The Inclusions Movement Track Analysis And The Influence On Service Performance Of Casting

Inclusion is one of the most common defects in casting process, due to the high temperature liquid metal in the air oxidation reaction in the process of the casting and the involvement of the external slag content, so it is difficult to get completely do not contain slag defects castings. Due to slag defects reduces the effective area of the metal substrate, and destroy the continuity of metallic matrix, which reduces the mechanical properties of casting material, in high cycle load under the micro cracks easily produced in slag position, and eventually developed into macroscopic crack and cause the parts lose efficacy, which seriously affects the service performance and fatigue life of castings. Moreover the slag defects which was in the casting internal, use general methods were difficult to accurate detection and measurement of their location and quantity, it also increased the difficulty of slag defect prevention. This paper is based on analysis of slag particles pouring position and movement locus in the casting filling process, and predict the service performance and fatigue life of the casting.The movement locus analysis of slag particles in casting filling process is the precondition of predict slag location, this paper is based on DPM dispersion particle model, turbulent flow model of liquid metal in the casting process and heat transfer model of solidification, studies on the effect of gating system, pouring time, pouring temperature on slag inclusion movement locus and stop position. Use the slag data information extraction technology and finite element grid mapping technology, obtained the slag defect information and establish the heterogeneous material casting model. Based on this, research the effect of the slag defect on serving performance and fatigue life of casting. It has great significance of casting design and pouring parameter optimization. Through the research in this paper, some results can be generalized as follows:(1) Based on dispersed particle motion model, established the slag particles moving along with the flow mathematical model, and track the slag inclusion movement locus during the filling and solidification process, provides foundation for the numerical simulation of casting slag defects research.(2) With different process conditions of the slag casting experiment, analyzes the distribution form of different location and the law of slag, the experimental results show that slag location and distribution characteristics with the simulation results was highly similarity, proves the reliability of the slag forecasting model.(3) Studies on the effect of casting technology on casting slag defects, the gating system structure, pouring time, grain density levels were carried out in three factors orthogonal analysis, concluded that influence order is gating system> pouring time> pouring temperature, and obtained the parameters of optimal combination to reduce casting slag rate. Provide the reference for optimize the casting process to reduce casting slag behavior.(4) Based on slag grains of data extraction technology and finite element grid mapping technology the heterogeneous material model was established, using VB6.0write program to extraction and mapping the slag information.By the commonly used non continuity mechanics model established including slag defects heterogeneous materials model. Provides a bridge for service performance analysis of the casting with slag defects.(5) Research on the effect of slag defects on the casting service performance, through the analysis service of performance propeller casting with slag defects, results show that the slag defects lead to stress concentration and increased the maximum stress value, makes the fatigue life values of the propeller decreased significantly. It has great significance to predict the service performance exactly of casting with slag defects.