API ɗin maki 5L Gr.B sun fito ne daga ƙayyadaddun API Spec 5L don bututun Layi.Standard Line bututu yana da sa nadi A da B. Ƙarfafa maki suna da nadi X bi da ƙayyadadden ƙarancin yawan ƙarfin bututun ƙarfe, wanda aka auna shi a kilopounds a kowace murabba'in inch (taƙaice ksi), misali X60 don bututu yana da ƙaramin ƙarfin amfanin gona na 60 ksi.Dubi teburin da ke ƙasa don daidaitattun maki da ake da su.
API 5L Gr.B yana rufe WELDED daBUPU MAI SAUKIdace don amfani wajen isar da iskar gas, ruwa, da mai a cikin masana'antar mai da iskar gas.
Layin Bututun Jiki
| API 5L Daraja | Ƙarfin Haɓaka min (ksi) | Ƙarfin Ƙarfin Ƙarfi min (ksi) | Bayar da Ƙaƙwalwar Ƙarfafawa (max.) | Tsawaitawa min.(%) |
| A | 30 | 48 | 0.93 | 28 |
| B | 35 | 60 | 0.93 | 23 |
| X42 | 42 | 60 | 0.93 | 23 |
| X46 | 46 | 63 | 0.93 | 22 |
| X52 | 52 | 66 | 0.93 | 21 |
| X56 | 56 | 71 | 0.93 | 19 |
| X60 | 60 | 75 | 0.93 | 19 |
| X65 | 65 | 77 | 0.93 | 18 |
| X70 | 70 | 82 | 0.93 | 17 |
| X80 | 80 | 90 | 0.93 | 16 |
Lokacin aikawa: Fabrairu-21-2020