AS ISO 3452.6 pdf download

AS ISO 3452.6 pdf download.Non-destructive testing — Penetrant testing
3 Low temperature penetrant testing
3.1 General principles The general principles of ISO 3452-1 shall apply unless otherwise stated in this part of ISO 3452 or in the manufacturer’s instructions. Qualification tests are carried out by the manufacturer and if products are used within the stated range, no further tests are needed on site. . 3.2 Technical principles Depending on the temperature range, some specific problems might be encountered: moisture, or even ice, on the test object; b] lower evaporation rate of solvents and of non-aqueous wet developers than at higher temperatures; c) when spray cans are used, pressure and spray quality may be affected; . d] some penetrants may precipitate. In such a case, tests shall be carried out within the standard temperature range (10 °C to 50°C) ifthe penetrants are to be used in the working temperature range. 3.3 Safety precautions All relevant European, national and local regulations pertaining to health and safety, environmental requirements etc. shall be observed. Depending on the temperature range, some specific rules shall be enforced: . a) when heaters are used (either to warm up the test object, materials or the work environment), precautions shall be taken not to have vapours or spray of materials in contact with flames or hot surfaces; b] users shall wear clothes and gloves able to protect them from contact with very low temperature parts. Gloves used shall allow for applying materials without impairing the test; c] in very low temperature environment, some pieces of equipment ( pens, cameras, etc.] may not properly work. Action shall be taken, either to keep them at an acceptable temperature until use (for instance by keeping them under clothing, close to the user’s body) or by using equipment capable of functioning in such an environment. 3.4 Reference blocks/test panels Care shall be taken while using reference block/test panels. It could be tempting to put these panels in a freezer, and to take them out when they have reached the targeted temperature for testing materials. Doing so places cold parts in contact with a warmer atmosphere, causing moisture to condense on these parts and the temperature to rise very quickly. Therefore, tests shall be carried out in “real conditions”: parts, users and testing materials are either outside or in a“climatic room”in which the temperature and humidity is capable of duplicating real conditions. 3.5 Viscosity and penetrant testing If it is the case that the lower the temperature, the higher the liquid or gas viscosity, then note that higher viscosity is not a drawback to penetrant testing. Capillary effect is far more powerful than the effect of the viscosity – very viscous, even jellified penetrants, can lead to very good crack detection.
4 Low temperature penetrant testing process
4.1 General rules The following rules apply: a) surface and discontinuities shall be free of any contaminant, even those stemming from the surface preparation; . b) penetrant is applied on the part as per the most convenient means; . c) when dwell time has elapsed, excess of penetrant shall be wiped from the surface with clean, lint- free rags or cloths and a penetrant remover in accordance with the manufacturer’s recommendation (water should be avoided due to low temperatures); d] low temperature penetrant testing generally is not carried out in installations. A non-aqueous wet (solvent-based) developer shall be sprayed on the test object. In low temperature conditions, solvents evaporate far slower than usual. Therefore, care shall be taken that the solvent evaporation time be sufficient to achieve accurate indications; e] viewing conditions shall comply with the requirements of ISO 3059. 4.2 Special requirements 4.2.1 Surface preparation Within the +10。C to -5。C range, the main trouble comes from water, either as liquid (moisture), frost or even ice. Water is detrimental to the process. To get rid of it: a} gently warm the surface for several minutes to make water evaporate from discontinuities; and/or b] use a volatile, water soluble solvent, such as acetone or isopropyl alcohol (generally degreasers used before penetrant applications are hydrocarbon-based and do not in any way remove water); c) allow some minutes for evaporation, ensuring evaporation does not cool down the surface of the part enough to have water condensing on it again. When the temperature is lower than -5 °C, check that there is no frost or ice. Any frost or ice shall be removed.