ASTM A423 Gr 1 Tubes Supplier | SA423 Corten APH Tubes

ASME SA423 Grade 1 Seamless & ERW Tubes for Air Preheaters

Dinesh Tube India supplies ASTM A423 / ASME SA423 Grade 1 tubes from Mumbai to boiler makers, power plants, air preheater (APH) and economiser fabricators, and boiler re-tubing contractors. We supply seamless and electric-resistance-welded (ERW) A423 Grade 1 tubes, and Grade 2 on request, cut to length with EN 10204 3.1 mill test certificates.

A423 Grade 1 is a copper-chromium-nickel-phosphorus low-alloy steel, the tube form of Corten weathering steel. It is chosen mainly for the cold end of tubular air preheaters, where flue gas cools towards its acid dew point and plain carbon steel tubes corrode quickly. For other Corten tube grades, see our Corten steel pipes and tubes page.

Table of Contents

What Is ASTM A423 Grade 1?
Specification
Chemical Composition
Mechanical Properties & Tests
A423 Gr 1 vs Carbon Steel APH Tubes
Common APH Tube Sizes
Applications
FAQs

What Is ASTM A423 Grade 1?

ASTM A423 / ASME SA423 covers seamless and electric-welded low-alloy steel tubes. Grade 1 contains small amounts of copper, chromium, nickel and phosphorus, the same alloying idea as Corten A weathering steel. Grade 2 is a low-phosphorus nickel-copper-molybdenum version. The standard also lists a Grade 3.

In a boiler, the coldest rows of an air preheater see flue gas near its sulphuric acid dew point. Acid condenses on the tube surface and attacks ordinary carbon steel. The copper and chromium in A423 Grade 1 slow this attack, so cold-end tubes last longer between replacements. A423 Grade 1 is still a low-alloy steel, not a stainless or acid-proof material. Tube life also depends on keeping metal temperatures above the dew point where possible, on soot blowing and on fuel sulphur.

ASTM A423 Grade 1 Corten steel tubes for air preheaters

Chemical Composition of ASTM A423 Tubes (%)

Grade	C	Mn	P	S	Si	Cu	Cr	Ni	Mo
Grade 1	0.15 max	0.55 max	0.06–0.16	0.060 max	0.10 min	0.20–0.60	0.24–1.31	0.20–0.70	–
Grade 2	0.15 max	0.50–1.00	0.04 max	0.05 max	–	0.30–1.00	–	0.40–1.10	0.10 min

Heat analysis limits. Check the current ASTM A423 / ASME SA423 edition and the mill test certificate for the governing values.

Mechanical Properties & Tests

Property	Grade 1 & Grade 2
Tensile strength, min	415 MPa (60 ksi)
Yield strength, min	255 MPa (37 ksi)
Elongation in 50 mm, min	30%
Product tests	Flattening and flaring tests; reverse flattening for ERW tubes
Leak test	Hydrostatic test or non-destructive electric test on each tube

A423 Gr 1 vs Carbon Steel APH Tubes

Point	ASTM A423 Gr 1	Carbon Steel (e.g. SA214, SA178 A)
Alloying	Cu, Cr, Ni, P	Plain C-Mn
Acid dew-point corrosion	Slower attack, longer cold-end life	Faster attack at the cold end
Typical APH position	Cold-end (low-temperature) blocks	Hot and intermediate blocks
Cost	Higher	Lower

Carbon steel APH tubes are covered on our SA214 tubes and SA178 tubes pages. For the full range, see air preheater tubes.

Common A423 Gr 1 APH Tube Sizes

OD (mm)	OD (inch)	Common Wall (mm)
38.1	1½"	2.0 – 2.6
44.5	1¾"	2.0 – 2.9
50.8	2"	2.0 – 3.2
57.0	–	2.5 – 3.5
63.5	2½"	2.6 – 3.5

Other sizes on request. Send the OD, wall, length and quantity from your APH drawing or the old tubes.

Re-tubing an air preheater? Send the grade, OD, wall, cut length, quantity and delivery location to kamlesh@dineshtube-india.com or call +91 83559 10913. You can also send an enquiry.

ASTM A423 Gr 1 Tube Applications

Cold-end blocks of tubular air preheaters
Economisers and flue-gas coolers near the dew point
Waste-heat recovery units
Coal, biomass and bagasse-fired boilers
Sugar, paper, cement and captive power plants
Thermal power station APH re-tubing

Boiler and power plant industries using A423 Grade 1 tubes

For boiler pressure parts, see boiler tubes and IBR tubes. For Corten plate used in ducts and chimneys, see Corten steel plates.

ASTM A423 Gr 1 Tubes: FAQs

What is ASTM A423 Grade 1?

ASTM A423 Grade 1 (ASME SA423 Grade 1) is a seamless or electric-welded low-alloy steel tube with small amounts of copper, chromium, nickel and phosphorus. It is the tube form of Corten-type weathering steel and is used mainly in the cold end of boiler air preheaters.

Why are A423 Grade 1 tubes used in air preheaters?

At the cold end of an air preheater, flue gas cools towards its sulphuric acid dew point and acid condenses on the tubes. Plain carbon steel corrodes quickly there. The copper and chromium in A423 Grade 1 slow this attack, so the cold-end tubes last longer between replacements.

What is the difference between A423 Grade 1 and Grade 2?

Grade 1 is a copper-chromium-nickel steel with deliberately high phosphorus (0.06–0.16%). Grade 2 has low phosphorus (0.04% max) and uses nickel, copper and molybdenum instead, with no chromium requirement. Grade 1 is the grade usually specified for Corten-type APH tubes.

Is A423 Grade 1 the same as Corten steel?

It is the tube equivalent of Corten-type weathering steel, with similar Cu-Cr-Ni-P alloying to Corten A. Corten itself is a trade name mainly used for plates and sheets, which are made to ASTM A242, A588 or EN 10025-5. Tubes for APH service are ordered to ASTM A423 / ASME SA423.

Is ASTM A423 Grade 1 stainless steel?

No. It is a low-alloy steel with roughly 1% or less of each alloying element. It resists acid dew-point and atmospheric corrosion better than carbon steel but much less than stainless steel, and it is not suitable for acid or chemical process service.

Do you supply both seamless and ERW A423 Grade 1 tubes?

Yes. We supply A423 Grade 1 in seamless and ERW forms. ERW tubes are common for large air preheater blocks; seamless tubes are used where the drawing or client specification asks for them.

What sizes are A423 Grade 1 APH tubes usually supplied in?

Common air preheater sizes are 38.1, 44.5, 50.8 and 63.5 mm OD with walls of about 2 to 3.5 mm, cut to the block length. Other sizes are available on request; send the OD, wall, length and quantity for a quote.

Which certificates come with A423 Grade 1 tubes?

Every supply comes with an EN 10204 3.1 mill test certificate showing heat number, chemical analysis, mechanical tests and the flattening, flaring and leak tests required by the standard. EN 10204 3.2 certificates and third-party inspection can be arranged on request.

Export Destinations for ASTM A423 Gr 1 Tubes

We supply A423 Grade 1 tubes to boiler makers and power plants across India and export to the Middle East (UAE, Saudi Arabia, Qatar, Oman, Kuwait), South and South-East Asia (Bangladesh, Sri Lanka, Nepal, Indonesia, Malaysia, Thailand, Vietnam, Philippines), Africa (Egypt, Nigeria, Kenya, South Africa) and other markets on request.

ASTM A423 Gr 1 Corten Steel Tubes Supplier