ASTM A178 is a standard specification for electric-resistance-welded (ERW) tubes made from carbon steel and carbon-manganese steel. These tubes are primarily used in boilers, superheaters, and heat exchangers, where they must withstand high temperatures and pressures. The specification outlines the requirements for manufacturing, chemical composition, mechanical properties, and testing, ensuring the tubes perform effectively in demanding applications.
Usage：Used in boiler, superheater, heat-exchanger and pressure equipment in Petrochemical factory, Refinery factory, sugar mill, power plant, power plant, shipbuilding.
Outside diameter and Wall Thickness Tolerance of ASTM A178 welded boiler tube
|
Outside Diameter tol |
Wall thickness tol |
||
|
OD < 50 |
±0.05mm |
S < 4mm |
±12.5% |
|
OD > 50 |
±1% |
4--20mm |
+15/-12.5% |
|
S≧20mm |
±12.5% |
||
Chemical Composition of ASTM A178
|
Element % |
ASTM A178 Gr A / SA178A |
ASTM A178 Gr C / SA178C |
ASTM A178 Gr D / SA178D |
|
Low carbon steel |
Medium Carbon Steel |
Manganess Steel |
|
|
C |
0.06-0.18 |
0.35 Max |
0.27 Max |
|
Mn |
0.27-0.63 |
0.80 Max |
1.00-1.50 |
|
P |
0.035 |
0.035 |
0.030 |
|
S |
0.035 |
0.035 |
0.015 |
|
Si |
... |
... |
0.10 Min. |
Mechanical Property
|
Item |
ASTM A178 Gr A / SA178A |
ASTM A178 Gr C / SA178C |
ASTM A178 Gr D / SA178D |
|
Tensile strength, min, ksi [MPa] |
47[325] |
60[415] |
70[485] |
|
Yield strength, min, ksi [MPa] |
26[180] |
37[255] |
40[275] |
|
Elongation in 2 in. or 50mm, min, % |
35 |
30 |
30 |
|
For longitudinal strip tests a deduction for |
1.50A |
1.50A |
1.50A |
|
Each1⁄32-in[0.8mm] decrease in wall thickness below 5⁄16in. [8mm] |
|
|
|
|
From the basic minimum elongation of the following percentage points shall be made |
|
|
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