提高棒料下料断面质量途径探讨

Discussion about method of improving the bar cutting surface quality through raising the hard brittle of material

棒料剪切法下料是机械行业的主要下料方法,但在剪切时易出现断面倾斜、压塌、不平度等缺陷,如何降低这些缺陷尚需详细探讨。本文分析了棒料剪切过程中影响断面质量的几个重要因素,如材料自身性质、剪切温度、剪切速度、应力状态等。针对这些因素提出相应提高断面质量的方法,发现剪切断面质量好坏与被剪材质自身机械性能及微观组织有直接关联。蓝脆温度下料是利用钢的蓝脆效应剪切棒料,在蓝脆温度区间钢的脆性增加使材料趋向脆性断裂;高速剪切下料是利用材料自身韧性与剪切速度的关系,在最优剪切速度,一般为5m/s-7m/s时剪切下料以获得较好的断面质量;表面缺口应力集中下料方式是通过提前在棒料上预制V型槽使棒料因应力集中发生脆性断裂。上述方法均能获得较好的断面质量。

Several important factors which affects the bar cutting surface quality including the properties of material, cutting temperature, shear rate and stress state have been analyzed in the text. Aiming at the above factors, the corresponding methods of improving the cutting quality have been put forward. It is found out that the cutting surface quality is directly related to the micro-structure and mechanical properties of material; the blue brittle cutting is a way to cut metal bar by use of blue brittle effect and make the bar tend to brittle fracture by increasing the fragility of the metal materialunder particular temperature; the high speed cutting can obtain better cutting quality at the optimized speed of 5m/s-7m/s by use of the relation- ship between theductile of material and the cutting rate; the stress concentration cutting at the bar surface of the material is a way to pre-cut the V-shaped groove in the bar in order to make the bar fracture due to stress concentration. All the above methods can obtain better cutting surface quality.