INTERNALLY TINNED COPPER PIPE FOR FEEDING WATER AND HOT WATER AND PRODUCTION THEREOF

摘要

PURPOSE:To obtain a low-cost internally tinned Cu pipe suppressing the leaching of Cu ions in tap water and easy to handle by coating the inside of a Cu pipe with an Sn layer by substitution tinning or chemical reduction tinning. CONSTITUTION:When the inside of a Cu pipe is coated with an Sn layer consisting of Sn grains by substitution tinning or chemical reduction tinning to produce an internally tinned Cu pipe for feeding water and hot water, a pretreating soln. for tinning and 1-20g/l (expressed in terms of Sn) tinning soln. for substitution tinning or chemical reduction tinning are continuously circulated in the coil-shaped Cu pipe from an open end for 10-60min to form an Sn layer of =3mum thickness on the inside of the Cu pipe. An internally tinned Cu pipe preventing the leaching of Cu ions can be produced.