SA178 Grade A / Grade C / Grade D Electric-Resistance-Welded Carbon & Carbon-Manganese Steel Tube for Heat Exchangers

Material

SA178 (equivalent to ASTM A178) is a minimum-wall-thickness electric-resistance-welded (ERW) tubing product made from carbon steel (Grade A, Grade C) and carbon-manganese steel (Grade D). It is widely specified for boiler tubes, boiler flues, superheater flues, and safe ends, and is also commonly selected for heat-transfer service where stable weld quality and consistent mechanical properties are required.

Specifications

• Manufacturing process: ERW (electric-resistance welded)

• Typical size range covered by the specification:

  • Outside diameter: 1/2" to 5" (12.7–127 mm)

  • Minimum wall thickness: 0.035" to 0.320" (0.9–9.1 mm)

• Heat treatment (key requirement): after welding, tubes shall be heat treated at 1650°F (900°C) or higher, then air-cooled (or controlled-atmosphere cooling).

• Common supply options (by order): fixed/random length, end finish (plain/beveled), surface protection (oiled / anti-rust), and inspection level (hydrostatic or NDT electric test per standard).

Main Features

• Reliable weld seam + mandatory post-weld heat treatment for uniform microstructure and stable performance at elevated temperature.

• Minimum-wall-thickness design for efficient heat transfer and responsive thermal performance in heat exchangers and boilers.

• Verified by mechanical/forming/testing requirements (tension, flattening, flange, reverse flattening, hydrostatic or nondestructive electric test).

Our Advantages 

1. “Can you guarantee weld integrity and leak-tightness?”
   Yes. SA178/ASTM A178 requires tubes to undergo flattening, flange, tension, reverse flattening, and hydrostatic (or nondestructive electric) testing—directly targeting weld soundness and pressure tightness.

2. “How do you ensure internal quality (hidden defects) for exchanger tubes?”
   In addition to standard-required testing, we can provide enhanced NDT programs. Eddy current testing (ECT) is one of the most widely used tube inspection methods for locating discontinuities in heat exchanger tubing, and can be specified when higher integrity screening is needed.

3. “Will tube surface/consistency affect heat transfer and fouling?”
   Absolutely—surface condition matters. A smoother, more uniform tube surface supports better heat transfer efficiency and can reduce fouling tendency in service. We focus on dimensional stability and surface control suitable for heat-transfer applications.

Chemical Composition (5 Reference Grades)

Mechanical Properties

Standards

• ASTM / ASME: ASTM A178/A178M (ASME SA-178/SA-178M) ERW boiler & superheater tubes.

• EN (Europe): EN 10217-1 (electric welded steel tubes for pressure purposes; delivery conditions and room-temperature properties).

• GOST (Russia/CIS): GOST 10704-91 / GOST 10705-80 (electric welded steel tubes; technical conditions).

• JIS (Japan): JIS G 3461 (carbon steel tubes for boiler and heat exchanger service).

• GB (China): GB/T 3087 (seamless steel tubes for low/medium pressure boilers), GB/T 5310 (seamless steel tubes for high pressure boilers), GB/T 3091 (welded steel pipes for low pressure fluid delivery).

Application Areas

Typical industries: power generation, petrochemical & refining, chemical processing, marine systems, district heating, industrial utilities.

Where it is used (examples):

• Shell-and-tube heat exchangers: heat transfer tube bundles (coolers, heaters, recuperators)

• Condensers & feedwater heaters: condensate cooling and heat recovery lines

• Boiler systems: water wall/economizer-related tubing, flues, and superheater-associated tube runs (when specified to SA178 scope)

Q: Are you trading company or manufacturer ?

A: manufacturer,also can do trading.

Q: How long is your delivery time?

A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,

it is according to quantity.

Q: Do you provide samples? is it free or extra ?

A: Yes, we could offer the sample for free charge but need pay the cost of freight.

Q: What is your terms of payment ?

A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.

If you have another question, pls feel free to contact with me.