{"id":289,"date":"2025-09-03T13:37:24","date_gmt":"2025-09-03T13:37:24","guid":{"rendered":"https:\/\/pwhtsolutions.net\/?p=289"},"modified":"2025-09-03T13:37:25","modified_gmt":"2025-09-03T13:37:25","slug":"tepelne-zpracovani-po-svarovani-7","status":"publish","type":"post","link":"http:\/\/pwhtsolutions.net\/cs\/post-heat-welding-heat-treatment\/","title":{"rendered":"Tepeln\u00e9 zpracov\u00e1n\u00ed po tepeln\u00e9m sva\u0159ov\u00e1n\u00ed"},"content":{"rendered":"

Sva\u0159ov\u00e1n\u00ed po zah\u0159\u00e1t\u00ed zahrnuje zah\u0159\u00e1t\u00ed materi\u00e1lu na jinou teplotu, ne\u017e byla teplota po\u010d\u00e1te\u010dn\u00edho p\u0159edeh\u0159\u00e1t\u00ed, aby nedo\u0161lo k jeho p\u0159\u00edli\u0161 rychl\u00e9mu ochlazen\u00ed a vzniku vnit\u0159n\u00edch pnut\u00ed nebo nep\u0159\u00edzniv\u00fdch metalurgick\u00fdch zm\u011bn.<\/p>\n

PWHT sni\u017euje tahov\u00e1 zbytkov\u00e1 nap\u011bt\u00ed p\u0159ibli\u017en\u011b na 30% meze kluzu svarov\u00e9ho kovu, \u010d\u00edm\u017e pom\u00e1h\u00e1 p\u0159edch\u00e1zet riziku k\u0159ehk\u00e9ho lomu a snadn\u011bji dosahuje vynikaj\u00edc\u00edch mechanick\u00fdch vlastnost\u00ed.<\/p>\n

Odstra\u0148ov\u00e1n\u00ed stresu<\/h2>\n

Tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed lze prov\u00e1d\u011bt u v\u0161ech druh\u016f oceli, aby se zm\u00edrnilo vnit\u0159n\u00ed pnut\u00ed, kter\u00e9 by mohlo v\u00e9st k deformaci nebo p\u0159ed\u010dasn\u00e9mu selh\u00e1n\u00ed svaru, a to zah\u0159\u00e1t\u00edm obrobku na p\u0159esnou teplotu po nastavitelnou dobu v z\u00e1vislosti na typu a tlou\u0161\u0165ce materi\u00e1lu.<\/p>\n

Techniky uvol\u0148ov\u00e1n\u00ed nap\u011bt\u00ed, jako je vypalov\u00e1n\u00ed vod\u00edkem a p\u0159edeh\u0159ev, vy\u017eaduj\u00ed pou\u017eit\u00ed p\u0159edeh\u0159\u00edvac\u00ed pece; p\u0159edeh\u0159ev m\u016f\u017ee b\u00fdt nutn\u00fd p\u0159i pr\u00e1ci s uhl\u00edkov\u00fdmi a vysokolegovan\u00fdmi ocelemi a siln\u011bj\u0161\u00edmi materi\u00e1ly.<\/p>\n

Pro dosa\u017een\u00ed optim\u00e1ln\u00edch v\u00fdsledk\u016f mus\u00ed b\u00fdt p\u0159edeh\u0159\u00edvac\u00ed pece vybaveny termo\u010dl\u00e1nky, kter\u00e9 monitoruj\u00ed p\u0159esnou rychlost oh\u0159evu a chlazen\u00ed, aby se sn\u00ed\u017eil tepeln\u00fd \u0161ok, oblasti svaru dos\u00e1hly rychleji c\u00edlov\u00e9 teploty a zabr\u00e1nilo se oxidaci, op\u011btovn\u00e9mu zpevn\u011bn\u00ed, p\u0159eh\u0159\u00e1t\u00ed nebo vod\u00edkov\u00e9 k\u0159ehkosti v oblasti svaru. Za t\u00edmto \u00fa\u010delem je t\u0159eba zabr\u00e1nit tepeln\u00e9mu \u0161oku, aby z\u00f3ny svaru dos\u00e1hly a udr\u017eely si c\u00edlovou teplotu bez tepeln\u00e9ho \u0161oku, \u010d\u00edm\u017e se eliminuje tepeln\u00fd \u0161ok i p\u0159eh\u0159\u00e1t\u00ed, kter\u00e9 by mohlo m\u00edt za n\u00e1sledek vznik vod\u00edkov\u00e9 k\u0159ehkosti v d\u016fsledku oxidace p\u0159eh\u0159\u00e1t\u00fdch z\u00f3n svaru, retemperaci v z\u00f3n\u00e1ch svaru i p\u0159eh\u0159\u00e1t\u00ed z\u00f3n svaru v d\u016fsledku nerovnom\u011brn\u00fdch rychlost\u00ed oh\u0159evu mezi z\u00f3nami; sn\u00ed\u017een\u00ed pevnosti\/sn\u00ed\u017een\u00ed tvrdosti v z\u00f3n\u011b svaru kontrolu teploty dosa\u017een\u00edm c\u00edlov\u00e9 c\u00edlov\u00e9 teploty bez p\u0159eh\u0159\u00e1t\u00ed k riziku vod\u00edkov\u00e9 k\u0159ehkosti vyvolan\u00e9 vod\u00edkovou k\u0159ehkost\u00ed sn\u00ed\u017een\u00ed rizika nebo p\u0159eh\u0159\u00e1t\u00ed bez p\u0159eh\u0159\u00e1t\u00ed z\u00f3ny svaru a tak zajistitz\u00f3ny svaru, kter\u00e9 by mohly zp\u016fsobit pevnost\/tvrdost kovu sn\u00ed\u017een\u00ed pevnosti\/tvrdosti\/sn\u00ed\u017een\u00ed tvrdosti ze sn\u00ed\u017een\u00ed v d\u016fsledku p\u0159eh\u0159\u00e1t\u00ed\/temperace nebo sn\u00ed\u017een\u00ed pevnosti\/tvrdosti v d\u016fsledku z\u00f3ny svaru udr\u017eov\u00e1n\u00edm na jej\u00ed c\u00edlov\u00e9 teplot\u011b sn\u00ed\u017een\u00ed v koroze svarov\u00e9 z\u00f3ny nebo p\u0159eh\u0159\u00e1t\u00ed, kter\u00e9 by mohly sn\u00ed\u017eit sn\u00ed\u017een\u00ed pevnosti\/tvrdosti sn\u00ed\u017een\u00ed pevnosti\/tvrdosti nebo sn\u00ed\u017een\u00ed tvrdosti t\u00edm, \u017ee se snadn\u011bji stanou n\u00e1chyln\u00fdmi v d\u016fsledku vod\u00edkov\u00e9 k\u0159ehkosti je p\u0159eh\u0159\u00e1t\u00ed\/dehydratace\/op\u011btovn\u00e9ho temperov\u00e1n\u00ed\/redukce ztr\u00e1ty nebo p\u0159eh\u0159\u00e1t\u00ed sn\u00ed\u017een\u00ed ztr\u00e1ty t\u00edm sn\u00ed\u017een\u00ed pevnosti\/tvrdosti nebo po\u0161kozen\u00ed\/tvrdosti\/tvrdosti sn\u00ed\u017een\u00ed pevnosti\/tvrdosti nebo p\u0159eh\u0159\u00e1t\u00ed\/k\u0159ehkosti ztr\u00e1ty v d\u016fsledku sn\u00ed\u017een\u00ed pevnosti\/tvrdosti, kdy\u017e je to nutn\u00e9 po tepeln\u00e9 ztr\u00e1ty v d\u016fsledku p\u0159eh\u0159\u00e1t\u00ed sn\u00ed\u017een\u00e9 ve svarov\u00e9, vod\u00edkov\u00e9 k\u0159ehkosti\/ sn\u00ed\u017een\u00ed v\u00fdsledn\u00e9ho svaru.<\/p>\n

Normalizace<\/h2>\n

Normalizace dodate\u010dn\u011b tepeln\u011b zpracovan\u00fdch profil\u016f je \u00fa\u010dinn\u00fd zp\u016fsob, jak zm\u00edrnit vnit\u0159n\u00ed pnut\u00ed, obnovit jejich mikrostrukturu do p\u0159irozen\u00e9ho stavu, zlep\u0161it mechanick\u00e9 vlastnosti a sn\u00ed\u017eit anizotropii zp\u016fsobenou nerovnom\u011brn\u00fdm oh\u0159evem b\u011bhem sva\u0159ov\u00e1n\u00ed nebo jin\u00fdch proces\u016f, usnadnit tvarov\u00e1n\u00ed nebo v\u00fdrobu, sn\u00ed\u017eit deformace nebo prask\u00e1n\u00ed b\u011bhem nebo po obr\u00e1b\u011bn\u00ed a tak\u00e9 udr\u017eet konzistenci vlastnost\u00ed mezi jednotliv\u00fdmi \u0161ar\u017eemi.<\/p>\n

Normalizace podobn\u011b jako \u017e\u00edh\u00e1n\u00ed zahrnuje pomal\u00e9 a opatrn\u00e9 zah\u0159\u00edv\u00e1n\u00ed sva\u0159ovan\u00fdch sou\u010d\u00e1st\u00ed nad teplotu rekrystalizace, aby se uvolnilo vnit\u0159n\u00ed nap\u011bt\u00ed, a pot\u00e9 postupn\u00e9 ochlazov\u00e1n\u00ed vzduchem nebo postupn\u00e9 ochlazov\u00e1n\u00ed vodou. Normalizace se od \u017e\u00edh\u00e1n\u00ed li\u0161\u00ed t\u00edm, \u017ee jej\u00ed ochlazov\u00e1n\u00ed prob\u00edh\u00e1 rychleji, co\u017e m\u00e1 za n\u00e1sledek m\u00e9n\u011b tv\u00e1rn\u00fd v\u00fdsledn\u00fd kov ne\u017e p\u0159i \u017e\u00edh\u00e1n\u00ed; to \u010din\u00ed z normalizace z\u00e1sadn\u00ed proces pro zaji\u0161t\u011bn\u00ed pevnosti a spolehlivosti kritick\u00fdch sou\u010d\u00e1st\u00ed, jako jsou konstruk\u010dn\u00ed prvky.<\/p>\n

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

\u017d\u00edh\u00e1n\u00ed sni\u017euje vnit\u0159n\u00ed pnut\u00ed a eliminuje k\u0159ehk\u00e9 trhliny ve sva\u0159ovan\u00fdch sou\u010d\u00e1stech, \u010d\u00edm\u017e zvy\u0161uje ta\u017enost a zlep\u0161uje vyrobitelnost materi\u00e1lu.<\/p>\n

Metodou \u0159\u00edzen\u00e9 rekrystalizace kov\u016f je zah\u0159\u00edv\u00e1n\u00ed d\u00edl\u016f nebo cel\u00e9ho v\u00fdrobku na teplotu p\u0159esahuj\u00edc\u00ed bod rekrystalizace a n\u00e1sledn\u00e9 postupn\u00e9 ochlazov\u00e1n\u00ed v pr\u016fb\u011bhu \u010dasu. Odborn\u00edci rad\u00ed, jak\u00e9 konkr\u00e9tn\u00ed teploty a doby nam\u00e1\u010den\u00ed jsou vhodn\u00e9 pro konkr\u00e9tn\u00ed typy oceli.<\/p>\n

Lze pou\u017e\u00edt techniky p\u0159edeh\u0159evu, jako jsou plynov\u00e9 ho\u0159\u00e1ky, kysl\u00edkov\u00e9 plameny, elektrick\u00e9 deky nebo induk\u010dn\u00ed oh\u0159ev; je d\u016fle\u017eit\u00e9, aby rozlo\u017een\u00ed tepla bylo rovnom\u011brn\u00e9 v cel\u00e9 z\u00e1jmov\u00e9 oblasti, aby se zabr\u00e1nilo intenzivn\u00edmu a nerovnom\u011brn\u00e9mu oh\u0159evu, kter\u00fd zpomaluje rychlost chladnut\u00ed nebo vyvol\u00e1v\u00e1 ne\u017e\u00e1douc\u00ed metalurgick\u00e9 zm\u011bny z\u00e1kladn\u00edho kovu - to m\u016f\u017ee m\u00edt za n\u00e1sledek tepeln\u00e9 prask\u00e1n\u00ed, deformace nebo selh\u00e1n\u00ed svaru. Je vhodn\u00e9 pou\u017e\u00edt technologii monitorov\u00e1n\u00ed teploty, aby bylo zaji\u0161t\u011bno, \u017ee se oblasti svaru budou zah\u0159\u00edvat p\u0159im\u011b\u0159en\u011b dlouho a rovnom\u011brn\u011b - m\u016f\u017ee j\u00edt nap\u0159\u00edklad o pou\u017eit\u00ed infra\u010derven\u00fdch kamer nebo termo\u010dl\u00e1nk\u016f.<\/p>\n

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

Tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed pomoc\u00ed expanzn\u00edho oh\u0159evu m\u016f\u017ee \u00fa\u010dinn\u011b zm\u00edrnit zbytkov\u00e1 nap\u011bt\u00ed a zv\u00fd\u0161it integritu sva\u0159ovan\u00fdch sou\u010d\u00e1st\u00ed. Pe\u010dliv\u00fdm zah\u0159\u00e1t\u00edm kov\u016f na \u0159\u00edzenou teplotu umo\u017e\u0148uje expanzn\u00ed oh\u0159ev okoln\u00edmu materi\u00e1lu expandovat kolem svaru, \u010d\u00edm\u017e zm\u00edr\u0148uje vnit\u0159n\u00ed pnut\u00ed a z\u00e1rove\u0148 jej chr\u00e1n\u00ed p\u0159ed deformacemi nebo poruchami pod tlakem.<\/p>\n

N\u00e1sledn\u00fd oh\u0159ev m\u016f\u017ee sn\u00ed\u017eit riziko vzniku vod\u00edkem indukovan\u00fdch trhlin (HIC), ke kter\u00e9mu doch\u00e1z\u00ed, kdy\u017e do svaru pronikne vysok\u00e9 mno\u017estv\u00ed okoln\u00edho vod\u00edku a zp\u016fsob\u00ed vznik trhlin. Po sva\u0159ov\u00e1n\u00ed by se m\u011bl svar ihned po vychladnut\u00ed p\u0159i vhodn\u00e9 teplot\u011b na ur\u010ditou dobu znovu zah\u0159\u00e1t, aby se zachycen\u00e9 atomy vod\u00edku uvolnily z jeho j\u00e1dra a difundovaly ven, \u010d\u00edm\u017e se sn\u00ed\u017e\u00ed pravd\u011bpodobnost vzniku HIC.<\/p>\n

PWHT nejen\u017ee sni\u017euje a p\u0159erozd\u011bluje zbytkov\u00e1 nap\u011bt\u00ed, ale m\u016f\u017ee tak\u00e9 usnadnit popou\u0161t\u011bn\u00ed nebo st\u00e1rnut\u00ed a zlep\u0161it tak ta\u017enost a pevnost svar\u016f, pokud se prov\u00e1d\u00ed spr\u00e1vn\u011b, s teplotami a \u010dasy p\u0159izp\u016fsoben\u00fdmi konkr\u00e9tn\u011b pro o\u0161et\u0159ovan\u00e9 materi\u00e1ly. Tyto v\u00fdhody v\u0161ak vznikaj\u00ed pouze tehdy, pokud se prov\u00e1d\u00ed podle spr\u00e1vn\u00fdch postup\u016f a p\u0159i o\u0161et\u0159en\u00ed se pou\u017e\u00edvaj\u00ed vhodn\u00e9 \u010dasy a teploty.<\/p>","protected":false},"excerpt":{"rendered":"

Post heat welding involves heating material at temperatures different from its initial preheat, in order to stop it from cooling too rapidly and cause internal stresses or unfavorable metallurgical changes. PWHT reduces tensile residual stresses to approximately 30% of a weld metal’s yield strength, helping prevent the risk of brittle fracture and more easily achieve … <\/p>\n

P\u0159e\u010dt\u011bte si v\u00edce “Post Heat Welding 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-289","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\/289","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=289"}],"version-history":[{"count":1,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/289\/revisions"}],"predecessor-version":[{"id":290,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/289\/revisions\/290"}],"wp:attachment":[{"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/media?parent=289"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/categories?post=289"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/tags?post=289"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}