| Abstrakt: |
Thin-walled welded joints of corrosion-resistant high-alloy steels are used in various industries for the manufacture of critical structures. The tendency to reduction in the mass of products in order to save costs and energy resources makes it relevant to find the ways to solve the problem of welding such joints, including also the use of concentrated power sources such as laser radiation. The use of laser technologies in welding thin-walled joints of high-alloy steels may be applied not only at the manufacturing stage but also at the stage of repair. The high cost of treatment of such materials makes the problem of finding the ways to avoid the formation of defects in such welded joints relevant. At the same time, it is urgent to develop technologies for repair of thin-walled welded joints made of high-alloy steels. The article is devoted to the solution of this task namely by using laser welding and surfacing technologies. According to the results of visual, radiographic testing and metallographic examinations, the parameters of thin-walled welded t-joints of aIsI 321 steel were evaluated, namely: geometry, ripple, presence of craters, pores, their quantity, sizes, mutual position and other parameters provided by DSTU EN ISO 13919-1:2015 standard. The analysis of the obtained data made it possible to find the presence of individual defects of welded T-joints in the form of single pores, chain of pores, lacks of fusion, depression of the weld, lacks of penetration, shrinkage cavities and cavities in the crater, undercuts, excess of convexity. The procedure for their elimination and prevention of their formation was developed. It was established that thin-walled welded t-joints of aIsI 321 steel after repair according to the proposed procedure have mechanical characteristics at the level of defect-free welded joints and amount to 670-717 MPa. This allows recommending the proposed procedure to perform the operation of repair of such joints when eliminating defects in the form of burn-outs. [ABSTRACT FROM AUTHOR] |
