Research On Property And Development Of Matching Welding Materials For Blower Impeller With Stainless Steel

With the rapid development of the country's industrialization process, blower is widely used in national production and life, medicine, paper making, textile, chemical fiber, glass, coal, grain, construction industry, tobacco, military, brewing, steel, power generation, cement, petrochemical and sewage treatment and other important industries. With regard to the blower, the impeller is a key component, the quality of impeller directly impact on the environment and the use of blower service life. In order to expand the field of application, the application of low-temperature condition in particular is very important. Therefore, for the sake of the overall quality and service life of blower, and the scope of application of existing materials, this paper will study three kinds of blower impeller of high-strength grade martensitic stainless steel (FV520 (B),0Cr13Ni5Mo, X21CrMoV121) base metal and welded joints of the performance.In this paper, three kinds of base materials of different mechanical properties have been studied by heat treatment, especially low temperature performance. The effects of different heat treatment processes on microstructure and low temperature properties of three kinds of base materials after different heat treatment were investigated by optical microscope, the impact fracture analysis, X-ray diffraction testing, hardness test and tensile test. The best low-temperature performance of three kinds of materials and the corresponding heat treatment process is selected by comparing material's overall performance. Then, a series of welding test were made. The results showed that the welded joints lack of toughness. Consequently, summary of existing shortcomings of welding material for low temperature application of the status quo, and put forward new ideas of match the welding material of the study.By the previous study, we can draw the following conclusions:(1) heat treated at 1000℃for 30min and then air cooled, tempered at 620℃for 2h and at 600℃for 2h secondary tempering,0Cr13Ni5Mo have a better comprehensive properties; (2)heat treated at 1050℃for 1h and then air cooled, transformated at 850℃for 2h and then oil cooled, aged at 600℃for 3h and then air cooled overall performance of FV520(B) is better, especially in low temperature toughness. Under this process the retained austenite content is higher; (3)X21CrMoV121 has a good low-temperature properties at 1050℃for 1h quenching and 720℃for 2h tempering.From FV520 (B) steel welding test study, we conclude that:the whole post-weld heat treatment process (ATH) is better than the performance obtained by welding pre-weld heat treatment and post-treatment process (TH) performance; The ideas of match-welding materials, is mainly to improve the welding joint toughness as a starting point, by acceding to improve the toughness of the alloy elements Ni, Mn, Mo etc and the Ti, B, Re micro-alloying elements, cleaning grain boundaries, grain refinement, without reducing the strength of joints while improving low-temperature toughness of deposited metal.