{"id":750,"date":"2019-01-17T01:41:50","date_gmt":"2019-01-17T01:41:50","guid":{"rendered":"http:\/\/johnbrear-plantintegrity.com\/?page_id=750"},"modified":"2019-01-17T01:43:56","modified_gmt":"2019-01-17T01:43:56","slug":"determining-the-cause-of-defects-in-ip-shrouds","status":"publish","type":"page","link":"https:\/\/johnbrear-plantintegrity.com\/?page_id=750","title":{"rendered":"Determining the cause of defects in IP shrouds"},"content":{"rendered":"<p><strong><figure id=\"attachment_751\" aria-describedby=\"caption-attachment-751\" style=\"width: 300px\" class=\"wp-caption alignright\"><img fetchpriority=\"high\" decoding=\"async\" src=\"http:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/Shroud-crack.jpg\" alt=\"\" width=\"300\" height=\"270\" class=\"size-full wp-image-751\" srcset=\"https:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/Shroud-crack.jpg 396w, https:\/\/johnbrear-plantintegrity.com\/wp-content\/uploads\/2019\/01\/Shroud-crack-300x270.jpg 300w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><figcaption id=\"caption-attachment-751\" class=\"wp-caption-text\">Crack in shroud<\/figcaption><\/figure>Component:<\/strong><\/p>\r\n<ul>\r\n    <li>LP steam turbine shrouds; 250MW unit at a power station in the  far east<\/li>\r\n<\/ul>\r\n<p><strong>Problem:<\/strong><\/p>\r\n<ul>\r\n    <li>Through cracks, attributed by the OEM to a 20degC steam temperature change caused by poor reheat control by the operator<\/li>\r\n<\/ul>\r\n<p><strong>Approach:<\/strong><\/p>\r\n<ul>\r\n    <li>An independent assessment involving fractography and stress analysis<\/li>\r\n<\/ul>\r\n<p><strong>Benefits:<\/strong><\/p>\r\n<ul>\r\n    <li>Defect morphology found to be indicative of high-cycle fatigue, rather than the low-cycle fatigue expected to result from temperature fluctuations<\/li>\r\n    <li>The thermal stresses caused by the temperature fluctuations demonstrated to be insufficient to initiate the observed defects, nor grow them through the shroud in the available timescale<\/li>\r\n    <li>A small design change leading to a blade passing problem identified as a plausible cause of high-cycle fatigue<\/li>\r\n<\/ul>\r\n<p><strong>Published:<\/strong><\/p>\r\n<p>Wood, M.I., Jones, G.T., Jarvis, P. \u201cMechanical behaviour of shrouding in the low pressure stage of a 250 MW unit\u201d, 3rd International Charles Parsons Turbine Conference, Newcastle, UK, 25-28th April 1995<\/p>","protected":false},"excerpt":{"rendered":"<p>Component: LP steam turbine shrouds; 250MW unit at a power station in the far east Problem: Through cracks, attributed by the OEM to a 20degC steam temperature change caused by poor reheat control by the operator Approach: An independent assessment involving fractography and stress analysis Benefits: Defect morphology found to be indicative of high-cycle fatigue, &hellip; <a href=\"https:\/\/johnbrear-plantintegrity.com\/?page_id=750\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Determining the cause of defects in IP shrouds<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":169,"menu_order":5,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-750","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages\/750","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=750"}],"version-history":[{"count":4,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages\/750\/revisions"}],"predecessor-version":[{"id":755,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages\/750\/revisions\/755"}],"up":[{"embeddable":true,"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=\/wp\/v2\/pages\/169"}],"wp:attachment":[{"href":"https:\/\/johnbrear-plantintegrity.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=750"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}