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oa Structural-Phase State of Austenitic 20GL Steel After Thermal Treatment by Normalising and High-Temperature Tempering
Recommendations for improving performance
- Source: Johnson Matthey Technology Review, Volume 69, Issue 2, Apr 2025, p. 283 - 298
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- 28 Feb 2024
- 05 Jul 2024
Abstract
The article presents the results of a study of the influence of normalising at 900°C and high-temperature tempering at 650°C on the microstructure and mechanical properties of cast steel 20GL. Heat treatment modes with and without high-temperature tempering were analysed taking into account the geometric dimensions of the specimens. The microstructure and structural-phase composition of cast steel specimens after heat treatment were studied using transmission and scanning electron microscopy (SEM) and X-ray diffraction analysis. Results showed that the selected mode ensures noticeable changes to ferrite-pearlite, homogeneous, fine-grained structure with grain size number 9 and 170 Brinell hardness number (HB). Mechanical tests for static tensile and impact strength resulted in selection of the optimal content of manganese in studied cast steel as 1.2 wt%. It has been established that the processes of final deoxidation have the greatest influence on the mechanical properties of steel determining the nature and character of non-metallic inclusions.