Salabova, and Jana
The effect of cryogenic treatment (CT) on the properties
of ledeburitic tool steels was investigated. CT is also used in conventional
heat treatment to improve mechanical properties and wear resistance and
decrease the amount of retained austenite.
The technology of CT
was developed in the 1960s and still elicits contrary scientific opinions
today. Some studies report that CT improves hardness, wear resistance, bending
strength, toughness, fatigue strength, etc., but some scientists do not agree.
Also, experts do not agree as to the main factor influencing results when CT is
applied – austenitizing temperature, cooling rate, quench temperature, holding
time, heating rate or tempering temperature.
The mechanism of fine carbide precipitation provides the most serious
discussion. When exactly do they form, and what is their effect on mechanical
properties? The steel grade treated by CT is also important. A significant
effect is seen for X153CrVMo12 (AISI D2) steel, and others are more disputable.
Our experimental work is focused on PM-produced, wear-resistant ledeburitic
tool steels. The goal is to determine the optimal CT (temperature and time)
that can help to prolong the life cycle of cold-work tools, keeping in mind the
economics of additional treatments. The investigation discovered many interesting
results but raised even more questions.
Source: Robin Schott