JPS61264160A - High-strength hot-rolled steel sheet of 60kgf/mm2 level for direct current butt welding - Google Patents

High-strength hot-rolled steel sheet of 60kgf/mm2 level for direct current butt welding

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Publication number
JPS61264160A
JPS61264160A JP10179085A JP10179085A JPS61264160A JP S61264160 A JPS61264160 A JP S61264160A JP 10179085 A JP10179085 A JP 10179085A JP 10179085 A JP10179085 A JP 10179085A JP S61264160 A JPS61264160 A JP S61264160A
Authority
JP
Japan
Prior art keywords
steel sheet
strength hot
rolled steel
steel
less
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP10179085A
Other languages
Japanese (ja)
Inventor
Ichiro Kokubo
小久保 一郎
Kazuhiko Gunda
郡田 和彦
Kazuhiro Mimura
和弘 三村
Zenichi Shibata
柴田 善一
Shunichi Hashimoto
俊一 橋本
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.)
Kobe Steel Ltd
Original Assignee
Kobe Steel Ltd
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 Kobe Steel Ltd filed Critical Kobe Steel Ltd
Priority to JP10179085A priority Critical patent/JPS61264160A/en
Publication of JPS61264160A publication Critical patent/JPS61264160A/en
Priority to US07/087,967 priority patent/US4880480A/en
Pending legal-status Critical Current

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Abstract

PURPOSE:To provide a high-strength hot-rolled steel sheet having improved DC butt weldability and formability by adding proper amounts of Nb and Ti to a steel contg. specified amounts of C, Si, Mn, Al, P and S and by specifying the carbon equiv. CONSTITUTION:The composition of a high-strength hot-rolled steel sheet of 60kgf/mm<2> level is composed of, by weight, 0.04-0.10% C, <=0.3% Si, 1.0-1.6% Mn, 0.01-0.05% Al, <=0.03% P, <=0.01% S, <=0.08% in total of 0.02-0.06% Nb and/or 0.03-0.08% Ti and the balance essentially Fe, and the carbon, equiv. Ceq represented by a formula Ceq=C+Si/24+Mn/6 is regulated to 0.28-0.34. By the composition, the maximum hardness Hv of the weld zone of the steel sheet can be restricted to <=about 300, superior total elongation is ensured, and when the steel sheet is formed into wheel rims, etc., rejects are produced at a lowered rate.

Description

【発明の詳細な説明】 (産業上の利用分野) 本発明は、60kgf/mm2級直流バット溶接用高強
度熱延鋼板に関し、詳しくは、自動車用ホイールリムの
製造に適する直流バット溶接性及び成形性にすぐれた6
 0 kg4/mmz級直流バット溶接用高強度熱延m
板に関する。
Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a 60 kgf/mm class 2 high-strength hot rolled steel plate for direct current butt welding. Excellent sex 6
0 kg4/mmz class high strength hot rolled m for DC butt welding
Regarding the board.

(従来の技術) 自動車重量を軽減して燃料費を節減するために、車体を
小型化すると共に、高強度鋼材の採用による材料変更が
種々試みられている。特に、車輪の軽量化は燃料費の節
減に効果的であるとされ、ホイールリムに対する高強度
熱延鋼板の適用が鋭意研究されている。
(Prior Art) In order to reduce the weight of automobiles and reduce fuel costs, various attempts have been made to reduce the size of automobile bodies and to change materials by using high-strength steel materials. In particular, reducing the weight of wheels is said to be effective in reducing fuel costs, and the application of high-strength hot-rolled steel sheets to wheel rims is being intensively studied.

ホイールリムは、従来、所定の幅及び長さに切断された
鋼板をリング状に成形し、端部を溶接した後、数工程の
ロールフォージングを経て製造されている。上記溶接に
は、従来、フラッシュバット溶接が採用されているが、
近年、フラッシュが飛ばないので、粉塵による作業環境
の劣化がないこと、騒音が生じないこと、更に、フラッ
シュで消耗する部分がないので、1%程度の歩留りの向
上を図り得ること等の理由から、直流バット溶接が好ん
で採用される傾向にある。
Wheel rims have conventionally been manufactured by forming a steel plate cut into a predetermined width and length into a ring shape, welding the ends, and then performing several roll forging steps. Conventionally, flash butt welding is used for the above welding, but
In recent years, because the flash does not fly off, there is no deterioration of the working environment due to dust, no noise is generated, and since there are no parts that are consumed by the flash, it is possible to improve the yield by about 1%. , DC butt welding tends to be preferred.

しかし、この直流バット溶接を採用するホイールリムの
新しい製造方法において、新しい問題が生じている。即
ち、従来、引張強さが45kgf/mi”以下の鋼板を
用いるときには殆ど問題とされなかったが、CやMn量
が多い高強度鋼板を用いるとき、大電流による溶接、又
はアップセット過程中或いはアップセット後に苔いても
通電するという溶接条件のために、溶接終了時点でオー
ステナイト粒が粗大化し、従って、冷却過程で焼入れ性
が高くなっているために、マルテンサイト又は硬質のベ
イナイトに変態しやすくなり、溶接部の硬度が非常に高
くなって、その結果、加工途中で溶接接合面から割れが
発生しやすい。この溶接部の硬゛度の最高値の限界は、
従来、何ら明確ではないが、本発明者らの研究によれば
、上限をHV300程度とすることが好ましいところ、
従来の高張力鋼によれば、直流バット溶接材の溶接部の
最高硬度は多くの場合、Hv300を越え、フラッシュ
バット溶接材に比べて100以上も高く、また、組織的
にもマルテンサイトに近い。
However, new problems have arisen in this new method of manufacturing wheel rims that employs DC butt welding. That is, in the past, when using steel plates with a tensile strength of 45 kgf/mi or less, there was almost no problem, but when using high-strength steel plates with a large amount of C or Mn, welding with a large current, during the upset process, or Due to the welding conditions that conduct electricity even if there is moss after the upset, the austenite grains become coarse at the end of welding, and as a result, the hardenability becomes high during the cooling process, making it easy to transform into martensite or hard bainite. As a result, the hardness of the welded part becomes extremely high, and as a result, cracks are likely to occur from the welded joint surface during processing.The maximum hardness of this welded part is
Although it is not clear in the past, according to the research of the present inventors, it is preferable to set the upper limit to about HV300;
According to conventional high-strength steel, the maximum hardness of the welded part of DC butt welded materials often exceeds Hv300, which is more than 100 Hv higher than that of flash butt welded materials, and the structure is close to martensite. .

(発明の目的) このように、溶接部の硬度が高くなる原因は、直流バッ
ト溶接によれば、フラッシュバット溶接に比べて、大電
流を流して溶接する点にあるが、本発明者らは鋼材面か
らこの問題を解決するために鋭意研究した結果、炭素当
量(Ceq) 、即ち、を0.34%以下に抑え、且つ
、所定量のNb及び/又はTiを添加することにより、
溶接部の最高硬度をHv 3 Q O以下に抑制し得る
と共に、すぐれた全伸びを確保して、ホイールリム成形
における不良率を顕著に減少させ得ることを見出ルで、
本発明に至ったものである。
(Object of the Invention) According to DC butt welding, the reason why the hardness of the welded part increases is that a larger current is passed through welding than in flash butt welding. As a result of intensive research to solve this problem from the perspective of steel materials, we found that by suppressing the carbon equivalent (Ceq) to 0.34% or less and adding a predetermined amount of Nb and/or Ti,
We have discovered that it is possible to suppress the maximum hardness of the welded part to below Hv 3 Q O, ensure excellent total elongation, and significantly reduce the defective rate in wheel rim molding,
This led to the present invention.

従って、本発明は、例えば、自動車用ホイールリムの製
造に適する直流バラ目容接性及び成形性にすぐれる6 
0 kgf/mm”級直流バット溶接用高強度熱延鋼板
を提供することを目的とする。
Therefore, the present invention provides, for example, a 660-600 600-6006 having excellent direct current acceptability and formability suitable for manufacturing wheel rims for automobiles.
The purpose of the present invention is to provide a high-strength hot-rolled steel sheet for direct current butt welding of the 0 kgf/mm" class.

(発明の構成) 本発明による6 0kgf/mm2級直流バット溶接高
強度熱延鋼板は、重量%で (a)C   0.04〜0.10%、Si0.3%以
下、 Mn  1.0〜1.6%、 AI 0.01〜0.05%、 P   0.03%以下及び S   0.01%以下を含有すると共に、(b)Nb
  0.02〜0.06%及びTi0.03〜0.08
% よりなる群から選ばれる1種又は2種の元素を総量にて
0.08%以下の範囲で含有し、且つ、炭素当量 が0.28〜0.34%であることを特徴とする。
(Structure of the Invention) The 60 kgf/mm2 class DC butt welded high-strength hot rolled steel sheet according to the present invention has (a) C 0.04 to 0.10%, Si 0.3% or less, Mn 1.0 to (b) Nb
0.02-0.06% and Ti0.03-0.08
% in a total amount of 0.08% or less, and has a carbon equivalent of 0.28 to 0.34%.

先ず、本発明鋼における化学成分の限定理由について説
明する。
First, the reasons for limiting the chemical components in the steel of the present invention will be explained.

Cは、鋼に所要の強度を与えるために必要な元素であっ
て、少なくとも0.05%の添加が必要である。一方、
直流バット溶接は、前記したように、溶接部の硬度を高
める特性を有しているから、Cを過多に添加することは
好ましくなく、本発明鋼においては、C添加量の上限を
0.10%とする。
C is an element necessary to give the steel the required strength, and must be added in an amount of at least 0.05%. on the other hand,
As mentioned above, DC butt welding has the property of increasing the hardness of the welded part, so it is not preferable to add too much C. In the steel of the present invention, the upper limit of the amount of C added is set to 0.10. %.

フラッシュバット溶接の場合には、溶接過程において生
成する酸化物であるベネトレーターの生成を抑制するた
めに、Stが添加される。しかし、直流バット溶接の場
合は、溶接機構上、ペネトレーターが生成し難いので、
添加量を0.3%以下に規制すれば、ペネトレーターの
生成を抑制するためには十分である。0.3%以上を越
えて多量に添加するときは、却って母材の電気抵抗値を
高めて、溶接のばらつきが生じやすくなるので、好まし
くない。
In the case of flash butt welding, St is added to suppress the formation of venetrator, which is an oxide generated during the welding process. However, in the case of DC butt welding, it is difficult to generate penetrators due to the welding mechanism.
If the amount added is regulated to 0.3% or less, it is sufficient to suppress the formation of penetrators. When added in a large amount exceeding 0.3%, it is not preferable because it increases the electrical resistance value of the base metal and tends to cause welding variations.

Mnは、鋼の強度を高めるために必要であり、60 k
gf/mm”以上の引張強さを持つ高強度鋼板を得るた
めには、1.0%以上の添加が必要である。
Mn is necessary to increase the strength of steel, and at 60 k
In order to obtain a high-strength steel plate with a tensile strength of 1.0% or more, it is necessary to add 1.0% or more.

しかし、過多に添加するときは、溶接部の硬度が高くな
り、割れの原因となると共に、第2層が層状に並びやす
く、延性をも劣化させることから、添加量の上限は1.
6%とする。
However, when adding too much, the hardness of the weld increases, causing cracks, and the second layer tends to form in layers, which also deteriorates ductility, so the upper limit of the amount added is 1.
6%.

Pは、これを鋼中に過剰に含有させるときは、溶接部を
劣化させるので、0.03%以下の含有量に規制する。
When excessive P is contained in steel, it deteriorates the welded part, so the content is regulated to 0.03% or less.

Sは、伸長したMnSの量を増加させ、メタルフローに
沿った割れの原因となるので、その含有量はできる限り
低い方がよいが、実質的には0.01%以下に規制すれ
ば十分である。
S increases the amount of elongated MnS and causes cracks along the metal flow, so it is better to keep its content as low as possible, but in practice it is sufficient to limit it to 0.01% or less. It is.

A2は、鋼の脱酸のために0.01%以上の添加が必要
である。しかし、過多に添加するときは、アルミナ系介
在物を増加させ、MnSと同様にフック状割れの原因と
なるので、添加量の上限を0.05%とする。
A2 needs to be added in an amount of 0.01% or more to deoxidize the steel. However, when added in excess, it increases alumina-based inclusions and causes hook-like cracks like MnS, so the upper limit of the amount added is set at 0.05%.

本発明鋼には、上記した元素に加えて、Nb0.02〜
0.06%及び Ti0.03〜0.08% よりなる群から選ばれる1種又は2種の元素を総量にて
0.08%以下の範囲で添加することができる。
In addition to the above-mentioned elements, the steel of the present invention contains Nb0.02~
One or two elements selected from the group consisting of 0.06% and 0.03 to 0.08% Ti can be added in a total amount of 0.08% or less.

Nb及びTiは、析出強化によって鋼強度を高める元素
であり、この効果を有効に発現させるためには、Nbに
ついては少なくとも0.02%を、また、Tiについて
は少なくとも0.03%を添加することが必要である。
Nb and Ti are elements that increase steel strength through precipitation strengthening, and in order to effectively express this effect, at least 0.02% of Nb and at least 0.03% of Ti are added. It is necessary.

この強化効果は、それぞれの元素について添加量に比例
するが、過多に添加することは、他方で母材の延性劣化
を招くと共に、製造費用の上昇を招くので、添加量の上
限は、Nbについては0.06%、Tiについては0.
08%とする。これら元素は、複合添加してもよいが、
しかし、NbとTiの添加量が総量にして0.08%を
越えるときは、単独にて過多に添加する場合と同様に、
母材を劣化させるので、添加量は総量にて0.08%以
下とする。
This strengthening effect is proportional to the amount of each element added, but adding too much will lead to deterioration of the ductility of the base material and increase manufacturing costs, so the upper limit of the amount added is set for Nb. is 0.06%, and Ti is 0.06%.
08%. These elements may be added in combination, but
However, when the total amount of Nb and Ti added exceeds 0.08%, the
Since it deteriorates the base material, the total amount added should be 0.08% or less.

更に、本発明鋼においては、上記したNb及びTiより
なる群から選ばれる少なくとも1゛種の元素と共に、又
はそれらとは別に、Ca及びREMよりなる群から選ば
れる少なくとも1種の元素を添加することができる。こ
れら元素は、伸長したMnSを球状化させて、フック状
割れの発生を防止するうえに効果的である。このような
効果を有効に得るには、Caについては0.OOO5%
、REMについては0.OO5%以上の添加を必要とす
る。しかし、過多に添加しても、効果が飽和するのみな
らず、溶接部にペネトレーターを生成し、これを起点と
する割れが発生しやすくなるので、添加量の上限は、C
aについては0.01%、REMについては0.1%と
する。
Furthermore, in the steel of the present invention, at least one element selected from the group consisting of Ca and REM is added together with or separately from at least one element selected from the group consisting of Nb and Ti. be able to. These elements are effective in making the elongated MnS spheroidal and preventing the occurrence of hook-like cracks. In order to effectively obtain such an effect, Ca should be set at 0. OOO5%
, 0 for REM. It is necessary to add 5% or more of OO. However, adding too much C not only saturates the effect, but also creates penetrators in the weld, making cracks more likely to start from these.
It is assumed that a is 0.01% and REM is 0.1%.

次に、本発明鋼は、上記した化学成分を有すると共に、
前記したように、Ceqが0.28〜0.34%の範囲
にあることを要する。本発明者らは、直流バット溶接を
行ない、ホイールリムを製作するに際して、鋼のCeq
と溶接部最高硬度とは密接な関係を有することを見出し
た。即ち、第2図にCeqと溶接部最高硬度との関係を
示すように、先ず、Ceqが0.34%を越えるときは
、溶接部最高硬度がHV300を越える。次に、リム成
形時の不良率は、溶接部最高硬度を下げれば下げるほど
減少するが、60 kgf/mm2級鋼に限定す扱網、
Ceqを低減するにつれて、強度確保のために、N、b
やTiの大量添加、又は極低温巻取によるマルテンサイ
トの導入等が必要となる。しかし、一方において、Nb
やTiの大量添加は全伸びを不足させ、また、マルテン
サイトの導入は、熱影響部において母材より硬度の低下
をきたすために、熱影響で板厚減少が生じ、いずれにし
ても、再び不良率を増大させ、又は製造費用を著しく上
昇させることとなる。従って、本発明鋼においては、C
eqを0.28%以上とし、Nb及びTiをそれぞれ0
.06%以下及び0.08%以下として、全伸び23%
以上を確保するのである。
Next, the steel of the present invention has the above chemical components, and
As mentioned above, Ceq is required to be in the range of 0.28 to 0.34%. The present inventors performed direct current butt welding to manufacture wheel rims using Ceq steel.
It was found that there is a close relationship between the hardness of the weld and the maximum hardness of the weld. That is, as shown in FIG. 2, which shows the relationship between Ceq and the maximum hardness of the weld, when Ceq exceeds 0.34%, the maximum hardness of the weld exceeds HV300. Next, the defect rate during rim forming will decrease as the maximum hardness of the welded part is lowered, but if the handling network is limited to 60 kgf/mm2 grade steel,
As Ceq is reduced, N, b is added to ensure strength.
It is necessary to add a large amount of Ti, or introduce martensite by cryogenic winding. However, on the other hand, Nb
Addition of a large amount of Ti or Ti will result in insufficient total elongation, and the introduction of martensite will cause a decrease in hardness in the heat-affected zone compared to the base material, resulting in a decrease in plate thickness due to heat influence, and in any case, This will increase the defective rate or significantly increase manufacturing costs. Therefore, in the steel of the present invention, C
eq is 0.28% or more, and Nb and Ti are each 0.
.. 0.06% or less and 0.08% or less, total elongation 23%
The above is to be ensured.

このように、本発明鋼によれば、Ceqを0.28〜0
.34%の範囲に限定して、フェライト・ベイナイト、
フェライト・ベイナイト・パーライト又はフェライト・
パーライト組織によって、全伸び23%以上を確保する
ことができる。
Thus, according to the steel of the present invention, Ceq is 0.28 to 0.
.. Ferrite bainite limited to a range of 34%,
Ferrite, bainite, pearlite or ferrite
Due to the pearlite structure, a total elongation of 23% or more can be ensured.

(発明の効果) 以上のように、本発明鋼は、60kgf/n+m2級高
張力鋼を基本鋼とし、Nb及び/又はTiをそれぞれ0
.06%及び0.08%以下、且つ、総量にて0.08
%以下の範囲にて所定量を添加すると共に、Ceqを0
.28〜0.34%の範囲に規制することによって、溶
接部の硬度がHV300以下、母材の全伸びが23%以
上である6 0kgf/mm”級直流バット溶接用高強
度熱延鋼板を得ることができる。
(Effects of the Invention) As described above, the steel of the present invention uses 60 kgf/n+m2 class high tensile strength steel as the basic steel, and contains 0 each of Nb and/or Ti.
.. 0.06% and 0.08% or less, and the total amount is 0.08
% or less, and add Ceq to 0.
.. By regulating the content within the range of 28 to 0.34%, a 60 kgf/mm" class high-strength hot rolled steel plate for direct current butt welding, in which the hardness of the welded part is HV300 or less and the total elongation of the base material is 23% or more, can be obtained. be able to.

実施例1 第1表に示す化学成分を有する鋼を溶製し、連続鋳造法
又は造塊法にて厚さ220 mlのスラブを製造した。
Example 1 Steel having the chemical composition shown in Table 1 was melted and a slab with a thickness of 220 ml was manufactured by continuous casting or ingot forming.

この後、通常の圧延方法にて厚さ2.6鶴の鋼板とし、
400〜650℃の間の温度で巻取った。スキンパス及
び酸洗を経てスリットコイル化し、第1図に示す溶接条
件にて直流バット溶接し、引き続いてリム成形を行なっ
た。
After this, it is made into a steel plate with a thickness of 2.6 mm using the normal rolling method,
It was wound up at a temperature between 400 and 650°C. After skin pass and pickling, it was formed into a slit coil, then DC butt welded under the welding conditions shown in FIG. 1, and subsequently rim-formed.

得られた熱延鋼板の機械的性質及びリム成形不良率を表
に示す。また、鋼のCeqと溶接部最高硬度との関係を
第2図に示す。尚、付記した数字は、表中の鋼番号を示
す(第3図においても同じ)。
The mechanical properties and rim forming defect rate of the obtained hot rolled steel sheet are shown in the table. Moreover, the relationship between Ceq of steel and the maximum hardness of the welded part is shown in FIG. Note that the appended numbers indicate the steel numbers in the table (the same applies to FIG. 3).

Ceqの増加と共に溶接部最高硬度は高くなり、0゜3
4%を越えると、硬度はHv300を越える。
As Ceq increases, the maximum hardness of the weld increases and reaches 0°3.
When it exceeds 4%, the hardness exceeds Hv300.

第3図にCeqとリム成形不良率との関係を示す。FIG. 3 shows the relationship between Ceq and rim molding defect rate.

Ceqが0.28〜0.34%の範囲にあるときは、リ
ム成形不良率は3%以下に抑えられているが、0゜34
%を越えるとき、不良率が急激に増大する。
When Ceq is in the range of 0.28 to 0.34%, the rim molding defect rate is suppressed to 3% or less, but 0°34
%, the defective rate increases rapidly.

この不良は、主としてリム成形の第1工程であるフレア
一工程で生じる溶接接合部からの割れであって、溶接部
硬度が過度に高(なったことによる。
This defect is mainly caused by cracking at the welded joint that occurs during the flaring step, which is the first step of rim forming, and is caused by the hardness of the welded portion being excessively high.

一方、Ceqが0.28%よりも小さいときも、不良率
が増大する。この不良は、主として、溶接熱影響部又は
強加工部での肉減りであって、全伸びの不足による。
On the other hand, when Ceq is smaller than 0.28%, the defect rate also increases. This defect is mainly due to thinning in the weld heat-affected zone or heavily processed zone, and is due to lack of total elongation.

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

第1図は、実施例における直流バット溶接の条件を示す
グラフ、第2図は、Ceqと直流バット溶接による溶接
部最高硬度の関係を示すグラフ、第3図は、Ceqとリ
ム成形不良率との関係を示すグラフである。 第3図 Ce((〆)
Fig. 1 is a graph showing the conditions of DC butt welding in the example, Fig. 2 is a graph showing the relationship between Ceq and the maximum hardness of the welded part by DC butt welding, and Fig. 3 is a graph showing the relationship between Ceq and rim forming defect rate. It is a graph showing the relationship. Figure 3 Ce ((〆)

Claims (2)

【特許請求の範囲】[Claims] (1)重量%で (a)C0.04〜0.10%、 Si0.3%以下、 Mn1.0〜1.6%、 Al0.01〜0.05%、 P0.03%以下及び S0.01%以下を含有すると共に、 (b)Nb0.02〜0.06%及び Ti0.03〜0.08% よりなる群から選ばれる1種又は2種の元素を総量にて
0.08%以下の範囲で含有し、且つ、炭素当量 Ceq=C+(Si/24)+(Mn/6)が0.28
〜0.34%であることを特徴とする60kgf/mm
^2級直流バット溶接高強度熱延鋼板。
(1) In weight% (a) C0.04-0.10%, Si0.3% or less, Mn1.0-1.6%, Al0.01-0.05%, P0.03% or less, and S0. (b) 0.08% or less in total of one or two elements selected from the group consisting of Nb 0.02-0.06% and Ti 0.03-0.08%. and the carbon equivalent Ceq=C+(Si/24)+(Mn/6) is 0.28
~0.34% 60kgf/mm
^2nd class DC butt welded high strength hot rolled steel plate.
(2)重量%で (a)C0.04〜0.10%、 Si0.3%以下、 Mn1.0〜1.6%、 Al0.01〜0.05%、 P0.03%以下及び S0.01%以下と、 (b)Nb0.02〜0.06%及び Ti0.03〜0.08% よりなる群から選ばれる1種又は2種の元素を総量にて
0.08%以下の範囲で含有すると共に、 (c)Ca0.0005〜0.01%及び REM0.005〜0.1% よりなる群から選ばれる少なくとも1種の元素を含有し
、且つ、炭素当量 Ceq=C+(Si/24)+(Mn/6)が0.28
〜0.34%であることを特徴とする60kgf/mm
^2級直流バット溶接高強度熱延鋼板。
(2) In weight% (a) C0.04-0.10%, Si0.3% or less, Mn1.0-1.6%, Al0.01-0.05%, P0.03% or less, and S0. (b) one or two elements selected from the group consisting of Nb 0.02-0.06% and Ti 0.03-0.08% in a total amount of 0.08% or less; (c) contains at least one element selected from the group consisting of Ca0.0005-0.01% and REM0.005-0.1%, and carbon equivalent Ceq=C+(Si/24 )+(Mn/6) is 0.28
~0.34% 60kgf/mm
^2nd class DC butt welded high strength hot rolled steel plate.
JP10179085A 1985-01-24 1985-05-13 High-strength hot-rolled steel sheet of 60kgf/mm2 level for direct current butt welding Pending JPS61264160A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP10179085A JPS61264160A (en) 1985-05-13 1985-05-13 High-strength hot-rolled steel sheet of 60kgf/mm2 level for direct current butt welding
US07/087,967 US4880480A (en) 1985-01-24 1987-08-17 High strength hot rolled steel sheet for wheel rims

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10179085A JPS61264160A (en) 1985-05-13 1985-05-13 High-strength hot-rolled steel sheet of 60kgf/mm2 level for direct current butt welding

Publications (1)

Publication Number Publication Date
JPS61264160A true JPS61264160A (en) 1986-11-22

Family

ID=14309960

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10179085A Pending JPS61264160A (en) 1985-01-24 1985-05-13 High-strength hot-rolled steel sheet of 60kgf/mm2 level for direct current butt welding

Country Status (1)

Country Link
JP (1) JPS61264160A (en)

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4849614A (en) * 1971-10-26 1973-07-13
JPS4879722A (en) * 1972-01-31 1973-10-25
JPS4881721A (en) * 1972-02-04 1973-11-01
JPS4986213A (en) * 1972-12-23 1974-08-19
JPS5247512A (en) * 1975-10-14 1977-04-15 Nippon Kokan Kk <Nkk> Production process of high tensile cold rolled steel sheet having litt le surface anisotropy
JPS535017A (en) * 1976-07-06 1978-01-18 Nippon Steel Corp High tensile cold rolled steel sheet and its production method
JPS53100118A (en) * 1977-02-15 1978-09-01 Kawasaki Steel Co Continously cast killed steel heat rolled belt having 40 to 60kg tensile strength for use as high frequency t type fittings
JPS5443822A (en) * 1977-09-14 1979-04-06 Nippon Steel Corp Manufacture of high tensile hot rolled steel sheet with low intrafacial plastic anisotropy
JPS5454915A (en) * 1977-10-11 1979-05-01 Nippon Steel Corp Production of high-tensile steel plate having good cold toughness and weldability
JPS54115619A (en) * 1978-02-28 1979-09-08 Kobe Steel Ltd Steel for welded structure with superior toughness and weld crack resistance in weld heat-affected zone
JPS5681620A (en) * 1979-12-05 1981-07-03 Nippon Steel Corp Production of tin base low yield ratio composite structure high tensile steel plate
JPS56146826A (en) * 1980-04-15 1981-11-14 Nippon Kokan Kk <Nkk> Production of high tensile steel sheet having low yield ratio and high ductility

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4849614A (en) * 1971-10-26 1973-07-13
JPS4879722A (en) * 1972-01-31 1973-10-25
JPS4881721A (en) * 1972-02-04 1973-11-01
JPS4986213A (en) * 1972-12-23 1974-08-19
JPS5247512A (en) * 1975-10-14 1977-04-15 Nippon Kokan Kk <Nkk> Production process of high tensile cold rolled steel sheet having litt le surface anisotropy
JPS535017A (en) * 1976-07-06 1978-01-18 Nippon Steel Corp High tensile cold rolled steel sheet and its production method
JPS53100118A (en) * 1977-02-15 1978-09-01 Kawasaki Steel Co Continously cast killed steel heat rolled belt having 40 to 60kg tensile strength for use as high frequency t type fittings
JPS5443822A (en) * 1977-09-14 1979-04-06 Nippon Steel Corp Manufacture of high tensile hot rolled steel sheet with low intrafacial plastic anisotropy
JPS5454915A (en) * 1977-10-11 1979-05-01 Nippon Steel Corp Production of high-tensile steel plate having good cold toughness and weldability
JPS54115619A (en) * 1978-02-28 1979-09-08 Kobe Steel Ltd Steel for welded structure with superior toughness and weld crack resistance in weld heat-affected zone
JPS5681620A (en) * 1979-12-05 1981-07-03 Nippon Steel Corp Production of tin base low yield ratio composite structure high tensile steel plate
JPS56146826A (en) * 1980-04-15 1981-11-14 Nippon Kokan Kk <Nkk> Production of high tensile steel sheet having low yield ratio and high ductility

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