Improving in cold resistance of castings made of 20GL type steels

The analysis of the literature data on the steels used for the manufacture of castings operating at negative temperatures and the technology of their manufacture is carried out. The effect of chemical and phase compositions on the strength and impact strength characteristics is revealed. The rational technology for manufacturing of these castings is considered. Methods for obtaining of high impact strength of castings made of 20GL type steels at –40...–60 °C temperatures are given. Modification, microalloying and rational modes of heat treatment are used as methods of rational control of the steels structure. The heat treatment technology of castings, which provides the necessary package of properties and reliable operation, is proposed.

Excellent fluoride removal performance by electrospun La-Mn bimetal oxide nanofibers

La-Mn bimetal oxide nanofibers used as adsorbent for the defluoridation of water was synthesized by electrospinning - heat treatment technology. The La-Mn bimetal oxide nanofiber adsorbent with specific surface area...

Technological Features of the Manufacture of Disk Working Bodies of Tillage and Seeding Machines

The purpose of this study is to improve the technology of manufacturing spherical disk working bodies of tillage machines to increase their wear resistance and strength. The world's leading manufacturers achieve high wear resistance and strength of discs made of boron-containing steels both in their chemical composition and the choice of rational heat treatment technology. Experimental studies of 30MnB5 steel parts revealed that heating for 15 minutes to a temperature of 850°C and quenching in water was sufficient to achieve maximum hardness values. To prevent hardness reduction and to ensure the necessary elasticity and viscosity of the discs, it is recommended to temper at a temperature of 180°C and combine with heat before painting with powder paint. The application of cutting blanks with cutting of depressions along the outer contour of the disk and internal holes on the laser machine, as well as the formation of the finished shape of parts in the process of hot stamping and subsequent heat treatment in quenching dies. 1. The market of disk working bodies of tillage and sowing machines is studied, technological processes of manufacturing of which it is expedient to improve. 2. Theoretical and experimental study of the structure, structure and material properties of samples of spherical disks of imported agricultural machinery. The choice of 30MnB5 pine steel for their production is substantiated. 3. The improved technological process of manufacturing spherical disks is developed. It is recommended to form them by hot stamping in cold dies and intensive hardening in a water bath. 4. The project development of the section of production of disk working bodies of tillage and sowing equipment is carried out.