INVESTIGATION OF HARDNESS AND IMPACT CHARACTERISTICS OF QUENCHED AND COLD TREATED DUCTILE CAST IRON
INVESTIGATION OF HARDNESS AND IMPACT CHARACTERISTICS OF QUENCHED AND COLD TREATED DUCTILE CAST IRON
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Date
2000-10
Authors
AUSE, TERVER
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Abstract
The effect of austentitizing temperature and quenching medium on
ductile cast iron in the as-quenched, cold treated and tempered condition was
investigated. The study was based mainly on hardness and impact tests.
Ductile cast iron speciemens were first given a normalizing beat treatment
before quenching. Normalized specimens were heated to five austentising
temperatures (800, 850, 900, 950 and 1000°C), soaked for one hour and
quenched in three media (water, brine and ice-water). Some of the specimens
were immediately subjected to hardness and impact test in the as-quenched
and tempered conditions while others were immediately subjected to cold
treatment at 20°C for two weeks in a domestic deep freezer after which
hardness and impact tests were conducted in both old and cold treated and
tempered conditions. The result shows that, ductile cast iron responded well to
hardening in the three media. However, ice-water gave the highest severity of
quench for all the austentitizing temperature used. Specimens quenched from
950oC in ice-water, brine and water had the highest hardness values of
511,490 and 480 HB respectively. Optimum hardening temperature for the
ductile cast iron was found to be between 900 - 950°C, while optimum
tempering temperature for adequate hardness for wear resistance was found to
be between 250 - 300°C then for strength and toughness it was found to be
between 350 - 400°C.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL IN PARTIAL
FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD
OF THE DEGREE OF MASTER OF SCIENCE IN
METALLURGICAL ENGINEERING
DEPARTMENT OF METALLURGICAL ENGINEERING
FACULTY OF ENGINEERING
AHMADU BELLO UNIVERSITY
ZARIA.
Keywords
INVESTIGATION,, HARDNESS,, IMPACT,, CHARACTERISTICS,, QUENCHED,, COLD,, TREATED,, DUCTILE,, CAST IRON