{"id":277,"date":"2025-08-28T10:10:05","date_gmt":"2025-08-28T10:10:05","guid":{"rendered":"https:\/\/pwhtsolutions.net\/?p=277"},"modified":"2025-08-28T10:10:06","modified_gmt":"2025-08-28T10:10:06","slug":"pozadavky-pwht-na-materialy-pouzivane-v-zarizenich-navrzenych-podle-oddilu-asme-viii-divize-1","status":"publish","type":"post","link":"http:\/\/pwhtsolutions.net\/cs\/pwht-requirements-for-materials-used-in-equipment-designed-to-asme-section-viii-div-1\/","title":{"rendered":"Po\u017eadavky na PWHT pro materi\u00e1ly pou\u017e\u00edvan\u00e9 v za\u0159\u00edzen\u00edch navr\u017een\u00fdch podle ASME, odd\u00edl VIII, divize 1"},"content":{"rendered":"

UCS-56-1 a\u017e UCS-56-11 tabulky UCS-561 stanov\u00ed po\u017eadavky a v\u00fdjimky pro materi\u00e1ly pou\u017e\u00edvan\u00e9 v za\u0159\u00edzen\u00edch navr\u017een\u00fdch podle ASME, odd\u00edl VIII, divize 1. V t\u011bchto tabulk\u00e1ch jsou rovn\u011b\u017e uvedeny v\u00fdjimky.<\/p>\n

PWHT (Powder Waste Heat Treatment) je \u0159\u00edzen\u00fd proces, p\u0159i kter\u00e9m jsou materi\u00e1ly po del\u0161\u00ed dobu zah\u0159\u00edv\u00e1ny nad jejich ni\u017e\u0161\u00ed kritickou teplotu p\u0159em\u011bny, aby se zm\u00edrnila zbytkov\u00e1 nap\u011bt\u00ed a zv\u00fd\u0161ila hou\u017eevnatost svarov\u00e9ho kovu.<\/p>\n

Po\u017eadavky na PWHT<\/h2>\n

Po\u017eadavky na PWHT pro trubkov\u00e9 materi\u00e1ly se v r\u016fzn\u00fdch p\u0159edpisech li\u0161\u00ed, p\u0159i\u010dem\u017e konkr\u00e9tn\u00ed v\u00fdjimky pravd\u011bpodobn\u011b vych\u00e1zej\u00ed z tradi\u010dn\u00edch postup\u016f v konkr\u00e9tn\u00edch pr\u016fmyslov\u00fdch odv\u011btv\u00edch, nikoli z konkr\u00e9tn\u00edch metalurgick\u00fdch nebo konstruk\u010dn\u00edch hledisek.<\/p>\n

P\u0159esto\u017ee se po\u017eadavky na PWHT v r\u016fzn\u00fdch p\u0159edpisech li\u0161\u00ed, je pravd\u011bpodobn\u00e9, \u017ee by bylo mo\u017en\u00e9 stanovit jednotn\u00fd po\u017eadavek na slo\u017een\u00ed oceli - co\u017e by vedlo k jednotn\u011bj\u0161\u00ed v\u00fdrob\u011b v r\u016fzn\u00fdch odv\u011btv\u00edch. Sou\u010dasn\u00e9 p\u0159edpisy uv\u00e1d\u011bj\u00ed teplotn\u00ed rozsahy zalo\u017een\u00e9 na \u010d\u00edslech skupin a P-\u010d\u00edslech jednotliv\u00fdch slo\u017een\u00ed oceli jako rozhoduj\u00edc\u00ed krit\u00e9ria pro po\u017eadavky na PWHT.<\/p>\n

Sou\u010dasn\u00e9 po\u017eadavky na PWHT vych\u00e1zej\u00ed z p\u0159edpokladu, \u017ee teploty p\u0159edeh\u0159evu popou\u0161t\u011bj\u00ed mikrostrukturu svarov\u00e9ho spoje a rozptyluj\u00ed vod\u00edk (11). Zkou\u0161ky proveden\u00e9 organizac\u00ed EPRI v\u0161ak prok\u00e1zaly, \u017ee teploty PWHT pou\u017e\u00edvan\u00e9 v petrochemick\u00fdch aplikac\u00edch t\u011bchto c\u00edl\u016f nedosahuj\u00ed, proto\u017ee vy\u0161\u0161\u00ed teploty p\u0159edeh\u0159evu zp\u016fsobuj\u00ed ne\u017e\u00e1douc\u00ed zm\u011bny r\u00e1zov\u00e9 pevnosti a ta\u017enosti; nav\u00edc sou\u010dasn\u00e1 omezen\u00ed p\u0159edpis\u016f vylu\u010duj\u00ed pou\u017eit\u00ed n\u00edzkolegovan\u00fdch ocel\u00ed pro aplikace v energetice.<\/p>\n

V\u00fdjimky<\/h2>\n

P\u0159edpis ASME nab\u00edz\u00ed ur\u010dit\u00e9 v\u00fdjimky z po\u017eadavk\u016f na r\u00e1zov\u00e9 zkou\u0161ky pro uhl\u00edkov\u00e9 a n\u00edzkolegovan\u00e9 oceli. Vyu\u017eit\u00edm t\u011bchto v\u00fdjimek se m\u016f\u017eete vyhnout n\u00e1klad\u016fm na tyto zkou\u0161ky.<\/p>\n

Chcete-li zjistit, zda m\u00e1te n\u00e1rok na v\u00fdjimku z tabulky UCS-66 normy ASME VIII Div 1, pod\u00edvejte se na obr\u00e1zek UCS-66 a najd\u011bte m\u00edsto, kde se va\u0161e MOC nach\u00e1z\u00ed na k\u0159ivce a kde se setk\u00e1v\u00e1 s teplotou -20 stup\u0148\u016f F - pokud tento pr\u016fse\u010d\u00edk le\u017e\u00ed nad k\u0159ivkou D, m\u016f\u017ee b\u00fdt ud\u011blena v\u00fdjimka z n\u00e1razov\u00fdch zkou\u0161ek.<\/p>\n

Vzhledem k tomu, \u017ee p\u0159i v\u00fdrob\u011b tlakov\u00fdch n\u00e1dob a kotl\u016f se pou\u017e\u00edvaj\u00ed obloukov\u00e9 sva\u0159ovac\u00ed procesy, p\u0159i nich\u017e jsou uhl\u00edkov\u00e9 a n\u00edzkolegovan\u00e9 materi\u00e1ly vystaveny teplot\u00e1m pod bodem mrazu, m\u016f\u017ee u kombinac\u00ed uhl\u00edku a n\u00edzkolegovan\u00fdch materi\u00e1l\u016f doj\u00edt ke ztr\u00e1t\u011b ta\u017enosti zp\u016fsoben\u00e9 zbytkov\u00fdm nap\u011bt\u00edm ve svaru, kter\u00e9 m\u00e1 za n\u00e1sledek k\u0159ehk\u00fd lom. Pro zm\u00edrn\u011bn\u00ed t\u011bchto poruch nab\u00edz\u00ed p\u0159edpis v\u00fdjimky pro n\u00e1razov\u00e9 zkou\u0161ky zalo\u017een\u00e9 na chladn\u011bj\u0161\u00edch kombinac\u00edch MDMT a tlou\u0161\u0165ky, u nich\u017e je m\u00e9n\u011b pravd\u011bpodobn\u00e9, \u017ee dojde k takov\u00fdm ztr\u00e1t\u00e1m ta\u017enosti v d\u016fsledku zbytkov\u00e9ho nap\u011bt\u00ed ve svaru.<\/p>\n

Teploty p\u0159edeh\u0159evu<\/h2>\n

Po\u017eadavky na teplotu p\u0159edeh\u0159evu z\u00e1vis\u00ed na sva\u0159ovan\u00e9m materi\u00e1lu, sva\u0159ovac\u00edch p\u0159edpisech a po\u017eadovan\u00e9m pou\u017eit\u00ed. Je d\u016fle\u017eit\u00e9 pochopit, co to znamen\u00e1 pro v\u00e1\u0161 projekt: Teploty p\u0159edeh\u0159evu zaji\u0161\u0165uj\u00ed ide\u00e1ln\u00ed tepeln\u00e9 podm\u00ednky pro sva\u0159ov\u00e1n\u00ed t\u00edm, \u017ee sni\u017euj\u00ed smr\u0161\u0165ovac\u00ed nap\u011bt\u00ed ve svaru a tepeln\u011b ovlivn\u011bn\u00fdch z\u00f3n\u00e1ch (HAZ), sni\u017euj\u00ed cykly tvorby\/rozptylu vod\u00edku, zvy\u0161uj\u00ed hou\u017eevnatost svarov\u00e9ho kovu a sni\u017euj\u00ed deformace zp\u016fsoben\u00e9 tepeln\u00fdm \u0161okem.<\/p>\n

Sva\u0159ovac\u00ed p\u0159edpisy stanovuj\u00ed minim\u00e1ln\u00ed teploty mezi pr\u016fchody, aby se kontroloval v\u00fdvoj mikrostruktury svarov\u00e9ho kovu a zaru\u010dilo se, \u017ee v\u00fdsledn\u00e9 svary odpov\u00eddaj\u00ed t\u011bm, kter\u00e9 byly vytvo\u0159eny b\u011bhem kvalifikace postupu.<\/p>\n

M\u00edstn\u00ed tepeln\u00e9 \u00fapravy po sva\u0159ov\u00e1n\u00ed nemus\u00ed b\u00fdt nutn\u00e9, pokud jsou svary provedeny podle teploty p\u0159edeh\u0159evu a sva\u0159ovac\u00ed proces pokra\u010duje bez p\u0159eru\u0161en\u00ed, nap\u0159\u00edklad dr\u00e1\u017ekov\u00e9 a koutov\u00e9 svary o \u0161\u00ed\u0159ce men\u0161\u00ed ne\u017e 1\/2 a tlou\u0161\u0165ce 11\/4. Krom\u011b toho mohou b\u00fdt m\u00edstn\u00ed dodate\u010dn\u00e9 tepeln\u00e9 \u00fapravy po sva\u0159ov\u00e1n\u00ed zbyte\u010dn\u00e9 u v\u00edcepr\u016fchodov\u00fdch sva\u0159ovac\u00edch technik.<\/p>\n

Doba p\u0159edeh\u0159evu<\/h2>\n

Pokud pl\u00e1nujete va\u0159it n\u011bco, co vy\u017eaduje del\u0161\u00ed dobu p\u0159\u00edpravy, nap\u0159\u00edklad lasagne nebo kr\u016ftu, je nutn\u00e9 troubu p\u0159edeh\u0159\u00e1t. T\u00edm zajist\u00edte, \u017ee se pokrm uva\u0159\u00ed rovnom\u011brn\u011b, ani\u017e by se p\u0159eh\u0159\u00e1l. N\u011bkter\u00e9 recepty nemus\u00ed p\u0159edeh\u0159\u00e1t\u00ed vy\u017eadovat; v\u017edy se p\u0159edem pora\u010fte s receptem!<\/p>\n

P\u0159edpis ASME, odd\u00edl VIII, divize 1, poskytuje soubor vzorc\u016f a pravidel odvozen\u00fdch z pr\u016fmyslov\u00fdch zku\u0161enost\u00ed, kter\u00e9 poskytuj\u00ed vod\u00edtko pro navrhov\u00e1n\u00ed tlou\u0161t\u011bk tlakov\u00fdch n\u00e1dob s maxim\u00e1ln\u00ed opatrnost\u00ed a d\u016frazem na bezpe\u010dnost. V\u00fdsledkem jsou vysoce konzervativn\u00ed n\u00e1vrhy s vynikaj\u00edc\u00ed \u00farovn\u00ed bezpe\u010dnosti.<\/p>\n

Po\u017eadavky na teplotu p\u0159edeh\u0159evu a dobu udr\u017eov\u00e1n\u00ed (PWHT) se v jednotliv\u00fdch p\u0159edpisech m\u00edrn\u011b li\u0161\u00ed, ale v podstat\u011b z\u016fst\u00e1vaj\u00ed podobn\u00e9. Nap\u0159\u00edklad v\u011bt\u0161ina n\u00edzkolegovan\u00fdch ocel\u00ed vy\u017eaduje o\u0161et\u0159en\u00ed PWHT, a\u010dkoli n\u011bkter\u00e9 oceli pou\u017e\u00edvan\u00e9 v potrubn\u00edch aplikac\u00edch ho nepot\u0159ebuj\u00ed. Rovn\u011b\u017e existuj\u00ed r\u016fzn\u00e9 po\u017eadavky na sva\u0159ence k netlakov\u00fdm d\u00edl\u016fm a na spoje nebo sva\u0159ence s netlakov\u00fdmi d\u00edly; proto je d\u016fle\u017eit\u00e9 porozum\u011bt po\u017eadavk\u016fm na PWHT a doby udr\u017eov\u00e1n\u00ed v jednotliv\u00fdch p\u0159edpisech.<\/p>","protected":false},"excerpt":{"rendered":"

UCS-56-1 a\u017e UCS-56-11 tabulky UCS-561 stanov\u00ed po\u017eadavky a v\u00fdjimky pro materi\u00e1ly pou\u017e\u00edvan\u00e9 v za\u0159\u00edzen\u00edch navr\u017een\u00fdch podle ASME, odd\u00edl VIII, divize 1. V t\u011bchto tabulk\u00e1ch jsou rovn\u011b\u017e uvedeny v\u00fdjimky. PWHT (Powder Waste Heat Treatment) je \u0159\u00edzen\u00fd proces, p\u0159i kter\u00e9m se materi\u00e1ly zah\u0159\u00edvaj\u00ed nad jejich ni\u017e\u0161\u00ed kritickou teplotu p\u0159em\u011bny po del\u0161\u00ed dobu, aby se zm\u00edrnily ... <\/p>\n

P\u0159e\u010dt\u011bte si v\u00edce “PWHT Requirements for Materials Used in Equipment Designed to ASME Section VIII Div 1”<\/span><\/a><\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-277","post","type-post","status-publish","format-standard","hentry","category-pwht-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/277","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/comments?post=277"}],"version-history":[{"count":1,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/277\/revisions"}],"predecessor-version":[{"id":278,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/277\/revisions\/278"}],"wp:attachment":[{"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/media?parent=277"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/categories?post=277"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/tags?post=277"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}