Abstract：To study the flakes formation in heavy forging after forging deformation, a flakes formation cohesion zone model of the residual micro-pores after forging deformation was proposed based on the previous experimental study, cohesion zone modeling hydrogen press theory and the theory of hydrogen accumulation under the stress gradient. The effect of material hydrogen concentration, the hydrogen diffusion under hydrogen compression stress field, the cohesive strength of hydrogen and other multi-factors coupling during the flakes formation and extension were studied. The results showed that after forging, the possibility of flakes formation compared with the original micro-pores was greatly reduced. The high concentration of hydrogen was the main factor of flakes initiation, and the high hydrogen's pressure led to the stress concentration at the tip of the pores, and hydrogen's enrichment led to the decrease of fracture strength at the tip of the pores. Compared with micropores, micro-cracks were more likely to induce flakes formation.

Keyword：heavy forging;flakes formation after forging;residual micro-pores after forging;cohesion strength with hydrogen;hydrogen diffusion;