SU1461609A1 - Solder for brazing cast iron - Google Patents

Abstract

The invention relates to brazing, in particular, to the composition of the solder used for brazing cast iron in the repair and sealing of iron castings. The purpose of the invention is to improve the wettability. Solder has the following composition, wt.%: Zinc 23,7-33,9; tin 1.0-1.4; manganese 6-8; nickel 4-6; aluminum 0.1-0.3; cadmium 8-10; antimony 0.6-0.8; hafnium 0.3-0.5; lanthanum 0.1-0.4; copper - the rest. Melting point: 815-830 ° C. Soldering is performed with ANSH-200 flux at a temperature of 5 minutes. The hardness of the HB of the weld metal is 182 udo. The strength of the solder joint when brazing the cast iron SChSch2 is 24 kgf / mm. The solder spreading area (solder weight 0.3 g, flux 1 g on average SC-12-28 cast iron, C17 64 SCh1TS2 - 67 mm H28L -86mm 4N15D7X2 - 74 mm o Solder melted in two stages. In the first stage, powders of copper, manganese, nickel, hafnium, tin, aluminum and lanthanum were fused in an alundum crucible, coated with paraffin to avoid oxidation, in argon 96% and hydrogen 4% and over 7 minutes, then it was cooled to fall asleep The melt was burnt, heated again in a furnace up to 1200 ° C without supplying a protective gas and quickly introduced cadmium and antimony, the melt was stirred and poured into a mold, and solder was used when sealing defects on cast iron. pump housings. 2 tabl, At Od

Description

one

The invention relates to brazing, in particular to the composition of solder for brazing iron, and can be used in the repair of articles of iron, as well as in the repair of defects in iron castings.

The aim of the invention is to improve the wettability.

Solder has the following composition, wt.%:

Zinc 23,7-33,9

Tin1.0-1.4

Manganese

Nickel

ALUMINUM

Cadmium

Antimony

Hafnium

Lanthanum

Copper

6-8

4-6 0.1-0.3

8-10

0.6-0.8

0.3-0.5

0.1-0.4

Rest

Melting point of solder 815-

Copper solder gives the necessary viscosity and strength, increases the temperature

melting and liquid flow If the copper content is less than 48%, the ductility of the seam decreases; if the content is more than 49%, the melting point of the solder increases

Tin improves the wettability of the metal to be soldered by solder, facilitates tinning, increases the fluidity of the solder, reduces the melting point. When the tin content is less than 1%, these effects do not manifest properly, and if the tin content is more than 1.4, solder embrittlement occurs.

Manganese increases the strength of the solder, improves the flowability of the solder on the soldered surface, helps to give the solder a color close to the color of cast iron. When the content of manganese is less than 6%, these effects are insufficient. When the content of manganese is more than 8%, the solder acquires a reddish color when exposed to air contact with air; its melting point rises.

Nickel, together with copper, increases the ductility of the weld seam, together with manganese contributes to the creation of white color and increases the strength of the weld metal. When the nickel content is less than 4%, the improvement of these properties is not achieved, and when the nickel content is more than 6%, the melting point of the alloy increases.

Aluminum serves to create a protective film on the surface of the welded joint, thereby preventing the oxidation of manganese. Aluminum reduces the solder melting teeture and increases the strength of the solder joint due to the formation of nickel aluminides. When the aluminum content is less than 0.1%, the strength of the solder joint does not increase, with a content of more than 0.3% 3, wetting with iron solder is successful.

Cadmium is used to improve the penetration of solder into the pores of cast iron, antimony, and lanthanum in order to improve the wetting of graphite with solder, while nafnium increases the adhesion of solder to cast iron.

Zinc, along with copper, is the main component that lowers the melting point of solder, improves its spreadability over the surface of cast iron,

Cadmium, together with zinc, tin and antimony, lowers the melting point of solder to increase its fluidity.

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molten solder helps

penetration of solder into the pores of the iron, which increases the strength of bonding of the solder to the iron and, consequently, the strength of the solder joint. Cadmium is an active metal, it improves the wettability by soldering the surface of the iron, as it is able to reduce oxides on the surface of the iron to metal by IQ. When its content is less than 8%, these effects do not fully manifest. 4 When the content of cadmium is more than 10%, no further improvement of the solder properties is observed.

Antimony, due to cadmium penetration into the gaps between graphite and the metal matrix, as well as into the pores 20 of graphite, promotes the wetting of graphite with solder due to the establishment of acceptor bonds. When the content of antimony is less than 0.6%, it slightly affects the properties of the solder. When the content of antimony is more than 0.8%, no further improvement in the properties of the solder is observed.

Hafnium, along with aluminum, contributes to the formation of an oxide film on the surface, which prevents its oxidation. In addition, the antimony wetting of graphite inclusions of cast iron is facilitated.

When the content of hafnium in the solder os is less than 0.3%, these effects appear weakly; if the content is more than 0.5%, the ductility of the solder decreases.

Lanthanum is a very active metal, contributes to the activation of the surface layer of the molten metal, improves the wetting of the iron surface with solder, improves the flowability of the solder on the surface of the iron, facilitates and accelerates the 45 lsg process. Lanthanum refines the solder grain during its crystallization, which improves the mechanical characteristics of the solder joint. When the content of lanthanum is less than 0.1%, its effect appears to be weak, and when the content is more. . 0.4% no further improvement in solder properties:

The solder is smelted from the available powders used to make 55 cored wires. Smelting was carried out in two stages.

In the first stage, in the alundum crucible, copper, manganese, nickel, and powders of tin and aluminum and lanthanum powders were mixed in the required proportions into the mixture as

no no

monolithic paraffin-coated piece to avoid oxidation. The crucible was placed in a preheated furnace, into which the gas mixture was fed,%: Ar 96, H, 2 4. After the crucible was heated to 1200 C, the crucible was held in the furnace for 7 minutes to dissolve the refractory components in the liquid alloy. Then the furnace was turned off and the alloy was cooled to increase the supply of protective gas. After the alloy was cooled, the crucible was removed from the furnace, the alloy surface was filled with crushed fused bur, the alloy was reheated to the shaft furnace without protective gas, and granulated zinc and then cadmium and antimony were injected, the melt was stirred with a tungsten rod. The crucible was removed from the furnace and the solder was poured into the mold, obtaining triangular rods.

Examples are soldered in Table 1.

The tests were carried out on samples of cast iron with dimensions of 50x50x6 mm of the following grades: gray medium frequency 12-28, alkali resistant SSF2, high silicon C-17, nirezist 4N15D Ux2, chromic H28L.

1 g of ANSh-20 flux and 0.3 g were applied to the ground surface of the sample.

4616096

The sample was placed in a muffle furnace and held at a temperature of 920 ° C for 8 minutes, after cooling, the area of solder spreading was measured. The test results are presented in table 2.

As can be seen from Table 2, the best properties, as well as the best spreading of 10 solders and wetting of the surface of the cast iron, are achieved with solders of compositions 2-4,

This solder was used for sealing defects on cast iron housings of pumps.

Claims (1)

Formula invented and Solder for the soldering of iron, containing 20 zinc, tin, manganese, nickel, aluminum, copper, and that, in order to improve the wettability, it additionally contains cadmium, antimony, hafnium and lanthanum 25 in the following ratio, wt.%: Zinc23-, 7-3 3.9 Tin1-1,4 Manganese6-8 30 Nickel4-6 Aluminum0,1-0,3 five Cadmium Antimony Haphniy Lantan Copper 8-10 0.6-0.8 0.3-0.5 0.1-0.4 Rest Table 1 59 76 79 eight 60 49 63 66 64 51 54 67 69 65 149 Table 2 61 73 76 74 58 170 176 182 188 186 18 22 24 26 26