ASTM A423 Grade 2 Low-Alloy Steel Tubes
ASTM A423 Grade 2 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.
Description
ASTM A423 Grade 2 Seanmless And Electric-Welded Low-Alloy Steel Tubes
Standard：ASTM A423/A423M
Standard Specification for Seanmless And Electric-Welded Low-Alloy Steel Tubes
ASTM A423 Grade 2 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 2 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.
Manufacture
ASTM A423 Grade 2 Low-Alloy Steel Tubes made by the seamless process may be hot finished or cold finished.
Heat Treatment
ASTM A423 Grade 2 Low-Alloy Steel Tubes shall be normalized or given such heal treatment
Chemical Composition
| Carbon, max | 0.15 |
| Manganese | 0.50-1.00 |
| Phosphorus | 0.04 max |
| Sullur. max | 0.05 |
| Silicon | …. |
| Copper | 0.30-1.00 |
| Chromium | …. |
| Nickel | 0.40-1.10 |
| Molybdenum | 0.10 min |
| Antimony | …. |
Mechanical Properties
| Grades 2 | |
| Tensile strength, min. ksi | 60[415] |
| Yield strength, min, ksi [MPa] | 37[255] |
| Elongation in 2 in. or 50 mm. min, % | 25 |
| 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 | 1.25 A |
| Hardness | 170 HB |
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
Forming Operations
Tubes when inserted in the boiler shall stand expanding and beading without showing cracks or flaws.
Mechanical Tests Required
1.1 Tension Test—One tension test shall be made on a specimen for lots of not more than 50 tubes.Tension tests shall be made on specimens from two tubes for lots of more than 50 tubes
1.2 Flattening Test—One flattening test shall be made on specimens from each end of one flnished tube, not the one used for the flaring or flanging test, from each lot
1.3 Flaring Test (Seamless Tubes)—One flaring test shall be made on specimens from each end of one finished tube, not the one used for the flattening test, from each lot
1.4 Flange Test (Welded Tubes)—One flange test shall be made on specimens from each end of one finished tube, not the one used for the flattening test, from each lot
1.5 Hardness Test—Brinell or Rockwell hardness tests shall be made on specimens from two lubes from each lot
1.6 Reverse Flattening Test—Kor welded tubes, one reverse flattening test shall be made on a specimen from each 1500 ft [460 m] of finished tubing.
1.7 Hydrostatic or Nondestructive Electric Test—Each tube shall be subjected to the hydrostatic test.