PhysicalTechnical Institute of National Academy of Sciences Belarus
Physical-Technical Institute of National Academy of Sciences Belarus, Minsk http: //www. phti. belhost. by Е-mail: phti@tut. by Tel/fax: (+375 -17 -263 -76 -93) Founded 1931 Personnel 370 Laboratories- 30 Activity lines: 1. New materials for machine building 2. New technologies for thermal and deformation processing of materials Praha AIP 02 12 2008 1
Physical-Technical Institute of National Academy of Sciences, Belarus, Minsk Praha AIP 02 12 2008 2
Physical-Technical Institute of National Academy of Sciences, Belarus, Minsk Artur Pokrovsky «Investigation and optimization of iron deformability» (Example of unusual action on traditional material) Praha AIP 02 12 2008 3
Iron, classical approach: q Excellent casting material q Hardly deformable q Material only for non-critical items New view on iron: 1. Deformed iron enters the class of materials of high quality 2. Has superior properties 3. Its area of applications is wider 4 Praha AIP 02 12 2008
Iron benefits as compared to steel 1. 2. 3. 4. Higher thermal conductivity results in rapid heat sink (cylinder sleeves, guide valve sleeves) Antifriction properties (camshafts, crank shafts, piston rings) Quicker damping of vibrations and sounds (valve pushers) Lighter by 10% (casings, pallets) 5 Praha AIP 02 12 2008
Drawbacks of iron: q Low mechanical properties q Casting defects degrading the properties 6 Praha AIP 02 12 2008
Traditional means of increasing mechanical properties of iron: Alloying q Modifying q Thermal treatment q Quality of a casting, Casting defects: Problems do not vanish 7 Praha AIP 02 12 2008
Advantages of deformation processing : 3. Accuracy of shaping 2. Increase of strength characteristics 1. Guaranteed quality of metal 8 Praha AIP 02 12 2008
Physical-Technical Institute of National Academy of Sciences, Belarus, Minsk Why we turn to deformation of iron : • • • Casting defects such as pores and cavities are avoided Mechanical properties are enhanced up to the level of alloyed steel (strength is 1200 MPa, elongation 15%) Antifriction characteristics are increased by a factor of 1. 5 Praha AIP 02 12 2008 9
Control of graphite shape Traditional approach: Change of graphite shape from branchy to compact and spherical ones 10 Praha AIP 02 12 2008
Control of graphite shape on deforming And vice versa, from spherical shape to fibers 11 Praha AIP 02 12 2008
We tested the following classes of irons : Gray iron Malleable iron Mottled iron High-strength iron And have found the most ADVANTAGEOUS ONES 12 Praha AIP 02 12 2008
Problems: Temperature parameters of deforming Steel: 1200 – 800 ОС (Δ 400 ОС) Irons : 950 – 850 ОС (Δ 100 ОС) 13 Praha AIP 02 12 2008
Temperature parameters 14 Praha AIP 02 12 2008
Conditions of iron deforming There are 5 groups of «know-how» : 1. Alloying diagrams 2. Preliminary thermal treatment for improvement of deformability 3. Design of press-forging tool 4. Temperature-force parameters of deforming 5. Finishing thermal treatment 15 Praha AIP 02 12 2008
Example of deliberate selection of parameters for iron deforming Part: body of drill chuck Press forging from a solid billet FOR ONE STROKE 16 Praha AIP 02 12 2008
Example of violating the iron deforming conditions Part: Cylinder of jack plunger for MAZ truck Spoiled product (press-forging temperature is violated) 17 High-quality semifinished product Praha AIP 02 12 2008 Finished part
Schematic diagram of iron deforming 1 – Iron billet heated to high temperature 2 – Body of press tool 3 – Intermediate medium 4 - Punch 5 – Die 6 - Guide bush 18 Praha AIP 02 12 2008
Making the samples for investigations Longitudinal samples: Incoming casting billet Transverse samples: Press-forged rod 19 Praha AIP 02 12 2008
Wearing weight loss during dry friction, deformed condition: (Decrease by a factor of 1. 5 as compared that in casting condition) In order of decreasing wear resistance: 1. Mottled iron, (Mt. I) 2. High-strength iron, (HSI) 3. Malleable iron, (MI) 4. Gray iron, (GI) 20 Praha AIP 02 12 2008
C se ros ct s io n Lo se ng ct it io ud n in al Significant feature of deformation is anisotropy of structure and properties 21 Praha AIP 02 12 2008
Anisotropy of wear during dry friction The selection is made of optimum relationships between: Longitudinal sample Transverse sample 22 Praha AIP 02 12 2008 l Deformation parameters l Microstructures l Friction directions
Dry Friction: Coefficient of friction can be decreased by a factor of 2. 5 Longitudinal Transverse sample 23 Praha AIP 02 12 2008
Probable factors that cause improvement of deformed iron characteristics: 1. 2. 3. 4. Refinement of austenite grain Change in pearlite morphology Change in graphite morphology Origination of new graphite inclusions 24 Praha AIP 02 12 2008
1. Refinement of austenite grain Grain number 3 -4 Grain number 8 -9 25 Praha AIP 02 12 2008
2. Changes in pearlite morphology х 10000 х 15000 26 Praha AIP 02 12 2008
3. Changes in graphite morphology 27 Praha AIP 02 12 2008
4. Formation of new graphite inclusions 28 Praha AIP 02 12 2008
Physical-Technical Institute of National Academy of Sciences, Belarus, Minsk Industrial testing of deformed iron Various parts have been offered but the greatest interest has been shown in 2 lines (that will be discussed below): Praha AIP 02 12 2008 29
Physical-Technical Institute of National Academy of Sciences, Belarus, Minsk High-quality billets of piston and sealing rings made from deformed iron q q q Their mechanical properties are 2 times higher than those of cast rings Any failures are absent 7 -fold decrease of lubricant bleeding No wear increase of mating part Stable and one and the same quality throughout the whole height Praha AIP 02 12 2008 30
Appreciation in Belarus and Russia 31 Praha AIP 02 12 2008
Physical-Technical Institute of National Academy of Sciences, Belarus, Minsk High-quality billets of gears made from deformed iron • Strength is at the level of alloyed steel • Noise in trucks is lower by 3 to 4 db • Weight of gears is lower by 9 % (the economy for one set is 700 g) Praha AIP 02 12 2008 32
Disadvantages of technology Ø High power requirements. A billet is to be heated. Ø Some time is required for designing, fabricating and adjustment of press-forging tool. Ø Costly press tool. Ø Economically sound are: Both mass production from 50 thousand pc per year (e. g. , gears for MAZ) and piece production (e. g. , piston rings «Formula-1» ). 33 Praha AIP 02 12 2008
Present-day investigation problems: 1. Technological directional thrust is ahead of fundamental knowledge. 2. The factors that cause iron hardening are still not completely cleared up. 3. The role played by structure factors in hardening is ambiguous. 34 Praha AIP 02 12 2008
We are in search of potential partners for: l Performing joint scientific investigations l Cooperation in delivering billets made from deformed iron. 35 Praha AIP 02 12 2008
From the scientific viewpoint we are interested in: Ø Ø Ø Physical factors and mechanisms responsible for iron hardening during hot deformation Computer simulation of iron hardening processes; Tribotechnical tests Investigation of iron physical characteristics Construction of mathematical models of structure formation Investigation of fine structure (dislocations and point defects). 36 Praha AIP 02 12 2008
From the practical viewpoint we are interested in: l l l Widening the area of deformed iron use as an effective competitive alternative to steel roll stock for manufacturing automotive and machinebuilding parts Joint realization of our technological developments during production of items from deformed iron with improved characteristics We are now prepared to produce rods for investigations as well as gear and sealing ring billets of various typical sizes 37 Praha AIP 02 12 2008
Contacts: l Physical-Technical Institute of National Academy of Sciences of Belarus l 10 Kuprevich St. , Minsk, 220141, Belarus l Artur I. Pokrovsky, Cand. Tech. Sci. , Leading Scientific Worker l Tel. : +10375 -29 -663 -58 -38 l Е-mail: arturu@tut. by 38 Praha AIP 02 12 2008
Thank you for attention! 39 Praha AIP 02 12 2008
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