TP347H tube screen welding application

1Cr19Ni11Nb(TP347H) is a high-carbon yttrium-containing Cr-Ni austenitic stainless steel. Due to its stabilizing element Nb, it is resistant to intergranular corrosion and polysulfate-resistant intergranular stress corrosion. It is corrosive in acid, alkali, salt, etc. Its corrosion resistance is similar to Ti-containing 18 -8 austenitic stainless steel, so it is widely used in boilers, power generation, petroleum, chemical, synthetic fiber, food, paper and other industries. Since Nb is less prone to burn than Ti, this steel grade can be used as a weld core for welding chrome-nickel austenitic stainless steel. This steel grade has higher high temperature strength and better resistance to high temperature oxidation than the 316 series, so it is often used as a heat resistant steel. TP347H is mainly used in high-pressure boiler tubes and thermal power tubes. The temperature is between 625 and 649 ° C and 30 MPa. It is required that the steel will not fail after using 105H (determined by the specific use temperature and time).

The TP347H stainless steel pipe is delivered in a solid solution plus stabilized heat treatment state and has good weldability. The well-known domestic boiler factory TP347H pipe screen structure, pipe screen size Φ180mm*8mm+6mm*12mm. In order to improve production efficiency, submerged arc welding method is adopted, and Tiantai submerged arc welding material TFS-330+TW-347 is used for welding, which is suitable for high-efficiency automation (welding speed up to 850mm/min) production workshop. Tube screen welding assembly as shown below:

In actual production, the length of the pipe row is 16m. When the customer is welding on site, 4 welding torches are welded at the same time, the wire diameter is 2.0mm, and the welding speed is 850mm/min. The slag removal property is good, and the weld bead is well formed. Under the welding parameters, the weld joint comprehensive performance and corrosion resistance performance are still excellent, meeting the specification requirements, and realizing high-efficiency and high-quality welding.