Da'irar ƙirƙirana wani nau'i ne na ƙirƙira, a gaskiya, a sanya shi a sauƙaƙe, shi neƙirƙirana zagaye karfe.
Ƙirƙirar da'iroriBabu shakka sun bambanta da sauran karafa a masana'antu, kuma za'a iya raba da'ira na jabu zuwa kashi uku, amma mutane da yawa ba su da wata fahimta ta musamman.ƙirƙira da'irori, don haka bari mu fahimci dacewa ilimin da'irori da aka yi tare, domin mu sami mafi fahimtar masana'antu.
jabuda'irar karfe ce mai zagaye da aka kirkira bisa ga bukatun fasaha. Ƙayyadaddun ƙayyadaddun kayan aikin gida na iya isa diamita 1500mm. An ƙirƙira kayan ƙirƙira don danna ƙarfin tasiri, dacewa da ƙananan sassa ko sarrafa ƙarfe na musamman.
Ƙarfe mai zagaye yana nufin ƙwanƙarar tsiri na karfe tare da sashin zagaye. An bayyana ƙayyadaddun sa a cikin adadin millimeters a diamita, kamar "50" wato, diamita na 50 mm zagaye karfe.
An raba karfen zagaye zuwa nadi mai zafi, na jabu da sanyi. Ƙayyadaddun ƙayyadaddun zafi mai birgima zagaye karfe shine 5.5-250 mm. Daga cikin su: 5.5-25mm ƙananan karfe zagaye yawanci ana ba da su a cikin madaidaicin daure, wanda aka saba amfani dashi don ƙarfafa sanduna, kusoshi da sassa daban-daban na inji; Karfe zagaye da ya fi mm 25, ana amfani da shi musamman wajen kera sassan injina ko a matsayin fanko don bututun ƙarfe maras sumul.