Microscopic characteristics of banded structure in PCrNi3MoV high-strength steel in quenching and tempering

doi:10.13251/j.issn.0254-6051.2024.03.023

Abstract

Abstract: Alloying elements in PCrNi3MoV high-strength steel can improve the hardenability and mechanical properties, but also lead to banded structure by their segregation. Microscopic characteristics of banded structure in the PCrNi3MoV steel in different heat treatment processes were studied by means of optical microscope, scanning electron microscope, transmission electron microscope and electron probe microanalysis. The results show that the banded structure presents at different heat treatment stages of the tested steel, though the microscopic composition and characteristics are different. In the quenched state, the banded structure is characterized by alternating distribution of large and small size grains. In the tempered state, the size of martensitic lath in fine-grained region of the banded structure is smaller, the precipitation density of the carbides is higher, and the microhardness of the fine-grained region is higher than that in the coarse-grained region, which is attributed to the segregation of C and Cr, Mo, Mn and V elements in the fine-grained region, the grain strengthening and precipitation strengthening effects are more pronounced than those in the coarse-grained region.

Key words: Cr-Ni-Mo-V steel, banded structure, quenching and tempering treatment, element segregation

CLC Number:

Du Yunfei, Bai Rui, Wu Pu, Zhang Yaqin. Microscopic characteristics of banded structure in PCrNi3MoV high-strength steel in quenching and tempering[J]. Heat Treatment of Metals, 2024, 49(3): 135-140.

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