ASTM A178 Grade C Electric-resistance-welded carbon steel Medium-Carbon Steel Boiler and Superheater Tubes
ASTM A178 specification covers minimum-wall-thickness,electric-resistance-welded tubes made of carbon steel and carbon-manganese steel intended for use as boiler tubes, boiler flues, superheater flues, and safe ends.
ASTM A178 Grade C Boiler and Superheater Tubes are not suitable for safe-ending for forge welding.
ASTM A178 Grade C Boiler and Superheater Tubes Quick Details
Outside Diameter ：12.7mm-127mm
Length：6000mm、12000m or specified length as required.
Type of End-Finish：Plain End、Beveled End、Treaded
Surface treatment: Tubes will be varnished (Outside only) to prevent rust.
ASTM A178 Grade C Boiler and Superheater Tubes sizes and thicknesses usually furnished to this specification are 1 ⁄ 2 to 5 in. [12.7 to 127 mm] in outside diameter and 0.035 to 0.360 in. [0.9 to 9.1 mm], inclusive, in minimum wall thickness. Tubing having other dimensions may be furnished, provided such tubes comply with all other requirements of this specification.
Tubes shall be made by electric-resistance welding.
After welding, all tubes shall be heat treated at a temperature of 1650°F [900°C] or higher and followed by cooling in air or in the cooling chamber of a controlled-atmosphere furnace. Cold-drawn tubes shall be heat treated after the final cold-draw pass at a temperature of 1200°F[650°C] or higher.
|Grade C, Medium-
|Tensile strength, min, ksi [MPa]
|Yield strength, min, ksi [MPa]
|Elongation in 2 in. or 50 mm, min, %
|For longitudinal strip tests a deduction for each 1 ⁄ 32 -in. [0.8 mm] decrease in wall thickness below 5 ⁄ 16
in. [8 mm] from the basic minimum elongation of the
following percentage points shall be made.
Mechanical property requirements do not apply to tubing smaller than 1 ⁄ 8 in. [3.2 mm] in inside diameter or 0.015 in. [0.4 mm] in thickness
Mechanical Tests Required
Reverse Flattening Test
Hydrostatic or Nondestructive Electric Test
When inserted in the boiler, tubes shall withstand expanding and beading without showing cracks or flaws, or opening at the weld. When properly manipulated, superheater tubes shall withstand all forging, welding, and bending operations necessary for application without developing defects.