JP4415544B2 - Metal dusting metal material with excellent high temperature strength - Google Patents

Description

【表２】

【表３】

【表４】

このようにして得た各金属材料の試験片を用いて、体積比で２６％Ｈ₂−６０％ＣＯ−１１．５％ＣＯ₂−２５％Ｈ₂Ｏの雰囲気中で、６５０℃にて１０００時間保持する試験を行った。
【０１０４】
次いで、試験片の表面堆積物を除去し、超音波洗浄を施した後、深度測定器によって最大の減肉深さを測定し、耐メタルダスティング性を評価した。
【０１０５】
又、固溶化熱処理を施した厚さ２０ｍｍの板材から、厚さ２ｍｍの板状引張試験片を作製し、６５０℃で引張試験を行って引張強度を測定することも行った。
【０１０６】
上記の各調査結果を表５にまとめて示す。
【０１０７】
【表５】

表５から、化学組成が本発明で規定する条件を満たす試験番号１〜７、１１〜１９、２１〜２６の金属材料は、最大減肉深さが極めて小さく耐メタルダスティング性に優れ、更に、６５０℃での引張強度も大きく高温強度にも優れていることが明らかである。
【０１０８】
これに対し、化学組成が本発明で規定する条件から外れた金属材料のうち、試験番号２７の金属材料は耐メタルダスティング性と高温強度のいずれにも劣っており、試験番号２８及び２９の金属材料は耐メタルダスティング性に劣っている。
【０１０９】
【発明の効果】
本発明の金属材料は、耐メタルダスティング性及び高温強度に優れているので、石油精製や石油化学プラントなどにおける加熱炉管、配管、或いは熱交換器管などに利用することができ、装置の耐久性や安全性を大幅に向上させることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention is a high Cr used in containers, reaction tubes, parts, etc. exposed to high-temperature atmospheres in heat exchange type hydrocarbon reforming equipment and waste heat recovery equipment in petroleum refining and petrochemical plants. -It relates to the metal material which is a high Ni-Fe system alloy, a multilayer metal material, and the metal tube which uses them as a raw material.
[0002]
[Prior art]
Gases for clean energy fuels such as hydrogen and methanol are expected to greatly increase demand in the future. To that end, hydrocarbon reformers are becoming larger and more highly efficient and suitable for mass production. In addition, conventional hydrocarbon reformers in petroleum refining and petrochemical plants, ammonia production equipment using petroleum as a raw material, hydrogen production equipment, etc. also use heat for waste heat recovery to increase energy efficiency. Exchange is becoming increasingly used.
[0003]
In order to effectively utilize the heat of such a high-temperature gas, heat exchange in a temperature range of 400 to 700 ° C., which is lower than that conventionally targeted, is important. In this temperature range, a reaction tube, a heat exchanger, etc. Corrosion associated with the carburization phenomenon of high Cr—high Ni—Fe alloy-based metallic materials used in the present invention is a problem.
[0004]
Usually, the reaction gas, ie H₂ , CO, CO₂ , H₂A gas containing a hydrocarbon such as O 2 and methane and a metal material such as a reaction tube are in contact with each other at a high temperature around 1000 ° C. or higher. In this temperature range, elements having a higher oxidation tendency than Fe and Ni are selectively oxidized on the surface of the metal material, and corrosion is suppressed by forming a dense oxide film such as Cr oxide and Si oxide. However, in relatively low temperature parts such as heat exchange parts, the diffusion of elements from the metal material to the surface is insufficient and the formation of an oxide film with a corrosion-inhibiting effect is delayed. It is adsorbed on the surface of the material, C enters the metal material and carburization occurs.
[0005]
When carburization proceeds in such an environment and a carburized layer containing carbides such as Cr and Fe is formed, the volume of the portion expands, and as a result, fine cracks are likely to occur. Further, when C penetrates into the metal material and the formation of carbide is saturated, the metal powder generated by the decomposition of the carbide is peeled off from the surface of the metal material, and corrosion consumption called metal dusting proceeds. Further, the peeled metal powder becomes a catalyst, and carbon deposition on the surface of the metal material is promoted. When such blockage due to wear or carbon deposition increases, there is a risk of operation interruption due to equipment failure or the like, so that sufficient consideration must be given to the selection of materials as equipment members.
[0006]
Conventionally, various countermeasures have been studied for metal dusting. For example, in Patent Document 1, H₂ , CO, CO₂ , H₂Since the Fe-based alloy or Ni-based alloy containing 11 to 60% of Cr (wt%, the same applies hereinafter) is excellent in the resistance to metal dusting in an atmosphere gas of 400 to 700 ° C containing O 2, the Fe-based alloy Nb is added to materials containing 24% or more of Cr and 35% or more of Ni, Ni-based alloys containing 20% or more of Cr and 60% or more of Ni, and Fe-based alloys or Ni-based alloys. An invention of such materials is disclosed. However, in general, a sufficient carburization suppressing effect cannot be obtained only by increasing the Cr or Ni content of the Fe-based alloy or Ni-based alloy, and it is necessary to further suppress metal dusting.
[0007]
The method disclosed in Patent Document 2 is based on the elements 8th, 1B, 4th and 5th groups of the periodic table for corrosion caused by metal dusting of “high temperature alloy” containing iron, nickel and chromium. A technique in which one or more metals and mixtures thereof are attached to a surface by ordinary physical or chemical means and annealed in an inert atmosphere to form a thin layer having a thickness of 0.01 to 10 μm. is there. In particular, it is described that the effect is large in the case of a thin layer of Sn, Pb, Bi or the like. However, even if this method is effective in the initial stage, the effect is lost if the thin layer is peeled off after long-term use.
[0008]
In addition, H in atmosphere gas₂A method of adding S is also considered, but H₂Since S may significantly reduce the activity of the catalyst used for hydrocarbon reforming, its application is limited. As described above, although various studies have been made, no metal material capable of sufficiently suppressing metal dusting has been obtained at present.
[0009]
[Patent Document 1]
JP-A-9-78204
[Patent Document 2]
JP-A-11-172473
[0010]
[Problems to be solved by the invention]
The present invention has been made in view of the above situation, and its purpose is to₂ , CO, CO₂ , H₂In an environment where metal dusting is likely to occur, such as in a gas atmosphere containing O 2 and hydrocarbons, a metallic material that is a high Cr—high Ni—Fe alloy having excellent high temperature strength as well as excellent corrosion resistance. It is to provide a layer metal material and a metal tube made of them.
[0011]
[Means for Solving the Problems]
The gist of the present invention is as follows: (1) to (7), a metal dusting-resistant metal material excellent in high-temperature strength, a multilayer metal material shown in (8), a metal tube shown in (9), and (10) In the multilayer metal tube shown.
[0012]
  (1) By mass%, C: more than 0.2% to 0.6%, Si: 0.01-4%, Mn: 0.01-2%, P: 0.03% or less, S: 0.01% or less, Cr: 18 to 35%, Ni: 40 to 78%, Al: 0.005% or more4%N: 0.001 to 0.2%, Cu: 0.13 to 5.5% and Co: 0.015 to 5.5%, either one or two, and the balance is Fe And a metal dusting-resistant metal material excellent in high-temperature strength, wherein the value of fn1 represented by the following formula (1) is 50 or more.
[0013]
  fn1 = 40Si + Ni + 5Al + 40N + 10 (Cu + Co)...(1).
here,(1)The element symbol in the formula represents the content of the element in mass%.
[0014]
  (2) By mass%, C: more than 0.2% up to 0.6%, Si: 0.01-4%, Mn: 0.01-2%, P: 0.03% or less, S: 0.01% or less, Cr: 18 to 35%, Ni: 40 to 78%, Al: 0.005% or more4%N: 0.001 to 0.2%, Cu: 0.13 to 5.5% and Co: 0.015 to 5.5%, or any one or two of them, and further below The high temperature strength is characterized in that it contains at least one of the components of the group (a) shown, the balance is Fe and impurities, and the value of fn1 expressed by the following formula (1) is 50 or more. Excellent metal dusting metal material.
[0015]
(A) Mo: 0.05 to 10%, Ta: 0.05 to 5%, W: 0.05 to 5%, Ti: 0.01 to 1.4%, V: 0.01 to 1%, Zr: 0.01-2.5%, Nb: 0.01-2.5% and Hf: 0.01-1%.
[0016]
  (3) By mass%, C: more than 0.2% to 0.6%, Si: 0.01-4%, Mn: 0.01-2%, P: 0.03% or less, S: 0.01% or less, Cr: 18 to 35%, Ni: 40 to 78%, Al: 0.005% or more4%N: 0.001 to 0.2%, Cu: 0.13 to 5.5% and Co: 0.015 to 5.5%, or any one or two of them, and further below It contains at least one of the components of the group shown in (a), the balance is made of Fe and impurities, the value of fn1 expressed by the following formula (1) is 50 or more, and expressed by the following formula (2) An anti-metal dusting metal material excellent in high-temperature strength, wherein the value of fn2 is 0.003 or more.
[0017]
  fn2 = (Mo / 192) + (Ta / 181) + (W / 368) + (Ti / 48) + (V / 51) + (Zr / 92) + (Nb / 93) + (Hf / 179). ...(2).
Here, the element symbol in each formula represents the content in mass% of the element.
[0018]
(4) In place of a part of Fe, the high-temperature strength according to any one of (1) to (3) above containing at least one of the components of the group (b) shown below was excellent. Metal dusting resistant metal material.
[0019]
(B) B: 0.0005 to 0.02%, Ca: 0.0005 to 0.02%, and Mg: 0.0005 to 0.02%.
[0020]
(5) In place of a part of Fe, the high-temperature strength according to any one of (1) to (4) above containing at least one of the components of the group (c) shown below was excellent. Metal dusting resistant metal material.
[0021]
(C) La: 0.005-0.3%, Ce: 0.005-0.3%, Nd: 0.005-0.3% and Y: 0.005-0.3%.
[0022]
  (6) Fe content10% Of the above-mentioned (1) to (5), the metal dusting-resistant metal material having excellent high-temperature strength.
[0023]
(7) Hydrocarbon, CO and H₂ The sum of the contents of is for a member used in an atmosphere having a total of 25 vol% or more, a total of hydrocarbon and CO of 1 vol% or more, and 1000 ° C or less, according to any one of (1) to (6) above Metal dusting metal material with excellent high temperature strength.
[0024]
  (8) The surface of the surface in contact with an atmosphere in which at least metal dusting occurs, including at least one metal dusting-resistant metal material layer having excellent high-temperature strength as described in any of (1) to (6) aboveLayerA multilayer metal material characterized by being a layer of the above-described metal dusting metal material excellent in high temperature strength.
[0025]
(9) A metal tube which is a metal dusting-resistant metal material excellent in high-temperature strength according to any one of (1) to (6) above.
[0026]
  (10) The material is a multilayer metal material according to (8) above,Table in contact with the atmosphere where metal dusting occursMulti-layer metal tube whose surface is a layer of metal dusting metal material with excellent high-temperature strength.
[0027]
Hereinafter, the inventions related to (1) to (10) of the metal dusting-resistant metal material, the multilayer metal material, the metal material tube, or the multilayer metal tube are referred to as the inventions of (1) to (10), respectively.
[0028]
The present inventors have conducted various studies on metal materials having excellent resistance against a corrosion phenomenon called metal dusting that occurs at a temperature of 1000 ° C. or lower.
[0029]
The occurrence of metal dusting is affected by the protection of the oxide film formed on the surface and the development of the carburized layer formed inside. In other words, when the oxide film is cracked or peeled off, C penetrates into the metal and a carburized layer is formed, and metal dusting is considered to occur due to volume change or carbide formation decomposition at that time. . Then, while improving the protective property of an oxide film, it examined about the composition of the metal material for suppressing the growth of a carburized layer.
[0030]
In order to increase the protective property of the oxide film, it is most effective to increase the Cr content, and it is preferable to contain an element having a strong affinity for oxygen such as Si or Al. This is the same as a general method for improving oxidation resistance.
[0031]
By the above measures, the intrusion of C into the metal material is considerably suppressed, but the intrusion of C is completely blocked, in other words, the oxide film does not crack at all and does not peel off for a long time. It is impossible to realize that. Therefore, as in the case of blocking the entry of C by the oxide film, it is indispensable to suppress the growth of the carburized layer in order to improve the metal dusting resistance.
[0032]
Therefore, the effect of various element additions on the growth of the carburized layer was investigated on the basis of an alloy composed of approximately 25% Cr, Ni approximately 60%, and the balance mainly composed of Fe as a high temperature material. As a result, one element, such as Si, Al, Ni, which seems to have little affinity with carbon, and the other element, which forms stable carbides in metal materials such as Ti, Nb, V, Mo, etc. It became clear that it has the effect of suppressing the growth rate of the carburized layer.
[0033]
  The carburized layer is, for example, on the metal surface depending on the atmospheric conditions,
        C + CO₂= 2CO ...(3)
Such a reaction proceeds from the right side to the left side, and the generated C is adsorbed on the surface of the metal material and penetrates into the metal material.
[0034]
When carbide-forming elements are present, it is considered that the invaded C bonds with these elements, thereby suppressing the diffusion of C and suppressing the growth of the carburized layer. However, the reason why Si, Al, Ni, etc. suppress the growth of the carburized layer is not necessarily clear.
[0035]
Upon further investigation, other elements that suppress the growth of the carburized layer were found, although they were not other carbide-forming elements. Therefore, when these elements were examined for interaction with C from the viewpoint of solute elements in Fe, all of them were elements in which the interaction assistant coefficient Ω showed a positive value.
[0036]
If Ω is positive, there is an effect of increasing the activity of C, which is a solute element, and if the activity of C in the metal material is increased, the amount of solute C is reduced and the flux to the inside is reduced. It seems that growth will slow down.
[0037]
When an element having positive Ω is examined, for example, P and S show a large positive Ω value, but the properties such as hot workability and toughness of the metal material are deteriorated, so the content must be reduced. . Similarly, regarding Ag and As having a high Ω value, it is difficult to use both Ag for cost and As for toxicity.
[0038]
Among the elements with positive Ω, Co and Cu are usually used as additive elements in steel, and as a result of investigating the effect of the addition, it is effective for improving metal dusting resistance. There was found. Further, although it is difficult to contain a large amount, it has been clarified that N can also be used for improving metal dusting resistance.
[0039]
For each element of Si, Al, Ni, Co, Cu, and N, the relationship between the content and the growth inhibition effect of the carburized layer is investigated using a test molten metal, and the obtained result is subjected to multiple regression calculation. Thus, the effect of the content of each element on the effect of suppressing the growth of the carburized layer and, therefore, the metal dusting resistance could be clarified.
[0040]
Next, elements that form stable carbides in metal materials such as Ti, Nb, V, and Mo also have an action of suppressing the growth of the carburized layer, so the influence of their contents was examined. As a result, the effect of suppressing the growth of the carburized layer by the element that forms a stable carbide in the metal material is almost proportional to the atomic concentration, and the contents of Mo and W are 1/2 of the atomic concentration, other elements It has been found that if the total concentration is an index as the atomic concentration, the above effect can be quantitatively shown by the index. This indicates that these elements suppress the growth of the carburized layer by combining with the carbon that has entered from the surface to form a stable carbide as described above.
[0041]
In this way, the entry of C into the metal material by containing an element that strengthens the oxide film formed on the surface, the inclusion of an element having a positive interaction assistant coefficient Ω, and this In addition, it has been found that the metal dusting resistance of the high Cr-high Ni-Fe alloy can be greatly improved by further suppressing the growth of the carburized layer in a carburizing atmosphere by simultaneously containing an appropriate amount of a carbide forming element.
[0042]
However, the addition of the above various elements may adversely affect hot workability and high temperature corrosion resistance depending on the content. In order to prevent such an adverse effect, it is effective to contain the following elements.
[0043]
That is, when a small amount of B, Ca, and Mg is contained, cracks during hot working of the target metal material are suppressed, and hot workability is improved. These elements are thought to bring about an effect of improving hot workability by strengthening the grain boundaries of steel and changing the form of trace inclusions.
[0044]
When a small amount of rare earth elements such as La, Ce, Nd and Y are contained, the corrosion resistance and oxidation resistance at high temperatures are improved. This is considered to be due to the fact that the above elements promote the uniform formation of Cr, Al, and Si oxide films and increase the adhesion between the oxide film and the metal material interface.
[0045]
In addition, the metal dusting resistance is greatly enhanced by the two actions of the action of enhancing the protective property of the oxide film formed on the surface and the action of suppressing the growth of the carburized layer due to the positive interaction assistant coefficient Ω. When a large amount of Si and Al is contained, the hot workability and weldability are significantly reduced.
[0046]
However, as a result of the study by the present inventors, the reduction in hot workability and weldability due to containing a large amount of Si and Al can be improved if the contents of P, S and N in the metal material are simultaneously reduced. Became clear.
[0047]
That is, in the case of a metal material that is inferior in hot workability and weldability, the bond between the grain boundaries is weak, and if the grain interior is strengthened, there is a relative difference between the grain grain strength and the grain boundary strength. Since it becomes large, cracks originating from the grain boundary frequently occur during hot working or welding. For this reason, limiting P and S which segregate at the grain boundaries and weaken the bonding force, and at the same time, limit N which precipitates nitrides within the grains, suppresses grain boundary cracking during hot working or welding. It is effective for.
[0048]
P, S, and N are elements that increase the interaction coefficient Ω and improve the metal dusting resistance. However, the metal dusting resistance can be greatly improved by containing a large amount of Si and Al rather than containing P, S and N. Therefore, when high metal dusting resistance is required, Si and Al are contained in a large amount, and the hot workability and weldability are thereby reduced, and the contents of P, S and N are limited. It is good to suppress with.
[0049]
When the metal material is used at a high temperature, the life can be extended as the strength at the high temperature increases. On the other hand, if the lifespan is approximately the same, the greater the strength at high temperature, the thinner the design thickness of the member, so the cost can be reduced.
[0050]
Therefore, the means for increasing the strength at high temperature was also examined. As a result, by adding C in a mass% exceeding 0.2% and positively containing an element having a positive interaction assistant coefficient Ω, the activity of C can be increased to increase the activity of C. It was found that if the amount of C dissolved in the solid solution is reduced, carbides precipitate at the grain boundaries and within the grains, and a significant improvement in high-temperature strength can be achieved.
[0051]
The inventions (1) to (10) have been completed based on the above findings.
[0052]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the reason for limiting the composition of the metal dusting metal material is as follows. In the following description, “%” display of the content of each element means “mass%”.
[0053]
  Cr:
  Cr is a basic component of a metal dusting metal material according to the present invention intended for use at high temperatures. Cr has an action of delaying the growth of the carburized layer by combining with C that has penetrated into the metal material in a high-temperature use environment, thereby ensuring good metal dusting resistance. This effect is due to the Cr content18% Or better. However, if its content exceeds 35%, the toughness is lowered and the hot workability is deteriorated, making it difficult to produce. Therefore, the Cr content18To 35%. In addition, the preferable content of Cr is 18 to 33%, and 25.2 to 33% is extremely preferable.
[0054]
Ni:
Ni is a basic component of the metal dusting-resistant metal material according to the present invention, and maintains the high temperature strength and the structural stability, and has the effect of increasing the corrosion resistance by coexisting with Cr. Ni also has an effect of suppressing the occurrence of metal dusting. These effects are remarkably exhibited when the Ni content is 40% or more, and the effect becomes more remarkable as the content increases up to 78%. Therefore, the content of Ni is set to 40 to 78%. The Ni content is preferably 48 to 78%, and more preferably 50 to 78%. It is very preferable if the Ni content is 56 to 78%.
[0055]
C:
C has the effect | action which raises the intensity | strength of a metal material, and a big high temperature intensity | strength is securable by making it contain exceeding 0.2%. However, when the content exceeds 0.6%, the toughness of the metal material is lowered. Furthermore, due to the extreme decrease in ductility, the high temperature strength is decreased. Therefore, the C content is set to more than 0.2% and up to 0.6%. The C content is preferably 0.22 to 0.55%, more preferably 0.25 to 0.5.
[0056]
Si:
Si has a deoxidizing action when the metal material is melted. Si forms a Si oxide film under the Cr oxide film on the surface of the metal material, suppresses the intrusion of C into the metal, and increases the activity of C in the metal material, greatly improving the metal dusting resistance. It also has the effect of improving. In order to obtain these effects, the Si content needs to be 0.01% or more. However, the addition of a large amount of Si causes a decrease in hot workability and weldability. In particular, when its content exceeds 4%, the hot workability and weldability deteriorate significantly. Therefore, the lower limit of the Si content is set to 0.01%, and the upper limit is set to 4%. The lower limit and upper limit of the Si content are more preferably 0.05% and 3.5%, respectively, and more preferably 0.1% and 3.2%.
[0057]
In addition, when the N content described later exceeds 0.055%, the upper limit of the Si content is 2% from the viewpoint of weldability and hot workability, and the upper limit of the Al content is also 2 % Is good.
[0058]
In the case where the upper limit of the N content described later is 0.055%, good hot workability and weldability can be secured. In this case, in order to greatly improve the metal dusting resistance, The content may be 1.1% or more. In this case, in order to obtain better hot workability and weldability, the upper limit of the Al content is more preferably 0.5%.
[0059]
Mn:
Mn has an action of suppressing hot work brittleness due to S contained as an impurity and a deoxidation action at the time of melting. In order to obtain such effects, Mn is contained at least 0.01% or more. However, Mn promotes the penetration of C from the atmosphere and reduces the activity of C in the metal material and inhibits the formation of Cr or Al oxide film on the surface of the metal material to generate metal dusting. Since it is an element that makes it easy to cause it to be contained, its content must be at most 2%. The Mn content is more preferably 0.05 to 1.0%, and even more preferably 0.1 to 0.8%.
[0060]
P:
P is an impurity element mixed from the raw material when the metal material is melted. Since corrosion resistance is lowered and hot workability and weldability are deteriorated, it is desirable to reduce as much as possible. Therefore, the content is made 0.03% or less. The P content is more preferably 0.025% or less, and extremely preferably 0.02% or less.
[0061]
S:
S is also an impurity element mixed from the raw material when the metal material is melted. Since corrosion resistance is lowered and hot workability and weldability are deteriorated, it is desirable to reduce as much as possible. Therefore, the content is made 0.01% or less. The S content is more preferably 0.007% or less, and very preferably 0.002% or less.
[0062]
  Al:
  Al has a deoxidizing action when the metal material is melted. For Al, by forming an Al oxide film below the Cr oxide film on the surface of the metal material, or by forming an Al oxide film on the outermost surface of the metal material, the penetration of C into the metal material is suppressed. It also has the effect of increasing the activity of C in the metal material and greatly improving the resistance to metal dusting. In order to obtain these effects, the Al content needs to be 0.005% or more. However, the addition of a large amount of Al causes a decrease in hot workability and weldability. Especially its content4%If it becomes above, the fall of hot workability and weldability will become remarkable. Therefore, the lower limit of the Al content is 0.005% and the upper limit is4%Less than. Al contentUnderMore preferably, the limit is 0.01% and the upper limit is less than 3.7%.
[0063]
In addition, when the N content described later exceeds 0.055%, the upper limit of the Al content is 2% from the viewpoint of weldability and hot workability, and the upper limit of the Si content is also 2 % Is good.
[0064]
When the upper limit of the N content described later is 0.055%, good hot workability and weldability can be ensured. In this case, in order to greatly improve the metal dusting resistance, Al The content may be 2.6% or more. In this case, in order to obtain better hot workability and weldability, the upper limit of the Si content is more preferably 0.5%.
[0065]
N:
N has an action of increasing the activity of C in the metal material and improving the resistance to metal dusting. However, if the content is less than 0.001%, the above effect cannot be obtained sufficiently. On the other hand, if the N content exceeds 0.2%, a large amount of Cr or Al nitride is formed, and the hot workability and weldability are significantly reduced. Therefore, the lower limit of N content is 0.001% and the upper limit is 0.2%.
[0066]
When the upper limit of the Si and Al contents is 2%, the lower limit of the N content is preferably 0.005%. In this case, the upper limit of the N content is more preferably 0.15%.
[0067]
  On the other hand, in order to greatly enhance the resistance to metal dusting, the content of Si and Al is set to 1.1% or more and 2.6% or more, respectively, and Si is contained up to 4%. For quantity and Al4%When the content is less than the upper limit, the upper limit of the N content is preferably 0.055% from the viewpoints of weldability and hot workability. In this case, the upper limit of the N content is more preferably 0.035%, and extremely preferably 0.025%.
[0068]
  Cu and Co:
  Cu and Co are important elements in the present invention. All of these elements increase the activity of C in the metal material, and as a result, suppress the growth of the carburized layer and improve the metal dusting resistance. The effect is CuContaining 0.13% or moreCo0.015% Or more. However, if both Cu and Co are contained in excess of 5.5%, the hardness of the metal material is increased and the productivity is lowered. Therefore, CuContent of 0.13 to 5.5%,Co content0.015˜5.5%. CuThe preferred content of is 0.13 to 4.8%, more preferred is 0.13 to 4.2%, andThe preferable content is 0.02 to 4.8%, and more preferably 0.05 to 4.2%. In addition, Cu and Co may contain any 1 type and may contain both.
[0069]
fn1:
As already described, the present inventors have investigated the relationship between the content of each element of Si, Al, Ni, Co, Cu, and N that increases the activity of C in the metal material and the effect of suppressing the growth of the carburized layer. Were investigated using test melts.
[0070]
  As a result, the effect of the content of each element on the effect of suppressing the growth of the carburized layer, and thus on the metal dusting resistance(1)It became clear that it can be arranged by the value of fn1 expressed by the equation. The larger the value of fn1, the greater the metal dusting resistance, that is, the effect of suppressing the occurrence of metal dusting. When the value of fn1 is 50 or more, good metal dusting resistance can be ensured. Therefore, the(1)The value of fn1 represented by the formula was defined as 50 or more. In order to obtain a more remarkable effect, the value of fn1 is preferably 60 or more. The value of fn1 is more preferably 70 or more, and more preferably 80 or more.
[0071]
  Note that when the Si content is 1.1 to 4% and the value of fn1 is 95 or more, or the Al content is 2.6% or more.4%If the value is less than 70 and the value of fn1 is 70 or more, extremely good metal dusting resistance can be obtained. When the Si content is 1.1 to 4% and the value of fn1 is 110 or more, or the Al content is 2.6% or more4%If the value is less than 90 and the value of fn1 is 90 or more, better metal dusting resistance can be obtained.
[0072]
The component elements other than Fe contained in the metal dusting metal material according to the invention of (1) may be only the above elements from Cr to N, and any one or more elements of Cu and Co. Good. However, in addition to the above components, one or more elements of the groups (a) to (c) can be selectively contained as necessary. That is, one or more elements of the groups (a) to (c) may be added and added as optional additional elements.
[0073]
Hereinafter, the above optional additive elements will be described.
[0074]
Mo, Ta, W, Ti, V, Zr, Nb and Hf: (a) group
Any of these elements is a carbide forming element, and if added, has the effect of suppressing the growth of the carburized layer and enhancing the resistance to metal dusting. Each of the above elements also has the effect of increasing the high temperature strength.
[0075]
In order to reliably obtain the above effects, it is preferable that Mo, Ta, and W each have a content of 0.05% or more, and Ti, V, Zr, Nb, and Hf all have a content of 0.01% or more. The content is preferable. However, Mo exceeds 10%, Ta and W exceed 5%, Ti exceeds 1.4%, Zr and Nb exceed 2.5%, and V and Hf exceed 1%. If they are contained, the hot workability, toughness, and weldability are reduced.
[0076]
Therefore, when adding Mo, Ta, W, Ti, V, Zr, Nb and Hf, the respective contents are 0.05 to 10% for Mo, 0.05 to 5% for Ta, and 0. 05-5%, Ti 0.01-1.4%, V 0.01-1%, Zr 0.01-2.5%, Nb 0.01-2.5% and Hf 0 .01 to 1% is preferable. The range of preferable content in the case of adding is as follows: Mo is 1 to 10%, Ta and W are both 0.5 to 5%, Ti is 0.01 to 0.8%, and Zr and Nb are both 0.00. 01 to 2.0%, V and Hf are both 0.01 to 0.6%. The range of more preferable content when added is 1 to 8% for Mo, 1 to 3% for Ta and W, 0.01 to 0.4% for Ti, and 0.02 for both Zr and Nb. -1.6%, V is 0.01-0.3%, and Hf is 0.02-0.6%.
[0077]
The above-mentioned Mo, Ta, W, Ti, V, Zr, Nb, and Hf can be added alone or in combination of two or more.
[0078]
The anti-metal dusting metal material according to the invention of (1) contains only one of Mo, Ta, W, Ti, V, Zr, Nb and Hf, or a combination of two or more. Thus, the metal dust-proof metal material according to the invention of (2) is obtained.
[0079]
fn2:
As already described, the present inventors examined the relationship between the content of elements that form stable carbides in metal materials and the effect of suppressing the growth of the carburized layer.
[0080]
  As a result, the effect of Mo, Ta, W, Ti, V, Zr, Nb, and Hf, which produce stable carbides in the metal material, suppresses the growth of the carburized layer is almost proportional to the atomic concentration, and the content is Mo. And W is ½ of the atomic concentration, other elements are atomic concentrations, and if the total concentration is taken as an index, that index, that is,(2)It has been clarified that the effect of suppressing the growth of the carburized layer, and hence the resistance to metal dusting, can be arranged by the value of fn2 expressed by the equation.
[0081]
  The larger the value of fn2, the greater the resistance to metal dusting, that is, the effect of suppressing the occurrence of metal dusting. Particularly when the value of fn2 is 0.003 or more, good metal dusting resistance can be secured. . Therefore, the(2)The value of fn2 represented by the formula is preferably 0.003 or more. The value of fn2 is more preferably 0.005 or more, and even more preferably 0.007 or more.
[0082]
In the metal dusting-resistant metal material according to the invention of (2), only one of Mo, Ta, W, Ti, V, Zr, Nb and Hf so that the value of fn2 is 0.003 or more, Alternatively, the metal dusting metal material according to the invention of (3) can be obtained by compounding two or more kinds.
[0083]
B, Ca and Mg: (b) group
Any of these elements, when added, has the effect of improving hot workability. In order to surely obtain this effect, it is preferable that the content is 0.0005% or more. However, if the B content exceeds 0.02%, the metal material becomes embrittled and the melting point is lowered, resulting in a decrease in hot workability and weldability. Further, when both Ca and Mg contents exceed 0.02%, they become oxide inclusions, leading to deterioration of product surface quality and deterioration of corrosion resistance. Therefore, the contents when adding B, Ca and Mg are all preferably 0.0005 to 0.02%. The preferable range of the content of any element is 0.0005 to 0.015%, and the more preferable range is 0.0005 to 0.012%. In addition, these elements can be added only in any 1 type or 2 or more types of composite.
[0084]
By containing only one of the above-mentioned B, Ca and Mg, or a combination of two or more thereof in the metal dust-resistant metal material according to the invention of (1) to (3), (4) A metal dusting metal material according to the invention is obtained.
[0085]
La, Ce, Nd and Y: (c) group
Any of these elements, when added, has the effect of improving the adhesion and improving the corrosion resistance by improving the uniformity of the oxide film containing Cr and Al generated on the surface of the metal material in the use environment. In order to reliably obtain this effect, it is preferable that the content is 0.005% or more. However, if the content of any element exceeds 0.3%, a coarse oxide is formed, leading to a decrease in toughness and hot workability, and the occurrence of surface defects is increased. Therefore, the contents when adding La, Ce, Nd and Y are all preferably 0.005 to 0.3%. The preferable range of the content of any element is 0.005 to 0.1%, and the more preferable range is 0.005 to 0.07%. In addition, these elements can be added only in any 1 type or 2 or more types of composite.
[0086]
By including only one of La, Ce, Nd and Y, or a combination of two or more in the metal dust-proof metal material according to the inventions (1) to (4), (5 The metal dusting metal material according to the invention is obtained.
[0087]
  Fe:
  Fe is a substantial balance element for the metal dusting metal material according to the present invention. However, Fe lowers the density of the oxide film of Cr, Al and Si generated on the surface of the metal material. If the oxide film formed on the surface of the metal material is dense and has excellent adhesion to the metal material, the effect of blocking the penetration of C into the metal material is greater. In this case, good metal dusting resistance Sex is obtained. Therefore, it is better to reduce the Fe content, which reduces the density of the oxide film.Yes. ThisIn this case, if the Fe content is 10% or less, the adverse effect of the oxide film on the intrusion blocking effect of C into the metal material is small, so the Fe content should be reduced to 10% or less. Is good. A more preferable upper limit of the Fe content is 9%, and a more preferable upper limit is 8%.
[0088]
By limiting the content of Fe contained as a substantial balance element in the metal-resistant metal dusting metal material according to the inventions of (1) to (5), the metal dust-resistant metal material according to the invention of (6) is obtained. can get.
[0089]
In the metal dusting metal material according to the inventions (1) to (6), the Si content is 1.1 to 4% and the value of fn1 is 95 or more, so that the metal resistance is further improved. Dusting property can be obtained. Furthermore, in addition to the above-described definition of the Si content and the value of fn1, if the Al content is 0.005 to 0.5%, even better hot workability and weldability can be obtained. .
[0090]
  Further, in the metal dust-proof metal material according to the inventions (1) to (6), the Al content is 2.6% or more.4%When the value is less than 70 and the value of fn1 is 70 or more, better metal dusting resistance can be obtained. Furthermore, if the Si content is 0.01 to 0.5% in addition to the above-mentioned definition of the Al content and the value of fn1, even better hot workability and weldability can be obtained. .
[0091]
In each of the above cases, if the Fe content is further reduced to 10% or less, extremely good metal dusting resistance can be obtained.
[0092]
Metal dust-resistant metal materials according to the inventions (1) to (6) are particularly hydrocarbons, CO and H₂ Is excellent in metal dusting resistance in an atmosphere having a total content of 25 vol% or more, a total of hydrocarbon and CO of 1 vol% or more and 1000 ° C. or less. Therefore, if these metal dusting metal materials are applied to members such as reaction tubes and peripheral equipment in heat exchange reformers and waste heat recovery equipment in petrochemical plants, the durability and safety of the equipment will be greatly increased. Can be improved. That is, the metal dusting metal material according to the inventions (1) to (6) is suitable for a member exposed to the environment (the invention of (7)).
[0093]
The metal dusting resistant metal material according to the present invention is produced by a general manufacturing process applied to steel and other metal materials, that is, by means such as melting, casting, hot working, cold working, welding, etc. What is necessary is just to shape | mold to a required shape, such as a non-pipe, a welded tube, a board, and a rod, and you may shape | mold to a required shape by methods, such as powder metallurgy and centrifugal casting.
[0094]
The invention of (9) relates to a “pipe” whose shape after molding.
[0095]
In addition, after shaping | molding, you may give the homogenization process (solution heat treatment) heated, for example to 1050-1250 degreeC. Furthermore, after the molding or the homogenization treatment, the metal material surface may be subjected to a surface processing treatment such as pickling, shot blasting, grinder polishing, and electrolytic polishing.
[0096]
The metal dusting-resistant metal material according to the present invention exhibits excellent resistance in an atmosphere where metal dusting occurs, so it is not only used alone but also as a multilayer metal material having two or more layers. Also good.
[0097]
  When used as a multilayer metal material, the metal dusting-resistant metal material according to the present invention only needs to face the atmosphere where metal dusting occurs, so at least the surface in contact with the atmosphere where metal dusting occursLayerWhat is necessary is just to comprise with the metal dusting metal material which concerns on this invention ((8) invention). In this case, the support member (strength member) may be composed of one or more combinations of carbon steel, stainless steel, Ni-base alloy, Co-base alloy, and the like.
[0098]
The method for producing the multilayer metal material according to the present invention is not particularly limited. For example, after joining by normal pressure welding or welding, hot working or cold working may be performed to form a desired shape.
[0099]
The invention of (10) relates to a “pipe” whose shape after molding.
[0100]
In addition, you may produce the layer of the multilayer metal material which faces the atmosphere where metal dusting generate | occur | produces by surface treatments, such as overlay welding, chemical vapor deposition (CVD), physical vapor deposition (PVD), and plating. If the said surface treatment layer exists in the component range of the metal-dusting metal material which concerns on this invention, the resistance with respect to metal dusting can be improved.
[0101]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to this Example.
[0102]
Metal materials having chemical compositions shown in Tables 1 to 4 were melted using a high-frequency heating vacuum furnace, hot forged by a normal method, and then subjected to a solution heat treatment at 1200 ° C. to produce a plate material having a thickness of 20 mm. . Next, a test piece having a thickness of 4 mm, a width of 10 mm, and a length of 20 mm was cut out from the plate material having a thickness of 20 mm.
[0103]
[Table 1]

[Table 2]

[Table 3]

[Table 4]

  Using the test piece of each metal material thus obtained, the volume ratio is 26% H₂-60% CO-11.5% CO₂-25% H₂In the atmosphere of O, the test which hold | maintains at 650 degreeC for 1000 hours was done.
[0104]
Subsequently, after removing the surface deposit of a test piece and performing ultrasonic cleaning, the maximum thickness reduction thickness was measured with the depth measuring device, and metal dusting resistance was evaluated.
[0105]
In addition, a plate-like tensile test piece having a thickness of 2 mm was prepared from a plate material having a thickness of 20 mm subjected to solution heat treatment, and a tensile test was performed at 650 ° C. to measure the tensile strength.
[0106]
The results of the above investigations are summarized in Table 5.
[0107]
[Table 5]

  From Table 5, the test numbers 1-7, 11 which satisfy | fill the conditions which a chemical composition prescribes | regulates by this invention.19, 21-It is apparent that the metal material No. 26 has a very small maximum thickness reduction and excellent metal dusting resistance, and also has a high tensile strength at 650 ° C. and excellent high-temperature strength.
[0108]
On the other hand, among the metal materials whose chemical compositions deviate from the conditions specified in the present invention, the metal material of test number 27 is inferior in both metal dusting resistance and high temperature strength. Metal materials are inferior in metal dusting resistance.
[0109]
【The invention's effect】
Since the metal material of the present invention is excellent in metal dusting resistance and high-temperature strength, it can be used for heating furnace tubes, piping, heat exchanger tubes, etc. in petroleum refining and petrochemical plants. Durability and safety can be greatly improved.

Claims (10)

In mass%, C: more than 0.2% to 0.6%, Si: 0.01-4%, Mn: 0.01-2%, P: 0.03% or less, S: 0.01 %: Cr: 18-35%, Ni: 40-78%, Al: 0.005% or more and less than 4%, N: 0.001-0.2%, Cu: 0.13-5.5% And Co: Any one or two of 0.015 to 5.5%, the balance being Fe and impurities, and the value of fn1 represented by the following formula (1) being 50 or more Metal dusting metal material with excellent high-temperature strength.
fn1 = 40Si + Ni + 5Al + 40N + 10 (Cu + Co) (1)
Here, the element symbol in the formula (1) represents the content in mass% of the element. In mass%, C: more than 0.2% to 0.6%, Si: 0.01-4%, Mn: 0.01-2%, P: 0.03% or less, S: 0.01 %: Cr: 18-35%, Ni: 40-78%, Al: 0.005% or more and less than 4%, N: 0.001-0.2%, Cu: 0.13-5.5% And Co: Any one or two of 0.015 to 5.5%, and further including at least one of the components of group (a) shown below, with the balance being Fe and impurities A metal dusting-resistant metal material excellent in high-temperature strength, wherein the value of fn1 represented by the following formula (1) is 50 or more.
(A) Mo: 0.05 to 10%, Ta: 0.05 to 5%, W: 0.05 to 5%, Ti: 0.01 to 1.4%, V: 0.01 to 1%, Zr: 0.01-2.5%, Nb: 0.01-2.5% and Hf: 0.01-1%
fn1 = 40Si + Ni + 5Al + 40N + 10 (Cu + Co) (1)
Here, the element symbol in the formula (1) represents the content in mass% of the element. In mass%, C: more than 0.2% to 0.6%, Si: 0.01-4%, Mn: 0.01-2%, P: 0.03% or less, S: 0.01 %: Cr: 18-35%, Ni: 40-78%, Al: 0.005% or more and less than 4%, N: 0.001-0.2%, Cu: 0.13-5.5% And Co: Any one or two of 0.015 to 5.5%, and further including at least one of the components of group (a) shown below, with the balance being Fe and impurities The resistance to metallization with excellent high-temperature strength, wherein the value of fn1 represented by the following formula (1) is 50 or more and the value of fn2 represented by the following formula (2) is 0.003 or more. Sting metal material.
(A) Mo: 0.05 to 10%, Ta: 0.05 to 5%, W: 0.05 to 5%, Ti: 0.01 to 1.4%, V: 0.01 to 1%, Zr: 0.01-2.5%, Nb: 0.01-2.5% and Hf: 0.01-1%
fn1 = 40Si + Ni + 5Al + 40N + 10 (Cu + Co) (1),
fn2 = (Mo / 192) + (Ta / 181) + (W / 368) + (Ti / 48) + (V / 51) + (Zr / 92) + (Nb / 93) + (Hf / 179). ... (2)
Here, the element symbol in each formula represents the content in mass% of the element. It replaces with a part of Fe and contains at least 1 sort (s) of the component of the group of (b) shown below, The high-temperature-strength resistance in any one of Claim 1 to 3 characterized by the above-mentioned. Metal dusting metal material.
(B) B: 0.0005 to 0.02%, Ca: 0.0005 to 0.02% and Mg: 0.0005 to 0.02% The high-temperature strength resistance according to any one of claims 1 to 4, characterized in that it contains at least one member of the group (c) shown below instead of a part of Fe. Metal dusting metal material.
(C) La: 0.005-0.3%, Ce: 0.005-0.3%, Nd: 0.005-0.3% and Y: 0.005-0.3%   The metal dusting metal material having excellent high-temperature strength according to any one of claims 1 to 5, wherein the Fe content is 10% or less. The total content of hydrocarbon, CO, and H ₂ is 25 vol% or more, and the total of hydrocarbon and CO is for a member used in an atmosphere of 1 vol% or more and 1000 ° C or less. To 6. The metal dusting metal material excellent in high-temperature strength according to any one of items 6 to 6. 7. A metal dusting-resistant metal material having one or more layers having excellent high-temperature strength according to any one of claims 1 to 6, wherein at least a surface layer in contact with an atmosphere in which metal dusting occurs is the high-temperature strength. A multilayer metal material characterized by being an excellent metal dusting metal material layer.   A metal tube characterized in that the material is a metal dusting-resistant metal material excellent in high-temperature strength according to any one of claims 1 to 6.   The multilayer metal material according to claim 8, wherein the surface in contact with the atmosphere in which metal dusting occurs is a layer of a metal dusting metal material excellent in high-temperature strength. tube.