In the present study, a new welding procedure was developed according to the welding difficulties of mechanical clad pipe. The effect of temperature on the corrosion product layer of stainless steel welded joints exposed to a CO2-containing solution was investigated. The measurement techniques, such as scanning electron microscopy with energy dispersive spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy, were used to systematically characterize the morphology and composition of the corrosion product layer. The corrosion rates were calculated by weight loss method. The corrosion mechanisms are studied and discussed. The results showed that temperature is an important factor in the corrosion rate of mechanical clad pipe welded joints.