One  of  the  important  reasons  for  the  downtime  of  ball  rolling  mills  is  replacement  of  rolls  due  to  their  wear  and  tear.  The  degree  and  zones  of  critical  wear  of  ball  rolling  rolls  are  investigated  in  the  article, where the greatest wear is observed over the flanges in zone of billet  capture.  Conditions  necessary  to  capture  the  blank  and  to  perform  rolling  process  are  analytically  determined.  Variable  frequency  method  of  roll  rotations  is  proposed  as  a  progressive  technology  for  blank supply. The results of tests for its variations in accordance with  linear  and  quadratic  law  are  presented.  Known  formulas  determining  average  strain  rate  at  rolls  rotational  speed  change  are  converted  for  linear and quadratic dependences. Experimental studies have been carried  out  in  conditions  of  EVRAZ  Nizhnetagilsky  Metallurgical  Plant  ball rolling mills during rolling of 60mm ball made of Sh-3G steel. Experiments  were  performed  for  given  parameters  of  manual  change  in  rolls rotation speed at blank capture by rollers. The results have shown  a  significant  effect  of  change  in  rotational  speed  on  average  specific  pressure during blank capture. Evaluation of torque-time and average  contact  pressure  for  calculated  and  experimental  data  are  presented.  Empirical characteristics are also described at variable rotational speed  of rolls according to linear and quadratic law. Acceptable convergence  of results of calculated and empirical characteristics is determined. Engineering solution has been proposed for that task. It consists in installation of a thyristor converter. This solution allows reduction of rolls  speed before blank capture. Also, this solution will increase frequency  to  the  nominal  value  according  to  the  given  law  after  blank  capture.  As an obtained result, there is uniform distribution of average contact  pressure over the entire length of the roll under different operating conditions  of  mill  in  automatic  mode. Application  of  this  technique  will  reduce wear degree of the rolling tool. At the same time, productivity  of ball rolling mill will be maintained. Rolls consumption and number  of rolls change will decrease due to rolls wear.

One of the directions of increasing production efficiency in ferrous  metallurgy  is  reduction  of  expensive  and  scarce  ferroalloy  consumption.  Great  opportunities  in  that  direction  are  provided  by  technology  of  direct  steel  alloying  by  oxide  materials.  Thermodynamic  study  of  the  process  of  direct  steel  alloying  by  manganese  oxide  materials  (manganese  ore)  and  industrial  testing  of  that  technology  has  been done in that work. Two options of direct alloying technology have  been considered: during steel melting in modern 100-ton EAF in oxidative conditions and during processing of steel on ladle furnace (LF)  in reductive conditions. Thermodynamic modeling of oxidative technology  option  by  TERRA  software  package  has  shown  that  there  is  opportunity to increase content of manganese in metal by manganese  ore  injection.  Key  factor  in  that  process  is  current  carbon  content  in  steel.  Content  of  manganese  can  be  raised  up  to  0.6 %  and  more  in  medium and  high-carbon  steel.  Residual  manganese  in  low-carbon  steel is defined by value of carbon content in the end of oxygen lancing. Graphic dependence is provided. MnO + Si = Mn + SiO₂ is main  reaction  of  the  process  of  direct  alloying  under  reductive  conditions.  Thermodynamic analysis gives very rough data. That is why semi-empirical analysis was performed, which was based on received industrial  results of FeO and MnO proportion contained in slag in the end of steel  processing at LF. That way of process estimation is considered reasonable, because of approximation to balance of metal-slag system during  long processing of steel at LF. Using this proportion, and conditions of  slag initial basicity retaining and maintaining of FeO content in slag at  level  around  1 %,  balance  equation  describing  process  of  direct  steel  alloying  by  manganese  ore  at  ladle  was  derived.  This  equation  helps  to calculate basic technological parameters of the process of direct alloying  by  manganese  ore  as  applied  to  specific  conditions  of  production.  Good  convergence  of  theoretical  calculation  and  practical  data  has been received.

Composite  materials  (CM)  are  widely  used  for  hardening  of  wearing parts operating at high temperature wear types. They are based  on  high-melting  hard  alloys,  as  which  are  used  carbides  of  transition  metals  of  IV – VI  groups A  determining  the  physics  of  high-temperature wear. For these purposes baked TiC of TN 20 type on the basis  of (Ti, Mo)C – Ni – Mo is used that has a ring structure preventing the  formation of complex alloyed structures on the bounda ry of solid particle-matrix. Due to the minimal solubility of the sintered hard alloy of  TN 20 type in the alloy-bond, at the interface of solid particle – matrix  practically does not stand out complex structural phases causing embrittlement and growth of residual thermal stresses and strains. It leads  to increased wear resistance and longer service life of hardened parts.  In order to increase the opera ting efficiency of metallurgical units due  to  hardening  of  spare  parts  with  a  composite  material  based  on  sintered hard alloy of the TN 20 type using electroslag surfacing (ESW),  a comprehensive program has been developed to control the efficiency  of hardening parts. In the management of hard alloy surfacing the special  attention  is  given  to  heat  and  high  temperature  wear  resistance  determined  by  the  set  of  CM  properties  of  solid  particles.  Therefore,  maintaining of high mechanical, thermal and energy characteristics of  carbides and decrease of the solubility of solid particles in a CM matrix  at surfacing is a priority for improving efficiency in hardening process  of spare parts. Integrated ESW management program for CM is based  on  effects,  aimed  to  prevent  the  formation  of  complex  alloyed  structures on surface of the solid section of particle-matrix; to reduce thermal stresses and deformations (leading to the cracks formation, chipping and deleting solid particles in abrasive wear) and to improve high  temperature wear resistance. Use of the developed control systems for  hardening  process  of  metallurgical  equipment  wearing  parts  has  significantly  increased  the  service  life  of  spare  parts  and  producti vity  of  the metallurgical units, which ensured a certain economic effect.

Billets from high-chromium steels possessing the necessary complex of mechanical and corrosion properties are widely used in the manufacture of critical products of heavy and power engineering. One of the effective technologies widely used in the manufacture of such work-pieces is electroslag remelting (ESR). ESR, included in the production process chain, for the management of refining and solidification processes allows to ensure a high homogeneity of metallurgical characteristics (chemical composition, structure, non-metallic inclusions, etc.) of the metal and, as a result, the complex of mechanical properties of the product. The choice of slag, maintaining its optimum oxidation-reduction potential at an optimum level, is a prerequisite for the effective refining of high-chromium steels at the ESR, since chromium and other elements present in the slag in various oxidation degree participate in the transport of oxygen from the gas phase to the liquid metal. From standpoint of the theory of electronic structure of slag systems, the effect of slag oxidation (equilibrium partial pressure of oxygen Р_O2 ) on the oxidation degree of chromium has been studied for widely used slags in Russia such as ANF-1, ANF-6, and ANF-29. Dependence of the ratio of Cr⁺³/Cr⁺² concentrations on the temperature, oxidation level and optical slag basicity is established. A thermodynamic model of changing the oxidation state of chromium in slag depending on its oxidation is presented. The calculated results are compared with the experimental data for slag systems at a temperature of 1873 K. It is shown that the average oxidation degree of chromium decreases with increasing temperature, decreasing of the oxygen partial pressure and the optical slag basicity. The presence of fluorine in the slag affects the varia- tion ratio Cr⁺³/Cr⁺². It is shown that with decrease in the oxygen partial pressure from 10^-4 to 10^-12Pa at a temperature of 1873 K, the average value of chromium oxidation degree in fluoride-oxide slags decreases from +3 to +2. A correlation is proposed, which makes it possible to estimate the Cr⁺³/Cr⁺² ratio in fluoride-oxide slags, taking into account the temperature and oxidation of slag.

One of the major causes of downtime ball-rolling mills is the replacement of the rolls due to their wear. The paper studies the extent and the critical wear areas of ball-rolling rolls. The conditions required for gripping the work and performance of the rolling process are determined. A method for variable roll speed when submitting blank  is and the test results are given when the roll speed  is modified according to linear and square law.
Experimental studies have been conductedin the ball-rolling mill "EVRAZ NTMK" and show a significant effect of changes in speed on the average specific pressure. Engineering solution to solve this problem is suggested as the installation of thyristor converter. The use of this technique will reduce the degree of wear of the rolling tool at the same performance.

Work-pieces from high-chromium steels possessing the necessary complex of mechanical and corrosion properties are widely used in the manufacture of critical products of heavy and power engineering. One of the effective technologies widely used in the manufacture of such work-pieces is electroslagremelting (ESR).

The choice of slag, maintaining its optimum oxidation-reduction potential at an optimum level, is a prerequisite for the effective refining of high-chromium steels at the ESR, since chromium and other elements present in the slag in various oxidation degree participate in the transport of oxygen from the gas phase to the liquid metal.

From the standpoint of the theory of the electronic structure of slag systems, the effect of slag oxidation (the equilibrium partial pressure of oxygen Ро₂) on the oxidation degree of chromium has been studied for widely used slags of Russia such as ANF-1, ANF-6, and ANF-29.The dependence of the ratio of Cr⁺³/Cr⁺² concentrations on the temperature, oxidation level and optical basicity of the slag is established.

The calculated results are compared with the experimental data for slag systems at a temperature of 1873 K. It is shown that the average oxidation degree of chromium decreases with increasing temperature, a decreasing of the oxygen partial pressure and the optical basicity of the slag. It is shown that the presence of fluorine in the slag affects the variation ratio Cr⁺³/Сr⁺².

Common  method  of  oxidized  nickel  ores  processing  includes  ore feeding in countercurrent with high-temperature waste gases, melting in bubbling zone of a two-zone furnace, supplying carbonaceous  fuel and oxygen-containing blasting to produce melt that is reduced by  solid  reducing  agent  in  plasma  zone  when  heated  with  nitrogen.  The  main disadvantages of this method are low nickel content in alloy and  presence  of  silicon,  carbon,  chromium  and  other  impurities.  To  improve quality of ferronickel, it is proposed to use converted natural gas  in  plasma  zone,  which,  when  processed  by  plasma,  is  not  only  a heat  carrier,  but  also  a  reducing  agent.  The  method  is  based  on  assumption that at melt bubbling, composition of gas in bubbles that reached  bath surface is close to equilibrium. Gas-reducing agent is obtained by  oxygen conversion of natural gas with ratio α equal to 0.25; 0.35 and  0.50  respectively  (T = 1823 K).  Based  on  calculations,  dependencies  of content of nickel and iron oxides in silicate melt, degree of their reduction, ratio of slag and metal and nickel content in the alloy on total  gas flow determined as the product of the gas amount in a single batch  and the number of calculation cycles, as well as the amount of nickel  and iron, reduced by a single portion of gas are revealed. Regardless of proportion of hydrogen and carbon monoxide in source gases, increase  in  their  consumption  monotonously  reduces  content  of  nickel  oxide  in  the  melt,  while  content  of  iron  oxide  initially  increases,  and  then  decreases.  When  melt  is  blown  with  natural  gas  conversion  products  with  α = 0.25,  reduction  process  takes  place  due  to  hydrogen,  effect  of  CO  is  insignificant.  Flow  rate  of  54 m³/t  of  gas  allows  to  achieve  98.5 %  degree  of  nickel  reduction,  content  of  nickel  oxide  in  melt  is  0.028 %, ratio of slag and metal is 46 units. At equal gas consumption,  with increase in proportions of CO₂ and H₂O in the initial mixture, by  increasing α, values of metals reduction from melt deteriorate: valu es  of  C_NiO  and  C_FeO  and  ratio  of  slag  and  metal  increase,  and  degree  of  nickel  and  iron  reduction  decreases.  Comparison  of  results  with  previously  obtained  data  on  metals  reduction  from  similar  melts  by  carbon monoxide and hydrogen has shown that hydrogen has greater efficiency, somewhat worse results are demonstrated when converted gas  with α = 0.25 is applied. Nickel reduction by converted gas (α = 0.35)  to reduction rate of 88 %, which corresponds to its consumption of  60 m³/t,  is  more  effective  than  by  pure  CO.  However,  final  values  of  degree of reduction using converted gas reach 90 %, while for CO they  approach 100 %.

Regularities of the effect of maximum value of stress-strain state,  obtained under conditions of cold forced fit of blanks of the shaft-hole  system during formation of solid-phase diffusion bond (SDB) and subsequent  modes  of  temperature  action  in  autonomous  vacuum,  are  investigated on evolution of structural changes and properties of contact  area  (CA)  of  solid  joints  of  OT4-1  alloy.  It  is  shown  that  under  cold  plastic  deformation  of  OT4-1  alloy,  formation  of  SDB  in  microstructure of CA leads to generation of deformation relief (traces of sliding  along  the  grain  boundaries),  decrease  in  contact  surfaces,  and  to  volume interaction, both in the plane of contact (curvature of grains) and  in  volume  of  contact  zone  (outbreaks  of  dislocations).  The  main  parameters  (specific  parameter  of  structure  organization,  grains  density,  average density of grain boundaries, development of grain boundaries)  exceed  those  of  the  initial  state  of  base  metal  in  10,  4,  1.8,  1.5 times  respectively. Temperature influences under conditions of autonomous  vacuum in the interval of phase transformations α → β lead to staging  of structural changes, both in the main metal and in SDB contact area.  At the initial moment, globular component appears in microstructure,  which  again  goes  back  to  acicular  structure  of  the  initial  state  (with  some  increase  in  microhardness)  with  increase  in  holding  time,  and  also  with  increase  in  temperature.  For  the  first  time,  phenomenon  of  appearance of the globular structure formation stage during heating of  plastically  deformed  metal  is  established  not  only  under  temperature  and  time  conditions  of  phase  transformation,  but  also  under  elevated temperatures; and the higher heating temperature is, the shorter is lifetime  of  the  stage.  Moreover  with  less  degree  of  plastic  deformation,  stage of structure globularization is observed at temperatures close to  T_pt  and  shorter  exposures.  For  base  metal  (degree  of  deformation  is  insignificant),  globular  structure  disappears  almost  completely  after  heating for 10 min at 950 °C. For stress-strain state of cold-deformed  SDB, globular structure disappears when heated: for 1 hour at 950 °C;  for  40  min  at  975 °C;  for  20  min  at  1000 °С. At  these  temperatures,  process of discontinuities “healing” is almost completed, i.e. bond line  disappears,  and  solid  metal  is  formed  along  the  microstructure  of  the  CA,  not  differing  from  the  basic  metal  with  insignificant  increase  in  microstructure. Quantitative assessment of structural changes in basic  parameters  of  interface  of  structural  state  makes  it  possible  to  reveal  mechanism,  kinetics  and  structural  dependence  on  degree  of  plastic  deformation  and  heat  treatment  regimes,  that  ensure  discontinuities  “healing”,  disappearance  of  interfaces  and  provision  of  SDB  properties no worse than those of basic metal.

Effect of deformation along various directions against migrating  boundary on migration rate of edge boundaries with <100> and <111>  misorientation  axes  in  nickel  was  studied  by  means  of  molecular  dynamics  method.  Grain  boundaries  were  created  in  U-shaped  model.  Force of boundary surface tension, arising from the boundary intension  to  minimize  its  energy,  was  the  reason  of  directed  movement  of  the  boundary toward its area decrease. The force provoking migration and  migration rate of the boundary remained constant throughout the entire  movement  of  the  boundary,  gradually  decreasing  towards  the  end  of  computer  experiment,  which  made  it  possible  to  measure  migration  rate quite simply. Effect of uniaxial deformation along the X, Y, Z axes  on migration rate of the boundaries was considered. Uniaxial deformation in the model was set at beginning of the computer experiment by  changing  corresponding  interatomic  distances  along  one  of  the  axes.  Interactions of nickel atoms with each other were described with the aid  of Cleri Rosato many-particle potential constructed in the framework  of  tight  binding  model.  For  the  boundaries  considered,  dependences  of  migration  rate  on  misorientation  angle  at  temperature  of  1700 K  were obtained. It is shown that the high-angle <111> and <100> edge  boundaries migrate approximately at the same rate, while mobility of  low-angle  boundaries  differs  significantly:  low-angle  <111>  boundaries migrate about twice as fast as the <100> boundaries. It was found  that in almost all cases, both at elastic compression and tension deformation, migration rate of considered boundaries was slowed down. An  exception was the case of deformation along the <111> edge boundary  axis. When compressing along the edge axis, <111> boundary migrated faster, while on the contrary, it was slower at tension. The obtained  results testify to the fact that migration of edge boundaries is not due to  diffusion processes, such as climbing of dislocations, single migrations of  atoms,  but,  apparently,  by  collective  atomic  permutations:  shifts, slides and splittings of grain boundary dislocations.

The literature devoted to cone crushers design and research of  its  crushing  process  is  generally  based  on  empirical  observations,  therefore it is commonly considered that material is crushed under  the  influence  of  squeezing  forces  exclusively.  Above  mentioned  liter  ature, in turn, theoretical base forms for crushing units design.  Based on common understanding, variety of designs of cone crushing  machines  existing  today  is  characterized  by  integrity  of  principles of their work. Majority of theoretical works devoted to cone  crushers are focused on such characteristics as efficiency, extent of  crushing, increase in percent of useful fraction in ultimate product,  or  on  operational  parameters  of  separate  structural  elements  such  as lining armor resistance, increase in endurance of supporting and  power nodes, etc. To increase those characteristics crushing cameras with irregular shape of lining armor are designed, design of an  active  crushing  member  combines  elements  of  active  members  of other crushing machines (roll, cheek crushers). However effectiveness of kinematics of active member movement is considered only  from  the  point  of  view  of  squeezing  forces  generation  in  crushed  material  and  minimization  of  its  slide  against  it.  The  uppermost  ener gy brought to any crushing machines is spent on loa ding destroying crushed material. Authors of this article consider that under  particular  circumstances  such  work  conditions  can  be  provided  in  cone crushers under which energy efficiency of materials crushing  process will increase considerably. One of such conditions is creation  of  multi-axial  stress  in  crushed  material.  Some  reference  designs of cone crushers are considered in the article as well as range  of  their  app lication.  Mechanism  of  multi-axial  stress  generation  in  crushed  material  promoting  decrease  in  energy  consumption  of  crashing  process  is  described.  Recommendations  on  development  of  operating  conditions  of  crushing  machine  creating  multi-axial  stress in crushed material are provided.

The article describes results of the microplot field trial to investigate potential use of metallurgical slags for fracture of capillary rim  during reclamation of toxic waste dumping areas, such as enrichment  plants  tailings,  solid  waste  dumps,  etc.,  with  minimal  possible  introduction  of  fertile  soil  layer.  Such  approach  allows  energy-effective  utilization  of  metallurgical  wastes.  Four  slags,  produced  at  EVRAZ  West  Siberian  plant  by  different  technologies  were  used:  white  nonferrous, blast-furnace, converter and electric furnace slags. These slags  were used as an inert material, underlying thin fertile soil layer in experimental microplots, where perennial plants (legume-grass mixture)  were sawn. For each slag there was check variant (no fertilizer added),  and  variants  with  potassium  humic  agents,  and  their  combination  as  mineral fertilizers. Aboveground phytomass at the end of the grow ing  season varied from 17 to128 g/m2. Converter and blast furnace slags,  which had the least phytotoxicity, appeared to be better inert materials.  Mineral  fertilizer,  introduced  itself  and  combined  with  humic  agents,  has  increased  aboveground  phytomass  2 – 4 times  as  compared  with  check  variant.  Used  separately,  humic  agent  did  not  affect  plant  production,  whereas  used  together  with  mineral  fertilizer,  it  increased  phytomass  1.6 – 1.8 times.  Thus  combined  introduction  of  mineral  fertilizer  and  humic  agents  is  recommended  to  stimulate  germination  abilit y  and  phytomass  production.  Converter  and  blast  furnace  slags  can be used as inert materials for reclamation with minimal fertile soil  layer application, whereas white non-ferrous and electric furnace slags  are not recommended for such application due to their high phytotoxicity, negatively affecting growth and development of perennial plants,  used for reclamation.

Results  of  thermodynamic  modeling  of  the  elements  reduction  from  the  chromium  containing  ore-lime  melt  with  the  use  of  silicon  from ferrosiliconickel as a reducing agent are presented as a function  of temperature. It has been established that an increase in temperature  from  1300  to  2200  °C  helps  to  reduce  the  reduction  degree  of  chromium from 98,9 to 69,8 %.

The article presents high-carbon hypereutectoid steel for production of hot rolling forged rolls. The steel contains 1.2 – 1.4 % of carbon, carbide forming alloying elements Cr, Mo, V and Nb improving  wear  resistance  of  the  rolls,  and  Ni  increasing  hardening  capacity.  It  has  been  found  that  steel  of  proposed  composition  provides  ductility  sufficient  for  hot  deformation  (forging)  by  moderate  single  compressions. Temperature range of ingot deformation has been detected: finite  temperature deformation should not be below 900 °C, forging temperature – 1150 °C. According to its properties steel can be recommended  for manufacturing solid-forged rolls and bandages for composite rolls  of hot rolling from ingots of up to 10 tons weight.