A Comprehensive Guide to Nickel-based super alloy: Incoloy 840 (Alloy 840/W.Nr. 1.4847)

What is Incoloy 840?

Nickel-based super alloy Incoloy 840 (Alloy 840/W.Nr. 1.4847): The Cr content in Incoloy 840 nickel-based alloy is usually 18-20%, and the nickel content is 19-21%. Incoloy 840 alloy is a kind of austenitic stainless steel containing titanium and aluminum. It contains enough chromium to form and maintain a sufficient scale of chromium oxide to protect it under high temperature conditions and is more resistant to high temperatures than traditional chromium-nickel stainless steels such as 304; The higher nickel content makes it have better oxidation resistance than the standard 18-8 stainless steel, and its oxidation resistance is not inferior to higher-grade alloys whose service temperature is as high as 1900°F (1038°C) . Therefore, Incoloy 840 alloy is an ideal material for manufacturing electric heating pipes, automobile emission control systems and other high temperature resistant products.

Characteristics of Incoloy 840

• 1). Corrosion resistance: Incoloy alloy 840 alloy has excellent corrosion resistance in strong acids, strong alkalis, high temperatures, high pressure, and other harsh environments that can still maintain stable performance.
• 2). High temperature strength: Incoloy alloy 840 alloy has excellent strength and durability and can withstand high temperatures and high pressure environments.
• 3). Oxidation resistance: Incoloy alloy 840 alloy has excellent oxidation resistance, can maintain stable performance at high temperatures for a long time and is not easy to oxidize.
• 4). Creep resistance: Incoloy alloy 840 alloy has good creep resistance in high temperature and high pressure environments and can withstand long-term use.
• 5). Fatigue resistance: Incoloy alloy 840 alloy has good fatigue resistance and can withstand long-term use.
• 6). Mechanical strength: Incoloy 840 alloy is very strong in the high temperature environment in the thermal expansion and contraction of the mechanical strength remain unchanged, so it has high fatigue strength.
• 7). Good processing performance: Incoloy 840 alloy is easy to process and can be used in various processing methods, including extrusion, rolling, drawing, and cold heading.

Unlike Incoloy 800, Incoloy 840 is an austenitic alloy containing chromium, nickel, and molybdenum. This alloy is resistant to reducing and oxidizing acids, stress corrosion, cracking, and pitting corrosion. This makes it an ideal choice for petrochemical applications such as pump shafts or turbine blades, which must withstand harsh chemicals for a long time without corrosion or degradation. However, unlike the Incoloy 800, it cannot age harden, so its strength stays the same over time. In addition, it can only be used at temperatures up to 1000 ℉ (538 ℃).
Incoloy 800 alloy is an austenitic stainless steel containing titanium aluminum alloy that provides higher temperature calibration resistance than traditional chromium-nickel stainless steel (such as type 304). Compared to high alloy grades up to 1900 ° F (1038 ° C), the oxidation resistance of Incoloy 800 alloy is advantageous, making it an important application for heating elements, automotive emission control systems, and high-temperature degradation resistance.
Incoloy840 alloy is a universal material for electric heating components. It is suitable for a combination of formability, weldability, corrosion resistance, and oxidation resistance. The alloy composition leads to the formation of the commonly required oxide layer during natural gas combustion. Due to the chromium and nickel content selected for the alloy, this oxide layer is very common in use. This alloy has excellent environmental resistance and is also suitable for processing. For example, Incoloy840 alloy should ensure effective chromium and nickel to adapt to the corrosive environment present in the active exhaust system.

Chemical composition % of Incoloy 840 (Alloy 840/W.Nr. 1.4847)

C≤	Si≤	Mn≤	P≤	S≤	Cr≥	Ni≥	Mo≥	Cu≤
0.08	1.00	1.00	0.040	0.030	18.0-20.0	19.0-21.0	–	–
Other	N≤	Al≤	Ti≤	Fe≤	Co≤	V≤	W≤	Nb≤
	–	–	0.15-0.60	Margin	–	–	–	–

Physical properties of Incoloy 840 (Alloy 840/W.Nr. 1.4847)

• Incoloy 840 nickel-based alloy elastic modulus: 29×106 PSI (200 GPA)
• Incoloy 840 nickel-based alloy density: 0.29 lb/in³ (8.03 g/cm³)

Incoloy Thermal conductivity of 840 nickel-based alloy

°F	°C	Btu·in/h·ft2·°F	W/m·K
68-132	20-56	90.0	12.9
68-204	20-96	93.6	13.5
68-333	20-167	104.4	15.0
68-465	20-241	114.0	16.3
68-590	20-310	122.4	17.6
68-726	20-385	133.2	19.2
68-848	20-453	145.2	20.9
68-972	20-522	156.0	22.4
68-1101	20-594	168.0	24.1
68-1198	20-648	181.2	26.0

Advantages and disadvantages of Incoloy 840

Incoloy 840 is a high-temperature alloy composed of nickel, chromium, iron, copper, molybdenum, and zirconium. Its main advantages are high resistance to corrosion, high temperatures and pressures, good machinability, and suitability for use in high-temperature, highly corrosive environments. However, it also has some disadvantages; here is a comparison of the advantages and disadvantages of the Incoloy 840 alloy.
Advantages:

• 1). High-temperature stability: Incoloy 840 alloy has high stability in high-temperature environments and can be operated for long periods below 700°C without easy annealing and sintering, so it is very suitable for use in high-temperature environments.
• 2). Excellent corrosion resistance: Incoloy 840 alloy has excellent corrosion resistance, can resist various corrosive media, and does not easily adsorb harmful elements, especially for sulfate, chloride, nitrate, and other media have good corrosion resistance.
• 3). Mechanical strength: Incoloy 840 alloy is very strong in high temperature environments; the mechanical strength remains unchanged under thermal expansion and contraction and has high fatigue strength.
• 4). Good machinability: Incoloy 840 alloy is easy to machine and can be used in various processing methods, including extrusion, rolling, drawing, and cold heading.

Disadvantages:

• 1). Expensive: Incoloy 840 alloy is expensive, which may not be the most economical choice in some cases.
• 2). Somewhat toxic: During processing and machining, Incoloy 840 alloy may produce some toxic gases and pollutants that can harm operators and the environment.

Incoloy 840 alloy has excellent performance in high temperatures and strong corrosive environments, with high corrosion resistance and mechanical strength. However, it is necessary to consider the defects of being expensive and having some toxicity, so its use must be carefully evaluated.

Application areas of nickel-based alloy incoloy 840 (W.Nr. 1.4847)

Incoloy alloy 840 alloy is widely used in petroleum, chemical, electric power, electronics, and other fields. Among them, it is mainly used in the following fields:

• 1). Chemical reactor: Incoloy 840 alloy has excellent corrosion resistance and high-temperature strength in chemical reactors and can withstand harsh environments such as strong acids and alkalis.
• 2). Oil mining equipment: Incoloy 840 alloy has excellent corrosion resistance and high-temperature strength in oil mining equipment, able to withstand high temperature and high pressure environments.
• 3). Nuclear power plant steam generator: Incoloy 840 alloys in the nuclear power plant steam generator has excellent oxidation resistance and high temperature strength, and can withstand high temperature and high pressure environments.
• 4). Oil refining equipment: Incoloy 840 alloy has excellent corrosion resistance and high temperature strength in oil refining equipment, able to withstand strong acid, alkali, and other harsh environments.

Variety specifications and supply status of Nickel-based super alloy: Incoloy 840 (Alloy 840/W.Nr. 1.4847)

Variety classification

Yaang Pipe Industry can produce various specifications of Incoloy840 seamless pipe, Incoloy840 steel plate, Incoloy840 round bar, Incoloy840 forgings, Incoloy840 flange, Incoloy840 pipe fittings, Incoloy840 welded pipe , Incoloy840 steel strip, Incoloy840 wire and supporting welding materials. 

Delivery status

• Seamless pipe: solid solution + acid white, length can be set;
• Plate: solid solution, pickling, trimming;
• Welded pipe: solid solution acid white + RT% flaw detection;
• Forging: annealing + car polish; Bars are forged and rolled, surface polished or car polished;
• Strips are delivered after cold rolling, solid solution soft state, and deoxidized;
• Wire rods are finely ground in solid solution pickled disk or straight strips, solid solution straight strips Delivery in light state.