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Increasing the Strength and Impact Toughness of Carbon Steel Using a Nanosized Eutectoid Resulting from Time-Controlled Quenching
- Source :
- Materials, Vol 17, Iss 15, p 3696 (2024)
- Publication Year :
- 2024
- Publisher :
- MDPI AG, 2024.
-
Abstract
- High-carbon steels are normally used as tool materials. The use of such steels for construction is limited due to their increased brittleness and poor weldability. However, it appears that high-carbon steels possess certain hidden reserves for enhanced plasticity and strength if properly heat-treated. An unconventional heat treatment was applied to carbon eutectoid steel (0.8 wt.% C) in order to increase its strength and impact toughness simultaneously. Samples for tensile and impact testing were held at 800 °C for different time ranges from 3 min to 9 min with subsequent cooling in oil. It was established that for each type of sample, an optimal holding time exists that is responsible for increased strength and high impact toughness. The hardness and microhardness levels of the surface and under-surface regions of the samples reached 390 HV after optimal heat treatment. An X-ray revealed a shift of the (211)α-peak to the lower 2-theta angles after heat treatment with the optimal holding time; this indicates an increase in carbon content in alpha solid solutions of approximately 0.12 wt.%. Thus, a nanostructured mixture of low-carbon martensite and thin cementite plates is formed in the under-surface region of carbon eutectoid steel after heat treatment, with a controlled holding time at the austenitizing temperature.
- Subjects :
- carbon tool steel
heat treatment
gradient nanostructure
low-carbon martensite
cementite
interlamellar spacing
Technology
Electrical engineering. Electronics. Nuclear engineering
TK1-9971
Engineering (General). Civil engineering (General)
TA1-2040
Microscopy
QH201-278.5
Descriptive and experimental mechanics
QC120-168.85
Subjects
Details
- Language :
- English
- ISSN :
- 19961944
- Volume :
- 17
- Issue :
- 15
- Database :
- Directory of Open Access Journals
- Journal :
- Materials
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.21391e9cf9b24363945db5306ca211ed
- Document Type :
- article
- Full Text :
- https://doi.org/10.3390/ma17153696