Nickel Based Alloy: Inconel690 Composition And Application Introduction

Inconel690 has significant antioxidant properties and excellent stress corrosion resistance. It has excellent corrosion resistance to various aqueous media and high-temperature atmospheres. In addition, it also has high strength, good metallurgical stability and excellent processing properties.

Inconel690 chemical composition:
Carbon C: Less than or equal to 0.050
Chromium Cr: 27-37

Iron Fe: 7-11
Manganese Mn: Less than or equal to 0.50
Silicon Si: Less than or equal to 0.50
Phosphorus P: Less than or equal to 0.02
Sulfur S: Less than or equal to 0.015
Copper Cu: Less than or equal to 0.5

Inconel690 physical properties:
Inconel690 density: 8.19g/cm3 Melting point: 1344-1377 degree
Inconel690 elastic modulus: 211 GPa Thermal conductivity: 12.1 λ/(W·m· degree )
Inconel690 hardness: HRB85 Thermal expansion coefficient (20-100 degree ): 14.0 x10-6K-
Main features of Inconel 690: Nickel-based high temperature alloy Inconel 690 It has excellent corrosion resistance and thermal stability.
Inconel 690 alloy exhibits excellent corrosion resistance in various aqueous solutions and gas environments. Due to its high chromium content, it exhibits excellent corrosion resistance in a variety of acidic media such as nitric acid and hydrofluoric acid. In hydrochloric acid, it can resist corrosion at low concentrations (about 15% or less), and has high corrosion resistance to phosphoric acid at room temperature and medium temperature. However, in boiling solutions, it can only withstand low concentrations of acid.

The structure of Inconel690 alloy pipe after solution treatment is austenite + a small amount of carbide + a small amount of Ti(CN). When the solution temperature is between 950~1100 degree , the grain size does not change much. When the solution temperature exceeds 1150 degree , the grain size increases rapidly. Therefore, it is recommended that the solution treatment temperature be below 1100 degree .
After TT treatment, Cr23C6 precipitates along the grain boundaries, and its quantity and size increase with the increase of TT treatment temperature and the extension of holding time, and the distribution morphology changes from single to semi-continuous. After treatment at 800×104 degree or above for 48 hours, the size increases significantly.