北京科技大学学报
北京科技大學學報
북경과기대학학보
JOURNAL OF UNIVERSITY OF SCIENCE AND TECHNOLOGY BEIJING
2014年
1期
97-103
,共7页
轧制%界面%润滑%压下率%应力分析
軋製%界麵%潤滑%壓下率%應力分析
알제%계면%윤활%압하솔%응력분석
rolling%interfaces%lubrication%reduction%stress analysis
针对轧制过程非稳态及润滑特性,通过流体力学分析,建立稳态、非稳态轧制变形区油膜厚度分布模型,提出油膜波动系数以研究油膜厚度的绝对波动,应用卡尔曼微分方程分析了稳态、非稳态轧制界面应力分布,并以稳态应力分布为基础提出应力波动系数以研究变形区应力的绝对波动.结果表明:稳态下压下率增加,轧制界面油膜变薄,压应力、切应力均增加;非稳态下随着入口板带厚度等扰动因素的波动加剧,油膜波动系数变大,绝对波动加剧;不同时刻非稳态压应力波峰的位置和数值都会发生变化;相比于切应力,油膜波动对压应力的影响比较大,当油膜厚度发生6.33%的绝对波动时,压应力和切应力分别产生1.17%和0.24%的绝对波动.
針對軋製過程非穩態及潤滑特性,通過流體力學分析,建立穩態、非穩態軋製變形區油膜厚度分佈模型,提齣油膜波動繫數以研究油膜厚度的絕對波動,應用卡爾曼微分方程分析瞭穩態、非穩態軋製界麵應力分佈,併以穩態應力分佈為基礎提齣應力波動繫數以研究變形區應力的絕對波動.結果錶明:穩態下壓下率增加,軋製界麵油膜變薄,壓應力、切應力均增加;非穩態下隨著入口闆帶厚度等擾動因素的波動加劇,油膜波動繫數變大,絕對波動加劇;不同時刻非穩態壓應力波峰的位置和數值都會髮生變化;相比于切應力,油膜波動對壓應力的影響比較大,噹油膜厚度髮生6.33%的絕對波動時,壓應力和切應力分彆產生1.17%和0.24%的絕對波動.
침대알제과정비은태급윤활특성,통과류체역학분석,건립은태、비은태알제변형구유막후도분포모형,제출유막파동계수이연구유막후도적절대파동,응용잡이만미분방정분석료은태、비은태알제계면응력분포,병이은태응력분포위기출제출응력파동계수이연구변형구응력적절대파동.결과표명:은태하압하솔증가,알제계면유막변박,압응력、절응력균증가;비은태하수착입구판대후도등우동인소적파동가극,유막파동계수변대,절대파동가극;불동시각비은태압응력파봉적위치화수치도회발생변화;상비우절응력,유막파동대압응력적영향비교대,당유막후도발생6.33%적절대파동시,압응력화절응력분별산생1.17%화0.24%적절대파동.
Based on the lubricating and unsteady properties of rolling processes and hydrodynamic analysis, a film distribution model of the deformation zone which concerns the steady and unsteady conditions is set up and the film wave coefficient is proposed which is used to study the absolute fluctuation of unsteady film thickness. The von Karman equation is used to describe the stress distri-bution of rolling interfaces under the steady and unsteady conditions. According to the stress distribution under the steady condition, the stress wave coefficient is proposed which is used to study and describe the absolute fluctuation of unsteady stress. It is found that large reduction results in a thinner film thickness and a larger hydrodynamic pressure and shear stress in the deformation zone under the steady condition. Under the unsteady condition, as the fluctuation of disturbance factors such as inlet strip thickness intensifies, the film wave coefficient increases, indicating that the absolute fluctuation of film thickness gets larger. The position and value of the pres-sure stress peak change with time under the unsteady condition. The absolute fluctuation of unsteady film thickness has a greater impact on the hydrodynamic pressure than on the shear stress. When the absolute fluctuation of film thickness is 6.33%, the pressure stress and the shear stress have a 1.17% and a 0.24% absolute fluctuation, respectively.