RU2641590C2 - Powder wire - Google Patents

Abstract

FIELD: metallurgy.SUBSTANCE: powder wire comprises the following, wt %: steel shell 67.0-68.0, ferromanganese 4.00-8.00, ferrosilicon 1.90-3.40, ferrochrome 4.6-25.50, ferromolybdenum 0.50-2.60, ferrovanadium 0.06-0.5, nickel 0.05-1.00, cobalt 0.20-0.95, carbonfluorine-containing dust of aluminium production filters 0.70-6.95, iron - the rest.EFFECT: invention allows to increase the mechanical properties of the weld metal, prevent the formation of cold cracks in the process of welding, exclude pore formation and reduce the hydrogen content in the weld metal by introducing fluorine-containing components and creating additional gas protection, and reduce the cost of the welding process by optimizing the composition of the charge and efficient use of production wastes.2 tbl

Description

The invention relates to welding consumables and can be used for submerged arc surfacing to restore worn parts and obtain a wear-resistant protective coating on parts of mining equipment operating under conditions of abrasive wear, such as bins and tubules.

The composition of a flux-cored wire charge for open arc welding is known [1], containing ferrochrome, ferrotitanium, metal chromium, sodium silicofluoride, fluorspar, marble, boron carbide, cerium rare-earth fluorides / CeF ₃ , LaF ₃ , NdF ₃ , PrF ₃ , YF ₃ /, iron, nitrided ferromanganese, nickel, copper, aluminum, cobalt and graphite in the following ratio, wt. %:

Ferrochrome 22.0-25.0 Ferrovanadium 0.35-0.5 Ferrotitanium 0.8-1.0 Metal chrome 1.0-3.0 Sodium silicofluoride 1.0-2.0 Fluorspar 9.0-12.0 Marble 1.5-2.0 Nitrogenated Ferromanganese 0.35-0.45 Boron carbide 1.5-2.0 Nickel 1.0-3.0 Copper 0.3-1.0 Aluminum 1.0-1.5 Cobalt 1.0-3.0 Graphite 0.2-0.7 Rare earth metals fluorides of the cerium group 4.0-6.0 Iron rest

Significant disadvantages of this cored wire are:

- the high cost of cored wire through the use of expensive materials in significant quantities;

- low quality deposited metal due to pore formation associated with the use of marble and nitrated ferromanganese as components;

- reduced resistance of weld metal to abrasion.

Known [2] a flux-cored wire consisting of a steel shell and a powder mixture containing ferromanganese, ferrosilicon, ferrochrome, ferromolybdenum, ferrovanadium, graphite, sodium silicofluoride, ferro-tungsten, iron powder in the following ratio, wt. %:

Ferromanganese 0.2-0.5 Ferrosilicon 1.6-2.3 Ferrochrome 5.5-8.5 Ferromolybdenum 0.6-1.5 Ferrovanadium 1.0-3.0 Graphite 0.05-0.15 Sodium silicofluoride 2.2-2.4 Ferro-tungsten 5.0-8.5 Iron powder 5.0-15.0 Steel sheath rest

Significant disadvantages of this cored wire are:

- low quality deposited metal due to pore formation associated with a high hydrogen content;

- low toughness and resistance of weld metal to abrasion;

- the high cost of cored wire due to the use of expensive materials in significant quantities (ferro-tungsten and sodium silicofluoride).

Known as a prototype [3] is a flux-cored wire consisting of a steel sheath and a powder mixture containing ferromanganese, ferrosilicon, ferrochrome, ferromolybdenum, ferrovanadium, iron powder, carbon-containing dust from aluminum filters with a ratio of components, wt. %:

Steel sheath 67.0-68.0 Ferromanganese 0.50-1.20 Ferrosilicon 1.0-1.75 Ferrochrome 7.2-9.1 Ferromolybdenum 1.5-2.3 Ferrovanadium 0.6-0.8 Carbon fluoride dust filters aluminum production 0.70-1.20 Iron powder rest

Significant disadvantages of this cored wire are:

- low resistance of weld metal to abrasion and the possibility of cracking during operation;

- the high cost of the welding process through the use of expensive materials in significant quantities (tungsten and sodium silicofluoride).

The technical results of the invention are:

- improving the mechanical properties of the weld metal, in particular wear resistance and hardness due to changes in the chemical composition of the cored wire;

- preventing the formation of cold cracks in the surfacing process, eliminating pore formation and reducing the hydrogen content in the weld metal due to the introduction of fluorine-containing components and the creation of additional gas protection;

- reducing the cost of the welding process by optimizing the composition of the charge and the efficient use of production waste.

For this purpose, a flux-cored wire is proposed, consisting of a steel sheath and a powder mixture containing ferromanganese, ferrosilicon, ferrochrome, ferromolybdenum, ferrovanadium, carbon-containing dust of aluminum filters, iron powder, in which the powder mixture additionally contains nickel and cobalt in the ratio of components, wt. %:

Steel sheath 67.0-68.0 Ferromanganese 4.00-8.00 Ferrosilicon 1.90-3.40 Ferrochrome 4.6-25.50 Ferromolybdenum 0.50-2.60 Ferrovanadium 0.06-0.5 Nickel 0.05-1.00 Cobalt 0.20-0.95 Carbon fluoride dust filters aluminum production 0.70-6.95 Iron powder rest

The claimed limits are selected empirically, based on the quality of the metal obtained during surfacing, stability of the welding process, preventing the formation of cold cracks and obtaining the required mechanical properties.

Nickel and cobalt are additionally introduced into the mixture.

The introduction of the mixture of Nickel can significantly reduce the actual grain, significantly increase the work on abrasion without cracking and to increase the hardness of the deposited layer.

The introduction of cobalt into the mixture allows to increase the “adhesion” of the deposited layer and to exclude cracking during heating due to friction of the transported materials on the surface of the deposited layer.

Introduction to the composition of the flux-cored wire charge of an increased amount of carbon-fluorinated dust filters of aluminum production allows:

- increase the degree of hydrogen removal due to a complex of fluorine-containing compounds that decompose at welding process temperatures with the release of fluorine, which in turn interacts with hydrogen dissolved in steel to form gaseous compounds of the HF type;

- reduce the likelihood of pores and cold cracks in the weld metal by reducing the concentration of hydrogen in the weld metal;

- increase the concentration of carbon in the deposited layer due to intensive carburization during the interaction of carbon fluoride.

For the manufacture of a mixture of flux-cored wire used carbon-fluorine-containing dust filters of aluminum production with the following chemical composition, wt. %: Al ₂ O ₃ = 19-48; F = 17-28; Na ₂ O = 2.8-12; K ₂ O = 0.36-6.0, CaO = 0.6-1.8; SiO ₂ = 0.5-2.7; Fe ₂ O ₃ = 1.7-3.6; With _total = 22-30, MnO = 0.05-1.2, MgO = 0.06-0.87, S = 0.09-0.34, P = 0.09-0.15.

The change in the content of carbon-containing dust of aluminum filters in the composition of the inventive charge was carried out taking into account the production of high-quality deposited metal (good roll formation, dense weld metal without cracks, pores and non-metallic inclusions), while taking into account the content of other components that affect hardness, toughness and wear resistance obtained during surfacing of metal, as well as concentration of carbon obtained during surfacing.

In the manufacture of cored wire used: iron powder grade ПЖВ1 according to GOST 9849-86, nickel powder PNK-1L5 according to GOST 9722-97, cobalt powder PK-1U according to GOST 9721-79, carbon ferromanganese powder FMn 78 (A) according to GOST 4755- 91, FS 75 brand ferrosilicon powder in accordance with GOST 1415-93, high carbon ferrochrome powder of the ФХ900А brand in accordance with GOST 4757-91, ФМо60 grade ferromolybdenum powder in accordance with GOST 4759-91, ФВ50У0,6 ferrovanadium powder in accordance with GOST 27130-94.

The powders were mixed in a mixer and calcined to remove moisture at a temperature of (250-350) ° C. Next, carbon-fluorinated dust from aluminum filters was introduced into the composition. The manufacture of cored wire was carried out on the machine. The diameter of the finished wire after drawing operations was 3.6 mm, with a fill factor of 0.32. The flux-cored wire with the proposed charge was used for surfacing of steel plates from steel 3sp. Surfacing was performed under the AN-20 flux using an ASAW-1250 welding tractor.

The presence of cracks in the surfacing process was evaluated visually, quality control was carried out by the ultrasonic method, as well as using metallographic sections cut from samples. The hydrogen content in the deposited metal was determined on a gas analyzer company "LECO" TC-600 (USA). Hydrogen content was varied in the range (0.2-0.6) cm ^3/100 g of weld metal with an acceptable hydrogen content in the high alloy weld metal to 2 cm ³ / 100g metal. The hardness of the deposited metal was monitored immediately after surfacing. The hardness of the deposited metal after surfacing was 42-48HRC. Defects (cracks, pores and non-metallic inclusions) during surfacing with flux-cored wire with a charge of the claimed composition containing dust from aluminum electrostatic precipitators were not detected. After the deposition of the rollers onto the plates, the samples were cut and abrasion tested on the 2070 SMT-1 machine.

We studied 5 options for the composition of the charge (table 1) cored wire with foreign and claimed limits.

The effect of changes in the chemical composition on the technological properties and mechanical characteristics of the weld metal is shown in table 2. Using the inventive composition of the flux-cored wire charge in comparison with the base composition (prototype) allows:

1. To improve the quality of the deposited metal by reducing its contamination with non-metallic inclusions, reduce the likelihood of pore formation and prevent the formation of cold cracks.

2. Reduce the hydrogen content by the introduction of fluorine-containing components and create an extra gas protection in the average of 0.2-0.6 cm ³ / 100g metal.

3. Increase the hardness of the weld metal to 42-48 HRC.

4. To reduce the cost of manufacturing flux-cored wire by reducing the content of alloying components and the use of aluminum waste in the proposed flux-cored wire.

List of sources

1. A.S. USSR No. 1657320, B23K 35/36.

2. A.S. USSR No. 287830, class B23K 35/30, B23K 35/04.

3. Pat of the Russian Federation No. 2518035, cl. B23K 35/368.

Claims (2)

A flux-cored wire, consisting of a steel shell and a powdery mixture containing ferromanganese, ferrosilicon, ferrochrome, ferromolybdenum, ferrovanadium, carbon-containing dust of aluminum filters and iron, characterized in that the mixture additionally contains nickel and cobalt powder in the following ratio of components, wt. %: steel sheath 67.0-68.0 ferromanganese 4.00-8.00 ferrosilicon 1.90-3.40 ferrochrome 4.6-25.50 ferromolybdenum 0.50-2.60 ferrovanadium 0.06-0.5 nickel 0.05-1.00 cobalt 0.20-0.95 carbon fluoride dust filters aluminum production 0.70-6.95 iron rest