... Tianjin Beichen District, near one of the biggest steel pipe manufacturing based in China-Daqiuzhuang. Our total ... , fluid pipes, boiler pipes, high pressure pipes, steel plate, steel coils, chemical fertilizer pipes, flanges and elbows. As ... we only keep a very thin margin. Name: square welded steel tube Standard: GB/T6728-2002, ASTM A500, JIS ... to do business with you. Q235 square steel welded tube