ASTM A178 / ASME SA178 Grade A Carbon Steel Welded Boiler and Heat Exchanger Tube
This specification ASTM A178/ASME SA178 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. The welding process of the tube is mainly manufactured using resistance welding (ERW) technology, which is suitable for high temperature and high pressure environments.
ASTM A178 GR. A carbon steel welded boiler and heat exhcanger tubes are usually delivered in a cold worked state and require stress relief annealing (if required by the application scenario). Welding seams require 100% eddy current or ultrasonic testing to ensure no defects, and require individual water pressure testing. The pressure is calculated based on the wall thickness and diameter to ensure sealing.
ASTM A178/ ASME SA178 Chemical Composition:
| GRA. | ASTM A178/ASME SA178 CHEMICAL COMPOSITION %
|
| C | MN | P | S | Si |
| Gr.A | 0.06-0.18 | 0.27-0.63 | 0.035 | 0.035 | - |
| Gr.C | 0.035max | 0.80max | 0.035 | 0.035 | - |
| Gr.D | 0.27max | 1.00--1.50 | 0.030 | 0.015 | 0.10min |
ASTM A178 Gr.A Carbon Steel Welded Boiler and Heat Exchanger Tube Mechanical Properties
| GRADE | Tensile Strength, min ksi [MPa] | Yield Strength, min ksi [MPa] | Elongation in 2 in. or 50 mm, min, % |
|
|
| Gr.A/C/D | 47 [325] | 26 [180] | 35 |
The low carbon content of ASTM A178/ASME SA178 Gr. A carbon steel welded heat exchanger tube can improve welding performance and reduce the risk of embrittlement in the heat affected zone. At the same time, it has moderate strength and excellent plasticity, suitable for cold bending and expansion processing.
ASTM A178/ASME SA178 Gr.A Carbon Steel Welded Boiler and Heat Exchanger Tube core application areas:
(1) Boiler system
ASTM A178 Gr. A carbon steel welded tube is a commonly used material for medium and low pressure boiler tubes, especially suitable for water/steam environments with temperatures ≤ 450 ℃. Specific applications include:
- Water Walls: Located on the heating surface of the boiler furnace, they need to directly absorb radiant heat. The welding performance and plasticity of Gr. A carbon steel welded tubes can meet the processing requirements of dense tube rows.
- Economizers: Economizers use flue gas waste heat to preheat boiler feedwater, with a working temperature mainly in the low temperature range (usually<300 ℃). Gr. A carbon steel welded tubes have advantages in corrosion resistance and economy in this low temperature range.
- Steam Drum Connection Tube: In low-pressure steam cycle systems, pipelines need to withstand periodic thermal stress, which poses a risk of high fatigue and cracking. Gr.A carbon steel welded tubes have good ductility and can reduce the risk of fatigue cracking.
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ASTM A178 / ASME SA178 Grade A Carbon Steel Welded Boiler And Heat Exchanger Tube Images
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