In this article, the forging manufacturer tongxin precision forging will tell you about some problems that often appear in the process of forging parts. You can refer to the causes of the problems, and avoid these problems in processing:
I. Aluminum oxide film:
The oxide film of the aluminum alloy is usually located on the web of the die forging, near the parting surface. The surface of the fracture has two characteristics: one is flat plate, the color varies from silver gray, light yellow to brown, dark brown; Second, the spots are small, dense and shiny.
The oxide film of aluminum alloy is formed when the exposed molten surface interacts with water vapor or other metal oxides in the air during melting and forging. It is formed in the liquid metal involved in the casting process. The oxide film in forging and die forging has no significant effect on the longitudinal mechanical properties.
Two, carbide segregation:
According to the forging plant analysis, carbide segregation usually occurs in the alloy steel with high carbon content, which is characterized by a large accumulation of local carbides, mainly because the Letenite eutectic carbides and secondary reticulate carbides in the steel are not broken and distributed uniformly during the open forging process. The segregation of carbide will reduce the forging deformation ability of steel, and lead to the forging parts cracking, heat treatment and quenching in the process of fire. The forging parts are easy to overheat and quenching, and the blade is easy to crack when the tool is used.
Three, bright line:
Bright line refers to the thin line with reflection ability and crystal brightness on the longitudinal fracture in the forging process, most of which are distributed on the entire fracture and most of which appear on the shaft.
Bright lines are mainly caused by alloy segregation. The slight bright line has little effect on the mechanical properties of the material. The serious bright line will reduce the plasticity and toughness of the material.
Four, non-metallic inclusions:
Nonmetallic inclusions are mainly formed during molten steel melting or casting cooling. They are formed by chemical reactions between components or between metals and the furnace gas and container. In addition, the forge advised that during the process of metal smelting and forging, refractory material falling into the molten steel will also form inclusions, known as slag inclusion. On the cross section of the forging, the nonmetallic inclusions may be distributed as dots, sheets, chains or blocks. Serious inclusions are easy to crack the forgings or reduce the service performance of the materials.
this is ball neck forgings produced by tongxin precision forging