RU2397853C1 - Electrode for manual arc welding - Google Patents

Abstract

FIELD: instrument making. ^ SUBSTANCE: invention may be used for manual arc welding of high-alloy heat-proof steels with chromium and nickel content not exceeding 26% and 20%, respectively. Proposed electrode consists of high-alloy-steel rod with a coat applied thereon and containing the following substances, wt %: marble - 7-22, ferrosilicon - up to 10, ferromanganese or manganese - 4-12, ferrochromium or chromium - 4-15, potassium chromate - 0.5-5.0, titanium dioxide making the rest. In compliance with this invention, said coat additionally comprises, wt %: ferroniobium - up to 10 and/or ferrotitanium - 2-10. The coat may additionally contain at least one component selected from the group comprising, wt %: hematite - up to 10, dolomite - 3-10, feldspar - 3-10, fluor spar - 4-10, iron powder - 2-13 and soda - up to 3. Titanium dioxide in coat is represented by rutile and/or pure titanium dioxide. Titanium dioxide-to-marble ratio is smaller than or equal to 1.5-2.5. electrode rod is made from wire "-04Ñ199" or "-07Ñ188ô2æ", or "-04Ñ1911£". Potassium bichromate facilitates producing geometrically perfect welded seam shape. ^ EFFECT: electrode allows welding by both DC and AC, reduced pore formation, ease of arc ignition and slag separation. ^ 6 cl, 3 tbl

Description

The invention relates to welding materials and can be used for manual arc welding of high alloy heat-resistant and heat-resistant steels with a chromium content of up to 26% and nickel up to 20%.

For welding the above-mentioned steels, mainly electrodes with a basic coating are used, i.e. based on marble-fluorspar - see, for example, SU 804308 A1, 02.15.1981 / 1 /. Such electrodes are characterized by low technological maneuverability when performing welding due to insufficient stability and elasticity of the arc due to the low emissivity of the coating and slag. The unstable melting of the electrode, in turn, contributes to a spontaneous change in the nature of the transfer of electrode metal through the arc gap, for example, from medium-droplet to coarse-droplet, which causes unsatisfactory formation of the weld and its surface, as well as a decrease in the separability of slag, especially from narrow and deep grooves. In addition, these electrodes allow welding only by direct current.

To some extent, these disadvantages can be eliminated by the use of electrodes with rutile, rutilebasic or rutilovokisly coating.

The closest analogue (prototype) of the proposed electrode is a coated electrode for manual arc welding in accordance with RU 2248869 C1, 03/27/2005 / 2 /. The electrode / 2 / consists of a rod of austenitic steel and a coating containing, wt.%: Marble 10-28, ferromanganese or manganese 6-15, ferrosilicon 1-9, ferrochrome or chromium 5-20, magnesite 3-12, iron powder 2-10, titanium dioxide - the rest. The electrode allows welding with both direct and alternating current. Its disadvantage can be recognized as a certain tendency to pore formation in the deposited metal, due to the crystallization moisture of the coating, which is difficult to remove by calcining such electrodes.

The objective of the invention is the creation of electrodes for welding the above group of steels, devoid of the above disadvantages.

The technical result provided by the solution of this problem is to obtain an electrode that allows welding with both alternating and direct current, having high resistance to pore formation in the deposited metal, as well as light arc ignition, incl. repeated, and easy separability of slag up to spontaneous.

The problem is solved in that in the electrode for manual arc welding of high alloy steels and alloys on an iron-nickel and nickel basis, consisting of a rod of high alloy steel and a coating deposited on it containing marble, ferrosilicon, ferromanganese or manganese, ferrochrome or chromium, titanium dioxide, the coating additionally contains potassium chromate in the following components, wt.%:

Marble 7-22 Ferrosilicon to 10 Ferromanganese or manganese 4-12 Ferrochrome or chrome 4-15 Potassium Chromate 0.5-5.0 Titanium dioxide rest.

In addition, the coating may additionally contain at least one component selected from the group comprising, wt.%: Ferroniobium up to 10, ferrotitanium 2-10, hematite up to 10, dolomite 3-10, iron powder 2-13 , fluorspar 4-10, feldspar 3-10, soda - up to 3. The ratio of titanium dioxide to marble is less than or equal to 1.5-2.5.

As titanium dioxide, the coating may contain rutile and / or pure titanium dioxide.

The electrode rod can be made of wire of the grades Sv-04X19N9 or Sv-04X18H8G2B, or Sv-04X19N11M.

All coating components are selected so that it matches the rutile or rutile basic form. The presence of titanium dioxide in the coating in the indicated ratio provides the possibility of welding with alternating current, and the accepted fraction of fluorspar provides focusing of the arc and, providing stability of the arc discharge, contributes to the formation of a geometrically perfect shape of the weld, while not excluding the possibility of direct current welding.

Potassium chromate (chrompeak) - KCr ₂ O ₃ , being a very active material, significantly affects the interfacial interaction of the coating ingredients forming slag (in the general case, marble, fluorspar). Chrompeak affects the surface tension between the slag and metal droplets transferred from the end of the electrode into the weld pool. In addition, chrompeak affects the shape of the slag, the regulation of its amount allows the formation of slag from a uniform thickness along the perimeter of the seam to crescent, which is characterized by the easiest separability of the slag.

Manganese (or ferromanganese) improves the mechanical properties of the weld at room and elevated temperatures. The combined introduction into the coating of such components as ferromanganese or manganese, ferrosilicon and iron powder in the proposed quantities, allows you to adjust a wide range of chemical composition, thermal and mechanical properties of the weld, as well as the structure of the weld metal.

Ferrosilicon and ferrotitanium provide deep deoxidation of the deposited metal and reduce the tendency to aging.

The introduction of such components as ferroniobium and ferrotitanium into the coating is not mandatory in all cases of the invention, but depends on the basic composition of the welding wire, as well as on the requirements for the physicochemical and functional characteristics of the deposited metal.

Components from the group consisting of dolomite, feldspar, fluorspar, hematite and soda are also not mandatory in all cases of using the invention and are introduced to regulate the welding and technological properties of the electrode (increase arc stability, improve slag separation, form a weld and its dimensions, etc.) or to control the nature of the transfer of molten metal into the weld pool due to a change in surface tension in the slag-metal system during electrode melting. The introduction of dolomite and hematite affects the surface properties of the slag, which are manifested both in the transfer of metal to the weld pool and in the formation of the weld. Iron powder allows you to adjust the activity of the coating and slag during arc burning.

As titanium dioxide, rutile or pure titanium dioxide can be used. These materials can also be used together.

The invention is implemented as follows.

For the manufacture of electrodes used rods of austenitic wire Sv-04Kh19N9, or Sv-07Kh18N8G2B, or Sv-04Kh19N11M. All coating components were ground, and then mixed with a binder, which was used as sodium or potassium-sodium liquid glass.

The coating compositions of the electrodes, including the ingredients in the proposed ratio, are given in table 1: examples 1,2 - on the wire Sv-04X19H9, example 3 - on the wire Sv-07X18H8G2B, and example 4 - on the wire Sv-04X19H11M.

The electrodes were made by crimping, and then they were dried and calcined at a temperature of 280-300 ° С for 1 h.

Testing of the electrodes was carried out as follows. The electrodes welded plates of steel 12X18H9 with a thickness of 20 mm, from which samples were made for mechanical testing and chemical analysis of the deposited metal.

In the process of welding butt joints, the following technological features of the electrodes were identified:

- stable arc burning during welding with both direct and alternating current;

- light ignition and easy reignition of the arc;

- insignificant (up to 1.5%) loss of electrode metal by spraying;

- very easy, and in many cases spontaneous, separability of the slag, including from the cutting of the butt joint;

- good formation of a symmetrical weld with a finely scaly surface during welding in all spatial positions (except vertical from top to bottom).

Table 1 shows the composition of the coatings, taking into account the need for delegation of the weld metal or additional alloying with elements that are not provided for by the basic composition of the wire.

Table 2 shows the mechanical properties of the deposited metal obtained using the compositions of table 1, and in table 3 - the corresponding chemical composition of the deposited metal.

Table 1. Coating components Coating Composition Number one 2 3 four Marble 17 13 twenty 22 Fluorspar 6 8 6.5 10 Rutile 17 12 32 - Titanium dioxide 12 21 - 32 Hematite 10 5 3 - Ferrochrome 8 8 7 7 Feldspar 5 9 3 10 Potassium Chromate 1,5 2.0 2.5 four Ferrotitanium 3,5 2 four four Ferromanganese 4,5 5 four four Ferroniobium 4,5 5 2 2 Dolomite 3 - four - Soda - 1,5 2 2 Iron powder - 3,5 8 - Ferrosilicon 8 5 2 3

table 2 No. of coating composition Temporary tear resistance, MPa Mechanical properties Relative extension, % Impact strength, J / cm ² one 576 32.6 149 2 604 30.1 132 3 597 33.7 161 four 611 31.8 129

Table 3 No. of coating composition The chemical composition of the weld metal,% FROM Si Mn Ni Cr Nb S R 12 0,07 0.71 1.4 9.0 20.5 - 0.012 0.019 3 0.09 0.58 1.3 9.2 18.7 1.10 0.017 0.017 four 0,045 0.49 1,2 10.95 20,0 Mo / 1.17 0.019 0.017

Claims (6)

1. An electrode for manual arc welding of high-alloy heat-resistant and corrosion-resistant steels, including an austenitic steel core and a coating on it containing marble, ferrosilicon, ferromanganese or manganese, ferrochrome or chromium, titanium dioxide, characterized in that the coating additionally contains chromium -acid potassium in the following components, wt.%:
Marble 7-22 Ferrosilicon To 10 Ferromanganese or manganese 4-12 Ferrochrome or chrome 4-15 Chromic Acid Potassium 0.5-5.0 Titanium dioxide Rest 2. The electrode according to claim 1, characterized in that the coating additionally contains, wt.%: Ferroniobium up to 10 and / or ferrotitanium 2-10. 3. The electrode according to claim 1 or 2, characterized in that the coating additionally contains at least one component selected from the group comprising, wt.%: Hematite up to 10, dolomite 3-10, feldspar 3-10, fluorspar 4-10, iron powder 2-13, soda up to 3. 4. The electrode according to claim 1, characterized in that as the titanium dioxide coating contains rutile and / or pure titanium dioxide. 5. The electrode according to claim 1, characterized in that the ratio of the content of titanium dioxide to marble is less than or equal to 1.5-2.5. 6. The electrode according to claim 1, characterized in that the rod is made of austenitic steel wire Sv-04X19H9, or Sv-07X18N8G2B, or Sv-04X19N11M.