共查询到19条相似文献,搜索用时 140 毫秒
1.
2.
分析了SPHD热轧带钢轧制孔洞缺陷的宏观及微观特征,认为形成孔洞的原因是由于基板中存在聚集状夹杂缺陷导致基板不能连续变形所致;在原料板完全正常时,由于酸轧线与带钢接触辊将原料板割出小孔,在带钢过轧机时压薄延伸形成孔洞。针对上述问题提出了改进措施。 相似文献
3.
4.
采用SEM及EDS能谱仪等试验手段,对冷轧生产中出现的孔洞缺陷及其成因和影响因素进行分析研究,针对不同类型的孔洞缺陷提出了相应的工艺改进措施。结果表明:产生孔洞缺陷的原因主要有夹杂类、异物压入、轧辊异常等类型,其中,以夹杂类为主,其特征为撕裂状韧窝状断口,或呈月牙形,在钢板的正反面尺寸差异不大,主要与炼钢工艺有关;异物压入类缺陷特征有明显的机械划痕或压痕,断口较光滑,正反面尺寸不等,主要与热轧工艺和冷连轧工艺有关;轧辊异常类缺陷特征为等距离周期性的孔洞,主要与轧辊磨损和老化有关。并针对不同类型的孔洞缺陷提出了相应的工艺改进措施。 相似文献
5.
6.
7.
通过扫描电镜和能谱仪对冷轧镀锌基板出现的孔洞缺陷进行了分析,结果表明孔洞处聚集的大量夹杂物是引起孔洞的原因,对冷轧原料的生产提出了改进建议。 相似文献
8.
9.
对热轧板孔洞缺陷形成的原因进行了分析,指出连铸过程操作参数控制不合理是产生该种缺陷的主要因素;利用水模试验研究了水口插入深度、拉速、吹氩量等因素对结晶器内气泡分布的影响,在此基础上提出了治理热轧板孔洞缺陷的措施,取得了较好的效果. 相似文献
10.
11.
M. G. Zelin H. S. Yang R. Z. Valiev A. K. Mukherjee 《Metallurgical and Materials Transactions A》1993,24(2):417-424
Cavitation in superplastically formed AA7475 aluminum alloy by gas pressure has been investigated. Two systems of cavity stringers
on the diametrical section of the pressure-formed domes were observed by using optical microscopy under normal light, polarized
light, and dark field. Qualitative analyses have shown that the cavity stringers are oriented 35 ∼ 60 deg to the midplane
of the sheet, and the spacing of the cavity stringers decreases with increasing strain. The explanation of this new observation
of cavity morphology is given from a viewpoint of cooperative grain boundary sliding (CGBS).
Formerly Associate Professor with the Department of Materials Science, Ufa Aviation Institute 相似文献
12.
13.
14.
15.
风口回旋区是高炉内产生还原气体及热量的主要区域,颗粒相和气相在风口回旋区内的相互作用非常剧烈。回旋区的形状和大小决定了炉内煤气流的一次分布,是炉况顺行的基础。本文为了从颗粒尺度来描述回旋区内部气体和颗粒的运动行为,建立和发展了离散单元法和流体计算力学耦合模型。耦合模型考虑了多个相间力的作用(包括曳力、虚假质量力、升力和压力梯度力),得到了不同时刻风口前焦炭颗粒的分布图、体积分数云图、速度矢量图等。这些图表明在鼓风速度130 m/s时,风口前有颗粒被吹开,形成了明显的空腔,风口前及其附近区域的颗粒在做回旋运动,可以断定回旋区已经形成,且在6 s时风口回旋区达到稳定。 相似文献
16.
17.
喷射成形是一项先进的材料制备技术.本文介绍了一种用喷射成形工艺来制备高硅硅钢片的技术和方法.并从合金母液的制备、喷射成形过程、喷射沉积坯的轧制及退火工艺和相关问题的分析等方面进行了研究. 相似文献
18.
19.
Friction-stir welding (FSW) of 3-mm-thick plates of 6061 Al and LF6 Al was conducted and the materials’ flow patterns in the
weld nugget along three perpendicular planes were analyzed. The onion structure viewed on any cross section normal to the
travel direction is independent of weld position. The weld morphology was examined along its length by considering planes
of different depths parallel to the surface. These showed semicircle streaks whose shapes depended on the depth of the observation
plane. It is determined that the weld nugget is composed of a series of identical half ellipsoid regions. A tentative simplified
cavity model is presented to explain the mass flow pattern and formation of defects in the weld nugget. This model is based
on the assumption that only the metal between the pin surface and the last maximum circle created by the pin rotation is in
a plasticized state. From this model, it is shown that the location and size of the cavity formed during the rotation of the
pin changes cyclically and it is related to the position of the pin’s center. The holes or slots left in the weld nugget center
or near the advancing side are directly related to the size of the cavity. The welding parameters or weld pitch affects the
volume of the cavity, and consequently influence the weld defects. A large weld pitch will cause holes to be formed in the
weld nugget because of the large cavity. The flow patterns, which show that the plasticized material flows from both advancing
and retreating sides to the weld center behind the pin, can be easily explained with this cavity model. 相似文献