JPH0463227A - Manufacture of hot rolled steel for resistance welded steel tube for reinforcing car body - Google Patents

Manufacture of hot rolled steel for resistance welded steel tube for reinforcing car body

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Publication number
JPH0463227A
JPH0463227A JP17511390A JP17511390A JPH0463227A JP H0463227 A JPH0463227 A JP H0463227A JP 17511390 A JP17511390 A JP 17511390A JP 17511390 A JP17511390 A JP 17511390A JP H0463227 A JPH0463227 A JP H0463227A
Authority
JP
Japan
Prior art keywords
steel
strength
hot
resistance welded
rolled 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
Application number
JP17511390A
Other languages
Japanese (ja)
Other versions
JPH0774382B2 (en
Inventor
Hiroto Tanabe
田邉 弘人
Kazumasa Yamazaki
一正 山崎
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Nippon Steel Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nippon Steel Corp filed Critical Nippon Steel Corp
Priority to JP2175113A priority Critical patent/JPH0774382B2/en
Publication of JPH0463227A publication Critical patent/JPH0463227A/en
Publication of JPH0774382B2 publication Critical patent/JPH0774382B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Abstract

PURPOSE:To provide a steel with high strength, high toughness and high ductility by subjecting steel stock in which the amt. of C is specified, the amounts of Mn, Si, Ti and N are regulated and a trace amt. of B is added to hot rolling and coiling it at a specified temp. CONSTITUTION:A steel contg., by weight, 0.15 to 0.25% C, <=1.5% Mn, <=0.5% Si, <=0.04% Ti, 0.0003 to 0.O035% B, <=0.0080% N and the balance Fe with inevitable impurities is used as stock. This steel is hot-rolled and is thereafter coiled at >=600 deg.C. If required, the above steel is incorporated with one or >=two kinds among <=0.5% Ni, <=0.5% Cr and <=0.5% Mo. In this way, a hot rolled steel which is the stock for a high strength resistance welded steel tube excellent in elongation and toughness, having about >=120kgf/mm<2> tensile strength and useful for reinforcing car bodies as well as in which working loads applied thereto when it is formed into a resistance welded steel tube are same as those applied to a conventional low strength material can be obtd.

Description

【発明の詳細な説明】 (産業上の利用分野) 本発明は特に高強度を必要とする車体補強用鋼管、例え
ば、自動車側面衝突時の運転者の安全性を確保するため
のドア補強用鋼管であるドアインパクトバー、あるいは
バンパー用芯材等の高強度を要求される車体補強電縫鋼
管用熱延鋼材の製造方法に関するものである。
Detailed Description of the Invention (Field of Industrial Application) The present invention relates to steel pipes for reinforcing car bodies that require particularly high strength, such as steel pipes for reinforcing doors to ensure the safety of drivers during side collisions of automobiles. The present invention relates to a method for manufacturing hot-rolled steel material for car body reinforcement electric resistance welded steel pipes that require high strength, such as door impact bars or core materials for bumpers.

(従来の技術) 自動車車体補強用部材、例えばインパクトビームとして
用いる材料には、衝突時の乗員の安全性確保のため、高
強度であることと同時に、衝突時に大きな塑性変形を受
けても破断を起こして急激に強度が低下することがない
ようにすること、そして、低温でもこの特性を確保する
ことが必要である。このように、強度、延性、低温靭性
は重要な特性である。
(Prior art) In order to ensure the safety of occupants in the event of a collision, materials used for automobile body reinforcing members, such as impact beams, must not only have high strength but also resist rupture even if subjected to large plastic deformation during a collision. It is necessary to ensure that the strength does not suddenly decrease due to this phenomenon, and to ensure this property even at low temperatures. Thus, strength, ductility, and low temperature toughness are important properties.

高強度な電縫鋼管の製造方法としては、特公昭56−4
6538号公報に記載された高張力電縫鋼管の製造方法
が知られている。該方法では、延性を確保するために焼
戻処理を施しており、一般に、焼入焼戻処理は鋼管の靭
性・延性の回復のために必要であった。しかし、焼戻処
理を施すと強度が大幅に低下するため、例えば120k
gf/−以上という高強度の鋼管を得るのは困難であっ
た。かかる高強度鋼管を得ようとする場合には、焼入ま
まで使用するのが好ましいが、この場合は靭性が劣化す
る。そこで、焼入ままで靭性を向上させようとすると、
低炭素化を図れば良いが、このときは焼入時の冷却速度
によって強度のバラツキがきわめて大きくなり実用性能
として問題が生じて(る。
As a manufacturing method for high-strength electric resistance welded steel pipes,
A method for manufacturing high-tensile resistance welded steel pipes is known, which is described in Japanese Patent No. 6538. In this method, tempering treatment is performed to ensure ductility, and generally, quenching and tempering treatment is necessary to restore the toughness and ductility of the steel pipe. However, when tempering is applied, the strength decreases significantly, so for example, 120k
It has been difficult to obtain a steel pipe with a high strength of gf/- or more. In order to obtain such a high-strength steel pipe, it is preferable to use the pipe as-quenched, but in this case the toughness deteriorates. Therefore, if you try to improve the toughness while still quenching,
It would be better to try to reduce carbon, but in this case, the variation in strength becomes extremely large depending on the cooling rate during quenching, causing problems in terms of practical performance.

(発明が解決しようとする課題) 本発明は、上述の如く、インパクトビーム用鋼管のよう
に高強度、高靭性、高延性が必要な鋼管を製造するに際
し低成分化し、焼入ままで使用するような場合において
、焼きが入りにくい、強度バラツキが大きいなどの問題
を解決するためになされたものである。
(Problems to be Solved by the Invention) As described above, the present invention aims at reducing the chemical composition of steel pipes that require high strength, high toughness, and high ductility, such as steel pipes for impact beams, and using the same as quenched. This was done in order to solve problems such as difficulty in hardening and large variations in strength in such cases.

(課題を解決するための手段) 本発明の要旨とするところは下記のとおりである。(Means for solving problems) The gist of the present invention is as follows.

(1)C: 0.15〜0.25%(重量%、以下同じ
)Mn≦1.5% Si≦1.5% Ti≦1.04% B : 0.0003〜0.0035%N≦0.008
0% を含有し、残部Feおよび不可避的不純物よりなる鋼を
素材とし、熱間圧延後600℃以上で巻取ることを特徴
とする車体補強電縫鋼管用熱延鋼材の製造方法。
(1) C: 0.15 to 0.25% (weight%, same below) Mn≦1.5% Si≦1.5% Ti≦1.04% B: 0.0003 to 0.0035% N≦ 0.008
1. A method for producing a hot-rolled steel material for car body reinforcement electric resistance welded steel pipes, which is made of steel containing 0% Fe and unavoidable impurities, and the method comprises hot rolling and then winding at 600°C or higher.

(2)C: 0.15〜0.25%(重量%、以下同じ
)Mn≦1.5% Si≦1.5% Ti≦1.04% B : 0.0003〜0.0035%N≦0.008
0% を含有し、さらに Ni≦0.5% Cr≦0.5% Mo≦1.5% の一種または二種以上を含有し、残部Febよび不可避
的不純物よりなる鋼を素材とし、熱間圧延後600℃以
上で巻取ることを特徴とする車体補強電縫鋼管用熱延鋼
材の製造方法。
(2) C: 0.15 to 0.25% (weight%, same below) Mn≦1.5% Si≦1.5% Ti≦1.04% B: 0.0003 to 0.0035% N≦ 0.008
0% and further contains one or more of Ni≦0.5%, Cr≦0.5%, Mo≦1.5%, and the remainder consists of Feb and unavoidable impurities. A method for producing a hot-rolled steel material for car body reinforcement electric resistance welded steel pipes, which comprises winding at 600° C. or higher after rolling.

(作用) 本発明は、上記課題を解決するためになされたもので、
成分・熱延条件を選定することにより、その後電縫管と
する際の造管性は従来の低強度網管と同等で、電縫鋼管
とした後に焼入処理を行なうことにより、良好な伸び・
靭性を示す高強度鋼管とすることができる熱延鋼材を提
供する。
(Operation) The present invention has been made to solve the above problems,
By selecting the composition and hot-rolling conditions, the pipe-formability when making ERW pipes is equivalent to that of conventional low-strength mesh pipes, and by quenching after making ERW pipes, good elongation and
Provided is a hot-rolled steel material that can be made into a high-strength steel pipe exhibiting toughness.

以下本発明における熱延綱材製造条件の限定理由につい
て述べる。
The reasons for limiting the hot-rolled steel manufacturing conditions in the present invention will be described below.

まず、成分系であるが、本発明は、最終製品の車体補強
用電縫鋼管の時点では焼入マルテンサイト組織による強
化をめざしたもので、焼入ままのマルテンサイト組織の
強度はC含有量によって決定される。これは変態の利用
により過飽和に導入される固溶C量が支配要因となって
いると考えられる。自動車車体補強用として好ましい1
20kgf/−以上の強度を確保するためには、第1図
に示すごとくCは0.15%以上が必要である。一方、
C量を増やしていくと延性の劣化が顕著となる。
First, regarding the component system, the present invention aims to strengthen the final product of the ERW steel pipe for car body reinforcement by a quenched martensitic structure, and the strength of the as-quenched martensitic structure depends on the C content. determined by This is thought to be due to the amount of solid solute C introduced into supersaturation through the use of transformation being a controlling factor. Preferable for reinforcing automobile bodies 1
In order to ensure a strength of 20 kgf/- or more, C must be 0.15% or more as shown in FIG. on the other hand,
As the amount of C increases, the deterioration of ductility becomes remarkable.

10%程度以上の伸びを確保するには、Cは0.25%
以下とすることが必要である。また第2図に炭素量に対
する焼入材の靭性を示す。C0,25%以下で靭性を高
く保つことができる。
To ensure growth of about 10% or more, C should be 0.25%.
It is necessary to do the following. Furthermore, Fig. 2 shows the toughness of the quenched material relative to the carbon content. Toughness can be maintained high at C0.25% or less.

以上のように本発明においては、炭素量の効果を詳細に
調べることにより0.15%≦C≦0.25%の範囲で
、焼入処理後に高強度と高靭性・高延性を達成すること
ができ、車体補強用鋼管とじて有効な特性が得られる。
As described above, in the present invention, by examining the effect of carbon content in detail, it is possible to achieve high strength, high toughness, and high ductility after quenching in the range of 0.15%≦C≦0.25%. This makes it possible to obtain properties that are effective as steel pipes for reinforcing car bodies.

Mnは綱のマルテンサイト変態温度を低下させ、焼入性
を向上させるとともに、焼入処理途中にて変態後のセル
フテンパーを回避し、強度を高く保つ効果を持つことが
できる元素である。ただし、Mnは、例えば電縫溶接に
て鋼管を製造する場合を想定すると溶接欠陥を生し易く
、その含有量は1.50%が上限である。
Mn is an element that lowers the martensitic transformation temperature of the steel, improves hardenability, and also has the effect of avoiding self-tempering after transformation during the hardening process and maintaining high strength. However, assuming that a steel pipe is manufactured by electric resistance welding, for example, Mn tends to cause welding defects, and the upper limit of its content is 1.50%.

Ni 、 Cr + MoはMnに比べ、非常に高価で
あるが、Mnの他にこれらNi 、 Cr 、 Moを
単独または複合添加すると、マルテンサイト変態温度を
低下させ、セルフテンパーを回避し、高強度化により効
果を発揮するものである。溶接性を確保するため上限は
それぞれ0.5%とする。
Ni, Cr + Mo are very expensive compared to Mn, but adding these Ni, Cr, and Mo alone or in combination in addition to Mn lowers the martensitic transformation temperature, avoids self-tempering, and provides high strength. It is effective by changing the In order to ensure weldability, the upper limit is 0.5% for each.

Siについては、Mnとともに電縫溶接にて鋼管を製造
する場合に、溶接部の健全性を維持するうえで非常に重
要な元素である。Siの上限は、溶接部にてペネトレー
ターと呼ばれる酸化物を形成しないようにするため0.
5%以下とする。Mn/Si比のバランスを、3〜10
とするのが望ましい。
Si, together with Mn, is a very important element in maintaining the integrity of the weld when manufacturing steel pipes by electric resistance welding. The upper limit of Si is set to 0.0 to prevent the formation of oxides called penetrators in the welding area.
5% or less. Balance the Mn/Si ratio from 3 to 10.
It is desirable to do so.

Bは、焼入性を飛躍的に向上させる元素で、本発明の網
種の場合、比較的低Cにてマルテンサイト分率90%以
上を得るため、B添加を特徴としているが、0.000
3%未満では、焼入性向上効果が得られず、また0、0
035%を超える場合は、コスト高になるばかりでなく
、表面疵や靭性劣化の原因となり易い。従って、Bの添
加は0.0003〜0.0035%とした。
B is an element that dramatically improves hardenability, and the mesh type of the present invention is characterized by the addition of B in order to obtain a martensite fraction of 90% or more at a relatively low C. 000
If it is less than 3%, the effect of improving hardenability cannot be obtained, and if it is 0,0
If it exceeds 0.035%, not only will the cost increase, but it will also likely cause surface flaws and toughness deterioration. Therefore, the amount of B added was 0.0003 to 0.0035%.

二〇Bの焼入性向上効果は、Nが0.003%以上存在
すると失われるので、このNの固定化の目的でTiの添
加を行う。添加するTiの量は0.04%を超えると疵
の発生、切削性の劣化等品質面でトラブルを生じ易く、
従ってTiは0.04%以下に規制する。
Since the hardenability improvement effect of 20B is lost when 0.003% or more of N is present, Ti is added for the purpose of fixing this N. If the amount of Ti added exceeds 0.04%, quality problems such as occurrence of scratches and deterioration of machinability are likely to occur.
Therefore, Ti is regulated to 0.04% or less.

尚、Nは不可避的に鋼中に存在し、BNを形成し、Bの
効果を軽減してしまう。そこで、Nは極力軽減するのが
望ましく、上限を0.0080%とする。
Note that N inevitably exists in steel, forms BN, and reduces the effect of B. Therefore, it is desirable to reduce N as much as possible, and the upper limit is set to 0.0080%.

次に、熱延条件の限定理由であるが、本発明において詳
細に巻取温度の検討を実施した結果、第3図に示す結果
が得られた。横軸は巻取温度、縦軸は熱延綱材より電縫
管とした後焼入処理を実施した場合の鋼管強度特性であ
り、600℃未満の巻取温度では、強度のバラツキが非
常に大きくなる。すべて同一成分で同一の焼入処理を実
施した場合の例で、焼きの充分入った場合の強度は、巻
取温度によらずほぼ一定であるものの、巻取温度が60
0℃未満では、部分的に焼入れ不十分な組織を形成し、
強度バラツキが大きく、高強度を安定して確保するため
には不適切である。逆に600℃以上の巻取温度では、
熱延鋼材段階で比較的均一で粗いフェライトパーライト
組織を形成しており、造管後焼きを入れた場合、充分な
焼きが入りバラツキの少ない強度特性が得られる。
Next, regarding the reason for limiting the hot rolling conditions, we conducted a detailed study of the coiling temperature in the present invention, and as a result, the results shown in FIG. 3 were obtained. The horizontal axis is the coiling temperature, and the vertical axis is the strength characteristics of steel pipes when ERW tubes are made from hot-rolled steel and then quenched. At a coiling temperature of less than 600°C, the strength varies greatly. growing. This is an example where all components are the same and the same hardening process is performed.The strength when hardened sufficiently is almost constant regardless of the winding temperature, but when the winding temperature is 60
Below 0°C, a partially insufficiently quenched structure is formed,
The strength variation is large, making it inappropriate for stably securing high strength. On the other hand, at a winding temperature of 600℃ or higher,
A relatively uniform and coarse ferrite-pearlite structure is formed at the hot-rolled steel stage, and when the tube is hardened after tube formation, sufficient hardening occurs and strength properties with little variation can be obtained.

さらに、熱延綱材を鋼管とする場合の造管性からも60
0℃以上の巻取温度とする。ここで、言う造管性という
のは、熱延綱材のハンドリングのしやすさ、成形のしや
すさ、電縫溶接のしやすさを指す。本発明の出発材は、
炭素量は極力軽減しているが、Bの添加等にて焼入性を
高くしているため、熱延の巻取温度の低温化にて容易に
高強度な熱延綱材が得られてしまう。高強度な調材にな
ると熱延鋼材から電縫管用調帯にするせん断加工の際の
刃物の寿命の短期化、巻取・巻き戻し力の上昇といった
ハンドリングの難しさ、材料の陳伏強度の上昇により成
形反力の増大、ハックリング量の増大による定型の困難
さ、成形の難しさと同時に電縫溶接品質に影響を及ぼす
電縫溶接給電部の形状不安定化を生じ溶接品質安定が難
しくなる。
Furthermore, from the viewpoint of pipe forming properties when hot-rolled steel pipes are made,
The winding temperature shall be 0°C or higher. Here, the pipe formability refers to the ease of handling, forming, and electric resistance welding of hot-rolled steel. The starting material of the present invention is
Although the carbon content is reduced as much as possible, the hardenability is increased by adding B, etc., so it is possible to easily obtain high-strength hot-rolled steel by lowering the hot-rolling temperature. Put it away. When it comes to preparing high-strength materials, the life of the cutter during the shearing process from hot-rolled steel to belts for ERW pipes is shortened, handling is difficult due to increased winding and unwinding force, and the strength of the material when folding increases. Due to the rise, the forming reaction force increases, the amount of hackling increases, making it difficult to form, and the shape of the ERW welding power supply part becomes unstable, which affects the ERW welding quality as well as the difficulty of forming, making it difficult to stabilize welding quality. .

これに対して巻取温度を600℃以上とすると、第4図
に示す如(一般の電縫鋼管の強度水準である40kg/
−から60kg/−程度の熱延綱材となり、通常の電I
ll管と変わらない状態にて電縫溶接が可能である。
On the other hand, if the coiling temperature is set to 600°C or higher, as shown in Figure 4 (the strength level of general ERW steel pipe is 40kg/
It becomes a hot-rolled wire material weighing from - to 60 kg/-, and is
It is possible to perform electric resistance welding in the same condition as for ll pipes.

さらに、造管性に悪影響を与える要因として、素材強度
のバラツキがある。インパクトビーム用素材は薄肉材料
が多く、熱延後の温度降下は比較的速い。その結果冷却
条件の微妙な違いにより巻取温度に影響を生じ易く、6
00℃未満の場合素材強度は巻取温度の変化に対応して
大きく変化し、その後の造管での成形の安定性、さらに
は電縫溶接の安定性に悪影響を及ぼす。第3図に示す如
く600℃以上では、巻取温度に対する素材強度のバラ
ツキ範囲は非常に少なく、600℃以上の巻取温度とす
ることにより良好な造管性が得られる。
Furthermore, a factor that adversely affects pipe formability is variation in material strength. Many materials for impact beams are thin-walled, and the temperature drop after hot rolling is relatively fast. As a result, slight differences in cooling conditions tend to affect the winding temperature.
When the temperature is less than 00°C, the strength of the material changes greatly in response to changes in the winding temperature, which adversely affects the stability of subsequent pipe forming and furthermore the stability of electric resistance welding. As shown in FIG. 3, at a temperature of 600° C. or higher, the range of variation in material strength with respect to the coiling temperature is very small, and by setting the coiling temperature to 600° C. or higher, good pipe formability can be obtained.

以上のような成分・熱延条件にて製造した熱延綱材は、
電kiliil管とするのが容易であり、電縫鋼管とし
たのち、焼入処理を実施することにより引張強さ120
kg/−以上で、延性・靭性に優れ、車体補強用電縫鋼
管として良好な性能を示す。
The hot-rolled steel material manufactured with the above ingredients and hot-rolling conditions is
It is easy to make an ERW pipe, and after making it into an ERW steel pipe, it can be hardened to have a tensile strength of 120.
kg/- or more, it has excellent ductility and toughness, and exhibits good performance as an electric resistance welded steel pipe for car body reinforcement.

ここで、電縫管とした後の焼入熱処理方法は、特に限定
しないが、例えば高周波焼入等がある。
Here, the quenching heat treatment method after forming the electric resistance welded tube is not particularly limited, but includes, for example, induction hardening.

(実施例) 第1表に本発明の実施例および比較例を示す。(Example) Table 1 shows examples and comparative examples of the present invention.

本発明の製造方法による熱延鋼板のJIS 5号引張り
特性及び当該熱延鋼板を外径31.8mmX肉厚2、0
 amの電縫鋼管とした後の熱処理方法、及び熱処理後
のJIS 11号引張り特性、シャルピー吸収エネルギ
ーを第1表に併せて示す。ここで、シャルピー吸収エネ
ルギーは、靭性評価用に専用に作製したフルサイズの試
験片にて得たデータを示す。
The JIS No. 5 tensile properties of the hot rolled steel sheet produced by the manufacturing method of the present invention and the hot rolled steel sheet having an outer diameter of 31.8 mm and a wall thickness of 2.0 mm.
Table 1 also shows the heat treatment method after making the am electric resistance welded steel pipe, the JIS No. 11 tensile properties after the heat treatment, and the Charpy absorbed energy. Here, Charpy absorbed energy indicates data obtained from a full-sized test piece prepared exclusively for toughness evaluation.

実施例A−Gではいずれの場合も熱延鋼材にて引張強度
60kgf/−程度以下で造管の際特に大きな問題を生
じなかった。電縫管とした後焼入処理を実施することに
よりいずれの場合も120kgf/−以上、伸び10%
程度、吸収エネルギー2kgfm/cm”程度以上が得
られ、しかも引張強度のバラツキは数kgf/−以下と
均一な組織の鋼管が得られた。
In all of Examples A to G, the hot-rolled steel had a tensile strength of about 60 kgf/- or less, and no major problems occurred during pipe production. By performing quenching treatment after making it into an electric resistance welded tube, in both cases, the weight is 120 kgf/- or more and the elongation is 10%.
A steel pipe with a uniform structure was obtained, in which an absorbed energy of 2 kgfm/cm or more was obtained, and the variation in tensile strength was less than a few kgf/cm.

比較例HはC含有量が本発明成分範囲より低い場合で、
電縫管とした後の熱処理によって、最終目標の強度が得
られない。
Comparative Example H is a case in which the C content is lower than the range of the components of the present invention,
The final target strength cannot be obtained due to heat treatment after making the ERW pipe.

比較例■はC量が本発明成分範囲より高い場合で、電縫
管の熱処理後、強度は充分達成できるもの、伸びが非常
に低い状態である。
Comparative Example (3) is a case where the amount of C is higher than the range of the components of the present invention, and after the heat treatment of the electric resistance welded tube, sufficient strength can be achieved, but elongation is very low.

比較例J−Nは600℃未満の低温巻取を実施した場合
であるが、最終的電縫管の特性としては比較的高強度・
高延性・高靭性は達成できるものの、その強度バラツキ
は20kgf/−近くあり、車体補強用鋼管として安定
した特性を確保し難い。
Comparative example J-N is a case where low-temperature winding was performed at less than 600°C, but the characteristics of the final ERW pipe are relatively high strength and
Although high ductility and high toughness can be achieved, the strength variation is close to 20 kgf/-, making it difficult to ensure stable properties as a steel pipe for reinforcing car bodies.

また、熱延鋼材段階にて高強度であり、造管性で劣る。In addition, it has high strength at the hot-rolled steel stage and is inferior in pipe formability.

比較例J、L、Mは通常ラインで電縫管とした際、せん
断工程の丸刃の欠損にて、せん新品質を良好に保つのが
難しく、電縫網管化する場合特殊な対策を要する。また
、比較例に、Nは素材の強度は若干低下され、せん断丸
刃の寿命の問題はあるものの、比較的良好なせん新品質
が得られた。ただし、鋼帯先後端部のハンドリングの困
難さ、電縫管成形の際の反力が高く、調整等の負荷が増
え、通常強度材より生産性の低下が顕著である。
Comparative examples J, L, and M are difficult to maintain good shearing quality due to the breakage of the round blade during the shearing process when they are made into electric resistance welded pipes on a normal line, and special measures are required when making them into electric resistance welded pipes. . In addition, in the comparative example, although the strength of the material of N was slightly lowered and there was a problem with the life of the shearing round blade, relatively good new shearing quality was obtained. However, it is difficult to handle the leading and trailing ends of the steel strip, the reaction force during the forming of the electric resistance welded tube is high, the load for adjustment, etc. increases, and the productivity decreases more markedly than with ordinary strength materials.

(発明の効果) 以上説明したように・本発明によれば、車体補強用型W
E管として有用な、伸び・靭性に優れた、引張強さ12
0kgf/−以上の高強度電縫鋼管用素材で、しかも電
縫網管とする際の作業負荷は従来の低強度材と何等変わ
らない熱延鋼材を得ることができる。
(Effect of the invention) As explained above, according to the present invention, the car body reinforcement mold W
Excellent elongation and toughness, useful as E-pipe, tensile strength 12
It is possible to obtain a hot-rolled steel material that is a material for high-strength electric resistance welded steel pipes with a strength of 0 kgf/- or more, and whose work load when forming an electric resistance welded mesh pipe is no different from that of conventional low-strength materials.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は、熱延綱材の炭素含有量が、焼入処理後の最終
的な電縫管の引張り特性に対する影響を示す図、第2図
は、熱延綱材の炭素含有量が、焼入処理後の最終的な電
縫管の引張り強さ、シャルピー衝撃値に対する影響を示
す図、第3図は焼入後の強度特性に対する巻取温度条件
の影響を示す図、第4図は、巻取温度の熱延鋼材の引張
り強さに対する効果を示す図である。 gl、5&、す5東之(kpl/n;評りイ申ひ 第2図 C合省量 (wtZ) \  \  \  \ (〜  −有 も  0  も  ) \  \ cll   へ C111も
Figure 1 shows the effect of the carbon content of the hot-rolled steel wire on the tensile properties of the final ERW tube after quenching. Figure 3 shows the effect of winding temperature conditions on the strength characteristics after quenching. FIG. 2 is a diagram showing the effect of coiling temperature on the tensile strength of hot rolled steel. gl, 5 &, Su5 Higashiyuki (kpl/n; evaluation is good, figure 2, C combined quantity (wtZ) \ \ \ \ \ (〜 -existent and 0) \ \ Cll to C111 too

Claims (2)

【特許請求の範囲】[Claims] (1)C:0.15〜0.25%(重量%、以下同じ)
Mn≦1.5% Si≦0.5% Ti≦0.04% B:0.0003〜0.0035% N≦0.0080% を含有し、残部Feおよび不可避的不純物よりなる鋼を
素材とし、熱間圧延後600℃以上で巻取ることを特徴
とする車体補強電縫鋼管用熱延鋼材の製造方法。
(1) C: 0.15-0.25% (weight%, same below)
Mn≦1.5% Si≦0.5% Ti≦0.04% B: 0.0003 to 0.0035% N≦0.0080%, the balance being Fe and unavoidable impurities. A method for producing a hot-rolled steel material for car body reinforcement ERW steel pipes, which comprises hot-rolling and then winding at 600°C or higher.
(2)C:0.15〜0.25%(重量%、以下同じ)
Mn≦1.5% Si≦0.5% Ti≦0.04% B:0.0003〜0.0035% N≦0.0080% を含有し、さらに Ni≦0.5% Cr≦0.5% Mo≦0.5% の一種または二種以上を含有し、残部Feおよび不可避
的不純物よりなる鋼を素材とし、熱間圧延後600℃以
上で巻取ることを特徴とする車体補強電縫鋼管用熱延鋼
材の製造方法。
(2) C: 0.15-0.25% (weight%, same below)
Contains Mn≦1.5% Si≦0.5% Ti≦0.04% B: 0.0003 to 0.0035% N≦0.0080%, and further includes Ni≦0.5% Cr≦0.5 %Mo≦0.5%, the balance being Fe and unavoidable impurities, and is characterized by being coiled at 600°C or higher after hot rolling. Method of manufacturing hot rolled steel for use.
JP2175113A 1990-07-02 1990-07-02 Manufacturing method of hot-rolled steel for body-reinforced ERW steel pipe manufactured by induction hardening Expired - Lifetime JPH0774382B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2175113A JPH0774382B2 (en) 1990-07-02 1990-07-02 Manufacturing method of hot-rolled steel for body-reinforced ERW steel pipe manufactured by induction hardening

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2175113A JPH0774382B2 (en) 1990-07-02 1990-07-02 Manufacturing method of hot-rolled steel for body-reinforced ERW steel pipe manufactured by induction hardening

Publications (2)

Publication Number Publication Date
JPH0463227A true JPH0463227A (en) 1992-02-28
JPH0774382B2 JPH0774382B2 (en) 1995-08-09

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1693476A1 (en) * 2003-12-12 2006-08-23 JFE Steel Corporation Steel product for structural member of automobile and method for production thereof
US8113735B2 (en) 2005-03-31 2012-02-14 Nhk Spring Co., Ltd. Joint structure and joining method
US10000111B2 (en) 2013-09-18 2018-06-19 Shiroki Corporation Garnish and frame molding apparatus and method of producing a vehicle door

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5325211A (en) * 1976-08-20 1978-03-08 Nippon Steel Corp Production of high tensile cold rolled steel sheet with excellent ductility by continuous annealing
JPS58104160A (en) * 1981-12-17 1983-06-21 Nisshin Steel Co Ltd Steel plate for precision blanking work with superior carburizing characteristic and hardenability and its manufacture
JPS6213533A (en) * 1985-07-09 1987-01-22 Nippon Steel Corp Manufacture of high strength steel sheet having superior bending characteristic
JPS6314817A (en) * 1986-07-05 1988-01-22 Nippon Steel Corp Production of high-strength thin steel sheet having excellent bending characteristic

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5325211A (en) * 1976-08-20 1978-03-08 Nippon Steel Corp Production of high tensile cold rolled steel sheet with excellent ductility by continuous annealing
JPS58104160A (en) * 1981-12-17 1983-06-21 Nisshin Steel Co Ltd Steel plate for precision blanking work with superior carburizing characteristic and hardenability and its manufacture
JPS6213533A (en) * 1985-07-09 1987-01-22 Nippon Steel Corp Manufacture of high strength steel sheet having superior bending characteristic
JPS6314817A (en) * 1986-07-05 1988-01-22 Nippon Steel Corp Production of high-strength thin steel sheet having excellent bending characteristic

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1693476A1 (en) * 2003-12-12 2006-08-23 JFE Steel Corporation Steel product for structural member of automobile and method for production thereof
EP1693476A4 (en) * 2003-12-12 2009-07-22 Jfe Steel Corp Steel product for structural member of automobile and method for production thereof
US8747578B2 (en) 2003-12-12 2014-06-10 Jfe Steel Corporation Steel for structural part of automobile and method for producing the same
US8113735B2 (en) 2005-03-31 2012-02-14 Nhk Spring Co., Ltd. Joint structure and joining method
US10000111B2 (en) 2013-09-18 2018-06-19 Shiroki Corporation Garnish and frame molding apparatus and method of producing a vehicle door

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