ASTM A423 Grade 3 Low-Alloy Steel Tubes
Standard Specification for Seanmless And Electric-Welded Low-Alloy Steel Tubes
ASTM A423 Grade 3 Steel Tubes covers minimum-wall-thickness, seamless and electric-resistance welded, low-alloy steel tubes for pressure containing parts such as economizers or other applications where corrosion resistance is important.
ASTM A423 Grade 3 Low-Alloy Steel 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 0.500 in.[0.9 to 12.7 mm] inclusive, in minimum wall thickness.
ASTM A423 Grade 3 Low-Alloy Steel Tubes made by the seamless process may be hot finished or cold finished.
ASTM A423 Grade 3 Low-Alloy Steel Tubes shall be normalized or given such heal treatment
|Tensile strength, min. ksi
|Yield strength, min, ksi [MPa]
|Elongation in 2 in. or 50 mm. min, %
|For longitudinal strip tests a deduction for each 1/32 in.[0.6 mm] decrease in wall thickness below 5/16in. [8 mm] from the basic minimum elongation of the following percentage points shall be made
A Calculated elongation requirements shall be rounded to the nearest whole number.
NOTE: Mechanical property requirements do not apply to tubing smaller than 1/4 in.[3.2 mm] in inside diameter or 0.015 in.[0.4 mm] in thickness
Tubes when inserted in the boiler shall stand expanding and beading without showing cracks or flaws.
Mechanical Tests Required
Flaring Test (Seamless Tubes)
Flange Test (Welded Tubes)
Reverse Flattening Test
Hydrostatic or Nondestructive Electric Test