Ngokuthuthukiswa kwezimboni ezifana nensimbi nensimbi, imboni ye-petrochemical, imikhumbi namandla kagesi, izakhiwo ezishiselwe zivame ukukhula ngendlela yezilinganiso ezinkulu, ezinkulu neziphezulu, kanti ezinye zisasebenza ekushiseni okuphansi, cryogenic, abezindaba ezonakalisayo kanye nezinye izindawo.
Ngakho-ke, izinsimbi ezihlukahlukene ezinama-low-alloy high-strength, izinsimbi ezimaphakathi neziphezulu, izinsimbi ezinamandla amakhulu, kanye nezinto ezihlukahlukene ze-alloy ziyasetshenziswa. Kodwa-ke, ngokusetshenziswa kwala mabanga ensimbi nama-alloys, izinkinga eziningi ezintsha zilethwa ekukhiqizeni i-welding, phakathi kwazo okuvame kakhulu futhi kubi kakhulu ukuqhekeka kwe-welding.
Ngezinye izikhathi imifantu ivela ngesikhathi sokushisela futhi ngezinye izikhathi phakathi nokubekwa noma ukusebenza, okuthiwa imifantu ebambezelekile. Ngenxa yokuthi imifantu enjalo ayinakutholwa ekukhiqizeni, imifantu enjalo iyingozi kakhulu. Kunezinhlobo eziningi zokuqhekeka ezikhiqizwa inqubo yokushisela. Ngokocwaningo lwamanje, ngokwesimo semifantu, zingahlukaniswa cishe zibe yizigaba ezinhlanu ezilandelayo:
1. Umfantu oshisayo
Imifantu eshisayo ikhiqizwa emazingeni okushisa aphezulu ngesikhathi sokushisela, ngakho-ke ibizwa ngokuthi imifantu eshisayo. Kuye ngezinto zensimbi okufanele zishiswe, ukuma, ububanzi bokushisa kanye nezizathu eziyinhloko zokuqhekeka okushisayo okukhiqizwa nakho kuhlukile. Ngakho-ke, ukuqhekeka okushisayo kuhlukaniswe ngezigaba ezintathu: imifantu ye-crystallization, imifantu ye-liquefaction kanye nemifantu ye-polygonal.
1. Ukuqhekeka kwekristalu
Esigabeni sakamuva se-crystallization, ifilimu ewuketshezi eyakhiwe yi-eutectic yevolumu ephansi yenza buthaka ukuxhumana phakathi kwezinhlamvu, futhi ukuqhekeka kwenzeka ngaphansi kwesenzo sokucindezeleka okuqinile.
Ivela kakhulu ekushiseleni kwensimbi ye-carbon steel kanye ne-low-alloy steel enokungcola okwengeziwe (okuqukethwe okuphezulu kwesibabule, i-phosphorus, insimbi, ikhabhoni, ne-silicon) kanye nokushisela kwe-single-phase austenitic steel, ama-alloys asekelwe ku-nickel namanye ama-alloys e-aluminium. phakathi. Ezimweni ezingazodwana, ukuqhekeka kwekristalu kungenzeka futhi endaweni ethinteke ukushisa.
2. Izinga lokushisa eliphezulu liquefaction crack
Ngaphansi kwesenzo sokushisa okuphezulu komjikelezo we-welding thermal, ukulungiswa kabusha kwenzeka phakathi kwendawo ethintekile ukushisa kanye nezingqimba ze-welding multi-layer, futhi imifantu ikhiqizwa ngaphansi kwesenzo sokucindezeleka.
Ivela kakhulu ezinsimbini eziqine kakhulu eziqukethe i-chromium ne-nickel, izinsimbi ze-austenitic, namanye ama-alloys asekelwe ku-nickel endaweni eseduze yomthungo noma phakathi kokushisela kwezendlalelo eziningi. Lapho okuqukethwe kwesulfure, i-phosphorus ne-silicon carbon kusisekelo sensimbi nocingo lokushisela kuphezulu, ukuthambekela kokuqhekeka kwe-liquefaction kuzokhula kakhulu.
Isikhathi sokuthumela: Apr-18-2022