What is the difference between A179 A179M steel tube and A213 stainless tubes?

When a heat exchanger, condenser, or boiler feed system is being engineered, two ASTM specifications keep coming up on the sourcing sheet: A179/A179M steel tube and A213/A213M steel tube. On a quotation they look similar—small-diameter seamless tubing for thermal service—but they are designed for very different jobs. Choosing the wrong one usually shows up later as accelerated corrosion, creep cracking, or a tube bundle that has to be replaced far earlier than planned.

This guide walks through how the two specifications differ in scope, material, mechanical properties, temperature range, and typical application, and explains how EZ Steel Industrial produces both families of tubes for industrial buyers.

1. What Each Specification Actually Covers

ASTM A179/A179M is a single-grade specification. It covers seamless cold-drawn low-carbon steel tubes used in tubular heat exchangers, condensers, and similar heat-transfer apparatus. The chemistry is intentionally simple—carbon, manganese, phosphorus, and sulfur—so the steel is easy to form, easy to weld, and economical to buy in long mill runs.

ASTM A213/A213M is a much broader family. It covers seamless ferritic and austenitic alloy-steel boiler, superheater, and heat-exchanger tubes, designated by grades such as T2, T11, T22, T91, T92 on the ferritic side and TP304, TP304H, TP316, TP316H, TP321, TP347H on the austenitic side. Each grade is a different alloy package designed for a different combination of temperature, pressure, and corrosion.

In short: A179 is one product made one way; A213 is a whole family of products covering a wide performance envelope.

2. Material Family and Chemical Make-Up

A179 sits firmly in the plain carbon-steel category. Carbon is typically held to about 0.06–0.18 %, manganese around 0.27–0.63 %, with tight limits on phosphorus and sulfur. There is no deliberate addition of chromium, molybdenum, or nickel for corrosion or creep resistance.

A213 grades, by contrast, rely on alloying. Ferritic grades use chromium and molybdenum (1–9 % Cr, 0.5–1 % Mo) to build creep strength; austenitic grades use 18 % Cr + 8 % Ni as a base, with extra molybdenum in TP316 for chloride resistance and titanium or niobium in TP321/TP347H for high-temperature stability. The chemical envelope is what gives A213 its performance ceiling.

3. Mechanical Properties Side by Side

Looking at minimum tensile and yield values, the two specifications are not dramatically different in raw numbers—but they are designed for different duty cycles.

A179 sets a tensile strength minimum of 325 MPa and a yield minimum of 180 MPa, with elongation of 35 % minimum. Hardness is capped at 163 HBW. A213 ferritic grades such as T11 and T22 lift tensile strength to 415 MPa and yield to 205 MPa; T91 pushes tensile to 585 MPa and yield to 415 MPa for ultra-supercritical service. Austenitic grades such as TP304 require 515 MPa tensile and 205 MPa yield; TP316L keeps 485 MPa tensile and 170 MPa yield, all with 35 % minimum elongation.

What those numbers really say is that A179 is engineered for stable heat transfer in moderate conditions, while A213 grades are engineered to hold shape and strength while internal pressure and metal temperature climb.

4. Temperature and Pressure Envelope

A179 tubes are normally used on the cooler side of the heat-transfer envelope—low- to medium-temperature condensers, feedwater heaters, and process coolers where the metal temperature typically stays around 400 °C or below. Their strength and oxidation resistance ｄｒｏｐ quickly above that point.

A213 was built to go much further. Ferritic grades such as T11 and T22 are common up to about 540 °C; T91 extends service to 650 °C in supercritical and ultra-supercritical boilers. Austenitic stainless grades such as TP304H, TP321, and TP347H can run even higher when the system is designed for them. Because of this, A213 is the default specification for boiler walls, superheater panels, and high-pressure steam piping.

5. Corrosion and Creep Behavior

Plain low-carbon steel such as A179 has limited corrosion resistance. It performs well in clean water, glycol, low-pressure steam, and mild process fluids, but in seawater, acidic condensates, or chloride-bearing streams the life of an A179 tube can be short.

A213 changes that picture. Ferritic Cr-Mo grades resist oxidation and sulfide attack in refinery and power-plant service. Austenitic TP304 and TP316 offer true stainless corrosion performance; TP316, with 2–3 % Mo, holds up against chlorides and many organic acids, which is why it is widely used in chemical and marine heat exchangers. Above ~540 °C, creep becomes the controlling factor—and that is where the higher alloy A213 grades, with their added Cr, Mo, and V, outperform plain carbon steel by a wide margin.

6. Manufacturing and Inspection

Both specifications require seamless construction, but the route differs. A179 is made as cold-drawn seamless tubing, which produces a smooth inner surface, tight dimensional tolerances, and thin walls suitable for compact bundles. A213 is typically hot-finished or cold-drawn, depending on the grade and size, with full solution anneal or normalize-and-temper heat treatment for stainless and Cr-Mo grades.

Mandatory tests also differ in scope. A179 calls for tension, flattening, flaring, and hardness testing plus a non-destructive electric or hydrostatic test. A213 adds hardness limits per grade, more detailed grain-size and microstructure requirements for stainless grades, and stricter NDT criteria for high-temperature service. EN 10204 3.1 mill test certificates are commonly requested by buyers for A213.

7. Application Map

A179 is the right answer when the duty is heat transfer at moderate temperature and the fluid is reasonably clean. Typical uses include:

Shell-and-tube condensers in power stations and HVAC systems
Low-pressure feedwater heaters and oil coolers
Industrial process coolers handling fresh water, glycol, or neutral chemicals
Economizer sections where the metal temperature stays modest

A213 covers a much wider industrial footprint:

Boiler tubes and superheater panels in thermal and ultra-supercritical power plants (T11, T22, T91, T92)
Refinery furnace tubes, hydrocracker reactors, and high-pressure steam lines (T11, T22, TP304H, TP347H)
Heat exchangers and process coolers in chemical, petrochemical, and pharmaceutical plants (TP304, TP316L)
Marine and offshore heat exchangers using seawater or brackish water on the shell side (TP316, TP316L)
U-bend and finned tube bundles for high-efficiency heat recovery (TP304, TP316, T11)

8. How to Choose Between Them

A practical selection starts with four questions:

What is the maximum metal temperature during continuous operation? Below ~400 °C and with a clean fluid, A179 is usually the most cost-effective choice. Above that line, A213 grades take over.
How aggressive is the fluid on the tube side? If the working fluid is neutral water, glycol, or low-pressure steam, A179 will give a long service life. If the fluid contains chlorides, acids, sulfides, or organics, switch to an A213 stainless grade such as TP316L.
What pressure class is the bundle designed for? Both specifications are seamless, but A213 ferritic and austenitic grades offer higher allowable stress at temperature, which can translate to thinner walls or smaller diameters at the same design pressure.
What codes govern the project? ASME Section I (power boilers), Section VIII (pressure vessels), and Section III (nuclear) frequently call out A213 grades by name for elevated-temperature service. Following the code first often resolves the choice.

A simple rule of thumb: choose A179 when the goal is efficient heat transfer at low cost in a clean system. Choose A213 when temperature, pressure, or corrosion start pushing the limits of carbon steel.

9. Sourcing Both Grades from One Supplier

Because the two specifications sit on the same shop floor—seamless cold-drawn and hot-finished lines, heat-treatment furnaces, hydrostatic benches, and NDT stations—buyers benefit from sourcing them together. EZ Steel Industrial produces ASTM A179/A179M seamless low-carbon steel tubes for condensers and ASTM A213/A213M tubes in TP304H, TP316H, T11, T22, T91 and related grades for boilers and high-temperature heat exchangers. Manufacturing runs across the Cangzhou, Yangzhou, and Lishui facilities, with more than twelve in-line quality checkpoints covering chemistry, dimensions, mechanical testing, and non-destructive examination.

For projects that mix condenser and boiler sections, this combination matters: the mill test certificates, traceability codes, and packaging conventions are consistent, which simplifies incoming inspection and project documentation.

10. Practical Takeaways

A179 = seamless cold-drawn low-carbon steel, for clean, low- to medium-temperature heat-transfer service, with a 325 MPa tensile minimum.
A213 = seamless ferritic and austenitic alloy-steel family, with grades covering everything from 540 °C boilers (T11, T22) to 650 °C ultra-supercritical units (T91) and corrosive chemical service (TP304, TP316).
The right choice is driven by metal temperature, fluid corrosiveness, design pressure, and the governing code—not by the appearance of the tube.
When both grades are needed in the same project, consolidating supply with a manufacturer that produces both simplifies QA, documentation, and delivery.

If you are sizing a new heat-exchanger bundle or upgrading an existing boiler and need help mapping temperature, pressure, and fluid conditions to the correct ASTM grade, the EZ Steel Industrial engineering team can review your specification and recommend the right tube—A179, A213, or a hybrid bundle—at ezindustrialtube.com.