Nickel-based super alloy: Incoloy 926 (UNS N08926/W.Nr.1.4529)

Nickel-based super alloy: Incoloy 926 (UNS N08926/W.Nr.1.4529)

What is Incoloy 926?

The Cr content in nickel-based alloy incoloy 926 is usually 14.0-18.0 %, the nickel content is 24.0-26.0%. Incoloy 926 (N08926) is a nickel-based alloy 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. It is more resistant to high temperature than traditional chromium-nickel stainless steel 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 the higher grades whose service temperature is as high as 1900°F (1038°C) alloy.

Chemical composition (%) of nickel-based alloy incoloy 926 (UNS N08926):

C≤	Si≤	Mn≤	P≤	S≤	Cr≥	Ni≥	Mo≥	Cu≤
0.04	0.75	1.50	0.030	0.015	14.0-18.0	26.0-30.0	2.50-3.50	3.50-5.50
other	N≤	Al≤	Ti≤	Fe≤	Co≤	V≤	W≤	Nb≤
	0.15-0.25	0.30	1.50-2.30	margin	–	–	–	–

Mechanical Properties of nickel-based alloy incoloy 926 (UNS N08926/W.Nr.1.4529):

Alloy state	Tensile strength Rm N/mm2	Yield strength RP0.2N/mm2	Elongation A5 %
926	650	295	35

Physical properties of nickel-based alloy incoloy 926 (UNS N08926/W.Nr.1.4529):

Density	8.1 g/cm3
Melting point	1320-1390 ℃

Corrosion Properties of nickel-based alloy incoloy 926 (UNS N08926/W.Nr.1.4529):

Corrosion condition	Temperature	Corrosion rate			Corrosion condition	Temperature	Corrosion rate
		Myp	mm/a				Myp	mm/a
0.2%HCI	Boiling	<0.10	<0.00		60.0%H2SO4	70	9.4	0.24
1.0%HCI	90	37	0.94			30	6	0.15
	70	0.02	<0.00		95.0%H2SO4	50	18.9	0.48
5.0%HCI	50	43.4	1.1			30	12.5	0.32
	30	10.6	0.27		85.0%H3PO4	90	0.24	0.01
10.0%H2SO4	Boiling	10.4	0.26		80.0%HC2H3O2	Boiling	<0.10	<0.00
	70	2.5	0.06

Corrosion resistance of incoloy 926 (UNS N08926/W.Nr.1.4529):

926 is an austenitic stainless steel alloy has a similar chemical composition with 904L alloy, its nitrogen content is 0.2%, molybdenum content is 6.5%. Molybdenum and nitrogen content significantly increased the resistance of pitting and crevice corrosion  in the halide media.Meantime, nickel and nitrogen not only ensures the stability of metallographical, but also reduce separating intergranular trend in the thermal process or welding process better than the nitrogen content of nickel alloy. 926 has particular corrosion resistance in the chloride ions medium due to the excellent local corrosion resistance and 25% nickel alloy content.A variety of experiments in the 10000-70000ppm of Chloride concentration, PH 5-6, 50-68℃ operating temperature of the slurry of limestone FGD system show that, after a 1-2 year trial period, 926 alloy without pitting and crevice corrosion.926 in other chemical media also has good corrosion resistance in the high temperature and high concentration of media, including sulfuric acid, phosphoric acid, acid gas, sea water, salt and organic acids.926 is the material that choosed for BAM directory Chapter 6 of “dangerous goods storage and transportation containers norms”  by  Berlin, Germany’s national Institute for Materials Research and Testing (BAM) . In addition, in order to have the best corrosion resistance only when the material is in the right state of metallurgy and guarantee clean conditions.

Characteristic of nickel-based alloy incoloy 926 (UNS N08926/W.Nr.1.4529):

• 1.It has high resistance to pitting and crevice corrosion when in Halide and H2S contained acid media.
• 2.In practice, effective in resistance of chloride stress corrosion cracking.
• 3.A variety of corrosion have good corrosion resistance capability in the normal oxidation and restore environment.
• 4.Upgrade mechanical properties than Cronifer 1925 LC-Alloy 904 L.
• 5. Alloys has Improved the stability of metallurgical compared to a range of 18% of the nickel content alloys.
• 6.With a certification of applied in manufacturing-related  pressure vessel （VdTUV-196～400℃ and ASME ）

Processing and heat treatment of incoloy 926 (UNS N08926/W.Nr.1.4529):

Incoloy926 nickel-based alloy is suitable for cold and hot processing and machining, but due to its high strength, cold and hot processing requires high-power processing equipment.   

Heating of Incoloy 926 (UNS N08926/W.Nr.1.4529): 

• (1) Keep the workpiece clean before and during heat treatment.
• (2) Do not touch sulfur, phosphorus, lead and other low melting point metals during the heat treatment process, otherwise it will damage the performance of the material. Care should be taken to remove dirt such as marking paint, temperature indicating paint, colored crayons, lubricating oil, fuel, etc.
• (3) The lower the sulfur content in the fuel, the better. The sulfur content in natural gas should be less than 0.1%, and the sulfur content in heavy oil should be less than 0.5%.
• (4) Considering the need for temperature control and keeping clean, it is best to conduct heat treatment in a vacuum furnace or a gas shielded furnace.
• (5) It can also be heated in a box furnace or a gas furnace, but the furnace gas must be clean and neutral to slightly oxidizing. The furnace gas should be avoided from fluctuating between oxidizing and reducing properties. The heating flame cannot be directly heated. Burn to the workpiece.

Thermal processing of incoloy 926 (UNS N08926/W.Nr.1.4529):  

• (1) The thermal processing temperature of Incoloy 926 (N08926) alloy ranges from 1200°C to 900°C, and the cooling method is water quenching or rapid air cooling.
• (2) When heating, the material can be directly fed into the furnace that has been heated to the highest working temperature. After holding for sufficient time (60 minutes of holding time per 100mm thickness) is quickly released, and the heating is carried out in the high temperature section of the specified temperature range. Processing. When the material temperature drops below the thermal processing temperature, it needs to be reheated.  
• (3) In order to get the best performance, solution treatment should be carried out after thermal processing.   

Cold working of incoloy 926 (UNS N08926/W.Nr.1.4529):  

• (1) Like all austenitic chromium-nickel stainless steels, Incoloy 926 (N08926) alloy has a large work hardening rate, so it is necessary to select processing equipment. The cold-worked material should be in a solution heat-treated state, and intermediate annealing should be carried out when the amount of cold work is large.  
• (2) If the amount of cold working is greater than 15%, the workpiece needs to be treated with a second solution.    

Heat treatment of incoloy 926 (UNS N08926/W.Nr.1.4529):  

• (1) The solution treatment temperature range of Incoloy 926 (N08926) alloy is 1150℃～1200℃, and the most suitable temperature is 1170℃.  
• (2) The cooling method for materials with thickness greater than 1.5mm is water quenching, and materials with thickness less than 1.5mm can also be cooled by rapid air cooling. If air cooling is used.  
• (3) During the heat treatment process, the material can be directly fed into the furnace with the highest working temperature, and the workpiece must be kept clean.   

Deoxidation and pickling of incoloy 926 (UNS N08926/W.Nr.1.4529):

• (1) Incoloy 926 (N08926) alloy has stronger adhesion of surface oxides and weld slag around the weld than low alloy stainless steel. It is recommended to use Fine-grained abrasive belt or fine-grained grinding wheel for grinding.  
• (2) Before pickling with HNO3/HF mixed acid for appropriate time and temperature, it must be carefully polished or salt bath pretreatment to break the oxide film.   

Machining of incoloy 926 (UNS N08926/W.Nr.1.4529):

Incoloy 926 (N08926) alloy should be machined after heat treatment. Due to the work hardening of the material, it is advisable to use a lower cutting speed and re-entry than processing low alloy standard austenitic stainless steel Only when the knife is processed can it be turned under the hardened surface.

Application areas of nickel-based alloy incoloy 926 (UNS N08926/W.Nr.1.4529):

Incoloy 926 (N08926) alloy is a multi-purpose material, which can be used in many industrial fields:

• Fire system, water purification system, marine engineering and hydraulic piping perfusion system.
• The pipeline, joint, air systems in the acidic gas production.
• Evaporator, the heat exchanger, filter, mixer, etc. in the phosphate production.
• Power plants condensation and pipe system in the use of sewage water to cool water.
• The use of acidic organic catalyst chlorinated derivatives production.
• The production of cellulose pulp,Polished bar in the orrosive oil wells.
• Hose system in the oceanngineering,Flue gas desulphurization system components.
• Sulfuric acid condensation and separation system,Crystalline salt concentration and the evaporator.
• Transport of corrosive chemicals containers,Reverse osmosis desalination plan.
• Heat exchange tubes
• Pipe fittings
• Flanges
• Valves

Variety specifications and supply status of Nickel-based super alloy: Incoloy 926 (UNS N08926/W.Nr.1.4529):

Variety classification:

Yaang Pipe Industry can produce various specifications of Incoloy 926 seamless pipe, Incoloy 926 steel plate, Incoloy 926 round bar, Incoloy 926 forgings, Incoloy 926 flange, Incoloy 926 pipe fittings, Incoloy 926 welded pipe , Incoloy 926 steel strip, Incoloy 926 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.

Source: China Incoloy 926 Flanges Manufcturer – Yaang Pipe Industry (www.steeljrv.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

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