Effect of Trace Elements (Boron and Lead) on the Properties of Gray Cast Iron

Kandula Ankamma

doi:10.1007/s40033-013-0031-3

Abstract

In the present work an effort has been made to correlate the “Effect of trace elements (B and Pb) on the tensile strength, hardness and microstructure of gray cast iron”. These elements have a significant effect on the properties and microstructure of gray cast iron. These elements are deliberately added to study their effect on properties and microstructure. Boron up to 0.02 % in gray cast iron showed an improvement in tensile strength and hardness values. While beyond this amount it shows a decreasing trend, due to the formation of type B and type D graphitic structure. Lead in gray cast iron shows a decreasing trend in tensile strength and hardness values, even if present in trace amount, due to the formation of spiky or mesh type graphite.

Highlights

Outstanding castability, good combination of mechanical and physical properties, low cost and simplicity in production make gray cast iron an excellent foundation material for many engineering components such as cylinder block, cylinder head, oil cooler cover, brake drum etc
To avoid trace element contamination in charge materials, all bought in scrap should be examined prior to the stockpiling so that undesirable charge materials can be removed
Microstructure of base gray cast iron consists of type A graphitic

Summary

Introduction

Outstanding castability, good combination of mechanical and physical properties, low cost and simplicity in production make gray cast iron an excellent foundation material for many engineering components such as cylinder block, cylinder head, oil cooler cover, brake drum etc. The effect of boron and lead on the mechanical properties and graphitic structure at trace level on gray cast iron are studied. Elements normally present as trace amounts in gray cast iron can have a significant effect on properties and graphitic structure. It is possible for boron to be present in the iron up to 0.055 %, with disastrous results in terms chill, cracking problems in thin sections, decrease in tensile strength and undesirable graphite forms such as formation of type D graphite in gray cast iron [5,6,7,8,9]. The specimens for metallography and hardness were cut from the fractured tensile test specimens

Hardness test

Metallography

Results and Discussions

Conclusions