CHARACTERIZATION OF THE PROEUTECTOID CEMENTITE NETWORKS OBSERVED IN THE SAE 1092 WIRE ROD STEEL GRADE
Currently, the trend around the world is to produce lighter wires with higher strength for long span bridge applications and the automobile tire industry. Increasing the carbon content in the steel is the most common way to achieve higher strength in these applications. The chosen steel in this study was SAE 1092. The advantage of this steel is its higher strength but the disadvantage is the formation of a brittle phase. In this type of hypereutectoid steel, the proeutectoid cementite precipitates along the austenite grain boundaries prior to the formation of the pearlite. As the amount of carbon increases above the eutectoid point, more of this brittle phase precipitates. At the beginning of this work, two proeutectoid cementite networks were identified; one in the center and the other close to the surface of the wire rod. Electron Backscattered Diffraction (EBSD) was used to crytallographically define that proeutectoid cementite forms at certain grain boundaries of a given orientation. Dilatometric tests were carried out to verify the minimum cooling rate necessary to avoid the formation of the proeutectoid cementite. It was also used to verify the influence of the environment on the transformation of austenite and the precipitation of the proeutectoid cementite. Industrial experiments were also carried out in order to determine what conditions should be used to produce wire rods with large diameters and free of proeutectoid cementite network.
Advisor:Dr. C. I. Garcia; Dr. A. J. DeArdo; Dr. I. Nettleship
School:University of Pittsburgh
School Location:USA - Pennsylvania
Source Type:Master's Thesis
Keywords:materials science and engineering
Date of Publication:10/14/2004