Power Plants
The main sources of pollution in the thermal power is SO2, usually to remove SO2 by FGD systems. In the FGD system due to the corrosive effects of the continuous use of lime wash produce outside, in addition to the entire system during long-term use will have many attached to the metal surface of the deposit. And thereby generate pores and crevice corrosion, so we have to choose between one and the substrate (base metal) one for the FGD system - Super Affinity and has good corrosion resistance of welding consumables. There are two basic reasons:① The first reason: Because of the microscopic structure of the entire welding area is very similar to casting, it is a branched crystals. Its chemical micro segregation and its branch-like crystal structure is proportionate, while its micro segregation to another hole and crevice corrosion and is closely related to the region, welding consumables for the FGD system must contain good corrosion resistance elements, such as chromium, molybdenum, tungsten and so on. ② The second reason: We use alloy and steel composite board manufacturing container, has super affinity function using lots of weld material is more important, because the composite sheet steel base material will be diluted solder layer anti-corrosion effect strong elements. Due to the above reason, we often adopt NiCrMo-14 to replace the C-276 has welded with steel C-276 weld overlay. At the same time in the production of this type of FGD systems typically employ high efficiency welding process and requirements for all-position welding, this result makes little situation after welding diluted preservative effect is very good. Corrosion mechanism described here in some large-scale waste incineration system is equally applicable.
The important part of Nuclear power is the steam generator and reactor. The steam generator is a giant with thousands of branch U-tube heat exchanger tube plate. All of these heat exchanger tube is fully inserted in the tube a huge parallel plate having a diameter of 4,500mm, thickness of 500mm. The seams of all these tubes and plates are required dense welded together. Used to weld these joints opening consumables is an alloy containing 30% chromium NiCrFe-7 (INCONEL 52). The main use of this material in order to prevent the intergranular water environment arising from stress corrosion cracking.