについて、最高加熱温度１０５０℃で焼入れを行
った場合を比較例として、同様の試験を行った。その結
果を表２に併記して示す。Example 1 Steel of the chemical composition shown in Table 1 melted under vacuum (steel type Nos.
No. 11 is the steel of the present invention, steel type No. 12 to 16 are comparative steels) and then hot-rolled to an outer diameter of 31.8 mm and a wall thickness of 8.0 mm (however, finished at 830 ° C above the Ar 3 transformation point)
To make a seamless steel pipe, outer diameter 23.0mm, wall thickness 6.0
mm after cold drawing (section reduction rate 46%)
Tensile strength 85 in tensile test specified in JIS Z2241
Heat treatment was performed under the condition of strength of kgf / mm 2 , and the maximum heating temperature was 850 to 850 at a frequency of 20 kHz.
After quenching at 1050 ° C, the steel pipe which was tempered at 170 ° C for 1 hour was tested for torsional strength and cracks by a torsional test in which one end of a seamless steel pipe test piece was fixed and the other end was subjected to a torsional load. investigated. Table 2 shows the results. In addition, steel type No. No. 2 of the present invention heat-treated at 650 ° C., the maximum heating temperature was 920 ° C. and 980 ° C.
In the present invention, the case of quenching with
o. No. 2 of the present invention was heat-treated at 800 ° C. and 400 ° C., and was quenched at a maximum heating temperature of 950 ° C. The same test was performed for the steel of the invention No. 2 which had been heat-treated at 650 ° C., with the case where quenching was performed at the maximum heating temperature of 1050 ° C. as a comparative example. The results are shown in Table 2.
【００１４】[0014]
【表１】 [Table 1]
【００１５】[0015]
【表２】 [Table 2]
【００１６】表２に示すとおり、本発明例はいずれもね
じり強度が高く、しかもねじり試験における割れの発生
は皆無であったが、比較例はねじり強度が低いもの、さ
らにねじり試験における割れの発生が認められ、延性、
靭性が乏しいものであった。As shown in Table 2, all of the examples of the present invention had high torsional strength and no cracks were generated in the torsional test, whereas the comparative examples had low torsional strength and cracks were generated in the torsional test. , Ductility,
The toughness was poor.
【００１７】実施例２ 表１に示す化学成分の鋼のうち、鋼種Ｎｏ．２の本発明
鋼と鋼種Ｎｏ．１２の比較鋼から製造した外径２３．０
ｍｍ、肉厚６．０ｍｍの本発明鋼管１、２および比較鋼
管について、図１に示すとおり、長さ３００ｍｍの鋼管
１の中央外周部に幅２ｍｍ、深さ２ｍｍ、底部Ｒが１ｍ
ｍのノッチ２の加工を行い、その部分に１００ｋＨｚで
高周波焼入れし、１７０℃で１時間焼戻しを行ったの
ち、図２に示すとおり、ノッチ２を下にして鋼管１の中
央から両側に７５ｍｍ離れた位置を支え３、３に載せ、
その中央部に上部から押金具を当て、押込み量１５ｍｍ
押曲げる曲げ試験をそれぞれ２回行い、曲げ吸収エネル
ギーを求めた。その結果を原鋼管の熱処理温度、引張強
さと共に表３に示す。なお、図３に供試材のノッチ位置
からの硬さ分布を、図４（ａ）に本発明鋼管の三点曲げ
チャート例を、図４（ｂ）に比較鋼管の三点曲げチャー
ト例を示す。Example 2 Among steels having the chemical components shown in Table 1, steel type No. No. 2 of the present invention steel and steel type No. Outer diameter 23.0 manufactured from 12 comparative steels
As shown in FIG. 1, the steel pipes 1 and 2 of the present invention having a thickness of 6.0 mm and a thickness of 6.0 mm and a comparative steel pipe have a width of 2 mm, a depth of 2 mm, and a bottom R of 1 m at the central outer peripheral portion of the steel pipe 1 having a length of 300 mm.
After processing the notch 2 of m, induction hardening the portion at 100 kHz and tempering at 170 ° C. for 1 hour, as shown in FIG. Position on the support 3, 3
Press the metal fitting from the top to the center, and press in 15mm
Each bending test was performed twice to determine the bending energy absorbed. Table 3 shows the results together with the heat treatment temperature and tensile strength of the raw steel pipe. FIG. 3 shows the hardness distribution from the notch position of the test material, FIG. 4A shows an example of a three-point bending chart of the steel pipe of the present invention, and FIG. 4B shows an example of a three-point bending chart of the comparative steel pipe. Show.
【００１８】[0018]
【表３】 [Table 3]
【００１９】図３に示すとおり、鋼種Ｎｏ．２の本発明
鋼管は、鋼種Ｎｏ．１２の比較鋼管に比べ、焼入れ特性
が優れている。また、図４に示すとおり、鋼種Ｎｏ．２
の本発明鋼管は、鋼種Ｎｏ．１２の比較鋼管に比べ、ク
ラックの進展が小さく、靭性が著しく優れている。さら
に、表３に示すとおり、鋼種Ｎｏ．２の本発明鋼管は、
鋼種Ｎｏ．１２の比較鋼管に比べ、吸収エネルギーは
１．５〜１．７倍と良好な曲げ特性を示している。As shown in FIG. The steel pipe No. 2 of the present invention has a steel type No. The quenching characteristics are superior to the comparative steel pipe No. 12. Further, as shown in FIG. 2
The steel pipe of the present invention of steel type No. Compared to the comparative steel pipe No. 12, crack development is small and toughness is remarkably excellent. Further, as shown in Table 3, the steel type No. 2. The steel pipe of the present invention is
Steel type No. As compared with the comparative steel pipe No. 12, the absorbed energy is 1.5 to 1.7 times, indicating good bending characteristics.
【００２０】[0020]
【発明の効果】以上述べたとおり、この発明方法によれ
ば、高強度、高延性、高靭性化を図ることができ、特に
自動車の足まわりに使用される高強度部材の現行Ｓ４５
Ｃ棒鋼に比較し、中空鋼管化が可能となり、自動車の軽
量化を図ることができる。As described above, according to the method of the present invention, high strength, high ductility, and high toughness can be achieved.
Compared with C bar steel, hollow steel pipes can be used, and the weight of automobiles can be reduced.
【図１】ノッチ加工した曲げ試験片の形状を示すもの
で、（ａ）図は正面図、（ｂ）図は側面図である。1A and 1B show a shape of a notched bending test piece, wherein FIG. 1A is a front view and FIG. 1B is a side view.
【図２】曲げ試験方法の説明図である。FIG. 2 is an explanatory diagram of a bending test method.
【図３】実施例２における本発明鋼管１、２と比較鋼管
のノッチ位置からの距離と硬さとの関係を示すグラフで
ある。FIG. 3 is a graph showing a relationship between a distance from a notch position and hardness of steel pipes 1 and 2 of the present invention and a comparative steel pipe in Example 2.
【図４】実施例２における本発明鋼管２と比較鋼管の三
点曲げチャート例を示すもので、（ａ）図は本発明鋼管
２の場合、（ｂ）図は比較鋼管の場合である。4 shows an example of a three-point bending chart of the steel pipe 2 of the present invention and a comparative steel pipe in Example 2. FIG. 4 (a) shows the case of the present steel pipe 2 and FIG. 4 (b) shows the case of the comparative steel pipe.
１ 鋼管 ２ ノッチ ３ 支え 1 steel pipe 2 notch 3 support
Claims (1)
１０〜０．５０％、Ｍｎ：１．０〜２．０％、Ｐ：０．
０３％以下、Ｓ：０．０３％以下と、Ｃｒ：１．０％以
下、Ｖ：０．２％以下、Ｎｂ：０．０１５〜０．０５
％、Ｔｉ：０．０１０〜０．０５％、Ｂ：０．００１０
〜０．００５０％のうちの１種または２種以上を含有
し、残部がＦｅおよび不可避的不純物からなる鋼材を用
いて継目無鋼管を製管する際、仕上げ温度Ａｒ3変態点
以上で最終圧延したのち、断面減少率１０〜７０％で冷
間加工して所定の寸法に仕上げ、ついで５００〜７００
℃の温度で熱処理を行い、さらに９００〜１０００℃の
温度範囲で表面高周波焼入れ後、焼戻しを行うことを特
徴とする高強度高靭性鋼管の製造方法。1. C: 0.35 to 0.55%, Si: 0.
10 to 0.50%, Mn: 1.0 to 2.0%, P: 0.
03% or less, S: 0.03% or less, Cr: 1.0% or less, V: 0.2% or less, Nb: 0.015 to 0.05
%, Ti: 0.010 to 0.05%, B: 0.0010
Contain one or two or more of ～0.0050%, when the remainder to pipe producing a seamless steel pipe using a steel consisting of Fe and unavoidable impurities, the final rolling at the finishing temperature than the Ar 3 transformation point After that, it is cold-worked at a cross-sectional reduction rate of 10 to 70% and finished to a predetermined size, and then 500 to 700
A method for producing a high-strength and high-toughness steel pipe, comprising: performing heat treatment at a temperature of 900C and further performing surface induction quenching in a temperature range of 900 to 1000C and then tempering.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23035494A JP2864997B2 (en) | 1994-08-30 | 1994-08-30 | Manufacturing method of high strength and high toughness steel pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23035494A JP2864997B2 (en) | 1994-08-30 | 1994-08-30 | Manufacturing method of high strength and high toughness steel pipe |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0873938A JPH0873938A (en) | 1996-03-19 |
| JP2864997B2 true JP2864997B2 (en) | 1999-03-08 |
Family
ID=16906550
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23035494A Expired - Fee Related JP2864997B2 (en) | 1994-08-30 | 1994-08-30 | Manufacturing method of high strength and high toughness steel pipe |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2864997B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005116284A1 (en) * | 2004-05-07 | 2005-12-08 | Sumitomo Metal Industries, Ltd. | Seamless steel pipe and method for production thereof |
| CN103526117A (en) * | 2012-07-03 | 2014-01-22 | 广西柳工机械股份有限公司 | Non-quenched and tempered steel, engineering mechanical semiaxle manufactured by using same and manufacturing method of semiaxle |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104372239B (en) * | 2014-10-14 | 2017-01-18 | 山东钢铁股份有限公司 | Vanadium-nitrogen microalloyed high-strength phase-transformation induced plastic steel seamless pipe and preparation method thereof |
-
1994
- 1994-08-30 JP JP23035494A patent/JP2864997B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005116284A1 (en) * | 2004-05-07 | 2005-12-08 | Sumitomo Metal Industries, Ltd. | Seamless steel pipe and method for production thereof |
| US7316143B2 (en) | 2004-05-07 | 2008-01-08 | Sumitomo Metal Industries, Ltd. | Seamless steel tubes and method for producing the same |
| CN100500910C (en) * | 2004-05-07 | 2009-06-17 | 住友金属工业株式会社 | Seamless steel pipe and method for production thereof |
| CN103526117A (en) * | 2012-07-03 | 2014-01-22 | 广西柳工机械股份有限公司 | Non-quenched and tempered steel, engineering mechanical semiaxle manufactured by using same and manufacturing method of semiaxle |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0873938A (en) | 1996-03-19 |
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