大变形量下高碳钢环件冷轧变形过程模拟与试验研究

Numerical Simulation and Experimental Investigations on Deformation Process in Cold Ring Rolling of High Carbon Steel during Large Deformations

研究了大变形量下高碳钢环件冷轧变形行为,利用有限元模拟方法分析了环件冷轧过程中的形变规律,采用光学显微镜、SEM等材料表征手段研究了大变形量下环件冷轧过程中的组织演化特点。结果表明:在较小的变形量下,环件内外侧应变较中间应变大,且变形首先发生在环件外侧;整个环件变形过程中,环件中间层的晶粒变形程度最小,外层次之,内层的变形最为剧烈;铁素体基体沿轧制方向呈现明显的方向性,碳化物颗粒分布更为均匀,且数量变少;随着变形量的增大,环件内层的应变明显大于外层的应变,且最小应变的位置偏移至靠外层比较近的区域,其组织中碳化物颗粒脱落加重;当变形量达到62.5%时,环件达到塑性极限,在内侧表面产生裂纹发生破坏。

The cold ring rolling process of high carbon steel during large deformations was investigated herein.The deformation behaviour of the cold ring rolling process was analyzed by the finite element simulation method.The instruments like optical microscope and scanning electron microscope were employed to characterize the microstructure evolution of the cold rolled rings under large deformations.Results indicate that under smaller deformations,both of the outer and the inner sides of the ring exhibites higher plastic strain than that on the middle part and deformation firstly occurres in the outer side.It is observed that the most severe deformations occurre in the inner surface of the ring,the less severe deformations in the outer surface and the least deformation in the middle part during the cold ring rolling process.With the deformation increasing,the inner side shows higher strain than that of the outer surface,and the location with the least strain shiftes to the peripheral layers.The ferrite matrix shows a clear direction along the rolling direction,and the distribution of cementite is more homogeneous with reduced carbide particles amount.Meanwhile,the shedding of the carbide particles is aggravated.When the deformations reach to 62.5%,the cold rolled ring reaches plastic limit with cracks firstly happening on the inner surface of the cold rolled ring.