JPH0774413B2 - Electric resistance welded steel pipe for machine structure with excellent machinability - Google Patents
Electric resistance welded steel pipe for machine structure with excellent machinabilityInfo
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- JPH0774413B2 JPH0774413B2 JP2020177A JP2017790A JPH0774413B2 JP H0774413 B2 JPH0774413 B2 JP H0774413B2 JP 2020177 A JP2020177 A JP 2020177A JP 2017790 A JP2017790 A JP 2017790A JP H0774413 B2 JPH0774413 B2 JP H0774413B2
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Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、被削性の優れた機械構造用電気抵抗溶接鋼管
に関するものである。TECHNICAL FIELD The present invention relates to an electric resistance welded steel pipe for machine structure having excellent machinability.
（従来の技術） 切削加工技術の進展、自動車その他の機械生産量の増大
に伴い、被削性の優れた鋼材の必要性が大きくなってい
る。機械構造用鋼管についても、切削加工の自動化、高
能率化によって切屑処理性、切屑仕上面の良好な材料が
望まれている。(Prior Art) With the progress of cutting technology and the increase in production of automobiles and other machines, the need for steel materials with excellent machinability is increasing. Also for steel pipes for machine structures, a material having good chip disposability and chip surface finish is desired by automating cutting and increasing efficiency.
一般の機械構造用鋼については、被削性を改善させるた
めに、例えば、特開昭55−85658号公報、特開昭57−140
853号公報や特開昭62−33747号公報に示されているよう
なＳ系快削鋼、Pb快削鋼、Ca快削鋼及びこれらの複合快
削鋼が開発され、実用化されている。しかしながら、被
削性の良好な機械構造用鋼管を電気抵抗溶接によって製
造しようとする際、これらの快削鋼の快削性元素が生成
する介在物は電気抵抗溶接性を劣化させ、溶接割れ、超
音波探傷試験時のUST不良、などによる大幅な歩留低下
の原因となるため、電気抵抗溶接管の材料としては使用
することができない。なお、これらの介在物による機械
的性質の劣化を防ぐために、特公昭61−16337号公報に
示すようにsol.Alを制限し、S,Ca,Oの量を特定している
ものもあるが、電気抵抗溶接の素材として用いる場合に
は、上記問題点を完全に解消するものではなく、さら
に、Siキルド鋼においてＯの量を0.0040重量％以下に低
減させることは、通常困難である。Regarding general machine structural steel, in order to improve machinability, for example, JP-A-55-85658 and JP-A-57-140 are used.
The S-based free-cutting steel, Pb free-cutting steel, Ca free-cutting steel, and their composite free-cutting steels as shown in Japanese Patent No. 853 and Japanese Patent Laid-Open No. 62-33747 have been developed and put into practical use. . However, when attempting to manufacture a steel pipe for machine structure having good machinability by electric resistance welding, inclusions generated by the free-cutting elements of these free-cutting steels deteriorate the electric resistance weldability and cause weld cracking, It cannot be used as a material for electric resistance welded pipes, as it causes a large decrease in yield due to UST failure during ultrasonic flaw detection tests. Incidentally, in order to prevent deterioration of mechanical properties due to these inclusions, as shown in Japanese Patent Publication No. 61-16337, sol.Al is limited, and the amount of S, Ca, O is specified. When used as a material for electric resistance welding, it does not completely eliminate the above problems, and it is usually difficult to reduce the amount of O to 0.0040% by weight or less in Si-killed steel.
（発明が解決しようとする課題） 本発明は、被削性の優れた機械構造用電縫鋼管を製造す
るにあたって、従来の快削鋼では、快削性元素が生成す
る介在物は、電気抵抗溶接性を著しく劣化させ、溶接割
れ、UST不良などの原因となるため、電気抵抗溶接管の
材料としては使用することができないという問題点を解
消し、機械構造用電縫鋼管の被削性改善要求に応えるこ
とを目的としてなされたものである。(Problems to be Solved by the Invention) In the present invention, in producing an electric resistance welded steel pipe for machine structure having excellent machinability, in the conventional free-cutting steel, inclusions generated by the free-cutting element have an electrical resistance. Weldability is remarkably deteriorated, which causes weld cracks, UST defects, etc., which eliminates the problem that it cannot be used as a material for electric resistance welded pipes, and improves the machinability of ERW steel pipes for machine structures. It was designed to meet the demand.
（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 the Problems) The gist of the present invention is as follows.
（１）重量％表示でC:0.02〜0.60％、Si:0.4％以下、M
n:0.20〜2.0％、P:0.030％以下、Si:0.040％以下、sol.
Al:0.001〜0.005％、N:0.0060％超0.0100％以下、O:0.0
060％以下、Ca:0.002〜0.020％でかつCa％／（1.25×Ｏ
％＋0.625×Ｓ％）≧0.05、を含有し、残部鉄および不
可避的不純物からなることを特徴とする被削性の優れた
機械構造用電気抵抗溶接鋼管。(1) C: 0.02 to 0.60% by weight%, Si: 0.4% or less, M
n: 0.20-2.0%, P: 0.030% or less, Si: 0.040% or less, sol.
Al: 0.001-0.005%, N: more than 0.0060% and 0.0100% or less, O: 0.0
060% or less, Ca: 0.002-0.020% and Ca% / (1.25 × O
% + 0.625 × S%) ≧ 0.05, and the balance is composed of iron and unavoidable impurities, and an electric resistance welded steel pipe for machine structure with excellent machinability.
（２）重量％表示でC:0.02〜0.60％、Si:0.4％以下、M
n:0.20〜2.0％、P:0.030％以下、S:0.040％以下、Cr:0.
10〜1.50％、Mo:0.10〜0.60％、sol.Al:0.001〜0.005
％、N:0.0060％超0.0100％以下、O:0.0060％以下、Ca:
0.002〜0.020％でかつCa％／（1.25×Ｏ％＋0.625×Ｓ
％）≧0.05、を含有し、残部鉄および不可避的不純物か
らなることを特徴とする被削性の優れた機械構造用電気
抵抗溶接鋼管。(2) C: 0.02-0.60%, Si: 0.4% or less, M in weight%
n: 0.20-2.0%, P: 0.030% or less, S: 0.040% or less, Cr: 0.
10-1.50%, Mo: 0.10-0.60%, sol.Al:0.001-0.005
%, N: more than 0.0060% and 0.0100% or less, O: 0.0060% or less, Ca:
0.002 to 0.020% and Ca% / (1.25 x O% + 0.625 x S
%) ≧ 0.05, and the balance is composed of iron and unavoidable impurities, and an electric resistance welded steel pipe for machine structure having excellent machinability.
ここで、本発明は、切屑処理性の良好な電気抵抗溶接管
を、歩留良く製造することを可能とするために、素材の
N,S,Ca,Oの量を特定したことを特徴としている。Here, in order to enable the production of an electric resistance welded pipe having good chip disposability with a good yield, the present invention is
It is characterized by specifying the amounts of N, S, Ca, and O.
（作用） 以下に、本発明の詳細を述べるとともに、前記のように
本発明の鋼の成分範囲を定めた理由について説明する。(Operation) The details of the present invention will be described below, and the reason for defining the component range of the steel of the present invention as described above will be described.
本発明は、切屑処理性の良好な機械構造用鋼管を、電気
抵抗溶接により製造することを目的としたもので、N,S,
Ca,Oの量を特定することにより、快削成分の介在物によ
る電気抵抗溶接の際の溶接割れ、UST不良などを原因と
する歩留の大幅低下を抑制している。The present invention is a steel pipe for machine structural good chip disposability, for the purpose of producing by electrical resistance welding, N, S,
By specifying the amounts of Ca and O, it is possible to suppress a significant decrease in yield due to weld cracks and UST defects during electric resistance welding due to inclusions of free-cutting components.
Ｃは、機械的強度を確保するために必須であるため、下
限を0.02％とした。また、0.60％を超えると靭性および
被削性が劣化する上、製管のための電気抵抗溶接時に、
その熱影響によって著しく硬化し加工性を損なうので、
その上限を0.60％とした。C is essential to secure mechanical strength, so the lower limit was made 0.02%. Further, if it exceeds 0.60%, the toughness and machinability deteriorate, and at the time of electric resistance welding for pipe manufacturing,
Due to the heat effect, it hardens significantly and the workability is impaired.
The upper limit was set to 0.60%.
Siは、脱酸上鋼に含まれる元素であるが、過剰に添加す
ると延性を低下させるほか、Siスケールの生成によって
被削材の表面性状を劣化させ、被削性も悪化させるた
め、その上限値を0.4％とした。Si is an element contained in deoxidized upper steel, but if added in excess, it reduces ductility and also deteriorates the surface properties of the work material due to the formation of Si scale, which also deteriorates the machinability. The value was 0.4%.
Mnは、一般に鋼の強度、靭性を確保する上で不可欠な元
素であり、Ｓによる熱間脆性を回避する意味を併せて、
下限を0.20％とした。しかしながら、過度の添加は、加
工性・溶接性を劣化させるため、2.0％以下とした。Mn is an element that is generally indispensable for securing the strength and toughness of steel, and also has the meaning of avoiding hot embrittlement due to S.
The lower limit was 0.20%. However, excessive addition deteriorates workability and weldability, so the content was made 2.0% or less.
Ｐは、一般に鋼中に固溶して生地を脆化させることによ
り被削性を向上させる元素であるが、この量が多いと電
気抵抗溶接性を劣化させる。従って、その上限を0.030
％とした。P is an element that generally improves the machinability by forming a solid solution in steel to embrittle the material, but if this amount is large, the electric resistance weldability deteriorates. Therefore, the upper limit is 0.030.
%.
Ｓは、切屑処理性を改善するために有効な元素である
が、Ｓ量の増大とともに、製管のための電気抵抗溶接の
際の溶接割れ、超音波探傷試験時のUST不良などによる
大幅な歩留低下の原因となるため、その上限値を0.040
％とした。なお、切屑処理性に及ぼすＳとＮの複合効果
を最も有効にし、かつUST不良による歩留落ちを最低限
に抑えたい場合には、0.015％以上、0.025％以下の添加
が望ましい。S is an element effective for improving the chip disposability, but as the amount of S increases, it causes a large amount due to welding cracks during electric resistance welding for pipe manufacturing, UST failure during ultrasonic flaw detection tests, etc. The upper limit is 0.040 as it causes a decrease in yield.
%. It is desirable to add 0.015% or more and 0.025% or less in order to maximize the combined effect of S and N on chip disposability and minimize yield loss due to UST failure.
sol.Alは、一般に脱酸上含まれる元素であり、リムド鋼
ベースのものを考慮して、下限値を0.001％とした。一
方、Alはアルミナクラスターの生成により鋼の被削性を
悪化させる上、AlNの生成により青熱脆性を軽減させ、
またこのAlNの生成は、高温での靭性を低下させるた
め、その上限を0.005％とした。sol.Al is an element generally contained in deoxidation, and the lower limit value was set to 0.001% in consideration of the rimmed steel base. On the other hand, Al deteriorates the machinability of steel by the formation of alumina clusters, and reduces the blue heat brittleness by the formation of AlN,
Moreover, since the formation of AlN lowers the toughness at high temperature, its upper limit was made 0.005%.
Ｎは、被削性に対しても有効な元素である。これは、切
屑の温度がＮによる青熱脆性温度領域に達するため、切
屑の分断性が良くなるというものであり、0.0060％超の
添加でその作用を発揮する。しかしながら、0.0100％を
超えて添加すると溶接性を著しく劣化させることから、
その上限値を0.0100％とした。N is an element effective for machinability. This is because the temperature of the chips reaches the blue-heat embrittlement temperature range due to N, so that the chip-dividing property is improved, and addition of more than 0.0060% exerts its action. However, if added in excess of 0.0100%, the weldability deteriorates significantly,
The upper limit was 0.0100%.
ここで、Ｎが0.0060％超では、通常は溶接性に支障を来
す可能性があるが、本発明ではAlを低く制限することに
より、溶接性悪化の原因となるAlNの発生を低減し、そ
れによる高温脆性を抑制しているので本発明のように溶
接性を損なわない範囲でＮを多量に添加できる。Here, if N exceeds 0.0060%, the weldability may usually be impaired, but in the present invention, by limiting Al to a low level, the generation of AlN that causes deterioration of the weldability is reduced, Since the high temperature brittleness due to this is suppressed, a large amount of N can be added within the range that does not impair the weldability as in the present invention.
Ｏは、前述のＳ量、sol.Al量を前提とした場合、0.0060
％超の添加によって酸化物が増大し、超音波探傷試験時
のUST不良の要因となる上、Ca酸化物を生成することに
より、次に述べる硫化物MnSの形態を制御するためのCa
を少なくするため、その上限を0.0060％とした。O is 0.0060 when the S amount and sol.Al amount described above are assumed.
% Addition of oxide increases the oxide content, which causes UST failure during ultrasonic flaw detection test. In addition, the formation of Ca oxide causes Ca to control the morphology of sulfide MnS described below.
In order to reduce this, the upper limit was made 0.0060%.
Caは、0.002％以上の添加によって、硫化物MnSの形態を
制御し靭性を向上させる効果を有しているほか、酸化物
生成により工具寿命、切削抵抗を良好とする。一方、0.
020％を超えて添加すると大型介在物となり、靭性，電
気抵抗溶接性に悪影響を及ぼす。このため添加量の範囲
を0.002〜0.020％に制限した。When Ca is added in an amount of 0.002% or more, it has the effect of controlling the morphology of sulfide MnS and improving the toughness, and also improves the tool life and cutting resistance by forming oxides. On the other hand, 0.
If added in excess of 020%, it becomes large inclusions, which adversely affects toughness and electric resistance weldability. Therefore, the range of addition amount is limited to 0.002 to 0.020%.
さらに、Ca％／（1.25×Ｏ％＋0.625×Ｓ％）を0.05以
上とすることで、製管のための電気抵抗溶接の際のUST
不良の原因となるMnSの展伸を抑える効果を発揮させる
ことができる。なお、上式の分母はCaがCaSとしてＳと
有効に結びつき硫化物の多くを楕円状化してMnSの展伸
を抑制し、さらに、Ca,Alが有効に結びついて低融点酸
化物CaO・Al2O3を生成するために必要なCa量を表してい
る。Further, by setting Ca% / (1.25 × O% + 0.625 × S%) to 0.05 or more, UST for electric resistance welding for pipe manufacturing
It is possible to exert the effect of suppressing the spread of MnS that causes defects. The denominator of the above equation is that Ca effectively binds S as CaS and makes most of the sulfides elliptical to suppress the spread of MnS. Furthermore, Ca and Al are effectively bound to each other and the low melting point oxide CaO ・ Al It represents the amount of Ca required to generate 2 O 3 .
また、本発明は、機械構造用鋼管の耐食性を考慮して、
0.10％以上のCr,Mo等の合金元素を加えた場合にも有効
であり、炭素鋼をはじめ、各種の合金鋼に対しても適用
し得る。但し、これらの元素についても、多量添加は機
械構造用合金鋼としての被削性を低下させるので、その
上限値をそれぞれ1.50％,0.60％とした。さらに、必要
に応じて、結晶粒を細粒化し靭性を向上させるために、
Nb,W等を含有させることも可能である。また、本発明に
REM（希土類元素）を含有させることにより、機械的性
質を改善させることも可能である。Further, the present invention, considering the corrosion resistance of the steel pipe for machine structure,
It is also effective when adding 0.10% or more of alloying elements such as Cr and Mo, and can be applied to various alloy steels including carbon steel. However, also for these elements, the addition of a large amount reduces the machinability of the alloy steel for machine structural use, so the upper limits were set to 1.50% and 0.60%, respectively. Further, if necessary, in order to refine the crystal grains and improve the toughness,
It is also possible to contain Nb, W, etc. In addition, in the present invention
It is also possible to improve mechanical properties by incorporating REM (rare earth element).
本発明に従い前記の化学成分で構成された鋼は、転炉、
電気炉などで溶製され、造塊−分塊、あるいは連続鋳造
の工程を経て、熱間圧延される。この後に、必要に応じ
て冷間圧延を施され、管成形−電気抵抗溶接された後、
必要に応じて所定の熱処理を受け、機械構造用鋼管とし
て使用される。According to the present invention, the steel composed of the above chemical composition is a converter,
It is melted in an electric furnace or the like, and is hot-rolled through a process of ingot-segmentation or continuous casting. After this, if necessary, cold-rolled, after pipe forming-electric resistance welding,
If necessary, it is subjected to a predetermined heat treatment and used as a steel pipe for machine structures.
（実施例） 第１表は、本発明を実施するにあたって使用に供した鋼
の化学組成を示したものである。第１表に示した成分の
鋼を溶製、連続鋳造、熱間圧延を行った後、電気抵抗溶
接を行い、φ50.8×t5.0mmの電気抵抗溶接管を製造し
た。また、製管後の全ての管について、超音波探傷（US
T）を実施した。この際のUSTの歩留値と実用試験結果に
ついて第２表に示す。さらに、製管後、必要に応じて熱
処理を行ない、旋盤によって切削試験を実施した。その
結果も併せて、第２表に示す。これらの結果をまとめ
て、模式的に第１図に示す。(Example) Table 1 shows the chemical composition of the steel used for practicing the present invention. Steel having the components shown in Table 1 was melted, continuously cast, and hot-rolled, and then electric resistance welding was performed to produce an electric resistance welded pipe of φ50.8 × t5.0 mm. In addition, ultrasonic flaw detection (US
T) was carried out. Table 2 shows the yield value of UST and the results of practical tests at this time. Further, after the pipe was manufactured, a heat treatment was performed if necessary, and a cutting test was performed by a lathe. The results are also shown in Table 2. These results are summarized and shown schematically in FIG.
なお、切削試験は、回転数300〜800RPM、送り0.10〜0.5
0mm/rev.、切削速度50〜200mm/min.、切込み1.5mmの切
削条件で超硬工具を用いて実施し、切屑を採取した。こ
こで、切屑処理性指数は、切屑長さ50mm以下が得られる
条件数の全条件数に対する百分率で示した。In the cutting test, the rotation speed is 300 to 800 RPM, and the feed is 0.10 to 0.5.
Chips were collected by using a cemented carbide tool under the cutting conditions of 0 mm / rev., Cutting speed 50 to 200 mm / min., And depth of cut of 1.5 mm. Here, the chip disposability index is shown as a percentage of the total number of conditions for obtaining a chip length of 50 mm or less.
第２表、及び、第１図より、Ｓレベルの低い従来の機械
構造用電気抵抗溶接鋼管は、UST時の歩留は良好である
が、切屑処理性が劣ること、Ｓレベルの高い従来の快削
鋼を素材とした場合には、切屑処理性は良好であるが、
UST時の歩留が著しく劣ることがわかる。さらに、S,N,C
a,Oの量を、本発明で示した範囲に特定することによ
り、歩留を著しく低下させることなく、切屑処理性の良
好な電気抵抗溶接鋼管を製造することが可能であること
がわかる。From Table 2 and Fig. 1, the conventional electric resistance welded steel pipe for machine structure having a low S level has a good yield at UST, but has poor chip disposability and has a high S level. If free-cutting steel is used as the material, chip disposability is good,
It can be seen that the yield at UST is significantly inferior. Furthermore, S, N, C
It is understood that by specifying the amounts of a and O within the ranges shown in the present invention, it is possible to manufacture an electric resistance welded steel pipe having good chip disposability without significantly reducing the yield.
（発明の効果） 以上の実施例からも分かるように、N,S,Ca,Oの量を、本
発明で示した範囲に特定することにより、UST時の歩留
の低下はほとんどない。本発明により、被削性の優れた
機械構造用電気抵抗溶接鋼管を製造することが可能とな
った。 (Effects of the Invention) As can be seen from the above examples, by specifying the amounts of N, S, Ca, and O within the ranges shown in the present invention, there is almost no decrease in the yield during UST. According to the present invention, it has become possible to manufacture an electric resistance welded steel pipe for machine structure having excellent machinability.
第１図は、本発明の効果について、模式的に示したもの
である。FIG. 1 schematically shows the effect of the present invention.
フロントページの続き (56)参考文献 特開 昭56−142850（ＪＰ，Ａ) 特開 昭57−140854（ＪＰ，Ａ) 特開 昭54−163716（ＪＰ，Ａ) 特開 平３−177539（ＪＰ，Ａ)Continuation of the front page (56) Reference JP-A-56-142850 (JP, A) JP-A-57-140854 (JP, A) JP-A-54-163716 (JP, A) JP-A-3-177539 (JP , A)
Claims (2)
特徴とする被削性の優れた機械構造用電気抵抗溶接鋼
管。[Claim 1] C: 0.02 to 0.60%, Si: 0.4% or less, Mn: 0.20 to 2.0%, P: 0.030% or less, S: 0.040% or less, sol.Al: 0.001 to 0.005% in weight% N: more than 0.0060% and 0.0100% or less, O: 0.0060% or less, Ca: 0.002 to 0.020% and contains Ca% / (1.25 × O% + 0.625 × S%) ≧ 0.05, balance iron and unavoidable impurities An electric resistance welded steel pipe for machine structure with excellent machinability.
特徴とする被削性の優れた機械構造用電気抵抗溶接鋼
管。2. In weight% display, C: 0.02 to 0.60%, Si: 0.4% or less, Mn: 0.20 to 2.0%, P: 0.030% or less, S: 0.040% or less, Cr: 0.10 to 1.50%, Mo: 0.10 to 0.60%, sol.Al: 0.001 to 0.005%, N: more than 0.0060% and 0.0100% or less, O: 0.0060% or less, Ca: 0.002 to 0.020% and Ca% / (1.25 x O% + 0.625 x S %) ≧ 0.05 and the balance is composed of iron and unavoidable impurities, and is an electric resistance welded steel pipe for machine structure with excellent machinability.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020177A JPH0774413B2 (en) | 1990-01-30 | 1990-01-30 | Electric resistance welded steel pipe for machine structure with excellent machinability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2020177A JPH0774413B2 (en) | 1990-01-30 | 1990-01-30 | Electric resistance welded steel pipe for machine structure with excellent machinability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03226545A JPH03226545A (en) | 1991-10-07 |
| JPH0774413B2 true JPH0774413B2 (en) | 1995-08-09 |
Family
ID=12019898
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2020177A Expired - Lifetime JPH0774413B2 (en) | 1990-01-30 | 1990-01-30 | Electric resistance welded steel pipe for machine structure with excellent machinability |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0774413B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EA008418B1 (en) * | 2003-05-28 | 2007-04-27 | Сумитомо Метал Индастриз, Лтд. | Oil well steel pipe to be placed under ground and be expanded |
| CN112342464B (en) * | 2020-10-19 | 2021-07-27 | 中天钢铁集团有限公司 | Production method of free-cutting steel hot-rolled wire rod for OA (office automation) shaft |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54163716A (en) * | 1978-06-16 | 1979-12-26 | Sumitomo Metal Ind | Structural electroforming steel pipe with excellent cutting workability |
| JPS56142850A (en) * | 1980-04-09 | 1981-11-07 | Nippon Steel Corp | Steel for mechanical structure having excellent grindability and cold processability |
| JPS57140854A (en) * | 1981-02-23 | 1982-08-31 | Nippon Steel Corp | Machine structural steel with superior machinability |
| JPH07116554B2 (en) * | 1989-12-07 | 1995-12-13 | 新日本製鐵株式会社 | Electric resistance welded steel pipe for machine structure with excellent machinability |
-
1990
- 1990-01-30 JP JP2020177A patent/JPH0774413B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03226545A (en) | 1991-10-07 |
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