Izinto zokusetshenziswa ezisezingeni eliphezulu ziyisisekelo sokukhiqiza izibophelelo zekhwalithi ephezulu. Kodwa-ke, imikhiqizo eminingi yabakhiqizi be-fastener izoba neminkenke. Kungani lokhu kwenzeka?

Njengamanje, ukucaciswa okuvamile kwe-carbon structural steel wire rods ezihlinzekwa yizigayo zensimbi zasekhaya ziyi-φ 5.5- φ 45, ububanzi obuvuthiwe φ 6.5- φ 30. Kunezingozi eziningi zekhwalithi ezibangelwa ukuhlukaniswa kwe-phosphorus, njengokuhlukaniswa kwe-phosphorus induku encane yocingo kanye nebha. Umthelela wokuhlukaniswa kwe-phosphorus kanye nokuhlaziywa kokwakheka kokuqhekeka kwethulwa ngezansi ukuze kubhekwe. Ukwengezwa kwe-phosphorus kumdwebo wesigaba se-iron carbon kuzovala ngokuhambisanayo isifunda sesigaba se-austenite futhi nakanjani kwandise ibanga phakathi kwe-solidus ne-liquidus. Uma i-phosphorus equkethe insimbi ipholiswa isuka oketshezini iye kokuqinile, idinga ukudlula ebangeni elikhulu lokushisa.

Izinga lokusatshalaliswa kwe-phosphorus ensimbi lihamba kancane, futhi insimbi encibilikisiwe ene-phosphorus ephezulu (iphuzu elincibilikayo eliphansi) igcwele ama-dendrites okuqala aqinile, okuholela ekuhlukaniseni i-phosphorus. Emikhiqizweni evame ukuba nemifantu ngesikhathi sokuqalwa okubandayo noma i-extrusion ebandayo, ukuhlolwa nokuhlaziywa kwe-metallographic kubonisa ukuthi i-ferrite ne-pearlite zisatshalaliswa ngemicu, futhi kune-ferrite enebhande elimhlophe ku-matrix. Kunezindawo zokufakwa kwe-sulfide ezimpunga ngezikhathi ezithile ku-matrix ye-ferrite enebhande. Isakhiwo esinebhande se-sulfide sibizwa ngokuthi "umugqa wesipoki" ngenxa yokuhlukaniswa kwe-sulfide.
Isizathu ukuthi indawo enokwehlukaniswa kwe-phosphorus okungathi sína iveza indawo ekhanyayo emhlophe endaweni yokunothisa i-phosphorus. Ku-casting slab eqhubekayo, ngenxa yokuqukethwe okuphezulu kwe-phosphorus endaweni emhlophe, amakristalu ekholomu acebile ku-phosphorus concentrate, anciphisa okuqukethwe kwe-phosphorus. Lapho i-billet iqina, ama-austenite dendrites aqala ukuhlukaniswa nensimbi encibilikisiwe. I-phosphorus nesibabule kula ma-dendrite ayancishiswa, kodwa insimbi encibilikisiwe ekugcineni eqinile iqukethe izakhi ze-phosphorus nesulfure. Iqina phakathi kwezimbazo ze-dendrite ngoba izakhi ze-phosphorus nesulfure ziphezulu. Ngalesi sikhathi, i-sulfide iyakhiwa, futhi i-phosphorus iyancibilika ku-matrix. Ngenxa yokuthi izakhi ze-phosphorus nesulfure ziphakeme, i-sulfide iyakhiwa lapha, futhi i-phosphorus iyancibilika ku-matrix. Ngakho-ke, Ngenxa yokuqukethwe okuphezulu kwe-phosphorus nezakhi zesulfure, okuqukethwe kwekhabhoni kusisombululo esiqinile se-phosphorus kuphezulu. Ezinhlangothini zombili zebhande le-carbonaceous, okungukuthi, ezinhlangothini zombili zendawo yokucebisa i-phosphorus, kwakhiwa ibhande elide nelincane le-pearlite elihambisana nebhande elimhlophe le-ferrite, futhi izicubu ezijwayelekile eziseduze ziyahlukaniswa. Ngaphansi kwengcindezi yokushisa, i-billet izodlulela ekuqondisweni kokucubungula phakathi kwama-shafts, ngoba ibhande le-ferrite liqukethe i-phosphorus ephezulu, okungukuthi, ukuhlukaniswa kwe-phosphorus kuzoholela ekwakhiweni kwebhande elinzima elibanzi elikhanyayo elinesakhiwo esibanzi esikhanyayo se-ferrite. . Kuyabonakala ukuthi kunemicu yesulfide empunga ekhanyayo ebhandeni elibanzi elikhanyayo le-ferrite, elisakazwa ngomugqa omude webhande le-sulfide elicebile le-phosphorus ferrite, esivame ukulibiza ngokuthi "umugqa wesipoki". (Bheka umfanekiso 1-2)

I-Flange Bolt

Enkambweni yokushisa eshisayo, uma nje kukhona ukuhlukaniswa kwe-phosphorus, akunakwenzeka ukuthola i-microstructure efanayo. Okubaluleke nakakhulu, ngoba ukuhlukaniswa kwe-phosphorus kuye kwakha isakhiwo "somugqa wesipoki", nakanjani kuzonciphisa izakhiwo zemishini yezinto ezibonakalayo. Ukuhlukaniswa kwe-Phosphorus ensimbi ye-carbon bonded kuvamile, kodwa izinga layo lihlukile. Ukuhlukaniswa okunamandla kwe-phosphorus (isakhiwo "somugqa wesipoki") kuzodala imiphumela emibi kakhulu ensimbi. Ngokusobala, ukuhlukaniswa okunzima kwe-phosphorus kuyimbangela yokuqhekeka kwekhanda elibandayo. Ngenxa yokuthi okuqukethwe kwe-phosphorus ezinhlamvini ezahlukene zensimbi kuhlukile, izinto zokwakha zinamandla ahlukene nobulukhuni. Ngakolunye uhlangothi, kwenza izinto ezibonakalayo zikhiqize ukucindezeleka kwangaphakathi, okuzokwenza izinto zibe lula ukuqhekeka. Ezinto zokwakha ezinesakhiwo "somugqa wesipoki", kungenxa yokuncipha kokuqina, amandla, ubude ngemuva kokuphuka nokuncipha kwendawo, ikakhulukazi ukwehla kokuqina komthelela, ukuthi okuqukethwe kwe-phosphorus ezintweni ezinobudlelwano obukhulu nesakhiwo futhi izakhiwo zensimbi.
Emgqeni "weghost line" phakathi nendawo yombono, inani elikhulu le-sulfide elimpunga elincane elikhanyayo litholwe nge-metallography. I-non-metallic inclusions ensimbi yesakhiwo ikakhulukazi ikhona ngendlela yama-oxides nama-sulfide. Ngokuvumelana ne-GB/T10561-2005 Standard Classification Diagram Kokuqukethwe Kokufakwa Okungeyona Insimbi Ensimbi, okuqukethwe kwe-sulfide kokufakwayo Kwekilasi B kungu-2.5 noma ngaphezulu. Ukufakwa kwe-nonmetallic kungumthombo ongase ube khona wokuqhekeka. Ukuba khona kwayo kuzolimaza kakhulu ukuqhubeka nokubumbana kwesakhiwo sensimbi, ngaleyo ndlela kunciphisa kakhulu amandla e-intergranular.
Kucatshangwa ukuthi i-sulfide esakhiweni sangaphakathi "umugqa wesipoki" wensimbi iyingxenye eqhekekile kalula. Ngakho-ke, inani elikhulu lama-fasteners laqhekeka esihlokweni esibandayo kanye nokwelashwa kokushisa okucisha endaweni yokukhiqiza, okubangelwa inani elikhulu lama-sulfide amade ampunga. Le ndwangu engalukiwe yacekela phansi ukuqhubeka kwezakhiwo zensimbi futhi yandisa ingozi yokwelashwa kokushisa. “Umugqa wesipoki” awukwazi ukususwa ngokujwayelekile nezinye izindlela, futhi izakhi zokungcola kufanele zilawulwe ngokuqinile ngaphambi kokuncibilika noma izinto ezingavuthiwe zingene esitshalweni. Ngokusho kokwakheka nokukhubazeka, okufakiwe okungezona ezensimbi kuhlukaniswe i-alumina (uhlobo A) i-silicate (uhlobo C) kanye ne-spherical oxide (uhlobo D). Ukubukeka kwayo kuzonqamula ukuqhubeka kwensimbi futhi kube imigodi noma imifantu ngemva kokucwecwa, okulula ukwenza imifantu ngesikhathi sekhanda elibandayo futhi kubangele ukugxila kokucindezeleka ngesikhathi sokwelashwa kokushisa, ngaleyo ndlela kubangele imifantu ecishayo. Ngakho-ke, ukufakwa okungezona ezensimbi kufanele kulawulwe ngokuqinile. I-Structural Carbon Structural Steels GB/T700-2006 kanye ne-GB T699-2016 High Quality Carbon Steels zibeka phambili izidingo zokufakwa okungezona ezensimbi. Ezingxenyeni ezibalulekile, ngokuvamile uchungechunge olumahhadla u-A, B, C, uchungechunge oluhle alukho ngaphezu kwe-1.5, D, Ds uhlobo lwesistimu eqinile kanye nezinga 2 azikho ngaphezu kwezinga lesi-2.

I-Hebei Chengyi Engineering Materials Co., Ltd. yinkampani eneminyaka engu-21 yokukhiqiza okuqinile kanye nesipiliyoni sokuthengisa. Ama-fasteners ethu asebenzisa izinto ezingavuthiwe zekhwalithi ephezulu, ukukhiqiza okuthuthukile nobuchwepheshe bokukhiqiza, kanye nohlelo lokuphatha oluphelele lokuqinisekisa ikhwalithi yomkhiqizo. Uma ungathanda ukuthenga izinsimbi, sicela usithinte.