Process Optimization And Quality Control Of Full Chilled Low Alloy Casting Iron Camshaft

Thanks to its excellent performances, such as wear and scratch resistance andrelatively low cost, the fully chilled low alloy cast iron camshaft is broadlyapplied overseas in automobile manufacturing industry. But, at home, due to lackof mature technology and less experience, which can be referred to, the fullychilled low alloy cast iron camshaft is less applied. So studying the production.technology of fully chilled low alloy cast iron camshaft has theoretical and actualsignificance.Using technology experience and analysis method, this text looks for relevantfactors having influences on casting quality of the fully chilled low alloy castiron camshaft and determines production technology and process control methodof the fully chilled low alloy cast iron camshaft to reach batch productionrequirements of the fully chilled low alloy cast iron camshaft. First, analyze theconditions having influences on D type graphite formation of the fully chilledlow alloy cast iron camshaft, reduce and control the D type graphite formationthrough control of alloy elements, molten iron overheat duration, overheattemperature, pouring time and pouring speed, molten iron inoculating treatment,innoculant choice, chilled-iron dimensions etc.; next, proceed to a lot ofexperiences and analysis of machinability of the fully chilled low alloy cast ironcamshaft, and by control of alloy composition, pouring temperature and speed,inoculation treatment, overheat temperature and temperature holding time, casestructure, cast dimension accuracy, casting defects etc. improve and increase themachinability of the fully chilled low alloy cast iron camshaft; finally, proceed toexperiences and analysis of three ordinary defects of the fully chilled low alloycast iron camshaft and establish corresponding improving measures to lower thedefect occurrence.On the basis of study and analysis mentioned above, further optimization iscarried out to production, establish the important points of production technology of the fully chilled low alloy cast iron camshaft. 1) The CE is controlled between3.8%～4.2% 2) The S of molten iron is controlled between 0.04%～0.08% 3)The proportion between the furnace charge, pig iron and scrap steel is controlledto: 4 : 3 : 3 4) The microelements such as Ti and V are controlled below 0.03%5) The temperature holding time of molten iron is controlled between 1450～1500℃, the overheat temperature between 1500～1550℃, the overheat timebetween 10～20min 6) The pouring temperature is controlled between 1380～1420℃, the pouring time between 5～7s. Production shows that this technologycan satisfy the requirements of technical standard and batch production of themanufacturer.