Technical Data Sheet
GARDOBOND® Z 3400
Zinc phosphate pre-treatment
Scope
Gardobond Z 3400 is a phosphating process on the basis of zinc phosphate for iron materials and
serves as a pre-treatment prior to cold forming. It is particularly suited for tube drawing.
Gardobond Z 3400 is applied by immersion.
The weight of the phosphate coating amounts to 1 - 6 g/m².
Physical properties
Gardobond
Z 3400 A
Gardobond
Z 3400 E
Gardobond
Z 3400 E1
Appearance: .
.
.
Density (20ºC):
.
.
pH value (concentrate, 20ºC):
pH value (75 g/l, 20ºC):
.
Flash point (DIN 51755 / 53213):
colourless liquid
1,55 g/cm³
.
<1
.
.
1,8
.
.
non-flammable
colourless liquid
1,55 g/cm³
.
<1
.
.
n/a
.
.
non-flammable
colourless liquid
1,45 g/cm³
<1
n/a
non-flammable
Other chemicals required
Gardobond-Additive H 7004 (accelerator)
Gardobond-Additive H 7030 (18% hydrogen peroxide solution)
Gardobond-Additive H 7141 (neutralising agent)
Process sequence
Cleaning (if necessary) - rinsing (if cleaning must be done) - pickling - rinsing - prerinsing phosphating - rinsing - neutralizing - after-treatment (depending on the type of cold forming) - drying
(if necessary)
Bath make-up
For 1000 litres of phosphating solution, add:
Variant 1
Variant 2
Gardobond Z 3400 A
50 litres (80 kg)
53 litres (85 kg)
Gardobond-Additive H 7004
0.6 litres (0,8 kg)
1.3 litres (1,5 kg)
Gardobond-Additive H 7141
-
1,6 litre (2,2 kg)
[cont]
A company of mg chemical group Dynamit Nobel
GARDOBOND Z 3400
[Bath make-up – cont]
Immediately before the first throughput of material through Gardobond Z 3400 variants 1 and 2 add
Gardobond-Additive H 7004; for Gardobond Z 3400 variant 3 add Gardobond-Additive H 7138, diluted
in 10 times the amount of water.
Phosphating solutions made-up according to specification correspond to the following concentrations:
Gardobond Z 3400 variant 1:
28 total acid points
8 accelerator points
Gardobond Z 3400 variant 2:
28 total acid points
15 accelerator points
These are the normal make-up strengths. The Chemetall Field Support Engineer can recommend the
precise conditions for any given installation.
Bath operation
Immersion time (minutes)
Temperature
Total acid points
Accelerator points
Variant 1
Variant 2
3 … 10
50 … 60ºC
22 … 33
3 … 10
3 … 10
30 … 40ºC
23 … 33
10 … 20
Bath control
Testing chemicals required
Indicator Solution #1 (phenolphthalein)
Testing Powder #18 (urea)
Testing Solution #1 (0.1N sodium hydroxide)
Testing Solution #6 (0.1N potassium permanganate)
Testing Solution #14 (50% sulfuric acid)
Testing Solution #44 (30% potassium oxalate)
5% disodium hydrogen phosphate solution
The concentration is controlled by determining the total acid points, the phosphate points and the
accelerator points.
If necessary the total acid points HEHN are determined.
Fill the tank with water to operating level and stir thoroughly.
Total acid points
Pipette 10 ml of phosphating solution into an Erlenmeyer flask. Dilute with approximately 50 ml of
distilled water and add 10 drops of Indicator Solution #1. Titrate with Testing Solution #1 until the
colour changes to pink.
The ml of Testing Solution #1 consumed indicate the total acid points.
Total acid points HEHN
Pipette 10 ml of bath solution into an Erlenmeyer flask, add approx. 20 ml of a 5 % disodium
hydrogen phosphate solution and approx. 50 ml of water as well as 10 - 15 drops of Indicator Solution
#1, titrate with Testing Solution #1 until the colour of the solution changes to pink.
The ml of Testing Solution #1 consumed indicate the total acid points HEHN.
[cont]
[Bath control – cont]
Page 2/5
GARDOBOND Z 3400
Phosphate points
The determination of phosphate points allows an exact control of the bath composition. The frequency
of the control of the phosphate points will be determined by the Field Support Engineer upon start-up.
Prior to the determination of the phosphate points replenish the total acid points to nominal value.
Pipette 10 ml of bath solution into an Erlenmeyer flask, add 20 ml of Testing Solution 44 and 10 - 15
drops of Indicator Solution #1, titrate with Testing Solution #1 until the colour of the solution changes
to red.
The ml of Testing Solution #1 consumed indicate the phosphate points.
Accelerator points
The accelerator points should be determined several times a day and at least prior to start-up and
following interruptions of the process.
Pipette 100 ml of bath solution into an Erlenmeyer flask, add 20 drops of Testing Solution #14 and
titrate with Testing Solution #6 until a faint red colour persists for about 20 seconds.
The amount of ml of Testing Solution #6 consumed indicates the consumption "A".
Pipette 100 ml of bath solution into an Erlenmeyer flask, add 20 drops of Testing Solution #14 as well
as 2 g of Testing Powder #18 and let it rest for approx. 3 minutes. Titrate with Testing Solution #6 until
a faintly red colour persists for about 20 seconds.
The amount of ml of Testing Solution #6 consumed indicates the iron points.
Titration "A" - iron points = accelerator points
Replenishment
Total acid points
The total acid points is maintained by adding Gardobond Z 3400 E or Gardobond Z 3400 E1. The
optimum replenisher solution will be determined by the Field Support Engineer.
For each total acid point consumed add, per 1000 litres of phosphating solution:
1.0 litres (1,7 kg) Gardobond Z 3400 E, or
0.85 litres (1.38 kg) Gardobond Z 3400 E1.
Accelerator point
The accelerator points are maintained by replenishing the bath solution with Gardobond-Additive H
7004 in the case of Gardobond Z 3400 variants 1 and 2.
For each accelerator point consumed add 0,07 litres (0,08 kg) of Gardobond-Additive H 7004 in the
case of Gardobond Z 3400 variants 1 and 2 per 1000 litres of phosphating solution.
Phosphate points
In order to obtain the correct titration ratio for the bath replenishment, divide the total acid points by
the phosphate points.
[cont]
Page 3/5
GARDOBOND Z 3400
[Replenishment – cont]
If the titration ratio is between 1.4 and 2.8 replenish with Gardobond Z 3400 E or Gardobond Z
3400 E1.
If the titration ratio is below 1.4 replenish with Gardobond Z 3400 A.
For each total acid point add 1.6 litres (2.6 kg) Gardobond Z 3400 A per 1000 litres of bath solution.
If the titration ratio is above 2.8 replenish with Gardobond Z 3400 E or Gardobond Z 3400 E1; in this
case please contact our Technical Service.
Iron content
If more than 0.5 iron points are titrated or if the amount of iron points is about equal to the
consumption A, the bath solution has absorbed iron which has to be eliminated with the addition of
Gardobond-Additive H 7030 diluted in 10 times the amount of water.
Then the bath has to stand at operating temperature for 2 - 3 hours without throughput of material.
After this add anhydrous sodium carbonate according to the following table and diluted in a 10 %
aqueous solution:
For 1000 litres of bath solution
Iron points
Iron (II) content / g/l
1
2
3
4
5
10
20
30
40
over 40
0.056
0.112
0.168
0.224
0.280
0.560
1.120
1.680
2.240
over 2.240
Gardobond-Additive
H 7030 / litres
sodium carbonate/ kg
0.091
0.053
0.182
0.106
0.274
0.159
0.365
0.212
0.456
0.265
0.912
0.530
1.824
1.060
2.735
1.590
3.647
2.120
new bath make-up necessary
Desludging of the bath may become necessary after iron precipitation.
Prior to further operation, the total acid points and the accelerator points should be determined and
replenished up to their nominal value.
Desludging
We recommend to remove the sludge accumulating during phosphating by means of a filter. To this
effect the tank bottom has to be equipped with pointed cones.
If not, the sludge must be removed from time to time. To this effect fill the phosphating solution into a
settling tank or pump the solution above the sludge into a rinsing or reserve tank.
After returning the clear solution fill the tank with water to operating level and stir thoroughly. Then
titrate the total acid points and replenish to their nominal value.
Bath replenishment after desludging
For each total acid point consumed add 1.6 litres (2.6 kg) Gardobond Z 3400 A per 1000 litres of bath
solution.
Page 4/5
GARDOBOND Z 3400
Equipment materials
Tank
Chromium nickel steel, material No. 1.4541
Chromium nickel molybdenum steel, material No. 1.4571
General-purpose constructional steels to DIN EN 10025, with rubber lining
General-purpose constructional steels to DIN EN 10025, lap-welded, limited suitability
Heating element
Chromium nickel molybdenum steel, material No. 1.4571
Water-cooling jacket
Fluorocarbon resins
General information
Chemetall supplies a wide range of chemical products and associated equipment for cleaning,
sanitising, descaling, paint and carbon removal, metal protection and forming, paint denaturing and
non-destructive testing. Field Support Engineers are available to advise on specific problems and
applications.
Chemetall also supplies products within the glass, polymer, fine chemical and aerospace fields.
Safety and handling guidance
Before using the product it is important that this complete document, together with any relevant safety
data sheet(s), have been read and understood. The safety data sheet(s) will advise on all
precautions, safety equipment and procedures necessary in the safe use and disposal of the product.
Environmental guidance
All local and national regulations on the transport, storage, use and waste treatment of chemicals in
concentrated or diluted form, or as working solutions, plus any by-products and contamination
occurring as part of the process, must be obeyed.
All waste waters must be treated in accordance with national legislation and local regulations prior to
discharge to the sewer.
LC Juni 2002
Page 5/5
 registered trademark
The above data have been compiled to the best of our knowledge on the basis of thorough tests and with regard to the current state
of our long practical experience. No liabilities or guarantee deriving from or in connection with this leaflet can be imputed to us.
Reproduction, in whole or in part, only with our express permission.
Chemetall PLC
Denbigh Road, Bletchley, Milton Keynes MK1 1PB
Tel: (01908) 649333 • Fax: (01908) 373939
e-mail: ukinfo@chemetall.com • www.chemetall.com