Date Published:Sep. 27. 2016
Vol.3 Functional Screw Surface Treatments Are Not Just for Corrosion Resistance
Hello. Nedzigon's back!
Are you familiar with all the possible surface treatments for screws?
Typically, Unichrome and nickel plating are used for corrosion resistance.
However, Vol.1 Thinking about "Galling and Seizing" talks about surface treatments for preventing seizing, reminding us that Surface treatments are used for purposes beyond corrosion resistance.
“Black Stainless Steel” Surface Treatment for Anti-Reflection
As the name suggests, Black Stainless Steel is a deep black finish for stainless steel surfaces which uses a passivation membrane 200 times thicker than normal.
It has an extremely low reflectivity of 1.5%, making it the optimal surface treatment for optical devices requiring diffused reflection prevention.
Additionally, Black Stainless Steel’s corrosion resistance is excellent, being 32 times that of SUS304 and 8 times even that of SUS316L.
>>Corrosion Resistance Comparison with Black Stainless Steel
Furthermore, because the film contains no impurities, outgassing in vacuum environments is minimal, and it can be used in vacuum equipment.
Teflon* Coating is Not Just for Seizing Prevention
For the effects of surface treatment on seizing prevention, see Vol.1 Thinking about "Galling and Seizing"
Among these, Teflon coating is a highly effective surface treatment for seizing prevention.
>>Comparison of axial force with regard to different surface treatments
However, Teflon coating's performance is not limited to this alone. It is also an excellent surface treatment for chemical resistance.
>> Chemical resistance of Teflon coating
*Teflon is a registered trademark of DuPont.
Decorative Surface Treatments
Surface treatments can also be used for decorative purposes.
As the name suggests, this is a surface treatment in which the material surface is coated in gold. Gold is a substance resistant to oxidation, widely used for decoration because its appearance is more constant.
Additionally, its characteristics also include good conduction of electricity and heat, making it an asset for electronic components.
Chrome plating has a glossy finish as well as high hardness with excellent wear resistance, making it suitable for long-term decoration.
Colored anodization soaks dye into the micropores of surfaces treatable with normal anodization to add color. Anodizing treatment is a surface treatment that produces oxidized film on aluminum surfaces, which means, unlike plating, it is almost totally resistant to peeling.
I’ll fill you in on more interesting surface treatments next time!
That's all for today.
Recommended Articles for You
Vol. 12 Back to Basics Series! Screw Reference Dimensions
This is a description of "stress corrosion cracking", a problem that frequently occurs but is difficult to detect. I, Nedzigon will discuss the causes, mechanism, and countermeasures, as well as screws that are resistant to stress corrosion cracking.
Vol. 9 Sudden Bolt "Delayed Fracture"
The phenomenon in which a bolt that has been fastened for some time suddenly breaks is called delayed fracture. This can cause a lot of hassle, as the exterior shows no deformation and yet the bolts suddenly break. Why does delayed fracture occur? Under what conditions does it occur? How can we prevent it? Nedzigon makes it all clear to you.
Vol.7 Screw Tightening Control Methods
Although fastening objects using the axial force generated from tightening is the main role of screws (bolts), in actual work, I think there are many people who control the torque by tightening with a torque wrench, because it is difficult to directly monitor the axial force, and so guarantee the axial force that way. However, there are other methods of control for tightening screws (bolts). These include those with only slightly greater axial force variation than with a torque wrench. Today, Nedzigon will tell you all about them.