Publication details
Weld joint simulations of heat-resistant steels
| Authors | |
|---|---|
| Year of publication | 2004 |
| Type | Article in Periodical |
| Magazine / Source | Archives of Metallurgy and Materials |
| MU Faculty or unit | |
| Citation | |
| Field | Physical chemistry and theoretical chemistry |
| Keywords | phase profile carbon redistribution electrode weld DICTRA |
| Description | Knowledge of microstructure stability is essential for reliable estimations of the lifetime limitations of materials and welded joints at higher temperatures. The CALPHAD method complemented with appropriate diffusion approach can help us to simulate phase and element profile evolutions inside diffusion-affected zone of weld joint. The different heat-resistant steels (alloying base: Cr, Ni, Mo, V, C, N) and their weld joints are objects of our study. The particular results of the equilibrium calculations are presented as phase diagram cross-sections and element activities of the selected heat-resistant steels. The carbon and nitrogen activity temperature dependences were calculated for individual steels. The difference in these activities in two different steels (at given temperature) indicates diffusion flow direction, which can be opposite then deduced from the element content (up-hill diffusion). The simulations respect the coexistence of different carbide phases in the materials and they are conducted on the assumption that local phase equilibrium holds and that diffusion is the control process of phase transformation. The phase diagram calculations and diffusion couple simulations involving time-distance dependences for phase and element redistributions in diffusion-affected zones enabled us to obtain basic information, which allow estimating thermodynamic and diffusion stabilities of the studied heat-resistant steels and their weld joints. |