Analysis of mechanisms for hardening constructional steels by structure parameters

Contribution of different hardening mechanisms into tensile strength of carbon and low alloy steels has been evaluated on the basis of analysis of research papers and own experimental studies. It has been found out that solid solution and grain boundary strengthening provide the most contribution to tensile strength of normalized steel, whereas in structural low alloy steel low alloy steel the role of dispersion strengthening is noticed (21,4 %) along with the above strengthening components. It has been shown that thermal and chemical treatment of St5 grade steel leads to around 27,6 % growth of dislocations strengthening in rolled steel in case of accelerated cooling of hot wrought austenite

Analysis of mechanisms for hardening constructional steels by structure parameters

Contribution of different hardening mechanisms into tensile strength of carbon and low alloy steels has been evaluated on the basis of analysis of research papers and own experimental studies. It has been found out that solid solution and grain boundary strengthening provide the most contribution to tensile strength of normalized steel, whereas in structural low alloy steel low alloy steel the role of dispersion strengthening is noticed (21,4 %) along with the above strengthening components. It has been shown that thermal and chemical treatment of St5 grade steel leads to around 27,6 % growth of dislocations strengthening in rolled steel in case of accelerated cooling of hot wrought austenite

Plasma hardening of heavily loaded parts of soil-cutting machines

The influence of plasma hardening on hardening processes of heavy-duty and, therefore, wear parts of working elements of soil-cutting machines has been studied. It is shown that surface plasma hardening of ploughshare made of structural steel 65Mn in the hardened zone with thickness of 0,8 mm leads to formation of gradient-layered (mixed) structure consisting of finely dispersed mixture decay products of fine-grained austenite with variable microhardness in the range of 760 – 395 HV. It is confirmed that the creation of gradient-layered structure and features of its formation after the surface plasma treatment are explained by ultrahigh heating and cooling rates, unattainable with traditional methods of heat treatment

Plasma hardening of heavily loaded parts of soil-cutting machines

The influence of plasma hardening on hardening processes of heavy-duty and, therefore, wear parts of working elements of soil-cutting machines has been studied. It is shown that surface plasma hardening of ploughshare made of structural steel 65Mn in the hardened zone with thickness of 0,8 mm leads to formation of gradient-layered (mixed) structure consisting of finely dispersed mixture decay products of fine-grained austenite with variable microhardness in the range of 760 – 395 HV. It is confirmed that the creation of gradient-layered structure and features of its formation after the surface plasma treatment are explained by ultrahigh heating and cooling rates, unattainable with traditional methods of heat treatment