WPC(Только для направления англ-рус! Пояснение из сайта answers: 1) WPB/WPC: first two letters mean Wrought Product, and the last letter means the pipe grade... B (35 Kpsi SMYS) and grade C (40 Kpsi SMYS). 2) WPB or WPC are a welded construction, it must have a "W" at the end, as in WPBW or WPCW. Bauirjan)
butt weld joint(Стыковой сварной шов (1,760 Google results): особенности выполнения – stalevarim.ru | The chord joint can be produced either as a butt weld joint or a fillet weld joint with a crosswise intermediate plate. The butt weld joint can be subjected to higher... Alexander Demidov)