TECHNICAL DATA SHEET GARDOBOND G 4040

Transcription

1 Phosphating process for iron materials to reduce sliding friction. Application by immersion. SCOPE Gardobond G 4040 is a phosphating process for iron materials on the basis of manganese phosphate. Gardobond G 4040 is applied by immersion. The phosphate coatings improve the wear resistance of moving parts. The weight of the manganese phosphate coating amounts to 4-20 g/m². Phosphate coatings produced by the Gardobond G 4040 process correspond to specification DIN 50942, code Fe/Mnph g f. During storage of the Gardobond G 4040 concentrate, a small amount of brown solids may settle at the bottom of the tank. This does not affect the quality of the product. CHEMICALS REQUIRED Gardobond G 4040 (make-up and replenisher solution) Gardobond-Additive H 7050 (accelerator) Gardobond-Additive H 7203 (neutralisation agent, manganese containing) OPERATION PROCEDURE Cleaning - rinsing - pickling (if required) - rinsing (if parts are pickled) - activating - phosphating - rinsing - rinsing - drying. PRE-TREATMENT Prior to phosphating remove all contaminants from the part surface. Cleaning and degreasing Cleaning and degreasing can be done with alkaline cleaners. Alkaline cleaners are supplied by us under the designation Gardoclean. Rinsing Carefully rinse with water after cleaning with alkaline cleaners. Rinsing after alkaline cleaning Immersion time : 1-2 minutes (repeated immersion) Bath temperature : without heating Operate the rinsing bath with fresh water supply. Page 1 of 5

2 Activating Immersion time : 1-2 minutes Bath temperature : room temperature - 50 C with pre-rinsing agent C without pre-rinsing agent For more detailed information, see the process instructions "Activating pre-rinse prior to phosphating on the basis of manganese phosphate with Gardolene V 6560 A + V 6561 B or Gardolene V 6560 A + V 6562 C". BATH MAKE-UP For 1000 litres of phosphating bath add 183 kg (140 litres) of Gardobond G This make-up corresponds to a concentration of 80 total acid points and approx free acid points. The phosphating bath is ready for use after thorough stirring (e.g. with oil free compressed air). After the material throughput the solution will show around 9-13 free acid points. BATH OPERATION Immersion time : 5-20 minutes Bath temperature : C Bath concentration : 80 total acid points 9-13 free acid points The ratio of free acid points : total acid shall be of 1 : > 6 The optimum working conditions are established by our Technical Service upon the start-up of the installation. BATH CONTROL The bath concentration is controlled by determining the total acid pointage, free acid pointage and iron pointage. Determine the total acid pointage and the free acid pointage several times per day. Iron separates from the bath solution during material throughput. Hence, the iron pointage should be determined at least once per day. Prior to sampling, fill the bath tank with water to operating level and thoroughly mix the solution. Total acid pointage Pipette 5 ml of phosphating bath into an Erlenmeyer flask. Dilute the solution with approx. 50 ml of distilled water and add drops of Test Indicator 2 (phenolphthalein). Titrate with Test Solution 1 (0.1 M sodium hydroxide) until the colour changes to red. Page 2 of 5

3 The ml of Test Solution 1 consumed multiplied by 2 indicates the total acid pointage. Free acid pointage Pipette 5 ml of phosphating bath into an Erlenmeyer flask. Dilute the solution with approx. 50 ml of distilled water and add 1 drop of Test Indicator 25 (dimethyl yellow). Titrate with Test Solution 1 (0.1 M sodium hydroxide) until the colour changes to yellow. The ml of Test Solution 1 consumed multiplied by 2 indicates the free acid pointage. Iron pointage Pipette 10 ml of phosphating bath into an Erlenmeyer flask. Dilute the solution with approx. 100 ml of distilled water and add 5 ml of Test Solution 12 (a 50 % sulphuric acid) and 2 g of Test Salt 21 (urea). Titrate with Test Solution 4 (0.02 M potassium permanganate) until the faint red colouring persists for approx. 20 seconds. The ml of Test Solution 4 consumed indicates the iron pointage. Iron points x factor 0.56 = g Iron(II)/L bath solution Max. value: 7-9 iron points (4-5 g of iron(ii) per litre of bath solution) ROUGHNESS When a lower surface roughness after phosphating is required, we recommend the use of our additive Gardobond-Additive H With the addition of 5 g/l to the phosphate bath, the pickling time and therefore the surface roughness will be considerably reduced. When the pickling rate decreases, the Gardobond-Additive H 7050 can be added again as described above. BATH REPLENISHMENT Total acid pointage The total acid pointage are maintained by adding Gardobond G For each total acid point consumed add per 1000 litres of phosphating solution 2.3 kg (1.8 litres) of Gardobond G Free acid pointage With a total of 80 total acid points, the free acid points should be of If the free acid points exceeds 13, add Gardobond-Additive H To reduce the acid pointage by 1 free acid point add per 1000 litres of phosphating bath 650 g of Gardobond-Additive H 7203, suspended in 10 times the amount of water. Page 3 of 5

4 Iron content The iron(ii) content can be kept constant by adding finely effervescent, oil-free compressed air or using a ventilation stirrer. After iron precipitation it may be necessary to desludge the solution. Before continuing the operation, titrate the total acid pointage and free acid pointage and replenish up to nominal value or neutralize with Gardobond-Additive H Optimum conditions can be worked out in co-operation with our Technical Service. DESLUDGING The sludge accumulated during phosphating or during the iron precipitation must be periodically removed. This is done via a settling tank or a suitable filtering equipment. It is also possible to pump the solution above the sludge into an empty rinsing tank. After returning the clear solution, fill the tank with water to operating level and stir thoroughly. Then determine the total acid points and free acid points and replenish with Gardobond G 4040 up to nominal value. RINSING Phosphating should be followed by a careful water rinse. 1st rinsing bath Immersion time : 1-2 minutes (repeated immersion) Bath temperature : without heating The first rinsing bath should be operated with fresh water supply. 2nd rinsing bath Immersion time : 1-2 minutes Bath temperature : C The second rinsing solution should be discarded several times. DRYING After draining, quick and thorough drying of the parts is required. We recommend driers with air circulation and fresh air supply. Part temperature: C AFTER-TREATMENT Protect the phosphated parts by lubricating or greasing within 24 hours after phosphating. Gardorol corrosion protection oils are supplied by us. Page 4 of 5

5 EQUIPMENT Gardobond G 4040 bath Bath tank General-purpose constructional steels to DIN EN 10025, with acid-proof rubber lining Chromium nickel steel, material number Chromium nickel molybdenum steel, material number Butyl rubber Heating elements Chromium nickel molybdenum steel, material number Fluorinated plastics Rinsing baths Bath tank and heating elements General-purpose constructional steels to DIN EN If pickling is required, the rinsing bath downstream of the pickling stage must be acid proof, e.g. made of general-purpose constructional steels to DIN EN with acidproof rubber lining. LABOUR & ENVIRONMENTAL PROTECTION For transport, storage, use and waste treatment of chemicals in concentrates or dilutions as well as bath solutions, the legal regulations have to be obeyed. Further specific information on the products are to be obtained from the EC Safety Data Sheets. For the used control agents the danger code on the label has to be followed. WASTE DISPOSAL All waste waters must be treated in accordance with national legislation and local regulations prior to discharge to the sewer. VH/1/07/CM GmbH/09/02-2/S2 5 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. Page 5 of 5