Ramberg-Osgood Stress-Strain Analysis of the Effects of Aging Treatment and Welding on IN600 with a Three-Stage Strain Hardening Behavior

The Ramberg-Osgood equation was applied to model the stress-strain behavior of heat-treated and welded specimens of Inconel 600 up to 0.2 and 0.175 mm/mm of strain, respectively. As-received and aged plates of Inconel 600 were gas metal arc welded to simulate repair of a component in operation. Dog bone shape specimens were tensile tested at a cross head speed of 0.005 s(-1) and the deformation was measured with an extensometer with a gage length of 20 mm. Microstructural observations were made in the optical and scanning electron microscope. Fitting the experimental data in the plastic region of stress-strain curves to a novel three slopes Ramberg-Osgood model enabled estimation of the hardening coefficient, n. The value of n varied from 0.07 to 0.3 depending on the metallurgical condition of the specimen. A notorious increase was observed in the value of n for samples heat-treated beyond 25 h and in as-welded samples. The results of this work showed a very good correlation between the model and the experimental curves. Graphic Abstract

Automated summary

The Ramberg-Osgood equation was used to model the stress-strain behavior of Inconel 600 specimens, showing a correlation between the hardening coefficient n and the metallurgical condition of the specimen, with a notable increase in n for samples heat-treated beyond 25 hours.