Abstract: A rotary impeller assembly is for a fluid machine and includes a support member having an outer surface and blades connected to the support member. Each blade includes first and second integral portions, the blade first portion having a first thickness and being spaced from the base surface and the blade second portion is disposed against the support member outer surface and has a second thickness. The second thickness is substantially greater than the first thickness such that the blade has greater stiffness proximal to the support and a lesser stiffness generally distal from the support. Preferably, the blades are connected with the support welds between each blade sidewall and the support member. Further, each blade first portion is sized such that the blade first thickness is maintained in a significant area of the blade spaced from the weld(s) so as to allow blade flexure away from the weld.

Abstract: A method of welding and an assembly formed thereby, according to which a first member is formed with a first thickness and a second thickness greater than the first thickness. The first member is welded to a second member and a toe is formed in at least one wall of the first member in that portion of the first member having the increased thickness.