ASTM A178 —— Specification for electric resistance welded carbon and carbon manganese steel boiler and superheater tubes.
ASTM A178 ERW steel pipe and tube is to be used in boiler tubes, boiler flues, superheater flues and safe ends. Steel Grades A (low-carbon steel), C (medium-carbon steel), or D (carbon-manganese steel). Manufacturing processes must include heat treatment, welding after cooling. Crush test shall be performed if required by customer.
What is ASTM A 178 Grade A?
SA178A / ASTM A178 Grade A. SA178 A is an ERW (electric resistance welded) low carbon steel boiler tube used in super heaters, water wall panels, heat exchangers, condensers, marine application, refineries, paper pulping, petrochemical applications, pressure vessels, and general engineering applications.
Chemical Composition of ASTM A178 ERW Steel Pipe
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.
ASTM A178 ERW Steel Pipe Product Analysis:
1. When requested on the purchase order, a product analy- sis shall be made by the manufacturer or supplier from one tube per 100 pieces for sizes over 3 in. [76.2 mm] and one tube per 250 pieces for sizes 3 in. [76.2 mm] and under; or when tubes are identified by heat, one tube per heat shall be analyzed. The chemical composition thus determined shall conform to the requirements specified.
2. If the original test for product analysis fails, retests of two additional lengths of flat-rolled stock or tubes shall be made. Both retests, for the elements in question, shall meet the requirements of the specification; otherwise all remaining material in the heat or lot shall be rejected or, at the option of the producer, each length of flat-rolled stock or tube may be individually tested for acceptance. Lengths of flat- rolled stock or tubes which do not meet the requirements of the specifications shall be rejected.
Mechanical Properties of ASTM A178 ERW Steel Pipe
|
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 |
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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Outside diameter and Wall Thickness Tolerance of ASTM A178 ERW Steel Pipe/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% |
||
ASTM A178 ERW Steel Pipe Manufacture & Heat Treatment
The ASTM A178 Grade D steel shall be killed. ASTM A178 tubes shall be made by electric-resistance welding process. 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°F] or higher.
ASTM A178 ERW Steel Pipe Testing & Inspection
ERW tubes made from ASTM A178 steel may be tested or inspected in the following ways covering crush test, flattening test, flange test, tension test, reverse tension test, hydrostatic test, nondestructive electric test, dimension inspection, visual examination, as well as ultrasonic inspection.
ASTM A178 ERW Steel Pipe Application
ASTM A178 tubes is used in boiler, superheater, heat-exchanger and pressure equipment in Petrochemical factory, Refinery factory, sugar mill, power plant, power plant, shipbuilding.
Tips: ASTM A53 Gr.B is the grade in ERW high frequency welded pipe, divided into A and B grades. ASTM A53 Grade B is more popular than other grades. These pipes can be bare pipes without any coating, or it may be Hot-Dipped or Zinc-Coated and manufactured by Welding or by a Seamless manufacturing process. In Oil and Gas, A53 ERW grade pipes are used in the structural and non-critical applications.
