20CrMnTi钢热轧棒材铁素体-珠光体带状组织的控制

打开文本图片集

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

带状组织包括一次带状组织和二次带状组织，一次带状组织的产生受连铸或模铸工艺的影响较大；二次带状组织主要是金属在延展变形和冷却过程中，奥氏体组织转变形成的铁素体-珠光体交错的带状组织，受金属变形量、变形速率、奥氏体冷却相变影响较大[1-4]。（剩余6216字）