20G:GB5310Karfe mai karɓuwa -95 (matakin da ya dace da ƙasashen waje: ST45.8 na Jamus, STB42 na Japan, SA106B na Amurka), shine bututun ƙarfe da aka fi amfani da shi a cikin tukunya, kayan haɗin sinadarai da halayen injiniya kuma farantin 20 iri ɗaya ne. Karfen yana da wani ƙarfi a zafin ɗaki da matsakaicin zafin jiki, ƙarancin sinadarin carbon, mafi kyawun laushi da tauri, ƙirƙirarsa mai zafi da sanyi da aikin walda yana da kyau. Ana amfani da shi galibi wajen ƙera matsi mai yawa da sigogi mafi girma na kayan aikin tukunya, babban injin dumama ƙasa, mai dumama ƙasa, mai dumama ƙasa da bangon ruwa, da sauransu. Kamar ƙaramin bututun bututu mai girman diamita ≤500℃ bututun dumama ƙasa, da bututun bango na ruwa, bututun tattalin arziki, babban bututun diamita zafin bango ≤450℃ bututun tururi, akwatin tattarawa (mai tattalin arziki, bangon ruwa, ƙaramin injin dumama ƙasa da akwatin haɗa mai dumama ƙasa), matsakaicin zafin jiki ≤450℃ kayan haɗin bututu. Domin ƙarfen carbon zai samar da graphitization a cikin aiki na dogon lokaci sama da 450℃, don haka matsakaicin zafin aiki na dogon lokaci na bututun saman dumama ya fi dacewa a iyakance shi zuwa ƙasa da 450℃. Karfe a cikin wannan kewayon zafin jiki, ƙarfinsa zai iya biyan buƙatun bututun zafi da tururi, kuma yana da juriya mai kyau ga iskar shaka, laushi, tauri, halayen walda da sauran kaddarorin sarrafawa na sanyi da zafi suna da kyau sosai, ana amfani da su sosai. Sassan ƙarfen da ake amfani da su a cikin tanderun Iran (yana nufin saiti ɗaya) sune bututun shigar ruwa (tan 28), bututun shigar ruwa (tan 20), bututun haɗa tururi (tan 26), kwantena mai tattalin arziki (tan 8), da tsarin rage ruwa (tan 5), sauran kuma ana amfani da su azaman kayan ƙarfe mai faɗi da kayan derrick (kimanin tan 86).

Sa-210c (25MnG): Lambar ƙarfe a cikiASME SA-210Daidaitacce. Ƙaramin bututu ne mai diamita na ƙarfen carbon manganese don tukunyar ruwa da na'urorin dumama ruwa, da kuma ƙarfe mai ƙarfi mai siffar lu'u-lu'u. A shekarar 1995, an dasa shi zuwa GB5310 kuma aka sanya masa suna 25MnG. Haɗin sinadarai yana da sauƙi, sai dai yawan sinadarin carbon da manganese, sauran yana kama da 20G, don haka ƙarfin amfani yana da kusan kashi 20% sama da 20G, kuma filastik da tauri suna kama da 20G. Tsarin samar da ƙarfe yana da sauƙi kuma aikinsa na sanyi da zafi yana da kyau. Amfani da shi maimakon 20G, zai iya rage kauri na bango, rage adadin kayan aiki, amma kuma yana iya inganta canja wurin zafi na tukunyar. Sassan amfani da shi da zafin amfani da shi iri ɗaya ne da 20G, galibi ana amfani da shi don zafin aiki a ƙasa da bangon ruwa na 500℃, mai tsara tattalin arziki, mai dumama zafi mai ƙarancin zafi da sauran abubuwan haɗin.
Sa-106c: Lambar ƙarfe ce a cikinASME SA-106Daidaitacce. Bututun ƙarfe ne na carbon-manganese don tukunyar dumama mai girman girma da kuma na'urorin dumama mai zafi. Haɗin sinadarai yana da sauƙi, kamar ƙarfen carbon 20G, amma abun da ke cikin carbon da manganese ya fi girma, don haka ƙarfin fitarwarsa ya fi 20G girma da kusan 12%, kuma ƙarfin filastik ɗin ba shi da muni. Tsarin samar da ƙarfen yana da sauƙi kuma aikinsa na sanyi da zafi yana da kyau. Yin amfani da shi maimakon mai tattara masana'antu na 20G (mai tattalin arziki, bangon sanyaya ruwa, na'urar dumama mai ƙarancin zafi da akwatin haɗa zafi), kauri na bango zai iya raguwa da kusan 10%, wanda ba wai kawai zai iya adana farashin kayan ba, har ma yana rage nauyin walda, da kuma inganta bambancin damuwa lokacin da akwatin haɗa ya fara.
15Mo3 (15MoG) : Bututun ƙarfe ne a ma'aunin DIN17175. Bututun ƙarfe ne mai ƙaramin diamita na carbon molybdenum don tukunyar jirgi da kuma babban zafi, da kuma ƙarfe mai ƙarfi irin na pearlescent. A shekarar 1995, an dasa shi zuwa GB5310 kuma aka sanya masa suna 15MoG. Haɗin sinadarai yana da sauƙi, amma yana ɗauke da molybdenum, don haka yana da ƙarfin zafi mafi kyau fiye da ƙarfen carbon yayin da yake riƙe da aikin tsari iri ɗaya da ƙarfen carbon. Saboda kyakkyawan aikinsa, farashi mai rahusa, an yi amfani da shi sosai a duniya. Duk da haka, ƙarfen yana da halin yin graphitization bayan aiki na dogon lokaci a babban zafi, don haka ya kamata a sarrafa zafin aikinsa ƙasa da 510℃, kuma adadin Al da aka ƙara a cikin narkewa ya kamata a iyakance shi don sarrafawa da jinkirta aikin graphitization. Wannan bututun ƙarfe galibi ana amfani da shi don ƙaramin zafi da ƙaramin zafi. Zafin bango yana ƙasa da 510℃. Sinadarin sa C0.12-0.20, SI0.10-0.35, MN0.40-0.80, S≤0.035, P≤0.035, MO0.25-0.35; Matsayin ƙarfi na yau da kullun σs≥270-285, σb≥450-600 MPa; Plastic delta 22 ko sama da haka.