SU1252104A1 - Electrode coating composition - Google Patents

Description

The invention relates to arc fusion welding and can be used in welding, mainly repair, of structures made of metal, which is exposed during operation to corrosive media that cause corrosion, oxidation of the metal and its saturation with sulfur.

The aim of the invention is to increase the resistance of the weld metal against the formation of pores and hot cracks by improving the desulfurization ability of the electrode coating when welding steels with a high sulfur content in the surface layer (up to 0.05-0.15%) and the presence of rust and scale on the surface. .

Ensuring high resistance against the formation of pores and hot cracks in the weld metal and reducing the sulfur content in it is achieved by introducing barium-containing glass, since barium is characterized by high thermodynamic affinity for sulfur, which leads to a decrease in its content in the weld, as well as barium-containing glass 1-3 wt.% Dramatically improves the wettability of the slag with the pressure of the metal of the weld pool. The latter leads to an increase in the metallurgical treatment of the weld pool and, as a consequence, a decrease in the metal's tendency to porosity and hot cracks. The main factor driving them to improve the wettability of the weld metal with slag is the transition to the slag compound from the barium oxide coating contained in barium-containing glass. To improve the technological properties of the coating mass, the composition of the electrode coating also contains synthetic mica in the amount of 4-6 wt.%.

Barium has the highest chemical affinity for oxygen and sulfur as compared with the known acidifying agents (Mn, Si, Ti); therefore, as a result of the metallurgical reactions, oxysulfides and sulfides are formed (depending on the activity and concentration of barium), which then removed to the putty.

The barium sulphide remaining in the weld metal has a globular shape and is distributed in a finely dispersed form fairly uniformly and does not form fusible eutectics. Thus, the introduction of; barium in barium

five

0

five

0

containing glass into the electrode coating allows for improved desulfurization ability of the coating. By crushing the metal structure and changing the morphology of non-metallic inclusions, barium contributes to an increase in the performance characteristics of the weld metal, in particular plasticity and toughness.

Along with the grinding of the structure, cleaning the grain boundaries from harmful impurities, increased density and plastic properties of the barium metal also has a low electron work function, which ensures high stability of the AC arc. Due to the increased affinity of bari for oxygen, welding on a long arc is possible without the formation of pores in the weld metal.

It was established experimentally that the required combination of electrode properties (high resistance of the deposited metal to hot cracking in the complete absence of defects such as pores and fistulas when welding rusty and oxidized metal and favorable welding and technological characteristics of the coating) is achieved when barium-containing glass is in the range 1-3 wt.%.

In tab. Figure 1 shows examples of electrode coating compositions.

Table 1

Ferromanganese

Ferrosilicon Ferrotitanium

Barium-containing glass Mica synthetic

Iron powder

one

four

40

2 5

31

3 6

23

According to the mechanical properties of the weld metal, the electrodes with the proposed coating are of type 350 and provide a fairly high value. I. Shulla editor

Compiled by N. Ivanov Tehred V. Kadar

Order 4569/15 Circulation 1001 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

Table 5

neither the toughness of the welds, nor the high resistance of the weld metal, to the formation of hot cracks and pores.

Proofreader S. Shekmar

Claims (2)

1. COMPOSITION OF ELECTRODE COATING, containing marble, fluorspar, ferrosilicon, ferromanganese, ferrotitanium, iron powder, characterized in that, in order to increase the resistance of the weld metal against the formation of pores and hot cracks by improving the desulfurization ability of the coating when welding steels with a high content sulfur in the surface layer (up to 0.05-0.15 Z) and the presence of rust and scale, the composition additionally contains barium-containing glass and water in the following ratio of components, Mac.Z: Marble 30-34 Fluorspar 18-22 Ferrosilicon 3-4.5 Ferromanganese 1-2,5 Ferrotitanium 3-5 Barium-containing glass 1-3 Mica 4-6 Iron powder Rest In this case, barium-containing glass has the following composition, wt. X: SiO _? 67.5 * 0.5; Na ₂ 0 7 ± 0.8; ACO * 5 + 0.5; K ₂ 0 7 * 0.7; BaO 12 + 0.6; F 0.6 * 0.2; oxides Fe, Ca and Mg the rest. 2. The composition according to claim 1, characterized in that the waste barium glass used for the manufacture of picture tubes is taken as barium-containing glass.