RU2268128C1 - Electrode for welding high-strength steels of pearlite and austenite classes - Google Patents

Abstract

FIELD: manufacture of electrodes for welding high-strength different-class steels including austenite manganese steels.

SUBSTANCE: metallic rod is formed of steel of kind given in description of invention. Coating contains next relation of components, mass %: marble, 34.0 -49.0; fluorspar, 28.0 -45.0; quartz sand, 3.0 - 5.0; ferrotitanium, 3.0 - 8.0; ferrosilicon, 2.0 - 5.0; metallic manganese, 2.0 -8.0; ferrovanadium, 2.0 - 6.0; sodium liquid glass (relative to mass of dry mixture),23.0 - 28.0.

EFFECT: enhanced strength properties of seam metal, lowered trend to hot cracking, pore formation, good separation of slag skin.

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Description

The invention relates to the field of production of welding materials and can be used in various industries for welding high strength steels of various classes.

Of the known electrodes used for this purpose in the relevant industries, the closest to the application electrode for the purpose and composition of the coating components is an EA-981/15 electrode ("Electrodes for the arc welding of steels and nickel alloys", I.A. Zaks, Publishing House of St. Petersburg: "WELCOME", 1996, p. 342, 343), consisting of a core - wire grade EI-981 (Sv-09X16H25M6AF) and an electrode coating containing in wt.%:

Marble 49 Fluorspar 26 Manganese metal 6 Ferrotitanium 5 Titanium dioxide 6 Ferrosilicon four Marmot iron 2 Ferrovanadium four Sodium water glass (to the mass of the dry mixture) 23-30

The main disadvantage of these electrodes is the insufficiently high strength characteristics of the obtained weld metal, its increased tendency to pore formation during welding in the ceiling position, as well as hot cracks in the root passages, and poor separability of the slag crust during welding of austenitic manganese steels.

The technical result is the creation of an electrode for welding high-strength steels of pearlite and austenitic class, providing higher strength properties of the weld metal, low tendency to the formation of hot cracks, pores in the root passages and good separability of the slag crust when welding all types of high-strength steels, including austenitic manganese steels.

The technical result is achieved by the fact that the electrode of the EA-868/20 brand consists of a metal rod - a wire and an electrode coating containing marble, fluorspar, ferrotitanium, ferrosilicon, metallic manganese, ferrovanadium. According to the invention, the core is made of steel grade 10X19H23G2M5FAT, and the coating additionally contains quartz sand in the following ratio of components, wt.%:

Marble 34.0-49.0 Fluorspar 28.0-45.0 Quartz sand 3.0-5.0 Ferrotitanium 3.0-8.0 Ferrosilicon 2.0-5.0 Manganese metal 2.0-8.0 Ferrovanadium 2.0-6.0 Sodium water glass (to the mass of the dry mixture) 23.0-28.0

moreover, EP-868 (Sv-10X19N23G2M5FAT) wire is used as a rod.

This ratio of components in the electrode coating and the alloyed rod of wire EP-868 allows you to obtain electrodes that provide: high stability of arc burning, spontaneous separability of the slag crust when welding pearlitic and austenitic manganese steels, low tendency to hot cracks, lack of pores and high strength properties of the weld metal.

The increase in welding and technological characteristics and the decrease in the tendency of weld metal to porosity is explained by the replacement of titanium dioxide with quartz sand in the coating. The use of titanium dioxide in the coating during welding of manganese austenitic steels leads to the formation of spinels, which impede the separability of the slag crust.

The established alloying of the weld metal allows one to obtain high strength characteristics of the weld metal — yield strength of at least 560 MPa, tensile strength of at least 800 MPa and low magnetic permeability μ≤1.01 of weld metal. The obtained high strength characteristics of the weld metal can reduce the consumption of welding electrodes, in comparison with electrodes of the EA-981/15 grade, by 10-15%.

A set of laboratory and pilot industrial works was carried out on the manufacture, testing, and practical testing of electrodes for welding high-strength steels of pearlite and austenitic classes, including high-strength pure austenitic nitrogen manganese steels. The manufacture of the metal core included the smelting of ingots from steel grade 10X19H23G2M5FAT, the chemical composition is shown in Table 1, of which a metal rod ⌀ 4 mm was obtained by forging, followed by rolling and drawing.

The electrodes were made in pilot production at the installation for the production of coated electrodes of the Swiss company Oerlikon.

The prototypes of the electrodes were tested on high strength low alloy and austenitic manganese steels. Welding was carried out with direct current of reverse polarity without preheating. The welding modes were as follows: Isv. = 140-160 A, Ud = 22-26 B, the position of the seam is lower. The inter-pass temperature was not more than 100 ° C.

Visual inspection and radiographic inspection of the weld metal showed the absence of unacceptable defects: cracks, lack of penetration, burn-throughs, large non-metallic inclusions.

Of the weld metal obtained by using electrodes of the proposed and known compositions, samples were made and tested to determine the chemical composition and mechanical properties.

The chemical composition of the coatings of the proposed and known welding electrode is presented in table 2. Data on comparative tests of mechanical properties are presented in table 3. Technical and economic efficiency from the use of the invention is expressed in increasing the reliability and durability of products welded with these electrodes, by increasing the strength of the weld metal and reducing the tendency of the metal to form hot cracks.

Table 1
The chemical composition of steel grade 10X19H23G2M5FAT FROM Si Mn Cr Ni Mo Ti S P V N ₂ Fe 0.08
0.12 Nb
0.4 1,5
2,5 18.0
20,0 22.0
24.0 4,5
5.8 0.20
0.45 Nb
0.015 Nb
0,020 1,0
1.3 0.20
0.35 Ost. table 2
The chemical composition of the coatings of the known and claimed electrodes Structure No. The composition of the coating, wt.% Fluorspar Quartz sand Titanium dioxide Ferrotitanium Ferrosilicon Manganese met. Surik Ferrovanadium Marble Liquid glass The claimed one 45 5 - 3 5 2 - 6 34 23 2 37 four - 5 3 5 - four 42 25 3 28 3 - 8 2 8 - 2 49 28 Izv. four 26 - 6 5 four 6 2 four 47 28-30 Table 3
The results of comparative tests of electrodes Structure No. Weld metal characteristics The number of pores per 100 mm St. seam. Ceiling position Swar. Separation of the slag crust,% (manganese. Austenite. Art.) Yield Strength, MPa Tensile strength, MPa Rel elongation,% KV stroke work, J T = 20 ° C T = -40 ° C The claimed one 575 798 32 68 65 Ots. Chorus. (100%) 2 587 805 32 74 63 Ots. Chorus. (100%) 3 592 807 31 72 66 Ots. Chorus. (100%) Izv. four 530 750 32 74 68 3 Ned. (fifteen%) Note - The data are averaged over the results of testing three samples at one point.

The results of comparative tests show that the claimed composition in comparison with the known provides the weld with higher strength characteristics, low tendency to the formation of pores and hot cracks. In addition, the claimed electrode ensures the absence of burns on the weld when welding austenitic manganese steels.

Claims (1)

An electrode for welding high-strength steels of pearlitic and austenitic class, consisting of a metal rod and a coating containing marble, fluorspar, ferrotitanium, ferrosilicon, metal manganese, ferrovanadium and liquid glass, characterized in that the metal rod is made of steel 10Kh19N23G2M5FAT (EP-868 ), and the electrode coating additionally contains quartz sand in the following ratio of components, wt.%: Marble 34.0-49.0 Fluorspar 28.0-45.0 Quartz sand 3.0-5.0 Ferrotitanium 3.0-8.0 Ferrosilicon 2.0-5.0 Manganese metal 2.0-8.0 Ferrovanadium 2.0-6.0 Sodium water glass (to the mass of the dry mixture) 23.0-28.0