Preparation of steel substrates before application of paints and related products
BS ISO 8502-15:2020 pdf free.Preparation of steel substrates before application of paints and related products一Tests for the assessment of surface cleanliness Part 15: Extraction of soluble contaminants for analysis by acid extraction.
Choose test areas which are representative of the entire surface. Otherwise, it is important to select test areas where metal loss or pitting is observed, and on or around metal welds, as these are the areas where salts will be most prevalently concentrated.
6.2 Extraction by patch or sleeve by injection
6.2.1 Take an adhesive patch or sleeve (5.1) of a suitable size (see Table 1). Remove the protective paper; for the patch remove the punched-out material (see Figure 1).
6.2.2 Press the adhesive side of the patch or sleeve against the test surface (see Figures 2 and 7) in such a way that the minimum amount of air is trapped in the compartment in the patch.
6.2.3 Fill the syringe (52) with solvent (5) (see Figure 3).
NOTE The volume of solvent needed to fill the patch compartment is proportional to the compartment area and normally amounts to 2,6 x 103 mI/mm2 ± 0,6 x 10-3 mI/mm2. The volume of solvent needed to fill the sleeve compartment is proportional to the compartment area and normally amounts to 10,0 x 103 mI/mm2 ± 0,6 x 10-s mi/mm2 (10 ml for S-1000 sleeve).
6.2.4 Insert the syringe needle at an angle of about 300 to the test surface near the outer edge of the patch or sleeve, so that it passes through the adhesive foam body of the patch or sleeve into the compartment formed between the elastomer film and the test surface (see Figure 4).
If the patch or sleeve is in a position which makes access to the patch compartment difficult, bend the syringe needle as required.
6.2.5 Inject the solvent, ensuring that it wets the whole of the test surface (see FigureA).
If necessary, to avoid air remaining trapped in the patch compartment, carry out the injection in two steps as follows: inject half of the solvent. When required, evacuate the air through the needle by reverse operation of the syringe. Remove the needle from the patch or sleeve. Holding the syringe with the needle pointing upwards, expel the air. Reinsert the needle into the compartment and inject the remainder of the solvent.
6.2.6 After a suitable period, to be agreed between the interested parties, suck the solvent back into the syringe (see Figure 5). During this period, agitate the solution in the patch without removing the syringe needle from the patch or sleeve. The solution can be agitated by reinjecting the solvent into the compartment. Then suck the solvent back into the syringe cylinder at least four times or massaging the patch or sleeve to create solvent movement over the test surface.
6.2.7 Transfer the solvent to a suitable vessel for analysis (see Fignre_6) as required for the analysis method.
6.2.8 During steps 62 to 6.2.7. it is essential that no solvent be lost from the cell or syringe, due for instance to inferior-quality materials or improper handling of the materials. If any solvent is lost, the solution obtained shall be rejected.
6.2.9 On completion of step 62.7, clean and rinse the syringe so that it can be reused. A bent needle is best left as it is until it becomes necessary to straighten it or bend it further.
6.3 Extraction by sleeve by pre-filling
6.3.1 Take an adhesive sleeve (5.1) of a suitable size (see Table 1). Remove the protective paper and straighten the sleeve.
6.3.2 Prefill the sleeve with the required volume of solvent (5) and adhere the patch to the surface
without loss of solvent (see Figure 7).
NOTE The volume of solvent needed to fill the sleeve compartment is proportional to the compartment area and normally amounts to 10,0 10-3 mI/mm2 ± 0,6 x 10-3 mI/mm2.
6.3.3 Position the sleeve such that all solvent in the sleeve is in contact with the surface.
6.3.4 During a suitable period of time, to be agreed between interested parties, or recommended by the manufacturer of the test equipment, agitate the sleeve several times by massaging the solvent on the surface. After the time period, let the sleeve hang down in order for the solvent to flow into the compartment of the sleeve.
6.3.5 Carefully remove the sleeve from the surface. Retain the solvent for further analysis.
6.3.6 During steps 6.32 to 6.3.5. it is essential that no solvent be lost from the sleeve, due for instance to inferior-quality materials or improper handling of the materials. If any solvent is lost, the solution obtained shall be rejected.
6.3.7 Record the temperature of the steel surface to the nearest 0,5 °C using the contact thermometer (SA). The temperature shall be over 0 °C to avoid ice on the surface.
6.4 Blank test
To check cleanliness of the cells, blank tests shall be performed in advance for each batch.
For the blank test, a piece of clean glass, to which the adhesive patch will adhere, shall be used and water of the same type as to be used for testing. The same procedure as in 6.2 or 6.3 shall be followed.
If the background interference is significant the cause shall be investigated and, if possible, eliminated.
If the background interference introduced by the adhesive cell is significant, reproducible and cannot be eliminated, a blank test shall be performed in parallel to each test and the background subtracted from the field quantitative measurements in order to report a net surface contamination value. If this procedure is followed, it shall be stated in the report.
7 Analysis
After sampling, the extract is analysed as agreed between the interested parties. Suitable methods of analysis are chlorides with the ion detection tube as described in ISO 8502-5 or other methods of chemical analysis. The analytical differences between the extraction methods covered in this method and those of ISO 8502-6 are discussed in Reference [5]. The origins of the extraction by cells are described in Reference [4].
NOTE Methods of analysis are not covered by this document.
8 Test report
The test report shall contain at least the following information:
a) a reference to this document (i.e. ISO 8502-15:2020);
b) the solvent used;
c) the volume of solvent injected or pre-filled;
d] the total volume of solvent after dilution;
e) the total time of contact between the solvent and substrate;
f) the temperature during steps 6.2.3 to 6.2.7 or 6.3.2 to 6.3.5 of the procedure;
g) the type and size of extraction cell used: patch or sleeve;
h) the manufacturer’s batch number of the patch or sleeve used;
i] the date of the test.BS ISO 8502-15 pdf free download.Preparation of steel substrates before application of paints and related products