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The effect of carbon content on selected mechanical properties of model Mn-Cr-Mo alloy steels during tempering
| Content Provider | Semantic Scholar |
|---|---|
| Author | Dziurka, Rafał Pacyna, Jerzy |
| Copyright Year | 2013 |
| Abstract | Civilizational progress has a strong focus on improving properties of construction materials and their production technology. Due to the fact that so far, the steel is one of the basic construction materials the primary focus is exerted on the heavy industry. A phase transformation occurring during tempering of steels depends not only on the carbon content in the martensite and in retained austenite, but also on the content of various alloying elements. Tempering reduces the hardness, residual stress, but increases the ductility. The reduction of hardness is the inevitable consequence of improved strength. The structural changes that occur during the tempering of steels depend on the temperature, time of the process and the concentration of carbon. During tempering of steels, occurred two unfavorable effects of decrease the impact strength. The first in the temperature range of 200÷350°C (referred to as irreversible temper brittleness) and the second in the range of 450÷600°C (called the reversible temper brittleness). Both of the effects continue to inspire many researchers. The aim of this study is to explain influence of the kinetics of phase transformations during tempering on the fracture toughness of model steel with different carbon content. Optimum mechanical properties are achieved by proper design and careful implementation of heat treatment technology. Above all, it is necessary to avoid the temperature range 250÷400°C, in which the temper brittleness occurs. Decrease in fracture toughness of steel tempered at this temperature range may be due to the destabilization of retained austenite [1÷5]. Also, due to the non-uniform dissolution of martensite (preferential along the primary austenite grain boundaries) [6, 7], or by growth of cementite precipitations, which formed easy way of cracking [8÷15]. Another theory explains the temper brittleness by the cementite nucleation mechanism during the tempering [16÷19]. After the dissolution of metastable ε carbide the carbon redistribution leads to its strong local enrichment in the matrix, resulting in increasing stress and, consequently, reducing the ductility. To expand the knowledge of the carbon effect on mechanical properties (hardness, fracture toughness) in this study the tempering temperature impact on the selected properties of the Cr-Mn-Mo model steels was studied. |
| File Format | PDF HTM / HTML |
| Volume Number | 34 |
| Alternate Webpage(s) | https://imat.polsl.pl/Archiwum/2013/3/2013-3-6-full%20text.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
