What are the chemical composition and mechanical properties of A179 A179M steel tube?

ASTM A179 / A179M is one of the most widely specified standards for seamless cold-drawn low-carbon steel tubes used in tubular heat exchanger tube and condenser service. For procurement engineers, EPC buyers, and fabricators, understanding the exact chemical composition and mechanical properties required by the standard is the first step toward confirming that a tube shipment will perform reliably under continuous heat-transfer duty.

This guide breaks down the composition limits, tensile and hardness requirements, dimensional ranges, and supplementary testing rules of A179 / A179M, and shows how they compare with commonly used alternatives such as A192 A192M steel tube and ASTM A210 / A210M. Whether you are sourcing condenser tube material for a new power plant, a chemical processing facility, or an HVAC system, the data below will help you specify the right product and verify the mill test certificate that arrives with it.

ASTM A179 / A179M Scope and Product Form

ASTM A179 / A179M covers minimum-wall-thickness, seamless cold-drawn low-carbon steel tubes for tubular heat exchangers, condensers, and similar heat-transfer apparatus. The current edition, A179/A179M-24, extends the outside diameter range from 1/8 in. (3.2 mm) to 3 in. (76.2 mm), inclusive, while thinner-wall and smaller-OD tubing remains commercially available but is excluded from the mandatory mechanical property tables.

Because the standard is written for cold-drawn seamless production, A179 / A179M tubes typically display a bright, smooth OD and tight dimensional tolerances. They are commonly used in:

Power plant surface condensers and feedwater heaters
Petrochemical and refinery heat-exchanger bundles
HVAC, refrigeration, and chiller condenser coils
Marine heat-transfer equipment
Industrial process coolers and evaporators

Chemical Composition Requirements

The chemical composition of A179 / A179M is intentionally simple. Only four elements are controlled in the product analysis, and any deliberate addition of alloying elements beyond these limits is not permitted. The standard specifies the following composition limits:

Element	A179 / A179M Composition, %	Function in the Steel
Carbon (C)	0.06 – 0.18	Provides basic strength while keeping weldability and formability high
Manganese (Mn)	0.27 – 0.63	Improves tensile strength and deoxidizes the melt
Phosphorus (P), max	0.035	Tight control avoids embrittlement in service
Sulfur (S), max	0.035	Keeps hot-shortness risk low during tube forming

Compared with A192 A192M (medium-carbon) or ASTM A210 (medium-carbon), the low carbon ceiling of 0.18% gives A179 / A179M better ductility and easier tube-expansion during bundle assembly. This is a key reason it is preferred for thin-wall condenser service where the tube ends are rolled into the tubesheet.

Mechanical Properties Required by the Standard

ASTM A179 / A179M sets three mechanical property values that must be met on every heat or lot, with testing conducted at room temperature. Note that these mechanical property requirements apply only to tubes 1/8 in. (3.2 mm) and larger in outside diameter and with a wall thickness of 0.015 in. (0.4 mm) or greater.

Property	A179 / A179M Requirement	Typical Mill Value
Tensile Strength, min	325 MPa (47 ksi)	340 – 380 MPa
Yield Strength, min	180 MPa (26 ksi)	200 – 240 MPa
Elongation in 2 in. (50 mm), min	35%	38 – 45%
Rockwell Hardness, max (HRB)	72	55 – 65

The combination of moderate strength and high elongation (>35%) gives A179 / A179M tubes excellent performance in tube-expansion operations. A192, in contrast, has a higher minimum tensile strength of 325 MPa and minimum yield of 180 MPa as well, but tighter wall tolerances aimed at high-pressure boiler service, so the two specifications are not interchangeable without engineering review.

Dimensional Range, Tolerances, and Wall Thickness

A179 / A179M tubes are produced in a wide size range to fit the most common tube-sheet layouts in shell-and-tube exchangers. Common size bands include:

Outside diameter: 1/8 in. (3.2 mm) to 3 in. (76.2 mm)
Wall thickness: usually 0.035 in. to 0.165 in. (0.9 – 4.2 mm), expressed in BWG (Birmingham Wire Gauge), e.g. BWG 16, 18, 20, 22, 24
Lengths: random, cut-to-length, or U-bent configurations, depending on the bundle design

Tight OD, wall, and straightness tolerances are central to the standard, because tubes must roll cleanly into the tubesheet without leak paths. Typical commercial tolerances are ±0.10 mm on OD and ±10% on wall, but tighter limits can be agreed upon at the time of enquiry. For U-bent applications, post-bend radius and leg-length controls are specified separately.

Required Tests and Inspections

To confirm that a tube meets A179 / A179M, the following tests are mandatory per lot/heat, with additional tests applied when specified by the purchaser:

Hardness test – typically Rockwell B, to confirm the tube has not been over-rolled or improperly annealed.
Flattening test – verifies ductility and weld-free soundness of the cold-drawn tube.
Flaring test – simulates tube-end expansion; the tube must flare without cracking.
Flange test – alternative to flaring for certain sizes.
Hydrostatic test – each tube is pressure-tested, or alternatively examined with a non-destructive electric test (eddy current / ultrasonic) per agreement.

A mill test certificate (MTC) issued to EN 10204 3.1 should report the actual chemical analysis, the mechanical test results, the dimensional inspection, and the NDT method used. For critical service, a 3.2 certificate with third-party witnessing (e.g. by SGS, BV, TUV) is recommended.

Comparison with Related Heat-Exchanger Tube Standards

A179 / A179M is part of a family of seamless carbon steel tube specifications. The table below summarizes the typical selection logic:

Standard	Carbon Content	Typical Use
A179 / A179M	0.06 – 0.18% (low)	Heat exchangers, condensers, low-to-medium pressure
A192 / A192M	0.06 – 0.18% (low, but tighter wall)	High-pressure boiler tubes, smoke tubes
A210 / A210M	Up to 0.35% (medium)	Boilers, superheaters, higher-temperature service

If your service is conventional shell-and-tube heat exchange with moderate temperatures and pressures, A179 / A179M is usually the most economical specification. For higher temperatures or pressure ratings, move up to A192 or A210; for corrosive media, switch to stainless stainless steel tube grades such as TP304 / TP316L.

Procurement Checklist for A179 / A179M Tubes

Before releasing a purchase order, the following points should be confirmed in writing to avoid disputes at goods-in inspection:

Standard reference and edition year (e.g. A179 / A179M-24)
OD, wall (BWG or mm), length, and quantity per size
Delivery condition: cold-drawn, annealed, or stress-relieved
NDT method: hydrostatic or eddy current / ultrasonic
MTC type: EN 10204 3.1 or 3.2, with third-party inspection if required
End finish: plain ends, beveled, or expanded for tubesheet rolling
Packaging: wooden cases, plastic end caps, and suitable protection for sea freight

A clear technical specification attached to the PO reduces the risk of receiving material that fails the final heat-exchanger hydrotest. It also speeds up the supplier's documentation review and shortens the overall delivery lead time.

How EZ Steel Industrial Supplies A179 / A179M Tubes

As a manufacturer and integrated supplier of industrial metal piping systems since 1994, EZ Steel Industrial produces A179 / A179M seamless cold-drawn low-carbon steel tubes for heat-exchanger and condenser service across the standard OD range of 1/8 in. to 3 in. (3.2 – 76.2 mm), with custom OD and wall thickness available on request. Tubes can be supplied as straight lengths or U-bent, with full traceability through heat number marking and an EN 10204 3.1 mill test certificate.

Manufacturing is supported by automated cold-drawing lines, in-line NDT (eddy current and ultrasonic), and hydrostatic testing, with more than 12 quality checkpoints from billet inspection to final packing. For projects that bundle carbon-steel heat-exchanger tubes with butt-weld pipe fittings, steel flanges, gaskets, and stud bolts, EZ Steel can consolidate the entire piping package under one delivery schedule, simplifying logistics for EPC contractors and reducing on-site coordination work.

To request a quotation for ASTM A179 / A179M tubes, send your size list, quantity, delivery condition, and required MTC type to the EZ Steel export team at export@ezsteelpipe.com. Standard sizes are usually available within 2 – 4 weeks, while custom dimensions can be scheduled based on the production calendar.

Frequently Asked Questions

Q1. Is A179 / A179M the same as A192?

No. A179 / A179M is for low-carbon steel heat-exchanger and condenser tubes, while A192 is for high-pressure boiler tubes. A192 has stricter wall-tolerance controls and is intended for higher-pressure service.

Q2. Can A179 / A179M tubes be used for boiler service?

A179 / A179M is not the preferred choice for high-pressure boilers. For boiler tubes, A192 or A210 is normally specified. A179 / A179M is mainly for heat exchangers, condensers, and similar low-to-medium pressure heat-transfer equipment.

Q3. What non-destructive test is most common for A179 / A179M?

Hydrostatic testing is the default, but eddy current testing is widely accepted as a faster alternative for mass production. Ultrasonic testing can also be specified for critical service. The chosen method must be clearly stated on the purchase order and reflected on the MTC.

Q4. What is the typical delivery condition of A179 / A179M tubes?

Most A179 / A179M tubes are supplied in the cold-drawn, hardened condition. If the tube will be heavily expanded or formed, an annealed or stress-relieved condition can be agreed upon. Surface finish is usually smooth and oiled, with plastic end caps to protect the tube interior during shipping.