Hangbo Alloy Group
Shanghai · Est. 2012
Heat exchanger and condenser tubing is the most corrosion-critical, hardest-to-replace component in a plant. This guide shows why nickel alloys and copper-nickel outperform carbon steel and 304/316 stainless in seawater, sulfuric, hydrochloric, phosphoric, chloride and high-temperature process service — and how to pick the right tube for your duty.
Shell-and-tube heat exchangers and condensers move energy between two process streams, and their tubes are the thin wall that keeps those streams apart. When a tube leaks, the plant leaks — often forcing a full shutdown, bundle pull and retube. The tube material is therefore chosen for the worst credible combination of corrosion, temperature and velocity on either side, with a safety margin measured in decades, not months. Carbon steel, 304 and even 316 stainless are cheap, but they are retired early in chloride water, acid and hot process service.
This guide gives process, mechanical, marine and plant engineers a practical framework for specifying nickel-alloy and copper-nickel heat exchanger and condenser tubing. As a direct nickel alloy manufacturer and supplier, Hangbo Alloy Group produces and stocks Inconel 600/690/625, Incoloy 800H/800HT/825, Hastelloy C-276/C-22, Alloy 20/59, Monel 400 and copper-nickel 90/10 & 70/30 in seamless tube, U-tube and finned-tube forms, with mill test certificates, U-bend stress relief and third-party inspection (SGS, TÜV, BV).
Tube failure is almost always corrosion, not mechanical. Four families dominate exchanger/condenser tubing, and their behavior splits cleanly by chemistry:
Golden rule: pick the tube alloy by the dominant corrosion mechanism on the worst side (tube or shell), not by purchase price. A nickel or Cu-Ni tube that runs 20–30 years with no unplanned bundle pull almost always beats a cheap tube that leaks in 3–5 years and idles the plant.
Tube performance follows from chemistry. Nickel resists chloride SCC; chromium builds the passive film; molybdenum and tungsten blunt pitting/crevice attack; copper and iron tune acid and seawater behavior. Values are typical nominal composition ranges.
| Alloy (UNS) | Family | Ni % | Cr % | Mo % | Fe % | Cu % | Other |
|---|---|---|---|---|---|---|---|
| Inconel 600 (N06600) | Ni-Cr-Fe | ≥72 | 14–17 | — | 6–10 | — | — |
| Inconel 690 (N06690) | Ni-Cr-Fe | ≥58 | 27–31 | — | 7–11 | — | — |
| Inconel 625 (N06625) | Ni-Cr-Mo-Nb | ≥58 | 20–23 | 8–10 | ≤5 | — | Nb 3.15–4.15 |
| Incoloy 800H (N08810) | Fe-Ni-Cr | 30–35 | 19–23 | — | 39.5 min | — | Ti 0.15–0.60, Al 0.15–0.60 |
| Incoloy 825 (N08825) | Ni-Fe-Cr-Mo-Cu | 38–46 | 19.5–23.5 | 2.5–3.5 | bal. | 1.5–3.0 | Ti 0.6–1.2 |
| Hastelloy C-276 (N10276) | Ni-Cr-Mo-W | bal. | 14.5–16.5 | 15–17 | 4–7 | — | W 3–4.5 |
| Hastelloy C-22 (N06022) | Ni-Cr-Mo-W | bal. | 20–22.5 | 12.5–14.5 | 2–6 | — | W 2.5–3.5 |
| Alloy 59 (N06059) | Ni-Cr-Mo | bal. | 22–24 | 15–16.5 | ≤1.5 | — | — |
| Alloy 20 (N08020) | Fe-Ni-Cr-Mo-Cu | 32–38 | 19–21 | 2–3 | bal. | 3–4 | Nb ≤1.0 |
| Monel 400 (N04400) | Ni-Cu | 63 min | — | — | ≤2.5 | 28–34 | — |
| Cu-Ni 90/10 (C70600) | Cu-Ni-Fe | 9–11 | — | — | 1.0–1.8 | bal. | Mn ≤1.0 |
| Cu-Ni 70/30 (C71500) | Cu-Ni-Fe | 29–33 | — | — | 0.4–1.0 | bal. | Mn 0.5–1.5 |
The contrast tells the story: as the media move from seawater to acid to aggressive mixed acid, the molybdenum climbs (0 → 3% → 9% → 16%) and the nickel stays high to suppress chloride SCC. Copper-nickel trades nickel for copper to win seawater biofouling resistance at the lowest cost.
Typical room-temperature, annealed values for seamless tube product. For creep use the manufacturer's elevated-temperature stress-rupture curves; for thermal design use measured conductivity.
| Alloy | Density (g/cm³) | Tensile (MPa) | Yield 0.2% (MPa) | Elongation % | Thermal Cond. (W/m·K) |
|---|---|---|---|---|---|
| Inconel 600 | 8.47 | ≥550 | ≥240 | ≥30 | ~14.9 |
| Inconel 690 | 8.19 | ≥590 | ≥240 | ≥30 | ~12.5 |
| Inconel 625 | 8.44 | ≥830 | ≥415 | ≥30 | ~9.8 |
| Incoloy 800H | 8.0 | ≥450 | ≥180 | ≥30 | ~11.6 |
| Incoloy 825 | 8.14 | ≥550 | ≥220 | ≥30 | ~11.3 |
| Hastelloy C-276 | 8.89 | ≥790 | ≥355 | ≥40 | ~10.2 |
| Hastelloy C-22 | 8.69 | ≥690 | ≥310 | ≥40 | ~10.0 |
| Alloy 59 | 8.6 | ≥730 | ≥310 | ≥40 | ~10.0 |
| Alloy 20 | 8.08 | ≥550 | ≥240 | ≥30 | ~14.0 |
| Monel 400 | 8.8 | ≥480 | ≥170 | ≥35 | ~21.0 |
| Cu-Ni 90/10 | 8.94 | ≥310 | ≥105 | ≥35 | ~40–50 |
| Cu-Ni 70/30 | 8.95 | ≥360 | ≥125 | ≥35 | ~29–37 |
Copper-nickel conducts heat 3–4× better than the nickel alloys, which is a big reason it dominates seawater condensers where heat transfer (not corrosion margin) often sets the bundle size. For acid and high-temperature service, the nickel alloys' corrosion margin outweighs their lower conductivity.
The media decide the alloy. The summary below reflects well-established corrosion data for steady-state service; always confirm against your actual concentrations, temperature, velocity and the presence of oxidants/reducing species, and run coupon testing for new or upset duty.
| Service / Medium | Recommended Tube Alloy | Notes |
|---|---|---|
| Clean seawater condenser, ≤~3 m/s | Cu-Ni 90/10 (C70600) | Biofouling-resistant; Cr rate ~0.0025–0.025 mm/yr |
| High-velocity / polluted seawater | Cu-Ni 70/30 (C71500) / Ti | Impingement-resistant to ~4.5 m/s |
| Chlorinated / brackish seawater + process | Incoloy 825 (N08825) | Resists chloride SCC + pitting; 6Mo/AL-6XN for high Cl⁻ |
| Hot concentrated H₂SO₄ | Hastelloy C-276 / Alloy 20 | C-276 broad range; Alloy 20 cost choice |
| Dilute / aerated H₂SO₄ | Alloy 20 / Incoloy 825 | Not C-type grades |
| Hydrochloric acid (HCl) | Hastelloy C-276 / C-22 | Mo-rich Ni-Cr-Mo wins; 316/825 fail |
| Phosphoric acid (wet process) | Alloy 825 / Alloy 20 / G-30 | C-276 for aggressive; G-30 for F⁻ |
| Nitric acid (HNO₃) | Inconel 600 / 690 / 800 | Cr-rich, low/no Mo; avoid C-type & 625 |
| Hot caustic (NaOH) | Nickel 200/201 / Inconel 600 | Monel 400 also good |
| Hydrofluoric acid (HF) | Monel 400 (N04400) | Unique HF resistance; not 300SS |
| Wet Cl₂ / oxidizer + Cl⁻ | Hastelloy C-22 / Alloy 59 | High Cr + Mo |
| Refinery / petrochemical >500°C | Incoloy 800H / 800HT | Creep-rupture to ~700–800°C |
| Nuclear steam generator | Inconel 690 TT (N06690) | Resists PWSCC / SCC |
| Sour gas H₂S + Cl⁻ | Inconel 625 / 825 / 925 | NACE MR0175 / ISO 15156 |
72% Ni + 16% Cr + 8% Fe. The classic Ni-Cr-Fe tube alloy for high-purity water, nuclear primary loops (older SG), caustic and high-temperature oxidizing/neutral process streams up to ~1150°C. Excellent ductility and fabricability. Specified where chloride SCC resistance and a stable oxide in clean/high-temp service matter more than acid resistance. Supplied as seamless tube per ASTM B167 / B163.
~30% Cr, ~60% Ni. Developed to replace 600 in PWR steam generators — its much higher chromium gives outstanding resistance to primary-water stress-corrosion cracking and to secondary-side corrosion under chloride/sulfate deposits. Modern SG tubing is Inconel 690 TT (thermally treated) per ASTM B167/B163. Also used in nitric-acid and high-temperature oxidizing service.
58% Ni + 21% Cr + 9% Mo + Nb. The most versatile high-strength nickel alloy: excellent resistance to chloride pitting/crevice, seawater and sour, wet, hot process streams. The standard tube where chloride and high temperature coexist (e.g. sour effluent coolers) and a common upgrade over 825 for severe chloride. Seamless tube per ASTM B444; welded per B704/B705; condenser/HX per B163.
Fe-Ni-Cr (33% Ni + 21% Cr) with controlled Ti/Al and a controlled coarse grain size for high-temperature creep. The standard for refinery transfer lines, reactor effluent coolers, catalytic-reformer and hydrocracker exchangers from ~500°C up to ~700–800°C. Good ductility, weldable, well understood in petrochemical service. Seamless tube per ASTM B407.
40% Ni + 21% Cr + 3% Mo + 2% Cu, Ti-stabilized. The cost-effective acid+chloride workhorse: resists sulfuric and phosphoric acid, and resists chloride SCC/pitting/crevice far better than 316L in chlorinated or brackish seawater and in process streams with chlorides. Its titanium stabilization prevents sensitization during welding. The right tube where both acid and chloride are present but the duty is not aggressive enough for a C-type alloy. Seamless tube per ASTM B423 / B163.
57% Ni + 16% Cr + 16% Mo + 4% W. The benchmark for the most aggressive chemical service — HCl, hot concentrated mixed/oxidizing sulfuric, wet chlorine, ferric/cupric chlorides, organic and inorganic contaminated streams. Low carbon and balanced chemistry resist grain-boundary precipitation so it is usable as-welded. Premium cost (~8–15× carbon steel) justified where failure cost is highest. Seamless tube per ASTM B622; welded per B619/B626.
Higher-chromium (20–24%) C-type variants. C-22 adds oxidizing-acid and wet-chlorine resistance over C-276; Alloy 59 (highest Cr+Mo, near-zero iron) gives the best overall pitting/crevice resistance of the family. Specified for the harshest oxidizing + chloride service, pharmaceutical and FGD duty. Seamless tube per ASTM B622.
35% Ni + 20% Cr + 2.5% Mo + 3.5% Cu, Nb-stabilized. The economical sulfuric-acid tube — excellent in sulfuric across a broad concentration/temperature range and good in phosphoric and mildly chloride streams. Far cheaper than C-276 for non-aggressive acid. Seamless tube per ASTM B729; plate/bar per B463/B473.
Ni-Cu (63% Ni + 31% Cu). Unique resistance to hydrofluoric acid and to caustic, plus good seawater service (no chloride SCC, good velocity tolerance). Used for HF alkylation, caustic and marine/brine cooler tubes where strength and seawater + HF resistance are both needed. Seamless tube per ASTM B165 / B163.
The seawater condenser standards (ASTM B111). C70600 gives the best biofouling resistance and lowest cost, corrosion rate ~0.0025–0.025 mm/yr, design velocity up to ~3 m/s. C71500 adds strength and impingement resistance to ~4.5 m/s for polluted/high-velocity seawater. Neither suffers chloride SCC; both are readily welded and rolled into tubesheets. The lowest-cost alloy option that reliably lasts decades in seawater.
| Your Heat-Exchanger / Condenser Service | First Choice | Upgrade When… |
|---|---|---|
| Clean seawater condenser, ≤3 m/s | Cu-Ni 90/10 (C70600) | Higher velocity → Cu-Ni 70/30 |
| Polluted / high-velocity seawater | Cu-Ni 70/30 (C71500) | Max duty → Titanium |
| Chlorinated / brackish SW + process | Incoloy 825 (N08825) | Very high Cl⁻ → 6Mo / AL-6XN |
| Hot concentrated H₂SO₄ | Hastelloy C-276 / Alloy 20 | Oxidizing mixed acid → C-22 |
| Hydrochloric acid | Hastelloy C-276 (N10276) | Oxidizing HCl → C-22 / Alloy 59 |
| Phosphoric acid | Alloy 825 / Alloy 20 | Aggressive / F⁻ → C-276 / G-30 |
| Nitric acid | Inconel 600 / 690 / 800 | Cr-rich only; avoid Mo grades |
| Hot caustic (NaOH) | Nickel 200/201 / Inconel 600 | HF co-present → Monel 400 |
| Hydrofluoric acid | Monel 400 (N04400) | Fluoride salt → review with supplier |
| Refinery / petrochem >500°C | Incoloy 800H / 800HT | Wet + Cl⁻ → Inconel 625 |
| Nuclear steam generator | Inconel 690 TT (N06690) | — |
| Sour gas H₂S + Cl⁻ | Inconel 625 / 825 / 925 | NACE MR0175 / ISO 15156 |
Above ~500°C the tube is a high-temperature pressure part, and creep-rupture — not corrosion — sets the wall thickness. Two alloys dominate:
Specifying practice: size the tube to the worst-case metal temperature and the design life from stress-rupture data, then confirm the alloy resists the process chemistry at that temperature. For furnace-type radiant and pyrolysis service, see our furnace-tube selection guide (HK40/HP, Alloy 602CA).
Hangbo Alloy Group manufactures and supplies heat-exchanger and condenser tubing in the full range of mill forms, with mill test certificates and third-party inspection (SGS, TÜV, BV) available:
| Alloy (UNS / W.Nr) | Seamless Tube (HX/Cond) | Welded Tube | Plate / Bar Reference |
|---|---|---|---|
| Inconel 600 (N06600 / 2.4816) | ASTM B167 / B163 | B516 / B517 | B168 / B166 |
| Inconel 690 (N06690 / 2.4642) | ASTM B167 / B163 | B516 / B517 | B168 |
| Inconel 625 (N06625 / 2.4856) | ASTM B444 / B163 | B704 / B705 | B443 |
| Incoloy 800H (N08810 / 1.4958) | ASTM B407 / B163 | B515 / B516 | B409 / B408 |
| Incoloy 825 (N08825 / 2.4858) | ASTM B423 / B163 | B704 / B705 | B424 / B425 |
| Hastelloy C-276 (N10276 / 2.4819) | ASTM B622 | B619 / B626 | B575 / B574 |
| Hastelloy C-22 (N06022 / 2.4602) | ASTM B622 | B619 / B626 | B575 / B574 |
| Alloy 59 (N06059 / 2.4605) | ASTM B622 | B619 / B626 | B575 |
| Alloy 20 (N08020 / 2.4660) | ASTM B729 | B468 / B464 | B463 / B473 |
| Monel 400 (N04400 / 2.4360) | ASTM B165 / B163 | B165 | B127 / B164 |
| Alloy 926 / 6Mo (N08926 / 1.4529) | ASTM B677 | B674 | B625 |
| AL-6XN (N08367) | ASTM B690 | B691 | B688 |
| Cu-Ni 90/10 (C70600 / 2.0872) | ASTM B111 | B543 | B171 |
| Cu-Ni 70/30 (C71500 / 2.0882) | ASTM B111 | B543 | B171 |
All nickel and copper-nickel tube grades are also referenced by ASME SB (boiler & pressure vessel code), EN/DIN (W.Nr.), ISO, GB and JIS standards. For export projects always specify the UNS number plus the applicable ASTM/ASME SB execution standard (e.g. ASTM B163 for condenser/HX tubes, ASTM B622 for Hastelloy C-276 seamless tube). U-bends should be ordered with explicit stress-relief, hydrostatic and eddy-current inspection requirements.
Not sure whether your duty calls for Cu-Ni 90/10, Incoloy 825, Hastelloy C-276, Alloy 20, Inconel 600/690/625 or Incoloy 800H — or whether 316L will survive? Send us your tube-side and shell-side media (concentration, temperature, pressure, velocity), tube dimensions (OD, wall, length, straight vs U-bend), quantity, required standard and any third-party inspection, and our metallurgists will recommend the most cost-effective certified alloy. As a direct manufacturer and supplier, we offer competitive price quotes, full material certification, U-bend stress relief, hydrostatic and eddy-current inspection, and worldwide delivery of seamless tubes, U-tubes and finned tubes.
Email: [email protected] | Phone / WhatsApp: +86-136-1165-6360
It depends entirely on the tube-side and shell-side media. Practical defaults by service: clean seawater condensers — copper-nickel 90/10 (C70600), upgrade to 70/30 (C71500) for high velocity; chlorinated/brackish seawater with process contamination — Incoloy 825 (N08825) or a 6Mo super-austenitic (Alloy 926 / AL-6XN); hot concentrated sulfuric acid — Hastelloy C-276 (N10276) or Alloy 20 (N08020); hydrochloric acid — Hastelloy C-276 / C-22; phosphoric acid — Alloy 825, Alloy 20 or Hastelloy G-30; hot caustic or hydrofluoric acid — Inconel 600 (N06600) or Monel 400 (N04400); nuclear steam-generator tubing — Inconel 690 (N06690); refinery / high-temperature process gas above ~500°C — Incoloy 800H/800HT (N08810/N08811) or Inconel 600. Always pick by the dominant corrosion mechanism and temperature, not by name.
Carbon steel gives a few years in once-through cooling water then fails by general and under-deposit corrosion; 304 stainless pits in almost any chloride water; 316L resists mild chloride but still fails by pitting, crevice corrosion and chloride stress-corrosion cracking (SCC) in warm seawater and in acid service. Nickel alloys survive because their high nickel content resists chloride SCC, their chromium/molybdenum build a stable passive film, and grades like Hastelloy C-276 / C-22 / Alloy 59 add 15–17% molybdenum for world-class pitting and crevice resistance. The right metric is total cost of ownership: a nickel tube that runs 20–30 years with no unplanned bundle pull beats a cheap tube that leaks in 3 years and forces a plant shutdown.
For most seawater condensers the default is copper-nickel 90/10 (UNS C70600) per ASTM B111 — it gives excellent biofouling resistance, a general corrosion rate of ~0.0025–0.025 mm/year, and handles design velocities up to ~3 m/s. Where velocity is higher or water is polluted/impingement-prone, step up to copper-nickel 70/30 (UNS C71500, up to ~4.5 m/s) or titanium. Where the seawater is chlorinated/brackish or carries process contamination, or where high strength is needed, Incoloy 825 (N08825), AL-6XN (N08367) or 6Mo Alloy 926 (N08926) are specified. Monel 400 (N04400) is used where strength plus seawater and HF resistance are required. Avoid standard 316L in warm, aerated seawater because of chloride SCC.
Sulfuric acid is concentration- and temperature-dependent. For hot, concentrated and general sulfuric acid service, Hastelloy C-276 (N10276) and Alloy 20 (N08020) are the workhorses, with Incoloy 825 (N08825) a cost-effective choice for moderately concentrated, less aggressive streams. Hastelloy C-22 (N06022) and Alloy 59 (N06059) cover the most aggressive mixed/oxidizing sulfuric environments; for very dilute, aerated acid, Alloy 20 and 825 are preferred over the molybdenum-rich C-type grades. Plain sulfur dioxide / spent-acid coolers and acid-recovery exchangers almost always specify C-276 or Alloy 20. Note that chromium-only alloys (Inconel 600/690) are poor in sulfuric and are not the right choice here.
Hydrochloric acid is a strongly reducing chloride acid, so the molybdenum-rich nickel-molybdenum-chromium grades win. Hastelloy C-276 (N10276) is the standard for HCl service across broad concentration and temperature ranges; Hastelloy C-22 (N06022) and Alloy 59 (N06059) are equivalent or better in oxidizing-contaminated HCl. Nickel 200/201 resists anhydrous HCl gas but not aqueous HCl. Stainless, Incoloy and copper-nickel are not suitable for meaningful HCl service. All C-type tubes are supplied to ASTM B622 (seamless) or B619/B626 (welded).
Both are Ni-Cr-Fe alloys, but Inconel 690 (UNS N06690, ~30% Cr) was developed to replace 600 (UNS N06600, ~16% Cr) in pressurized-water-reactor steam generators because its higher chromium gives far superior resistance to primary-water stress-corrosion cracking (PWSCC) and to secondary-side denting/wastage under deposited chloride and sulfate. Modern PWR steam-generator tubing is almost exclusively Inconel 690 TT (thermally treated) per ASTM B167/B163. Inconel 600 is still widely used in non-nuclear high-purity water, alkaline and high-temperature oxidizing services. If SCC is a concern, specify 690.
Incoloy 825 (N08825) is the cost-effective workhorse for sulfuric, phosphoric and mildly chlorinated process streams, and for chlorinated seawater — its ~40% Ni + 3% Mo + 2% Cu balance resists chloride SCC, pitting and reducing acids at roughly a third of the cost of a C-type alloy. Hastelloy C-276 (N10276) or C-22 (N06022) are specified only when the media are more aggressive than 825 can handle: strong HCl, hot concentrated oxidizing/reducing mixed acids, wet chlorine, or where pitting/crevice resistance must be maximized. Choose 825 for general acid + chloride economy; choose C-276/C-22 for the harshest chemical service.
Copper-nickel 90/10 (C70600) is the standard seawater condenser and cooling-water tube: lower cost, excellent biofouling resistance, corrosion rate ~0.0025–0.025 mm/year, design velocity up to ~3 m/s. Copper-nickel 70/30 (C71500) carries more nickel, so it has higher strength and better impingement/erosion-corrosion resistance at higher velocities (up to ~4.5 m/s) and in polluted, sandy or high-turbulence seawater — at a 30–50% premium. Rule of thumb: specify 90/10 as the default; upgrade to 70/30 only when velocity, sand/impingement or pollution exceeds 90/10 limits. Both are ASTM B111 condenser tubes; neither suffers chloride SCC.
ASTM B163 is the standard specification for Seamless Nickel and Nickel-Alloy Condenser and Heat-Exchanger Tubes. It governs the dimensional, mechanical and inspection requirements (expansion/flattening, eddy-current or hydrostatic test) of the tube itself. Many nickel alloys are supplied to B163 for HX/condenser duty — Inconel 600/601/690, Incoloy 800/800H/800HT, Incoloy 825, Monel 400/401, Nickel 200/201 — while other grades use their own tube standards: B167 (Inconel 600/690), B407 (Incoloy 800), B423 (Incoloy 825), B444 (Inconel 625), B622 (Hastelloy C-276/C-22, Alloy 59), B729 (Alloy 20), B677 (Alloy 926), B111 (Cu-Ni). Always specify the UNS plus the applicable ASTM/ASME SB tube standard.
Yes for most nickel alloys. After cold bending, U-bends are stress-relieved (or fully annealed) to remove residual bending stress that would otherwise promote SCC at the bend — especially in chloride or caustic service. Typical practice: Inconel 600/690, Incoloy 800H/825 and Hastelloy tubes are stress-relieved at the alloy's specified temperature (e.g. ~800–900°C for the Ni-Cr-Fe grades) in a controlled-atmosphere furnace, then hydrostatic-tested and eddy-current inspected. Copper-nickel tubes are routinely bent and only lightly stress-relieved if needed. Specify 'U-bend + stress relief + hydrostatic test' on the purchase order, and confirm the bend radius meets the minimum for the wall thickness.
Above roughly 500°C in refinery transfer lines, reactor effluent coolers, catalytic reformer and hydrocracker services, the alloy of choice is Incoloy 800H / 800HT (UNS N08810 / N08811) per ASTM B407 — its controlled coarse grain size and Ti/Al stabilization give high creep-rupture strength to ~700–800°C. Inconel 600 (N06600) and Inconel 601 (N06601) serve high-temperature oxidizing and hydrogen-bearing process streams; Inconel 625 (N06625) is used where both chloride and high temperature coexist (e.g. sour, wet, hot effluent). For furnace-type HX and radiant service, also see HK40/HP cast and Alloy 602CA selection guides. Carbon steel and 300-series stainless are not adequate above ~450°C in these duties.
Galvanic corrosion occurs when a tube and tubesheet of different nobility are wetted by the same electrolyte. In seawater, carbon-steel tubesheets coupled to noble nickel or Cu-Ni tubes corrode preferentially; titanium tubes in a stainless tubesheet make the stainless the anode. Mitigations: (1) use a tubesheet of similar or slightly more noble material, or clad/overlay it (e.g. explode-clad Cu-Ni or nickel alloy on carbon steel); (2) roll-and-weld the tube joint so crevices are sealed; (3) apply cathodic protection or coatings in the crevice zone; (4) keep flow velocity above the stagnation threshold so deposits (which create differential-aeration cells) do not form. Hangbo Alloy can supply matched tube + tubesheet overlay material to minimize the galvanic gap.
Send us your service (tube-side and shell-side media, concentration, temperature, pressure), flow velocity, tube dimensions (OD, wall, length, straight vs U-bend), quantity, required standard (ASTM B163/B167/B407/B423/B444/B622/B729/B677/B111 or ASME SB) and any third-party inspection to Hangbo Alloy Group at [email protected] or call/WhatsApp +86-136-1165-6360. As a direct nickel alloy manufacturer and supplier we provide competitive price quotes, expert grade selection (Inconel 600/690/625, Incoloy 800H/825, Hastelloy C-276/C-22, Alloy 20/59, Monel 400, Cu-Ni 90/10 & 70/30), mill test certificates, U-bend stress relief, hydrostatic and eddy-current inspection, and worldwide delivery of seamless tubes, U-tubes and finned tubes.
For help choosing between Cu-Ni 90/10, Incoloy 825, Hastelloy C-276, Alloy 20, Inconel 600/690/625 or Incoloy 800H for your heat exchanger or condenser — or for a quotation on seamless tubes, U-tubes or finned tubes — contact Hangbo Alloy Group. We typically respond within 10 minutes and ship worldwide from our Shanghai facility.
Email: [email protected]
Phone: +86-136-1165-6360
WhatsApp: +86 13611656360
Send us your tube-side and shell-side media, temperature, pressure, velocity and tube dimensions — and we will recommend the most cost-effective certified nickel or copper-nickel alloy (Cu-Ni 90/10, Incoloy 825, Hastelloy C-276, Alloy 20, Inconel 600/690/625 or Incoloy 800H) with a competitive quote and full material certification.