{"id":227,"date":"2024-12-25T02:16:38","date_gmt":"2024-12-25T02:16:38","guid":{"rendered":"https:\/\/pwhtsolutions.net\/?p=227"},"modified":"2025-01-05T09:23:03","modified_gmt":"2025-01-05T09:23:03","slug":"tepelne-zpracovani-po-svarovani-pwht-3","status":"publish","type":"post","link":"https:\/\/pwhtsolutions.net\/cs\/post-weld-heat-treatment-pwht-3\/","title":{"rendered":"Tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed (PWHT)"},"content":{"rendered":"

Tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed (PWHT) je ned\u00edlnou sou\u010d\u00e1st\u00ed procesu, kter\u00fd sni\u017euje zbytkov\u00e1 nap\u011bt\u00ed p\u0159i sva\u0159ov\u00e1n\u00ed a minimalizuje k\u0159ehk\u00fd lom. V z\u00e1vislosti na po\u017eadavc\u00edch projektu m\u016f\u017ee b\u00fdt PWHT podle sva\u0159ovac\u00edch p\u0159edpis\u016f a na\u0159\u00edzen\u00ed tak\u00e9 povinn\u00e1.<\/p>\n

Procesy PWHT mohou b\u00fdt \u010dasov\u011b i pracovn\u011b n\u00e1ro\u010dn\u00e9 a vy\u017eaduj\u00ed specializovan\u00e9 vybaven\u00ed a za\u0159\u00edzen\u00ed i p\u0159\u00edsn\u00e1 opat\u0159en\u00ed pro zaji\u0161t\u011bn\u00ed kvality.<\/p>\n

\u017d\u00edh\u00e1n\u00ed<\/h2>\n

\u017d\u00edh\u00e1n\u00ed je jednou z nejpou\u017e\u00edvan\u011bj\u0161\u00edch tepeln\u00fdch \u00faprav. Tato technika spo\u010d\u00edv\u00e1 v zah\u0159\u00e1t\u00ed obrobku na vysokou teplotu a n\u00e1sledn\u00e9m pomal\u00e9m ochlazen\u00ed, co\u017e umo\u017en\u00ed atom\u016fm v kovu zm\u011bnit sv\u00e9 uspo\u0159\u00e1d\u00e1n\u00ed, uvolnit nap\u011bt\u00ed a obnovit ta\u017enost. \u017d\u00edh\u00e1n\u00ed je d\u016fle\u017eit\u00fdm krokem p\u0159i PWHT, kter\u00fd sni\u017euje riziko vzniku trhlin nebo prasklin b\u011bhem n\u00e1sledn\u00fdch mechanick\u00fdch proces\u016f; nav\u00edc je \u010dasto nezbytn\u00e9 pro n\u011bkter\u00e9 projekty v (petro)chemick\u00e9m pr\u016fmyslu, p\u0159i stavb\u011b kotl\u016f a v pob\u0159e\u017en\u00edm pr\u016fmyslu.<\/p>\n

\u017d\u00edh\u00e1n\u00ed m\u016f\u017ee tak\u00e9 zlep\u0161it fyzik\u00e1ln\u00ed vlastnosti tepeln\u011b ovlivn\u011bn\u00fdch z\u00f3n svaru (HAZ). P\u0159i sva\u0159ov\u00e1n\u00ed doch\u00e1z\u00ed k tuhnut\u00ed roztaven\u00fdch materi\u00e1l\u016f na obou stran\u00e1ch svarov\u00e9ho spoje, \u010d\u00edm\u017e vznikaj\u00ed oblasti n\u00e1chyln\u00e9 ke korozi, kter\u00e9 jsou n\u00e1chyln\u00e9 k l\u00e1m\u00e1n\u00ed a k\u0159ehnut\u00ed. Sn\u00ed\u017een\u00edm teploty t\u00e1n\u00ed \u017e\u00edh\u00e1n\u00edm \u017e\u00edh\u00e1n\u00ed tyto probl\u00e9my v\u00fdrazn\u011b omezuje.<\/p>\n

\u017d\u00edh\u00e1n\u00ed na uvoln\u011bn\u00ed nap\u011bt\u00ed se pou\u017e\u00edv\u00e1 ke zm\u00edrn\u011bn\u00ed vnit\u0159n\u00edch pnut\u00ed zp\u016fsoben\u00fdch obr\u00e1b\u011bn\u00edm za studena a tepeln\u00fdm cyklov\u00e1n\u00edm u velk\u00fdch odlitk\u016f, sva\u0159ovan\u00fdch d\u00edl\u016f a kus\u016f tv\u00e1\u0159en\u00fdch za studena. Tato metoda zahrnuje jejich p\u0159esn\u00e9 zah\u0159\u00e1t\u00ed na c\u00edlovou teplotu p\u0159ed zah\u00e1jen\u00edm pomal\u00e9ho ochlazov\u00e1n\u00ed, kter\u00e9 \u0159\u00edd\u00ed rychlost ochlazov\u00e1n\u00ed.<\/p>\n

Rekrystaliza\u010dn\u00ed \u017e\u00edh\u00e1n\u00ed (RCA) je technika, kter\u00e1 podporuje tvorbu nepo\u0161kozen\u00fdch zrn ve struktu\u0159e slitiny jej\u00edm zah\u0159\u00e1t\u00edm nad kritickou teplotu a n\u00e1sledn\u00fdm pomal\u00fdm ochlazov\u00e1n\u00edm, p\u0159i\u010dem\u017e deformovan\u00e1 zrna jsou nahrazena nov\u00fdmi, nedeformovan\u00fdmi, \u010d\u00edm\u017e se sni\u017euje tvrdost kovu a zvy\u0161uje se redukce tvrdosti. Rekrystaliza\u010dn\u00ed \u017e\u00edh\u00e1n\u00ed m\u016f\u017ee tak\u00e9 pomoci zjemnit mikrostrukturu a velikost zrn materi\u00e1l\u016f, \u010d\u00edm\u017e se d\u00e1le sn\u00ed\u017e\u00ed tvrdost a sou\u010dasn\u011b se zjemn\u00ed mikrostruktura.<\/p>\n

Normalizace<\/h2>\n

B\u011bhem sva\u0159ov\u00e1n\u00ed doch\u00e1z\u00ed k teplotn\u00edm gradient\u016fm mezi oblast\u00ed svaru a okoln\u00edm materi\u00e1lem, co\u017e vede k n\u00e1r\u016fstu zbytkov\u00e9ho nap\u011bt\u00ed, kter\u00e9 m\u016f\u017ee v kombinaci s nam\u00e1h\u00e1n\u00edm p\u0159i zat\u00ed\u017een\u00ed zp\u016fsobit selh\u00e1n\u00ed svaru a korozn\u00ed prask\u00e1n\u00ed. PWHT tato zbytkov\u00e1 nap\u011bt\u00ed zm\u00edr\u0148uje, zlep\u0161uje hou\u017eevnatost a ta\u017enost sva\u0159ovan\u00fdch materi\u00e1l\u016f a z\u00e1rove\u0148 zvy\u0161uje jejich odolnost proti prask\u00e1n\u00ed - co\u017e je po\u017eadov\u00e1no ve v\u011bt\u0161in\u011b p\u0159edpis\u016f a specifikac\u00ed pro tlakov\u00e9 n\u00e1doby a potrub\u00ed.<\/p>\n

Normalizace je zp\u016fsob tepeln\u00e9ho zpracov\u00e1n\u00ed, p\u0159i kter\u00e9m se kov zah\u0159eje na kritickou teplotu a pot\u00e9 se ochlad\u00ed na vzduchu, p\u0159i\u010dem\u017e p\u0159i ochlazov\u00e1n\u00ed vznik\u00e1 perlit, martenzit a ferit, co\u017e mu pom\u00e1h\u00e1 zachovat si hou\u017eevnatost i po ochlazen\u00ed a z\u00e1rove\u0148 sni\u017euje deformace a zvy\u0161uje pevnost. Normalizace se doporu\u010duje zejm\u00e9na u ocel\u00ed vystaven\u00fdch vysok\u00e9mu obsahu soli nebo pov\u011btrnostn\u00edm vliv\u016fm, proto\u017ee je chr\u00e1n\u00ed p\u0159ed korozn\u00edm prask\u00e1n\u00edm.<\/p>\n

PWHT z\u00e1vis\u00ed na n\u011bkolika faktorech, v\u010detn\u011b chemick\u00e9ho slo\u017een\u00ed a tlou\u0161\u0165ky materi\u00e1lu. N\u011bkter\u00e9 p\u0159edpisy ji vy\u017eaduj\u00ed pouze v p\u0159\u00edpad\u011b, \u017ee tlou\u0161\u0165ka p\u0159es\u00e1hne stanovenou hodnotu; v jin\u00fdch p\u0159\u00edpadech je nutn\u00e1 kv\u016fli n\u00e1chylnosti materi\u00e1lu k prask\u00e1n\u00ed vyvolan\u00e9mu vod\u00edkem; lok\u00e1ln\u00ed tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed lze \u010dasto prov\u00e9st zah\u0159\u00e1t\u00edm prstencov\u00e9ho p\u00e1su obklopuj\u00edc\u00edho svarov\u00fd spoj.<\/p>\n

\u0158\u00edzen\u00ed teploty<\/h2>\n

V pr\u016fb\u011bhu sva\u0159ov\u00e1n\u00ed vznikaj\u00ed mezi svarem a z\u00e1kladn\u00edm materi\u00e1lem teplotn\u00ed gradienty, kter\u00e9 mohou nar\u016fst na nep\u0159ijatelnou \u00farove\u0148 a v\u00e9st k vod\u00edkem indukovan\u00e9mu prask\u00e1n\u00ed (HIC) nebo korozn\u00edmu prask\u00e1n\u00ed (SCC). PWHT m\u016f\u017ee pomoci zm\u00edrnit tato nap\u011bt\u00ed a zv\u00fd\u0161it korozn\u00ed odolnost sva\u0159ovan\u00fdch sou\u010d\u00e1st\u00ed.<\/p>\n

PWHT zahrnuje zah\u0159\u00edv\u00e1n\u00ed sva\u0159ovan\u00e9ho materi\u00e1lu na teploty ni\u017e\u0161\u00ed, ne\u017e je jeho po\u010d\u00e1te\u010dn\u00ed teplota p\u0159em\u011bny, a jeho postupn\u00e9 ochlazov\u00e1n\u00ed s c\u00edlem uvolnit vnit\u0159n\u00ed pnut\u00ed a vytvo\u0159it homogenn\u011bj\u0161\u00ed strukturu kovu p\u0159i sou\u010dasn\u00e9m sn\u00ed\u017een\u00ed tvrdosti a zlep\u0161en\u00ed mechanick\u00fdch vlastnost\u00ed.<\/p>\n

Je t\u0159eba v\u011bnovat pozornost nastaven\u00ed a kontrole teplotn\u00edch toleranc\u00ed PWHT, doby p\u0159i teplot\u011b a rychlosti oh\u0159evu, aby se minimalizovaly nep\u0159\u00edzniv\u00e9 \u00fa\u010dinky, jako je k\u0159ehnut\u00ed, p\u0159\u00edli\u0161n\u00e9 m\u011bknut\u00ed, prask\u00e1n\u00ed p\u0159i op\u011btovn\u00e9m oh\u0159evu a deformace. Teploty PWHT nav\u00edc nesm\u00ed p\u0159ekro\u010dit limity uveden\u00e9 v kvalifika\u010dn\u00edch specifikac\u00edch sva\u0159ovac\u00edho postupu.<\/p>\n

PWHT m\u016f\u017ee b\u00fdt slo\u017eitou a \u010dasov\u011b n\u00e1ro\u010dnou sou\u010d\u00e1st\u00ed sva\u0159ovac\u00edho procesu, co\u017e zvy\u0161uje slo\u017eitost i n\u00e1klady na \u010dasov\u00fd pl\u00e1n a n\u00e1klady projektu. P\u0159esto\u017ee je obt\u00ed\u017en\u00e9 jej kontrolovat a vy\u017eaduje vysokou \u00farove\u0148 dovednost\u00ed pro dosa\u017een\u00ed optim\u00e1ln\u00edch v\u00fdsledk\u016f, nedostate\u010dn\u00e9 monitorov\u00e1n\u00ed nebo kontrola kvality by mohly v\u00e9st k nekvalitn\u00edm v\u00fdsledk\u016fm, co\u017e by d\u00e1le zv\u00fd\u0161ilo n\u00e1klady a \u010dasov\u00fd harmonogram. Opakovan\u00e9 cykly oh\u0159evu\/chlazen\u00ed mohou nav\u00edc u n\u011bkter\u00fdch slitin zp\u016fsobit tepelnou \u00fanavu, kter\u00e1 v\u00fdrazn\u011b zkracuje jejich \u017eivotnost; 6z\u00f3nov\u00fd regul\u00e1tor teploty Ramp\/Soak PWHT spole\u010dnosti Libratherm m\u016f\u017ee pomoci tyto obavy zm\u00edrnit udr\u017eov\u00e1n\u00edm vhodn\u00fdch teplot v pr\u016fb\u011bhu cel\u00e9ho procesu tepeln\u00e9ho zpracov\u00e1n\u00ed.<\/p>\n

Monitorov\u00e1n\u00ed<\/h2>\n

Monitorov\u00e1n\u00ed je ned\u00edlnou sou\u010d\u00e1st\u00ed ka\u017ed\u00e9 intervence, projektu nebo politiky. Pom\u00e1h\u00e1 identifikovat probl\u00e9my a informovat o rozhodov\u00e1n\u00ed a z\u00e1rove\u0148 zaji\u0161\u0165uje, \u017ee intervence jsou prov\u00e1d\u011bny spr\u00e1vn\u011b a dosahuj\u00ed po\u017eadovan\u00fdch v\u00fdsledk\u016f. Monitorov\u00e1n\u00ed vy\u017eaduje shroma\u017e\u010fov\u00e1n\u00ed \u00fadaj\u016f po celou dobu trv\u00e1n\u00ed programu nebo politiky, aby se zajistila jejich \u00fasp\u011b\u0161nost.<\/p>\n

Mont\u00e1\u017e m\u016f\u017ee b\u00fdt u rozs\u00e1hl\u00fdch projekt\u016f vy\u010derp\u00e1vaj\u00edc\u00ed a \u010dasov\u011b n\u00e1ro\u010dn\u00e1. N\u00e1ro\u010dn\u00e9 m\u016f\u017ee b\u00fdt i nalezen\u00ed vy\u0161kolen\u00e9ho person\u00e1lu, kter\u00fd by tento proces \u0159\u00eddil. Krom\u011b toho mohou cykly zah\u0159\u00edv\u00e1n\u00ed a chlazen\u00ed po\u0161kodit n\u011bkter\u00e9 materi\u00e1ly, pokud nejsou kontrolov\u00e1ny; to by mohlo zp\u016fsobit deformaci nebo pok\u0159iven\u00ed sva\u0159ovan\u00fdch sou\u010d\u00e1st\u00ed, ovlivnit jejich rozm\u011brovou p\u0159esnost nebo struktur\u00e1ln\u00ed integritu a vy\u017eadovat dal\u0161\u00ed kontroly a opravy pro obnoven\u00ed spr\u00e1vn\u00e9 funkce za\u0159\u00edzen\u00ed.<\/p>\n

Postupy PWHT mohou pomoci zm\u00edrnit tyto probl\u00e9my a minimalizovat riziko poruch tlakov\u00fdch za\u0159\u00edzen\u00ed t\u00edm, \u017ee zvy\u0161uj\u00ed odolnost proti korozn\u00edmu prask\u00e1n\u00ed, sni\u017euj\u00ed riziko deformace a prodlu\u017euj\u00ed \u017eivotnost za\u0159\u00edzen\u00ed. O\u0161et\u0159en\u00ed PWHT je nezbytn\u00e9 v potrub\u00edch, jadern\u00fdch elektr\u00e1rn\u00e1ch a dal\u0161\u00edch prost\u0159ed\u00edch, kde jsou sva\u0159ovan\u00e9 materi\u00e1ly vystaveny vysok\u00fdm teplot\u00e1m a prost\u0159ed\u00ed bohat\u00e9mu na korozi - v\u010detn\u011b ropovod\u016f a plynovod\u016f, jadern\u00fdch elektr\u00e1ren a mnoha aplikac\u00ed, kde mohou b\u00fdt sva\u0159ovan\u00e9 materi\u00e1ly vystaveny vysok\u00fdm teplot\u00e1m a prost\u0159ed\u00ed bohat\u00e9mu na korozi - nap\u0159\u00edklad ropovody a plynovody, kotle a za\u0159\u00edzen\u00ed stroj\u00edrensk\u00e9 v\u00fdroby na mo\u0159i. Mnoh\u00e1 pr\u016fmyslov\u00e1 odv\u011btv\u00ed vyu\u017e\u00edvaj\u00ed PWHT podle v\u00fdrobn\u00edch standard\u016f; p\u0159\u00edklady zahrnuj\u00ed v\u00fdroby v ropn\u00e9m a plyn\u00e1rensk\u00e9m pr\u016fmyslu, kter\u00e9 vyu\u017e\u00edvaj\u00ed postupy PWHT, v\u010detn\u011b v\u00fdrob v ropn\u00e9m a plyn\u00e1rensk\u00e9m pr\u016fmyslu, zat\u00edmco jin\u00e9 vyu\u017e\u00edvaj\u00ed specifick\u00e9 normy vy\u017eaduj\u00edc\u00ed jej\u00ed zahrnut\u00ed do v\u00fdrob, jako je ropn\u00fd a plyn\u00e1rensk\u00fd pr\u016fmysl, kter\u00fd vyu\u017e\u00edv\u00e1 v\u00fdrobn\u00ed standardy PWHT, kter\u00e9 mus\u00ed vyu\u017e\u00edvat PWHT p\u0159i v\u00fdrob\u011b sva\u0159ovan\u00fdch sou\u010d\u00e1st\u00ed materi\u00e1l\u016f, jako jsou kotle a za\u0159\u00edzen\u00ed leteck\u00e9ho pr\u016fmyslu, stroj\u00edrensk\u00e9 v\u00fdroby atd. ec t v\u00fdroby atd. vy\u017eaduj\u00edc\u00ed v\u00fdrobu PWHT, jako jsou kotle a za\u0159\u00edzen\u00ed leteck\u00e9ho pr\u016fmyslu, stroj\u00edrensk\u00e9 kotle a offshore.<\/p>","protected":false},"excerpt":{"rendered":"

Tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed (PWHT) je ned\u00edlnou sou\u010d\u00e1st\u00ed procesu, kter\u00fd sni\u017euje zbytkov\u00e1 nap\u011bt\u00ed p\u0159i sva\u0159ov\u00e1n\u00ed a minimalizuje k\u0159ehk\u00fd lom. V z\u00e1vislosti na po\u017eadavc\u00edch projektu m\u016f\u017ee b\u00fdt PWHT podle sva\u0159ovac\u00edch p\u0159edpis\u016f a na\u0159\u00edzen\u00ed tak\u00e9 povinn\u00e1. Procesy PWHT mohou b\u00fdt \u010dasov\u011b i pracovn\u011b n\u00e1ro\u010dn\u00e9 a vy\u017eaduj\u00ed specializovan\u00e9 vybaven\u00ed a za\u0159\u00edzen\u00ed i p\u0159\u00edsn\u00e1 opat\u0159en\u00ed pro zaji\u0161t\u011bn\u00ed kvality. \u017d\u00edh\u00e1n\u00ed \u017d\u00edh\u00e1n\u00ed je ... <\/p>\n

P\u0159e\u010dt\u011bte si v\u00edce “Post-Weld Heat Treatment (PWHT)”<\/span><\/a><\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-227","post","type-post","status-publish","format-standard","hentry","category-product-related"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/227","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/comments?post=227"}],"version-history":[{"count":1,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/227\/revisions"}],"predecessor-version":[{"id":228,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/227\/revisions\/228"}],"wp:attachment":[{"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/media?parent=227"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/categories?post=227"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/tags?post=227"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}