Materials Performance

MAY 2017

Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.

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Page 13 of 76

11 NACE INTERNATIONAL: VOL. 56, NO. 5 MATERIALS PERFORMANCE MAY 2017 THE BLOG Continued on page 13 Correction In the April 2017 MP Corrosion Basics article, "Materials in High Temperatures," there was an incorrect conversion in the chart from degrees Celsius to degrees Fahrenheit. The melting temperature of copper is 1,083 °C (1,984 °F). MP thanks NACE International member Larry Muller, director of Metallurg y and Tech- nical Services at Chase Brass and Copper Co. (Montpelier, Ohio), for catching the error and bringing it to our attention. The following are excerpts f rom the NACE International Corrosion Net work (NCN) and NACE Coatings Net work . These are email-based discussion g roups for corrosion professionals , with more than 3 ,000 participants . The excerpts are selected for their potential interest to a large number of NACE members . They are edited for clarit y and leng th . Authors are kept anony mous for publication . Please be advised that the items are not peer-reviewed , and opinions and sug gestions are entirely those of the inquirers and respondents . NACE does not g uarantee the accuracy of the techni- cal solutions discussed . M P welcomes additional responses to these items . They may be edited for clarit y. For information on how to subscribe to these f ree list ser vers , click on the "Corrosion Central " link and then "Online Corrosion Communit y List Ser vers" on the NACE web site: nace .org. Preventing Corrosion of Welded Areas on Carbon Steel Pipes Q: Carbon steel water pipes often have an internal cement lining. The cement lining ends several inches before the pipe ends for welding. What are the best options to protect these areas? Is there any ty pe of coating system that can be applied before f inal welding, ty pically for smaller-size pipe (e.g., 6-in [152-mm] diameter)? For larger-diameter pipe, the joints can be patched manually after welding is done. Has anyone tried using a localized anode for the joints? A: Most cement mortar-lined pipes are spigot and socket connec- tions so there is no welding. Some large- diameter lines with cement linings are welded and the internal field joint is cleaned and mortar lined afterward. Have you considered lining with an epoxy and then using robotics to line the field joints afterward? A: ere is also a good deal of mortar-lined pipe that is welded together. If the welding process is done correctly, you can achieve five to 20 years of service life. If the welds are not done correctly, the service life can be much shorter. e cost of mortar-lined pipe is not much more than bare steel pipe. How- ever, this assumes the factory effectively installs the mortar, the transporter ships it without damaging it, the off-loader does not damage it while unloading, and the welder installs it correctly. is adds

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