{"title":"不锈钢动力锅炉蒸汽减温器故障","authors":"D. G. Chakrapani","doi":"10.31399/asm.fach.power.c9001566","DOIUrl":null,"url":null,"abstract":"\n A desuperheater diffuser nozzle in the steam supply line failed within nine months of service in an 8.25 MN/sq m (1200 psig) steam line. The nozzle was an austenitic stainless steel casting in conformance to material. The nozzle had numerous cracks on the inside and outside surfaces, and the cracks had penetrated through the wall thickness in several areas. The fracture surfaces had distinct beach markings delineating the crack front, representative of crack propagation stages. The cracks were transgranular and, unlike classical corrosion-fatigue cracks, exhibited branching, characteristic of chloride-induced SCC in austenitic stainless steels. The failure resulted from chloride-induced SCC, possibly assisted by cyclic stress. The recommendation for alternate material for the desuperheater nozzle included nickel base alloys per ASTM B 564, Grades 600 or 800 titanium alloy per ASTM B 367, Grades C3/C4, or ferritic stainless steel alloy per ASTM 182, Grade FXM27.","PeriodicalId":107406,"journal":{"name":"ASM Failure Analysis Case Histories: Power Generating Equipment","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Failure of a Stainless Steel Power Boiler Steam Desuperheater\",\"authors\":\"D. G. Chakrapani\",\"doi\":\"10.31399/asm.fach.power.c9001566\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"\\n A desuperheater diffuser nozzle in the steam supply line failed within nine months of service in an 8.25 MN/sq m (1200 psig) steam line. The nozzle was an austenitic stainless steel casting in conformance to material. The nozzle had numerous cracks on the inside and outside surfaces, and the cracks had penetrated through the wall thickness in several areas. The fracture surfaces had distinct beach markings delineating the crack front, representative of crack propagation stages. The cracks were transgranular and, unlike classical corrosion-fatigue cracks, exhibited branching, characteristic of chloride-induced SCC in austenitic stainless steels. The failure resulted from chloride-induced SCC, possibly assisted by cyclic stress. The recommendation for alternate material for the desuperheater nozzle included nickel base alloys per ASTM B 564, Grades 600 or 800 titanium alloy per ASTM B 367, Grades C3/C4, or ferritic stainless steel alloy per ASTM 182, Grade FXM27.\",\"PeriodicalId\":107406,\"journal\":{\"name\":\"ASM Failure Analysis Case Histories: Power Generating Equipment\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2019-06-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"ASM Failure Analysis Case Histories: Power Generating Equipment\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.31399/asm.fach.power.c9001566\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"ASM Failure Analysis Case Histories: Power Generating Equipment","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.31399/asm.fach.power.c9001566","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
摘要
在8.25 MN/ m2 (1200 psig)蒸汽管线中，蒸汽供应管线中的减温器扩散器喷嘴在使用9个月内发生故障。喷嘴为符合材料要求的奥氏体不锈钢铸件。喷管内外表面均有大量裂纹，裂纹已在多个区域穿透壁厚。断裂面有明显的滩纹，描绘了裂缝前缘，代表了裂缝的扩展阶段。与经典的腐蚀疲劳裂纹不同，这些裂纹是穿晶的，表现出分支，这是奥氏体不锈钢中氯化物诱发SCC的特征。破坏是由氯化物引起的SCC引起的，可能是由循环应力引起的。推荐用于减温器喷嘴的替代材料包括符合ASTM B 564标准的镍基合金，符合ASTM B 367标准的600或800级钛合金，C3/C4级或符合ASTM 182标准的铁素体不锈钢合金，FXM27级。
Failure of a Stainless Steel Power Boiler Steam Desuperheater
A desuperheater diffuser nozzle in the steam supply line failed within nine months of service in an 8.25 MN/sq m (1200 psig) steam line. The nozzle was an austenitic stainless steel casting in conformance to material. The nozzle had numerous cracks on the inside and outside surfaces, and the cracks had penetrated through the wall thickness in several areas. The fracture surfaces had distinct beach markings delineating the crack front, representative of crack propagation stages. The cracks were transgranular and, unlike classical corrosion-fatigue cracks, exhibited branching, characteristic of chloride-induced SCC in austenitic stainless steels. The failure resulted from chloride-induced SCC, possibly assisted by cyclic stress. The recommendation for alternate material for the desuperheater nozzle included nickel base alloys per ASTM B 564, Grades 600 or 800 titanium alloy per ASTM B 367, Grades C3/C4, or ferritic stainless steel alloy per ASTM 182, Grade FXM27.
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