MR – 3
Permissible spatial positions during welding
MR – 3 Welding Electrodes
Electrodes for welding of carbon and low alloy steels
Prices for welding electrodes
Type of coverage
Rutile oil.
Current and polarity
Direct current of any polarity (reverse “+” on the electrode is recommended) and alternating current from a transformer with an open-circuit voltage of at least 50-70 V.
Surfacing coefficient
8.0 – 9.0 g/ah
Consumption of electrodes
~ 1.7 kg per 1 kg of deposited metal
Application Area. MR – 3 Welding Electrodes.
MR-3 are universal electrodes for welding critical structures made of low-carbon and low-alloy steels with a tensile strength of up to 490 MPa (with a carbon content of up to 0.25%):
• Construction and installation: welding of metal structures, building frames, critical components.
• Pipelines: welding of gas and water pipelines, including fixed-position joints.
• Mechanical engineering and shipbuilding: manufacturing of frames, hull structures, pressure vessels.
Welding Technique. MR – 3 Welding Electrodes.
A short arc is mandatory. A long arc leads to oxidation, porosity, and deterioration of mechanical properties. Mandatory baking: Before use, the electrodes require baking to remove moisture from the coating, which is critical for low-hydrogen electrodes.
Regulatory Documents. MR – 3 Welding Electrodes.
GOST 9466-75, GOST 9467-75.
Corresponding International Standard.
E 430 (3) – R60
Special Properties. MR – 3 Welding Electrodes.
Not prone to crack formation and porosity. They have excellent welding and technological properties: easy initial and re-striking, stable arc burning, low spatter, easy slag removal.
Chemical Composition of Deposited Metal, %
| C | Si | Mn | P | S | |
| Typical Value | 0.10-0.12 | 0.09-0.35 | 0.35-0.70 | ≤0.030-0.040 | ≤0.035-0.045 |
Welding Recommendations (Current, A)
| Diameter, mm | Weld Position | ||
| Flat | Vertical | Overhead | |
| 2.0 | 50-80 | 40-60 | 40-60 |
| 2.5 | 60-90 | 50-80 | 50-80 |
| 3.0 | 70-100 | 60-90 | 60-90 |
| 4.0 | 100-150 | 90-140 | 90-140 |
| 5.0 | 150-200 | 140-180 | not recommended |
| 6.0 | modes are selected individually, typically from 220 A | ||
We respond quickly to questions on Telegram
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Bottom horizontal or in a boat
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Bottom to the corner
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Horizontal seam on a vertical plane
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Vertical seam for lifting
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Vertical seam for descent
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Ceiling seam
All covered electrodes are sensitive to moisture absorption. Excessive moisture content in the coating can lead to porosity or hydrogen cracking.
However, if the climatic storage conditions meet the following requirements, moisture absorption by the electrodes is minimal:
• 5–15°C at a maximum relative humidity of 60%
• 15–25°C at a maximum relative humidity of 50%
• >25°C at a maximum relative humidity of 40%
At lower temperatures, maintaining the storage temperature 10°C above the ambient temperature is sufficient to achieve the required moisture content level. Cold packages must be allowed to warm up to ambient temperature before opening.
At higher temperatures, the required moisture content in the air can be achieved by dehumidification. The shelf life of electrodes under the above conditions shall not exceed three years.
• Covered electrodes with a basic coating and low hydrogen content must be baked prior to each use whenever requirements regarding the content of diffusible hydrogen and/or the soundness of the deposited metal are specified.
• Stainless steel electrodes with a basic coating may produce porosity during welding if the humidity levels during their storage did not meet the requirements. To restore their original properties, they also need to be baked.
• Electrodes for welding carbon steels with a cellulosic or rutile coating typically do not require baking.
• Electrodes that have suffered serious damage due to exposure to moisture cannot be restored by rebaking and must be rejected.
Contacts
Company phone numbers:
+375 (29) 688-27-06
+375 (17) 388-28-02 accountant
+375 (17) 388-28-03 sales department
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