Nickel alloys for chemical processing
Most alloy failures in a chemical plant are not general corrosion. They are pitting under a gasket, crevice attack behind a liner, or stress-corrosion cracking in a wet chloride line.
All 26 grades on this page are melted, forged and tested at our own plant in Shanghai and released with EN 10204 3.1 or 3.2 documentation. Chemistry, mechanical results and the heat number travel with the material.
Three mechanisms that decide the grade
Not a materials handbook — just the three things that most often change the answer on a real enquiry.
Reducing or oxidising, not just “acid”
Hydrochloric and sulphuric acid in a reducing environment attack nickel-molybdenum alloys quite differently from nitric acid, which is oxidising and attacks them quickly. The single most useful thing on an enquiry is which of the two you are dealing with.
Chlorides and the temperature they sit at
Pitting and crevice corrosion are driven by chloride concentration and temperature together. A grade that is generous at ambient can be the wrong choice in a 90 °C exchanger, and a gasket face is where it will show first.
Heat exchanger tube against shell
Tube and shell are frequently different alloys, because the tube side and shell side see different chemistry. Quoting both sides off one material is a false economy that shows up as a tube-sheet failure two campaigns later.
26 grades we melt for Chemical processing
Each one links to its specification page, with chemistry, standards by product form and the EN 10204 documents we issue. Showing 12 of 26.
Hastelloy C276
Inconel 690
Excellent resistance to oxidation and sulfidation at high temperatures, ideal for use in extreme heat environments.
Inconel 625
Inconel 625 exhibits strong resistance to various corrosive media, including seawater, acidic solutions, and alkaline environments.
Hastelloy G3
Excels in both oxidizing (e.g., nitric acid, hypochlorite solutions) and reducing (e.g., sulfuric acid, hydrochloric acid) environme…
904L
Excels in resisting corrosion from strong acids (e.g., sulfuric acid, phosphoric acid, acetic acid), chloride-containing media…
SMO 254
Solid-solution strengthening via alloying elements; only solution annealing needed post-fabrication.
Inconel 601
Exceptional oxidation resistance at temperatures up to 1200°C; resistant to spalling, which is beneficial during thermal cycling.
Inconel 602CA
Exceptional oxidation resistance at temperatures up to 1250°C, making it suitable for continuous service in high-heat environments.
Inconel 617
Excellent resistance to oxidation and carburization at temperatures up to 1100°C.
Monel 404
The addition of 4.00-7.00% zinc modifies the alloy’s microstructure, preventing hydrogen atoms from diffusing into the metal lattice…
321
Outstanding resistance to intergranular corrosion—titanium stabilizes carbon, avoiding chromium carbide precipitation at grain bound…
630 / 17-4PH
After precipitation hardening (aging treatment), it exhibits ultra-high tensile strength (1000-1300 MPa) and yield strength…
Three things to put on the enquiry
- Say which side of the exchanger you mean. — If tube and shell are different materials, ask for two quotes. Mixing them on one line item is how the wrong alloy ends up in the tube bundle.
- Stress relief is a chloride question, not a fabrication preference. — Austenitic stainless that is stress-relieved in the sensitisation range can come out worse than it went in for chloride service. If your fabricator plans a heat treatment, put it on the enquiry so the condition we ship matches it.
- Hydrofluoric acid is its own case. — HF service is where Monel and the low-molybdenum nickel alloys earn their place, and where a high-molybdenum grade is the wrong instinct. Tell us the acid and the concentration rather than the alloy you had in mind.
Chemical processing: questions buyers ask
The answers below are drawn from the same grade data as the tables above.
Which grade covers the widest range of chemical environments?
Hastelloy C276 is the usual starting point for mixed acid and chlorine-bearing duty, and it is the grade we would quote first when the chemistry on the enquiry is incomplete. It is the wrong answer for nitric acid, where the oxidising environment calls for Inconel 690 or 600.
Do you supply both tube and shell materials?
Yes. Seamless tube, plate, bar, strip, forgings and wire are all supplied from the same melt stream, so a tube-and-tube-sheet package can be quoted together with one document set.
What is the usual lead time?
Lead time depends on grade, form and whether the heat already exists. Send the grade, size and quantity and the quote comes back with a date, not a range.
Send the grade, the size, the quantity.
We will quote against your specification, including lead time, inspection level and documents.