Sau da yawa muna cewa bututun da aka faɗaɗa mai zafi yana nufin bututun ƙarfe mai ƙarancin yawa amma yana da ƙarfi sosai, Ƙungiyar Ma'aunin Ƙasa ta China ta tsara cewa bututun ƙarfe da aka faɗaɗa mai zafi ya kamata ya zama bututun ƙarfe mai girman diamita wanda aka faɗaɗa kuma ya lalace bayan dumama bututun ƙarfe mara komai. Fasahar faɗaɗa mai zafi ita ce faɗaɗa diamita na bututun ta hanyar nakasar radial, wato, ba na yau da kullun ba, samfuran musamman na bututu marasa sumul za a iya samar da su ta amfani da bututun yau da kullun, kuma farashin yana da ƙasa kuma ingancin samarwa yana da yawa. Hanya ce ta sarrafawa gama gari don bututu marasa sumul. Saboda haɓakar manyan sigogi na tukunyar wutar lantarki da haɓaka manyan masana'antun mai, buƙatar bututu marasa sumul masu girma yana ƙaruwa, kuma yana da wahala ga na'urorin birgima bututu su samar da bututu mara sumul wanda diamita ya fi 508mm, rabon diamita na waje zuwa kauri bango (D/S)>25, fasahar faɗaɗa mai zafi, musamman fasahar faɗaɗa mai zafi mai matsakaicin mita mai inganci ta haɓaka ta haka a hankali.
Faɗaɗa bututun mai matakai biyu da ake amfani da shi don bututun ƙarfe mai faɗaɗa zafi ya haɗa fasahar faɗaɗa diamita mai siffar mazugi, fasahar dumama mai matsakaicin mita ta dijital, da fasahar hydraulic a cikin injina ɗaya. Tare da tsarinta mai ma'ana, ƙarancin amfani da makamashi, ƙarancin saka hannun jari a gini, da kyau Ingancin samfura, kewayon kayan aiki da ƙayyadaddun samfura, sassauci da ƙarancin daidaitawar samar da kayayyaki sun maye gurbin fasahar faɗaɗa diamita ta gargajiya ta masana'antar bututun ƙarfe.
Ya kamata a lura cewa halayen injinan bututun ƙarfe masu zafi sun ɗan fi muni fiye da bututun ƙarfe masu zafi.
Tsarin faɗaɗa zafi na bututun gabaɗaya shine a gyara bututun a kan sukurin jagora, a sanya wani mazugi mai siffar mazugi a saman bututun mai diamita mafi girma fiye da diamita na bututun zuwa ɗayan ƙarshen bututun, sannan a haɗa kuma a gyara ɗayan mazugi a cikin bututun. Haɗin da ke tsakanin bututun da mazugi na sama yana ƙasa da mazugi mai dumama na matsakaicin mita, domin a magance dumama da sauri da fashewa, kuna buƙatar wucewa da ruwa a cikin bututun da farko, fara dumama mazugi, kuma bayan isa ga takamaiman zafin jiki, sukurin da ke haɗa bututun yana tura bututun, don haka bututun ya motsa zuwa mazugi na sama ya faɗaɗa. Mazugi na sama yana faɗaɗa diamita na bututun. Bayan bututun gaba ɗaya ya wuce, bututun ba zai zama madaidaiciya ba saboda tsarin faɗaɗa zafi, don haka yana buƙatar daidaita shi.
Abin da ke sama shine ainihin abin da ke cikin fasahar faɗaɗa zafi.
Ga yadda tsarin bututun da aka faɗaɗa na thermal yake
Faɗaɗa nauyi:
ƙarfen carbon: (kauri-diamita)× kauri× 0.02466 = nauyit na mita ɗaya (kg)
gami: (diamita-kauri)× kauri× 0.02483 = nauyina mita ɗaya (kg)
adadin mita bayan an faɗaɗa zafi:
diamita na bututu na asali÷ diamita mai zafi da aka faɗaɗa× 1.04× tsawon *
Mita bututu na asali:
tsawon da aka faɗaɗa× (diamita÷ diamita na bututu na asali÷ 1.04)
gudu:
100000÷ (asali diamita-kauri× kauri)
kauri:
kauri da aka faɗaɗa (sau 1)) = Kauri na asali na bututu× 0.92
Faɗaɗa kauri (sau 2) = Kauri na asali na bututu*0.84
Diamita:
Faɗaɗa diamita = girman mold + faɗaɗa kauri× 2
Girman Mould: diamita da aka faɗaɗa—2 * ganuwar da aka faɗaɗa Kauri
Juriyar diamita:
diamita＜426mm, juriya±2.5
Diamita 426-630mm, haƙuri±3
diamita＞630mm, juriya±5
Ƙarfin Juyawa:
diamita＜426mm, juriya±2
diamita＞426mm, juriya±3
Kauri:
kauri≤20mm, juriya﹢2 ，—1.5
kauri≤40mm，﹢3 ，—2
Bututun da ake buƙata don haɗa bututun
﹢5 ，—0
A ciki da waje na karce:
Zurfin gogewa: 0.2mm, tsawon: 2cm, ana kiransa karce. Ba a yarda ba
Daidaito: ≤mita 6, lanƙwasa shine 5mm，≤Tsawon mita 12, lanƙwasa shine 8mm
Misali:
Bututun asali 610*19 mai zafi wanda aka faɗaɗa 660*16
Tsawon bututun asali: mita 12.84
Faɗaɗa kauri:19*0.92=17.48(sau 1)
19*0.84=15.96(Sau 2）
Tsawon bututun da aka faɗaɗa: 610÷660*1.04*12.84=12.341962
Faɗaɗa diamita: 625+17.48*2+1=660.96(sau 1)
625+15.96*2+1=657.92(sau 2)
Girman Module: 660-2*16=628
