TY - JOUR ID - TI - ESTIMATION OF FATIGUE PROPERTIES OF 35NCDV12 ALLOY STEEL UNDER CHROMIUM COATING USING THE STAIRCASE METHOD ( تخمين خصائص الكلل لسبيكة الفولاذ OF 35NCDV12 تحت التغطية الكرومية بأستخدام طريقة السلم ) AU - Dr. Nabil N. Swadi * PY - 2012 VL - 12 IS - 1 SP - 73 EP - 88 JO - Iraqi journal of mechanical and material engineering المجلة العراقية للهندسة الميكانيكية وهندسة المواد SN - 20761819 AB - 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. Thespecimens divided into two groups. The first group contains 15 non-chromium specimens and thesecond group contains 15 hard chromium specimens. The thickness of the chrome is about (100 to120 microns). The fatigue or endurance limit has been determined for each group and thencompared with that estimated from S-N (Whler) curve for the 35NCDV12 alloy steel. The resultsshow that the endurance limit of the chromium specimens is decreased to a ratio about 60 % fromthose non-chromium specimens. This proves that the chromium plating increases the wear andcorrosion resistance of the metals and decreases the fatigue strength and endurance limit of thosemetals. In addition, the results show that the staircase method is very useful testing compared withS-N curve for estimation the endurance limit without a large number of specimens.

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