Precipitation Mechanism and Reduction of Amount of Primary Carbides During Electroslag Remelting of 8Cr13MoV Stainless S
- PDF / 4,756,851 Bytes
- 13 Pages / 593.972 x 792 pts Page_size
- 73 Downloads / 181 Views
OV martensitic stainless steel is used mainly in high-grade kitchen knives because of its high hardness, wear resistance, and stainless properties. The high hardness and wear resistance of 8Cr13MoV steel can be achieved by solution strengthening of carbon and precipitation strengthening of secondary carbides, and good corrosion resistance can be achieved by using a high-chromium content. However, many primary carbides precipitate during the solidification of liquid steel because of high carbon and chromium contents. Primary carbides are large and irregular in their morphology and have a high hardness, which is detrimental to the fracture toughness of tool steel.[1] Primary carbides tend to reduce the ductility and toughness of tool steel,[2,3] and are harmful in the cold rolling of 8Cr13MoV steel. The formation of primary carbides consumes a large amount of carbon and chromium in
QIN-TIAN ZHU, JING LI, JIE ZHANG, and CHENG-BIN SHI are with the State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing (USTB), Beijing 100083, China. Contact e-mails: [email protected] and [email protected] JI-HUI LI and JUN HUANG are with the Yangjiang Shi Ba Zi Limited Company, Yangjiang 529500, China. Manuscript submitted May 15, 2018. Article published online April 15, 2019. METALLURGICAL AND MATERIALS TRANSACTIONS B
the steel matrix,[4] which results in a reduction in hardness, wear resistance, and corrosion resistance of the steel. The knife-edge thickness is several dozens of microns and primary carbides are usually micron-sized. If primary carbides are removed from the knife edge during use, the sharpness will deteriorate rapidly. Therefore, a reduction of the amount of primary carbides in 8Cr13MoV steel is significant for improving the performance of knives. Many efforts have been devoted to reduce and refine primary carbides in high-carbon steel, high-chromium white cast iron, and superalloy. Some alloying methods have been used to refine primary carbides, such as Ti addition.[5–8] The refinement of primary carbides has been correlated with the emergence of TiC particles, which can act as primary-carbide nuclei. However, primary TiC particles are likely to generate cracks during rolling, which is not applicable for 8Cr13MoV steel. Heat treatment is also used to reduce and refine primary carbides, which can lead to fragmentation or decomposition of primary carbides.[9–13] However, the authors’ previous study showed that heat treatment (1473 K for 2 hours) had only a slight effect on the size and morphology of blocky primary carbides.[4] In 8Cr13MoV steel, primary carbides are generated during the solidification process of the steel. ESR helps to control element segregation and reduce the amount of primary carbides.[14] The precipitation of primary carbides is related closely to alloying element segregation, VOLUME 50B, JUNE 2019—1365
which is affected mainly by the ESR-processing parameters, such as melting rate, cooling rate, and fill ratio.[15–17] The melting rate is the most important paramete
Data Loading...
