Method of hot rolling of thick sheets from copper alloys
SUBSTANCE: method includes heating of a flat stock and its multi-pass pressing in working rollers. Exclusion of formation of internal defects in rolled metal is achieved by the fact that heating of the stock is carried out to temperature of 750-850°C, and pressing in each of passes is regulated by mathematical dependence.
EFFECT: increased quality of thick-sheet rolled metal from hard-to-deform copper alloys with lower process plasticity.
1 tbl, 6 ex
The method of hot-rolled thick plates of copper alloy
The invention relates to rolling production and can be used to obtain thick sheets of hard copper alloys with low technological plasticity.
There is a method of rolling sheets of copper alloy comprising heating the ingot to a temperature of 820°C and subsequent multi-pass hot and cold rolling with a regulated reductions .
The disadvantage of this method is that during rolling of copper alloys with low technological plasticity in the leaves form the internal defects such as cracks and breaks that affects the quality of the products and reduces the yield.
The closest analogue of the present invention is a method of rolling thick sheets of copper alloys, including heat flat blanks, multipass hot rolling in the temperature range 780-450°C and subsequent cold rolling .
The disadvantages of this method are that when the rolling of thick sheets of copper alloys with low technological plasticity deformation produced by the working rolls is attenuated by the thickness of the blank and does not extend across the whole width. The uneven deformation in thickness leads to the formation in the Central layers of leaves cracks razryvov. This reduces the quality and yield of plates.
The technical problem solved by the present invention is to improve the quality and yield of thick sheets of copper alloys with low technological plasticity.
To solve the technical problem in the known method of hot-rolled thick plates of copper alloys, including heat flat blanks and multi-pass compression in the working rolls, according to the invention, the heating of the workpiece lead to a temperature of 750-850°C, and the compression in each of the passages set value:
where h0the thickness of the workpiece before the passage;
D - diameter work rolls;
f is the coefficient of external friction;
µ is the Poisson's ratio of the copper alloy at a temperature of deformation.
The invention consists in the following. In the process of hot rolling of flat blanks of copper alloy in plates under compression in each of the passages has an uneven strain on its thickness: deformation of m is ximala the contact surfaces of the workpiece, interacting with the working rolls, unevenly and quickly fades out to the middle of it, that does not preclude the formation of internal defects such as cracks and breaks.
In the course of the experiments was determined empirical dependence of the minimum allowable relative compression 8 on temperature and other parameters of rolling and properties of copper alloy, wherein during compression between the work rolls deformation guaranteed penetrates the entire thickness of the workpiece. Therefore, when the condition is met:
the rolling of thick sheets of copper alloys occurs without the formation of internal cracks and breaks. Specified experimentally definite correlation was obtained for the conditions of rolling copper alloys thickness 10-90 mm the Exception of the formation of internal defects, in turn, increased the yield of plates.
It is found experimentally that when the heating temperature above 850°C due to the oxidation of the grain boundaries of the copper alloy in the rolling process, the formation of trading the peal, which reduces the yield. Lowering the temperature below 750°C degrades the ductility of copper alloys and uniformity of deformation in thickness of the workpiece. It stimulates the formation of defects and leads to reduced yield.
Also experimentally found that when the relative compression for passage
deformation from the side of the work rolls does not cover the entire thickness of the flat blanks that leads to it internal defects and reduced yield.
Examples of implementation of the method
Cast flat workpiece thickness h0=100 mm of copper alloy grades BRB with chemical composition, wt.%:
heated in a gas furnace to a temperature of T=800°C, serves to reverse I Duo with a diameter steel work rolls D=700 mm For the reference data to determine the coefficient of external friction during hot rolling f=0.3 and Poisson's ratio of this copper alloy at a temperature deformation µ=0,5.
Calculate the parameters and0and a1:
then calculate the minimum value of the relative compression in the first pass, at which plastic deformation from the work rolls penetrates the entire thickness of the workpiece:
With the help of push mechanisms set mijalkovic gap and produce compression of a flat workpiece in the first aisle is of thickness h 0=100 mm and thickness h1=90 mm with a relative compression εfequal to:
Since the actual value of the relative compression εfexceeds the minimum value of ε, the plastic deformation from the upper and lower work rolls more evenly and penetrates the entire thickness of the flat blanks, which prevents the formation of cracks and breaks in its inner layers.
Similarly calculate εffor the second and subsequent passes, setting the actual compression in each of them in accordance with the ratio εf≥ε. Rolling carry out to obtain sheets with thickness of 20 mm.
Due to the fact that in each of the passages of the plastic deformation from the rolls penetrates the entire thickness of the rolled blank is uniform, no formation of cracks and breaks in its inner layers, the yield of thick sheets of hard copper alloys increases and reaches the value Q=99,7%.
Options real is the organization of the proposed method and the indicators of efficiency listed in the table.
From the data given in the table, it follows that if implementation of the proposed method (options No. 2-4) are excluded education in a thick sheet of copper alloy internal cracks and breaks, resulting in increasing the yield of metal.
|Modes hot-rolled copper alloy brand BRB and the yield|
|№ p/p||T, °C||ε||Internal defects||Q %|
|6.||700||not regulated||cracks, breaks||75,3|
With exorbitant values of the declared options (options # 1 and # 5), and the implementation of the known method (option # 6) is the formation of cracks and breaks in the plate rolled from hard copper alloys with low technological plasticity, which, in turn, leads to reduced yield.
Technical appraisal and economic benefits of the proposed method consist in the fact that heating the billet to a temperature of 750-850°C and subsequent compression in each of the aisles not less than the value specified on experimentally determined value, provides the penetration of plastic deformation and its uniform distribution throughout the thickness of the sheet. Because of this, as the test showed, is improving the quality and yield of thick sheets of copper alloys with low technological plasticity.
As the base object is accepted, the closest analogue. The use of the proposed JV is soba increase profitability sheets of a thickness of 8-50 mm made of hard copper alloys by 25-35%.
Sources of information
1. Berman, S. Copper-Bellevue alloys, their properties, applications and processing. M.: metallurgy, 1966, s, 254.
2. The patent of Russian Federation №2223157, IPC B21B 3/00, 2004
The method of hot-rolled thick plates of copper alloys, including heat flat blanks of copper alloy and multi-pass compression in the working rolls, characterized in that the heating of the workpiece lead to a temperature of 750-850°C, and the compression in each of the passages set by the ratio:
where h0the thickness of the workpiece before passage, mm.
D - diameter work rolls, mm;
f is the coefficient of external friction;
µ is the Poisson's ratio of the copper alloy billet at a temperature of deformation.
SUBSTANCE: in compliance with proposed method of rolling thin bands from aluminium Al-Mg or Al-Mg-Mn system alloys fully recrystallised hot-rolled band blank is subjected to rolling. Band blank features cubic texture and depth 9-10 times larger than band final depth. Rolling causes 45-47% reduction at every of two last passes at deformation rate of at least 10 m/s and band coiling temperature of 140-160°C, coil weight making at least 8 t.
EFFECT: higher metal ductility, decreased scatter of mechanical properties.
SUBSTANCE: proposed method comprises hot forming of slab, hot rolling and teat treatment of plate, whereat hot forming if carried out in one step. Immediately after reaching required thickness in slab forming it is quickly cooled to the depth of 20-30 mm at the rate of at least 50°C/min. Subsequent hot lengthwise rolling at performed at first step in α+β-area by partial reduction with deformation degree εi varying from 3% to 5% to total deformation ε=25…30% with breaks between passes of 8 to 12 s. At second step, it is performed in β-area from heating temperature determined by definite formula. At the next step rolling is performed in α+β-are with breaks and heating in lengthwise or transverse directions with total degree of deformation e after every break to 60%.
EFFECT: homogeneous fine-grain microstructure, high and stable mechanical properties, high precision, no surface defects.
SUBSTANCE: invention relates to production of thin sheets from ingot of pseudo-alpha titanium alloy. Proposed method comprises forming ingot of alloy Ti-6.5Al-2.5Sn-4Zr-1Nb-0.7Mo-0.15Si into slab and machining of the latter. Then, said slab is heated to temperature exceeding that of polymorphic transition, deformation and multistep rolling to semi-finished rolled stock with regulated total degree of deformation and degree of deformation in a pass. Sheets are stacked, stacks are rolled to finished size and subjected to multipass rolling with regulated total deformation, sheets are extracted from the stack and subjected to finishing.
EFFECT: high and uniform strength and plastic properties.
1 dwg, 2 tbl
SUBSTANCE: proposed method comprises smelting of alloy, making slab, machining its surface, hot, warm, and cold rolling, sintering and ageing. Smelted is pseudo-beta-titanium alloy with aluminium content not higher than 5.0 wt % and molybdenum equivalent No eq. ≥ 12 wt %, calculated by the following formula: Mo eq. wt % = %Mo + %Ta/4 + %Nb/3.3 + %W/2 + %V/1.4 + %Cr/0.6 + +%Fe/0.5 + %Ni/0.8 + %Mn/0.6 + %Co/0.9. Semi-finished 8-2 mm-thick rolled stock produced in hot and cold rolling is subjected, prior to cold rolling, to quenching at Tpt+(20-50°C) for 0.1-0.5 h with cooling. Cold rolling is performed to sheet thickness of 6-1 mm in signal-phase beta-state in two and more steps in several passes with 1-6%-reduction in one pass and total reduction at every step of 30-50%. Note here that intermediate quenching is carried out between said steps in conditions identical to quenching of semi-finished rolled stock before cold rolling.
EFFECT: high-quality rolled thin sheets.
5 dwg, 2 tbl
FIELD: process engineering.
SUBSTANCE: invention is intended for increasing quality of sheets and ruling out pollution originating in forming special magnesium alloys doped with high-toxicity light-volatile elements that form, in heating and forming, harmful oxides, and may be used in production of sheets for anodes of electrochemical current sources. Proposed method comprises placing round ingot in tubular shell, hearing the workpiece and its hot and warm rolling to requited sheet thickness.
EFFECT: higher quality of sheets and process efficiency.
FIELD: process engineering.
SUBSTANCE: invention relates to metallurgy, particularly, to forming semis from titanium alloy BT6 and may be used in machine building, aircraft engineering and medicine. Proposed method comprises annealing at 850°C with holding for an hour in furnace to create globular (α+β)-structure and multipass rolling combined with affecting semis to pulsed electric current with density of 50-200 A/mm2, frequency of 830-1000 Hz, pulse duration of 100-120 ms to ensure total true strain degree of e>1 and to form nanocrystalline structure in semi. Note that, after every pass, semi is water cooled. Higher forming capacity of alloy is provided for.
EFFECT: higher strength at optimum ductility.
5 cl, 1 dwg, 1 tbl, 1 ex
FIELD: process engineering.
SUBSTANCE: proposed method comprises making ingots or powder billets. The latter are subjected to hot thermo mechanical machining, including sandwich rolling and finish cold rolling. Foil material mechanical properties are stabilised and material structure is blended in sandwich rolling at semi-finished rolled stock thickness of 2-4 mm with premade fine structure wherein grain width does not exceed 10 mcm while its length makes 40 mcm. Sandwich is composed of a set of semi-finished rolled billet and two steel covering plates. Note here that top covering plate thickness is 1.4-1.8 times larger than that of bottom plate. Hot rolling of sandwich is started from 950±50°C in several passes with total deformation of 70-90%. After annealing at 920±70°C and sandwich disassembly, cold rolling of every billet is performed at total deformation of 40-70% with intermediate vacuum annealing at 920±70°C.
EFFECT: higher foil quality made from titanium aluminide-based alloys based on Ti2AlNb orthorhombic phase.
2 cl, 4 dwg, 2 tbl
FIELD: process engineering.
SUBSTANCE: proposed method comprises stage-by-stage grinding of titanium billet grains by abc-forming and multi-pass rolling in grooved rolls with stepwise reduction in groove section at fixed temperature of billet heating for rolling. Increased mechanical properties are ensured by stepwise grain grinding at stepwise temperature reduction in the range of 750-500°C. In abc-forming, titanium billets made be subjected to recrystallisation annealing at 680-700°C for 1 h. Rolling in grooved rolls is performed at reducing billet temperature by 40-60°C at every pass to groove smaller section from 500°C to 300°C whereat rod final round cross-section is formed. The number of groove cross-sections id selected to provided for reduction not exceeding 40% in transition from one groove to another. Rolling is performed in several passes on turning the billet through 90 degrees about lengthwise axis. 4-8 mm-dia round titanium billets are produced to meet high purity standards.
EFFECT: higher metal yield.
6 cl, 2 tbl, 3 ex
SUBSTANCE: method to manufacture cold-deformed pipes from double-phase alloys based on titanium includes ingot smelting, ingot forging in a β-area or β- and α+β-area with forging completion in the α+β-area into an intermediate blank with the specified forging reduction. The intermediate blank is produced with forging reduction of at least 1.35, a block is made from the intermediate blank, which is pressed into a billet and thermally treated at the temperature that is by 30°-40°C below the temperature of Tint, and them the billet is rolled with intermediate surface treatment, etching and thermal treatment. Drawing in process of rolling is defined using the following formula.
EFFECT: produced pipes are characterised by high physical-mechanical properties due to exclusion of formation of grain-to-grain microcracks.
4 tbl, 1 ex
FIELD: process engineering.
SUBSTANCE: invention is intended for making high-strength rolled sheet from aluminium alloys. Proposed method comprises making flat billet and lengthwise cold rolling to target thickness. Note here that cold rolling is performed at -80 to -196°C with total reduction of 35-99%. After rolling to thickness exceeding target thickness by 2.8-9.5 times, billet is turned through 90 degrees in rolling plane.
EFFECT: higher strength and toughness.
2 cl, 1 tbl
FIELD: plastic working of metals, possibly manufacture of thin high-strength foil of titanium.
SUBSTANCE: method comprises steps of multi-pass reversing cold rolling and vacuum annealing; repeating cycle; using as initial blank titanium blank with ultra-fine grain structure provided due to intensified plastic deformation by equal-duct angular pressing process; rolling at pitch 15 - 8% for achieving total deformation 70 - 86 % per one cycle; setting number N of cycles necessary for making foil with thickness h according to mathematical expression; realizing vacuum annealing, preferably at temperature 350 -360 C for 0.5 - 1 h. Invention provides possibilities for making titanium foil with thickness up to 10 micrometers.
EFFECT: enhanced strength characteristics of titanium foil of lowered thickness with the same technological platicity7777.
2 cl, 2 tbl
FIELD: metallurgy, processes for making hot rolled band of magnesium alloy.
SUBSTANCE: method comprises steps of producing strip blank by continuous casting of melt of magnesium alloy; hot rolling of strip blank directly after casting at several passes for producing hot rolled band with thickness no more than 50 mm. Hot rolling is performed at initial temperature values 250°C - 500°C for providing final thickness of band no more than 4 mm. At first pass of hot rolling reduction degree is equal at least to 15%.
EFFECT: possibility for making magnesium sheets with improved deformation capability at less costs of manufacturing process.
11 cl, 1 dwg, 2 tbl, 1 ex
FIELD: plastic working of special magnesium base alloys alloyed with elements capable to easy evaporation or to generation at deformation oxides hazard for environment, possibly manufacture of rolled sheets used for making anodes of electrochemical current sources.
SUBSTANCE: method comprises steps of preliminarily deforming heated blank of magnesium base alloy and warm rolling of preliminarily deformed blank for producing sheet; before preliminary deformation placing magnesium alloy blank into envelope of aluminum (Al-Mg-Si system) alloy without sealing. Length of envelope exceeds length of blank at least by 10%. Preliminary deformation is realized by hot rolling or upsetting in die set according to configuration of blank.
EFFECT: production of sheets with electrochemical properties uniform along the whole cross section and with enhanced surface quality, safety labor condition due to preventing evaporation of mercury, toxic oxides and other compounds containing mercury, thallium, gallium, cadmium.
12 cl, 4 tbl, 4 ex
FIELD: metallurgy; plastic metal working; production of strips from aluminum alloys.
SUBSTANCE: proposed method includes multi-pass hot rolling and final rolling; last pass of multi-pass hot rolling is performed at rate of deformation of 60-150 1/s and degree of deformation of 35-60% at temperature of Trec.+30 to Trec.; after multi-pass hot rolling, metal is subjected to relaxation holding at temperature range of Trec.+30 to Trec. continued for 2-50 min; said rate of deformation, degree of deformation and temperature of last pass of hot rolling, as well as temperature and time of last relaxation holding ensure completeness of spontaneous recrystallization; final rolling is performed at degree of deformation of 30-75% at temperature range of from Trec.-100 to Trec.-150, where Trec. is recrystallization temperature; then, roll is cooled in air. Ingots of mass no less than 5 t may be subjected to multi-pass hot rolling.
EFFECT: improved quality of metal possessing low anisotropy and enhanced mechanical properties.
2 cl, 1 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: rolling processes and equipment, namely manufacture of armor sheets and plates of aluminum base alloys used in aircraft- and ship manufacture, for making armored transport vehicles and so on.
SUBSTANCE: method for making armor sheets and plates of aluminum base Al-Mg-Mn alloys with Mg content no less than 4 mass % comprises steps of hot rolling of ingot to plate and finish rolling of it; performing as finish rolling warm rolling at temperature 80 - 300°C with total deformation degree no less than 60%; preferably realizing warm rolling at temperature 250 - 290°C with total deformation degree 65 - 80%. Invention provides ballistic protection degree 738 - 742 m/s for plates with thickness 38.0 -38.2 mm at firing on with armor-piercing shells 7.62.
EFFECT: improved resistance against ballistic action due to constant strength and ductility values at high corrosion resistance, good welding capability and small mass.
4 cl, 3 dwg, 2 tbl, 2 ex
FIELD: plastic metal working.
SUBSTANCE: invention is designed for manufacturing of flat sections from zirconium-niobium alloys for use as structural materials of active zone in nuclear reactors. Proposed method includes forging of ingot of zirconium-niobium alloys, hot rolling with heating in α+β-area, cold rolling with intermediate and vacuum thermal treatments. Hot rolling is carried out at one stage of heating with integral value of deformation 1nμ.2.5 and partial reductions per pass of 1nμ≤0.32 or at two heating stages at summary deformation of 1nμ≤2.8. In some cases, prior to one of hot rolling stages, hardening of semifinished products is carried out from area of existence of β-zirconium. Invention guarantees mechanical properties of structural members for active of nuclear reactors at height technical and economical characteristics of production of flat sections from zirconium-niobium alloys featuring form-changing capabilities.
EFFECT: improved economy and homogeneity of mechanical properties of rolled product.
2 cl, 2 ex, 1 tbl
FIELD: tube rolling of α and (α +β) titanium -base alloys.
SUBSTANCE: process comprises steps of forging ingot to blank; working blank; making central opening in it. Rolling blank in pilger mill and subjecting it to mechanical working. At each transition forging is started at temperature of β-range or at temperature of β- and (α +β ) range , as cooling blank, forging is ended in (α +β) range at forging reduction ratio no less than 20%. Through piercing of solid blank is realized at temperature in β-range. Before rolling in pilger mill pierced blank is cooled till temperature that is by 30 -100 C less than Tpr. Rolling process is performed at deformation rate (3 x 10-1 s-1 )- (102 s-1 ).
EFFECT: possibility for making tubes with fine-grain highly uniform microstructure.
1 cl, 2 ex
FIELD: metallurgy, possibly manufacture of semi-finished products such as rods and tubes of hyper-eutectic Silumins.
SUBSTANCE: method comprises steps of casting ingots; homogenizing it and subjecting to helical rolling for making rod; piercing rod for making tube. Rolling process is realized at axial end push effort while reducing blank between cone cross section rolls. Rolling speed, end push effort, length of sizing zone and inter-roll gap are normalized.
EFFECT: enhanced ductility of metal.
2 cl, 1 ex, 1 tbl
FIELD: metallurgy; production of superconducting wires operating at temperature of liquid helium in magnetic systems of charged-particle accelerators.
SUBSTANCE: proposed method includes homogenizing annealing of ingot within temperature interval of from 1200 to 1350°C and application of protective copper coat on ingot. Then, ingot is heated to temperature of 800-900°C and is subjected to extrusion deformation for obtaining first billet which is subjected to machining followed by application of protective copper coat. First billet is heated at temperature of 800-900°C and is subjected to extrusion deformation for obtaining second billet which is also subjected to machining. Then, the following operations are performed: re-crystallization annealing at temperature of from 950 to 1250°C, cold rolling to preset size of billet and re-crystallization annealing at temperature of from 950 to 1250°C. Billets thus produced possess property for further deformation at total drawing of up to 9·108 for production of superconductors.
EFFECT: enhanced efficiency; avoidance of undesirable diffusion processes.
7 cl, 3 ex