Rivet holes

In the days of riveted boilers, concentration of caustic took place through the seepage or leakage of BW into rivet holes or seams. Sodium nitrate was the classic SCC inhibitor and was applied at 20 to 40% of the caustic alkalinity (2P-M). It is still used today in certain older facilities, although alternative organic-based inhibitors are now available. 

Drill fuze body for safety pin pnertia type only) and install either an electric or inertia type detonator in the fuze body. Secure in place with shims, spacer blocks, epoxy etc. Install safety pin and retainer if one is to be used. Reassemble the fuze and body sections with both epojo and a pair of screws or pop rivets (holes B). Maintain proper alignment during reassembly to avoid a wobbly, inaccurate projectile. 

Thickness of plate, inches Diameter of rivet holes, inches Efficiency, per cent Pitch, inches Thickness of straps, inches... 

Due to the force applied, the fastener is shifted under shear between the two sheets, and the eccentricity of the force introduces a considerable momentum locally into the joint. The sheets undergo local bending. When the load is increased, the rivet holes are additionally deformed into an oval shape, especially in the thin aluminum face layer of a sandwich panel. The deflection of the joint even leads to small separations between the sheets in the overlapping region. 

The biggest field of applicatiOTi for this process is the manufacturing of rivet holes in the aerospace industry where 100,000 up to 1,000,000 rivet holes have to be machined for one aircraft. Due to material combinations like CFRP aluminum, CFRP titanium, or CFRP aluminum-titanium, one tool has to cope with total different material behavior during one-process step (Janssen 2003). 

There might be stress concentrations around, say, rivet holes, or at sharp angles. 

In most environments, the chemical that is reduced is either dissolved oxygen or hydrogen ions in acids. In anaerobic conditions (no oxygen or air present), some bacteria (anaerobic bacteria) can thrive. These bacteria can provide the reducible chemicals that allow corrosion to occur. That is how the limited corrosion that was found on the hull of Titanic occurred. Figure 2.23 shows a rusticle removed from the hull of Titanic. This combination of rust and organic debris clearly shows the location of rivet holes and where two steel plates overlapped. 

Because filiform corrosion prqngates on structural areas that are either clad or coated with organic paint, this type of material deterioration can read extensively before it is detected by airoaft maintenance personnel. In typical cases, filiform corrosion develops around fastener holes on airfimne sheet structures. Paint blistering around the rivet holes is a characteristic feature of this type of corrosion. Documented case histories of filiform corrosion of various components include the following. 

RivelecI or Belted Structures. Riveted aircraft structures have a high vulnerability to exfoliation corrosion because the rivet holes provide an unobstructed pathway for coirosive electrolytes to reach m allic airfiume materials, especially aluminum. 

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