| 7304.29.20 | 30 | Having an outside diameter of 215.9 mm or more but not exceeding 285.8 mm: | | | | |
| 7304.29.20 | 40 | Having a wall thickness of 12.7 mm or more | kg | | | |
| 7304.29.20 | 60 | Having a wall thickness of 12.7 mm or more | kg | | | |
| 7304.29.31 | 20 | Having a wall thickness of 12.7 mm or more | kg | | | |
| 7304.29.31 | 30 | Having an outside diameter of 215.9 mm or more but not exceeding 285.8 mm: | | | | |
| 7304.29.31 | 40 | Having a wall thickness of 12.7 mm or more | kg | | | |
| 7304.29.31 | 60 | Having a wall thickness of 12.7 mm or more | kg | | | |
| 7304.29.31 | | Of other alloy steel: | | | | |
| 7304.29.41 | 20 | Having a wall thickness of 12.7 mm or more | kg | | | |
| 7304.29.41 | 30 | Having an outside diameter of 215.9 mm or more but not exceeding 285.8 mm: | | | | |
| 7304.29.41 | 40 | Having a wall thickness of 12.7 mm or more | kg | | | |
| 7304.29.41 | 60 | Having a wall thickness of 12.7 mm or more | kg | | | |
| 7304.29.50 | | Of iron or nonalloy steel | | Free | | 25% |
| 7304.29.50 | 60 | Having an outside diameter of 215.9 mm or more but not exceeding 406.4 mm | kg | | | |
| 7304.29.61 | | Of other alloy steel | | Free | | 35% |
| 7304.29.61 | 60 | Having an outside diameter of 215.9 mm or more but not exceeding 406.4 mm | kg | | | |
| 7304.31 | | Other, of circular cross section, of iron or nonalloy steel: | | | | |
| 7304.31.60 | 10 | Suitable for use in boilers, superheaters, heat exchangers, condensers, refining furnaces and feedwater heaters | kg | | | |
| 7304.39.00 | 02 | Suitable for use in boilers, superheaters, heat exchangers, condensers, refining furnaces and feedwater heaters: | | | | |
| 7304.39.00 | 04 | Having an outside diameter of 38.1 mm or more but less than 190.5 mm | kg | | | |
| 7304.39.00 | 06 | Having an outside diameter of 190.5 mm or more but not exceeding 285.8 mm | kg | | | |
| 7304.39.00 | 68 | Having a wall thickness of 12.7 mm or more but less than 19 mm | kg | | | |
| 7304.39.00 | 72 | Having a wall thickness of 19 mm or more | kg | | | |
| 7304.39.00 | 80 | Having a wall thickness of 19 mm or more | kg | | | |
| 7304.39.00 | 24 | Having an outside diameter of 38.1 mm or more but not exceeding 114.3 mm: | | | | |
