Reducer: 大小头.
BLIND HUB: 盲管.
FLANGE BLIND: 盲法兰.

下面都是标准:
DIN-2616-2-E-114.3*3.6-88.9-3.2 W-A
ASME B16.5 CLASS 2500#
2500#RTJ ASME B16.5 ASTM A105N

ASME: American Society of Mechanical Engineers
ASME B16.5: Pipe flanges and flanged fittin

ASTM: American Society for Testing and Materials
ASTM A105N: Forged Steel Fittings

谢谢解答