Estimation of fatigue properties of 35NCDV12 alloy steel under chromium coating using the staircase method

الملخص EN

In this paper, the experimental estimation of the fatigue strength and the standard deviation for the 35NCDV12 alloy steel have been found using the Staircase (up and down) method.

The specimens divided into two groups.

The first group contains 15 non-chromium specimens and the second group contains 15 hard chromium specimens.

The thickness of the chrome is about (100 to 120 microns).

The fatigue or endurance limit has been determined for each group and then compared with that estimated from S-N (Whler) curve for the 35NCDV12 alloy steel.

The results show that the endurance limit of the chromium specimens is decreased to a ratio about 60 % from those non-chromium specimens.

This proves that the chromium plating increases the wear and corrosion resistance of the metals and decreases the fatigue strength and endurance limit of those metals.

In addition, the results show that the staircase method is very useful testing compared with S-N curve for estimation the endurance limit without a large number of specimens.