RU2158318C1 - High-damping alloy based on iron with controlled level of damping and mechanical properties and product made on high-damping alloy - Google Patents

Abstract

FIELD: metallurgy, particularly, high-damping alloys based on iron-aluminum system and products made of these alloys; applicable in manufacture of cold- and hot-rolled sheets, bars, rods and forgings used as structural materials, and manufacture of structural members and fasteners. SUBSTANCE: high- damping alloy with controlled level of damping and mechanical properties contains carbon, aluminum, manganese, titanium, copper and niobium with the following amounts of components, wt.%: carbon 0.010- 0.035; aluminum 4.0-8.0; manganese 0.25-0.95; niobium 0.01-0.15; copper 0.01-0.20; the balance, iron. Total content of carbon and copper is determined by relationship σ_0,3 and σ_h(SC+1.5Cu)= 0.06-0.45% and contents of aluminum, manganese, titanium and copper are related by relationship, in this case Al-Σ(Mn+Ti+Cu)= 3.5-6.5. EFFECT: improved mechanical properties (Σ) of high-damping alloy and products made of it with preserved high level of damping properties. 2 cl, 2 ex

Description

The invention relates to the field of metallurgy, in particular to high damping alloys based on the iron-aluminum system, as well as to products made from them, and can be used in the manufacture of cold and hot rolled sheets, long products, bars and forgings used as structural materials, as well as in the manufacture of structural elements and fasteners. Known high-strength damping alloy based on iron (EP 0495121B1, MKI C 22 C 38/06, 1991), containing aluminum, silicon, manganese, not more than 0.01 wt.% Carbon (hereinafter referred to as wt.%) , not more than 0.01% nitrogen, not more than 0.01% oxygen, not more than 0.01% phosphorus, not more than 0.01% sulfur, more than 0.5% silicon, and to achieve high vibration damping properties, the ratio of aluminum concentrations and silicon in the alloy must be such that it satisfies the region of optimal concentrations in the ternary diagram of iron-aluminum-silicon, limited straight lines connecting the following points in series: A4 (7.05% aluminum, 0.95% silicon), B4 (6.50% aluminum, 1.10% silicon), C4 (4.70% aluminum, 2.75% silicon), D4 (2.25% aluminum, 2.45% silicon), E4 (1.00% aluminum, 3.60% silicon), F4 (1.00% aluminum, 0.50% silicon and more), G4 (7.50% aluminum, 0.50% silicon or more) and A4, and the manganese content in the alloy should be at least 0.1% and no more than the sum of the concentrations of aluminum and silicon. After annealing at a temperature of 1050 ^o C in vacuum, this alloy has the following mechanical and vibration-absorbing properties: tensile strength σ _in = 420 - 700 MPa, the level of internal friction Q ^-1 = 0.2-2.0% (which is equivalent when translation into units of the logarithmic decrement of vibrations in accordance with generally accepted methods in the world, level δ = 0.6-6.0% [Yu. K. Favstov, Yu.N. Shulga, AG Rakhstadt, Metallurgy of highly damping alloys. M. , Metallurgy, 1980; James DW, High damping alloys for engineering application., Mater. Sci. Eng., 1969, No. 4, pp. 1-8]). The disadvantage of this alloy is the insufficiently high level of deffining properties.

Known steel having high vibration damping properties and good weldability ([EP] 0540792A1, MKI C 22 C 38/06, 1991), containing not more than 0.02% carbon, not more than 0.02% silicon, not more than 0, 08% manganese, from 0.05 to 1.5% copper, from 1.0 to 7.0% aluminum, not more than 0.008% nitrogen, from 0.05 to 1.5% nickel. After hot rolling on sheets with a thickness of 25 mm and annealing at a temperature of 575 ^o C, this steel has the following level of damping and mechanical properties: internal friction Q ^-1 = 1.2-2.0% (which corresponds to δ = 4.0-6, 5%), yield strength σ _0,2 = 340-450 MPa, a tensile strength σ _B = 420 - 570 MPa, elongation Δ = 26-33%. The disadvantages of this alloy are not sufficiently high damping and insufficiently high strength characteristics.

Known products in the form of cold-rolled sheets with a thickness of 0.8 and 2.0 mm, used for the manufacture of structural elements from a damping alloy based on iron in accordance with (EP) 0495123 A1 (MKI C 22 C 38/06, 1991). The products are made of an alloy containing aluminum and silicon in the form of the main alloying elements, and to achieve high vibration damping properties, the ratio of aluminum and silicon concentrations in the alloy must be such that it satisfies the optimal concentration range in the triple iron-aluminum-silicon diagram bounded by straight lines connecting the following points in series: A4 (7.05% aluminum, 0.95% silicon), B4 (6.50% aluminum, 1.10% silicon), C4 (4.70% aluminum, 2.75% silicon) , D4 (2.25% aluminum, 2.45% silicon), E4 (0% aluminum, 4.50% silicon, AO ( 0% aluminum, 0% silicon), BO (8.00% aluminum, 0% silicon) and A4, while the content of manganese in the alloy should not be less than 0.1%, and the concentration of elements such as carbon, nitrogen, oxygen , phosphorus and sulfur should not exceed 0.01%. After rolling the product was annealed at a temperature of 1050 ^o C, and the level of internal friction of the material was Q ^-1 = 0.4-2.1% (which corresponds to the level δ = 1.2 -6.6%). The disadvantage of this alloy and products from it are sharp restrictions on the carbon content (not more than 0.01 wt.%), Which determines significant technological difficulties at metallurgical alloy production and, consequently, high cost of the alloy and articles thereof.

Known products made of iron-based alloys containing aluminum (2%), chromium (5%) and carbon (not more than 0.01%) in the form of flat parts measuring 50x50x4 mm and used to reduce sound emission during impact loading made of these alloys of parts by increasing the damping ability of the alloys by special heat treatment of products with repeated heating to temperatures of ~ 1100 ^o C (USSR patent 1161573A description, MKI C 21 D 8/00, 1985). The use of these products allows to reduce by 5-16 decibels the total level of sound pressure arising from shock loading of structural parts. The disadvantage of these products is their high cost due to the increased chromium content in the alloy.

Closest to the invention in technical essence and the achieved result is a known alloy of high damping of the following composition, wt.%:
Carbon - 01 - 0.1
Aluminum - 4.0 - 12.0
Manganese - 0.3 - 3.0
Titanium - 0.010 - 1.0
Iron - Else
wherein [Al- Σ (Mn + Ti)] = 3.5-8.5%, as well as products made from it (RF patent N 2005804, MKI C 22 C 38/14, publ. BI 1994 N 1, prototype alloy and product).

Products in the form of plates with a thickness of 1.5 mm made of this alloy, after cold deformation and heat treatment, have the following damping and mechanical properties: logarithmic decrement of oscillations δ = 25 - 30%, conditional yield strength σ _0.2 = 260 - 300 MPa, tensile strength σ _in = 430 - 500 MPa.

 The disadvantage of this alloy and products made from it is not a high level of mechanical properties.

 The problem to which the invention is directed, is to obtain a damping alloy based on iron and products from it with a regulated level of damping and mechanical properties.

The technical result of the invention is to improve the mechanical properties (σ _0.2 and σ _in ) of the high damping alloy and products made from it, while maintaining a high level of damping properties.

The specified technical result is achieved in that the high damping alloy based on iron, containing carbon, aluminum, manganese, titanium, additionally contains copper and niobium in the following ratio of components, wt%:
Carbon - 0.010 - 0.035
Aluminum - 4.0 - 8.0
Manganese - 25 - 0.95
Titanium - 0.01 - 0.55
Niobium - 0.01 - 0.15
Copper - 0.01 - 0.20
Iron - Else
the total carbon and copper content is determined by the dependence Σ (5C + 1,5Cu) = 0.06 - 0.45%,
and the content of aluminum, manganese, titanium and copper is related by the ratio: while [Al - Σ (Mn + Ti + Cu)] = 3.5-6.5%.

The technical result is also achieved by the fact that the products are made of high damping alloy of the above composition, while they have the following level of damping and mechanical properties:
logarithmic decrement of fluctuations δ 15 -30%,
yield strength σ _0.2 340 - 430 MPa,
tensile strength σ _in 480 - 600 MPa,
elongation Δ 15 - 25%.

 The presence in the alloy of aluminum, manganese, titanium, niobium, copper and carbon within the specified limits provides high mechanical and damping properties of the alloy, and the content of these elements must correspond to the above dependencies. When the value of [Al - Σ (Mn + Ti + Cu)] is less than 3.5%, the damping properties of the alloy sharply decrease, and its increase to a value of more than 6.5% leads to an increase in the fragility of the material. The content of the proposed alloy 4.0 - 8.0% Al provides high values of the logarithmic decrement of vibrations due to the formation of a special structural state of the material. When the Al content is less than 4%, the damping properties of the alloy are sharply reduced. An increase in Al content of over 8% leads to an increase in the brittleness of the alloy and impairs its processability. An increased level of mechanical properties of the alloy compared to the prototype is achieved by additional alloying with copper, while the content of alloying elements must satisfy the relation Σ (5 C + 1.5 Cu) = 0.06-0.45%. With a decrease in Σ (5 C + 1.5 Cu) less than 0.06%, the mechanical properties of the alloy deteriorate sharply, and an increase in this value over 0.45% leads to an increase in the fragility of the material.

 The introduction of niobium (0.01 - 0.15%) into the alloy with a regulated content of (C + Cu) provides modification of the alloy structure and increases its manufacturability. When the Nb content is less than 0.01, no structural modification is observed and the manufacturability of the alloy remains unchanged. When the Nb content is more than 0.15%, the damping properties of the alloy deteriorate as a result of the formation of intermetallic phases.

 A manganese content in the amount of 0.25-0.95% is necessary to ensure high damping properties of the material and its manufacturability.

 A decrease in the manganese content below the specified limit leads to a decrease in the damping properties of the alloy as a result of the development of segregation heterogeneity. When the Mn content is more than 0.95% in the alloy with a regulated content (C + Cu), the damping ability is also reduced due to a decrease in the magnetic susceptibility of the alloy.

 Titanium is an effective hardener of solid solution and its content in the amount of 0.01 - 0.55% is necessary to maintain a high level of mechanical properties. The introduction of titanium also favorably affects the damping properties of the alloy. When the Ti content is less than 0.01%, the strength characteristics of the material decrease and its damping properties deteriorate due to an increase in coercive force. The introduction into the alloy with a regulated content (C + Cu) of more than 0.55% Ti leads to an unacceptable increase in the brittleness of the alloy.

 The introduction of more than 0.035% C or 0.2% Cu into the alloy leads to a deterioration in the damping properties due to a decrease in the mobility of the walls of the magnetic domains and an increase in hysteresis losses. When the content in the alloy is less than 0.01% C or 0.01% Cu, an unacceptable decrease in the strength properties of the material occurs.

 The implementation of the products of the proposed alloy provides a high level of their properties - both mechanical and damping.

Example 1. An alloy containing 5.6% aluminum, 0.01% carbon, 0.25% manganese, 0.02% titanium, 0.01% niobium, 0.02% copper, the remaining iron and impurities were smelted in open induction furnace with a capacity of 50 kg and was poured into ingots weighing 17 kg. The metal was redistributed into cold-rolled sheets with a thickness of 1.0 and 2.0 mm according to the scheme: forging on a flap - hot rolling into sheets with a thickness of 6.0 and 3.0 mm - heat treatment - etching - cold rolling to the required thickness. After machining (manufacturing samples for testing mechanical properties and damping ability), heat treatment was carried out in vacuum with holding at temperatures of 820-1020 ^o C and subsequent slow cooling. The damping ability of the material in the amplitude range Δ l / l = 10 ^-5 - 10 ^-3 ) was determined using the TsNIIchermet installation, assembled according to the reverse bending pendulum scheme, on standard samples of complex cross section and sheets 2.0 mm thick. After the above processing, the proposed alloy and products made from it have the following properties: logarithmic decrement of vibration δ 15 - 30%, conditional yield strength σ _0.2 to 380 MPa, tensile strength σ _in up to 530 MPa, elongation Δ up to 30%.

Example 2. An alloy containing 5.4% aluminum, 0.025% carbon, 0.25% manganese, 0.16% titanium, 0.01% niobium, 0.18% copper, the remaining iron and impurities were smelted in an open induction furnace capacity of 50 kg and was poured into ingots weighing 17 kg. The metal was redistributed into cold-rolled sheets with a thickness of 1.0 and 2.0 mm according to the scheme: forging on a flap - hot rolling into sheets with a thickness of 6.0 and 2.5 mm - heat treatment - etching - cold rolling to the required thickness. After machining (manufacturing samples for testing the mechanical properties and damping ability), heat treatment was carried out in vacuum with holding at temperatures of 820-1050 ^o C and subsequent slow cooling. The damping ability of the material was determined by the method described above. After metallurgical processing and heat treatment, the alloy and articles made therefrom have the following properties levels: logarithmic decrement δ of up to 16% proof stress σ _0.2 to 430 MPa, the tensile strength σ _is up to 600 MPa and elongation Δ up to 20%.

Claims (2)

1. High damping alloy based on iron with a regulated level of damping and mechanical properties, containing carbon, aluminum, manganese, titanium, characterized in that it additionally contains copper and niobium in the following ratio of components, wt.%:
Carbon - 0.010 - 0.035
Aluminum - 4.0 - 8.0
Manganese - 0.25 - 0.95
Titanium - 0.01 - 0.55
Niobium - 0.01 - 0.15
Copper - 0.01 - 0.20
Iron - Else
the total carbon and copper content is determined by the dependence Σ (5C + 1,5Cu) = 0.06 - 0.45%; and the content of aluminum, manganese, titanium and copper is related by the ratio [Al - Σ (Mn + Ti + Cu)] = 3.5 - 6.5%. 2. The product is made of an alloy of high damping based on iron with a regulated level of damping and mechanical properties, characterized in that it is made of an alloy according to claim 1 and has the following properties: logarithmic decrement of oscillations δ 15 - 30%; yield strength σ _0.2 340 - 430 MPa; tensile strength σ _in 480 - 600 MPa; elongation Δ 15 - 25%.