Structures for Heat Treatment Assembled from Cast Elements

Various types of technological equipment individually designed for operation in pit and elevator heat treatment furnaces aredescribed in this article. A common characteristic of these structures is that they are composed of several or several dozen thin--walled elements of various shapes and sizes, gravity cast in sand moulds from creep-resistant alloys (austenitic Cr-Ni/Ni-Crcast steel and cast nickel alloys). The design of the castings requires the development of a manufacturing technology that caneffectively use the principle of the simultaneous solidification of all components. Properly designed equipment should have minimumweight, maximum strength, and maximum loading capacity combined with adequate durability and reliability. Two designsof the equipment for the heat treatment of steel parts were presented. Both designs, as well as their individual components, weredescribed in detail and illustrated. The main task of the equipment is to form the charge in the furnace and transport this chargeboth inside and outside the furnace. The first design is the design of an equipment for the heat treatment of large ring-shapedparts. The second design is the design of an equipment, whose structure can be modified using various repeatable components. Asa result of these modifications, different variants of the equipment are obtained, allowing for the heat treatment of five differenttypes of the shafts characterized by different shapes and sizes. The study is of an application nature. It is addressed to engineeringand technical staff dealing with both the design and operation of heat treatment furnaces.

Ultrasonic Rheocasting for Refinement of Mg Alloys Reinforced with LPSO Phase

In this work, ultrasonic rheocasting was used to refine the microstructures of Mg alloys reinforced with long period stacking ordered (LPSO) phase. The semisolid slurries of Mg-Zn-Y and Mg-Ni-Y alloys were prepared by ultrasonic vibration (UV) and then formed by rheo-squeeze casting under high squeeze pressure (~ 400 MPa). The effects of UV and squeeze pressure on microstructure and mechanical properties of the Mg alloys were studied. The results reveal that UV and rheo-squeeze casting can significantly refine the LPSO structure and alpha-Mg matrix in Mg alloys, but they cannot change the phase compositions of the alloys or the type of LPSO phase. When the squeeze pressure is 400 MPa, the average thickness of LPSO phase is decreased, and the block LPSO structure is completed eliminated and uniformly distributed at the grain boundaries. Compared with the gravity cast alloys without UV, mechanical properties of the rheocast Mg alloys were enhanced and reached the maximums when the squeeze pressure was 400 MPa.