A DIN 933 bolt and a GOST 7798 bolt look almost the same: a hexagon head, a metric thread and the same strength class marking. But they are not always interchangeable.
Thread
A DIN 933 bolt is threaded along the whole shank. For most lengths, GOST 7798 specifies a thread on only part of the shank, and the plain part takes the shear. The closest European equivalent of such a bolt is DIN 931.
Geometry and accuracy
GOST 7798 covers bolts of accuracy class B (normal accuracy). The two standards set different tolerances, and for some diameters the across-flats size differs too. Before substituting, check the dimensions against the tables of both standards.
What they share
Strength classes are marked the same way: 5.8, 8.8, 10.9. Mechanical properties for each class are specified comparably, so bolts of the same class are equivalent in material.
Can you substitute
If the bolt works in tension only, the substitution usually causes no problems. But if the shear plane passes through the thread, the joint’s load capacity drops. So agree on replacing GOST 7798 with DIN 933 with the designer before purchasing.