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Coating performance test - hydrogen embrittlement test

September 16, 2023

The early brittle fracture phenomenon of metallic materials under the combined action of hydrogen and stress is called hydrogen embrittlement. Methods for measuring hydrogen embrittlement include delayed failure test, slow bending test and other methods.


Delayed destruction test: this method is suitable for hydrogen embrittlement test of ultra-high strength steel. It is a sensitive and reliable test method. During the test, place the three notched rod-shaped specimens on the endurance strength testing machine or creep testing machine. At the time when the material breaks brittlely, if the three parallel test specimens do not break brittlely within the specified time, it is considered to be qualified.


Slow bending test: this method is more sensitive to low brittle materials. Attention should be paid during the test: if the test piece is deformed after heat treatment, it should be leveled by static pressure, stress should be eliminated before plating, and hydrogen should be strictly removed from the plated buckle. Before the test, a sufficient number of sample materials should be selected for blank testing to facilitate analysis of the test results and selection of the appropriate fracture shaft diameter.


Extrusion test: Place the washers to be inspected on screw rods of the same diameter. Set 10 to 15 pieces on each screw rod. Screw on nuts at both ends of the screw rod, then clamp them in a vise. Use a wrench to tighten the nuts to the opening of the washer. Squeeze flat. Leave it for 24 hours, then loosen it. Use a 5x magnifying glass to inspect the cracks and fractures of the tested gaskets. The results are expressed as brittle fracture rate. Brittle fracture rate = b/a Number of breaks).