变径弯头常用材质：
碳钢: ASTM/ASME A234 WPB、WPC
合金: ASTM/ASME A234 WP 1-WP 12-WP 11-WP 22-WP 5-WP 91-WP911、15Mo3 15CrMoV、 35CrMoV
不锈钢:ASTM/ASME A403 WP 304-304L-304H-304LN-304N
ASTM/ASME A403 WP 316-316L-316H-316LN-316N-316Ti
ASTM/ASME A403 WP 321-321H ASTM/ASME A403 WP 347-347H
低温钢:ASTM/ASME A402 WPL3-WPL 6
高性能钢: ASTM/ASME A860 WPHY 42-46-52-60-65-70
