1253473 九、發明說明： 【發明所屬之技術領域】 本項發明屬雷射表面處理技術。 【先前技術】 火力電廠汽機低壓段之末級葉片經長期運轉後，易於 葉片導引端區產生沖蝕損傷，降低機組之運轉效率，嚴重 者會影響機組之運轉安全。因此，機組原製造廠家通常會 在葉片之沖蝕區（約為1/10〜1/4葉面寬；1/5〜1/3葉面 長），以硬銲方式覆蓋一片約0.5〜1 mm厚之Stellite Νο·6 strip，以增力口該區之抗沖蚀性。由於stellite strip不易與 葉片導引端曲度完全吻合，故其大小與形狀受到很大限 制。一般而言，葉片沖蝕區之範圍較Stellite strip所覆蓋 之區域為大，所以經常傷及母材。此損傷之葉片即無法以 更換Stellite Νο·6 strip方式進行硬銲修補。汽機末級葉片 之外觀如第一圖所示，可區分為葉片根槽部份1 (Root)， 葉面部份2 (Face)，葉片榫頭3 (Shroud)，葉片耳狀銲接 連接點4 (Lashing lugs)，葉片導引端抗沖蝕區5 (Erosion resistance region of leading edge)，硬銲 Stellite strip 區 14，葉片導引端6，葉片尾流端7(Trailingedge)。 火力電廠汽機低壓段末級葉片之主要材料為17-4 PH 析出硬化型不銹鋼或麻田散鐵系403不銹鋼。為改善上述 末級葉片硬銲覆銲缺點及增強其抗沖蝕性質，針對麻Θ散 鐵系 403 不銹鋼葉片，文獻[V. Bedogni et· al·，“Laser and Electron Beam Surface Hardening of Turbine Blades” Laser 12534731253473 IX. Description of the invention: [Technical field to which the invention pertains] This invention is a laser surface treatment technique. [Prior Art] After the long-term operation of the low-end section of the low-pressure section of the steam turbine of the thermal power plant, it is easy to produce erosion damage in the leading end area of the blade, which reduces the operating efficiency of the unit, and seriously affects the operation safety of the unit. Therefore, the original manufacturer of the unit usually covers the area of the blade (about 1/10~1/4 of the leaf surface width; 1/5~1/3 of the leaf surface length), and covers a piece of about 0.5~1 by brazing. Mm thick Stellite Νο·6 strip, to enhance the erosion resistance of this area. Since the stellite strip is not easily matched with the blade guide end curvature, its size and shape are greatly limited. In general, the extent of the blade erosion zone is larger than the area covered by the Stellite strip, so the base metal is often damaged. The blade of this damage cannot be brazed by replacing the Stellite Νο·6 strip. The appearance of the final blades of the turbine can be divided into the root groove part 1 (Root), the blade surface part 2 (Face), the blade head 3 (Shroud), and the blade ear-shaped welding connection point 4 (shown in the first figure). Lashing lugs), the Erosion resistance region of leading edge, the brazed Stellite strip region 14, the blade leading end 6, and the trailing edge 7 (Trailingedge). The main material of the last stage blade of the low-pressure section of the steam turbine of the thermal power plant is 17-4 PH precipitation hardening type stainless steel or Ma Tian scattered iron type 403 stainless steel. In order to improve the shortcomings of the above-mentioned last-stage blade brazing and welding and enhance its anti-erosion properties, the paper discusses the 403 stainless steel blades of the Θ Θ 散 散, [V. Bedogni et al., "Laser and Electron Beam Surface Hardening of Turbine Blades" Laser 1253473
Advanced Materials Processing 87 Osaka，May 1987, PP.567-572 ]及相關專利[歐洲專利編號Ep〇5〇7131B1 ]， 曹提出以雷射束或電子束等高能量密度熱源進行葉片之 表面硬化處理方式。至於17-4 PH析出硬化型不銹鋼末級 葉片尚未有任何相關的雷射束或電子束等高能量密度熱 源進行葉片之抗沖蝕表面處理方法發表。 【發明内容】 為提升17-4 PH析出硬化型不銹鋼汽機末級葉片之 抗沖蝕能力’本項專利發明為應用自行設計之近似同軸或 同軸環氣式雷射喷覆處理喷嘴（國科會報告 NSC902216E002040 “雷射輔助金屬直接堆積製程研發與 應用”及NSC912216E002032 “雷射表面薄層喷覆之製程 開發”)進行17-4 PH不銹鋼末級葉片導引端(Leading edge) 抗沖蝕區之雷射喷覆處理。17-4 PH析出硬化型不銹鋼末 級葉片’ 一般皆經固溶（l〇38°C/lhr +空冷）與H1150M (76〇C/2hr +空冷+ 621°C/4hr +空冷）熱處理後使 用。而相關研究報告[國科會88年度電力科技產業學術合 作研究技畫應力比與負荷頻率對析出硬化型汽機葉片不 銹鋼腐蝕疲勞性質之影響”]及文獻[Tsay et· al.，C〇rrosi〇nAdvanced Materials Processing 87 Osaka, May 1987, PP.567-572] and related patents [European Patent No. Ep〇5〇7131B1], Cao proposed surface hardening treatment of blades with high energy density heat sources such as laser beam or electron beam . As for the 17-4 PH precipitation hardening type stainless steel final stage blade, there is no relevant high-density heat source such as laser beam or electron beam for the anti-erosion surface treatment method of the blade. SUMMARY OF THE INVENTION In order to improve the erosion resistance of the final blade of the 17-4 PH precipitation hardening type stainless steel steam turbine, the patented invention is a self-designed approximate coaxial or coaxial annular gas laser spray treatment nozzle (National Science and Technology Association) Report NSC902216E002040 "Development and Application of Laser Auxiliary Metal Direct Stacking Process" and NSC912216E002032 "Process Development of Laser Surface Thin Layer Spraying") 17-4 PH Stainless Steel Last Stage Blade Leading Edge Anti-Erosion Area Laser spray treatment. 17-4 PH precipitation hardening type stainless steel final stage 'Generally used after solid solution (l〇38°C/lhr + air cooling) and H1150M (76〇C/2hr + air cooling + 621°C/4hr + air cooling) . And related research report [National Science and Technology Association 88 years of power technology industry academic cooperation research and technology stress ratio and load frequency on the corrosion fatigue properties of precipitation hardening turbine blade stainless steel" and literature [Tsay et al., C〇rrosi〇 n
Science 44 (2002) PP.2101-2118 ’ “Notch tensile properties of laser-surface-annealed 17-4 pH stainless steel in hydrogen-related environments’’]顯示，17_4 pH 材料經固 1253473 溶與H900(482 °C /lhr+空冷）時效處理，較經固溶與 H1150M處理者有較佳之抗腐蝕疲勞特性，並較經固溶與 H1025 (552°C/lhr +空冷;)處理者具有較低之硫化氫環境 缺口拉伸強度損失。 本發明為應用與雷射同軸之送粉喷嘴，進行17_4 ΡΉ 不銹鋼末級葉片抗沖蝕區之雷射喷覆處理，並應用後熱處 理技術提升此區域之抗沖蝕能力。本發明雷射喷覆處理技 術，可應用於17-4 PH新葉片之生產製程或受損傷舊葉片 之再生製程。雷射噴覆處理所用之粉末為與葉片材料相似 成份之17-4 PH合金粉末。經雷射喷覆處理之葉片橫斷面 如第二圖所示’可區分為葉片導引端雷射喷覆處理區8， 葉片母材未受雷射熱影響區2，雷射喷覆處理之熱影響區 1〇,葉片導引端喷覆處理起始點9 (係由與葉片彎矩中心線 13垂直之垂線11，通過與葉片導引端壓力侧外緣相切之 切點’由該切點定為葉片導引端喷覆處理起始點），葉片導 引端6為葉片在運轉中之沖蝕方向12作用區，7為葉片尾 流端。雷射噴覆處理之葉片稍經研磨加工後，施以H9〇〇 (482°C/lhr +空冷）時效與應力消除處理後之巨觀金相照 片如第三圖所示。由第三圖顯示，葉片經雷射喷覆處理可 得到相當均勻之喷覆層，噴覆層經H900時效處理後，其 硬度值可達430Hv以上。第二圖中葉片導引端經雷射噴覆 處理及H900處理硬化區8，其硬度值分佈為 430Hv〜490Hv，葉片母材未受雷射熱影響區2,其硬度值 為300Hv〜320Hv，雷射嘴覆熱影響區10小於〇·5 mm，其 1253473 硬度分佈為330Hv〜420Hv。由第三圖顯示，雷射喷覆層之 厚度超過1 mm，且其硬度值高於Stellite strip之420Hv。 上述雷射喷覆層依抗沖#硬化層之需求深度（0.5〜2 mm)，可由調整雷射功率密度及送粉流量而達成。 本項發明雷射喷覆製程中，控制雷射參數與粉末流 量，使17-4 PH粉末吸收大部份之雷射能量，故在抗沖蝕 區所生成的熱影響區可降至0·5 mm以下。由於本製程之 熱輸入量低於320 J/mm，且大部份熱量由粉末吸收，故 葉片之殘留應力可降至最低程度，葉片雷射喷覆並經H900 _ 處理後，除可降低殘留應力外，亦可使喷覆層之硬度大幅 提昇至430Hv〜490Hv ’但不致影響母材的硬度。喷覆製程 使用與葉片同材質之合金粉末，可避免喷覆區與母材因物 理與機械性質的差異，而造成殘留應力不易消除的困擾 [Yang et. aL；?Laser Welding of 422 Stainless Steel withScience 44 (2002) PP.2101-2118 '"Notch tensile properties of laser-surface-annealed 17-4 pH stainless steel in hydrogen-related environments''] shows that 17_4 pH material is solidified to 1,253,347 and H900 (482 °C) /lhr+air cooling) aging treatment, better corrosion resistance and fatigue resistance than those with solid solution and H1150M treatment, and lower hydrogen sulfide environment gap than those treated with solid solution and H1025 (552°C/lhr + air cooling;) The invention relates to a laser spray nozzle which is applied coaxially with a laser, and performs laser spray treatment on the erosion resistance zone of the 17_4 ΡΉ stainless steel final blade, and applies post-heat treatment technology to improve the erosion resistance of the region. The laser spraying treatment technology of the invention can be applied to the production process of 17-4 PH new blade or the regeneration process of the damaged old blade. The powder used in the laser spraying treatment is 17-4 PH alloy similar to the blade material. Powder. The cross section of the blade treated by laser spraying can be divided into the laser-coated treatment area 8 of the blade leading end as shown in the second figure. The blade base material is not affected by the laser heat affected zone 2, and the laser spray Thermal impact of treatment Zone 1〇, the blade leading end spray treatment starting point 9 (by a perpendicular line 11 perpendicular to the blade bending moment centerline 13 and passing through a tangent point tangent to the outer edge of the pressure side of the blade leading end) The starting point of the blade leading end spraying treatment), the blade leading end 6 is the action area of the blade in the erosion direction of the blade 12, and 7 is the blade wake end. After the laser-sprayed blade is slightly ground, The macroscopic metallographic photographs after aging and stress-relieving treatment with H9〇〇 (482°C/lhr + air cooling) are shown in the third figure. From the third figure, the blades can be fairly evenly treated by laser spraying. The spray coating layer and the spray coating layer have a hardness value of 430Hv or more after H900 aging treatment. In the second figure, the blade guide end is subjected to laser spray treatment and H900 treatment hardening zone 8, and the hardness value distribution is 430Hv~ 490Hv, the blade base metal is not affected by the laser heat affected zone 2, its hardness value is 300Hv~320Hv, the laser mouth heat affected zone 10 is less than 〇·5 mm, and its 1253473 hardness distribution is 330Hv~420Hv. The thickness of the laser spray coating exceeds 1 mm and its hardness is higher than 420 Hv of the Stellite strip. The required depth of the laser spray coating according to the impact layer (0.5~2 mm) can be achieved by adjusting the laser power density and the powder feeding flow. In the laser spraying process of the invention, the laser parameters are controlled. The powder flow rate allows the 17-4 PH powder to absorb most of the laser energy, so the heat affected zone generated in the erosion resistant zone can be reduced to below 0.5 mm. Since the heat input of the process is less than 320 J/mm, and most of the heat is absorbed by the powder, the residual stress of the blade can be minimized. After the laser is sprayed and processed by H900_, the residue can be reduced. In addition to stress, the hardness of the spray coating can be greatly increased to 430Hv~490Hv' without affecting the hardness of the base metal. Spraying process Using alloy powder of the same material as the blade, it is possible to avoid the difference in physical and mechanical properties between the sprayed area and the base material, which causes the residual stress to be difficult to eliminate [Yang et. aL;?Laser Welding of 422 Stainless Steel with
Inconel 625 Filler Metal” ISIJ International，44(5)，2004， P.852-875]。 第四圖為比較雷射喷覆17-4 PH並經H900處理之試修 片（硬度值430Hv-490Hv)與移轉式電漿(pTA)銲覆Stellite Νο·6層之試片（硬度值約420Hv)，以30。進行乾氧化鋁（60 mesh)喷砂沖蝕試驗結果。第四圖之結果顯示，雷射喷覆 17-4 PH經H900時效處理之試片，在壓力2·5與4 Kg/cm2 喷砂沖蝕條件下，其結果與移轉式電漿銲覆Stellite Ν〇·6 層之試片的重量損失相近。 本項專利發明之雷射喷覆製程參數，視喷覆層厚度與 -11- 1253473 經H900處理後之硬化厚度而定，處理17-4 PH不銹鋼葉 片之雷射功率範圍含蓋1.5kW〜3.5kW，雷射掃瞄速度於 300 mm/min·〜1000 mm/min·間，送粉率則可應用於8 g/min.〜25 g/min·，雷射披覆處理覆銲層間重疊率分佈在 30%〜60%。雷射喷覆粉末成份範圍：c:0.025-0.045%， Cr:14-16%5 Ni:3-5%, Cu:3-5%, Si:0.4-0.65%, M〇:0.05-0.2%,Inconel 625 Filler Metal” ISIJ International, 44(5), 2004, P.852-875]. The fourth figure is a comparison of laser sprayed 17-4 PH and H900 treated (hardness value 430Hv-490Hv) The test piece of the Stellite Νο·6 layer (hardness value about 420Hv) was transferred to the transfer type plasma (pTA), and the dry alumina (60 mesh) blasting test result was carried out at 30. The result of the fourth figure shows , Laser sprayed 17-4 PH H900 aging test piece, under the conditions of pressure 2·5 and 4 Kg/cm2 blasting erosion, the result and transfer plasma welding Stellite Ν〇·6 layer The weight loss of the test piece is similar. The laser spray process parameters of the patented invention are determined according to the thickness of the spray coating and the hardening thickness of the -11-1253473 after H900 treatment, and the laser of the 17-4 PH stainless steel blade is processed. The power range covers 1.5kW~3.5kW, the laser scanning speed is between 300mm/min·~1000mm/min·, and the powder feeding rate can be applied to 8g/min.~25 g/min·, laser The overlapping ratio of the overlay coating between the coating and the overlay is between 30% and 60%. The range of the laser spray powder is: c: 0.025-0.045%, Cr: 14-16% 5 Ni: 3-5%, Cu: 3-5 %, Si: 0.4-0.65%, M〇: 0.05-0.2%,
Mn:0.1-0.6%, Nb:〇.2-〇.3%9 Fe:bal.，粉末粒度範圍含蓋 150μπι〜15μιη 〇Mn: 0.1-0.6%, Nb: 〇.2-〇.3% 9 Fe: bal., powder size range with cover 150μπι~15μιη 〇
【實施方式】 欲進行雷射噴覆處理之17-4 PH析出硬化型末級葉 片’以與雷射同轴之送粉噴嘴進行喷覆處理。喷覆之粉末， 、、工輸送氣體送人粉末流道，通過喷嘴出口再經雙環氣束作 用’形成集中之粉末流束，並與雷射光產生交互作用後， 溶融之母材（葉片）作用形成喷覆層。在雷射喷覆 控制雷射參數與粉末流量，使17-4 PH合金粉末 吸收大部分雷鼾铷旦 ^ ^ 0 ’僅少部分熔融母材，故可使熱影響 區降至最低程声 t ^ ^ ^ ^ 經噴覆處理之末級葉片再經H900時效[Embodiment] The 17-4 PH precipitation hardening type final blade "to be subjected to laser spraying treatment" is sprayed with a powder feeding nozzle coaxial with the laser. The sprayed powder, and the transporting gas are sent to the powder flow path, and through the nozzle outlet and then through the double-loop gas beam to form a concentrated powder stream, and interact with the laser light, the molten base material (blade) acts. A spray coating is formed. In the laser spray control laser parameters and powder flow, so that the 17-4 PH alloy powder absorbs most of the Thunderbolt ^ ^ 0 'only a small part of the molten base metal, so the heat affected zone can be reduced to the minimum sound t ^ ^ ^ ^ The final stage of the sprayed process is then H900 aging
與應力消除，可女A ^ 二大&增強喷覆區之抗沖蝕能力。 丄々、α上所揭路者僅為本發明之應用實例，並非用以限定 本發明之應用範圖^ 国’住何更動與潤飾，在不脫離本發明之 二嗜下’均應屬於本發明之適用範圍，因此本發明之 保遵範圍之申財利_所界定者為準。 -12- 1253473 【圖式簡單說明】 第一圖：汽機末級葉片之外觀示意圖。 第二圖··經雷射喷覆處理之末級葉片橫斷面外觀示意圖。 第三圖··經雷射喷覆處理之末級葉片橫斷面外觀金相。 第四圖：雷射喷覆17-4 PH不銹鋼並經H900時效處理之試 片與移轉式電漿銲覆Stellite Νο·6層之試片，以30 度角進行乾氧化鋁砂（60 mesh)喷砂沖蝕試驗結果 之重量損失變化。 【主要元件符號說明】 2:葉片母材未受雷射熱影響區 6 :葉片導引端 7 :葉片尾流端 8:葉片導引端雷射喷覆處理區 9:葉片導引端喷覆處理起始點 10:受雷射喷覆處理產生部份固溶之熱影響區 11 :與葉片彎矩中心線垂直之垂線 12:葉片水珠或氧化物沖蝕方向 13 :葉片彎矩中心線With stress relief, the female A ^ II & enhanced erosion resistance of the spray zone. The roads disclosed in 丄々 and α are only examples of the application of the present invention, and are not intended to limit the application of the present invention, and the singularity and refinement of the present invention should not belong to the present invention. The scope of application of the invention is therefore subject to the definition of the scope of the invention. -12- 1253473 [Simple description of the diagram] The first picture: the appearance of the blade of the last stage of the turbine. Fig. 2 is a schematic diagram showing the appearance of the cross-section of the last stage blade after laser spraying. The third figure·The appearance of the cross-section of the final stage of the blade by laser spray treatment. Figure 4: Laser sprayed 17-4 PH stainless steel and H900 aging test piece and transfer type plasma-welded Stellite Νο·6 layer test piece, dry alumina sand (60 mesh) at 30 degree angle The change in weight loss of the blasting test results. [Explanation of main component symbols] 2: Blade base material is not affected by laser heat radiation zone 6: Blade guide end 7: Blade wake end 8: Blade guide end Laser spray treatment zone 9: Blade guide end spray Treatment start point 10: Heat affected zone 11 that is partially dissolved by laser spray treatment: Vertical line perpendicular to the center line of the blade bending moment 12: Blade water droplet or oxide erosion direction 13: Blade bending moment centerline