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Акты контроля герметичности методом «керосин на мел».

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With less penetrant inspection companies around, it may seem that penetrant testing has gone by the wayside and some new, improved processes have taken over. This is far from the truth; penetrant testing has not disappeared, nor has a new, improved process replaced it. Penetrant testing is still being used in more applications and industries than ever before.

Penetrant testing, often called PT or liquid penetrant, was originally called the oil-and-whiting method when it was first used on locomotive parts such as rail car wheels, rods, axles and crankshafts. Parts were first cleaned in boiling caustic soda, then dried and immersed in a tank of oil. The penetrant used was heavy lubricating oil (600W), often thinned with kerosene. Used motor oil also was used to give a darker contrast. Dwell or penetration time ranged from a few hours to a couple of days. The oil was removed with rags dampened with kerosene. After the parts were cleaned and dried, they were painted with a mixture of whiting, or chalk, diluted in denatured alcohol. Where cracks existed, the oil seeped through the white coating, indicating the presence of discontinuities. This was useful only for detecting large, deep cracks. Control over mixing solutions or how long they were applied was left to the operators.
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