冷却温度对难加工合金切屑形貌影响机理研究

Research on Mechanism of Effect of Cooling Temperature on Chip Morphology of Difficult-to-cut Alloys

针对FV520B沉淀硬化不锈钢和TC4钛合金两种典型的难加工合金,利用自行研制的液氮射流冷却装置对不同切削速度和不同射流温度下两种材料的切屑微观形貌进行了试验分析。研究表明,在液氮射流冷却作用下,两种材料在切削时依然会产生绝热剪切现象,且随着切削速度的提高和射流温度的降低,切屑锯齿化程度、锯齿节距显著提高,绝热剪切带宽度、剪切带倾角略有降低,低温断屑情况相比常温得到明显改善。

FV520B precipitation-hardened stainless steel and TC4 titanium alloy are two typical difficult-to-cut alloys,and the chip formation mechanism of the two materials under different cutting speeds and jet temperatures is analyzed by using the liquid nitrogen jet cooling device developed by ourselves.Studies have shown that under the effect of liquid nitrogen jet cooling,the chips of the two materials still generate adiabatic shear,and with the increasing of cutting speed and the reducing of the fluid temperature,serrated chip degree and serrated pitch increased significantly,adiabatic shear band width and angle of shear band is reduced in different degree,low temperature chip breaker condition dramatically improved contrast with the normal temperature condition.