Pearlite

About: Pearlite is a research topic. Over the lifetime, 6028 publications have been published within this topic receiving 65695 citations.

Wear and corrosion resistance of laser surface hardened structural steel

Abstract: CO 2 laser surface treatment in solid state has been performed on a CK60 structural steel. The laser energy density was lower than the melting threshold and only caused surface hardening. The observed heat affected zone (HAZ) ranged in depths of 50–430 μm. Microstructure of the HAZ was composed of needle, fine-grained martensite and small amount of pearlite and retained austenite. Microhardness values changed in areas of overlapping successive laser passes. Wear tests revealed the improved wear resistance of the laser treated specimens in comparison with the untreated one. Specimens laser treated using 0 and 38% overlapping ratios exhibited improved wear resistance. The corrosion resistance exhibited a tendency to decrease with increasing overlapping ratios. Among all specimens studied the one, which was laser treated with 0% overlapping ratio presented the best wear and corrosion behaviour.

Mathematical Model of Heat Flow and Austenite-Pearlite Transformation in Eutectoid Carbon Steel Rods for Wire

Abstract: A mathematical model incorporating both heat transfer and the transformation of austenite to pearlite in eutectoid carbon steel rods has been developed. A computer program based on the implicit finite-difference technique has been written which permits the temperature distribution and fraction of austenite transformed to be predicted as a function of cooling conditions, rod diameter and the transformation characteristics of the steel. The program takes into account the temperature-dependent heat transfer and thermophysical properties; and stresses the importance of the enthalpy of transformation. The model has been checked for internal consistency with theoretical equations, and model predictions have been compared to published industrial data for rod cooling in water at 100 °. The effect on the temperature distribution and fraction of austenite transformed of several variables,viz., rod diameter, starting temperature, heat transfer conditions, transformation characteristics and quenchant temperature, has been predicted using the model. The range of variables studied are typical of those found in industrial processes such as patenting and controlled cooling. Use of the model in the design of controlled cooling processes and in coping with problems such as segregation in wire rods is currently under study.

Microstructure-property relationships in pearlitic eutectoid and hypereutectoid carbon steels

Abstract: Fully pearlitic steels are of great importance in a number of extremely demanding structural applications, in large part because of their combination of strength and toughness. Strength and toughness are controlled by the microstructures developed in pearlitic steels, especially interlamellar spacing, pearlite colony size, and prior austenite grain size. This article reviews the effects of these microstructural features on the yield strength and toughness of fully pearlitic steels, the importance of hypereutectoid alloy compositions for increasing the strength of fully pearlitic steels.

Design of Advanced Bainitic Steels by Optimisation of TTT Diagrams and T0 Curves

Abstract: Cementite is responsible of the limited application of conventional bainitic steels, however it has been proof that cementite precipitation during bainite formation can be suppressed by the judicious use of silicon in medium carbon steels In this work, thermodynamic and kinetic models were used to design steels with an optimum bainitic microstructure consisting of a mixture of bainitic ferrite, carbon-enriched retained austenite and some martensite Using these models, a set of seven carbide free bainitic steels with a 03 wt% carbon content were proposed for manufacturing The work presented here is concerned with the microstructural and mechanical characterisation of the steels manufactured Except for the steel with the highest content of alloying elements, all the grades present the same microstructure composed of carbide-free upper bainite and retained austenite after hot rolling and a two-steps cooling Theirs tensile strengths range from 1600 to 1950 MPa while keeping a uniform elongation equal to 4% and a total elongation over 10% Regarding toughness at room temperature, they match quenched and tempered martensitic steels