Holiday Testing On Stainless Steel

Holiday detection using the wet sponge method is restricted to coatings that are up to 500 μm 20 mil thick.

Holiday testing on stainless steel. It is also conducted on coating systems applied to steel that is in contact with soil and or con stantly wet. Holiday test method detecting pores and cracks with high voltage this method can be used to find defects in insulating coatings complying with numerous norms including astm d4787 and astm d5162. Spark testing is a method of determining the general classification of ferrous materials.

Holidays tests work on the concept of electrical conductivity. The premature corrosion of a substrate is usually due to a coating failure which is largely from flaws in the finished coating. These sparks can be compared to a chart or to sparks from a known test sample to determine the classification.

I do not have any experience in very dry desert environments but generally there will be enough moisture and salts present in concrete to make it conductive. 1 2 method a is designed to detect holidays such as pinholes and voids in thin film coatings from 0 025 to 0 254 mm 1 to 10 mils in thickness using ordinary tap water and an applied voltage of less than 100 v d c. 1 1 these test methods cover the apparatus and procedure for detecting holidays in pipeline type coatings.

This substrate can be metallic steel stainless steel aluminium or concrete with sufficient moisture content to make it conduct the electrical current drawn from the unit when a flaw is detected. When testing pipelines inspectors sometimes just drag the ground cable along on the ground since both soil and concrete conduct electricity. Using a high voltage detector on steel or conductive substrates is generally straightforward.

Holiday detection is typically performed on coating sys tems designed for critical service such as immersion or chemical storage. Holiday testing allows the detection of even the smallest coating flaws invisible to the naked eye. Holiday testing allows the detection of even smallest coating flaws invisible to the naked eye.

Holiday tests are used to detect holes known as holidays or breaks in a coating. Holiday test is used to detect holes known as holidays or discontinuities in a coating. These tools called holiday detectors are portable devices that are swept across the coated surface.