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What are the characteristics of Hastelloy C276?

Views: 6     Author: Wang     Publish Time: 2024-07-18      Origin: Site

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Description of Hastelloy C276 / UNS N10276 / W.Nr. 2.4819

Hastelloy C276 is a Nickel-chromium-molybdenum wrought alloy that is considered the most versatile corrosion resistant alloy available. This alloy is resistant to the formation of grain boundary precipitates in the weld heat-affected zone, thus making it suitable for most chemical process applications in an as welded condition. Alloy C276 also has excellent resistance to pitting, stress-corrosion cracking and oxidizing atmospheres up to 1900°F. Alloy C276 has exceptional resistance to a wide variety of chemical environments.


Hastelloy C276 is a nickel-molybdenum-chromium superalloy with an addition of tungsten designed to have excellent corrosion resistance in a wide range of severe environments. The high nickel and molybdenum contents make the nickel steel alloy especially resistant to pitting and crevice corrosion in reducing environments while chromium conveys resistance to oxidizing media. The low carbon content minimizes carbide precipitation during welding to maintain corrosion resistance in as-welded structures. This nickel alloy is resistant to the formation of grain boundary precipitates in the weld heat-affected zone, thus making it suitable for most chemical process application in an as welded condition.


HASTELLOY C276 alloy (UNS N10276) was the first wrought, nickel-chromium-molybdenum material to alleviate concerns over welding (by virtue of extremely low carbon and silicon contents). As such, it was widely accepted in the chemical process and associated industries, and now has a more than 50-year-old track record of proven performance in a vast number of corrosive chemicals. Like other nickel alloys, it is ductile, easy to form and weld, and possesses exceptional resistance to stress corrosion cracking in chloride-bearing solutions (a form of degradation to which the austenitic stainless steels are prone). With its high chromium and molybdenum contents, it is able to withstand both oxidizing and non-oxidizing acids, and exhibits outstanding resistance to pitting and crevice attack in the presence of chlorides and other halides. Furthermore, it is very resistant to sulfide stress cracking and stress corrosion cracking in sour, oilfield environments.


Alloy C-276 Chemical Composition (%)


(Ni) Nickel

Remainder

(Mo) Molybdenum

15.0 to 17.0

(Cr) Chromium

14.5 to 16.5

(Fe) Iron

4.0 to 7.0

(W) Tungsten

3.0 to 4.5

(Co) Cobalt

2.5 max

(Mn) Manganese

1.0 max

(V) Vanadium

0.35 max

(Si) Silicon

0.08 max

(P) Phosphorus

0.04 max

(S) Sulfur

0.03 max

(C) Carbon

0.010 max


Properties of Hastelloy C276 Alloy

Resistance to Corrosion

Hastelloy C276 is one of the most universally corrosion resistant alloys available today. It is used in a variety of environments ranging from moderately oxidizing to strong reducing conditions. Alloy C276 has exceptional resistance to sulfuric acid, hydrochloric acid, formic acid, acetic acid, chlorides, solvents, wet chloride gas, hypochlorite and chlorine solutions. Hastelloy C276 has excellent resistance to phosphoric acid at all temperatures below boiling and concentrations lower than 65%. The limiting factor when dealing with strong oxidizing environments is the low chromium content, which means hot concentrated nitric acid environments are not desirable.


Hastelloy C276 has superior resistance to pitting, stress corrosion cracking and oxidizing atmospheres. Alloy C276 also exhibits resistance to corrosion by seawater in crevice conditions, which can induce aggressive attack in other commonly used materials.


Fabrication and Heat Treatment

Alloy C276 can be formed using various cold and hot working processes. Like other nickel alloys, alloy C276 work hardens quickly, though it can be cold formed using aggressive methods like deep drawing, press forming and punching. Hot forming should be performed within a temperature range between 1600°F and 2250°F (870°C and 1230°C) with heavier sections being heated to a minimum temperature of 2000°F before forming. Annealing of the material after working is advised and should be performed at a temperature between 2050°F and 2150°F, followed by a rapid quench in a protective atmosphere or agitated reducing quench bath. To obtain a reducing quench bath, add 2% (by volume) of either ethyl or propyl alcohol to water.


Workability

Hastelloy C276 can be forged, hot-upset, and impact extruded. Although the alloy tends to work-harden, it can be successfully deep-drawn, spun, press formed or punched. All of the common methods of welding can be used to weld alloy C276, although the oxy-acetylene and submerged arc processes are not recommended when the fabricated item is intended for use in corrosion service. Special precautions should be taken to avoid excessive heat in-put.


Welding

Gas tungsten-arc welding, gas metal-arc welding, shielded metal-arc (coated electrode) welding, or resistance welding may be used. Minimum heat input consistent with adequate penetration reduces the chance of hot-cracking. Oxyacetylene welding should be avoided due to possibility of carburization. Hastelloy C276 can be used in the as-welded condition in most chemical and petrochemical process equipment.


hastelloy c276

Applications of hastelloy c276

Chemical Processing Industry

The chemical processing industry extensively utilizes Hastelloy C276 due to their outstanding corrosion resistance against various corrosive chemicals. These tubes are often used in applications involving strong acids, such as sulfuric acid, hydrochloric acid, and phosphoric acid. Hastelloy C276 tubes can withstand the highly corrosive nature of these acids, making them suitable for components in chemical reactors, distillation columns, heat exchangers, and scrubbers.


Oil and Gas Industry

Hastelloy C276 have significant applications in the oil and gas industry, particularly in harsh environments and corrosive fluids. These tubes are commonly used in offshore platforms, oil refineries, and petrochemical plants. Hastelloy C276 exhibits exceptional resistance to chloride-induced stress corrosion cracking (SCC) and pitting, making it well-suited for applications in chloride-rich environments, such as seawater, brine, and sour gas.


Power Generation

Hastelloy C276 play a vital role in the power generation industry, where resistance to high temperatures and aggressive environments is crucial. These tubes are commonly used in boilers, heat exchangers, and condensers. Hastelloy C276’s resistance to oxidation and carburization at elevated temperatures allows it to withstand the demanding conditions encountered in power plants, including high-pressure steam and corrosive flue gases.


Pharmaceutical Industry

In the pharmaceutical industry, where stringent cleanliness and product purity are essential, Hastelloy C276 are favored for their excellent resistance to corrosion and contamination. These tubes are used in critical applications such as pharmaceutical reactors, storage tanks, and pipework systems. Hastelloy C276’s resistance to a wide range of chemicals and sanitizing agents makes it suitable for maintaining high cleanliness and product integrity standards in pharmaceutical manufacturing processes.


Waste Treatment and Pollution Control

Hastelloy C276 play a significant role in waste treatment and pollution control systems. These tubes are commonly used in flue gas desulfurization (FGD) systems, providing reliable corrosion resistance against the highly acidic gases produced by industrial combustion. Hastelloy C276 also find applications in wastewater treatment plants, chemical scrubbers, and incineration facilities, helping to mitigate environmental pollution and maintain operational efficiency.

JN Alloy is a distributor and product manufacturer of stainless steel, duplex steel, and nickel.
Tel: +86 19339900211
Add: Stainless steel Market 289, Xinwu District , Wuxi, China
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