Parkerizing
Agent DH-180(to be sprayed)
1.
General
introduction
DH-180 is a
fast parkerizing agent with a
low-temperature and low-dregs character. It
forms a thin yet solid parkerizing film on
the surface of the iron-steel work pieces
through chemical treatment. The parkerizing
film can remarkably improve the attachment
of paint and the resistance against erosion.
The finished surface will be much more shiny
and refined.
The
agent consists of components in 4 packets:
DH-180A(for preparing the tank)
DH-180B(for reinforcing)
Neutralizer NT-525
Activator AC-1
2.
Technical procedures
Degreasing --- cleaning in water ---
cleaning in water --- (surface adjustment)
--- parkerizing --- cleaning in water
---cleaning in water --- cleaning in pure
water
Degreasing ---cleaning in
water --- acid pickling --- cleaning in
water --- (surface adjustment and
neutralizing --- parkerizing --- cleaning in
water --- cleaning in pure water
Degreassing and rust
removing --- cleaning in water --- cleaning
in water --- surface adjustment ---
parkerizing --- cleaning in water(hot water)
Choose one of the above
procedures. When it has been gone through,
put the work piece into an oven to be dried.
3.
Preparing the parkerizing tank(1000L)
a)
Let the tank contain water up to 80% of the
total volume.
b)
Put in 30kg of DH-180A, and stir well.
c)
Take 2.67kg of NT-525 and dilute it with 20L
of water, and then add them into the tank.
d)
Pour in more water to make up the total
volume 1000L.
e)
Heat the liquid to the temperature required,
and then test the acidity.
f)
Add 0.38kg of activator and stir well before
treating the work pieces.
4.
Treating conditios
General acidity --- 14-15pt
Free acidity --- 0.5-0.8pt
Density of the activator --- 1.5-2.5pt
Temperature --- 45-55°C
Time duration --- 2-3 minutes
5.
Supplement and adjustment(1000L)
As
the density keeps changing during the
treating process, density tests should be
made at regular intervals to maintain
density within the required range. Every
1.74kg of DH-180B added may increase the
general acidity by 1 pt.
But in case of
overflow causing a loss of the treating
liquid, water and DH-180A must be added
to
adjust the general
acidity. Every 2.07kg of DH-180A will raise
the general acidity by 1pt.
Free acidity may be
lowered by neutralizer --- On condition that
only small pieces or no pieces are being
treated and the parkerizing liquid is as hot
as over 45°C, or that the DH-180B has been
put in too much, then free acidity will go
up over 1.2pt. In that case, neutralizer is
needed for regulating the liquid. Every 160g
of neutralizer NT-525 can lower the free
acidity by 1pt.
Activator ---
Activator in the liquid is consuming even
while no work pieces are being treated. So
its density should be tested in the process
of treatment and extra activator be added to
maintain the required density. Every 150g of
activator AC1 can increase the acidity by
1pt.
6.
Testing methods
General
acidity --- Transfer 10ml of the liquid with
a suction pipet into a 250ml beaker and add
5 or 6 drops of phenolphthalein. Titrate
with NaOH(0.1N). When the color turns from
colorless to pink, it is the end of the
titration. The number of ml used is the
value of general acidity.
Free acidity --- Transfer 10ml of the liquid
with a suction pipet into a 250ml beaker and
add 4 or 5 drops of bromophenol blue
indicator. Titrate with NaOH(0.1N). When the
color turns from yellow to blue or purple,
it is the end of the titration. The number
of ml used is the value of free acidity.
Density of activator
--- Fill a fermentation tube with the
treating liquid. Add 2-5g of sulphanilamide.
Block the tube, turn it upside down and
shake it vertically. Then let it stand still
for 2 minutes. The volume of the gas
produced as indicated by the scales will be
the density of the activator. One scale
means one pt.
7. Materials of the
apparatuses
The parkerizing tank
should be made of stainless steel or carbon
steel. The heat exchnager, the sprayer
nozzle, the piping and the pump should be
made of stainless steel.
8. Equipment
maintenance
The best way to rid
the tank of deposits is to pump the whole
lot of the liquid into a deposit tower or
deposit pool, and then return the clean
liquid to the parkerizing tank.
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