Method to produce axisymmetric forgings of cover type with diameter up to 200 mm from high-strength aluminium alloys al - zn - mg - cu, alloyed by scandium and zirconium

FIELD: metallurgy.

SUBSTANCE: method to produce axisymmetric forgings of a cover type with a diameter of up to 200 mm from high-strength aluminium alloys Al-Zn-Mg-Cu, alloyed with scandium and zirconium, includes preparation of aluminium melt, containing scandium and zirconium, its reheating to 765-780°C, casting of round bars of small diameter at 710-740°C, their homogenisation at 400-440°C for 4-10 hours, stamping at 380-440°C, tempering from temperature 465-480°C with even cooling of the entire surface of forgings with speed providing for preservation of fully non-crystallised structure of the forging after tempering, and artificial ageing.

EFFECT: forgings have lower level of residual tempering stresses, which provides for stability of geometric parameters of parts due to elimination of ovalisation when turning forgings into thin-walled parts.

2 tbl, 1 ex

 

The present invention relates to the field of metallurgy, in particular to methods for production of forgings of high strength aluminum alloys of Al-Zn-Mg-Cu doped with scandium and zirconium.

Well-known classical method for the production of small forgings, aluminum alloy, which consists in the continuous casting method of the round bars, homogenization, extrusion of the rods with the subsequent stamping of these parts, quenching and artificial aging. Sometimes the purpose of simplification of the technological scheme of production of small forgings (200-mm diameter) as blanks for stamping use bars of small diameter (Aluminum alloys. Melting and casting of aluminum alloys: a reference guide. - M.: metallurgy, 1983. - S-158.; Production of semi-finished products of aluminium alloys: reference guide - M.: metallurgy, 1971 - S-404). Similar.

The disadvantage of this method of production of forgings made of high-strength alloys of Al-Zn-Mg-Cu doped with scandium and zirconium, is the sharp decrease of the strength characteristics of the finished heat-hardened forgings (20-25%).

Known technological scheme and the specific value of a process (temperature and time) of the parameters used in the production of rolled semi-finished products from aluminum alloys doped with scandium and what Iconium (Berezin L.G., Petrenkov P.P. Development of technology for manufacturing sheets from alloy 01570 width 2000-2500 mm // Technology of light alloys. - 1991. No. 1. - P.32-37), the use of which in the production of forgings of alloy Al-Zn-Mg-Cu doped with scandium and zirconium, gives you the opportunity to get stamping with higher strength characteristics. The prototype.

Received stamping by known techniques have a higher strength characteristics than using technology similar. However, the full strength potential, inherent nature alloys of Al-Zn-Mg-Cu with additions of Sc and Zr, is not implemented. The level of strength properties of thermally hardened forgings reduced by 8-10% compared to the actually possible.

We propose a method of production of an axisymmetric closed die forgings type cap with a diameter up to 200 mm made of high-strength alloys of Al-Zn-Mg-Cu doped with scandium and zirconium, comprising preparing an aluminum melt containing scandium and zirconium, overheating to 765-780°C, casting round ingots of small diameter when 710-740°C, homogenization at 400-440°C for 4-10 hours, stamping at 380-440°C, quenching with temperature 465-480°C with a uniform cooling of the entire surface of the blanking speed, ensuring the preservation after quenching fully precrystallization patterns stamping, and artificial aging is s.

The proposed method of production of an axisymmetric closed die forgings type cap with a diameter up to 200 mm made of high-strength aluminum alloys of Al-Zn-Mg-Cu doped with scandium and zirconium, differs from the known fact that overheating of the aluminum melt containing scandium and zirconium, is carried out at 765-780°C, the homogenization of the cast ingot is carried out at 400-440°C for 4-10 hours, quenching is performed with temperature 465-480°C with a uniform cooling of the entire surface of the blanking speed, ensuring the preservation after quenching fully precrystallization patterns stamping, and artificial aging.

Using the proposed method allows to obtain the axisymmetric forging diameter up to 200 mm made of high-strength alloys of Al-Zn-Mg-Cu doped with scandium and zirconium, in the quenched and artificially aged condition with high strength properties.

Mentioned stamping are mainly used in the nuclear industry in the production of the corresponding destination, and they place high demands on the level of strength properties.

Example

The continuous casting method using an electric furnace with a capacity of 180 kg two were cast ingot with a diameter of 92 mm weight 90 kg the following chemical composition (table 1).

Table 1
The actual chemical composition of cast ingots of the alloy Al-Zn-Mg-Cu-doped scandium and zirconium, wt.%
AlZnMgCuScZrBeFeNiCoSi
Base7,13,61,10,210,110,0020,450,520,110,17

The ingots are homogenized and grind the workpiece under stamping with a diameter of 80×60 mm, of which the method of the inverse extrusion was obtained plate-punching diameter 146 mm with wall thickness of 20 mm on known and proposed methods.

The known method (prototype).

When conducting melting by a known method, the aluminum melt containing scandium, zirconium and cobalt overheated up to 750°C, kept at this temperature for 1 hour, positively other alloying comp the components (zinc, magnesium, copper and others) and at a temperature of 715°C was carried out by the casting of the ingot. The ingot is homogenized by mode 380°C, 8 h, were processed into blanks and stamped on the cover, which was tempered in water with a temperature of 470°C, artificially aged very early because 140°C, 16 h, and tested for tensile strength in Cordova and radial directions.

The proposed method.

Aluminum melt containing scandium, zirconium, cobalt, overheated up to 775°C, kept for 1 hour, positively alloying elements (zinc, magnesium, copper and others) and at a temperature of 730°C was carried out by the casting of the ingot. The ingot is homogenized by mode 430°C, 8 h, were processed into blanks and stamped on the cover, which was then tempered in water to 470°C. the quenching Conditions were chosen experimentally. Cover-forming installed vertically in a staggered manner in a specially designed quench the basket with the distance between the die 40 mm of Water was heated to 60°C and during the quenching process was carried out intensive bubbling water using regulated compressed air from the bottom of the quenching tank. After quenching stamping aged very early because the mode 140°C, 16 hours

Table 2 presents the results of a study of pilot batches of blanks produced by a known method and the proposed method.

Table 2
The results of the study forgings obtained by the known and proposed methods
The method of obtaining stampingThe direction of the cut sampleMechanical properties
St, MPaσof 0.2, MPaδ, %
KnownChordal6175836,7
Radial6155816,5
OfferChordal6746375,1
Radial6756394,8

Examination of table 2 shows that the proposed method of producing forgings of alloy Al-Zn-Mg-Cu with additions of Sc and Zr allows you to get stamping with higher strength characteristics. The reason for the achievement Boliviana strength alloys using the proposed method, is that punching in this case keep after quenching fully precrystallization structure, while the structure of blanks obtained by a known method, partially recrystallized. In addition, in the structure of blanks obtained by a known method, there are large intermetallic compounds of Al3(Sc, Zr) (10 μm), negatively affecting the mechanical properties.

Method for the production of axisymmetric forging type cap with a diameter up to 200 mm made of high-strength aluminum alloys of Al-Zn-Mg-Cu doped with scandium and zirconium, comprising preparing an aluminum melt containing scandium and zirconium, overheating to 765-780°C, casting round ingots of small diameter when 710-740°C, homogenization at 400-440°C for 4-10 hours, stamping at 380-440°C, quenching with temperature 465-480°C with a uniform cooling of the entire surface of the blanking speed, ensuring the preservation after quenching fully precrystallization patterns stamping, and artificial aging.



 

Same patents:

FIELD: metallurgy.

SUBSTANCE: proposed method comprises casting the ingots of alloy containing the following components in wt %: zinc - 6.-4.1, magnesium - 0.6-1.1, manganese - 0.2-0.5, zirconium - 0.05-0.12, chromium - 0.05-0.15, copper - 0.1 -0.2, titanium - 0.01 -0.06, molybdenum - 0.01 -0.06, aluminium making the rest, at the temperature of 690-710°C and casting rate of 25-50 mm/min. Ingots are homogenised at 450-470°C for 8-12 hours and subjected to hot forming at 10-530°C and outflow rate of 0.1-4.0 m/min. Besides it includes air or air-water mix quenching and two-step ageing: at 90-110°C for 6-12 hours and at 160-190°C for 4-10 hours.

EFFECT: production of log parts with high operating properties.

4 cl, 1 ex, 6 tbl, 4 dwg

FIELD: metallurgy.

SUBSTANCE: alloy contains, wt %: 3.5-4.5 zinc, 3.5-4.5 magnesium, 0.6-1.0 copper, 2.0-3.0 nickel, 0.25-0.3 zirconium, aluminium - balance, at the same time after strengthening thermal treatment the alloy has yield point of 570 MPa, strength limit of 600 MPa, hardness of 160 HY, and after deformation at 440-480°C with speed of 0.001-0.01 1/s the alloy has elongation of more than 500%.

EFFECT: production of alloy with equiaxial homogeneous fine-grain structure.

4 ex

FIELD: process engineering.

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EFFECT: high strength and precision.

1 dwg, 1 tbl

FIELD: metallurgy.

SUBSTANCE: method includes homogenisation of a bar, heating to 360-450°C, hot rolling, cold rolling with extent of deformation of 45-70% and intermediate annealing, and final thermal treatment, including three-stage artificial ageing according to the following mode: first stage at 80-125°C for 8- 24 hr, second stage at 130-180°C for 4-30 hr and third stage at 145-180°C for 2-18 hr or double-stage ageing, including the first and second, or the second or third, or the first or third stages.

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3 cl, 5 ex, 8 tbl, 1 dwg

FIELD: metallurgy.

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EFFECT: higher strength, lower residual strain.

11 cl, 4 ex

FIELD: metallurgy.

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EFFECT: high strength, low sensitivity to quenching.

12 cl, 8 dwg, 6 tbl, 2 ex

FIELD: weapons and ammunition.

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EFFECT: improving armour properties and durability of sandwich plate.

5 cl, 1 tbl

FIELD: metallurgy.

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30 cl, 8 tbl, 3 ex

FIELD: metallurgy.

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where T corresponds to instant temperature in K during annealing, while Tcontr corresponds to control temperature equal to 302°F (423K), and t(eq) is expressed in hours.

EFFECT: production of deformed product possessing improved combination of mechanical strength for corresponding level of crack resistance and resistance to corrosion cracking under load.

8 cl, 2 dwg, 10 tbl, 4 ex

FIELD: metallurgy.

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32 cl, 6 tbl, 6 ex

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2 cl, 1 ex, 2 tbl

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4 cl, 2 tbl, 10 dwg, 2 ex

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EFFECT: high hardness, ductility and lower sensitive to quenching.

20 cl, 2 tbl, 1 ex

FIELD: metallurgy.

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EFFECT: higher strength at sufficient ductility and reduce density of alloy.

1 ex, 3 tbl

FIELD: metallurgy.

SUBSTANCE: proposed method comprises casting the ingots of alloy containing the following components in wt %: zinc - 6.-4.1, magnesium - 0.6-1.1, manganese - 0.2-0.5, zirconium - 0.05-0.12, chromium - 0.05-0.15, copper - 0.1 -0.2, titanium - 0.01 -0.06, molybdenum - 0.01 -0.06, aluminium making the rest, at the temperature of 690-710°C and casting rate of 25-50 mm/min. Ingots are homogenised at 450-470°C for 8-12 hours and subjected to hot forming at 10-530°C and outflow rate of 0.1-4.0 m/min. Besides it includes air or air-water mix quenching and two-step ageing: at 90-110°C for 6-12 hours and at 160-190°C for 4-10 hours.

EFFECT: production of log parts with high operating properties.

4 cl, 1 ex, 6 tbl, 4 dwg

FIELD: metallurgy.

SUBSTANCE: alloy contains, wt %: 3.5-4.5 zinc, 3.5-4.5 magnesium, 0.6-1.0 copper, 2.0-3.0 nickel, 0.25-0.3 zirconium, aluminium - balance, at the same time after strengthening thermal treatment the alloy has yield point of 570 MPa, strength limit of 600 MPa, hardness of 160 HY, and after deformation at 440-480°C with speed of 0.001-0.01 1/s the alloy has elongation of more than 500%.

EFFECT: production of alloy with equiaxial homogeneous fine-grain structure.

4 ex

FIELD: metallurgy.

SUBSTANCE: alloy contains the following, wt %: silicon 6.6-7.4, magnesium 0.31-0.45, copper 0.18-0.32, manganese 0.15-0.45, iron 0.15-0.4, aluminium is the rest, at that, the alloy has liquidus temperature within 608 to 620°C; temperature of balanced solidus of not less than 552°C and structure after heat treatment as per mode T66, which contains the amount of inclusions of silicon phase within 6.4 to 7.5 vol. %; iron in the alloy structure is completely bound to skeletal inclusions of phase Al15(Fe,Mn)3Si2, and magnesium is completely bound to secondary extractions of phase Al15Cu2Mg8Si6.

EFFECT: creation of alloy for obtaining high-duty shaped castings and having high technological and operating characteristics.

2 cl, 2 tbl, 2 ex, 2 dwg

FIELD: metallurgy.

SUBSTANCE: proposed composition contains the following substances, in wt %: zinc - 5.0-5.8, magnesium - 1.1-1.2, chromium - 0.2-0.3, copper - 0.1-0.4, titanium - 0.05-0.15, cerium - 0.005-0.05, samarium - 0.005-0.05, silicon - not over 0.3, iron - not over 0.3, zirconium - not over 0.005, aluminium making the rest. Method of making semis from said aluminium alloy comprises first thermal treatment at up to 480°C, cooling to room temperature, and second thermal treatment at up to 200°C.

EFFECT: higher strength, lower residual strain.

11 cl, 4 ex

FIELD: metallurgy.

SUBSTANCE: invention may be used for making critical parts operated at high loads at 150°C, e.g, those of aircraft, cars and trucks, etc. Proposed composition contains the following substances, in wt %: 5.5-6.5 Zn, 1.7-2.3 Mg, 0.4-0.7 Ni, 0.3-0.7 Fe, 0.02-0.25 Zr, 0.05-0.3 Cu. Its solvus temperature does not exceed 410°C while hardness makes, at least 150 HV.

EFFECT: higher strength and machinability.

3 cl, 3 tbl, 3 ex, 2 dwg

FIELD: metallurgy.

SUBSTANCE: proposed composition contains the following substances, in wt %: zinc - 4-5, indium - 0.01-0.1, zirconium - 0.01-0.1, titanium - 0.02-0.1, aluminium and impurities making the rest. Content of impurities in the alloy of iron, silicon and copper may no exceed 0.1, 0.1 and 0.01, respectively, while that of hydrogen must no exceed 0.20 cm3/100 g Me.

EFFECT: higher efficiency and stability of electrochemical characteristics.

2 cl, 3 tbl

FIELD: weapons and ammunition.

SUBSTANCE: method involves performance of cuts along outer surface of a rod of rolled product and piercing of a workpiece with simultaneous drawing. Cuts are made at the specified distance from each other to diameter of the obtained hole.

EFFECT: reduction of metal scrap.

1 dwg

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