Scholarlink

<p>Laboratory simulations on a Gleeble 3800 thermomechanical simulator were carried out for low-carbon shipbuilding steel of grade EZ35 to develop technological solutions for thermal and Thermo-Mechanical Control Process (TMCP) that produce a fine, homogeneous ferrite–pearlite microstructure with a ferrite grain size uniform across the plate thickness by hot working alone, without subsequent heat treatment. After austenitizing at 1150 °C, none of the TMCP schedules tested produced a homogeneous fine-grained microstructure. In contrast, austenitizing at 900 °C followed by hot working in the fully austenitic temperature ranges 890–820, 880–810, and 870–800 °C and final cooling at 1 °C/sec resulted in a ferrite–pearlite microstructure with a uniform ferrite grain size; the grain size decreased as the deformation temperature range was shifted to lower temperatures. Lowering the deformation finishing temperature to 790 °C and below led to abnormal ferrite grain growth and the appearance of coarse ferrite grains with tortuous boundaries in the final microstructure at a low post-deformation cooling rate of 1 °C/sec. It was established that increasing the post-deformation cooling rate from 1 to 5 °C/sec suppresses abnormal ferrite grain growth and ensures a homogeneous fine-grained microstructure when TMCP schedules with austenitizing at 900 °C are used and deformation is completed in the two-phase (<i>γ</i>+<i>α</i>) region. The results also show that, in low-carbon low-alloy steel EZ35, the recrystallization of hot-worked ferrite during intercritical deformation is significantly retarded at temperatures below 750 °C. Based on these findings, a new two-stage TMCP schedule is proposed that produces in EZ35 steel a homogeneous fine ferrite–pearlite microstructure with required strength and high density of high-angle grain boundaries in the ferrite.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Thermo-Mechanical Control Process of EZ35 shipbuilding steel for low-temperature marine applications

  • 期刊论文

  • 发表日期：

    2026年2月1日

查看全文
  • Artem G. Kravchenko,
  • Oleg A. Bagmet,
  • Leonid I. Efron,
  • Dmitry S. Astafiev

摘要

Laboratory simulations on a Gleeble 3800 thermomechanical simulator were carried out for low-carbon shipbuilding steel of grade EZ35 to develop technological solutions for thermal and Thermo-Mechanical Control Process (TMCP) that produce a fine, homogeneous ferrite–pearlite microstructure with a ferrite grain size uniform across the plate thickness by hot working alone, without subsequent heat treatment. After austenitizing at 1150 °C, none of the TMCP schedules tested produced a homogeneous fine-grained microstructure. In contrast, austenitizing at 900 °C followed by hot working in the fully austenitic temperature ranges 890–820, 880–810, and 870–800 °C and final cooling at 1 °C/sec resulted in a ferrite–pearlite microstructure with a uniform ferrite grain size; the grain size decreased as the deformation temperature range was shifted to lower temperatures. Lowering the deformation finishing temperature to 790 °C and below led to abnormal ferrite grain growth and the appearance of coarse ferrite grains with tortuous boundaries in the final microstructure at a low post-deformation cooling rate of 1 °C/sec. It was established that increasing the post-deformation cooling rate from 1 to 5 °C/sec suppresses abnormal ferrite grain growth and ensures a homogeneous fine-grained microstructure when TMCP schedules with austenitizing at 900 °C are used and deformation is completed in the two-phase (γ+α) region. The results also show that, in low-carbon low-alloy steel EZ35, the recrystallization of hot-worked ferrite during intercritical deformation is significantly retarded at temperatures below 750 °C. Based on these findings, a new two-stage TMCP schedule is proposed that produces in EZ35 steel a homogeneous fine ferrite–pearlite microstructure with required strength and high density of high-angle grain boundaries in the ferrite.