为研究锻造过程中脆性夹杂边物周围区域的应力场对其边界裂纹形成的影响，给出了平均应力度的定义及计算解析式，以平均球应力度为判据，研究了应力场对脆性夹杂物边界裂纹的影响规律．数值模拟结果表明：脆性夹杂物边界裂纹对平均球应力度的相关度高，将其作为一个参数来表征应力场对脆性夹杂物边界裂纹形成的影响规律是可行的；随平均球应力度代数值的减小，脆性夹杂物边界裂纹的尺寸减小，当平均球应力度代数值小于－2．3时，脆性夹杂物边界无裂纹形成．在Gleeble－3180热模拟试验机上，利用专门的试件和型砧进行了1220℃热压缩变形试验，通过扫描电镜观察了试件内部脆性夹杂物边界裂纹的形成规律，试验结果与数值模拟结果吻合．
In hot forging process, the stress field around a brittle inclusion is one of the most important factors for crack formation. To study the stress field′s influence on crack initiation, the definition of Average Relative Spherical Stress (ARSS) and its mathematical expression are proposed. Taking the ARSS as criterion, the influence of stress field on crack initiation was investigated, and numerical simulations were carried out. Results show that ARSS is highly relevant to the crack initiation between brittle inclusion and matrix metal. As the algebraic value of the ARSS decreases, the size of the existing crack reduces as well. When the algebraic value of the ARSS is smaller than -2. 3, there are no cracks found. Hot compression tests at 1 220 ℃ with dedicated specimens and anvils were conducted on a Gleeble-3180 thermo?mechanical simulator. After tests, a scanning electron microscope ( SEM) was employed to observe the crack forming inside the specimens and the simulation results agree well with the observed results.
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