Trial Production of Ductile Iron Castings Parts for Split Gearbox

The comparison of validation results of the three process schemes is shown in the table. Overall, Scheme III has certain advantages in actual production verification: high process yield, small number of sand cores, simple production operation of ductile iron castings, qualified casting at one time, and easier to ensure batch production quality.

Scheme NoProduction rate/%Sand iron ratio/%Cold iron utilization rate/%Verification mode of casting productionDifficulty of production operationNDT, processing verification
Scheme I53.36.76.93D printing sand core assembly castingComplexThe third batch is qualified
Scheme II71.68.426.9Not put into production verificationComplexโ€”
Scheme III69.66.420.23D printing sand core assembly castingSimpleFirst pass

The NDT results of ductile iron castings produced according to Scheme III show that the key areas of ductile iron castings reach UT0~1, RT0~3, and the other areas reach UT1, RT0~3, which meet the NDT requirements of such ductile iron castings. Solid metallographic and hardness testing shall be carried out at four corners of the box joint surface (wall thickness 25 mm), and the testing position is shown in Figure 1.

The inspection results show that the number of graphite spheres is 160~320/mm (conducive to the formation of carbon into graphite), and the joint surface is ferrite matrix structure (as shown in Figure 2); The solid hardness of ductile iron castings meets the requirements of 130~210 HB, and the mechanical properties fully meet the performance requirements of EN-GJS-400-15.