Wear-resistant plate is a typical high-quality low-alloy high-strength wear-resistant steel. It is a key material for manufacturing wear-resistant machinery such as crushers, scrapers, and shield machines. There have been a large number of literature reports on the research on wear-resistant plates. These studies mainly focus on the aspects of structural phase transformation, fatigue fracture performance and hydrogen embrittlement in steel. However, there are few reports on its thermal deformation behavior. To this end, scientific and technical personnel used a thermal simulation testing machine to conduct a high-temperature axial single-pass compression deformation test on the wear-resistant plate, systematically studied its thermal deformation behavior, and analyzed the microstructure of the wear-resistant plate after deformation. It provides technical guidance and theoretical basis for the formulation and optimization of its thermal processing technology.
The chemical composition (mass fraction/%) of the JFE-C400 wear-resistant plate used for the test is 0.41C, 0.78Mn, 0.25Si, 0.0006P, 0.001S, 0.85Cr, 1.80Ni, 0.25Mo, 0.0006O, 0.0010N. A cylindrical compression specimen of Φ8 mm × 15 mm was cut and processed from the wear-resistant plate, and then a high-temperature axial single-pass compression test was conducted on the Gleeble-3800 thermal simulation testing machine. The sample was first heated to 1423K at a heating rate of 10K·s-1, kept for 5 min, and then cooled to different deformation temperatures (1123, 1223, 1323, 1423K) at a cooling rate of 10K·s-1, and then compressed after being kept warm for 5s. Deformation; the strain rates are 0.01, 0.1, 1, and 10s-1 respectively, and the maximum true strain is 0.9. Water is sprayed and cooled immediately after deformation to preserve the grain boundaries after high-temperature deformation. Use a wire cutting machine to cut the hot compression sample from the middle along the compression direction. After grinding and polishing, use a mixed solution of saturated picric acid + a small amount of seagull lotion to etch to reveal the austenite grain boundaries. Use a LEICA MEF4M optical microscope. Observe its microstructure. The results show:
(1) The flow stress and peak strain of the wear-resistant plate decrease as the deformation temperature increases and the strain rate decreases;
(2) Under the conditions of a true strain of 0.9 and a strain rate of 0.01 to 10s-1, as the strain rate increases, the temperature at which complete dynamic recrystallization occurs also gradually increases;
(3) Complete dynamic recrystallization of the wear-resistant plate will occur only when the strain rate is 10s-1 and the deformation temperature is higher than 1323K;
(4) The thermal deformation activation energy of the wear-resistant plate is calculated to be 333.726kJ·mol-1, and the quantitative relationship between the peak strain and the Zener-Hollomon factor and the high-temperature plastic deformation constitutive equation of the steel under dynamic recrystallization conditions are established.
High temperature plastic deformation characteristics of wear-resistant plates
Wear-resistant plate is a typical high-quality low-alloy high-strength wear-resistant steel. It is a key material for manufacturing wear-resistant machinery such as crushers, scrapers, and shield machines. There have been a large number of literature reports on the research on wear-resistant plates. These studies mainly focus on the aspects of structural phase transformation, fatigue fracture performance and hydrogen embrittlement in steel. However, there are few reports on its thermal deformation behavior. To this end, scientific and technical personnel used a thermal simulation testing machine to conduct a high-temperature axial single-pass compression deformation test on the wear-resistant plate, systematically studied its thermal deformation behavior, and analyzed the microstructure of the wear-resistant plate after deformation. It provides technical guidance and theoretical basis for the formulation and optimization of its thermal processing technology.
The chemical composition (mass fraction/%) of the JFE-C400 wear-resistant plate used for the test is 0.41C, 0.78Mn, 0.25Si, 0.0006P, 0.001S, 0.85Cr, 1.80Ni, 0.25Mo, 0.0006O, 0.0010N. A cylindrical compression specimen of Φ8 mm × 15 mm was cut and processed from the wear-resistant plate, and then a high-temperature axial single-pass compression test was conducted on the Gleeble-3800 thermal simulation testing machine. The sample was first heated to 1423K at a heating rate of 10K·s-1, kept for 5 min, and then cooled to different deformation temperatures (1123, 1223, 1323, 1423K) at a cooling rate of 10K·s-1, and then compressed after being kept warm for 5s. Deformation; the strain rates are 0.01, 0.1, 1, and 10s-1 respectively, and the maximum true strain is 0.9. Water is sprayed and cooled immediately after deformation to preserve the grain boundaries after high-temperature deformation. Use a wire cutting machine to cut the hot compression sample from the middle along the compression direction. After grinding and polishing, use a mixed solution of saturated picric acid + a small amount of seagull lotion to etch to reveal the austenite grain boundaries. Use a LEICA MEF4M optical microscope. Observe its microstructure. The results show:
(1) The flow stress and peak strain of the wear-resistant plate decrease as the deformation temperature increases and the strain rate decreases;
(2) Under the conditions of a true strain of 0.9 and a strain rate of 0.01 to 10s-1, as the strain rate increases, the temperature at which complete dynamic recrystallization occurs also gradually increases;
(3) Complete dynamic recrystallization of the wear-resistant plate will occur only when the strain rate is 10s-1 and the deformation temperature is higher than 1323K;
(4) The thermal deformation activation energy of the wear-resistant plate is calculated to be 333.726kJ·mol-1, and the quantitative relationship between the peak strain and the Zener-Hollomon factor and the high-temperature plastic deformation constitutive equation of the steel under dynamic recrystallization conditions are established.
