The method of processing pseudo-titanium alloys
The invention relates to ferrous metallurgy, in particular to the processing of titanium alloys. A method for processing a pseudo-titanium alloys, including multi-stage heating and stamping and subsequent cooling, and heating under final stamping produce to a temperature below the temperatureturning to exclude this transformation, and the heat under the final stamping produce to a temperature not lower than 30°C temperaturetransformations and then spend the annealing. The technical result - getting quality parts at the expense of ensuring the uniformity and stability of the mechanical properties of parts as a result of processing. 1 table, 3 Il.
The invention relates to ferrous metallurgy, in particular to a heat treatment of titanium alloys.
A method of processing titanium alloys (SU 396427, C 22 F 1/18, 1973), which includes heated and deformed inarea, +- transformation, exposure at this temperature for 1 hour and further cooling. However, this method does not provide a stable mechanical properties of parts.
There is also known a method of processing titanium alloys (SU 324298, C 22 F 1/18, 1972), in which heating is carried out to a temperature of 30...70°C below the temperature of polymorphic transformation, cooling at a speed of 5...30°C in second, followed by aging at 5000...600°C, which provides improved strength properties at room and elevated temperatures while maintaining high plastic properties. The disadvantage of this method is that the heat treatment in such a wide range of cooling rates can lead to the formation of chemical and structural microheterogeneity, which are often unstable with respect to subsequent heatings. The presence of microheterogeneity determines the uniformity of the mechanical properties of the part.
The closest analogue in essential characteristics and purpose is the way multi-processing pseudo-titanium alloys (SU 1740487 A1, C the fir properties of parts.
The proposed method aims to obtain high-quality parts by providing the processing uniformity and stability of the mechanical properties of parts.
The invention consists in the following. In the processing method of blanking of pseudo--titanium alloys, including multi-stage heating and stamping and subsequent cooling, heating under final stamping produce to a temperature below the temperatureturning to exclude this transformation. However, unlike the prototype heat under the final stamping produce to a temperature not lower than 30°C temperaturetransformations and then spend the annealing. A special condition of the phase predpriyatiya has the lowest stability of atoms for both phases. Heat effects on metal and alloy in the temperature range of predpriyatiya leads to maximum diffusion mobility of atoms. In these conditions occur multilevel relaxation processes, which are fixed p the activity.
The invention is illustrated graphics. The table below shows a comparative analysis of the mechanical properties of parts made similar to the SU 396427, the proposed method and the similar SU 324298. In Fig.1, 2 and 3 presents the microstructure of the material parts of titanium alloy VT20, processed, respectively, similar to the SU 396427, the proposed method and the similar SU 324298.
Billet alloy VT20 the same melting temperature of polymorphic transformation T=975°after the preliminary two-stage stamping subjected to the final third forging after heating them to a temperature of 1100 respectively°C, 970°C and 920°C and subsequent cooling. All the stamping was subjected to annealing at a temperature of 880°C, 1 hour. Stamping has been subject to extensive studies of mechanical properties and microstructure. The results of studies of the effect of temperature final stamping on the properties of titanium blanks in the following table and in Fig.1, 2 and 3. As can be seen from the table, the best mechanical properties were observed in preparations exposed final stamping in existencephase close to the temperature predpripravene who ate the strength of such forgings increased by 8-10%, and characteristics of plasticity in 1.5-2 times compared to forgings, deformed as inphase, and-phase, 30...70°C below the temperature of polymorphic transformation. In addition, there is stability, small spread and a smaller dependence of mechanical properties on the direction of testing of forgings, strain in thephase close to the temperature of polymorphicpredpriyatiya.
Heating and deformation of titanium billets in the temperature interval of existencephase close to the temperature polymorphic predpriyatiya(Fig.2) lead to the fact that the apparent grain boundaries of the originalphase is not observed, the structure is characterized by a plastic structure vnutrikabinnoe-phase with the transition to globular, i.e. obrazovannuju strength and ductility of titanium billets.
Heating and deformation of titanium billets in the temperature interval-phase (Fig.1) lead to the formation of lamellar (-transformed) patterns with distinct grains sourcephase borderedphase, andgrains consist of-colonies, which packs-plates, separated layers-phase. This structure defines the lower characteristics and strength and plasticity and significant instability.
Heating and deformation of titanium billets in the temperature interval of existencephase, but 30...70°With lower temperaturestransformation (Fig.3) leads to the escalation thickness-plates and the accumulation of deformation stresses that significantly reduces the strength and ductility of the metal and increases their volatility.
An example of a specific implementation.
Procurement of the same cast from an alloy VT20 in EY 1100-20°With a duration of 75+30 min and subjected to forging. After Stripping defects billet was heated to a temperature of 1000-20°C for 60+20 min and subjected to blanking and stamping. Then blanking stamping was heated to a temperature of 970°C for 40+10 min and subjected to final pressing and cooled in air.
After this stamping was annealed at 850°C for 1 hour to remove residual stresses and subjected to comprehensive studies on mechanical properties and microstructure. The research results are shown in table 2, and Fig.2.
The proposed method in comparison with analogues can improve the tensile strength of 8-10%, the characteristics of plasticity in 1,5-2 times, to reduce the anisotropy of the properties of forgings, depending on the direction of testing and improve the quality of parts.
The method of processing pseudo-titanium alloys, including multi-stage heating and stamping and subsequent cooling, and the heat under the final stamping produce to a temperature below the temperatureturning on the temperature not lower than 30°C temperaturetransformations and then spend annealing.
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.
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.