20CrMnTi鋼熱軋棒材鐵素體-珠光體帶狀組織的控制

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Abstract：This paper studied the banded structure of 2OCrMnTi steel bar samples at different positions in the rolling line.In therough rollng section withsmallplastic deformationand high temperature，the banded structure is relatively light. In the final rolling section with large plastic deformation and low stop rolling temperature， the banded structure is relatively heavy.Based on the above results，the roling process was controlled through experiments with final rolling temperatures of 800°C ， 825°C ， 865°C ， 905°C 915°C ，and 945°C ， and cooling speeds of 0.53°C/s and 1.50°C/s to control the banded structure of 2OCrMnTi steel hot-rolled bars. The results show that when the final rolling temperature is and the cooling speed is controlled at 1.50°C/s ，the banded structure of 20CrMnTi steel hot-rolled bars can be controlled at ?2.0 grade. The formation mechanism of hot-rolled bar banding was analyzed，which was the result of the combined effects of metal plastic deformation during roling and the cooling phase transformation of austenite into ferite and pearlite. When the bar structure is in the austenite region during metal plastic deformation，it is beneficial to control the banding.When the temperature is <913°C ，austenite undergoes phase transformation to precipitate primary ferrite，folowed by plastic deformation， which is unfavorable for controlling the banding.The 2OCrMnTi steel bar samples were scanned using the EPMA-172O electronic probe device after hot rolling and annealing，and the results showed that annealing treatment can aggravate the steel banding，causing C，Mn，and Cr elements to accumulate along the metal extension direction.

Keywords：2OCrMnTi steel; hotrolled bar;banded structure;final rolling temperature; cooling rate

1序言

帶狀組織包括一次帶狀組織和二次帶狀組織，一次帶狀組織的產生受連鑄或模鑄工藝的影響較大；二次帶狀組織主要是金屬在延展變形和冷卻過程中，奧氏體組織轉變形成的鐵素體-珠光體交錯的帶狀組織，受金屬變形量、變形速率、奧氏體冷卻相變影響較大[1-4]。（剩余6216字）