The formation of bainite in steel is generally accompanied by an enrichment in carbon of the adjacent austenite which can become remarkably stable as evidenced by its very slow transformation rate and its very lowM s point. This paper presents the results of a study of this residual austenite in an SAE-9262 steel. Both the carbon content and the amount of retained austenite have been
Bainite Transformation Characteristics of High-Si Dec 26, 2017 · The transformation kinetics of the high-Si hypereutectoid bearing steel is much more sluggish compared to that of the AISI 52100 bearing steel. This implies that the bainite transformation is obviously decelerated by the addition of 1.3 wt.% Si in hypereutectoid bearing steel, consistent with the results presented in Ref. [ 36 ].
In summary, effect of carbonitriding on microstructure of SAE 52100 steel revealed ultrafine carbides and nitrides based precipitates. Case depth of ~0.5 µm is observed from temper resistance behaviour of carbonitrided steel at 573 and 623 K. The dependence of the volume fraction of retained austenite on the tempering temperature is demonstrated.
Effect of Partial Martensite Transformation on Bainite Isothermal bainitizing of high carbon steel is used to obtain exceptionally high mechanical characteristics together with near zero distortion during heat-treating. Such heat-treatments are often carried out at temperatures close to but above the martensite start temperature, where transformation kinetics are unfortunately very sluggish. The formation of a small amount of martensite prior to
Effects of Spheroidized Microstructure on Bainite SAE 52100 steel is the most widely used material for ball and roller applications. Some studies have demonstrated that 52100 steel with a certain amount of lower bainite is superior to that produced in a single-martensite condition in terms of mechanical properties [1-3]. The current studies on lower bainite transformation in 52100 steel primarily focus on microstructure and kinetics [4-8]. J. Chakraborty
Fig. 8 Cooling dilatometric curve (a) and a part of its differential curve within the temperature range of bainitic transformation (b) corresponding to a cooling rate of 1 C s-1 for undeformed steel - "Dilatometric study of phase transformations in advanced high-strength bainitic steel"
Isothermal study of bainitic and martensitic The transformation kinetics of the upper and lower bainitic reactions were determined for four commercial quenched and tempered steels, AISI 4130, AISI 4140, D6AC and AMS 6416 (300-M). Their chemical compositions are given. The kinetics of the bainite reaction below the martensite start temperature (M/sub s/) was determined.
Microstructural Renement of Bainite and Martensite for duplex microstructure, obtained in SAE 52100 steel after austenitizing at 1223 K (950 C) for 15 minutes followed by austempering at 543 K (270 C) for Fig. 1(a) Optical micrograph showing bainitic sheaves along with martensitic laths/needles formed after partial austempering and quenching. (b) Optical micrograph showing smaller and thinner
A series of experiments were conducted to determine the isothermal kinetics of the austenite to bainite transformation in 52100 steel at 230 and 240 oC. The steel was austenitized at 850 oC for 30 minutes and quenched in liquid salt.
The Kinetics of the Isothermal Bainite Formation in 1%C-1 The kinetics of isothermal bainite formation at 483 K, 503 K and 533 K in a bearing SAE 52100 steel (1,01% C 1,36% Cr 0,32% Mn 0,25% Si (wt.%)) is investigated theoretically and experimentally. It is found that the bainite formation becomes significantly slower with decreasing temperature. To interpret the results, a physical model with a concept of reconstructive approach proposed
Time-dependent synchrotron X-ray diffraction on the We have studied the decomposition kinetics of the metastable austenite phase present in quenched-and-tempered SAE 52100 steel by in situ high-energy synchrotron X-ray diraction experiments at elevated temperatures of 200235 C under a constant tensile stress. We have observed a continuous decomposition of austenite into ferrite and cementite.
Translate this pageIn addition, the bainitic formation in SAE 52100 steel was characterized using the theory of kinetic phase transformation. The activation energies of lower bainite and upper bainite microstructure were found to be 4.72 × 10 4 J/mol and 6.07 × 10 4 J/mol with frequency factors of 23.03 (1/s) and 273.65 (1/s), respectively.