Strengthening railroad rails by isothermal quenching to lower bainite

Metallurgist ◽  
2013 ◽  
Vol 56 (9-10) ◽  
pp. 779-786 ◽  
Author(s):  
Yu. A. Samoilovich
Keyword(s):  
Lower Bainite ◽  
Isothermal Quenching ◽  
Railroad Rails

Microstructures and Properties of a Bainite and Martensite Dual-Phase Cast Steel Fabricated by Combination of Alloying and Controlled Cooling Heat Treatment

2005 ◽  
Vol 475-479 ◽  
pp. 93-96 ◽  
Author(s):  
Ye Hua Jiang ◽  
Rong Feng Zhou ◽  
Dehong Lu ◽  
Zhen Hua Li
Keyword(s):  
Heat Treatment ◽  
Cast Steel ◽  
Residual Austenite ◽  
Lower Bainite ◽  
Manganese Steel ◽  
Isothermal Quenching ◽  
Dual Phase ◽  
Controlled Cooling ◽  
Carbide Particles ◽  
Better Than

A bainite/martensite dual-phase cast steel was fabricated by a process of combination of alloying with Si and Mn elements and controlled cooling heat-treatment. Its microstructure was consisted of fine lower bainite with carbide particles precipitated homogeneously, martensite and a little residual austenite. Because of the good match of hardness and impact toughness, its impact wear performance was a little better than that of the isothermal quenching steel, and much better than that of high manganese steel such as Mn13.

scholarly journals The Role of Bainite in Wear and Friction Behavior of Austempered Ductile Iron

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 767 ◽  
Author(s):  
Fulin Wen ◽  
Jianhua Zhao ◽  
Dengzhi Zheng ◽  
Ke He ◽  
Wei Ye ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Ductile Iron ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Lower Bainite ◽  
Austempered Ductile Iron ◽  
Isothermal Quenching ◽  
Micro Hardness ◽  
Friction Behavior ◽  
Upper Bainite

The austempered ductile iron was austenitized at 900 °C for 1 h and quenched in an isothermal quenching furnace at 380 °C and 280 °C, respectively. This paper aims to investigate the effects of bainite on wear resistance of austempered ductile iron (ADI) at different loads conditions. The micro-structure and phase composition of ADI was characterized and analyzed by metallographic microscope (OM), X-ray diffractometer (XRD) and scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS). The results showed that the volume fraction of retained austenite in ADI is reduced with the increase of austenitizing temperature. Meanwhile, the two kinds of ADI samples showed varied wear resistance when they were worn at different loads conditions. For wearing at a load of 25 N, the wear resistance of ADI mainly depends on matrix micro-hardness. Thus, ADI with lower bainite structure has higher hardness and leads to better wear resistance. When wearing at a load of 100 N, the increase of micro-hardness of upper bainite was significant. As a consequence, upper bainite showed superior friction and wear behavior. It was also found that the form of wear behavior of ADI changed from abrasive wear to fatigue delamination as the wear load increased from 25 N to 100 N according to the observation on worn surface.

Analysis of Microstructure and Mechanical Properties of Bearing Inner Ring

2014 ◽  
Vol 496-500 ◽  
pp. 777-780
Author(s):  
Mei Li Qi ◽  
Xiu Juan Zhao ◽  
Yan Tao Wang ◽  
Peng Tao Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Stress ◽  
Average Diameter ◽  
Axial Direction ◽  
Rolling Bearing ◽  
Lower Bainite ◽  
Width Ratio ◽  
Isothermal Quenching ◽  
The Core ◽  
Microstructure And Mechanical Properties

This article selects GCr18Mo steel to make an inner ring of rolling bearing. After isothermal quenching heat treatment, microstructure and mechanical properties are tested. The results show that microstructure and hardness from the surface to the core is uniform. The compositions are lower bainite and carbide, and both of them are small. The length-width ratio of lower bainite needle is about 10, and the average diameter of carbide in is 0.33μm. The hardness ranges from the surface to the core is between 715 HV and 755 HV, the average hardness of the inside and outside surface is 59.9HRC. Stress state of the surface is compressive stress and axial compressive stress is greater than the one of the hoop. Compressive stress in axial direction is about 588MPa, which is about 390MPa in the direction of the ring. After polishing, compressive stress in axial direction is about 483MPa, which is about 231MPa in the direction of the ring.

Identification of Phases in Alloy Steels after Quenching and after Isothermal Quenching

2012 ◽  
Vol 186 ◽  
pp. 301-304 ◽  
Author(s):  
Julita Smalc-Koziorowska ◽  
Elżbieta Jezierska ◽  
Wiesław Świątnicki
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Morphological Characteristics ◽  
Lower Bainite ◽  
Heat Treatments ◽  
Isothermal Quenching ◽  
Transmission Electron ◽  
Alloy Steels ◽  
Diffraction Patterns ◽  
Means Of Transmission

The purpose of the work is the analysis and the identification of phases in alloy steels after various heat treatments by means of transmission electron microscopy. We have investigated the phases formed during austenitising followed by quenching with various rates or by isothermal quenching, as martensite, upper and lower bainite. In order to identify the phases, we used their morphological characteristics and the kind of orientation relationship between the given phase and the austenite. We concluded that the identification of phases occurring in steels after various heat treatments may be performed in a clear manner according to their morphological features combined with the diffraction patterns analysis as observed by transmission electron microscopy.

Microstructure and Properties of Isothermally Quenched High Boron White Cast Iron

2010 ◽  
Vol 457 ◽  
pp. 207-212
Author(s):  
Jian Jun Zhang ◽  
Yi Min Gao ◽  
Jian Dong Xing ◽  
Sheng Qiang Ma ◽  
Wan Qin Yan ◽  
...  
Keyword(s):  
Cast Iron ◽  
White Cast Iron ◽  
Fracture Morphology ◽  
Lower Bainite ◽  
Isothermal Quenching ◽  
Microstructure And Properties ◽  
The Matrix ◽  
High Boron ◽  
Matrix Transforms ◽  
Cast Condition

Microstructure and properties of isothermally quenched high boron white cast iron were investigated in this paper. The results show that the microstructure of high boron white cast iron is mainly composed of many continuous and netlike eutectic borides, pearlite and ferrite under as-cast condition. The microhardness of Fe2B ranges in 1200-1600HV whose value seems to approximate that of (Fe,Cr)7C3–type carbide (HV1200~1800) in high chromium white cast iron. After isothermal quenching, the matrix transforms into lower bainite in which carbide precipitations are arranged in parallel rows at an angle of 60 deg to the long axis of the plates, but the morphology of boride remains nearly unchanged compared with its as-cast condition. Moreover, precipitation particles with the size of about 1~4 μm can be found in the matrix of isothermally quenched high boron white cast iron. Impact fracture morphology of isothermally quenched high boron white cast iron indicates that fracture propagated more easily through boride/matrix interface than through matrix.

Isothermal quenching of cold-heading dies

1970 ◽  
Vol 12 (2) ◽  
pp. 164-165
Author(s):  
G. K. Savinovskii
Keyword(s):  
Isothermal Quenching

Cementite Precipitation of a H21 Tool Steel after Hot Compression and Double Temper

2014 ◽  
Vol 1043 ◽  
pp. 154-158
Author(s):  
Meilinda Nurbanasari ◽  
Panos Tsakiropoulos ◽  
Eric J. Palmiere
Keyword(s):  
High Temperature ◽  
Applied Stress ◽  
Tool Steel ◽  
Hot Deformation ◽  
Lower Bainite ◽  
Precipitation Behavior ◽  
Transformation Mechanism ◽  
Tempered Martensite ◽  
Bainite Transformation ◽  
Precipitation Behaviour

The cementite precipitation behavior in the martensite and banite of the H21 tool steel under high temperature axisymmetric compression test and double temper was investigated. The main purpose on this work is to develop a better understanding regarding the transformation mechanism of bainite and martensite in a H21 tool steel. The selected deformation temperatures were 1100 oC and 1000 oC and the double temper process was carried out at 650 oC for 1 hour respectively. The results showed that the cementite was sensitive to the stress. The applied stress has affected the Fe3C precipitation behaviour by decreasing the number of variants carbides in tempered martensite and decreasing the number of a single variant carbides in tempered lower bainite. The results were in agreement with a displacive mechanism of martensite and bainite transformation. It was also found that hot deformation temperatures selected in this work have the same contribution in decreasing number of variant carbides in tempered martensite and decreasing number of single variant carbides occurred in tempered lower bainite.

Creeping of Railroad Rails

1921 ◽  
Vol 84 (1) ◽  
pp. 361-385
Author(s):  
J. A. L. Waddell
Keyword(s):  
Railroad Rails
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