{"id":113,"date":"2024-10-19T10:48:18","date_gmt":"2024-10-19T10:48:18","guid":{"rendered":"https:\/\/pwhtsolutions.net\/?p=113"},"modified":"2025-01-05T09:25:18","modified_gmt":"2025-01-05T09:25:18","slug":"tepelne-zpracovani-po-svarovani-6","status":"publish","type":"post","link":"https:\/\/pwhtsolutions.net\/cs\/post-weld-heat-treatment-6\/","title":{"rendered":"Tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed"},"content":{"rendered":"

PWHT sni\u017euje zbytkov\u00e1 nap\u011bt\u00ed, zlep\u0161uje mechanick\u00e9 vlastnosti a zvy\u0161uje korozn\u00ed odolnost sva\u0159enc\u016f, co\u017e zvy\u0161uje jejich spolehlivost jako sva\u0159ovan\u00fdch konstrukc\u00ed. P\u0159ed zah\u00e1jen\u00edm o\u0161et\u0159en\u00ed PWHT je v\u0161ak nutn\u00e9 pochopit v\u0161echna jeho omezen\u00ed a potenci\u00e1ln\u00ed nebezpe\u010d\u00ed.<\/p>\n

PWHT (Pressure Wash Heat Treating) je proces zah\u0159\u00edv\u00e1n\u00ed oceli na teplotu, kter\u00e1 je ni\u017e\u0161\u00ed ne\u017e jej\u00ed transforma\u010dn\u00ed rozsah, a jej\u00ed udr\u017eov\u00e1n\u00ed po del\u0161\u00ed dobu. Tento technick\u00fd obor vy\u017eaduje odborn\u00e9 znalosti a vybaven\u00ed.<\/p>\n

\u00daleva od stresu<\/h2>\n

Tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed (PWHT), zn\u00e1m\u00e9 tak\u00e9 jako odstran\u011bn\u00ed nap\u011bt\u00ed po sva\u0159ov\u00e1n\u00ed, sni\u017euje a p\u0159erozd\u011bluje zbytkov\u00e1 nap\u011bt\u00ed ve svarech a z\u00e1rove\u0148 zlep\u0161uje jejich mechanick\u00e9 vlastnosti, jako je ta\u017enost a hou\u017eevnatost. PWHT zahrnuje zah\u0159\u00e1t\u00ed kovu na p\u0159esnou teplotu po del\u0161\u00ed dobu - ta v\u0161ak mus\u00ed z\u016fstat pod teplotou p\u0159em\u011bny, aby nedo\u0161lo k po\u0161kozen\u00ed vlastnost\u00ed materi\u00e1lu.<\/p>\n

Vnit\u0159n\u00ed pnut\u00ed \u010dasto vznikaj\u00ed p\u0159i v\u00fdrobn\u00edch procesech, jako je obr\u00e1b\u011bn\u00ed, lisov\u00e1n\u00ed a sva\u0159ov\u00e1n\u00ed. To vede k deformaci sou\u010d\u00e1st\u00ed, kterou je t\u0159eba odstranit, aby je bylo mo\u017en\u00e9 pou\u017e\u00edvat. PWHT poskytuje mechanismus tepeln\u00e9ho odleh\u010den\u00ed, kter\u00fd m\u016f\u017ee tato pnut\u00ed zm\u00edrnit, ani\u017e by se zm\u011bnily jejich fyzik\u00e1ln\u00ed vlastnosti.<\/p>\n

V\u0161imn\u011bte si, \u017ee proces uvol\u0148ov\u00e1n\u00ed stresu m\u016f\u017ee b\u00fdt ovlivn\u011bn prost\u0159ed\u00edm. Vysok\u00e1 vlhkost nebo p\u016fsoben\u00ed chemik\u00e1li\u00ed m\u016f\u017ee zm\u011bnit proces PWHT a sn\u00ed\u017eit \u00fa\u010dinnost zbytkov\u00e9ho uvol\u0148ov\u00e1n\u00ed nap\u011bt\u00ed, co\u017e zvy\u0161uje riziko selh\u00e1n\u00ed svaru i riziko koroze.<\/p>\n

PWHT nejen sni\u017euje zbytkov\u00e9 nap\u011bt\u00ed, ale m\u016f\u017ee tak\u00e9 chr\u00e1nit p\u0159ed koroz\u00ed. Pokud je kov vystaven sou\u010dasn\u011b nam\u00e1h\u00e1n\u00ed a korozi, m\u016f\u017ee se st\u00e1t n\u00e1chyln\u00fdm ke vzniku korozn\u00edch trhlin v d\u016fsledku nerovnov\u00e1hy mezi tahov\u00fdmi nap\u011bt\u00edmi a pru\u017enou deformac\u00ed struktury materi\u00e1lu. Odleh\u010den\u00ed nap\u011bt\u00ed b\u011bhem PWHT tomu zabr\u00e1n\u00ed t\u00edm, \u017ee sn\u00ed\u017e\u00ed tahov\u00e1 nap\u011bt\u00ed a z\u00e1rove\u0148 zv\u00fd\u0161\u00ed pru\u017enou deformaci, \u010d\u00edm\u017e zcela zabr\u00e1n\u00ed vzniku korozn\u00edch trhlin.<\/p>\n

Mechanick\u00e9 vlastnosti<\/h2>\n

Proto\u017ee p\u0159i sva\u0159ov\u00e1n\u00ed vznikaj\u00ed velk\u00e9 teplotn\u00ed gradienty mezi svarov\u00fdm kovem a z\u00e1kladn\u00edm materi\u00e1lem, mohou zbytkov\u00e1 nap\u011bt\u00ed ve svarov\u00e9m materi\u00e1lu sn\u00ed\u017eit jeho pevnost. Ke zm\u00edrn\u011bn\u00ed t\u011bchto nap\u011bt\u00ed a zlep\u0161en\u00ed mechanick\u00fdch vlastnost\u00ed lze pou\u017e\u00edt tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed (PWHT) - tento proces se b\u011b\u017en\u011b ozna\u010duje jako PWHT.<\/p>\n

PWHT zahrnuje oh\u0159ev sva\u0159ovan\u00e9ho materi\u00e1lu pod jeho ni\u017e\u0161\u00ed kritickou teplotu p\u0159em\u011bny a jeho udr\u017eov\u00e1n\u00ed po stanovenou dobu, obvykle se prov\u00e1d\u00ed u tlakov\u00fdch n\u00e1dob a jin\u00fdch za\u0159\u00edzen\u00ed, kter\u00e1 vy\u017eaduj\u00ed vysokou \u00farove\u0148 bezpe\u010dnosti a spolehlivosti. M\u016f\u017ee pomoci sn\u00ed\u017eit k\u0159ehk\u00e9 lomy ve svarech a z\u00e1rove\u0148 zv\u00fd\u0161it jejich tahov\u00e9 vlastnosti.<\/p>\n

Je v\u0161ak t\u0159eba m\u00edt na pam\u011bti, \u017ee PWHT m\u016f\u017ee tak\u00e9 zhor\u0161it n\u011bkter\u00e9 mechanick\u00e9 vlastnosti, v\u010detn\u011b r\u00e1zov\u00e9 hou\u017eevnatosti a ta\u017enosti svar\u016f, nicm\u00e9n\u011b jej\u00ed v\u00fdhody z\u016fst\u00e1vaj\u00ed zna\u010dn\u00e9.<\/p>\n

Bylo prok\u00e1z\u00e1no, \u017ee PWHT v\u00fdznamn\u011b zlep\u0161uje mechanick\u00e9 vlastnosti sva\u0159ovan\u00fdch NiTi materi\u00e1l\u016f, zejm\u00e9na lokalizaci plastick\u00e9 deformace v hrubozrnn\u00fdch oblastech, jako je HAZ a FZ, potla\u010den\u00edm tvorby dislokac\u00ed a sn\u00ed\u017een\u00edm aktua\u010dn\u00ed deformace v t\u011bchto oblastech; tento \u00fa\u010dinek se p\u0159isuzuje rozpou\u0161t\u011bn\u00ed zpev\u0148uj\u00edc\u00edch g-f\u00e1z\u00ed b\u011bhem PWHT.<\/p>\n

Odolnost proti korozi<\/h2>\n

Tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed (PWHT) nebo tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed je proces prov\u00e1d\u011bn\u00fd po sva\u0159ov\u00e1n\u00ed, kter\u00fd zaji\u0161\u0165uje shodu s pr\u016fmyslov\u00fdmi p\u0159edpisy a specifikacemi a sni\u017euje riziko koroze. Jedn\u00e1 se o ned\u00edln\u00fd krok, kter\u00fd mus\u00ed prob\u011bhnout, pokud maj\u00ed materi\u00e1ly spl\u0148ovat pr\u016fmyslov\u00e9 specifikace a z\u00e1rove\u0148 se proti n\u00ed chr\u00e1nit.<\/p>\n

Tepeln\u00e9 zpracov\u00e1n\u00ed zahrnuje zah\u0159\u00e1t\u00ed svarov\u00e9ho kovu na ur\u010ditou teplotu a jeho pomal\u00e9 ochlazen\u00ed, aby se uvolnila zbytkov\u00e1 nap\u011bt\u00ed vznikl\u00e1 p\u0159i sva\u0159ov\u00e1n\u00ed a zabr\u00e1nilo se vzniku trhlin vyvolan\u00fdch vod\u00edkem (HIC). Krom\u011b toho m\u016f\u017ee toto o\u0161et\u0159en\u00ed zlep\u0161it mechanick\u00e9 vlastnosti vytvo\u0159en\u00edm homogenn\u011bj\u0161\u00edho materi\u00e1lu se sn\u00ed\u017eenou tvrdost\u00ed.<\/p>\n

Normalizace spo\u010d\u00edv\u00e1 v zah\u0159\u00edv\u00e1n\u00ed materi\u00e1lu p\u0159i vy\u0161\u0161\u00edch teplot\u00e1ch po del\u0161\u00ed dobu ne\u017e p\u0159i \u017e\u00edh\u00e1n\u00ed, co\u017e umo\u017e\u0148uje dos\u00e1hnout jemn\u011bj\u0161\u00ed struktury zrn vhodn\u00e9 pro pou\u017eit\u00ed s vy\u0161\u0161\u00ed pevnost\u00ed. Je v\u0161ak t\u0159eba m\u00edt na pam\u011bti, \u017ee n\u011bkter\u00e9 konstrukce nemohou b\u00fdt podrobeny normaliza\u010dn\u00edmu PWHT z d\u016fvodu, \u017ee velk\u00e9 a slo\u017eit\u011b tvarovan\u00e9 sou\u010d\u00e1sti nejsou schopny udr\u017eet se p\u0159i teplot\u011b nam\u00e1\u010den\u00ed; to by pravd\u011bpodobn\u011b zp\u016fsobilo katastrofick\u00e9 prohnut\u00ed a deformaci. Proto by se PWHT m\u011bla prov\u00e1d\u011bt pouze na sou\u010d\u00e1stech, kter\u00e9 lze snadno podep\u0159\u00edt; p\u0159\u00edkladem m\u016f\u017ee b\u00fdt dr\u00e1\u017ekovan\u00fd konec tlakov\u00e9 n\u00e1doby, proto\u017ee tento typ sou\u010d\u00e1sti by byl vynikaj\u00edc\u00edm kandid\u00e1tem pro normaliza\u010dn\u00ed PWHT. PWHT s op\u011btovn\u00fdm rozpou\u0161t\u011bn\u00edm lze pou\u017e\u00edt k rozpu\u0161t\u011bn\u00ed karbid\u016f chromu nach\u00e1zej\u00edc\u00edch se pod\u00e9l hranic zrn mezi delta feritem a austenitem, kter\u00e9 by mohly zhor\u0161it odolnost proti d\u016flkov\u00e9 korozi duplexn\u00ed nerezov\u00e9 oceli (DSS).<\/p>\n

Podm\u00ednky prost\u0159ed\u00ed<\/h2>\n

PWHT je nezbytn\u00fdm krokem p\u0159i navrhov\u00e1n\u00ed a \u00fadr\u017eb\u011b mnoha ocelov\u00fdch konstrukc\u00ed, jako jsou tlakov\u00e9 n\u00e1doby, potrubn\u00ed za\u0159\u00edzen\u00ed, mosty a plo\u0161iny na mo\u0159i. PWHT sni\u017euje prask\u00e1n\u00ed vlivem prost\u0159ed\u00ed t\u00edm, \u017ee sni\u017euje zbytkov\u00e1 nap\u011bt\u00ed ve svarech a popou\u0161t\u00ed mikrostrukturu svarov\u00e9ho kovu, p\u0159i\u010dem\u017e zvy\u0161uje hou\u017eevnatost pro lep\u0161\u00ed odolnost proti zat\u00ed\u017een\u00ed a podm\u00ednk\u00e1m prost\u0159ed\u00ed, kter\u00fdm bude svarov\u00e1 sestava vystavena b\u011bhem sv\u00e9 \u017eivotnosti.<\/p>\n

PWHT je obvykle vy\u017eadov\u00e1na v konstruk\u010dn\u00edch aplikac\u00edch zahrnuj\u00edc\u00edch uhl\u00edkov\u00e9 oceli s tlou\u0161\u0165kou p\u0159esahuj\u00edc\u00ed p\u0159edpisem definovanou mez a n\u00edzkolegovan\u00e9 oceli, aby se sn\u00ed\u017eilo zbytkov\u00e9 nap\u011bt\u00ed zp\u016fsoben\u00e9 sva\u0159ov\u00e1n\u00edm, kter\u00e9 by jinak mohlo v\u00e9st k iniciaci trhlin a p\u0159\u00edpadn\u00e9mu k\u0159ehk\u00e9mu lomu. Proces zahrnuje p\u0159edeh\u0159ev, nam\u00e1\u010den\u00ed, oh\u0159ev na c\u00edlovou teplotu a \u0159\u00edzen\u00e9 chlazen\u00ed, aby se minimalizovaly deformace nebo zbytkov\u00e1 nap\u011bt\u00ed v p\u0159ilehl\u00fdch oblastech svaru.<\/p>\n

Po oprav\u00e1ch a \u00faprav\u00e1ch svar\u016f v tlakov\u00fdch n\u00e1dob\u00e1ch a potrubn\u00edch syst\u00e9mech se \u010dasto pou\u017e\u00edv\u00e1 lok\u00e1ln\u00ed PWHT, jako jsou bodov\u00e9 konfigurace nebo konfigurace s b\u00fd\u010d\u00edmi oky. Pe\u010dliv\u00e9 navrhov\u00e1n\u00ed konfigurac\u00ed lok\u00e1ln\u00ed PWHT je kl\u00ed\u010dem k zabr\u00e1n\u011bn\u00ed deformaci, prask\u00e1n\u00ed a dal\u0161\u00edm po\u0161kozen\u00edm, kter\u00e1 prodlu\u017euj\u00ed dobu odst\u00e1vky opravy; pokro\u010dil\u00e9 tepeln\u011b-mechanick\u00e9 anal\u00fdzy kone\u010dn\u00fdch prvk\u016f konfigurac\u00ed lok\u00e1ln\u00ed PWHT a jejich stav\u016f zbytkov\u00e9ho nap\u011bt\u00ed mohou pomoci dos\u00e1hnout tohoto v\u00fdsledku.<\/p>","protected":false},"excerpt":{"rendered":"

PWHT sni\u017euje zbytkov\u00e1 nap\u011bt\u00ed, zlep\u0161uje mechanick\u00e9 vlastnosti a zvy\u0161uje korozn\u00ed odolnost sva\u0159enc\u016f, co\u017e zvy\u0161uje jejich spolehlivost jako sva\u0159ovan\u00fdch konstrukc\u00ed. P\u0159ed zah\u00e1jen\u00edm o\u0161et\u0159en\u00ed PWHT je v\u0161ak nutn\u00e9 pochopit v\u0161echna jeho omezen\u00ed a potenci\u00e1ln\u00ed nebezpe\u010d\u00ed. PWHT (Pressure Wash Heat Treating) je proces zah\u0159\u00edv\u00e1n\u00ed oceli na teploty, kter\u00e9 jsou ni\u017e\u0161\u00ed ne\u017e jej\u00ed rozsah p\u0159etv\u00e1\u0159en\u00ed a ... <\/p>\n

P\u0159e\u010dt\u011bte si v\u00edce “Post Weld Heat Treatment”<\/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-113","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\/113","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=113"}],"version-history":[{"count":1,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/113\/revisions"}],"predecessor-version":[{"id":114,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/113\/revisions\/114"}],"wp:attachment":[{"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/media?parent=113"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/categories?post=113"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/tags?post=113"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}