{"id":267,"date":"2025-08-23T22:35:15","date_gmt":"2025-08-23T22:35:15","guid":{"rendered":"https:\/\/pwhtsolutions.net\/?p=267"},"modified":"2025-08-23T22:35:16","modified_gmt":"2025-08-23T22:35:16","slug":"postup-p91-pwht","status":"publish","type":"post","link":"https:\/\/pwhtsolutions.net\/cs\/the-p91-pwht-procedure\/","title":{"rendered":"Postup PWHT P91"},"content":{"rendered":"

Martenzitick\u00e1 ocel P91 se hojn\u011b vyu\u017e\u00edv\u00e1 v n\u00e1ro\u010dn\u00fdch aplikac\u00edch, v\u010detn\u011b elektr\u00e1ren s nadkritick\u00fdm provozem. Vyzna\u010duje se vysokou pevnost\u00ed, tepelnou stabilitou a odolnost\u00ed proti korozi \u2013 d\u00edky t\u011bmto vlastnostem je pro tyto \u00fa\u010dely velmi vhodn\u00e1.<\/p>\n

U svar\u016f z oceli t\u0159\u00eddy 91 se \u010dasto vy\u017eaduje tepeln\u00e9 zpracov\u00e1n\u00ed po sva\u0159ov\u00e1n\u00ed (PWHT) za \u00fa\u010delem sn\u00ed\u017een\u00ed zbytkov\u00fdch nap\u011bt\u00ed a zv\u00fd\u0161en\u00ed hou\u017eevnatosti; toto zpracov\u00e1n\u00ed v\u0161ak m\u016f\u017ee b\u00fdt \u010dasov\u011b n\u00e1ro\u010dn\u00e9 a n\u00e1kladn\u00e9; proto se tento projekt zab\u00fdv\u00e1 alternativn\u00edmi zp\u016fsoby zpracov\u00e1n\u00ed svar\u016f z oceli t\u0159\u00eddy 91 s vyu\u017eit\u00edm sva\u0159ov\u00e1n\u00ed s \u0159\u00edzen\u00fdm nan\u00e1\u0161en\u00edm.<\/p>\n

Modifikovan\u00e1 metoda MIG se zkratem<\/h2>\n

Na rozd\u00edl od b\u011b\u017en\u00fdch metod sva\u0159ov\u00e1n\u00ed s kr\u00e1tk\u00fdm obvodem vyu\u017e\u00edv\u00e1 tato technika periodick\u00fd kontakt mezi elektrodou a tavnou l\u00e1zn\u00ed za \u00fa\u010delem p\u0159enosu roztaven\u00e9ho kovu mezi nimi, \u010d\u00edm\u017e se omezuje tvorba rozst\u0159ik\u016f a zlep\u0161uje kvalita svaru t\u00edm, \u017ee se zabra\u0148uje zachycov\u00e1n\u00ed plynu ve svaru, co\u017e ji \u010din\u00ed obzvl\u00e1\u0161t\u011b vhodnou pro aplikace, kde hraje d\u016fle\u017eitou roli tlou\u0161\u0165ka materi\u00e1lu.<\/p>\n

Tato sva\u0159ovac\u00ed metoda se vyzna\u010duje tak\u00e9 n\u00edzk\u00fdm tepeln\u00fdm p\u0159\u00edkonem, d\u00edky \u010demu\u017e je vhodn\u00e1 pro tenk\u00e9 materi\u00e1ly, kter\u00e9 by se p\u0159i vysok\u00fdch teplot\u00e1ch mohly zdeformovat nebo pok\u0159ivit. Dr\u00e1tov\u00e1 elektroda se dot\u00fdk\u00e1 obrobku n\u011bkolikr\u00e1t za sekundu, ne\u017e dojde k kr\u00e1tk\u00e9mu zkratu a zhasnut\u00ed oblouku \u2013 tento cyklus rychle odv\u00e1d\u00ed teplo a z\u00e1rove\u0148 sni\u017euje p\u0159enos kovu do svarov\u00e9 l\u00e1zn\u011b.<\/p>\n

Modifikovan\u00e9 sva\u0159ov\u00e1n\u00ed metodou MIG se zkratem nab\u00edz\u00ed r\u016fzn\u00e9 tvary proudov\u00e9 vlny. N\u011bkter\u00e9 varianty poskytuj\u00ed v\u00edce mo\u017enost\u00ed nastaven\u00ed ne\u017e jin\u00e9, v\u010detn\u011b ni\u017e\u0161\u00edch hodnot proudu ve f\u00e1zi \u010dek\u00e1n\u00ed a dvoustup\u0148ov\u00fdch pulz\u016f. Krom\u011b toho m\u00e1 rychlost poklesu v\u00fdkonu b\u011bhem cykl\u016f zapalov\u00e1n\u00ed a zhas\u00edn\u00e1n\u00ed v\u00fdznamn\u00fd vliv na okam\u017eit\u00e9 teplo p\u0159iv\u00e1d\u011bn\u00e9 do svarov\u00e9 l\u00e1zn\u011b.<\/p>\n

Impulzn\u00ed MIG<\/h2>\n

Pulzn\u00ed sva\u0159ov\u00e1n\u00ed metodou MIG je ide\u00e1ln\u00ed pro aplikace vy\u017eaduj\u00edc\u00ed v\u011bt\u0161\u00ed kontrolu, jako jsou nap\u0159\u00edklad p\u0159\u00edpady, kdy hroz\u00ed prop\u00e1len\u00ed nebo deformace hotov\u00fdch v\u00fdrobk\u016f. D\u00edky mo\u017enosti nastaven\u00ed \u0161pi\u010dkov\u00e9ho proudu, z\u00e1kladn\u00edho proudu a frekvence pulz\u016f umo\u017e\u0148uje pulzn\u00ed sva\u0159ov\u00e1n\u00ed MIG sv\u00e1\u0159e\u010d\u016fm p\u0159esn\u011b \u0159\u00eddit p\u0159\u00edsun tepla do oblouku prost\u0159ednictv\u00edm nastaven\u00ed \u0161pi\u010dkov\u00e9ho proudu, regulace z\u00e1kladn\u00edho proudu a nastaven\u00ed frekvence pulz\u016f. Tato vylep\u0161en\u00e1 tepeln\u00e1 regulace umo\u017e\u0148uje dos\u00e1hnout kvalitn\u011bj\u0161\u00edho povrchu.<\/p>\n

Krom\u011b toho omezuje probl\u00e9my souvisej\u00edc\u00ed s p\u0159eh\u0159\u00edv\u00e1n\u00edm, kter\u00e9 se vyskytuj\u00ed u jin\u00fdch sva\u0159ovac\u00edch proces\u016f, co\u017e oper\u00e1tor\u016fm umo\u017e\u0148uje pou\u017e\u00edvat dr\u00e1ty s v\u011bt\u0161\u00edm pr\u016fm\u011brem a vy\u0161\u0161\u00ed rychlosti posuvu, \u010d\u00edm\u017e se zvy\u0161uje produktivita a p\u0159edch\u00e1z\u00ed se n\u00e1kladn\u00fdm oprav\u00e1m po sva\u0159ov\u00e1n\u00ed.<\/p>\n

Impulzn\u00ed sva\u0159ov\u00e1n\u00ed metodou MIG p\u0159in\u00e1\u0161\u00ed pr\u016fmyslu \u0159adu v\u00fdhod, mezi n\u011b\u017e pat\u0159\u00ed lep\u0161\u00ed kvalita svaru, men\u0161\u00ed deformace a vy\u0161\u0161\u00ed p\u0159esnost p\u0159i pr\u00e1ci s materi\u00e1ly citliv\u00fdmi na teplo. N\u011bkter\u00e9 zdroje nap\u00e1jen\u00ed dokonce nab\u00edzej\u00ed mo\u017enost du\u00e1ln\u00edho pulzov\u00e1n\u00ed, \u010d\u00edm\u017e tyto v\u00fdhody je\u0161t\u011b v\u00edce roz\u0161i\u0159uj\u00ed \u2013 sv\u00e1\u0159e\u010d\u016fm tak umo\u017e\u0148uj\u00ed snadn\u011bj\u0161\u00ed p\u0159ep\u00edn\u00e1n\u00ed mezi p\u0159ednastaven\u00fdmi postupy a z\u00e1rove\u0148 zkracuj\u00ed dobu za\u0161kolov\u00e1n\u00ed nov\u00fdch sv\u00e1\u0159e\u010d\u016f.<\/p>\n

Induk\u010dn\u00ed oh\u0159ev<\/h2>\n

Induk\u010dn\u00ed oh\u0159ev vyu\u017e\u00edv\u00e1 elektromagnetickou indukci k oh\u0159evu elektricky vodiv\u00fdch materi\u00e1l\u016f, jako je kov. Tato bezkontaktn\u00ed metoda pom\u00e1h\u00e1 minimalizovat d\u00e9lku v\u00fdrobn\u00edch cykl\u016f a spot\u0159ebu energie, d\u00edky \u010demu\u017e je ide\u00e1ln\u00ed pro vysok\u00e9 v\u00fdrobn\u00ed v\u00fdkony. Obsluha nav\u00edc m\u016f\u017ee p\u0159esn\u011b regulovat teplotu, \u010d\u00edm\u017e minimalizuje deformace a kroucen\u00ed obrobk\u016f.<\/p>\n

Induk\u010dn\u00ed oh\u0159ev umo\u017e\u0148uje rychle dos\u00e1hnout vysok\u00fdch teplot, \u010d\u00edm\u017e eliminuje nutnost zah\u0159\u00edvac\u00edch a ochlazovac\u00edch cykl\u016f a \u0161et\u0159\u00ed tak \u010das i pen\u00edze v odv\u011btv\u00edch s kr\u00e1tk\u00fdmi term\u00edny, jako je leteck\u00fd a automobilov\u00fd pr\u016fmysl.<\/p>\n

Induk\u010dn\u00ed oh\u0159ev m\u00e1 v\u0161ak omezenou hloubku pronik\u00e1n\u00ed, proto\u017ee elektromagnetick\u00e9 pole vytv\u00e1\u0159en\u00e9 oh\u0159\u00edvac\u00ed c\u00edvkou oh\u0159\u00edv\u00e1 pouze povrch d\u00edlu. S rostouc\u00ed frekvenc\u00ed se sice hloubka pronik\u00e1n\u00ed m\u00edrn\u011b zvy\u0161uje, co\u017e v\u0161ak m\u016f\u017ee p\u0159edstavovat probl\u00e9m v aplikac\u00edch vy\u017eaduj\u00edc\u00edch hlub\u0161\u00ed pronik\u00e1n\u00ed. Induk\u010dn\u00ed oh\u0159ev nav\u00edc vy\u017eaduje odborn\u00e9 znalosti v oblasti konstrukce c\u00edvky a nastaven\u00ed frekvence, kter\u00e9 ovliv\u0148uj\u00ed chov\u00e1n\u00ed materi\u00e1lu, co\u017e \u010din\u00ed tuto formu oh\u0159evu \u010dasto n\u00e1kladn\u011bj\u0161\u00ed ne\u017e alternativn\u00ed metody oh\u0159evu.<\/p>\n

Sva\u0159ovac\u00ed proces<\/h2>\n

Ocel P91 se sice vyzna\u010duje vynikaj\u00edc\u00edm pom\u011brem pevnosti k hmotnosti, je v\u0161ak n\u00e1chyln\u00e1 k prask\u00e1n\u00ed zp\u016fsoben\u00e9mu vod\u00edkem, a proto je nutn\u00e9 p\u0159\u00edsn\u011b kontrolovat parametry sva\u0159ov\u00e1n\u00ed, aby se tento jev minimalizoval. Rovn\u011b\u017e je nutn\u00e9 p\u0159\u00edsn\u011b dodr\u017eovat teploty p\u0159edeh\u0159evu a mezi\u0161vov\u00e9 teploty, p\u0159i\u010dem\u017e \u201crozmez\u00ed\u201d sva\u0159itelnosti by m\u011blo z\u016fstat \u00fazk\u00e9, aby bylo mo\u017en\u00e9 dos\u00e1hnout kr\u00e1tk\u00fdch dob zu\u0161lech\u0165ov\u00e1n\u00ed a popou\u0161t\u011bn\u00ed, co\u017e p\u0159isp\u011bje k minimalizaci HIC.<\/p>\n

Modifikovan\u00e9 sva\u0159ov\u00e1n\u00ed metodou MIG se zkratem nab\u00edz\u00ed v tomto ohledu oproti metod\u011b TIG n\u011bkolik v\u00fdhod: rychlost posuvu je t\u0159ikr\u00e1t a\u017e \u010dty\u0159ikr\u00e1t vy\u0161\u0161\u00ed a \u010dasto odpad\u00e1 nutnost zp\u011btn\u00e9ho proplachov\u00e1n\u00ed, co\u017e \u0161et\u0159\u00ed jak n\u00e1klady, tak spot\u0159ebu plynu. Nav\u00edc pou\u017eit\u00ed pokro\u010dil\u00fdch tvar\u016f vlny m\u016f\u017ee pomoci zabr\u00e1nit prop\u00e1len\u00ed ko\u0159enov\u00e9ho \u0161vu, \u010d\u00edm\u017e se zlep\u0161\u00ed mikrostruktura svaru a jeho temperov\u00e1n\u00ed.<\/p>","protected":false},"excerpt":{"rendered":"

Martenzitick\u00e1 ocel P91 je \u0161iroce vyu\u017e\u00edv\u00e1na pro n\u00e1ro\u010dn\u00e9 aplikace, v\u010detn\u011b nadkritick\u00fdch elektr\u00e1ren. Vyzna\u010duje se vysokou pevnost\u00ed, tepelnou stabilitou a odolnost\u00ed proti korozi - vlastnostmi, kter\u00e9 ji \u010din\u00ed vhodnou pro tyto \u00fakoly. U svar\u016f t\u0159\u00eddy 91 se \u010dasto vy\u017eaduje PWHT, aby se sn\u00ed\u017eila zbytkov\u00e1 nap\u011bt\u00ed a zv\u00fd\u0161ila hou\u017eevnatost; tato \u00faprava v\u0161ak m\u016f\u017ee b\u00fdt \u010dasov\u011b n\u00e1ro\u010dn\u00e1 a n\u00e1kladn\u00e1; ... <\/p>\n

P\u0159e\u010dt\u011bte si v\u00edce “The P91 PWHT Procedure”<\/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-267","post","type-post","status-publish","format-standard","hentry","category-pwht-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/267","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=267"}],"version-history":[{"count":1,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/267\/revisions"}],"predecessor-version":[{"id":268,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/posts\/267\/revisions\/268"}],"wp:attachment":[{"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/media?parent=267"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/categories?post=267"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pwhtsolutions.net\/cs\/wp-json\/wp\/v2\/tags?post=267"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}