JPS6037173B2 - Method for manufacturing an electric resistance welded steel pipe having an electric resistance welded part with excellent groove corrosion resistance - Google Patents
Method for manufacturing an electric resistance welded steel pipe having an electric resistance welded part with excellent groove corrosion resistanceInfo
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- JPS6037173B2 JPS6037173B2 JP1476177A JP1476177A JPS6037173B2 JP S6037173 B2 JPS6037173 B2 JP S6037173B2 JP 1476177 A JP1476177 A JP 1476177A JP 1476177 A JP1476177 A JP 1476177A JP S6037173 B2 JPS6037173 B2 JP S6037173B2
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- corrosion resistance
- electric resistance
- resistance welded
- groove corrosion
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Description
【発明の詳細な説明】
本発明は耐溝食性のすぐれた露縫部を有する亀縫鋼管の
製造方法、可酷な環境においても充分な耐溝食性を具え
る露縫部を有する亀縫鋼管の製造方法に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for manufacturing a hemlock-stitched steel pipe having an exposed seam portion with excellent groove corrosion resistance, and a method for manufacturing a hemlock-stitched steel pipe having an open seam portion that has sufficient groove corrosion resistance even in harsh environments. It is about the method.
近来、霞総鋼管は製造技術が向上し、製品が低価格化し
たこともあって、その需要は増大し、便用分野も拡大さ
れている。In recent years, the manufacturing technology of Kasumi Steel Pipe has improved and the product has become cheaper, so the demand for it has increased and its useful fields have expanded.
このため、一般配管用電縫鋼管も多量に使用されるよう
になり、それに応じて、使用環境も海水、水道水、ブラ
ィンあるいは酸性水等多くの腐食環境でも使用されるよ
うになっている。しかしながら、このような腐食環境下
においては、雷総部は溝食を受け、ついには漏洩に至り
、このため、霧総鋼管の耐用年数は母材部の腐食減量よ
り予測される耐用年数よりはるかに短い期間になって、
この耐用年数の数分の一程度になる。たとえば、海水を
使用した給排水配管あるいは冷却水配管として電縫鋼管
を使用する場合は、使用後2年以内で雷縫部に溝食が発
生して穿孔しそれによる洩水等の事故が多くなっている
。このため、露縫部の溝食を防止する手段として、従来
から帯鋼の低S化、耐溝食性向上合金元素を添加した鋼
種等が提案実施され、更に、電縫部を溶接後に熱処理し
て耐溝食性を向上させることも知られているが、何れの
手段でも十分に満足すべきものは見当らない。For this reason, electric resistance welded steel pipes for general piping have come to be used in large quantities, and accordingly, they have come to be used in many corrosive environments such as seawater, tap water, brine, and acidic water. However, in such a corrosive environment, the steel pipe suffers from groove corrosion, eventually leading to leakage, and as a result, the service life of Kirisou steel pipe is much longer than the service life predicted from the corrosion loss of the base material. After a short period of time,
This will be about a fraction of this useful life. For example, when using electric resistance welded steel pipes for water supply and drainage piping or cooling water piping that uses seawater, there are many accidents such as groove corrosion and perforation in the seams within two years of use, resulting in water leakage. There is. For this reason, as a means to prevent groove corrosion at the open seam, proposals have been made to reduce the S content of steel strips and to add alloying elements to improve groove corrosion resistance. It is also known to improve groove corrosion, but none of these methods have been found to be fully satisfactory.
すなわち、現行の耐鋼を単に低S化処理したのみでは、
溝食防止は困難あり、特に、激しい腐食環境下では一般
工程材とほぼ同程度の溝食が生じ、低S化処理のみで耐
溝食性を向上させることは困難に近い。In other words, if the current steel is simply subjected to low-S treatment,
It is difficult to prevent groove corrosion, and in particular, in a severely corrosive environment, groove corrosion occurs to the same degree as general process materials, and it is almost difficult to improve groove corrosion resistance only by low-S treatment.
また、耐溝食性合金元素を添加すると、耐溝食性を具え
る雷縫鋼管が得られるが、霞縫鋼管は高級化し、コスト
高になるのが欠点である。Further, by adding a groove corrosion-resistant alloying element, a thunder weave steel pipe having groove corrosion resistance can be obtained, but the disadvantage is that the thunder seam steel pipe becomes high quality and expensive.
また、溶接後に蚤縫部を熱処理すると、耐溝食性が向上
し、とくに、一般工程材および低S鋼においては高温度
で長時間蟹縫部を焼なましすると、耐溝食性が向上する
。Furthermore, heat treatment of the crammed portion after welding improves the groove corrosion resistance, and in particular, in general process materials and low S steel, annealing the crib stitched portion at high temperature for a long period of time improves the groove corrosion resistance.
しかしながら、このように長時間で高温の熱処理では現
工程には適合せず、現工程に適合しかつ経済的な熱処理
条件の設定が望まれている。本発明は上記欠点の解決を
目的とし、特に、溶接後きわめて短時間熱処理するのみ
で耐溝食性のきわめてすぐれた電総部を有する露縫鋼管
の製造方法を提案する。However, such long-time and high-temperature heat treatment is not suitable for the current process, and it is desired to set economical heat treatment conditions that are suitable for the current process. The present invention aims to solve the above-mentioned drawbacks, and in particular proposes a method for manufacturing open-seam steel pipes having an electrically welded section that exhibits excellent groove corrosion resistance by only requiring a very short heat treatment after welding.
以下、本発明法について詳しく説明する。The method of the present invention will be explained in detail below.
まず、本発明法においては、低S化されしかも希±類に
含まれる元素のうちの少なくとも一種が含まれる帯鋼ま
たはこれに更にCuを添加した帯鋼を素材とし、これら
帯鋼を常法によって縫合せ溶接によって造管した電縫鋼
管を製造する。First, in the method of the present invention, a steel strip containing at least one of the rare elements or a steel strip to which Cu is added is used as a raw material, and these steel strips are processed using a conventional method. We manufacture electric resistance welded steel pipes by seam welding.
この場合、これら帯鋼はその組成が後記の如く熱処理条
件と深い関連を持っており、このため、帯鋼は、CO.
3重量%(以下単に%で示す)Sil.0%以下、Mn
o.2〜1.2%、SO.01%以下、PO.04%以
下、ならびにAIO.01〜0.10%を含むと共に、
希土類元素たるランタニド元素のうちで少なくとも一種
0.005〜0.1%を含み、残余が実質的にFeから
成ることを必要とし、しかも、この組成であると、後記
の実施例にも示す如く、山0.01〜0.10%を含む
場合にも、耐溝食性が大中に改善される。また、更に、
帯鋼は、この残余の一部がCuo.05〜0.5%で置
換されたものであることを必要とする。次に、上記の通
りの組成の帯鋼から霞縫鋼管を造管し、その後、小なく
ともその亀縫部は850℃〜950ooで焼なまして熱
処理する。このように熱処理すると、焼準温度が比較的
低くかつ例えば1〜2分程度の時間であるにも拘らず、
この熱処理によってきわめて耐溝食性にすぐれる竜縫部
を有する雷縫鋼管が得られる。そこで、この理由につい
て説明すると、次の通りである。In this case, the composition of these steel strips is closely related to the heat treatment conditions as described below, and therefore, the steel strips have a CO.
3% by weight (hereinafter simply expressed as %) Sil. 0% or less, Mn
o. 2-1.2%, SO. 01% or less, PO. 04% or less, and AIO. Contains 01-0.10% and
It is necessary to contain 0.005 to 0.1% of at least one kind of lanthanide element, which is a rare earth element, and the remainder to be substantially composed of Fe, and with this composition, as shown in the examples below. , 0.01 to 0.10% of ridges also improve groove corrosion resistance. Moreover, furthermore,
In the steel strip, a part of this residue is Cuo. 05 to 0.5%. Next, a welded steel pipe is formed from the strip steel having the composition as described above, and then at least the helmeted portion thereof is annealed and heat treated at 850° C. to 950° C. When heat treated in this way, even though the normalization temperature is relatively low and the time is about 1 to 2 minutes,
By this heat treatment, a lightning weave steel pipe having a dragonfly portion with extremely excellent groove corrosion resistance can be obtained. The reason for this will be explained as follows.
まず、第1図ならびに第2図は種々の露縫鋼管について
温度50qo、酸素雰囲気(溶存酸素約15ppm)流
速25m/minの人工海水中の如き、可酷な腐食環境
において溝食と熱処理条件との相関関係を示したもので
ある。First, Figures 1 and 2 show groove corrosion and heat treatment conditions for various open-seam steel pipes in a harsh corrosive environment such as artificial seawater at a temperature of 50 qo, an oxygen atmosphere (dissolved oxygen approximately 15 ppm), and a flow rate of 25 m/min. This shows the correlation between
この結果から明らかな通り、一般工程材から成る露縫鋼
管は、焼準温度以上の温度で長時間焼なましすると耐溝
食性が向上し、また、低S材から成る露縫鋼管の耐溝食
性は一般工程材よりは低温でかつ短時間の熱処理により
向上するが、不完全であり、通常の暁準温度以上でない
と、耐溝食性は向上せず、単に低S化したのみの帯鋼を
素材とする場合は、短時間で比較的低温度で熱処理する
ことに適さない。As is clear from these results, the groove corrosion resistance of open-sewn steel pipes made of general process materials improves when annealed for a long time at temperatures above the normal temperature, and the groove resistance of open-sewn steel pipes made of low-S materials improves. Corrosion resistance is improved by heat treatment at a lower temperature and for a shorter time than that of general process materials, but it is incomplete, and groove corrosion resistance does not improve unless the temperature is above the normal dawn sub-temperature, and it is a steel strip that has only been made low in S. is not suitable for heat treatment at relatively low temperatures for a short period of time.
しかしながら、本発明方法では、SO.001%以下で
希士類に含まれる少なくとも一種を添加した帯鋼(第1
図、第2図では低S十REM系として示す)若しくは、
これを更にCuを添加した帯鋼(第1図、第2図では低
S+REM+Cu系として示す。However, in the method of the present invention, SO. Steel strip containing at least one type of rare metal added at 0.001% or less (No. 1
(shown as a low S1REM system in Figure 2) or
This is a steel strip to which Cu is further added (in FIGS. 1 and 2, it is shown as a low S+REM+Cu series).
)から露縫鋼管をつくるため、これら電縫鋼管は850
oo〜95000の温度範囲できわめて短時間の焼なま
し処理すると、耐溝食性が飛躍的に向上する。また、第
1図ならびに第2図から明らかな通り、このように本発
明法で製造される霜縫鋼管は、高温、高流速の酸性水あ
るいは汚染海水等の如く、可酷な腐食環境においても有
効であって、この際の熱処理条件はシームアニーリング
の如き現工程においても容易に実現できる。以上の通り
、本発明法で製造される露総鋼管は耐溝食性に優れるも
のであるが、この理由を海水中における溝食の進行状況
に基づいて溝食の機構、添加元素および熱処理効果との
関連で詳しく説明すると、次の通りである。), these ERW steel pipes are made from 850
An extremely short annealing treatment in the temperature range of 0 to 95,000 ℃ dramatically improves the groove corrosion resistance. Furthermore, as is clear from FIGS. 1 and 2, the frost-sewn steel pipe manufactured by the method of the present invention can withstand severe corrosive environments such as high temperature, high flow rate acidic water or contaminated seawater. This is effective, and the heat treatment conditions at this time can be easily realized in current processes such as seam annealing. As mentioned above, exposed steel pipes manufactured by the method of the present invention have excellent groove corrosion resistance.The reason for this can be explained based on the progress of groove corrosion in seawater, the mechanism of groove corrosion, additive elements, and heat treatment effects. A detailed explanation in relation to this is as follows.
まず、帯鋼の総合せ熔接時に、その蚤総部には、溶接時
のアップセットによってメタルフロー層間に存在するM
nS系若しくはMn−○−S系の非金属介在物が集積す
る。この介在物は溶接時の溶触過程で融解(融点162
0q0)するが、続いて急激に冷却されるため、該介在
物は再析出できず、該介在物の近傍の地鉄には固溶Sが
残留し、これが腐食の起点になって、溝食に成長するも
のと思われる。これに対して、本発明法では、低Sでし
かも希士類に属する少なくとも一種の元素を含む帯鋼か
ら製造するため、上記の通りに有害なA系MnS系等の
非金属介在物は減少し、希土類の元素がMnに優先して
Sと結合して希±類−S若しくは希土類一〇一SのBあ
るいはC系ラ ム物を生成してSを固定する。また、
更に、本発明法ではこれにCuを添加したものから製造
しているため、上記希士類の効果は相乗的に高められ、
一方では局部腐食が抑制され、このため、耐溝食性が増
大する。First, during comprehensive welding of steel strips, there is a M
Nonmetallic inclusions of nS type or Mn-○-S type accumulate. These inclusions melt during the contact process during welding (melting point: 162
However, due to subsequent rapid cooling, the inclusions are unable to re-precipitate, and solid solution S remains in the base steel near the inclusions, which becomes the starting point for corrosion and groove corrosion. It is expected that it will grow to. On the other hand, in the method of the present invention, since the steel strip is manufactured from a steel strip that is low in S and contains at least one element belonging to the rare group, harmful non-metallic inclusions such as A-based MnS-based materials are reduced as described above. However, rare earth elements combine with S preferentially over Mn to form B or C-based ram products of rare -S or rare earth 101S, thereby fixing S. Also,
Furthermore, in the method of the present invention, since Cu is added to the product, the effects of the rare metals are synergistically enhanced.
On the one hand, local corrosion is suppressed, thus increasing the groove corrosion resistance.
また、このような状態において本発明法によって少なく
とも露縫部を熱処理すると、露縫部の固溶Sの拡散速度
は速められ、非金属介在物が容易に再析出し、腐食活性
な固溶Sが減少して、腐食不活性化され、電縫部の耐溝
食性は向上する。In addition, when at least the open seam part is heat-treated by the method of the present invention in such a state, the diffusion rate of solid solution S in the open seam part is accelerated, nonmetallic inclusions are easily reprecipitated, and corrosion-active solid solution S is reduced. As a result, corrosion is inactivated, and the groove corrosion resistance of the electric resistance welded portion is improved.
以上要するに本発明法は低Sでしかも希土類に属する少
なくとも一種の元素、更に、これに加えてCuという合
金元素の存在に関連させて熱処理し、これによって、耐
溝食性にきわめて優れた電縫鋼管を製造するものである
が、この特長から、本発明法は例えばシームアニールの
如き現製造工程で容易に実現でき、また、この熱処理に
よって亀縫部の耐溝食性を飛躍的に向上させることがで
きる。次に、本発明法における熱処理条件に示すと、次
の通りである。In summary, the method of the present invention is a low-sulfur, heat-treated steel pipe that is associated with the presence of at least one element belonging to the rare earth group and an alloying element called Cu in addition to this. Due to this feature, the method of the present invention can be easily realized using current manufacturing processes such as seam annealing, and this heat treatment can dramatically improve the groove corrosion resistance of the seam seams. . Next, the heat treatment conditions in the method of the present invention are as follows.
まず、本発明法において、造管後、少なくとも露縫部は
850℃〜95000で熱処理する。First, in the method of the present invention, after pipe making, at least the exposed seam portion is heat treated at 850°C to 95,000°C.
すなわち、85000以下では熱処理が不十分で可酷な
腐食環境に耐える充分な耐溝食性を得ることが困難であ
り、更に、軍総部と母材部の組織も溶接のままの不均一
組織になって、局部電池が形成され、かえって溝食が助
長され易い。また、熱処理温度を950℃以上にしても
、耐溝食性効果は85000〜95000のものとかわ
らず、電縫部と母材部の組織は均一であっても、かえっ
て粗大化したフェライトパーラィト組織が生成し機械的
性質が劣化する。In other words, if the temperature is less than 85,000, the heat treatment is insufficient and it is difficult to obtain sufficient groove corrosion resistance to withstand a harsh corrosive environment.Furthermore, the structure of the main part and base metal part becomes a non-uniform structure similar to that of welding. As a result, local batteries are formed, which tends to promote groove corrosion. In addition, even if the heat treatment temperature is 950°C or higher, the groove corrosion resistance effect is still 85,000 to 95,000, and even though the structure of the electric resistance welding part and the base metal part is uniform, the ferrite-pearlite structure becomes coarser. formation and deterioration of mechanical properties.
この点、本発明の如く、85000〜950qoで熱処
理すると、雷縫部と母材部の組織は均一で紬粒化したフ
ェライトパーラィト組織になり機械的性質は全く低下し
ない。In this regard, when the heat treatment is performed at 85,000 to 950 qo as in the present invention, the structure of the thunder seam portion and the base material portion becomes a uniform ferrite-pearlite structure with pongee grains, and the mechanical properties do not deteriorate at all.
また、この条件であると、熱処理はきわめて短時間で達
成でき、例えば、現工程のシームァニールの如く、1分
以内程度で充分な耐溝食性が得られる。Further, under these conditions, the heat treatment can be accomplished in an extremely short time, and, for example, sufficient groove corrosion resistance can be obtained within about one minute, as in the case of seam annealing in the current process.
次に、本発明法において、素材としての帯鋼の成分限定
理由について述べると、次の通りである。Next, in the method of the present invention, the reasons for limiting the composition of the steel strip as a material are as follows.
希土類に属する元素は何れもMnよりもSに対する結合
力が強く、有害なMnS系等のA系非金属介在物は、R
EM−S系等の微細でしかも分散度の高いB,C系非金
属介在物に変換され、形状制御される。All rare earth elements have a stronger binding force to S than Mn, and harmful A-based nonmetallic inclusions such as MnS-based
It is converted into fine, highly dispersed B, C-based nonmetallic inclusions such as EM-S, and its shape is controlled.
また、希±類に属する元素は低S領域で上記の通りに熱
処理されると、腐食活性な固溶Sは不活性化され、しか
も、この懐向は著しく促進され、飛躍的に耐溝食性が向
上する。In addition, when rare elements are heat-treated in the low S region as described above, the corrosion-active solid solution S is inactivated, and this redirection is significantly promoted, dramatically improving the groove corrosion resistance. will improve.
しかしながら、このような効果は、0.005%未満で
はほとんどなく、0.1%きこえると製鋼上、熱間加工
性および溶接性を阻害し、このため、0.005〜0.
1%が好適である。However, such an effect is hardly seen at less than 0.005%, and when it exceeds 0.1%, hot workability and weldability are inhibited in steel manufacturing, and therefore, when the content is less than 0.005% to 0.005%, hot workability and weldability are inhibited.
1% is preferred.
なお、この希±類に属する元素つまり希±類元素は単独
で添加されずにミッシュメタルの如く2種類以上の合金
組成物として添加され、しかも、本質的な希士類元素た
るランタニド元素を示し、後記の実施例におけるREM
もミッシュメタル中に含まれるランタニド元素の総計を
示す。Furthermore, elements belonging to this rare group, that is, rare elements, are not added alone, but as an alloy composition of two or more types, such as misch metal, and moreover, they represent lanthanide elements, which are essential rare elements. , REM in the examples below
also indicates the total amount of lanthanide elements contained in mischmetal.
Cuは元来耐溝食性を有する元素であるが、通常のS含
有量(S>0.001%)ではその効果が小さい。Cu is an element that originally has groove corrosion resistance, but its effect is small at normal S content (S>0.001%).
しかし、本発明法の如く、低Sで希土類の元素が添加さ
れたものにCuを添加し、更に、上記の通りに熱処理す
ると、相乗的に耐溝食性は向上し、更に、Cuは、耐候
性あるし、は耐酸性を有し、局部腐食を減少させ滑らか
な腐食面を形成する。しかしながら、0.05%未満で
はこのような効果は顕著でなく、また0.5%を越える
と造塊、圧延時の表面欠陥あるいは表面癖など生じて熱
間加工性を劣化させるので、Cuは0.05〜0.5%
とした。AI添加は雷総部の耐溝食性を向上させるとと
もに露縫部の組織の均一性に大きな影響を与えるが添加
量0.01未満では霞縫部の組織が不均一になり耐溝食
性向上に効果がない。However, as in the method of the present invention, when Cu is added to a material with low S and rare earth elements added, and further heat treated as described above, the groove corrosion resistance is synergistically improved. It has acid resistance, reduces local corrosion and forms a smooth corrosion surface. However, if Cu is less than 0.05%, this effect is not noticeable, and if it exceeds 0.5%, surface defects or surface irregularities occur during agglomeration and rolling, deteriorating hot workability. 0.05-0.5%
And so. Addition of AI improves the groove corrosion resistance of the threaded part and has a great effect on the uniformity of the structure of the exposed seam part, but if the addition amount is less than 0.01, the structure of the threaded part becomes uneven and is not effective in improving the groove corrosion resistance. do not have.
しかし、0.10%をこえて添加すると亀縫部の耐溝食
性は増大するが、組織の粗大化をきたし、機械的性質を
損なう。この理由で、山添加量は0.01〜0.10%
に限定する。Cは溶接性、籾性および耐食性に影響を与
える元素であり、0.3%を越えると、溶接性、級性、
耐食性を低下せしめるので上限を0.3%とした。However, if more than 0.10% is added, the groove corrosion resistance of the hexagonal seams increases, but the structure becomes coarser and the mechanical properties are impaired. For this reason, the amount of addition is 0.01 to 0.10%.
limited to. C is an element that affects weldability, grain quality, and corrosion resistance, and if it exceeds 0.3%, weldability, grain quality,
Since it lowers corrosion resistance, the upper limit was set at 0.3%.
Siは脱酸作用があり、耐食性において有効な元素であ
るが、1.0%を越えると溶接性、加工性に悪影響を及
ぼすので上限を1.0%とした。MnはSiと同様に脱
酸作用があり、機械は強度を高めるとともに熱間加工性
および溶接性を向上させる有効な元素である。しかし、
0.2%未満では上記効果は小さく、また1.2%をこ
えると耐食性が悪化するので下限を0.2%、上限を1
.2%とした。Sは耐溝食性に対しもっとも有害な元素
であり、なるべく少ないのが好ましいが、完全に除去す
ることは不可能で、低減の程度に目から限度がある。Si has a deoxidizing effect and is an effective element for corrosion resistance, but if it exceeds 1.0%, it has a negative effect on weldability and workability, so the upper limit was set at 1.0%. Like Si, Mn has a deoxidizing effect, and is an effective element that increases mechanical strength and improves hot workability and weldability. but,
If it is less than 0.2%, the above effect will be small, and if it exceeds 1.2%, the corrosion resistance will deteriorate, so the lower limit should be 0.2% and the upper limit should be 1%.
.. It was set at 2%. S is the most harmful element to groove corrosion resistance, and although it is preferable to reduce it as much as possible, it is impossible to completely remove it, and there is a limit to how much it can be reduced.
しかし0.01%を越えるとMnS系非金属介在物が鋼
中に多量に存在し、耐溝食性を著しく阻害するので、上
限は0.01%にした。Pは多量に添加すると、耐溝食
性を向上させるが、一方、溶接性および鋤性が損なわれ
る。However, if it exceeds 0.01%, a large amount of MnS-based nonmetallic inclusions will exist in the steel, which will significantly impede groove corrosion resistance, so the upper limit was set at 0.01%. When P is added in a large amount, it improves groove corrosion resistance, but on the other hand, weldability and plowability are impaired.
このため、本発明では上限は0.04%にした。以上詳
しく説明した通り、本発明法は、SO.01%以下の低
S条件のところに希±類に属する少なくとも一種の元素
を添加して帯鋼、または、低Sでしかも希土類の元素と
ともにCuを含む帯鋼から造管し、その後、少なくとも
、露縫部を糠なまして熱処理し、きわめて優れた耐溝食
性を具える露縫部を有する亀総鋼管を製造する方法であ
る。以下、実施例について説明する。まず、本発明法に
よる場合の4種の帯鋼(試験番号D〜G)と従来法によ
る場合の3種の帯鋼(試験番号A〜C)とを常法によっ
てシーム溶接して7種の露縫鋼管をつくり、その後、6
30〜1200qoの熱処理温度で10分間熱処理し、
その後、空気中で放冷した。Therefore, in the present invention, the upper limit is set to 0.04%. As explained in detail above, the method of the present invention is applicable to SO. A steel strip is produced by adding at least one element belonging to the rare earth group under a low S condition of 0.01% or less, or a pipe is made from a steel strip that is low in S and contains Cu together with a rare earth element, and then at least This is a method for manufacturing Kameso steel pipes having exposed seams that have extremely excellent groove corrosion resistance by annealing and heat-treating the open seams. Examples will be described below. First, four types of steel strips (test numbers D to G) using the method of the present invention and three types of steel strips (test numbers A to C) using the conventional method were seam welded using a conventional method. Make open-seam steel pipe, then 6
Heat treated for 10 minutes at a heat treatment temperature of 30 to 1200 qo,
Thereafter, it was left to cool in the air.
次に、これら電総鋼管の各電縫部について、可酷な環境
で腐食試験をしたところ、耐溝食性については、第1表
の通りの結果が得られた。Next, a corrosion test was conducted on each electric resistance welded portion of these electric steel pipes in a harsh environment, and the results shown in Table 1 regarding groove corrosion resistance were obtained.
この腐食試験は、温度50q0、酸素雰囲気(約15p
pm02)の人工海水中の如く可酪な環境で、周速度2
5仇/minの回転浸贋型腐食試験機を用いて3ケ月の
試験期間で行った。This corrosion test was carried out at a temperature of 50q0 and an oxygen atmosphere (approximately 15p
pm02) in a stable environment such as artificial seawater, the circumferential speed is 2.
The test was conducted over a three-month period using a rotary immersion type corrosion tester at a rate of 5 min/min.
用いた試験材は、6私および10Mの露縫鋼管から採取
した。船船
ヤ
蟻
磯
旧
ゆ
こ
が
仲
¥
蓮
3
蓋
戊
世
なお、第1表において耐食発生状況は次の第2表で示す
符号にもとづいて示した。The test materials used were taken from 6I and 10M open seam steel pipes. In addition, in Table 1, the occurrence of corrosion resistance is indicated based on the codes shown in Table 2 below.
2
以上のところから明らかな通り、従釆法で製造するとき
にSが一般工程、材程度の場合は熱処理時間10である
と、熱処理温度を1100oo以上の高温にしないと、
耐溝食性を有する露縫部が得られない。2. As is clear from the above, when S is a general process or a material grade when manufactured by the secondary method, if the heat treatment time is 10, the heat treatment temperature must be set to a high temperature of 1100 oo or higher.
It is not possible to obtain open seams with groove corrosion resistance.
また、従来法であっても一般工程材よりSを低減させた
場合は920oo〜1000oo以上程度で耐溝食性を
有する電燈部が得られる。これに対し、本発明法によっ
て製造する場合は、何れの場合でも、85000以上で
亀縫部の耐溝食性は良好になつた。また、本発明法で熱
処理時間を1分以内にして製造したところ、この場合も
上記のところと同等の結果が得られた。Furthermore, even with the conventional method, if the S content is lower than that of the general process material, a light part having groove corrosion resistance of about 920 oo to 1000 oo or more can be obtained. On the other hand, in the case of manufacturing according to the method of the present invention, the groove corrosion resistance of the hexagonal seam portion became good in all cases at 85,000 or more. Further, when the film was manufactured using the method of the present invention with the heat treatment time being within 1 minute, results similar to those described above were obtained in this case as well.
また、上記の通りに本発明法によって製造した霞総管に
ついて、腐食雰囲気をかえて汚染海水、汚染河川水ある
いは酸性水を用い、それぞれにつき高温、高流速(50
00、約15ppm02、25m/min)の如き可酪
な腐食環境を設定して、この中において試験したところ
、上甑と同等な耐食状況が得られ、本発明法による場合
は従釆法のものよりも耐溝食性がすぐれていた。In addition, for the Kasumi pipe manufactured by the method of the present invention as described above, the corrosive atmosphere was changed to contaminated seawater, contaminated river water, or acidic water.
00, approximately 15ppm02, 25m/min), and when tested in this environment, the same corrosion resistance as that of the upper layer was obtained, and the method of the present invention was better than that of the conventional method. It also had excellent groove corrosion resistance.
また、本発明法で製造される露縫鋼管につき、その溶接
性および機械的性質についてしらべたところ、一般工程
材のものと同様に良好なものであつた。Furthermore, when the weldability and mechanical properties of the open-seamed steel pipe manufactured by the method of the present invention were examined, they were found to be as good as those of general process materials.
第1図ならびに第2図はそれぞれ本発明法における帯鋼
化学組成、熱処理条件ならびに耐溝食性の関係を示すグ
ラフである。
第1図
第2図FIGS. 1 and 2 are graphs showing the relationship between the chemical composition of the steel strip, heat treatment conditions, and groove corrosion resistance in the method of the present invention, respectively. Figure 1 Figure 2
Claims (1)
Mn0.2〜1.2%、P0.04%以下、S0.01
%以下ならびにAl0.01〜0.10%を含むと共に
、希土類元素たるランタニド元素のうちの少なくとも一
種0.005〜0.1%を含み、残余が実質的にFeか
ら成る帯鋼を縫合せ溶接で接合して造管し、その後、こ
の電縫部を850℃〜950℃で加熱して焼なますこと
を特徴とする耐溝食性のすぐれた電縫部を有する電縫鋼
管の製造方法。 2 重量百分率でC0.3%以下、Si1.0%以下、
Mn0.2〜1.2%、P0.04%以下、S0.01
%以下ならびにAl0.01〜0.10%を含むと共に
、希土類元素たるランタニド元素のうち少なくとも一種
0.005〜0.1%ならびにCu0.05〜0.5%
を含み、残余が実質的にFeから成る帯鋼を縫合せ溶接
で接合して造管し、その後、この電縫部を850℃〜9
50℃で加熱して焼なますことを特徴とする耐溝食性の
すぐれた電縫部を有する電縫鋼管の製造方法。[Claims] 1. C0.3% or less, Si 1.0% or less in weight percentage,
Mn0.2-1.2%, P0.04% or less, S0.01
% or less and 0.01 to 0.10% of Al, and 0.005 to 0.1% of at least one of the lanthanide elements, which are rare earth elements, with the remainder substantially consisting of Fe. 1. A method for manufacturing an electric resistance welded steel pipe having an electric resistance welded part with excellent groove corrosion resistance, characterized in that the electric resistance welded part is joined at 850° C. to 950° C. to form a pipe, and then the electric resistance welded portion is annealed by heating at 850° C. to 950° C. 2 C0.3% or less, Si 1.0% or less in weight percentage,
Mn0.2-1.2%, P0.04% or less, S0.01
% or less and 0.01 to 0.10% of Al, and 0.005 to 0.1% of at least one kind of lanthanide element, which is a rare earth element, and 0.05 to 0.5% of Cu.
steel strips containing Fe, with the remainder essentially consisting of Fe, are joined by seam welding to form a pipe, and then this electric resistance welded portion is heated at 850°C to 90°C.
A method for manufacturing an electric resistance welded steel pipe having an electric resistance welded portion with excellent groove corrosion resistance, characterized by heating and annealing at 50°C.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1476177A JPS6037173B2 (en) | 1977-02-14 | 1977-02-14 | Method for manufacturing an electric resistance welded steel pipe having an electric resistance welded part with excellent groove corrosion resistance |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1476177A JPS6037173B2 (en) | 1977-02-14 | 1977-02-14 | Method for manufacturing an electric resistance welded steel pipe having an electric resistance welded part with excellent groove corrosion resistance |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS53100158A JPS53100158A (en) | 1978-09-01 |
JPS6037173B2 true JPS6037173B2 (en) | 1985-08-24 |
Family
ID=11870053
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1476177A Expired JPS6037173B2 (en) | 1977-02-14 | 1977-02-14 | Method for manufacturing an electric resistance welded steel pipe having an electric resistance welded part with excellent groove corrosion resistance |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6037173B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2601986Y2 (en) * | 1991-10-31 | 1999-12-13 | 古河電池株式会社 | Plate for lead-acid battery |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0762214B2 (en) * | 1989-10-12 | 1995-07-05 | 新日本製鐵株式会社 | Electric resistance welded steel pipe having high resistance to selective corrosion of the electric resistance welded part and method for manufacturing the same |
-
1977
- 1977-02-14 JP JP1476177A patent/JPS6037173B2/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2601986Y2 (en) * | 1991-10-31 | 1999-12-13 | 古河電池株式会社 | Plate for lead-acid battery |
Also Published As
Publication number | Publication date |
---|---|
JPS53100158A (en) | 1978-09-01 |
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