Fig. 4

SEM analysis of 4 areas. 1 Rough surface—microthread area. 2 Rough surface—macrothread area. 3 Machined surface—microthread area. 4 Machined surface—macrothread area
SEM analysis of 4 areas. 1 Rough surface—microthread area. 2 Rough surface—macrothread area. 3 Machined surface—microthread area. 4 Machined surface—macrothread area