Foundry
The results of investigations in the field, of structure formation and characteristics of castings, produced by means of continuously-cyclic casting by directional hardening of white high-chromium, grey, high-test cast irons and examples of their practical application are given.
The worked out mathematical model confirms the presence of non-symmetrical front edge of crystallization by cut of casting and allows to estimate qualitativly the dynamics of the casting shell growth in crystallizer in course of time.
The analysis of existing ways of production of the piston ring slugs is carried out. The advantages and disadvantages of the ways are examined. The way of the slugs production is offered
The theoretical concepts on crystallization of cast alloys on the basis of cluster mechanism of nucleation and growth of initial crystals are given, the technological methods of receiving of fine-grained structure of high-chromium hypercutectic cast irons are outlined.
The results of execution of the principal scheme of casting process of the piston ring slugs by means of dipping are presented.
The theoretical concepts on crystallization of cast alloys on the basis of cluster mechanism of nucleation and growth of initial crystals are given, the technological methods of receiving of fine-grained structure of high-chromium hypercutectic cast irons are outlined.
There are given the structure and characteristics of high-phosphorous cast irons and cast irons with ball-shape graphite in the article.
The expediency of insertion of 0,03-0,15 % titaniumA into high-manganese steel for increase of its crack- and wear-resistance, breakage of the structure at initial crystallization, elimination of column construction of castings and improvement of mechanical characteristics is proved. The new data on structure and composition non-metallic impurities are given, the alternative technology of modification is offered.
In this work, the segregation of solute elements in magnesium alloys AZ91D and AM60B in a crucible during hot-chamber die casting process has been investigated. The sampling of molten metal for chemical composition analysis was carried out at three positions within a crucible of 600 mm in depth. The picked molten metal was poured into a steel mold to cast into a rod 40mm diameter and 120mm length.
At casting of high-chromium cast iron in electroarc and high-frequency induction furnaces it is necessary to insert dead nickel-chromium catalyst with the purpose of alloying of nickel in the form of briquette, and at casting in induction furnaces of mains frequency in milled type between the pieces of metal-charging.
The influence of colloid-chemical state of ions of heavy metals on morphology and phase composition of their oxide modes (compound Al3+) is shown.
The analysis of efficiency and technological peculiarities of the ways of the electric power costs reduction at melting of cast iron and steel in electroarc and induction furnaces is presented. The most perspective for embedding in operating houses for conditions of RB is heating of burden due to natural gas in self-sufficient plants directly in loading bucket (baskets).
Metallurgy
The main ways of intensification of melting processes in the modern high-capacity electric arc furnaces of alternating current are examined, their advantages in the field of application are shown.
Some problems of the chip processing in modern arc steel-making furnaces are given.
The article is about the possibility of reapplication of the earlier used wire for binding of coils. The tests of the bindings samples were carried out, the results of which show that wire used for connection of coils is quite suitable for reapplication.
The possibilities of perfection of the processes of the metals continuous casting, including at the reconstruction of operating equipment without considerable capital costs, are shown.
The analysis of possibility of the fire cracks arising is carried out on the basis of existing data on changing of mechanical characteristics of industrial steel grades at high temperatures (in the processes of hardening and cooling in ingots and slugs). It is determined that at casting of slugs at MNLZ the failure of uniformity of hard skin in the initial period of its formation is possible.
The main indices of process of the ingots and slugs tilting in circular furnaces are examined and the mathematical model of metal heating which includes calculation of temperatures and thermal stresses in the cut of heated metal with the purpose of estimation of tilting influence on the temperatures and thermotensions dynamics is worked out.
The thermostressed state and conditions of crack propagation, the length of which determines the extent of deficiency of the bearing rollers metal, are investigated in this article.
This work is dedicated to investigation of peculiarity of cinder formation on rolled wire in the process of its cooling immediately after rolling, of the factors influencing on strippability of cinder at testing of the rolled wire samples after rolling and also after 20 and 50 days of storing outdoors.
It is shown that application of steels with mass proportion of carbon till 0,90% allowed to produce superhigh-strength wire with diameter 0,71 mm for arms of high pressure with ultimate stress limit 2800 MPa.
Science of materials
The investigation of heterogeneity of the boron-containing alloy structure with the aim of determination of the cooling speed influence on fragility is carried out in this work.
In the article there are examined the questions of optimization by means of mathematic modeling of the processes of blending and mixing of ceramic sialon powders, as particles sizes, their allocation and composition determine solidity and efficiency of ceramics.
In the article there are examined the questions of improvement of structure of the press mold coating of composition Ni-20%Co, produced by means of galvanic deposition. It is shown that application of thermocyclic processing allows to remove heterogeneity of structure on cut of coating, to lower porosity and also to keep the level of hardness at the next isothermal annealing.
The problems of thermal strengthening of forged pieces of (a + A)-titanium alloys depending on previous conditions of deformation and also on after-deformation annealing of castings are studied. The evaluation of mechanical characteristics of alloy BT23 in forged pieces of different thickness depending on location of zone by cut is given.
Тhе technological aspects of elevation of complex of the articles mechanical characteristics, including weld ones, of (а-ф) titanium alloy BT23 in the process of thermal treating are examined. The problem of industrial use of half-finished products and products with wide palette of structures of plate type in strengthened state is studied due to investigation of advantages and deficiencies of each one.
Tribune of chief metallurgist
Production news
The experimental activation of the sand regenerator of the firm SINTO is carried out at ОАО “MZOO". It is shown that sand grains are cleared from films of binding agents, that allows to use the treated sand for preparation of agglutinant and core sands.
ISSN 2414-0406 (Online)