PSI - Issue 59

Kozulin S. et al. / Procedia Structural Integrity 59 (2024) 391–398

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S. Kozulin et al. / StructuralIntegrityProcedia 00 (2019) 000 – 000

Fig. 2. Diagram of welding a through crack in the band of a rotary kiln using MESW CN with a consumable nozzle: 1 - power source; 2 - sub band casing; 3 - band; 4 - coil with electrode wire; 5 - canopy; 6 - consumable nozzle; 7 - device for supplying and draining cooling water; 8 - water-cooled insert; 9 - container with technological equipment and special tools; 10 - welding machine; 11 - control panel; 12 - rail trolley; 13 - control cabinet; 14 - roller support; 15 - furnace foundation support. Preparation of the edges for MESW CN was carried out with two parallel cuts in the tire body using an oxygen lance (Fig. 3, a). Local heat treatment (high tempering) of multi-pass welded joints was performed using a portable electric furnace (Fig. 3, c).

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Fig. 3. Fragments of edge preparation for MESW CN using an oxygen lance (a), correction of a through crack in a cement kiln tire with using the developed method (b) and heat treatment of the welded joint on the cement kiln body using a portable electric furnace (c). 3. Result and discussion Mechanical tests of the sections of welded joints that underwent auto-thermo-treatment revealed an improvement in their plastic properties. With respect to the base metal (steel 35L) properties listed in Table 2, the following characteristics of the weld metal are achieved: σ т ≥ 290 MPa, σ в ≥ 445 MPa, δ ≥ 30%, ψ ≥ 67%, and for the HAZ metal in the weld, δ ≥ 32%, ψ ≥ 70%, KCU ≥ 127 J/cm². The influence of the shape and location of the seams on their technological strength was studied, and a set of measures was developed to prevent the formation of hot cracks: - Multi-section execution of the non-detachable joint with separate seams to reduce the shrinkage of the weld metal, combined with positioning the weak plane in the direction coinciding with the vector of tensile stresses. - Reducing the level of tensile stresses during the crystallization of the metal bath due to the flexibility of separating inserts in the joint assembly, allowing for their displacement toward the weld and the transition of the insert metal into a plastic state due to heating.