Accurate simulation and measurement of the residual stress are pressing needs in ultrathin glass (UTG) industrial stable production. Herein, the heat transfer in an annealing lehr and the residual stresses at different positions along the width of the UTG ribbon were simulated by the finite element method and measured via the Vickers indentation. The residual stresses at 400 and 600 mm to the edge were large, which caused serious production loss. Besides, we conducted molecular dynamics (MD) simulation to reveal the mechanism for residual stress formation. During UTG cooling, the cooling rate of the core is slower than that of the surface. Due to the influence of the relaxation process, the latter would hinder the former's R–O (where R is Na, Mg, Ca, Al, or Si) length contraction, implying that the surface would generate residual compressive stress. The temperature difference between them increases as the cooling rate grows, leading to the residual stress increase. Finally, based on revealing the formation principle of residual stress by MD, the edge electric heatings were set in zone B, and the residual stresses at 400 and 600 mm to the edge are reduced.

A kind of float glass spot defect, characterized by small size, metallic luster, and difficult to clean, adheres only to the lower surface (contacts with molten tin) of the float glass ribbon. This defect causes serious production loss. Therefore, determining the precise source of this spot defect and the effective prevention of its occurrence is vital in the scientific interest and technological significance. Herein, we report a new idea for preventing glass spot defect resulting from roller hydrogen embrittlement (HE) via regulating protective atmosphere distribution. We also reveal its formation mechanism. The generation mechanism of this spot defect shows that the protective atmosphere in the tin bath diffuses into the annealing lehr. However, the annealing lehr does not effectively discharge it (particularly H2). Thus, roller HE occurs. Opening the vent decreases the H2 concentration around the roller. In addition, the vent is moved by ∼1 m in the original position toward the exit of the annealing lehr, which is most conducive to H2 discharge. This optimization measure reduces or eliminates the spot defect caused by the HE of the roller. Moreover, it has great application potential in the design of float glass annealing lehr.

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