冷却结构对连铸结晶器铜板应力分布的影响

Effect of cooling structure on stress distribution of continuous casting mold copper plates

建立板坯连铸结晶器三维有限元热弹塑性结构模型,计算铜板等效应力及冷却结构对其影响。研究表明,冷却结构和传热条件决定铜板热面特定力学行为规律,宽面和窄面热面中心线应力分布规律相似,冷却结构尺寸并不改变铜板横截面应力分布的趋势。铜板厚度每增加5 mm,结晶器上部应力仅增大5~7 MPa,而镍层区域变化明显,宽面和窄面最大增幅分别约为60 MPa和50 MPa;镍层每加厚1 mm,宽面和窄面镍层中上部应力提升约20 MPa,而窄面镍层下部应力下降较急剧;当水流量和水温差恒定时,水槽深度增加,热面中心线应力减小,每加深2 mm,结晶器上部下降不足5 MPa,而下部变化较大,最大量达20 MPa。

A three-dimensional finite-element thermal-stress model of slab continuous casting mold was conducted to predict the equivalent stress on copper plates and its change caused by cooling structure. The results show that special stress distribution of hot surface is mainly governed by the cooling structure and heat-transfer conditions in mold, the stress distributions of hot surface centricities at wide and narrow faces are similar, and the stress trend of cross-sections of copper plates does not change with the geometry of cooling structure. The stress at upper surface of mold only increases 5-7 MPa with the thickness of copper plate increasing 5 mm, and that in regions with nickel layers is obviously promoted to the maximums of 60 MPa and 50 MPa on wide and narrow faces, respectively. In the upper nickel layers, the stress increases approximately 20 MPa with the thickness increases of nickel layers by 1 ram, while represents rapid decline on narrow faces in lower nickel layers. The stress is depressed with the depth of cooling water slots with constant flow rate and temperature difference of cooling water, and changed less than 5 MPa with each deepening 2 mm in upper mold and maximum in lower mold can be up to 20 MPa. Also, a series of rational suggestions are proposed for optimizing cooling structure in order to reduce the abrupt stress and stress concentration.