{"id":281,"date":"2025-08-30T21:44:01","date_gmt":"2025-08-30T21:44:01","guid":{"rendered":"https:\/\/pwhtsolutions.net\/?p=281"},"modified":"2025-08-30T21:44:02","modified_gmt":"2025-08-30T21:44:02","slug":"co-je-tepelne-zpracovani-po-svarovani-4","status":"publish","type":"post","link":"http:\/\/pwhtsolutions.net\/cs\/what-is-post-weld-heat-treatment-4\/","title":{"rendered":"Co je tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed?"},"content":{"rendered":"

Tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed (PWHT), \u010dast\u011bji ozna\u010dovan\u00e9 zkratkou PWHT, sni\u017euje a p\u0159erozd\u011bluje zbytkov\u00e1 nap\u011bt\u00ed vznikl\u00e1 p\u0159i sva\u0159ov\u00e1n\u00ed. PWHT je z\u00e1sadn\u00edm krokem p\u0159i p\u0159\u00edprav\u011b materi\u00e1l\u016f na celo\u017eivotn\u00ed pou\u017e\u00edv\u00e1n\u00ed v n\u00e1ro\u010dn\u00fdch z\u00e1t\u011b\u017eov\u00fdch podm\u00ednk\u00e1ch.<\/p>\n

PWHT m\u016f\u017ee tak\u00e9 zabr\u00e1nit vod\u00edkov\u00e9 k\u0159ehkosti, kter\u00e1 je jedn\u00edm z hlavn\u00edch zdroj\u016f vzniku korozn\u00edch trhlin ve sva\u0159ovan\u00fdch ocelov\u00fdch konstrukc\u00edch.<\/p>\n

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

\u017d\u00edh\u00e1n\u00ed se pou\u017e\u00edv\u00e1 ke zlep\u0161en\u00ed fyzik\u00e1ln\u00edch vlastnost\u00ed tepeln\u011b ovlivn\u011bn\u00fdch z\u00f3n svaru (HAZ). P\u0159i sva\u0159ov\u00e1n\u00ed mohou vysok\u00e9 teploty zp\u016fsobit, \u017ee se slo\u017eky ocelov\u00fdch slitin, jako je uhl\u00edk, vysr\u00e1\u017e\u00ed do precipit\u00e1t\u016f, kter\u00e9 se stanou k\u0159ehk\u00fdmi nebo n\u00e1chyln\u00fdmi ke korozi; \u017e\u00edh\u00e1n\u00ed tyto \u00fa\u010dinky sni\u017euje, vrac\u00ed materi\u00e1lu HAZ jeho p\u016fvodn\u00ed vlastnosti, a t\u00edm poskytuje lep\u0161\u00ed fyzik\u00e1ln\u00ed vlastnosti v okol\u00ed HAZ svaru.<\/p>\n

\u017d\u00edh\u00e1n\u00ed se \u010dasto pou\u017e\u00edv\u00e1 ke zvr\u00e1cen\u00ed \u00fa\u010dink\u016f kalen\u00ed, kter\u00e9 mohou vzniknout p\u0159i procesech tv\u00e1\u0159en\u00ed za studena, jako je v\u00e1lcov\u00e1n\u00ed, kov\u00e1n\u00ed a oh\u00fdb\u00e1n\u00ed kov\u016f. D\u00edky \u017e\u00edh\u00e1n\u00ed se kov st\u00e1v\u00e1 tv\u00e1rn\u011bj\u0161\u00edm, tak\u017ee jej lze tv\u00e1\u0159et bez prask\u00e1n\u00ed p\u0159i nam\u00e1h\u00e1n\u00ed.<\/p>\n

Normalizace spo\u010d\u00edv\u00e1 v zah\u0159\u00e1t\u00ed kovu na ur\u010ditou teplotu po del\u0161\u00ed dobu, jeho udr\u017eov\u00e1n\u00ed na t\u00e9to teplot\u011b, dokud se nezpomal\u00ed jeho ochlazov\u00e1n\u00ed, a pot\u00e9 v jeho op\u011btovn\u00e9m pomal\u00e9m ochlazov\u00e1n\u00ed. Podobn\u011b jako \u017e\u00edh\u00e1n\u00ed m\u016f\u017ee normalizace zv\u00fd\u0161it ta\u017enost a sou\u010dasn\u011b sn\u00ed\u017eit tvrdost; na rozd\u00edl od \u017e\u00edh\u00e1n\u00ed se v\u0161ak p\u0159i tomto zp\u016fsobu tepeln\u00e9ho zpracov\u00e1n\u00ed nem\u011bn\u00ed jeho slo\u017een\u00ed. Ob\u011b techniky lze optimalizovat pro uvoln\u011bn\u00ed nap\u011bt\u00ed volbou vhodn\u00fdch teplot, pou\u017eit\u00edm vhodn\u00e9ho za\u0159\u00edzen\u00ed\/za\u0159\u00edzen\u00ed a sledov\u00e1n\u00edm teplot\/rychlosti chlazen\u00ed a z\u00e1rove\u0148 zaveden\u00edm kontrol kvality a postup\u016f pro zaji\u0161t\u011bn\u00ed kvality.<\/p>\n

Normalizace<\/h2>\n

Normalizace je hrub\u00e1 a z\u00e1kladn\u00ed \u00faprava atom\u00e1rn\u00ed\/krystalick\u00e9 struktury kovu za \u00fa\u010delem zlep\u0161en\u00ed jeho mechanick\u00fdch vlastnost\u00ed, odstran\u011bn\u00ed vnit\u0159n\u00edch pnut\u00ed a nepravideln\u00e9 struktury zrn zp\u016fsoben\u00e9 obr\u00e1b\u011bn\u00edm za studena nebo jin\u00fdmi procesy, d\u00edky \u010demu\u017e je kov l\u00e9pe tvarovateln\u00fd, obrobiteln\u00fd a schopen odol\u00e1vat tahov\u00fdm nam\u00e1h\u00e1n\u00edm p\u0159i pou\u017eit\u00ed.<\/p>\n

Tepeln\u00e9 zpracov\u00e1n\u00ed ocelov\u00fdch konstrukc\u00ed obecn\u011b zahrnuje zv\u00fd\u0161en\u00ed jejich teploty m\u00edrn\u011b nad horn\u00ed kritickou teplotu (kter\u00e1 se li\u0161\u00ed v z\u00e1vislosti na typu a slo\u017een\u00ed kovu) a n\u00e1sledn\u00e9 nam\u00e1\u010den\u00ed p\u0159i t\u00e9to nejvy\u0161\u0161\u00ed teplot\u011b po dobu, kter\u00e1 z\u00e1vis\u00ed na velikosti a tlou\u0161\u0165ce zpracov\u00e1van\u00e9ho pr\u016f\u0159ezu - obvykle 1 hodinu na palec tlou\u0161\u0165ky pr\u016f\u0159ezu.<\/p>\n

Normalizace vzduchem, dal\u0161\u00ed varianta tohoto procesu, prob\u00edh\u00e1 ve stejn\u00fdch kroc\u00edch jako \u00fapln\u00e1 normalizace, ale m\u00edsto okam\u017eit\u00e9ho ochlazen\u00ed se materi\u00e1l pomalu ochlazuje na vzduchu, \u010d\u00edm\u017e se dos\u00e1hne v\u011bt\u0161\u00ed tvrdosti a jemn\u011bj\u0161\u00ed struktury zrn, ne\u017e by bylo mo\u017en\u00e9 dos\u00e1hnout rychl\u00fdm ochlazen\u00edm.<\/p>\n

P\u0159edeh\u0159\u00e1t\u00ed<\/h2>\n

P\u0159edeh\u0159ev je kl\u00ed\u010dov\u00fdm krokem, kter\u00fd sni\u017euje riziko selh\u00e1n\u00ed p\u0159i sva\u0159ov\u00e1n\u00ed a pom\u00e1h\u00e1 vyhnout se n\u00e1kladn\u00e9mu p\u0159epracov\u00e1n\u00ed. Zpomalen\u00edm rychlosti ochlazov\u00e1n\u00ed svar\u016f a pos\u00edlen\u00edm jejich struktury proti prask\u00e1n\u00ed sni\u017euje p\u0159edeh\u0159ev riziko a sou\u010dasn\u011b sni\u017euje p\u0159\u00edtomnost vod\u00edku po sva\u0159ov\u00e1n\u00ed.<\/p>\n

V p\u0159edpisech a specifikac\u00edch sva\u0159ovac\u00edch postup\u016f je obvykle uvedeno, zda je vy\u017eadov\u00e1n p\u0159edeh\u0159ev, a doporu\u010dena po\u017eadovan\u00e1 teplota p\u0159edeh\u0159evu. Obecn\u011b plat\u00ed, \u017ee siln\u011bj\u0161\u00ed materi\u00e1ly nebo materi\u00e1ly s vysok\u00fdm obsahem uhl\u00edkov\u00fdch ekvivalent\u016f vy\u017eaduj\u00ed vy\u0161\u0161\u00ed teploty p\u0159edeh\u0159evu ne\u017e tenk\u00e9 materi\u00e1ly.<\/p>\n

Existuj\u00ed r\u016fzn\u00e9 zp\u016fsoby p\u0159edeh\u0159evu, nap\u0159\u00edklad oh\u0159ev ho\u0159\u00e1kem, odporov\u00fd oh\u0159ev nebo pec. Ka\u017ed\u00e1 technika m\u00e1 sv\u00e9 v\u00fdhody a nev\u00fdhody. P\u0159i v\u00fdb\u011bru vhodn\u00e9 metody pro v\u00e1\u0161 projekt se pora\u010fte s odborn\u00edkem. Volba nespr\u00e1vn\u00e9 techniky by mohla m\u00edt za n\u00e1sledek tepeln\u00fd \u0161ok, vady svaru nebo po\u0161kozen\u00ed materi\u00e1lu vy\u017eaduj\u00edc\u00ed dodate\u010dn\u00e9 tepeln\u00e9 zpracov\u00e1n\u00ed svaru - co\u017e nen\u00ed ide\u00e1ln\u00ed.<\/p>\n

Su\u0161en\u00ed<\/h2>\n

Sva\u0159ov\u00e1n\u00ed p\u0159etv\u00e1\u0159\u00ed kovy v odoln\u00e9 konstrukce, ale jeho extr\u00e9mn\u00ed teplo m\u016f\u017ee tak\u00e9 zp\u016fsobit vnit\u0159n\u00ed pnut\u00ed a jemn\u00e9 struktur\u00e1ln\u00ed deformace, kter\u00e9, pokud se ne\u0159e\u0161\u00ed, mohou \u010dasem oslabit va\u0161e komponenty. Proveden\u00ed PWHT po skon\u010den\u00ed sva\u0159ovac\u00edho projektu m\u016f\u017ee pomoci tyto probl\u00e9my vy\u0159e\u0161it a zajistit, \u017ee va\u0161e d\u00edly budou spl\u0148ovat nebo p\u0159ekon\u00e1vat pr\u016fmyslov\u00e9 normy.<\/p>\n

Odleh\u010dov\u00e1n\u00ed nap\u011bt\u00ed je b\u011b\u017en\u00e1 tepeln\u00e1 \u00faprava po sva\u0159ov\u00e1n\u00ed ocelov\u00fdch v\u00fdrobk\u016f, kter\u00e1 zahrnuje zah\u0159\u00e1t\u00ed kovu na ur\u010ditou teplotu a jeho udr\u017eov\u00e1n\u00ed po stanovenou dobu, aby se rovnom\u011brn\u011b uvolnilo vnit\u0159n\u00ed nap\u011bt\u00ed v cel\u00e9 plo\u0161e a sn\u00ed\u017eilo se riziko k\u0159ehk\u00e9ho lomu a zlep\u0161ila se tolerance deformace b\u011bhem obr\u00e1b\u011bn\u00ed a provozu. Tento proces se uk\u00e1zal jako neoceniteln\u00fd.<\/p>\n

\u017d\u00edh\u00e1n\u00ed nerezov\u00fdch ocel\u00ed roztokem m\u016f\u017ee pomoci obnovit jejich odolnost proti korozi a odstranit karbidy chromu, kter\u00e9 se tvo\u0159\u00ed p\u0159i sva\u0159ov\u00e1n\u00ed, a t\u00edm splnit nebo p\u0159ekro\u010dit p\u0159\u00edsn\u00e9 pr\u016fmyslov\u00e9 specifikace a odolat n\u00e1ro\u010dn\u00fdm podm\u00ednk\u00e1m. K dosa\u017een\u00ed p\u0159esn\u00e9 regulace teploty v pr\u016fb\u011bhu tohoto procesu m\u016f\u017ee b\u00fdt zapot\u0159eb\u00ed pokro\u010dil\u00e9 vybaven\u00ed a za\u0159\u00edzen\u00ed, aby rychlost oh\u0159evu, doba nam\u00e1\u010den\u00ed a chlazen\u00ed spl\u0148ovala nebo p\u0159ekon\u00e1vala o\u010dek\u00e1v\u00e1n\u00ed.<\/p>","protected":false},"excerpt":{"rendered":"

Post weld heat treatment (PWHT), more commonly referred to by its acronym, reduces and redistributes the residual stresses created during welding. PWHT is an essential step in preparing materials for lifelong usage under demanding load conditions. PWHT can also prevent hydrogen embrittlement, one of the main sources of stress corrosion cracking in welded steel structures. … <\/p>\n

P\u0159e\u010dt\u011bte si v\u00edce “What Is 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":[3],"tags":[],"class_list":["post-281","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\/281","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=281"}],"version-history":[{"count":1,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/281\/revisions"}],"predecessor-version":[{"id":282,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/281\/revisions\/282"}],"wp:attachment":[{"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/media?parent=281"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/categories?post=281"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/tags?post=281"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}