Welding of thick-walled NCu30+Q345 composite steel plate (4)
(4) The heat treatment stress is to obtain uniform temperature on both sides of the inner and outer walls and the weld. When the temperature is constant, the temperature difference between any two points in the heating range should be <10 °C.
(5) During the heat treatment, the flange surface should be protected by insulation material to prevent damage to the flange surface or deformation.
(6) After the heat treatment is completed, the Brinell hardness test is carried out. The test part is one place for each longitudinal joint, ring joint and joint fillet weld. Each part includes a weld point, a heat affected zone and each side of the base metal. 5 points, Brinell hardness ≤ 220HBW.
(7) After the heat treatment is completed, the surface of the composite layer is subjected to pickling passivation treatment.
6. Welding procedure qualification
After the test piece is welded, the welded test piece is heat-treated according to the heat treatment process of Article 5, and 100% RT flaw detection is performed according to JB4730.2-2005. The qualified base layer is evaluated according to JB 4708-2000, and the multi-layer is evaluated according to Appendix B of JB/T4756-2006. The evaluation results are shown in Table 3.
7. Welding product test board
(1) A pair of product test plates are welded at the end of the longitudinal section of the first section of the reaction product separation tank.
(2) After the visual inspection of the test plate weld is carried out, 100% RT inspection is carried out according to the requirements of JB/T 4730.1~6-2005, and the qualified standard is Grade II.
(3) The test plate after passing the RT test is subjected to post-weld heat treatment together with the reaction product separation tank, and then the mechanical properties test is carried out according to the relevant requirements of JB 4744-2000.
8. Conclusion
Using this welding process, the manufacturing task of the equipment was successfully completed, ensuring the construction period and welding quality. It proves that the welding process and welding measures are feasible and provides valuable experience for the welding of this material.
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Welding machine is a device designed to provide an electric current to joint materials, usually metals or thermoplastics, by causing coalescence (most often by melting small parts of them).
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