Almost all commercial fasteners are made of carbon steel, alloy steel, and generally corrosion-resistant requirements, so the plating of the surface treatment must be firmly attached and not fall off during installation and removal. On the other hand, for threaded fasteners, the plating also needs to be thin enough that the threads can still be screwed together after plating. The plating generally has a lower temperature limit than the fastener material, so the operating temperature requirements of the fastener also need to be considered. The main purpose of surface treatment is aesthetics and corrosion protection. Since the main function of fasteners is to fasten parts and components, and the surface treatment also has a great impact on its fastening performance. Therefore, when selecting a surface treatment process, factors such as the torque and preload consistency of the fastener should be considered.

1. Several methods of surface
treatment for structural steel
fasteners?
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2. Almost all commercial fasteners are made of carbon steel, alloy steel, and generally
corrosion-resistant requirements, so the plating of the surface treatment must be firmly
attached and not fall off during installation and removal. On the other hand, for threaded
fasteners, the plating also needs to be thin enough that the threads can still be screwed
together after plating. The plating generally has a lower temperature limit than the fastener
material, so the operating temperature requirements of the fastener also need to be
considered. The main purpose of surface treatment is aesthetics and corrosion protection.
Since the main function of fasteners is to fasten parts and components, and the surface
treatment also has a great impact on its fastening performance. Therefore, when selecting a
surface treatment process, factors such as the torque and preload consistency of the
fastener should be considered.

3. 1. RUSPET is a kind of coating launched for
construction screws, its main performance
is strong anti-corrosion, can resist salt
spray time 500-1500H; colorful, can be
modulated according to the customer's
requirements of the color, to meet the
customer's requirements; the baking
temperature is relatively low, generally
controlled at 200 degrees Celsius or less,
especially construction screws or drill nails
class.
1.RUSPET

4. 2. Electro -ga l van i zed is the m ost com m on plating used f or
com m ercia l f as ten er s. I t is c hea pe r a nd has a b ett er a ppe ara nce,
and can be black or arm y green. Howeve r, its corrosion
resistance is average, and its corrosion resistance is the lowest
of the zinc plating (coating) layers . Generally, the neutral salt
spray test of electro -ga lva n ized zinc is with in 72 hours, and
there are also special sealers that m ak e the neutral salt spray
test up to 200 hours or m ore, but the price is expensive, 5 to 8
tim es of the general galvan ized . Electro -ga l van i zed process is
prone to hydrogen em brittlem ent, so 10.9 grade bolts are
generally not galvanize d treatm ent. Although you can use the
oven to rem ove hydrog en af ter plating, but because the
passivation f ilm will be destro yed at 60 ℃ or m ore, so the
hydroge n m ust be rem oved in the electroplat ing bef ore
passivation. T his is poor operabilit y and high processing costs.
In realit y, the average m anuf acturer will not initia te
dehydro gen at ion unless it is m andator y f or a specif ic custom er.
Electro-ga lvan ized f asteners have poor torque -preload
consistenc y and are unstable, and are generally not used f or
critical connections. In order to im prove the torque -pre loa d
consistenc y, it is also possible to im prove the torque -pre loa d
consistenc y by applyin g a lubricat ing substance af ter plating.
2.Electro-galvanized

5. 3.Phosphating is relatively cheaper than
galvanizing, but the corrosion resistance is
worse than galvanizing. After phosphating
should be coated with oil, the corrosion
resistance of its high and low with the
performance of the coated oil has a great
relationship. For example, after phosphating
coated with general antirust oil, neutral salt
spray test is only 10 ~ 20 hours. Coated
with high-grade antirust oil, up to 72 ~ 96
hours. But the price is generally 2~3 times
of the phosphating oil.
3.Phosphating

6. 4.It is a new type of anticorrosion coating with
zinc powder, aluminum powder, chromic
acid and deionized water as the main
ingredients. There is no hydrogen
embrittlement problem and the torque-
preload consistency performance is very
good. It is actually most suitable for high
strength fasteners with high corrosion
protection requirements, if chromium price
and environmental issues are not taken into
consideration.
4.DACROMET

7. Feel free to contact us if you
have other ways to handle this.
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