压力机床身铸造工艺设计

Casting Method Design of Pressing Machine Bed

介绍了J75G-800型高速精密压力机床身铸件的铸造工艺。由于铸件外形尺寸庞大而壁薄、内腔结构复杂,采取了如下工艺措施:(1)分型面与浇注位置一致;(2)增加工艺补正量,将最薄壁厚20mm增加到25mm,原主要壁厚25mm增加到30mm;(3)采用φ50mm×8mm无缝钢管作为4个贯穿床身全长的狭长内腔砂芯的芯骨;(4)为加快导轨的凝固速度,在导轨表面等距离设置40mm厚的石墨冷铁。铸件检测结果:组织致密,珠光体体积分数大于98%,导轨硬度平均值为190HB,各项力学性能均达到了设计要求。

The casting method of the bed casting of the J75G-800 model high speed precious pressing machine was introduced. Since the casting has large external dimensions and thin wall thickness, as well complicated internal cavities, therefore, the following method measures were adopted： （1）parting line was compatible with the pouring position; （2）adopting moulding allowance to increase the thinnest wall thickness from 20 mm to 25 mm, and the dominating wall thickness from 25 mm to 30 mm respectively; （3）using φ50 mm×8 mm seamless steel pipes as the core irons for making the cores forming 4 thin and long internal cavities; （4）setting graphite chills with thickness of 50mm on the surfaces of guides equidistantly in order to accelerate solidifying rate of the guides. The test results of the casting showed that the structure was dense, the volume fraction of the pearlite was more than 98%, average hardness of the guides was of 190 HB, and every items of mechanical properties reached design-required specifications.