SYSTEM FOR MEASUREMENT-EVALUATION AND MODELLING OF COOLING IN HEAT TREATMENT
Main researcher
: LIŠČIĆ, BOŽIDAR (57402) Assistants
AGANOVIĆ, IBRAHIM (134)
FILETIN, TOMISLAV (76170)
Type of research: applied Duration from: 04/30/91. to 04/30/95. Papers on project (total): 10
Institution name: Fakultet strojarsva i brodogradnje, Zagreb (120) Department/Institute: Department of materials science FACULTY OF MECHANICAL ENG. & NAVAL ARCHITECTURE Ivana Lucicća 5, 10000 ZAGREB Address: Ivana Lucića 5 City: 10000 - Zagreb, Croatia
Communication
Phone: 385 (0)1 512-135
Fax: 385 (0)1 514-535
Summary: This system includes adequate hardware and software for:
measurement, recording and evaluation of the cooling (quenching) intensity
in heat treatment, especially when hardening steels in real industrial
conditions. The main part of the hardware is the LIŠČIĆ - NANMAC probe
instrumented with three thermocouples for measurement of temperature at the
very surface, below the surface and in the center of the 50 mm Dia bar
cross-section. Based on the own Temperature Gradient Method the computer
aided program calculates and displays graphically: the course of the heat
flux density as a function of time and a function of the probe's surface
temperature as well as the course of the temperature difference between the
center and the surface of the probe. Using the following criteria: - qmax =
maximun heat flux density - tqmax = time from start of quenching upto the
moment when qmax occurs - Tqmax = surface temperature of the probe at
which qmax occurs - int from t0 to tx (q dt) = integral below the heat flux
density curve in a certain time interval, every quenching process for
every quenchant, every quenching conditions, and every quenching technique
may be evaluated realistically and compared with another quenching or
cooling process in respect of: resulting dept of hardening, thermal
stresses and the susceptibility to deformation and cracking when hardening.
Additional program modules enable the calculation of the course of heat
transfer coefficient by using of which calculation of cooling curves is
possible at arbitrary points of the cross-section of long cylindrical parts
of different diametars and plates of different thicknesses. By
superimposing of the calculated cooling curves onto the CCT diagram of the
relevant steel, prediction of structural constituents and resulting
hardness after quenching is possible.
Research goals: Objectives and expected contribution of this work
are the following: - To test the universality of the described system and
method i.e. the possibility of its application to different quenching media
(oils, aqueous polymer-solutions, hot salt-baths), to different quenching
conditions (bath temperatures, agitation rates), and different quenching
techniques (direct quenching, martempering). - To verify the criteria for
evaluation of the quenching intensity for different quenching media and
quenching conditions in respect to depth of hardening. - To elaborate a
computer program for PC with all necessary modules, supplement existing
data files with experimental data, and to create a data file of
CCT-diagrams for different steels. - To compare the measured and calculated
surface temperatures of the probe. The expected contribution of this work
from one side is the creation of the computer aided system for measuring,
recording and evaluation of the quenching intensity that is universally
applicable in different quenching conditions in the heat treatment
practice, and from the other side development of methods for modelling
(prediction) of structural constituents and hardness after hardening.
COOPERATION - INSTITUTIONS
Name of institution
: Prirodoslovno-matematički fakultet
(Matematički odjel) Sveučilišta u Zagrebu Type of institution: University/Faculty Type of cooperation: Systematic exchange of information City: 10000 - Zagreb, Croatia
Name of institution
: Department of Mechanical Engineering,
Michigan State University, East Lansing, MIchigan, USA Type of institution: University/Faculty Type of cooperation: Systematic exchange of information City: East Lansing, USA, Michigan
Name of institution
: Department of Mechanical, Industrial and
Nuclear Engineering, University of Cincinnati, Cincinnati, Ohio, USA Type of institution: University/Faculty Type of cooperation: Systematic exchange of information City: CINCINNATI, Ohio, USA Other information about the project.