The Hole Defect Analysis Of Engine Crankshaft Casting

Crankshaft is one of the most important parts of automobile gasoline engine,mainly by the casting method for casting blank, then through machining. Crankshaftcasting should have high strength and abrasion resistance, fatigue resistance andimpact toughness, so its material is commonly nodular cast iron. The casting qualityrequirements is strict, do not allow the existence of casting defects, especially the holetype casting defects.This paper first introduces the importance of the engine assembly and crankshaftcasting crankshaft production process, in the following sections focus on castingsoften appear in the process of production of hole type casting defects.Crankshaft casting holes casting defects due to shrinkage cavity, porosity, slaginclusion, sand holes four categories.In this paper, with the considerable length is the second chapter to the fifthchapter respectively expounds four hole type casting defects formation mechanism,influencing factors and preventing methods, it has also reference gating system designprinciple, the principle of feeding, filter filtration principle, reaction principle, the hotmetal and molten iron alloy elements mould mechanism, etc., the causes of hole typecasting defects for further analysis and research, generalize the gating system and riser,molten iron alloy components, such as sand parameters affecting shrinkage cavity,porosity, slag inclusion, sand holes are the main factors. According to the principle ofhole defect influence factors and formation, emphatically introduces the adopted aseries of solutions. These methods in the emphasis on the trial application of newtechnology, such as changes in gating system design, riser design improvement, theapplication of the heating block, filter technology and application of new type thermalinsulation riser, through many times experiment or production, prove the feasibility ofthe new technology. And some method is through the analysis of characteristics ofhole defect, summed up in the long-term production data, such as molten iron alloyand reasonable process parameters of sand control, production process management,and other methods. The solution of the defect, besides from directproduction factors, should also be other comprehensive consideration of variousinfluencing factors. Only in a single factors take measures, defects cannot effect aradical cure, so the article for each hole defect solution, are a variety of methods, acomprehensive implementation so that the crankshaft to effectively control holedefect.Regardless of the process parameters, the control of production processimprovement, or the application of new technology, should be based on thecharacteristics of the casting itself, according to his way of casting production toadopt the suitable method, finally to make the engine to improve the quality of theproduct.