挖掘机工作臂高强度钢板的矫直理论与试验研究

Leveling Theory and Experiment Study on High Strength Steel Plate of Excavator Working Arm

挖掘机是一种在土石开挖等方面具有不可替代作用的重要工程设备,核心部件质量诊断、智能化及整机轻量化是其发展的三大主要方向。针对钢板平直度对挖掘机工作臂焊接质量存在重要影响的问题,在传统辊式矫直理论的基础上,依据三点弯曲理论、板材变形特点及分层理论建立板材矫直过程中的应力中性层偏移量计算模型,从理论上证明中性层偏移现象的存在以及它与反弯半径、板材厚度及材质的关系。通过室温拉伸试验得到高强钢板Q690的力学性能以此作为模型构建的参数基础;再结合弯曲试验研究矫直过程中性层偏移规律,得到中性层偏移值与反弯半径的变化关系。在本课题组多辊矫直机试验平台上对中性层偏移理论进行验证,结果表明考虑中性层偏移的Q690钢板平直度小于1 mm/m。

Excavator is important engineering equipment which can be not replaced in the digging stones and soil, the quality diagnosis of key components, intelligent and lightweight are its three development directions. The flatness of high strength steel plate has important influence on the welding quality of excavator working arm, on the basis of traditional multi-roll leveling theory, a stress neutral layer offset model is established based on three-point bending theory, steel plate deforming characteristic and layered theory in the plate leveling process. It proves the existence of the stress neutral layer offset and the relationship of the reverse bending radius, the material thickness and the metal deforming capacity in theory. The mechanical property of high strength steel plate （Q690） is obtained by room temperature tensile test. Combined with the bending test, the neutral layer offset regular is studied in the high strength steel leveling process. The relationship between neutral layers offset values and reverse bending radius is found, the neutral layer offset model is verified and the flatness of leveled Q690 plate is less than 1 mm/m by using multi-roll leveling machine.