Abstract：During the production of Ø75 mm GCr15 hot-rolled round steel in Xining Special Steel's high-quality small bar line, it was found that there was a center porosity defect in the bar after rolling, which resulted in a low pass rate of ultrasonic detection after the bar was finished. This study verified the optimized pass pattern by modifying the parameters of the round pass, combined with numerical simulation to study the changes in the stress and effective strain of the test bar core, and then verified by on-site production, and combined with the analysis of the qualified rate of ultrasonic detection of the finished bar to determine the appropriate process parameters and guide on-site production practices and improve the product quality level of bearing steel bars. In determining the parameters, the main measures were to increase the reduction of the second pass from 58 to 86 mm, and reduce the fourth pass from 58 to 30 mm. The optimized process directly produced Ø75 mm finished products from 11 pass, saving the energy consumption and roll wear consumption of the latter two rolling mills. The simulation results showed that the internal stress of the bar in the first pass changed from the previous tensile stress to the compressive stress, combined with the reduction of the rolling speed, which was beneficial to improve the quality of the bar core. The actual production proved that after the process optimization, the pass rate of ultrasonic detection was 96.37%, which was 3.63% higher than before.
王青海, 孙世平, 苟复钢, 金启邦, 年国恩, 车巨龙. Ø75 mm GCr15圆棒材孔型工艺优化及数值模拟[J]. 中国冶金, 2021, 31(8): 77-82.
WANG Qing-hai, SUN Shi-ping, GOU Fu-gang, JIN Qi-bang, NIAN Guo-en, CHE Ju-long. Process improvement and numerical simulation of Ø75 mm round bar pass design[J]. China Metallurgy, 2021, 31(8): 77-82.
BIAN S Y,ZHANG X,LI S L,et al. Numerical simulation, microstructure, properties of EH40 ultra-heavy plate under gradient temperature rolling-sciencedirect[J]. Materials Science and Engineering A,2020:791.
[9]
SI J Y,GAO F,HAN P B,et al. Simulation on extrusion process of TiAl alloy[J]. Intermetallics, 2011, 19(2):169.
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