The process parameters of lost foam casting have significant influence on the mechanical properties and the formation of carburizing defects. Through the simulation verification of the first two sections, it is found that the vertical casting scheme is easier to obtain the cast steel bearing products with less defects and better quality than the horizontal casting scheme. In addition, the other technological factors affecting the casting quality and riser feeding are pouring temperature, negative pressure, pattern density, coating strength and air permeability. In order to determine an optimal process plan, the orthogonal test method will be used to simulate the three main process parameters to achieve the purpose of process optimization.
The paint adopts mature commercial coatings, the brush coating process and drying process are consistent, and the default coating strength and air permeability are consistent. In this scheme, three factors orthogonal simulation experiments were carried out on pouring temperature, negative pressure degree and pattern density.
Orthogonal experimental design is a design method that uses orthogonal table to arrange and analyze multi factor experiments. Through the analysis of partial test results, we can understand the situation of comprehensive test and find out the optimal level combination. The basic procedure of orthogonal design is as follows:
a) Determine the purpose and requirements of the test
b) Selected factors and levels
c) Choose the right orthogonal table
d) Head design
e) Train test plan
f) Based on the analysis of the test results, the primary and secondary order of the factors is obtained, and the better combination is selected.
The purpose of orthogonal test is to optimize the process parameters and improve the process yield under the premise of ensuring the casting quality. Three factors including pouring temperature, negative pressure degree and pattern density were selected as the research objects. The higher the safe height was, the better the feeding effect was. At the same time, the more space to improve the process yield was.
