Pay special attention to the temperature rise at the beginning of glass heated glass to avoid excessive thermal stress temporarily. Because of a temporary stress superimposed with the original residual stress can cause breakage of glass in the furnace, commonly known as "blast furnace." Especially when the glass temperature rises to above 350 ° C, the glass will be counter-productive on the change in volume in the furnace, causing the glass to burst. Thick glass at the beginning of the heating if the temperature rise is too fast, will have a huge temporary stress, when there are air bubbles, stones and other materials defect glass core layer, often caused by glass blast furnace.

Generally, the glass used as long as two-thirds of the overall heating time can be at or near the tempering temperature, and then the glass temperature slowly, after a period of time the internal temperature of the glass is mainly used for stress relief and homogenization, this time is necessary, it helps to improve steel quality and yield of the glass.

For all kinds can be tempered Low-E coated glass, the need for forced convection tempering furnace to heat steel. Furnace radiation wavelength of about 3μm, heat radiation Low-E film reflects infrared band, if there is no forced convection system, mainly by the lower surface of the glass absorbs heat both sides of uneven heating glass, glass bending upward, because the bottom of the ceramic roller contact time is too long and overheat, causing optical distortion glass, glass while heating time is greatly extended. Therefore, steel Low-E coated glass should be forced convection tempering furnace heating furnace, so as to ensure product quality tempered glass.