The purpose of the work was to assess the impact of construction factors on weldability of MSRB alloy. One conducted transvarestraint test, which allowed to assess welds' susceptibility to cracking under the conditions of forced strain of the casting, Fisco test which simulates welding under the conditions of strong stiffening of the weld, as well as Houldcroft test simulating variable strain of the weld. One concluded that the strain of castings is characteristic of the process of pad welding and welding. Assessment of susceptibility of MSRB alloy to cracking under the conditions of forced strain allows to determine the width of the high-temperature brittleness range (HTBR), critical strain speed of the weld CSS and critical temperature strain intensity CST. These parameters are the criteria of hot cracking of welds from MSRB alloy, therefore, they are indicators of the assessment of the alloy's weldability. Castings from MSRB alloys with constant rigidity should be classified as easily weldable. On the other hand, variable rigidity of the casting, resulting from e.g. diverse thickness of the walls, causes significant increase in the alloy's susceptibility to hot cracking.