Hastelloy B3 and Hastelloy C276 are nickel-based corrosion-resistant alloys, but they are designed for different chemical environments. B3 is principally selected for strongly reducing media, while C276 provides broader resistance across reducing and oxidizing conditions. Choosing between them requires more than comparing nominal nickel content.
Hastelloy B3 vs C276 Overview
| Factor | Hastelloy B3 | Hastelloy C276 |
|---|---|---|
| UNS | N10675 | N10276 |
| Alloy family | Nickel-molybdenum | Nickel-chromium-molybdenum-tungsten |
| Selection strength | Reducing acids | Broad mixed chemical service |
| Oxidizing media | Generally unsuitable without detailed review | Better tolerance in many oxidizing or contaminated systems |
Why Hastelloy B3 Performs in Reducing Acids
B3 contains high nickel and molybdenum with very low chromium. This chemistry supports resistance to hydrochloric acid and other reducing environments over useful concentration and temperature ranges. Compared with earlier B-family alloys, B3 was developed with improved thermal stability and fabrication behavior. It may be considered for reactors, piping, valves, pumps and heat exchangers handling reducing chemicals.
The same low chromium content limits resistance when oxidizing species are present. Ferric ions, cupric ions, dissolved oxygen or other oxidants can change corrosion behavior significantly. Process contamination and cleaning chemicals must therefore be included in the materials review.
Why C276 Covers More Process Conditions
C276 combines molybdenum and tungsten for localized corrosion resistance with chromium for better performance in oxidizing media. It is widely evaluated for chemical processing, pollution-control equipment, sour gas, pulp and paper, waste treatment and chloride-bearing systems. Its broad resistance makes it useful where feed composition or redox potential may vary.
Broad resistance does not mean universal immunity. Actual performance depends on temperature, concentration, velocity, crevices and contaminants. Published corrosion tables should be treated as screening tools rather than a replacement for project-specific review.
Fabrication and Welding Considerations
Both alloys require clean fabrication practices, compatible filler metal and controlled heat input. Surface contamination by iron, sulfur, lead or low-melting compounds should be avoided. Welding procedures should be qualified for product thickness and service requirements. The finished equipment may require visual examination, liquid penetrant testing, radiography or corrosion testing depending on the specification.
Buyer Selection Checklist
- List every process chemical, concentration and operating temperature.
- Identify oxidizing contaminants and upset conditions.
- State product form, dimensions, standard and heat-treatment condition.
- Specify welding, inspection, PMI and certificate requirements.
- Review crevices, stagnant zones and cleaning chemicals.
- Use corrosion testing or engineering approval for critical service.
Request Alloy Availability
Send the alloy designation, standard, product form, dimensions, quantity, service chemistry, temperature and documentation requirements for a supply review.
Post time: Aug-12-2026