论文部分内容阅读
LY12和 LC4等可热处理强化铝合金室温塑性不好,冷挤时产品表面容易开裂,因此,适宜温热挤压成形。根据 LY12和 LC4在各种温度下的机械性能试验、温热复合挤压试验和产品机械性能试验,确定了合理的温挤温度范围。考虑到材料塑性和产品表面质量,温挤温度不应低于250～300℃。若产品有强度要求且挤压后不另进行热处理,则应高于400℃。当挤压温度超过400℃以后,由于合金固溶强化的作用加强,挤压压力下降趋势很小。随着挤压温度从室温升至300℃左右,产品室温强度性能只是略有下降或几乎不变,而当挤压温度超过300℃,产品强度性能反而开始上升,当挤压温度在400℃以上时,产品强度性能可以接近甚至超过其淬火时效状态的强度性能。这是因为在400℃以上挤压时,挤压后产品存在淬火时效效应,这点已被显微组织检查所证实。因此 LY12和 LC4采用温挤成形,不但可以保证产品表面质量,而且可能不另进行热处理而达到淬火时效状态的强度性能。
LY12 and LC4 and other heat-treatable aluminum alloy at room temperature poor plasticity, cold extrusion products easy to crack the surface, therefore, suitable for warm extrusion. According to LY12 and LC4 at various temperatures under the mechanical properties of the test, thermal composite extrusion test and mechanical properties of products to determine a reasonable temperature range of temperature extrusion. Taking into account the material plasticity and product surface quality, temperature extrusion temperature should not be lower than 250 ~ 300 ℃. If the product has the strength requirements and extrusion without further heat treatment, it should be higher than 400 ℃. When the extrusion temperature exceeds 400 ℃, due to the role of the alloy solid solution strengthening, squeeze pressure drop trend is small. With the extrusion temperature increased from room temperature to about 300 ℃, the strength performance of the product at room temperature only slightly decreased or almost unchanged, but when the extrusion temperature exceeds 300 ℃, product strength performance instead began to rise, when the extrusion temperature at 400 ℃ Or above, the strength performance of the product can be close to or even exceed the strength performance of its quench-aged state. This is because when extruded above 400 ° C, there is a quenching effect of the extruded product, which has been confirmed by microscopic examination. Therefore, LY12 and LC4 using warm extrusion forming, not only to ensure the quality of the product surface, and may not be further heat treatment to achieve the strength of the quenching aging state properties.