Incoloy825 Product Introduction

 　　1、 Overview

　　Incoloy825 is a fully austenitic nickel iron chromium alloy stabilized with titanium, with the addition of copper and molybdenum.

　　Incoloy825 has the following characteristics:

　　Good stress corrosion cracking resistance.

　　Good resistance to spot corrosion and crevice corrosion

　　Good antioxidant and non oxidative thermal acid properties

　　Good mechanical properties at room temperature and high temperatures up to 550 ℃

　　Certification for pressure vessels with manufacturing temperatures up to 450 ℃

　　Physical and Chemical Properties of Incoloy825

　　Incoloy825 Density: ρ= 8.14g/cm3

　　Incoloy825 melting temperature range: 1370~1400 ℃

　　Physical properties of Incoloy825 alloy:

　　Mechanical properties of Incoloy825

　　The properties listed in the following table are applicable to the specified specifications of Incoloy825 alloy products after softening annealing (stabilization annealing). The special properties of non-standard size materials can be provided according to the requirements of specific applications.

　　Incoloy825ISO V-notch impact test:

　　Average room temperature value: axial>=150J/cm2

　　Radial>=100J/cm2

　　Time temperature sensitization curve

　　Incoloy825 Organizational Structure

　　Incoloy825 conditional stress value:

　　A high conditional stress value of 90% yield strength can be applied in applications where slightly larger deformation is allowed. The permanent stress caused by these stresses can cause dimensional changes, therefore it is not recommended for flange and sealing gasket connections.

　　Incoloy825 metallographic structure:

　　Incoloy825 alloy has a stable face centered cubic structure. The chemical composition and appropriate heat treatment ensure that corrosion resistance is not weakened by sensitization.

　　Incoloy825 corrosion resistance:

　　Incoloy825 is a versatile engineering alloy that exhibits resistance to acid and alkali metal corrosion in both oxidizing and reducing environments.

　　The high nickel content makes the alloy have effective resistance to stress corrosion cracking.

　　Good corrosion resistance in various media, such as sulfuric acid, phosphoric acid, nitric acid, and organic acids, as well as alkali metals such as sodium hydroxide, potassium hydroxide, and hydrochloric acid solutions.

　　The high comprehensive performance of Incoloy825 is demonstrated in the nuclear combustion dissolver with diverse corrosive media, such as sulfuric acid, nitric acid, and sodium hydroxide, all treated in the same equipment.

　　Incoloy825 Process Performance and Requirements

　　Incoloy825 processing and heat treatment

　　Incoloy825 alloy is easy to process in general industrial processes.

　　Incoloy825 preheating:

　　Temperature control is crucial for ensuring that the corrosion resistance of alloys is not weakened by sensitization. The workpiece must undergo surface cleaning before and during heating to maintain surface cleanliness.

　　If the heating environment contains sulfur, phosphorus, lead, or other low melting point metals, the Nicrofer 6023/6023H alloy will become brittle. Impurities come from marked paint, chalk, lubricating oil, water, fuel, etc. The sulfur content of fuel should be low, such as the impurity content of liquefied gas and natural gas should be less than 0.1%, the sulfur content of urban gas should be less than 0.25g/m3, and the sulfur content of petroleum gas should be less than 0.5%, which is ideal.

　　It is best to perform heat treatment in a vacuum resistance furnace or inert gas protective atmosphere, as this can accurately control temperature and prevent contamination by impurities. If the impurity content of gas is low, a gas heating furnace can also be considered to obtain a neutral or weakly oxidizing atmosphere. The fluctuation of furnace gas composition in oxidizing and reducing properties should be avoided, and the combustion flame cannot directly burn towards the workpiece.

　　Incoloy825 hot working:

　　The suitable hot working temperature of Incoloy825 alloy is 1150-900 ℃, and the cooling mode can be water quenching or rapid air cooling.

　　During hot working, the workpiece can be directly sent to the furnace that has reached the temperature. After the furnace reaches temperature, the insulation time of the material is 60 minutes per 100mm thickness. After the insulation reaches the specified time, it should be immediately discharged from the furnace and processed within the specified temperature range. If the temperature of the metal drops below the minimum processing temperature, it should be reheated.

　　After hot working, annealing shall be carried out in time to ensure the best corrosion resistance and suitable crystal structure.

　　Incoloy825 cold working:

　　Cold working shall be carried out after solution treatment. The work hardening rate of Incoloy825 is close to that of austenitic stainless steel, so the processing equipment shall be adjusted accordingly.

　　When there is a large amount of cold working, there should be an intermediate annealing process. When the final cold deformation exceeds 15%, final stabilization treatment is required.

　　Incoloy825 Heat Treatment:

　　The temperature range for softening annealing or stabilization treatment is 920-980 ℃,

　　The most suitable temperature is 940 ± 10 ℃.

　　For workpieces with a thickness greater than 1.5mm, it is recommended to use water quenching or rapid air cooling to achieve maximum creep resistance.

　　During any heat treatment process, attention should be paid to the previously mentioned matters related to maintaining cleanliness.