BS EN ISO 2376:2019 pdf download

BS EN ISO 2376:2019 pdf download.Anodizing of aluminium and its alloys – Determination of break down voltage and withstand voltage.
5.4 Current limiting resistor, 0.5 Mfl. in series with secondary winding of the transformer and the test electrode probe.
5.5 Voltage-measuring device, which gives r.m.s. values, expressed in volts.
5.6 Electrode probe, made from conducting material, suitably insulated (or handling purposes, free to move as required and adequately supported. The contact surface shall be spherical with a diameter of 3mm to 8mm and shall be maintained in a smooth, untarnished condition, The design of the probe shall be such that, when the spherical surface is placed on the surface of the anodized test specimen, the total force exerted on the coating is 0,5 N to 1,0 N (a probe ol mass 50 g La 100 g Is suitable).
5.7 Contact plate, for testing flat test specimens, having a smooth, biight, metallic surface, or a contact probe or clip which is capable of breaking through to the basis metal (Li).
5.8 Twisting machine, for testing round wire, having two sets of faws 400 mm apart, with one set of saws fixed, while the other set Is free to rotate. The ‘aws shall be mounted so as to prevent lateral movement of the jaws when the twisting operation is carried out (72).
6 Test specimen
6.1 Sampling
The test specimen shall be taken from a significant surface of the product, where the anodic oxidation coating formed thereon needs to satisfy the quality adapted to the application of the product The test specimen shall not be taken from the edges for possible distortion and/or non-uniformity.
Where it is impossible to test the product itself, a Lest specimen which is representative of the product may be used. In this case, the test specimen used shall he made from the same material and prepared under the same conditions of finishing as those used for the preparation of the product. The aluminium alloy, the manufacturing conditions (kind and temper of the material), and the surface condition before treatment shall be the same as those of the product. Pretreatment and anodizing shall be performed in the same bath and under the same conditions as the treatment of the product.
6.2 Treatment before testing
The Lest specimen shall he clean, free Ironi dirt. stains and other foreign matters. Any deposits or stains shall be removed with a clean, sort cloth or similar material which is wetted by an appropriate organic solvent such as ethanol. Organic solvents which can corrode the test specimen or generate a protective film on the test specimen shall not be used.
6,3 Size
The standard size of the test specimen should be 100 mm in length by 100 mm in width. The test specimen of a different size maybe used as agreed between the customer and the anodizer.
7.1.2 Breakdown test
Starting at zero, increase the voltage uniformly at a rate not exceeding 25 V/s until the voltage drops suddenly (indicating breakdown voltage of the coating). It is necessary to dean the contact surface of the probe after any breakdown has occurred, and it is essential to return the voltage to zero after each determination and particularly before cleaning the probe.
Carry out a minimum of live tests and record the lowest value and the mean value obtained. Alternatively, ascertain whether or not any value falls below a predetermined breakdown voltage.
7.1.3 WIthstand voltage test
Starting at zero, increase the voltage uniformly to the specified voltage and maintain that voltage for the specified period of time. If electric breakdown does not occur within the specified time period, then the voltage indicates the withstand voltage. If the voltage drops within the specified period of time. then that is due to electric breakdown.
It is necessary to clean the contact surface of the probe after each determination, and it is essential to return the voltage to zero after eadi determination and particularly before cleaning the probe.
The voltage and the period of time should be specified by the customer and the anodizer.