JP2021025080A - Austenite-stainless steel casting - Google Patents
Austenite-stainless steel casting Download PDFInfo
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- 238000005266 casting Methods 0.000 title claims abstract description 44
- 229910001220 stainless steel Inorganic materials 0.000 title abstract description 3
- 239000010935 stainless steel Substances 0.000 title abstract description 3
- 238000007664 blowing Methods 0.000 claims abstract description 11
- 229910052797 bismuth Inorganic materials 0.000 claims abstract description 7
- 229910052714 tellurium Inorganic materials 0.000 claims abstract description 7
- 229910052684 Cerium Inorganic materials 0.000 claims abstract description 6
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 6
- 229910052746 lanthanum Inorganic materials 0.000 claims abstract description 6
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 6
- 229910052758 niobium Inorganic materials 0.000 claims abstract description 6
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 6
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 6
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 229910000963 austenitic stainless steel Inorganic materials 0.000 claims description 24
- 238000005260 corrosion Methods 0.000 abstract description 30
- 230000007797 corrosion Effects 0.000 abstract description 30
- 239000000203 mixture Substances 0.000 abstract description 13
- 239000002028 Biomass Substances 0.000 abstract description 12
- 229910052711 selenium Inorganic materials 0.000 abstract description 5
- 239000002131 composite material Substances 0.000 abstract description 3
- 229910052799 carbon Inorganic materials 0.000 abstract description 2
- 229910052804 chromium Inorganic materials 0.000 abstract description 2
- 229910052748 manganese Inorganic materials 0.000 abstract description 2
- 229910052750 molybdenum Inorganic materials 0.000 abstract description 2
- 229910052759 nickel Inorganic materials 0.000 abstract description 2
- 230000000694 effects Effects 0.000 description 20
- 229910000831 Steel Inorganic materials 0.000 description 14
- 239000010959 steel Substances 0.000 description 14
- 230000007423 decrease Effects 0.000 description 13
- 239000004033 plastic Substances 0.000 description 8
- 229920003023 plastic Polymers 0.000 description 8
- 229910045601 alloy Inorganic materials 0.000 description 7
- 239000000956 alloy Substances 0.000 description 7
- 230000003647 oxidation Effects 0.000 description 7
- 238000007254 oxidation reaction Methods 0.000 description 7
- 239000000460 chlorine Substances 0.000 description 6
- 239000011159 matrix material Substances 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000004576 sand Substances 0.000 description 5
- 229910052717 sulfur Inorganic materials 0.000 description 5
- 239000002699 waste material Substances 0.000 description 5
- 229910001018 Cast iron Inorganic materials 0.000 description 4
- 229910052801 chlorine Inorganic materials 0.000 description 4
- 238000005242 forging Methods 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 229920006395 saturated elastomer Polymers 0.000 description 4
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- 150000001247 metal acetylides Chemical class 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000005204 segregation Methods 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical class [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 229910001208 Crucible steel Inorganic materials 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 229940069428 antacid Drugs 0.000 description 2
- 239000003159 antacid agent Substances 0.000 description 2
- 230000001458 anti-acid effect Effects 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 2
- 239000000567 combustion gas Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000005553 drilling Methods 0.000 description 2
- 239000002803 fossil fuel Substances 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 238000005987 sulfurization reaction Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 239000002918 waste heat Substances 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 229910017060 Fe Cr Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 239000010730 cutting oil Substances 0.000 description 1
- 230000003009 desulfurizing effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000010920 waste tyre Substances 0.000 description 1
Abstract
Description
本発明はオーステナイト・ステンレス鋼鋳物に関し、特に耐高温腐食に優れたオーステナイト・ステンレス鋼鋳物に関する。 The present invention relates to austenitic stainless steel castings, and particularly to austenitic stainless steel castings having excellent high temperature corrosion resistance.
近年、化石燃料の使用削減の試みとして、バイオマス資源の活用が検討されている。 バイオマス資源は、無駄に廃棄されている資源の再活用の意味もあり、これを燃焼に活用することが化石燃料の使用削減に結びつき注目されている。 In recent years, the utilization of biomass resources has been studied as an attempt to reduce the use of fossil fuels. Biomass resources also have the meaning of reusing resources that are wasted, and the use of these resources for combustion is drawing attention as it leads to a reduction in the use of fossil fuels.
バイオマスボイラとしては、砂等の不活性無機物を熱媒体となるベッド材として火炉に充填し、炉床から空気吹き出しノズルを通して燃焼ガスを吹き込んでベッド材を攪拌し、このベッド材を所望温度に保持しつつ、処理対象物を燃焼できる形式であり、広く普及している。 As a biomass boiler, an inert inorganic substance such as sand is filled in a fireplace as a bed material as a heat medium, and combustion gas is blown from the hearth through an air blowing nozzle to stir the bed material and keep the bed material at a desired temperature. However, it is a format that can burn the object to be processed, and is widely used.
近年では、様々なバイオマス資源を燃料としていることから、Ｈ２Ｏ、ＣＯ２、及びＯ２による酸化の他，プラスチック類の燃料から発生する塩素による塩化および廃タイヤから発生する二酸化硫黄による腐食が問題となっている。腐食は、侵食したＣｌ、Ｓ、Ｏが空気吹き出しノズルのマトリックスに腐食層を生成して蒸発あるいは剥離する現象である。 In recent years, a variety of biomass resources because it is the fuel, H 2 O, CO 2, and other oxidation by O 2, corrosion due to sulfur dioxide generated from chloride and the waste tires by chlorine generated from the fuel plastics It is a problem. Corrosion is a phenomenon in which eroded Cl, S, and O form a corrosive layer in the matrix of the air blowing nozzle and evaporate or peel off.
特許文献1には、ごみ廃却廃熱ボイラ管用鋼高合金鋼が開示されており、耐応力腐食割れ性および耐粒界腐食に優れた溶融塩を生成するごみ焼却炉の廃熱ボイラ管用高合金を提案している。 Patent Document 1 discloses a high alloy steel for waste heat boiler pipes for waste waste waste, and produces molten salt excellent in stress corrosion cracking resistance and intergranular corrosion resistance for waste heat boiler pipes in waste incinerators. We are proposing alloys.
特許文献２には、熱間加工性に優れた耐高温腐食用鋼が開示されている。 Patent Document 2 discloses a steel for high temperature corrosion resistance having excellent hot workability.
特許文献３には、廃棄物廃却プラントボイラ伝熱管用高耐食性オーステナイト系ステンレス鋼が開示されており、溶融塩腐食および酸露点腐食に優れた耐粒界腐食を有するボイラ伝熱管用オーステナイト系ステンレス鋼を提案している。 Patent Document 3 discloses a highly corrosion-resistant austenitic stainless steel for waste disposal plant boiler heat transfer tubes, and has excellent intergranular corrosion resistance for molten salt corrosion and acid dew point corrosion. Austenitic stainless steel for boiler heat transfer tubes. We are proposing steel.
特許文献４には、砂による摩耗に優れたノズル材質が開示されている。 Patent Document 4 discloses a nozzle material excellent in wear due to sand.
バイオマス用の空気吹き出しノズルは高温環境下で使用されるため、鋳物でノズルを製造する場合は、流動層媒体の砂等による摩耗と、塩化、硫化、酸化による腐食の対策が重要となる。 Since the air blowing nozzle for biomass is used in a high temperature environment, it is important to take measures against wear of the fluidized layer medium due to sand and the like and corrosion due to chloride, sulfurization, and oxidation when manufacturing the nozzle by casting.
バイオマスボイラの炉床で用いる空気吹き出しノズルには、耐熱鋳鋼（ＪＩＳ Ｇ ５１２２ ＳＣＨ２２）あるいはステンレス鋳鋼（ＪＩＳ Ｇ ５１２１のＳＣＳ１３Ａ）などが適用されているが、砂による摩耗、塩化、硫化、酸化の腐食により耐用寿命は著しく短い。 Heat-resistant cast steel (JIS G 5122 SCH22) or stainless cast steel (JIS G 5121 SCS13A) is applied to the air blowing nozzle used in the hearth of the biomass boiler, but wear due to sand, chloride, sulfide, and oxidation corrosion. Due to this, the service life is extremely short.
特許文献１〜３は、塑性加工品に関し、熱間鍛造などの塑性加工が施されている。これに対し、空気吹き出しノズルは、所定の形状に鋳込んだ後に塑性加工を施さない鋳物品である。鋳物の合金組織は、塑性加工により生じた合金組織とは異なり、鋳造時の凝固組織がそのまま残ったものである。鋳物は、鋳型に溶湯を流し込むことにより任意の形状が得られるので、塑性加工品に比べて製造が容易であるという利点がある。一方、鋳造の凝固組織は、偏析が大きく、結晶粒が粗大であるため、耐腐食性に影響を及ぼすと言われている。 Patent Documents 1 to 3 relate to a plastic working product and have been subjected to plastic working such as hot forging. On the other hand, the air blowing nozzle is a cast article that is cast into a predetermined shape and then not subjected to plastic working. The alloy structure of the casting is different from the alloy structure produced by plastic working, and the solidified structure at the time of casting remains as it is. Since an arbitrary shape can be obtained by pouring molten metal into a mold, a casting has an advantage that it is easier to manufacture than a plastic working product. On the other hand, the solidified structure of casting is said to affect the corrosion resistance because the segregation is large and the crystal grains are coarse.
特許文献４には砂による摩耗に優れたノズルに用いることができる鋳鉄が開示されているが、複合ガス雰囲気中における耐腐食性について、改善の余地がある。 Patent Document 4 discloses cast iron that can be used for nozzles that are excellent in wear due to sand, but there is room for improvement in corrosion resistance in a composite gas atmosphere.
本発明は、上記の事情に鑑み、高温域の複合ガス雰囲気中で優れた耐摩耗性、耐腐食性を有する、バイオマス用空気吹き出しノズルに用いることができる鋳物を提供することを課題とする。 In view of the above circumstances, it is an object of the present invention to provide a casting that has excellent wear resistance and corrosion resistance in a complex gas atmosphere in a high temperature region and can be used as an air blowing nozzle for biomass.
本発明者らは、高温域の複合ガス雰囲気中で優れた耐腐食性を有する鋼鋳物の成分組成について鋭意検討した。 The present inventors have diligently studied the composition of steel castings having excellent corrosion resistance in a composite gas atmosphere in a high temperature range.
ＣｒはＨ２Ｏ、Ｏ２などの酸化雰囲気において、安定なＣｒ２Ｏ３もしくはＦｅＣｒ２Ｏ４を生成して耐高温腐食性に有効である。しかし、ＳＯ２あるいはＣｌ２を含有する燃焼ガス雰囲気では、ＣｒＳまたはＣｒＣｌ２を生成する。硫化反応が進行するとマトリックスのＣｒ量が減少して耐腐食性が低下し、同様に塩化反応が進行すると反応生成物が蒸発することでマトリックスのＣｒ量が減少し耐腐食性が低下する。このような、マトリックスのＣｒ量の減少による耐腐食性の低下を抑制するためには、Ｓｉの添加が有効であると知られている。 Cr produces stable Cr 2 O 3 or Fe Cr 2 O 4 in an oxidizing atmosphere such as H 2 O and O 2 , and is effective for high temperature corrosion resistance. However, in a combustion gas atmosphere containing SO 2 or Cl 2 , CrS or CrCl 2 is produced. As the sulfurization reaction progresses, the amount of Cr in the matrix decreases and the corrosion resistance decreases. Similarly, when the chloride reaction proceeds, the reaction product evaporates, so that the amount of Cr in the matrix decreases and the corrosion resistance decreases. It is known that the addition of Si is effective in suppressing such a decrease in corrosion resistance due to a decrease in the amount of Cr in the matrix.
本発明者らは、さらに、Ｎｉを多量に添加すると腐食生成物とＮｉが濃化したマトリックスの混在した安定な被膜を生成して、高温域の塩素、硫黄、酸素の複合ガス雰囲気中で耐腐食性を向上させることを見出した。 Furthermore, when a large amount of Ni is added, the present inventors form a stable film in which a corrosion product and a matrix in which Ni is concentrated are mixed, and are resistant to a complex gas atmosphere of chlorine, sulfur, and oxygen in a high temperature range. It has been found to improve corrosiveness.
本発明は上記の知見に基づきなされたものであって、その要旨は以下のとおりである。 The present invention has been made based on the above findings, and the gist thereof is as follows.
（１）質量％で、Ｃ：０．０８％以下、Ｓｉ：２．５０〜４．００％、Ｍｎ：０．３０〜２．００％、Ｃｒ：２０．００〜３０．００％、Ｎｉ：３５．００〜４５．００％、Ｓｅ：０〜０．５０％、Ｔｅ：０〜０．１００％、Ｂｉ：０〜０．１０％、Ｍｏ：０〜３．００％、Ｃｅ、Ｌａ、Ｍｇの１種以上：０〜０．２０％、及びＷ、Ｎｂ、Ｔｉ、Ａｌの１種以上：０〜２．００％を含有し、残部がＦｅ及び不純物であることを特徴とするオーステナイト・ステンレス鋼鋳物。 (1) In mass%, C: 0.08% or less, Si: 2.50 to 4.00%, Mn: 0.30 to 2.00%, Cr: 20.00 to 30.00%, Ni: 35.00 to 45.00%, Se: 0 to 0.50%, Te: 0 to 0.100%, Bi: 0 to 0.10%, Mo: 0 to 3.00%, Ce, La, Mg Austenitic stainless steel containing 1 or more of: 0 to 0.20% and 1 or more of W, Nb, Ti, Al: 0 to 2.00%, and the balance being Fe and impurities. Steel casting.
（２）質量％で、Ｓｅ：０．００１％〜０．５０％、Ｔｅ：０．００１％〜０．１００％、及びＢｉ：０．００１％〜０．１０％の１種以上を含有することを特徴とする前記（１）のオーステナイト・ステンレス鋼鋳物。 (2) Containing at least one of Se: 0.001% to 0.50%, Te: 0.001% to 0.100%, and Bi: 0.001% to 0.10% in mass%. The austenitic stainless steel casting according to (1) above.
（３）質量％で、Ｍｏ：１．００〜３．００％含有することを特徴とする前記（１）又は（２）のオーステナイト・ステンレス鋼鋳物。 (3) The austenitic stainless steel casting according to (1) or (2) above, which contains Mo: 1.00 to 3.00% in mass%.
（４）質量％で、Ｃｅ、Ｌａ、及びＭｇの１種以上を、０．００１〜０．２０％含有することを特徴とする前記（１）〜（３）のいずれかのオーステナイト・ステンレス鋼鋳物。 (4) The austenitic stainless steel according to any one of (1) to (3) above, which contains 0.001 to 0.20% of one or more of Ce, La, and Mg in mass%. casting.
（５）質量％で、Ｗ、Ｎｂ、Ｔｉ、Ａｌの１種以上を、０．００１〜２．００％含有することを特徴とする前記（１）〜（４）のいずれかのオーステナイト・ステンレス鋼鋳物。 (5) Austenitic stainless steel according to any one of (1) to (4) above, which contains 0.001 to 2.00% of one or more of W, Nb, Ti and Al in mass%. Steel casting.
（６）前記（１）〜（５）のいずれかのオーステナイト・ステンレス鋼鋳物からなる空気吹き出しノズル。 (6) An air blowing nozzle made of the austenitic stainless steel casting according to any one of (1) to (5) above.
本発明によれば、高温域の複合ガス雰囲気中で耐腐食性を有する、バイオマス用空気吹き出しノズル鋳物を提供することが可能となる。 According to the present invention, it is possible to provide an air blowing nozzle casting for biomass having corrosion resistance in a complex gas atmosphere in a high temperature region.
以下、本発明を詳細に説明する。はじめに、本発明の耐熱耐摩耗鋳鉄の成分組成について説明する。以下、成分組成についての「％」は「質量％」を意味するものとする。 Hereinafter, the present invention will be described in detail. First, the component composition of the heat-resistant and wear-resistant cast iron of the present invention will be described. Hereinafter, "%" for the component composition shall mean "mass%".
Ｃは、鋼中のＣｒと結合して結晶粒界にＣｒ炭化物として析出する。Ｃｒが炭化物として析出すると、基地のCr濃度が低下して耐高温酸化性が劣るので、Ｃの含有量は少ないほうが好ましい。したがって、Ｃの含有量は０．０８％以下、好ましくは０．０５％以下とする。 C is bonded to Cr in the steel and precipitated as Cr carbide at the grain boundaries. When Cr is precipitated as a carbide, the Cr concentration of the matrix is lowered and the high temperature oxidation resistance is inferior. Therefore, it is preferable that the content of C is small. Therefore, the C content is 0.08% or less, preferably 0.05% or less.
Ｓｉは、脱酸剤として働く元素であり、また、特に高温における耐酸化性、耐食性を向上させるために必要な元素である。この効果を十分に得るためにＳｉの含有量は２．５０％以上とする。シグマ脆化を考慮して、Ｓｉの含有量は４．００％以下、好ましくは３．５０％以下とする。 Si is an element that acts as an antacid, and is also an element necessary for improving oxidation resistance and corrosion resistance, especially at high temperatures. In order to obtain this effect sufficiently, the Si content is 2.50% or more. Considering sigma embrittlement, the Si content is 4.00% or less, preferably 3.50% or less.
Ｍｎは、オーステナイト形成元素であり、また、脱酸剤、脱硫剤として有用な成分である。その効果を十分に得るために、Ｍｎの含有量は０．３０％以上とする。鋳鉄の脆化の防止や、クリープ強度の低下の防止の観点から、Ｍｎの含有量の上限は２．００％以下とする。 Mn is an austenite-forming element and is a useful component as an antacid and a desulfurizing agent. In order to obtain the effect sufficiently, the Mn content is set to 0.30% or more. From the viewpoint of preventing embrittlement of cast iron and prevention of decrease in creep strength, the upper limit of the Mn content is set to 2.00% or less.
Ｃｒは高温強度、および高温での耐酸化性を向上する元素である。その効果を十分に得るために、Ｃｒの含有量は２０．００％とする。バイオマスボイラのような、溶融塩化物が付着するような環境下ではＣｒの含有量が多くなりすぎると、揮発性のＣｒ２Ｏ２Ｃｌ２が形成され、耐高温酸化性が低下するので、Ｃｒの含有量は３０．００％以下とする。 Cr is an element that improves high-temperature strength and high-temperature oxidation resistance. In order to obtain the effect sufficiently, the Cr content is set to 20.00%. If the Cr content is too high in an environment such as a biomass boiler where molten chloride adheres, volatile Cr 2 O 2 Cl 2 will be formed and the high temperature oxidation resistance will decrease. The content of is 30.00% or less.
Ｎｉはオーステナイト形成元素であり、高温強度や高温での耐食性を向上する元素である。また、加工硬化量を増し、耐摩耗性を高める効果がある。材料コストと効果のバランスを考慮し、Ｎｉの含有量は３５．００〜４５．００％とする。 Ni is an austenite-forming element, which is an element that improves high-temperature strength and corrosion resistance at high temperatures. It also has the effect of increasing the amount of work hardening and increasing wear resistance. Considering the balance between material cost and effect, the Ni content is set to 35.00 to 45.00%.
一般にオーステナイト・ステンレス鋼は、難削鋼であるため、切削加工のコストがかかるという課題がある。本発明のオーステナイト・ステンレス鋼鋳物には被削性を向上させるために、さらに、Ｓｅ、Ｔｅ、Ｂｉの１種以上を含有させることができる。これらの元素は少量の添加でも被削性を向上させる効果があるが、添加の効果を十分に得るには、どの元素を添加する場合でも、０．００１％以上添加するのが好ましい。これらの元素の含有量が多すぎても効果が飽和するだけなので、含有量の上限は、Ｓｅは０．５０％、Ｔｅは０．１００％、Ｂｉは０．１０％とする。 In general, austenitic stainless steel is a difficult-to-cut steel, so there is a problem that cutting costs are high. The austenitic stainless steel casting of the present invention may further contain one or more of Se, Te and Bi in order to improve machinability. Although these elements have the effect of improving machinability even when added in a small amount, it is preferable to add 0.001% or more regardless of which element is added in order to obtain a sufficient effect of the addition. If the content of these elements is too large, the effect will only be saturated. Therefore, the upper limit of the content is 0.50% for Se, 0.100% for Te, and 0.10% for Bi.
Ｓｅ、Ｔｅ及びＢｉを添加することで、切削抵抗の減少、工具寿命の延長、構成刃先の抑制、仕上げ面性状の改善、切りくず破砕性の改善という効果が得られる。 By adding Se, Te and Bi, the effects of reducing cutting resistance, extending the tool life, suppressing the built-up edge, improving the finished surface properties, and improving the chip crushability can be obtained.
なお、これらの元素を添加すると熱間加工性が低下するため、鍛造や圧延を施すには好ましくない。本発明のオーステナイト・ステンレス鋼鋳物は鋳造ままの鋳物であるから、熱間加工性の低下は大きな問題とはならず、Ｓｅ、Ｔｅ及びＢｉの添加が被削性向上に有効である。 It should be noted that the addition of these elements reduces the hot workability, which is not preferable for forging or rolling. Since the austenitic stainless steel casting of the present invention is a casting as it is cast, the decrease in hot workability does not pose a big problem, and the addition of Se, Te and Bi is effective in improving the machinability.
本発明のオーステナイト・ステンレス鋼鋳物には、さらに、Ｍｏを含有させることができる。Ｍｏはオーステナイト中に固溶して、耐摩耗性を高める効果がある。この効果は少量の添加でも得られるが、添加の効果を十分に得るには、Ｍｏの含有量を１．００％以上とするのが好ましい。添加の効果を十分に得るには、どの元素を添加する場合でも、０．００１％以上添加するのが好ましい。Ｍｏの含有量が多くても、効果は飽和し、また、偏析による靭性低下を生じる可能性があるので、上限は３．００％とする。 The austenitic stainless steel casting of the present invention can further contain Mo. Mo has the effect of increasing wear resistance by dissolving in austenite. Although this effect can be obtained even with a small amount of addition, the Mo content is preferably 1.00% or more in order to obtain a sufficient effect of the addition. In order to obtain a sufficient effect of the addition, it is preferable to add 0.001% or more regardless of which element is added. Even if the content of Mo is large, the effect is saturated and the toughness may decrease due to segregation. Therefore, the upper limit is set to 3.00%.
本発明のオーステナイト・ステンレス鋼鋳物には、さらに、Ｃｅ、Ｌａ、Ｍｇの１種以上を含有させることができる。これらの元素はＳと結びついてＳの粒界偏析を抑え、靭性の低下を抑制することができる。これらの元素は少量の添加でもＣｒ硫化物の析出を抑制する効果があるが、添加の効果を十分に得るには、どの元素を添加する場合でも、０．００１％以上添加するのが好ましい。各元素とも、含有量が０．２０％を超えると効果が飽和するので、上限は０．２０％とする。 The austenitic stainless steel casting of the present invention may further contain one or more of Ce, La and Mg. These elements can be combined with S to suppress the grain boundary segregation of S and suppress the decrease in toughness. Although these elements have the effect of suppressing the precipitation of Cr sulfide even when added in a small amount, it is preferable to add 0.001% or more regardless of which element is added in order to obtain a sufficient effect of the addition. Since the effect of each element is saturated when the content exceeds 0.20%, the upper limit is set to 0.20%.
本発明のオーステナイト・ステンレス鋼鋳物には、さらに、Ｗ、Ｎｂ、Ｔｉ、Ａｌの１種以上を含有させることができる。これらの元素は炭化物を形成しやすいので、鋼中のＣを固定してＣｒ炭化物の析出を抑制することができ、高温強度の低下を防ぐことができる。これらの元素は少量の添加でもＣｒ炭化物の析出を抑制する効果があるが、添加の効果を十分に得るには、どの元素を添加する場合でも、０．００１％以上添加するのが好ましい。各元素とも、含有量が２．００％を超えると効果が飽和するので、上限は２．００％とする。 The austenitic stainless steel casting of the present invention may further contain one or more of W, Nb, Ti and Al. Since these elements easily form carbides, C in the steel can be fixed to suppress the precipitation of Cr carbides, and a decrease in high temperature strength can be prevented. These elements have the effect of suppressing the precipitation of Cr carbides even when added in a small amount, but in order to obtain a sufficient effect of the addition, it is preferable to add 0.001% or more regardless of which element is added. Since the effect of each element is saturated when the content exceeds 2.00%, the upper limit is set to 2.00%.
成分組成の残部は、Ｆｅ及び不可避的不純物である。不可避的不純物とは、本発明で規定する成分組成を有する鋳物を工業的に製造する際に、原料や製造環境等から不可避的に混入するものをいい、たとえば、Ｐ、Ｓがあげられる。Ｐ、Ｓは、通常０．０３０％以下程度、鋳物に不可避的に混入する。 The rest of the composition is Fe and unavoidable impurities. The unavoidable impurities refer to those that are unavoidably mixed from the raw materials, the manufacturing environment, etc. when the casting having the component composition specified in the present invention is industrially manufactured, and examples thereof include P and S. P and S are unavoidably mixed in the casting in an amount of about 0.030% or less.
本発明の製造方法は、特に限定されるものではなく、常法によればよい。はじめに、上述した成分組成を有する溶湯を調整し、溶湯を鋳型に注湯し、注湯された溶湯を冷却して凝固させる。本発明鋳鉄は原則として鋳放しのまま使用されるが、必要に応じて溶体化処理をすることができる。 The production method of the present invention is not particularly limited, and a conventional method may be used. First, a molten metal having the above-mentioned component composition is prepared, the molten metal is poured into a mold, and the poured molten metal is cooled and solidified. As a general rule, the cast iron of the present invention is used as it is, but it can be solution-treated if necessary.
本発明の成分組成を有する溶湯を鋳造することにより、特別な製法を用いることなく、鋳造ままで優れた高温耐腐食性を有するオーステナイト・ステンレス鋼鋳物を得ることが可能である。 By casting a molten metal having the component composition of the present invention, it is possible to obtain an austenitic stainless steel casting having excellent high-temperature corrosion resistance as it is cast without using a special manufacturing method.
なお、本発明のオーステナイト・ステンレス鋼鋳物は、所定の形状の鋳型に鋳込んだ後に塑性加工を施さない鋼であり、熱間圧延や鍛造のような塑性加工が施された合金とは区別される。すなわち、鋳物は合金組織として鋳造したままの凝固組織が残ったものであるのに対し、塑性加工が施された合金は加工により生じた合金組織を有するものであり、その組織は大きく異なるものである。本発明の鋳物では、結晶粒の大きさは０．２〜２．０ｍｍ程度となる。 The austenite stainless steel casting of the present invention is a steel that is not subjected to plastic working after being cast in a mold having a predetermined shape, and is distinguished from an alloy that has been subjected to plastic working such as hot rolling or forging. To. That is, while the casting has a solidified structure as it is cast as an alloy structure, the plastic-processed alloy has an alloy structure produced by the processing, and the structure is significantly different. is there. In the casting of the present invention, the size of crystal grains is about 0.2 to 2.0 mm.
以下、実施例を用いて、本発明をより具体的に説明する。以下に挙げる例は本発明の実施態様の一例であり、本発明が以下の実施例により制限されるものでないことはいうまでもない。 Hereinafter, the present invention will be described in more detail with reference to Examples. It goes without saying that the examples given below are examples of embodiments of the present invention, and the present invention is not limited by the following examples.
［実施例１］
表１に示す成分組成を有する外径７０ｍｍ、内径５６ｍｍの円筒形の空気吹き出しノズルを、塩素、硫黄、酸素雰囲気のバイオマスボイラ内に設置して、実機実験を行った。設置してから１年後に、ノズルの外径をノギスで測定し、直径の減少量で、ノズルの耐摩耗性、耐腐食性を評価した。表１にそれぞれの成分組成を有するノズルについて測定した直径の減少量を示す。
[Example 1]
A cylindrical air blowing nozzle having an outer diameter of 70 mm and an inner diameter of 56 mm having the component composition shown in Table 1 was installed in a biomass boiler having a chlorine, sulfur, and oxygen atmosphere, and an actual machine experiment was conducted. One year after the installation, the outer diameter of the nozzle was measured with a caliper, and the wear resistance and corrosion resistance of the nozzle were evaluated by the amount of decrease in diameter. Table 1 shows the amount of diameter reduction measured for nozzles having each component composition.
表１に示すＮｏ．１〜１２は本発明の鋼を用いた発明例、Ｎｏ．２１〜２２は一般的な鋼を用いた比較例である。表１に示すように、本発明の鋳物を用いたノズルは、バイオマスボイラ中で使用した場合であっても摩耗、腐食が小さく、高温域における耐摩耗性、耐腐食性に優れていることが確認できた。 No. shown in Table 1. Examples 1 to 12 are examples of the invention using the steel of the present invention, No. 21 to 22 are comparative examples using general steel. As shown in Table 1, the nozzle using the casting of the present invention has low wear and corrosion even when used in a biomass boiler, and has excellent wear resistance and corrosion resistance in a high temperature range. It could be confirmed.
［実施例２］
表１に示したＮｏ．５、８、９、１０の成分組成を有する鋳物について、ドリル（ＳＫＨ５１、ドリル径５．０ｍｍ）を用いて、切削油なし、切削速度：２０ｍ／ｍｉｎ、１回転あたりの送り量：０．１ｍｍ／ｒｅｖで、深さ２０ｍｍの穴あけ加工を繰り返し行い、加工ができなくなるまでの穴数を求め加工性能を評価した。表２に結果を示す。加工能率は、Ｎｏ．５の鋳物で加工ができなくなるまでの回数を１としたときの加工可能回数の比である。
[Example 2]
No. 1 shown in Table 1. For castings having a composition of 5, 8, 9, and 10, using a drill (SKH51, drill diameter 5.0 mm), no cutting oil, cutting speed: 20 m / min, feed rate per rotation: 0.1 mm With / rev, drilling with a depth of 20 mm was repeated, and the number of holes until the drilling became impossible was obtained and the machining performance was evaluated. The results are shown in Table 2. The processing efficiency is No. It is a ratio of the number of times that can be processed when the number of times until the casting cannot be processed in 5 is 1.
被削性元素が添加された、Ｎｏ．８、９、１０は、実施例１で示したとおり高い耐腐食性を有すると同時に、Ｎｏ．５と比較して高い加工性能を示すことが確認できた。Ｎｏ．２３は、成分組成が本発明の鋳物の成分組成の範囲内である鍛造鋼である。Ｎｏ．２３の鋼は、本発明の鋳物と同程度の加工性能を示した。しかしながら、Ｎｏ．８と同様に被削性向上元素を添加したＮｏ．２４は熱間加工性が低下したため、鍛造割れを生じ、目的の鋼を得ることはできなかった。
Claims (6)
Ｃ：０．０８％以下、
Ｓｉ：２．５０〜４．００％、
Ｍｎ：０．３０〜２．００％、
Ｃｒ：２０．００〜３０．００％、
Ｎｉ：３５．００〜４５．００％、
Ｓｅ：０〜０．５０％、
Ｔｅ：０〜０．１００％、
Ｂｉ：０〜０．１０％、
Ｍｏ：０〜３．００％、
Ｃｅ、Ｌａ、Ｍｇの１種以上：０〜０．２０％、及び
Ｗ、Ｎｂ、Ｔｉ、Ａｌの１種以上：０〜２．００％
を含有し、残部がＦｅ及び不純物である
ことを特徴とするオーステナイト・ステンレス鋼鋳物。 By mass%
C: 0.08% or less,
Si: 2.50 to 4.00%,
Mn: 0.30 to 2.00%,
Cr: 20.00 to 30.00%,
Ni: 35.00-45.00%,
Se: 0-0.50%,
Te: 0 to 0.100%,
Bi: 0 to 0.10%,
Mo: 0-3.00%,
One or more of Ce, La, Mg: 0 to 0.20%, and one or more of W, Nb, Ti, Al: 0 to 2.00%
Austenitic stainless steel castings containing Fe and impurities in the balance.
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| JPS5779153A (en) * | 1980-10-31 | 1982-05-18 | Nippon Steel Corp | Burning resistant iron alloy for oxygen duct |
| JPS59100301A (en) * | 1982-12-01 | 1984-06-09 | 株式会社日立製作所 | Boiler tube for plant containing combustion of coal |
| JPH10183305A (en) * | 1996-12-26 | 1998-07-14 | Mitsubishi Heavy Ind Ltd | High strength, corrosion resistant and heat resistant alloy |
| JP2003034840A (en) * | 2001-07-23 | 2003-02-07 | Nippon Steel Corp | Steel for machine structure superior in machinability |
| JP2017078198A (en) * | 2015-10-20 | 2017-04-27 | 新報国製鉄株式会社 | Heat-resistant wear-resistant cast iron |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5779153A (en) * | 1980-10-31 | 1982-05-18 | Nippon Steel Corp | Burning resistant iron alloy for oxygen duct |
| JPS59100301A (en) * | 1982-12-01 | 1984-06-09 | 株式会社日立製作所 | Boiler tube for plant containing combustion of coal |
| JPH10183305A (en) * | 1996-12-26 | 1998-07-14 | Mitsubishi Heavy Ind Ltd | High strength, corrosion resistant and heat resistant alloy |
| JP2003034840A (en) * | 2001-07-23 | 2003-02-07 | Nippon Steel Corp | Steel for machine structure superior in machinability |
| JP2017078198A (en) * | 2015-10-20 | 2017-04-27 | 新報国製鉄株式会社 | Heat-resistant wear-resistant cast iron |
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