润滑液对内螺纹冷挤压成形质量的影响

Influence of lubricating fluid on forming quality of internal thread during cold extrusion

为了改善挤压工艺,提高螺纹成形质量,以316不锈钢为试验材料,采用试验方法研究了不同润滑液对挤压过程和挤压质量的影响规律。在4种不同的润滑剂条件下对内螺纹进行了挤压成形试验,获得了不同润滑剂下的挤压扭矩变化曲线和成形后螺纹的牙型状况,并对螺纹牙型显微硬度进行了测量。试验结果表明,螺纹在干挤压条件下扭矩较大,当转速为150 r·min^(-1)时,润滑后的扭矩较干挤压最大降低32.8%;当转速为200 r·min^(-1)时,扭矩最大降低30.3%;润滑条件下螺纹牙顶缺陷明显减少,牙型对称度提高,牙型显微硬度略有增加。

To improve the extrusion process and improve the forming quality of thread,taking 316 stainless steel as the test material,the test method was used to explore the effect laws of different lubricating fluids on the extrusion process and extrusion quality.Extrude forming tests of the internal thread were carried out under four kinds of lubricating fluid conditions.The variation curves of extrusion torque under different lubricating fluids and the teeth shapes of thread after forming were obtained.The microhardness of the teeth shapes of thread was measured.The test results show that the torque of thread is larger under dry extrusion condition.When the speed is 150 r·min^(-1),the torque of thread after lubrication is reduced by maximum of 32.8%compared with that of dry extrusion.When the speed is 200 r·min^(-1),the torque is reduced by maximum of 30.4%.Under the lubrication condition,the defect of thread tip is obviously reduced,the symmetry of teeth shapes is improved,and the microhardness of teeth shapes increases slightly.