The method of complex hardening
The invention relates to mechanical engineering and can be used to improve the fatigue characteristics of parts from titanium alloys, in particular of compressor blades of GTE made of wrought titanium alloys. A method for complex hardening of parts from titanium alloys, including shot blasting with subsequent thermal treatment, while blasting treatment on the treated area of the sheet exercise speeds of 30-70 m/C for 30-60 s, and as a heat treatment to spend for 3-6 hours at a temperature of not lower operational and not higher than 450°C. In preferred embodiments of the invention blasting may be made of glass and/or metal beads with a diameter of 50-400 μm, the temperature of the leave is 300-450°C, and as parts of titanium alloys using blades of the compressor turbine engines. The invention improves the fatigue limit due to the complex hardening of titanium alloys. 2 C.p. f-crystals, 1 tab., 2 Il. The invention relates to mechanical engineering and can be used to improve the fatigue characteristics of parts from titanium alloys, chastnostb>Known methods of surface plastic deformation of metal parts and glass shot (balls), dispersed by compressed air, liquid or rotating blades blast wheel. TTD can improve the fatigue detail by pointing in a thin surface layer of residual compression stress, work hardening, and "healing" (smoothing, rounding) surface microdefects (verbov, scratches, pores, etc.) (see Odintsov L., Hardening and finishing details by surface plastic deformation. The Handbook. - M.: Mashinostroenie, 1987, S. 242-250).The efficacy of the DPP is limited not only by an elastic-plastic state of the surface layer parts that carry the features of the previous treatments (so-called technological "heredity"), but the presence of the design stress concentrators (radii of the edges of the blades). These features do not allow a proper use of the energy possibilities of surface hardening processes, because it can lead to proclaiming edges of the blades.It was found that after TTD hardened surfaces have a high energy and will is the R loads can diffuse into the details, lowering resistance to the emergence of cracks. These factors can lead not only to lower values of durability, but the fatigue limit of the details.The prior art method of heat treatment of titanium alloys products, including mechanical treatment in air or protective environments, the subsequent low-temperature annealing at 450-510°C for 5-10 h with subsequent cooling and polishing (SU 411154, IPC-2 C 22 F 1/18, 15.01.1974, formula).The disadvantages of this method include the fact that the annealing allows only to neutralize the negative effects of mechanical processing, but to create an optimal controlled quality of the surface layer can only superficial hardening, the use of which in the author's evidence is missing.Closest to the claimed method is a method of machining of titanium alloys, including shot blasting the beads with a diameter of 160-200 μm at a pressure of 2.5-3 ATM for 5-6 min, followed by annealing at 550±10°C for 4-7 min (SU 872595, IPC-3 C 22 F 1/18, 15.10.1981, formula).The disadvantage of this method is that the residual compressive stress and the work hardening that occurs when shot peened on the ProcName, since the maximum allowable temperature, which is an effect of hardening
450°C. Further, the exposure time of the annealing (5-7 min) is not sufficient to neutralize the adsorbed oxygen on the surface, diffusing into it, and thereby causing an accelerated growth of fatigue cracks.The objective of the invention is to increase the fatigue limit of parts from titanium alloys.The objective of the invention is achieved by the implementation of the method of complex hardening of parts from titanium alloys, including shot blasting with subsequent thermal treatment, according to the invention blasting treatment on the treated area of the sheet exercise speeds of 30-70 m/C for 30-60 s, and as a heat treatment to spend for 3-6 hours at a temperature of not lower operational and not higher than 450°C.In a preferred embodiment, the method of shot blasting conducting glass and/or metal beads with a diameter of 50-400 μm.In a preferred embodiment of the invention, the temperature of the leave is 300-450°C.In a preferred variant of the invention, the parts made of titanium alloys useddock on the treated area of the sheet i.e. at the site equal to the diameter of the torch fraction. After processing one portion of the items within 30-60 spend processing the next unprocessed area details within 30-60 and so until then, will not be processed until the entire part. This is due to the fact that the workpiece can be of different shapes and sizes and sometimes it is not possible to process the entire part at the same time because of insufficient diameter of the torch fraction.Integrated hardening, reducing the value of the residual compression stress and work hardening by 25-30%, formed after injection at the same time, reduces their variance, which is based on technological "inheritance" from 25-100% 30-40%, i.e., along with the decline, is aligned over the entire surface detail, which is especially important for the design of the hub, because it prevents them from proclip, as well as the technological hub, removing the sharp transition of the stress values. In addition, the reduction and equalization of stresses leads to a decrease leashes detail, ensuring its value within the specified tolerance.Combined hardening provides a "compacted" and reasonably "oriented" homogeneous structure with fine grain, EF is ska adsorbed oxygen is bound in stable chemical compound (Tio2), not allowing it to diffuse into the surface. Which reduces the likelihood of subsurface cracks.The following examples illustrate, but not limit application of the claimed method.Effectiveness of complex hardening was carried out on the blades of titanium alloy VTZ-1, made in accordance with OST1 90002-86, the minimum radius of the edges of which was equal to Rto=0,2-0,22 mmThe following table shows the modes pneumogastric processing (DTP) and the subsequent tempering blades.In Fig.1 and 2 presents the results of the experiment, allowing to evaluate the effectiveness of an integrated hardening.The experiment showed that the padding on modes 1 and 2 gives the greatest effect compared to less intensive modes. When changing modes in the direction of increasing their energy parameters (modes 1.1 and 2.1) has a drop fatigue limit compared to modes 1 and 2 with 460-480 MPa to 430-440 MPa.Integrated reinforcement profiles 1.3 and 2.3) allows to obtain the highest values of the fatigue limit of 540 MPa, which corresponds to a residual compression stress value of 200-300 MPa and a depth of 40-60 microns.The choice of modes blasting simplified in order to obtain their most rational values for specific sections of the radii of the edges of GTE blades.Modes hardening adjusted towards reducing their energy level because of the tendency of higher values of the quality parameters to relax more intensively and, thereby, reduce the hardening effect.When assigning temperature must assume that it must be not lower operational and not to exceed 450°C, because above this value the hardening effect disappears (according to mode 1.4 increasing the tempering temperature up to 450°C caused a decrease of the fatigue limit to 510 MPa).
Claims
1. The method of complex hardening of parts from titanium alloys, including shot blasting with subsequent heat treatment, characterized in that the blasting treatment on the treated area of the sheet exercise speeds of 30-70 m/C for 30-60 s, and as a heat treatment to spend for 3-6 hours at a temperature of not lower operational and not higher than 450°C.2. The method according to p. 1, characterized in that the blasting treatment is carried out, the glass and/or metal beads with a diameter of 50-400 μm.3. The method according to p. 1 or 2, characterized in that t is of titanium alloys using blades of the compressor turbine engines.
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FIELD: mechanical engineering; piston internal combustion engines.
SUBSTANCE: invention relates to valve of internal combustion engine, method of its manufacture and heat-resistant titanium alloy used for manufacture of valve consisting of following components, mass %: aluminum 7.5-12.5; molybdenum 1.6-2.6; zirconium 1.4-2.4; silicon 0.1-0.2' yttrium 0.005-0.1; titanium - the rest. It has α+α2+β phase composition with intermetallide α2 phase on Ti3Al base dispersed in α phase. Proposed method includes forming of valve from cylindrical blank by deformation machining with preliminary heating and subsequent heat treatment. Preliminary heating of part of blank related to rod done to temperature 5-20oC lower than temperature of complete polymorphic transformation of alloy, and its deformation machining is carrying out by wedge cross rolling. Deformation machining of part of blank related to head is done by forging with preliminary heating to temperature 5-50oC higher than temperature of complete polymorphic transformation of alloy corresponding to beginning of forging, and forging is finished at temperature lower than complete polymorphic transformation of alloy to form plate head of valve and transition section provided smooth changing of head into rod. Invention provides designing of valve, method of its manufacture and heat-resistant alloy used in manufacture of valve making it possible to operate valve within operating temperature range owing to increased long-term strength and creep resistant of valve head material and increased strength, modulus of elasticity and hardness of valve rod material.
EFFECT: improved quality of valve and increased reliability in operation.
16 cl, 3 tbl, 1 ex, 15 dwg
FIELD: manufacture of metallic articles, particularly of hard-to-form intermetallic alloys, possibly electric resistive heating members.
SUBSTANCE: article is made of aluminides of iron, nickel and titanium. Method comprises steps of subjecting article being cold worked to cold hardening; performing rapid annealing at seasoning less than 1 min; repeating operations of cold working and rapid annealing for receiving article with desired size. It is possible to make article by casting, powder metallurgy process or plasma deposition.
EFFECT: enhanced strength of article.
26 cl, 4 dwg
FIELD: metallurgy, in particular feed from titanium-based alloy for aircraft industry and engineering.
SUBSTANCE: claimed method includes feed heating, deformation thereof in die, heated to temperature of total titanium-based alloy polymorphous conversion or above: isothermal holding at die temperature for time effective to total titanium-based alloy recrystallization; and quench. Feed is heated up to temperature by 10-30oC lower than the same of total polymorphous conversion; deformation is carried out in two steps: in the first one deformation rate is sufficient to feed heating up to die temperature, and deformation degree is 30-60 %, and in the second one rate is 10-2-10-4 s-1, and deformation degree is 10-30 %; isothermal holding is carried out under pressure of 10-150 MPa.
EFFECT: strained feed with homogenous recrystallized structure and β-grain size of 10-30 mum; with high strength and improved coefficient of metal utilization.
5 cl, 2 tbl, 1 ex
FIELD: deformation-heat treatment of metal with change of its physical and mechanical properties, possibly in machine engineering, manufacture of air craft engines and in medicine for making semi-finished products of titanium.
SUBSTANCE: method comprises steps of intensive plastic deformation in mutually crossing ducts and further mechanical working of blank. Mechanical working is realized by multiple rolling or extrusion at 20°C at reduction degree in one pass causing no main cracking and material destruction. Number of passes of rolling or extrusion provides final deformation degree 80- 90 %.
EFFECT: manufacture of ultra-fine grain titanium sheet blanks with improved fatigue limit value at the same strength and working ductility.
1 dwg, 1 ex
FIELD: aircraft industry; mechanical engineering; methods of metals plastic working.
SUBSTANCE: the invention is pertaining to the methods of metals plastic working, in particular, to production of blanks for units of a gas turbine engine and may be used in production of aircraft engines and in mechanical engineering. The method includes heating of a high-temperature resistant alloy bar and its straining during several runs. For obtaining a homogeneity of the blank chemical composition and structure in the whole volume of the blank and for increasing the alloy mechanical properties during the blank subsequent machining at least one run is conducted at the temperature exceeding the temperature of the beginning of the alloy hardening inter-metallic phase dissolution. Then, they conduct a press forming in the interval of the temperatures from the temperature of a recrystallization process start to the temperature of the recrystallization process end for production of the uniform fine grained structure, that ensures a high level of general physical-mechanical properties of the blank and the item as a whole.
EFFECT: the invention ensures production of the uniform fine-grained structure and a high level of general physical-mechanical properties of the blank and the item as a whole.
2 ex
FIELD: non-ferrous metallurgy; methods of thermal treatment of items or blanks made out of the two-phase titanium alloys titanium alloys.
SUBSTANCE: the invention is pertaining to the field of metallurgy, in particular, to the method of thermal treatment of an item or blanks made out of the two-phase titanium alloys titanium alloys. The offered method of thermal treatment of an item or a blanks made out of the two-phase titanium alloys provides for their heating, seasoning and chilling. At that the item or the blank is heated up to the temperature of (0.5-0.8)tag , where tag is the temperature of the alloy aging, and chilling is conducted from -10 up to -20°С at simultaneous action of a gas current and an acoustic field of an acoustical range frequency with a level of the sound pressure of 140-160 dB. The technical result is the invention ensures an increased strength of items or blanks at keeping the satisfactory plastic properties.
EFFECT: the invention ensures an increased strength of items or blanks at keeping the satisfactory plastic properties.
7 cl, 1 dwg, 1 tbl, 1 ex
FIELD: metallurgy, namely processes for forging titanium alloys and blank of such alloy suitable for forging.
SUBSTANCE: method comprises steps of preparing blank and forging it. Forging is realized at providing mechanical hardening factor equal to 1.2 or less and at difference of hardness values between central (along width) zone and near-surface zone equal to 60 or less by Vickers. Factor of mechanical hardening is determined as HV(def)/HV(ini), where HV(ini) - hardness of titanium alloy blank before forging; HV(def) -hardness of titanium alloy blank after forging at forging reduction 20%. Forging may be realized at deformation rate from 2 x 10 -4 s -1 to 1s-1 while keeping relations (T β - 400)°C ≤ Tm ≤ 900°C and 400°C ≤ Td ≤ 700°C, where Tβ (°C) -temperature of β-phase transition of titanium alloy, T m(°C) - temperature of worked blank; Td(°C) - temperature of die set. Blank has factor of mechanical hardening 1.2 or less and difference of hardness values between central (along width) zone and near-surface zone equal to 60 or less by Vickers.
EFFECT: possibility for forging titanium alloy blanks at minimum difference of material properties along depth, simplified finishing of blank surface after forging, reduced cracking of blank material, good workability of blank with favorable ductility and fatigue properties.
8 cl, 5 tbl, 6 dwg, 4 ex
FIELD: non-ferrous metallurgy; methods of titanium alloy bricks production.
SUBSTANCE: the invention is pertaining to the field of non-ferrous metallurgy, in particular, to the brick made out of α+β titanium alloy and to a method of its manufacture. The offered brick consists of the following components (in mass %): aluminum - 4-5, vanadium - 2.5-3.5, iron - 1.5-2.5, molybdenum - 1.5-2.5, titanium - the rest. At that the alloy out of which the brick is manufactured, contains - 10-90 volumetric % of the primary α-phase. The average grain size of the primary α-phase makes 10 microns or less in a cross-section plain parallel to the brick rolling direction. Elongation of grain of the primary α -phase is the four-fold or less. The offered method of manufacture of the given brick includes a stage of a hot rolling. At that before the stage of the hot rolling conduct a stage of the alloy heating at the surfaces temperature (Tβ-150)- Tβ°C. During realization of the stage of the hot rolling the surface temperature is kept within the range of (Tβ-300)-( Tβ -50)°C, and the final surface temperature, that is a surface temperature directly after the last rolling, makes (Tβ-300)-( Tβ-100)°C, where Tβ is a temperature of α/β-transition. The technical result of the invention is formation of a brick out of the high-strength titanium alloy having a super pliability, excellent fatigue characteristics and moldability.
EFFECT: the invention ensures production of a brick out of the high-strength titanium alloy having a super pliability, excellent fatigue characteristics and moldability.
7 cl, 7 dwg, 21 tbl, 2 ex
FIELD: processes and equipment for diffusion welding of tubular adapters of zirconium and steel sleeves.
SUBSTANCE: method comprises steps of placing sleeve of zirconium alloy inside steel sleeve and heating them in vacuum till diffusion welding temperature; then compressing welded surfaces due to expanding zirconium sleeve by means of roller expander; after diffusion welding cooling adapter in temperature range in which zirconium alloy has no phase containing α-zirconium and β-zirconium; subjecting zirconium sleeve to hot deformation by depth no less than 0.5 mm at reduction degree no less than 10%; cooling adapter till temperature range 540 - 580°C and keeping it in such temperature range no less than 30 min.
EFFECT: simplified method for making adapters having improved corrosion resistance in hot water and steam.
FIELD: plastic metal working, possibly manufacture of intermediate blanks of titanium alloys by hot deforming.
SUBSTANCE: method comprises steps of deforming ingot at temperature in β -range and combination type operations of deforming blank temperature of (α + β) and β-ranges; at final deforming stage at temperature in (α + β) range realizing at least one forging operation after heating blank till temperature that is lower by 50 - 80°C than polymorphous conversion temperature of alloy; at least one time cooling blank in water; before deforming blank for final size, heating blank till temperature that is lower by 20 - 40°C than polymorphous conversion temperature for time period providing globule formation of α - phase; fixing formed structure by cooling in water; again heating blank till temperature that is lower by 20 - 40°C than polymorphous conversion temperature and finally deforming blank.
EFFECT: possibility for producing blank with globular-plate microstructure, lowered level of structural defects at ultrasonic flaw detection of turned blank.
1 ex
