FR2509327A1 - Master alloy contg. numerous alloying elements including copper - for mfg. high strength alloy cast iron with pearlitic structure in both thick and thin cast sections - Google Patents

Abstract

The master alloy contains by wt. 3-7% nickel, 3-7.5% silicon, 1-3% chromium, 0.2-0.5% cobalt, 1-2.5% carbon, 1-7% copper, the remainder being iron. The alloy cast iron made using the master alloy is employed e.g. in mechanical structures, esp. in machine tools, where guides 40-150 mm thick are combined with thin cast sections of 15-30 mm. The master alloy produces cast irons with a pearlitic structure contg. no ferrite, and with increased resistance to wear.

Description

 The present invention relates to the foundry and particularly relates to a pre-alloy for the development of cast iron parts.

 The invention can be used most advantageously to improve the physico-mechanical and operating characteristics of castings used in mechanical constructions, more specifically in the construction of machine tools, and distinguished from other molded parts by constructive features. including a combination of solid guides (40 to 150) .10 m and walls and shafts (15 to 30) .103m thick.

 The properties of the cast iron are determined by its structure, whatever the factors that influenced it. The main process that forms the structure of the font is that of graphitization, which determines not only the quantity, shape and distribution of graphite, but also the nature of the metal base (matrix) of the font.

 The formation of the cast structure can be influenced by varying the chemical composition, cooling rate and other factors. This makes it possible to obtain one structure or another and, consequently, the desired mechanical properties of the cast iron (mechanical strength, hardness and others), as well as the properties of use such as wear resistance.

 The influence of the structure on the properties of cast iron is determined both by graphite and by the metal matrix (cementite, perlite, ferrite).

 It is known that graphite inclusions weaken the metal matrix and serve as voltage concentrators when applying a load. This primarily influences the tensile strength.

As for the hardness of the iron, it depends very little on the presence of graphite inclusions and is generally determined by the metal matrix
Ferritic iron Ferrito- Perlitic
pearlite
Hardness 1.50 2.00 2.50
GPa
The resistance of the cast iron to wear is influenced by both the graphite structure and that of the matrix. With regard to the gray cast iron, it should be noted that its resistance to wear is influenced by the length of the graphite inclusions and by the distance between them. The influence of the metal matrix is determined by the presence in it of inclusions of ferrite (soft areas) or phosphides, oerbures and other hard structural constituents of the pearlitic matrix.

 It is well known that the cooling rate and conditions of crystallization are different in the different parts of the molded part, which means that the structure and the properties of the molten metal are also different. These differences are especially noticeable in cast iron, whose structure and properties are strongly influenced by the rate of cooling as a result of degraphitization processes.

This is why cast iron has relatively low uniformity of properties (quasi-isotropy) and high sensitivity to cooling rate.

 To obtain a high quality molded part is not only to manufacture it from a cast iron having good physico-mechanical properties, but also to obtain all these properties in all the sections of the part. The known methods of adjusting the cooling rate (installation of coolers, artificial cooling with air and water circulation), although they equalize the temperature in the different parts of the molded part, make less homogeneous the thermal field in the section of the room on which the cooler acts directly. As a result, the structure of the cast iron piece at its ends and in the center of said section is substantially different.

 Under these conditions, such a method of action on the structure of the cast iron can not be regarded as advantageous, using chillers during the molding of machine tool parts, because despite the increase up to 1.80 - 2.00 GPa of the general hardness of the cast iron constituting the guides of these machines, there is no improvement in the resistance to wear (see, for example, "Chugunnoié litio v stankostroienii", edited by GI Kletskine, M., ed. "Mashinostroyenie, 19752 pp. 23-24).

 The sensitivity to the cooling rate of the cast iron strongly depends on its chemical composition. It is known that carbon is the element which has the greatest effect: the structure of the iron in its different sections is all the more homogeneous as its carbon content is lower. However, a decrease in the amount of carbon in gray cast iron to a value leading to the formation of white areas (appearance of free-form cementite) makes the structure extremely heterogeneous not only in the different sections of the cast iron, but also in each of the sections.

 Different processes for producing cast irons having the desired homogeneous structure, in particular a pearlitic structure, are known.

 One of these known methods is the off-oven inoculation of the liquid metal by means of inoculating agents.

In this case, there appears in the molten metal a temporary submicroscopic heterogeneity causing the formation of an increased amount (relative to the equilibrium or equilibrium quantity) of graphitization centers, so that the melt solidifies without any appearance of white areas. However, it is known that the action of inoculants is a function of time and is most pronounced 1 to 5 minutes after their introduction, the inoculation effect subsequently decreasing with the increase of the maintenance time of the melt and disappearing completely after 15 to 30 minutes.

 For this reason, the method described could not find any application in the molding of solid parts.

 The most common method of producing heavy parts is the alloy either in the pocket (excluding the oven) or directly in the melting furnace.

 In the production of molded parts for mechanical constructions, especially for machine tools, nickel, chromium, and the like are used as addition elements.

copper, molybdenum, titanium. These elements are introduced into the cast iron either in the form of pure metals (nickel, copper), or in the form of ferroalloys (ferro-chromium, ferro-molybdenum), or else in the form of cast iron containing natural additions (nickel-chromium, titanium-copper cast iron).

 The use of these elements is due to their action on the variation of the tendency of the melt to the graphitization.

 It is known that nickel and liquid copper accelerate the graphitization process of cast iron during the eutectic and austenitic transformation.

In the case of a eutectoid transformation, they slow down the graphitization by preventing the formation of ferrite and promoting the formation of a pearlitic structure.

The use of nickel and copper is also advantageous because they prevent the appearance of white areas in the molded parts
As for chromium and molybdenum, they slow down the graphitization processes at all stages by acting with an intensity that increases with their concentration.

A beneficial action on gray iron is exerted by these elements which cause a notable refinement of the graphite and, consequently, an improvement of the characteristics of the melt.

Titanium is an element that is contained in titanium-copper pig iron in a proportion of up to 1.2% and which acts on the structure in two different ways depending on its proportion in the cast iron. When the content of the iron-titanium does not exceed 0.08 to 0.01%, the latter acts as a graphitizing element, whereas when said proportion reaches 0.1 to 0.2%, it exerts an anti-graphitizing action, of so that carbides and nitrides of titanium are formed whose presence in the metal matrix of the cast iron constituting the machine tool guide moldings reduces their resistance to wear, these extradure inclusions acting as abrasives. of weak mold dimensions, titanium contents of 0.1 to 0.2% cause the formation of white areas and consequently of a non-homogeneous structure in the different parts of the molded parts.
In practice, the combined alloy process is generally employed. Thus, the cast iron can be combined with chromium and nickel by simultaneously using the two elements in sufficient quantities for the whitening effect produced by the chromium to be compensated for by the graphitizing effect of the nickel (during the eutectic transformation). allows to obtain a pearlitic structure in the massive parts of the molded parts.

 However, the use of metals which are particularly high chromium and nickel-containing ferroalloys as pocket addition elements does not ensure a uniform distribution of the alloying elements throughout the metal volume nor their assimilation. complete. The distribution of alloy elements in the metal volume during a single process (cupola melting) becomes even more irregular if pure metals and high-element ferroalloys are introduced into the vessel. additionally with the charge. In addition, a high loss of alloying elements is observed.

 The alloying process in the furnace, that is to say the introduction of alloy elements in the form of cast iron already containing natural additions, directly into the load, is the most efficient method for improving the characteristics cast iron constituting the castings.

 However, in the last 30 or 40 years, the ratios of the main alloying elements (chromium and nickel) in cast iron have changed as a result of the change in the composition of the ores in an unfavorable way, by 1: 2 -3 to 2-3: 1, that is to say, the amount of chromium now exceeds the amount of nickel by 2 to 3 times. In order to neutralize the anti-graphitizing effect of chromium and, consequently, to avoid the appearance of white areas in the small sections of the molded part, an additional quantity of nickel is introduced into the cast iron. not recommended especially because of the irregular distribution of nickel in the volume of the cast iron during its elaboration at low temperature.

 In addition, if nickel-chromium cast iron is used, no more than 10% of the pig iron may be introduced into the feed. Indeed, the use of smelting melt requires an increase in the amount of steel-to lower the content of the cast iron made of carbon. At the same time, it is necessary to introduce into the feed ferro-silicon containing 20 to 25% Si.

Such a process does not ensure a regular concentration of silicon in the molten metal. The variations in the silicon content from one pocket to another are then +0.4%, which causes the appearance of white areas in the thin or ferrite sections in the solid parts of the molded parts.

 The use of a titanium-copper cast iron is limited by the need to introduce into the metal to be developed, titanium whose influence on the formation of the structure of the molded parts is described above. If a refining cast iron is used in the feed, the additional addition of copper to the ladle does not provide a regular distribution of the other elements (eg silicon) in the elaborate cast iron and does not allow for avoid the appearance of white areas in thin sections of castings. The irregularity of the structure in the different sections causes the appearance of high internal stresses resulting in warping of the parts and sometimes even the appearance of cracks.

An alloy is known (see the certificate dtautegr
USSR N 449977, Cl. Int.C22C35 / 00, published 15.11.74) containing the following components,% by weight:
nickel 6-20
chrome 1-2
0.8-1.0 silicon
0.2-0.5 cobalt
carbon 1,2
iron the rest.

 The ratio of nickel to chromium in this alloy varies from 3: 1 to 20: 1 (most often 10: 1), which is extremely advantageous from the point of view of the assimilation of nickel by melting and its action. on the graphitization of the latter. However, to ensure the refinement of graphite, it is necessary to introduce chromium into the cast iron, which does not favor the stabilization of the chemical composition of the cast iron and, consequently, the homogeneity of the structure. The introduction of silicon also contributes to the no. homogeneity of the composition.

On the other hand, given the low content of the silicon alloy, the application possibilities of the pig iron are limited.

Another known pre-alloy having for composition, mass
nickel 3,5-7,0
3.0-7.5 silicon
chrome 1,0-D, 0
0.1-0.5 cobalt
1.5-2.5 carbon
iron the rest (see the review "Tsvetnyé métally" - nMetals non-ferreux "-1978, N011) eliminates the disadvantages indicated previous alloying processes and ensures obtaining a pearlitic matrix in the guides, a thickness up to 80.10 m, molded parts whose mass reaches 20 to 25 tons.

When we produce guide parts. From 80 to 10 m, with only 10 to 15 t, ferrite appears in the structure of the iron despite the nickel and chromium alloy. The presence of this ferrite reduces the wear resistance.

 It is because of these peculiarities that it is disadvised to use the pre-alloy of composition indicated for the production of cast iron parts in which walls and thin edges (15 to 40) .03m are associated with massive guides ( more than 80.10- m).

 It has therefore been proposed, by suitably selecting components promoting goephitization and preventing the formation of ferrite, to create an optimal composition of pre-alloying, which would increase the resistance of the cast iron to wear in the molded parts, gracie to obtain a homogeneous structure (pearlitic).

This object is achieved because the pre-alloy for the production of cast iron parts, of the type containing nickel, silicon, chromium, cobalt, carbon and iron, is characterized according to the invention in that it also comprises copper, the proportions of the substituents being as follows (% by weight)
nickel 3-7
3-7,5 silicon
chrome 1-3
0.2-0.5 cobalt
1-2.5 carbon
copper 1-7
iron the rest.

 The copper introduced into the pre-alloy, favoring graphitization, at the same time makes the disintegration of pearlite difficult and considerably lessens the difference in the proportions of combined carbon contained in the thin and thick sections. As a result, the white areas in the thin sections and the crystallization of the ferrite in the thick sections are eliminated, so that a homogeneous pearlitic structure is formed in all the sections. In addition, the copper additionally consolidates the ferrite and promotes the hardening. by precipitation and refinement of pearlite, which increases the wear resistance of the cast iron constituting the castings.

 The introduction of copper in the pre-alloy in an amount of less than 1% n1 improves neither the microstructure nor the properties of the cast iron.

 On the other hand, the introduction into the pre-alloy of more than 7% of copper is to be discouraged, since in this case the technical effect obtained does not justify the additional expense of copper.

The invention will be better understood and other objects, details and advantages thereof will appear better in the light of the explanatory description which follows of an embodiment given solely by way of non-limiting example.
In a 50 kg capacity crucible induction furnace, a pre-alloy having the composition
nickel 4.35
silicon 5,18
chrome 2.28
cobalt 0.49
2.38 carbon in the form of easy-to-crack ingots having a mass of up to 40 kg in an amount of 30 to 44.5 kg. The furnace is turned on, the pre-alloy is melted and the temperature is raised to 1380 ° C. at this temperature, 0.25 to 1.6 kg of granulated nickel 0.05 to 2.7 kg are introduced into the molten pre-alloy. ferro-silicon pieces (Si = 75, '); 0.8 to 1.4 kg pieces of ferro-chromium (Cr = 65%) 0.5 to 3.6 kg of cathodic copper pieces measuring (5 to 6x20x40) .10 -m; and 0.5 to 14.8 kg of steel in the form of corner iron waste. After maintaining at a temperature of 1380 ° C. for 5 to 7 minutes, the cuprous pre-alloy is cast in molds. The solidified and cooled cuprous pre-alloy in the form of ingots is used as a filler for producing alloy cast iron.

 The development of the alloy cast is as follows.

 On the bottom of the crucible of a high-frequency induction furnace 0.15 to 0.25 kg of cementum (electrodes waste) of a size ranging from (i to 3) to 10 m; 17.5 to 20 kg of ingots ripening iron; 12.5 to 12.95 kg of scrap steel in the form of waste; 10.75 to 15 kg of cast iron scrap in the form of waste; and 2.5 to 7.5 kg of pre-alloy. The furnace is started, the components of the charge are melted, the molten metal is heated up to 145 ° C. and the slag is dechlorinated. Then 0.1 to 0.3 kg of molten metal is introduced onto the mirror. ferro-manganese, containing 75% Mn, in the form of 5 to 20 mm pieces. The ferro-manganese being dissolved, 0.15 to 75 kg of ferro-silicon containing 75% of Si are introduced in the form of pieces. After maintaining the metal in the oven at a temperature of 1450 ° C for 7 to 10 minutes, the metal is cooled with the furnace to 1400 ° C., poured into a pocket and molds of test specimens 30.10- m and a length of 340.10- m, to study the structure and mechanical characteristics, as well as specimens of (120x200x300) .10- m pwr einIer the structure and hardness.The temperature of the molding operation specimens is 1340 to 13500C in all cases.

 The laboratory study of the properties of the cast iron is carried out according to the technique described below.

 To determine the tensile strength of the cast iron, samples obtained by turning were used from the test pieces of 30 × 10 3 m in diameter. The diameter of the samples is (15 + 0.1) .10 3m, and the length of the working part, 90.10 3m. For this purpose, a traction machine of 196 kN (20tf) maximum is used. Microstructure is studied on isolated coupons. The hardness is measured on a Brinell press under a load of 29.4 kN (3000 kg), the diameter of the ball being equal to 10.10-m, at a distance equal to half the radius of the test piece.

 For the analysis of the microstructure and the hardness of the melt in the (120x200x300) 10 m specimens, coupons obtained from the lower part of the test piece are used at a height of 15.10 μm using the same way as before. The microstructure is studied under a microscope. The structure of the graphite is studied with a magnification equal to 50, the metal matrix with a magnification equal to 400, and the dispersity of the perlite, with a magnification of 1000.

 The concrete but nonlimiting examples below, illustrating the present invention, highlight its particularities and advantages.

 Example 1

In order to prepare alloyed cast iron, a cuprous pre-alloy is prepared with the following composition,% by weight
nickel -3.21
cobalt -0.36
chrome -1.69
silicon -7.23
carbon -1.78
copper -0.98
iron -84.75
The pre-alloy is manufactured in an induction furnace with a crucible of 50 kg capacity. As filler materials, a chromium-nickel pre-alloy is used in the form of ingots of the following composition, in en masse.
nickel -4.35
cobalt -0.49
chrome -2.28
silicon -5.18
carbon -2.38
iron -85,32 debris of steel, ferro-silicon (Si = 75%) and cathodic copper.Prealloy is obtained in the following way
In the crucible of an induction furnace, 37 kg of chromium-nickel pre-alloy are charged, the furnace is started, the pre-alloy is melted, the temperature of the melt is raised to 138 ° C., it is introduced 9 9 kg of steel debris, the temperature was lowered back to 1380 C and 2.6 kg of small pieces of ferro-silicon (Si = 75, ') were introduced. When the ferrosilicon is dissolved, 0.5 kg of small pieces of copper are added. Melt pre-alloy was maintained at 1380 ± 10 ° C for 5 to 7 minutes and poured into the molds.

The load used for the elaboration of the alloy cast has for composition, in mass
cuprous pre-alloy - 5.0
ripening iron -37.0
steel scrap -25,9
cast debris -30.0
ferro-silicon (Si = 75%) - 1.1
ferro-manganese (Mn + 75%) -I 0.6
cementum (electrode waste)
The technique of elaboration of the-melt consists of the following. 0.2 kg of cement, 12.95 kg of scrap steel in the form of waste, 18.5 kg of refining cast iron in the form of slotted ingots and 15 kg of cast iron scrap are loaded onto the bottom of the crucible. form of waste (samples already used for mechanical tests). The furnace is started, the charge is melted, the temperature of the molten metal is raised to 1450 ° C. ± 20 ° C., the slag is removed, and 0.3 kg of ferro-manganese (at 75 ° C.) is introduced into the mirror. % of Nn) and, when the ferro-manganese is dissolved, 0.55 kg of ferro-silicon (Si = 75%) is added. The ferro-silicon being dissolved, the metal is maintained in the oven at a temperature of 1450 ° C. for 7 to 10 minutes, the molten metal is cooled to 1400 ° C. with the furnace and poured into a ladle. The casting of test pieces is carried out at a temperature of 1340 to 13500 C. The temperature of the liquid metal is controlled using a Pt-Rh-Pt immersion thermocouple.

 When the specimens are solidified, cooled and discarded from the molds, the following tests are carried out. The chemical composition of the cast iron is determined in% by mass. 30.10 mm diameter specimens were prepared by turning samples with a diameter of 15.10 μm and the length of the working part at 90 μm for the tensile tests. coupons of (30x20) .10 -m for hardness and micrographic tests. From samples of (120x200x300) .103 m, samples of (80x60x85) are cut .10- m hens hardness tests and (40x30x20) .10- m, for the analysis of the structure. The surface of the sample on which the hardness and micrographic tests are carried out is placed at 15 × 10 -m from its lower surface.

 The test results are as follows.

 The chemical structure of the cast iron obtained is as follows,% by weight: carbon - 3.16; silicon - 1.82 manganese -0.85; phosphorus -0.12; sulfur -0.11 nickel -0.20; copper -0.05; chromium -0.14 (Table 1).

The tensile strength is 273 + 12 MPa. The hardness of the samples 30.10 3m in diameter is equal to 2.27
GPa, and that of the samples of (120x200) .10-m section, to 1.39 GPa.

 The microstructure of the cast iron in the 30.10-m diameter test pieces is as follows: 96% perlite (P 96); amount of ferrite -4% (Fe 4); dispersity of perlite -1.0 (Pd 1.0); length of inclusions of graphite (lgr - 173.10-6m).

 The microstructure of the cast iron in the test specimens with (120x200) .10 m section is as follows: amount of perlite -85% (P 85); dispersity of perlite -1.6 (Pd 1.6); amount of ferrite -15% (Fe 15); length of inclusions of graphite (lgr -440.10-6m) (Table 2).

 ExempLe 2.

 The cuprous pre-alloy for the production of the cast iron has a composition analogous to that of Example 1.

The charge for the evaporation of the cast iron has for composition,% by mass
cuprous pre-alloy 10.0
ripening iron 38.0
25.2 steel scrap
cast iron debris 25.0
ferro-silicon (Si = 75%) 0.8
ferro-manganese (Mn = 75%) 0.6
0.4 cement
The manufacture of the cuprous pre-alloy and the melt is carried out in the same manner as in Example 1.

 The test results are as follows.

 Chemical composition of the elaborated fiber,% by weight: carbon-3.05; silicon-1.95; manganese-0.73; P-0.15; sulfur-0.10; nickel-0.35; copper 0.11; chromium-0.20 (Table 1). The tensile strength is 305 # 15 a; hardness of samples with a diameter of 30 × 10 3 m -2.23 GPa; hardness of samples with (120x200) .10- m section, 1.52 GPa. Microstruture in samples with a diameter of 30.10 3m: metal matrix - perlite (P), dispersity (Pd) 1.0; 1,165.10 6 ni, and in the samples with a section of (120x200) 10-m metal matrix -P 85, Fe 15, P, d 1.6.1gr = 418.10-6m (Table 2).

 Example 3

The cuprous pre-alloy for the preparation of the cast iron has a composition analogous to that of Example 1. The charge for the production of cast iron has for composition, in mass
cuprous pre-alloy -15.0
ripening iron -33,6
scrap steel -25.0
cast debris -25.0
ferro-silicon (Si = 75%) - 0.3
ferro-manganese (Mn = 75%) - 0.6
cementitious - 0.5.

 The preparation of the cuprous pre-alloy and the preparation of the melt are carried out as in Example 1.

 The test results are as follows.

 Chemical composition of the cast iron: carbon -3.03; silicon -2.05; manganese -0.81; phosphorus -0.16; sulfur -O, 12; nickel -0.48; copper -0.16; chromium -0.28 (Table 1).

 The tensile strength was 328 ± 21 hardness samples of 30 × 10 -3 m diameter -2.35 GPa, hardness of samples with (120 × 200) .10-m section, 1.59 GPa.

Nicrostructure of samples with a diameter of 30.10-m: metal matrix -P, Pd 0.5, + = 148.10-6m; microstructure samples with (120x200) .10- m section; metal matrix -P 92; Pd 1.4, Fe-8, lgr = 395, (Table 2)
Example 4

In order to prepare the alloy cast iron, a cuprous pre-alloy is prepared with the composition,% by weight
nickel -6.8
cobalt -0.41
chrome -1.89
silicon -7.02
copper -1.18
carbon -1.98
iron -80.72
For the manufacture of the cuprous pre-alloy, use is made of a filler of the following composition,% by weight
chrome-nickel pre-alloy -74
scrap steel -19,8
Ferro-silicon (Si = 75%) - 5.2
cathode copper - 1.0
The pre-alloying is done in the same manner as in Example 1.

For the development of the cast iron, a feed containing,% by weight is used
cuprous pre-alloy - 5.0
ripening iron - 40.0
scrap steel - 25.0
cast iron debris - 28.2
ferro-silicon (Si = 75%) - 1.0
ferro-manganese (Mn = 75%) - 0.5
cementitious - 0.3.

 The development of the cast iron is carried out as described in Example 1.

 The test results are as follows.

 Chemical composition of the cast iron,% by weight: carbon - 3.18; silicon - 1.94; manganese - 0.75 phosphorus - 0.14; sulfur - 0.09; nickel - 0.34; copper - 0.07; chromium - 0.13 (Table 1).

 Tensile strength - 279 + 13 NPa.

Hardness of samples with a diameter of 30.10- m-2.41
GPa; hardness of samples with (120x200) section .10 3m - 1.41 GPa.

 Microstructure of cast iron in samples with a diameter of 30.10-m: metal matrix - P, Pd 0.5 l r = 148.106ni; with a section of (120x200) .10 3m :: P 85 metal matrix, Pd 1.6, Fe 15, lgr = 415.10-6m (Table 2).

Example 5
The composition of the cuprous pre-wire for the smelting is similar to that described in Example 4.

The filler used to develop the melt alloyed with the following composition,% by weight
cuprous pre-alloy - 10.0
ripening iron - 37.0
scrap steel - 30.0
cast iron debris - 21.5
ferro-silicon (Si = 75%) - 0.7
ferro-manganese (Mn = 75%) - 0.4
cement - - 0.4.

 The cuprous pre-alloy and the melt are obtained as in Example 1.

 The test results are as follows.

 Chemical composition of cast iron,% by weight of carbon - 2.95; silicon - 1.98; manganese - 0.82 phosphorus - 0.13; sulfur - 0.10; nickel - 0.67; copper - 0.14; chromium - 0.22 (Table 1).

 Tensile strength - 311+ 12 MPa.

 Hardness of the samples: with a diameter of 30 × 10 -m - 2.38 GPa, with a section of (120 × 200) × 10 -m - 1.59 GPa.

Microstructure of samples with a diameter of 30.10-m; metal matrix -P, 0.5 Pd; graphite 1gr = 151.103m with a section of (120x200) .10 3m: P 85 metal matrix,
Pd 1.4, Fe 15, 1gr graphite = 403.10 mm (Table 2).

Example 6
The composition of the cuprous pre-alloy for the manufacture of the cast iron is similar to that of Example 4. The load for the manufacture of the cast iron has for composition, in mass
cuprous pre-alloy - 15.0
ripening iron - 35.0
scrap steel - 25.0
cast iron debris - 23.8
ferro-silicon (Si = 75%) - 0.3
ferro-manganese (Mn = 75%) - 0.4)
cementitious - 0.5.

 The preparation of the cuprous pre-alloy and the melt is carried out as described in Example 1.

 The test results are as follows.

 Chemical composition of cast iron,% by weight: carbon - 2.91; silicon - 2.10; manganese - 0.76; phosphorus - 0.13; sulfur - 0.10; nickel --0.99; copper - 0.22; chromium - 0.32 (Table 1).

 Tensile strength - 326 + 18 MPa.

 Hardness of the samples: with diameter of 30.10 3m - 2.35 GPa, with section of (120x200) .10- m - 1.65 GPa.

 The microstructure of the samples with a diameter of 30.10 -m: metal matrix - P, Pd 0.5; lgr = 110.10-6m; section of (120x200) .10 -m: metal matrix - P 92, Pd 1.4, Fe 8, lgr = 385.106m (Table 2).

Example 7
In order to form alloyed cast iron, a cuprous pre-alloy is prepared with the composition,% by weight
nickel - 6.99
cobalt - 0.44
chrome - 2,83
silicon - 4.60
copper - 4.38
carbon - 2.41
iron - 78.35
The charge used to prepare the cuprous pre-alloy is composition% by weight
chrome-nickel pre-alloy - 89.0
scrap steel - 1.0
granulated nickel - 3.2
Ferro-chromium (Cr = 65, ') - 1.6
cathode copper - 4.4
cement - 0.8.

 The pre-alloying procedure is analogous to that of Example 1.

The charge for the preparation of the cast iron has for composition,% by mass
cuprous pre-alloy - 5.0
ripening iron - 40.0
scrap steel - 25.0
cast iron debris - 28.0
ferro-silicon (Si = 75) - 1.3
ferro-manganese (Mn = 75, ') - 0.4
cament - 0.3.

 The procedure for making the cast iron and pouring the samples is similar to that of Example 1.

 The test results are as follows.

 The chemical composition of the cast iron is as follows, in carbon mass - 3.10; silicon - 1.78; manganese - 0.71 phosphorus - 0.13; sulfur - 0.08-; nickel - 0.34; chromium - 0.16; copper - 0.21 (Table 1).

 Tensile strength - 281 + 16 MPa.

 Hardness of the samples: with a diameter of 30.10- m - 2.38 GPa, with a section of (120x200) .10 3m - 1.41 GPa.

 The microstructure of the iron in the samples with a diameter of 30 × 10 3 m: metal matrix -P, Pd 1.0 lgr = 145 × 10 -m; with section of (120x200) .10- m; metal matrix - P 85, Pd 1.6, -Fe 15, lgr = 435.10-@m (Table 2).

Example 8
The composition of the pre-alloy for the manufacture of the cast iron is similar to that of Example 7. The load used for the development of the cast iron composition is,% by weight
cuprous pre-alloy - 10.0
ripening iron - 38.0
scrap steel - 25.0
cast iron debris - 25.2
ferro-silicon (Si = 75%) - 0.8
ferro-manganese (Mn = 75%) - 0.5
cementitious - 0.5.

 The procedure for manufacturing the cuprous pre-alloy and cast iron is similar to that described in Example 1.

 The test results are as follows.

 Chemical composition of cast iron,% by mass of carbon - 3.01; silicon - 1.84; manganese - 0.72 phosphorus - 0.14; sulfur - 0.08; nickel - 0.68 chromium - 0.34; copper - 0.42 (Table 1).

 Tensile strength - 331+ 11 MPa.

Hardness of the samples: with diameter of 30.10- m - 2.29
GPa, with a section of (120x200) .10- m - 1.69 GPa.

 Microstructure of the iron in samples with a diameter of 30.10 -m: metal matrix P, Pd 0.5 lgr = 125.10-6m; with a section of (120x220). 10-m: metal matrix P 96, Pd 1.0, Fe 4, lgr = 385.10-6m (Table 2).

Exemption 9
The composition of the cuprous pre-alloy for the production of the cast iron is similar to that of Example 7. The charge for the production of the cast iron has the following composition, by weight
cuprous pre-alloy - 15.0
ripening iron - 35.0
scrap steel - 25.0
cast iron debris - 23.4
ferro-silicon (Si = 75%) - 0.6
ferro-manganese (Mn = 75%) - 0.5
cement - 0.5
The procedure for producing the cuprous pre-alloy and the melt is similar to that of Example 1.

 The test results are as follows.

 Chemical composition of cast iron,% by weight of carbon - 2.94; silicon - 1.95; manganese - 0.89 phosphorus - 0.12; sulfur - 0.10; nickel - 1.05 chromium - 0.48; copper 0.65 (Table 1).

 Tensile strength - 353+ 15 MPa.

 Hardness of the samples: with diameter of 30.10- m - 2.38 GPa; with section of (120x200) .10- m - 1.83 GPa.

 Microstructure of the iron in the samples with a diameter of 30.10 -m: metal matrix P, Pd 0.3 lgr = 95.10-6m; with a section of (120x200) .10-: metal matrix P 96, Pd 1.0, Fe 4, lgr = 365.10-6m (Table 2).

Example 10
In order to form alloyed cast iron, a cuprous pre-alloy is prepared with the composition,% by weight
nickel - 3.11
cobalt - 0.29
chrome - 2.91
silicon - 3.16
copper - 6.97
carbon - 1.43
iron - 82.13.

To prepare the cuprous pre-alloy, a filler having the composition,% by weight
chrome-nickel pre-alloy - 60
scrap steel - 29.6
granulated nickel - 0.5
Ferro-chromium (Cr = 65%) - 2.8
ferro-silicon (Si = 75%) - 0.1
cathode vouivre - 7.0.

The procedure for manufacturing the pre-alloy is similar to that of Example 1. The load used for the production of the cast iron has the following composition,% by weight
cuprous pre-alloy - 5.0
ripening iron - 40.0
scrap steel - 25.0
cast iron debris - 27.8
ferro-silicon (Si = 75%) - 1.5
ferro-manganese (Mn = 75%) - 0.4
cementitious - 0.3.

 The procedure for making the cast iron and pouring the samples is similar to that of Example 1.

 The test results are as follows.

 The chemical composition of the pig iron is as follows,% by weight: carbon - 2.96; silicon - 1.98; manganese - 0.86; phosphorus - 0.14; sulfur - 0.11; nickel - 0.18 copper - 0.33; chrome - 0.15 (table 1).

 Tensile strength -293 + 13 MPa.

 Hardness of the samples with diameter of 30.10- m - 2.35 GPa, section of (120x200) .10 3m - 1.49 GPa.

 Microstructure-of the cast iron in the samples with a diameter of 30.10-m: metal matrix P, Pd 1.0 lgr = 128.10-6m; with a section of (120x200) 10-m: metal matrix P 92, Pd 1.4 Fe 8, lgr = 405.106m.

Example
The composition of the cuprous pre-alloy for making cast iron is similar to that of Example 10. The charge for the preparation of cast iron for composition,% by weight
cuprous pre-alloy - 10.0
ripening iron - 38.0
scrap steel - - 25.0
cast debris - 25.0
ferro-silicon (Si = 75%) - 1.2
ferro-manganese (Mn = 75%) - 0.4
cementitious - 0,4
The procedure for producing the cuprous pre-alloy and the melt is similar to that of Example 1.

 The test results are as follows.

 The chemical composition of the cast iron is as follows,% by weight: carbon - 2.98; silicon - 1.91 manganese - 0.74; phosphorus - Q, 14; sulfur - 0.10 nickel - 0.32, copper - 0.70; chromium - 0.31 (Table 1).

 Tensile strength - 334 + 13MPa.

 Hardness of the samples: with diameter of 30.10- - 2.38 GPa, with section of (120x200) .10- - 1.72 GPa.

 Microstructure of cast iron in samples with a diameter of 30.10-m: metal matrix - P, Pd 0.5; lgr = 120.10-6m; with a section of (120 × 200) 10-m: metal matrix P 96, Pd 1.0, Fe 4, lgr = 380 × 10 -6 μm (Table 2).

Example 12
The cuprous pre-alloy has a composition analogous to that of Example 10. The charge for the production of the alloy cast iron has the composition,% by weight
cuprous pre-alloy - 15.0
ripening iron - 35.0
scrap steel - 25.0
cast iron debris - 23.0
-ferro-silicon (Si = 75%) - 1.0
ferro-manganese (Mn = 75) - 0.5
cementitious - 0.5.

 The procedure for manufacturing the cuprous pre-alloy and cast iron is similar to that of Example 1.

 The test results are as follows.

 The chemical composition of the cast iron is as follows, in mass: carbon - 3.02; silicon - 1.73; manganese - 0.88, phosphorus - 0.12; sulfur - 0.08; nickel - 0.48; copper - 1.05; chromium - 0.45 (Table 1).

 Tensile strength - 351 + 14 MPa.

 Hardness of the samples: with a diameter of 30.10- m - 2.38 GPa, with a section of (120x200) .10 3m - 1.85 GPa.

 Microstructure of the cast iron in the samples with a diameter of 30.10 3m: metal matrix P, Pd 0.3 lgr = 95.10-6m; at (120 × 200) 10-μm section: metal matrix P 96, Pd 1.0, Fe 4 g = 3 × 10 -6 μm (Table 2).

Example 13
To produce alloyed cast iron, a cuprous pre-alloy is produced with the composition,% by weight
nickel - 3,22
cobalt - 0.36
chrome - 3.05
silicon - 7.48
copper - 7.18
carbon - 2.50
iron - 76.21.

For the preparation of the cuprous pre-alloy, a filler having the composition,% by weight is used
chrome-nickel pre-alloy - 74.0
scrap steel - 10.0
Ferro-chromium (Cr = 65%) - 2.4
ferro-silicon (Si = 75%) .- 5.4
cathode copper - 7.2
cementation -1.0.

 The preparation procedure for the cuprous pre-alloy is similar to that of Example 1.

The filler for elaboration of the alloy cast has the following composition, in% by weight
cuprous pre-alloy - 5.0
ripening iron - 40.0
scrap steel - 25.0
cast iron debris - 27.9
ferro-silicon (Si = 75%) - 1.2
ferro-manganese (Mn = 75%) - 0.5
cementitious - 0.4.

 The procedure for making the cast iron and pouring the samples is similar to that of Example 1.

 The test results are as follows.

 The chemical composition of the cast iron is the following% by mass: carbon - 2.93; silicon - 1.88; manganese - 0.78; phosphorus - 0.13; sulfur - 0.09; nickel - 0.17 copper - 0.35; chromium - 0.18 (Table 1).

 Tensile strength - 293+ 12 MPa.

 Hardness of the samples: with a diameter of -30.10 3m - 2.38 GPa, with a section of (120x200) .10 3m - 1.52 GPa.

 Microstructure of cast iron in samples with a diameter of 30.10-m: metal matrix P, Pd 1.0, lgr = 143.10-6m: with a section of (120x200) 10-m: metal matrix P 92, Pd, 1.6 , Fe 8 lgr = 418.10-@m (Table 2).

Exemption 14
The cuprous pre-bonding for the manufacture of the cast iron has a composition analogous to that of Example 13.

The load used for the preparation of the cast iron has for composition, in mass
cuprous pre-alloy -1Q, O
ripening cast iron - 38,0-
scrap steel - 25.0
cast iron debris - 25.2
ferro-silicon (Si = 75%) - 1.0
ferro-manganese (Mn = 75%) - 0.4
cementitious - 0.4.

 The procedure for manufacturing the cuprous pre-alloy and cast iron is similar to that of Example 1.

 The test results are as follows.

 Chemical composition of cast iron,% by mass carbon - 2.93, silicon - t, 88, manganese - 0.78 phosphorus - 0.13; sulfur - 0.09; nickel - 0.32; copper - 0.71; chromium - 0.33 (Table 1).

 Tensile strength - 330 + 13 MPa.

 Hardness of the samples: with diameter of 30.10 3m - 2.35 GPa; with section of (120x200) .103m - 1.75 GPa.

 Microstructure of the iron in the samples with a diameter of 30.10 -m: metal matrix P, Pd 0.5, lgr = 103.10-6m; with a section of (120 × 200) 10-m: metal matrix P 96, Pd 1.0, Fe 4, lgr = 380 × 10 -6 μm (Table 2).

Example 15
The composition of the cuprous pre-alloy for the manufacture of the cast iron is similar to that of Example 13. The load used to develop the cast iron has the following composition,% by weight
cuprous pre-alloy - 15.0
ripening iron - 35.0
scrap steel - 25.0
cast iron debris - 23.4
ferro-silicon (Si = 75%) - 0b6
ferro-manganese (Mn = 75%) - 0.5
cementitious - 0.5.

 The procedure for manufacturing the cuprous alloy and cast iron is similar to that of Example 1.

 The test results are as follows.

 Chemical composition of cast iron,% by mass of carbon - 2.97; silicon - 2.01; manganese - 0.85 phosphorus - 0.12 sulfur - 0.01; nickel - 0.52; copper - 1.09; chromium - 0.51 (Table 1).

 Tensile Strength - 349+ 16MPa.

 Hardness of the samples: with a diameter of 30.103m - 2.38 GPa, with a section of (120x200) .10- m - 1.85 GPa.

 Microstructure of the cast iron in the samples with a diameter of 30.10-m: metal matrix P, Pd 0.3, lgr = 93.10-6m; with section of (120x200). 10-m: metal matrix P 96, Pd 1.0, Fe 4, lgr = 365 × 10 -6 μm (Table 2).

Example 16 (for comparison)
To develop an alloy cast, a chromium-nickel pre-alloy of the following composition is used, mass%
nickel - 4.35
cobalt - 0.49
chrome - 2,28
silicon - 5.18
carbon - 2.38
iron - 85.32.

The charge for making the cast iron has the following composition,% by mass
ripening cast iron - 40
scrap steel - 26
cast iron debris - 26.7
chrome-nickel pre-alloy - 5.0
ferro-silicon (Si = 75%) - 1.4
ferro-manganese (Mn = 75, ') - 0.6
cementitious - 0.3.

 The procedure for making the cast iron is similar to that of Example 1.

 The test results are as follows.

 Chemical composition of cast iron,% by weight: carbon - 3.20; silicon - 1.75; manganese - 0.91; phosphorus - 0.12; sulfur - 0.08; nickel - C, 27; chromium - 0.16 (Table 1).

 Tensile strength - 268 + 16 MPa.

 Hardness of the samples: with diameter of 30.10- m - 2.38 GPa, with section of (120x200) .10- m - 1.41 GPa.

 Microstructure of the iron in the samples with a diameter of 30.10 -m: metal matrix P 96, Pd 1.4, Fe 4, lgr = 168.106m; with a section of (120x200) .10 m: metal matrix P 70, Pd 1.6, Fe 3; lgr = 450.10-@m.

Exemption 17 (for comparison)
The charge for making the cast iron has the following composition,% by weight.

ripening cast iron - 38
scrap steel - 25
cast iron debris - 25.2
chrome-nickel precharging - 10
ferro-silicon (Si = 75%) - 1.0
ferro-manganese (Mn = 75%) - 0.5
cementitious - 0.3.

 The procedure for making the cast iron and pouring the samples is similar to that of Example 1.

 The test results are as follows.

 Chemical composition of cast iron,% by weight carbon - 3.17; silicon - 1.83; manganese - 0.88 phosphorus - 0.12; sulfur - 0.1d; nickel - 0.49; chromium - 0.25 (Table 1).

 Tensile strength - 298 + 16 MPa.

 Hardness of the samples: with a diameter of 30.10- m - 2.35 GPa, with a section of (120x200) .10 3m - 1.52 GPa.

 Microstructure of the iron in the samples with a diameter of 30.10 3m: metal matrix P, Pd 1.0, lgr = 143.106m; with a section of (120 × 200) 10-m: metal matrix P 85, Pd 1.4 Fe 15, gr = 435 × 10 6 μm (Table 2).

Example 18 (for comparison)
The load used to make cast iron has the following composition, 96 by weight
ripening cast iron - 35
scrap steel - 25
cast iron debris - 23.3
chrome-nickel pre-alloy - 15
ferro-silicon (Si = 75%) - 0.8
ferro-manganese (Mn = 75%) - 0.5
cementitious - 0.4.

 The procedure for making the cast iron and pouring samples is similar to that of Example 1.

 The results of the tests are the following.

 Chemical composition of cast iron 96 mass: carbon - 3.04; silicon - 1.88; manganese - 0.88; phosphorus - 0.13; sulfur - 0.10; nickel - 0.76; chromium - 0.37 (Table 1).

 Tensile strength - 323 + 12 MPa.

 Hardness of the samples: with a diameter of 30.103m - 2.41 GPa, with a section of (120x200) .10 3m - 1.60 GPa.

 Microstructure of the iron in samples with a diameter of 30.10: metal matrix P, Pd 1.0, 1 gr = 123.10-6m; section of (120x200) 10-m: metal matrix P 85, Pd 1.4, Fe 15, lgr = 415.10 6m (Table 2).

 The examples given above show that the use for the preparation of cast iron of a cuprous pre-alloy, in comparison with the use of a chromium-nickel pre-alloy, makes it possible to obtain a matrix that is almost entirely pearlitic and has a higher hardness. cast iron in samples whose section is equal to (120x200) .10 3m. Such an improvement in the microstructure and the hardness of the cast iron makes it possible to substantially increase the wear resistance of the cast iron parts. In addition, the use of cuprous pre-alloy contributes to the improvement of the melt quasi-isotropy, which is confirmed by the data in Table 2 with respect to the hardness and quantity of perlite in the cast iron matrix ( Examples 8 to 15 and 16 to 18).

 Thus, the use of a cuprous pre-alloy makes it possible to develop cast iron parts for the construction of machine tools by ensuring that the required matrix (pearlitic) is obtained in the massive guides without forming white areas in them. walls and edges, whose thickness does not exceed almost 40.10- m.

Such a cuprous pre-alloy can be applied further to the manufacture of molded parts for hydraulic equipment working at pressures of 50 to 60 MPa. Table 1
Chemical composition of cast irons made using pre-alloys
Element Content of cast iron in elements (% by mass)
following the Examples.

1 2 3 4 5 6 7 8 1.Carbon 3.16 3.05 3.03 3.18 2.95 2.91 3.10 3.01 2.Silicon 1.82 1.95 2.05 1.94 1.98 2.10 1.78 1.84 3.Manganese 0.85 0.73 0.81 0.75 0.82 0.76 0.71 0.72 4.Phosphorus 0.12 0.15 0, 16 0.14 0.13 0.13 0.13 0.14 5.Suft 0.11 0.10 0.12 0.09 0.10 0.10 0.08 0.08 6. Nickel 0.20 0 , 0.48 0.34 0.67 0.99 0.34 0.68 7.Copper 0.05 0.11 0.16 0.07 0.14 0.22 0.21 0.42 8.Chrome 0.14 0.20 0.28 0.13 0.22 0.32 0.16 0.34 Table 1 continued
9 10 11 12 13 14 15 16 17 18 1. 2.94 2.96 2.98 3.02 3.23 2.93 2.97 3.20 3.17 3.04 2. 1.98 1.98 1.91 1.73 1.84 1.88 2.01 1.75 1.83 1.88 3. 0.89 0.86 0.78 0.88 0.91 0.78 0.85 0.91 0.88 0.88 4. 0.14 0.14 0.14 0.12 0.13 0.13 0.12 0.12 0.12 0.15 5. 0.10 0.11 0.10 0 , 08 0.09 0.09 0.10 0.08 0.10 0.11 6. 1.05 0.18 0.32 0.48 0.17 0.32 0.52 0.27 0.49 0 , 78 7. 0.65 0.33 0.70 1.05 0.35 0.71 1.09 - - 8. 0.48 0.15 0.31 0.45 0.18 0.33 0.51 0.16 0.25 0.37
Table 2
Mechanical properties and microstructure of the cast iron with introduction of pre-alloys in the load

<tb><SEP> Resistance <SEP> Hardness <SEP> in <SEP> OPa <SEP> Microstructure <SEP> of <SEP><SEP> Melt
<tb><SEP> to <SEP> the <SEP> trac- <SEP> on <SEP> exchange <SEP> in <SEP> of <SEP> samples
<tb><SEP> tion, MPa <SEP> tillon <SEP> from <SEP> to <SEP> diameter <SEP> from <SEP> 30.10
<tb><SEP>q><SEP>'m<SEP> (120x <SEP> Perlite <SEP> fer- <SEP> length
<tb><SEP> x200). <SEP> content <SEP> dtsper- <SEP> rite, <SEP> of <SEP> in
<tb><SEP> A <SEP> 103m <SEP><SEP> tene- <SEP> clusions
<tb> x
<tb> w <SEP> phite, x
<tb><SEP> 10-6m
<tb><SEP> 1 <SEP> 273- + 12 <SEP> 2.27 <SEP> 1.39 <SEP> P <SEP> 96 <SEP> Pd <SEP> 1.0 <SEP> Fe <SEP > 4 <SEP> 173
<tb><SEP> 2 <SEP> 305- + 15 <SEP> 2.23 <SEP> 1.52 <SEP> P <SEP> Pd <SEP> 1.0 <SEP> Fe <SEP> O <SEP > 165
<tb><SEP> 3 <SEP> 328- + 21 <SEP> 2.35 <SEP> 1.59 <SEP> P <SEP> Pd <SEP> 0.5 <SEP> Fe <SEP> 0 <SEP > 148
<tb><SEP> 4 <SEP> 279 + 13 <SEP> 2.41 <SE> 1.41 <SEP> SE <P <SEP> 1.0 <SEP><SEP> 160
<tb><SEP> 5 <SEP> 311-12 <SEP> 2.38 <SEP> 1.59 <SEP> P <SEP> Pd <SEP> 0.5 <SEP> n <SEP> 161
<tb><SEP> 6 <SEP> 326- + 18 <SEP> 2.36 <SE> 1.65 <SEP> P <SEP> Pd <SEP> 0.5 <SEP>"<SEP> 110
<tb> 7 <SEP> 281 + 16 <SEP> 2.38 <SE> 1.41 <SEP> P <SEP> Pd <SEP> 1.0 <SEP>"<SEP> 145
<tb><SEP> 8 <SEP> 331 + 11 <SEP> 2.29 <SEP> 1.69 <SEP> P <SEP> Pd <SEP> 0.5 <SE> w <SEP> 125
<tb><SEP> 9 <SEP> 353-15 <SE> 2.38 <SE> 1.83 <SEP> P <SEP> W <SEP> 0.3 <SEP> 95
<tb> 10 <SEP> 293 + 12 <SEP> 2.35 <SE> 1.49 <SEP> P <SEP> Pd <SEP> 1.0 <SEP>"<SEP> 128
<tb> 71 <SEP> 334 + 13 <SEP> 2.38 <SEP> 1.72 <SEP> P <SEP> Pd <SEP> 0.5 <SEP>"<SEP> 120
<tb> 12 <SEP> 351 + 14 <SEP> 2.38 <SEP> 1.85 <SEP> W <SEP> W <SEP> 0.3 <SEP> 95
<tb> 13 <SEP> 287 + 13 <SEP> 2.38 <SEP> 1.52 <SEP> W <SEP> W <SEP> 1.0 <SEP>"<SEP> 143
<tb> 14 <SEP> 33on + 13 <SEP> 2.35 <SEP> 1.75 <SEP> P <SEP> Pd <SEP> 0.5 <SEP>"<SEP> 103
<tb> 15 <SEP> 349t16 <SEP> 2.38 <SEP> 1.85 <SEP> P <SEP> Pd <SEP> 0.3 <SEP> n <SEP> 93
<tb> 16 <SEP> 268- + 16 <SEP> 2.38 <SEP> 1.41 <SEP> P <SEP> 96 <SEP> Pd-1.4 <SEP> Fe <SEP> 4 <SEP> 168
<tb> 17 <SEP> 29 <SEP> 18 <SEP> 2.35 <SEP> 1.52 <SEP> P <SEP> Pd <SEP> 1.0 <SEP> Fe <SEP> 0 <SEP> 143
<tb> 18 <SEP> 323- + 1? <SEP> 2.41 <SEP> 1.60 <SEP> P <SEP> - <SEP> Pd <SEP> 1.0 <SEP> Fe <SEP> 0 <SEP> 132
<Tb>
Table 2 (continued)
with section of (120x200) .10- m
perlite ferrite, length of content content inclusions of
graphite dispersity content,
x 10-6m 1 P 85 Pd 1.6 Fe 15 440 2 P 85 Pd 1.6 Fe 15 418 3 P 92 Pd 1.4 Fe 8 395 4 P 85 Pd 1.6 Fe 15 415 5 P 85 Pd 1, 4 Fe 15 403 6 P 92 Pd 1.4 Fe 8 385 7 P 85 Pd 1.6 Fe 15 435 8 P 92 Pd 1.0 Fe 8 385 9 P 96 Pd 1.0 Fe 4 365 10 P 92 Pd 1, 4 Fe 8 405 11 P 96 Pd 1.0 Fe 4 380.

 12 P 96 Pd 1.0 Fe 4 370 13 P 92 Pd 1.6 Fe 8 418 14 P 96 Pd 1.0 Fe 4 380 15 P 96 Pd 1.0 Fe 4 365 16 P 70 Pd 1.6 Fe 30 450 17 P 85 Pd 1.4 Fe 15 435 18 P 85 Pd 1.4 Fe 15 415

Claims (1)

 CLAIM  Pre-alloy for the production of cast iron parts, of the nickel-containing type, silicon, chromium, combat, carbon and iron, characterized in that it also comprises copper, the contents of pre-alloying constituents being the following ones (% in mass):  nickel 3 to 7  Silicon 3 to 7.5 ~  chrome 1 to 3  cobalt 0.2 to 0.5  carbon - 1 to 2.5  copper 1 to 7  iron the rest