Fatigue of 0.55C-1.72Si Steel with Tempered Martensitic and Carbide-Free Bainitic Microstructures

• High-Si spring steel was heat treated in three different ways: Quenching and tempering at 460 °C to obtain a tempered martensite microstructure, and austempering at 300 and 350 °C, respectively, to obtain two different carbide-free bainitic microstructures. In the steel austempered at 350 °C, both the bainite lath thickness and retained austenite content were higher than those of the steel austempered at 300 °C. Rotating-bending fatigue tests were done in order to evaluate the effect of each heat treatment on the high-cycle fatigue behavior of the steel. When the austempering temperature was 300 °C, the endurance limit was increased by 25% despite a 5% reduction in tensile strength when compared with that of the quenched and tempered steel. The relationship between endurance limit [Rfat (50%)] and ultimate tensile strength (Rm) was higher for the austempered samples in comparison with that of the quenched and tempered material. Therefore, it is believed that the presence of retained austenite affects the relationship between endurance limit and tensile strength.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Annan materialteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Other Materials Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Teknisk mekanik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Applied Mechanics (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Tribologi (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Tribology (hsv//eng)

Nyckelord

Engineering Materials

Materialteknik

Hållfasthetslära

Solid Mechanics

Machine Elements

Maskinelement

Centre - Centre for High Performance Steel (CHS)

Centrumbildning - Centrum för högpresterande stål (CHS)

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