HG/T 20615  法兰 WN 400-600 RJ&S=а Т а вВа т€™а’ТЎа Т аВв–вЗа т€™а’ТЌа Т а’Т а а†аЂт€“аЁвЛа Т а вЖа бžаВв–т€œа бžа вВа Т а’Т а а†