ASME SA179 Carbon Steel Seamless Tube Low Carbon Steel U Bend Heat Exchanger Tube
ASTM A179 / ASME SA179 Carbon Steel Heat Exchanger Tube Seamless Steel U Bend Tube
ASME SA179 carbon steel seamless U-bend tubes are used in roughly 60–70% of all carbon steel shell-and-tube heat exchangers globally.
In the petrochemical, refinery, and power generation sectors, if the operating environment is non-corrosive or mildly corrosive and temperatures are below 400°C, SA179 is the default "workhorse" choice. Its high ductility (minimum elongation of 35%) allows it to be cold-bent into a tight 1.5D radius without cracking—something higher-strength carbon steels struggle with. So, SA179 is used because it bends reliably, not because it is the strongest.
Chemical Composition % of ASME SA179 Carbon Steel Seamless Tube U Bend Heat Exchanger Tube
| Element % | C | Mn | P | S |
| 0.06-0.18 | 0.27-0.63 | 0.035 | 0.04 |
Material Mechanical Properties of ASTM A179 / ASME SA 179 Carbon Steel Seamless Tube
| Yield Strength(MPa) | Tensil Strength(MPa) | Elogation(%) |
| ≥180 | ≥325 | ≥35 |
Comparison with Similar Grades
| Grade | Standard | Key Difference |
|---|---|---|
| SA179 | ASME | Cold-drawn, mandatory heat treatment, fine grain, higher ductility. |
| SA192 | ASME | Higher carbon (0.06–0.18% C), higher tensile (≥55 ksi), for boilers. |
| SA210 A1 | ASME | Medium-carbon steel (C ≤0.27%), higher strength, for boiler tubes. |
| EN 10216-2 P195 | EN | Similar low-carbon seamless, slightly different mechanicals. |
| JIS G3461 STB340 | JIS | Japanese equivalent; comparable properties. |
Some clients require SSC and HIC tests for SA179 carbon steel tubes. Core reasons:
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Work-hardening at the bend – Cold bending raises the outer radius hardness above sour-service limits (NACE MR0175). SSC testing forces the mill to prove their post-bend heat treatment actually softens the bend apex, not just the straight legs.
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Steel cleanliness – SA179 has no mandatory inclusion control. HIC testing forces the steelmaker to use ultra-low-sulfur, calcium-treated steel so elongated MnS inclusions don't open into hydrogen-trapping voids during bending.
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Surface damage – Scratches from worn bending mandrels create stress-raisers. Testing finished bent coupons catches these defects that straight-tube MTRs never reveal.
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Heat treatment verification – Passing SSC/HIC proves the mill performed a full normalizing after bending, not just a cheap local stress-relief that leaves a vulnerable microstructure.
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Feedwater Heaters (Power Generation)
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Heat Exchanger
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HVAC Chillers and Condensers (Comfort & Process Cooling)
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Industrial Intercoolers and Aftercoolers
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Marine Engineering
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