Abstract: 12 Processes with various controlled-rolling, controlled-cooling and coiling temperatures have been designed. The behavior of Nb (C,N) precipitation, dislocation density, sub grain state, texture, ferrite grain size and pealite fraction have been examined experimentally. Each strengthening effect has been calculated and the interaction between them have been analysised, as a result of which it can be concluded that fine grain strengthening is the most important strengthening mechanism and subgrain strengthening, texture strengthening and pealite strengthening can be neglected under the condition finished in austenite range, and there are heavy interactions between precipitation and dislocation strengthening. A new yield strength evaluation formula for controlling rolled micrealloyed steels finished in austenite range has been built.

Key words: 估算, 屈服强度, 微合金钢, Cantilever beam, Multiple outputs, Nonlinear systems, REFOR algorithm, Dynamic parametrical model