Seamless Tubes for Air Pre-heaters Were Delivered in batches



In the middle of July, KANGHONG received a purchasing demand from an air pre-heater manufacturer, who was in urgent need of a batch of seamless tubes for American standard A423 Gr.3 air pre-heater with product specifications of 40*1.5 and 50*2. The manufacturer used welded steel tubes as the tube tank before, while the service cycle of the equipment was shorter than expected. This time, they decided to use seamless steel tube instead of the original welded steel tube, and put forward high corrosion resistance and wear resistance requirements for seamless steel tube. If the steel tube used in the air pre-heater is damaged, cracked, leaked or blocked in the process of use, it will affect the overall operation efficiency of the equipment; The reasons for the above phenomena are the erosion and wear of fly ash in flue gas, dew point acid corrosion formed after the temperature reaches the acid dew point, ammonia escape after the combination of SCR and SNCR, and ammonium bisulfate scale is formed to block the pipeline. In view of the above situation and combined with the standard requirements, KANGHONG decided to reasonably adjust the contents of Ni, Cu, Mo and other elements in the tube blank, and adopt the non-oxidation bright heat treatment process in to seek for comprehensive improvement in the wear resistance and acid dew point corrosion resistance of the product. After more than two months of repeated research and trial production, our laboratory simulated the relevant application environment in late September, using 50%H2SO4 test medium with setting the test temperature at 70℃±2, and the sample was soaked for 24h. The corrosion rate of the sample was shown in Table 1. At the same time, other performance indicators of the sample have been approved by the equipment manufacturers. At present, the seamless steel tubes for Gr.3 pre-heater has been delivered in batches. Our company will continue to follow up the use effect of the equipment and provide basic data support for the re-upgrade of steel tube performance.