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陕西渭南彩钢卷生产受力与变形研究​

陕西渭南彩钢卷生产受力与变形研究

过去,陕西渭南彩钢卷取过程中的内应力计算是以钢卷为弹性厚壁圆筒或弹性组合圆筒的计算为基础的。事实上,彩钢线圈的厚度普遍较大,而且彩钢线圈沿圆周具有明显的非圆特性。按圆曲线处理彩钢卷,计算误差较大。

因此,陕西渭南彩钢卷在卷取过程中,随着带钢厚度的增加,带钢在卷取过程中沿周向的非圆特性更加明显。然而,以往采用的封闭圆柱模型不仅偏离了带材的实际状态,而且不能准确预测层间滑移。根据热轧卷取工艺的设备和工艺特点,采用螺旋开口圆筒模型,提出了一套适用于热轧彩钢卷取的钢卷内应力分布模型,考虑到卷取过程中沿周向应力和变形的不均匀性以及盘头线圈与卷筒不完全接触的特点,并给出了相应的层间滑移判断条件,开发了相应的钢卷内应力和层间滑移预测软件,并应用于生产实践。
在卷取过程中,随着卷径的增大,某一层彩钢卷的径向压力增大;对于内层彩钢卷,即头部增大特别大,会增加层间粘连的概率;而对于卸卷,径向压力由内而外逐层降低,由于周向应力规律不同,最小值通常出现在线圈内部的某一层,线圈头部的环向应力随压力的增加而减小,陕西渭南彩钢卷线圈中间的一些层则降至最大。如果初始卷取张力较大,则可能出现负值。
对于软、薄彩钢卷,当彩钢卷的张力小于初始设定值且没有箍圈时,卷内径向应力过小,容易引起层间滑移,造成卷塌;虽然可以用较大的张力来避免卷塌,彩钢盘头卷取张力过大,导致前几个盘头的切向压应力过大,钢卷在吊装或放置过程中受到冲击扰动时,常产生心形缺陷;
鉴于目前采用锥形控制的硬核卷取技术,当从卷筒上取下线圈时,线圈内层向内收缩,当张力-锥度曲线的下降斜率过大时,抽芯很可能是由于磁芯处的拉应力过大所致。

In the past, the calculation of the internal stress in the coiling process of color steel coil was based on the calculation of the steel coil as an elastic thick wall cylinder or an elastic combined cylinder. In fact, the thickness of color steel coil is generally large, and color steel coil has obvious non-circular characteristics along the circumference. If color steel coil is treated according to circular curve, the calculation error will be large.

Therefore, in the process of coiling, with the increase of the thickness of the strip, the non-circular characteristics of the strip inside the coil are more obvious along the circumferential direction. However, the closed cylinder model used in the past not only deviates from the actual state of the strip, but also can not accurately predict the interlayer slip. Based on the equipment and process characteristics of hot rolling coiling process, a set of internal stress distribution model of steel coil suitable for hot rolling color steel coiling is proposed by adopting spiral opening cylinder model, considering the nonuniformity of stress and deformation along circumferential direction during coiling process and the feature of incomplete contact between coil head coil and drum, and corresponding judgment conditions of interlayer slip are given The corresponding prediction software of internal stress and interlayer slip of steel coil is developed and applied to production practice.
In the process of coiling, with the increase of coil diameter, the radial pressure of a certain layer of color steel coil increases; for the inner layer of color steel coil, that is, the increase of the head is particularly large, which will increase the probability of adhesion between layers; but for the coil unloading, the radial pressure decreases from inside to outside layer by layer; for the circumferential stress law is different, The minimum value usually occurs in a certain layer inside the coil, the hoop stress at the head of the coil decreases with the increase of its pressure, and some layers in the middle of the coil decrease to the maximum. If the initial coiling tension is large, negative value may appear.
For the soft and thin color steel coil, when the tension of color steel coil is less than the initial set value and there is no hoop, the radial stress inside the coil is too small, which is easy to cause the slip between layers and cause the collapse of the coil; although the large tension can be used to avoid the collapse of the coil, for the head of color steel coil, the coiling tension is too large, which causes the tangential compressive stress of the first few coils to be too large, When the steel coil is disturbed by impact during lifting or placing, it often produces heart-shaped defects;
In view of the current hard core coiling technology with cone control, when the coil is removed from the drum, the inner layer of the coil shrinks inward, and when the decline slope of the tension taper curve is too large, the core pulling is likely to be caused by too large tensile stress at the core.
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