CS257124B1 - Treatment method for covering material of covered electrods for welding - Google Patents

Abstract

The solution relates to the method of packaging treatment mass of coated electrodes for welding steels by electric arc acting by frequency oscillations. Packing material ready for steel core pressing before pressing it vibrates by frequency oscillations ranging from 10 to 120 Hz for a period of time 1 to 10 minutes. This achieves high resistance to electrode wetting.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of treating a casing mass of coated electrodes for electric arc welding of steels by applying frequency oscillations.

The welding electrode sheath is produced by pressing the sheathing material onto the electrode core. The packaging mass is prepared by kneading or mixing a dry, homogeneous mixture of selected non-metallic powdered materials such as limestone, fluorspar, rutile and metal such as ferro-manganese, ferro-silicon, iron powder and the like with waterglass as binders to achieve plastic consistency of the kneaded mass.

The coated electrodes thus produced typically exhibit a tendency to become wet when exposed to ambient air. Their packaging receives moisture, or water from the air, when the relative humidity is reasonably high. However, the wetted electrodes exhibit deteriorated technological and metallurgical properties, for example, give porous welds, have large spatter during welding, supply large amounts of hydrogen to the weld metal, and the like.

Several modes of protection are used against this affection. For example, special substances are added to the packaging composition to prevent water vapor from entering the interior of the package, or special substances are added to the waterglass which reduce the ability of the dried waterglass in the dried electrode to receive water, or the electrodes cover a thin layer of a protective agent to prevent water vapor from entering the package surface. Further, it is known to store dried electrodes in hermetically sealed sheet metal hand held containers until they are consumed at the workplace.

While the above compositions provide some protection to the coated electrodes from humidity contained in the atmosphere, their use is associated with considerable disadvantages. The addition of different materials to the packaging composition or to the waterglass reduces the plastic properties of the packaging composition. Coating the finished electrodes with protective layers is laborious.

In accordance with the invention, these disadvantages are largely eliminated. The essence of the coating of coated electrodes for welding and welding of steels by electric arc consists in that the coating composition is vibrated at a frequency of oscillations from 10 to 120 Hz in a time from 1 to 10 minutes before its pressing.

An advantage of the method of treating the coated electrode sheath for welding according to the invention is that a relatively long high wetting resistance of the electrode sheath is achieved, which represents a significant improvement in the technological properties, while avoiding the need for much more costly electrode protection methods.

• The adjustment method is explained in more detail in the following examples.

Example 1 1

A base electrode sheath of strength class 440 MPa prepared by kneading the initial homogeneous dry mixture with potassium water glass was placed in a vessel at 10 kg. This can was placed on the vibrator table of the vibrator and fixed to it. The vibration was performed at 60 Hz and 8,000 duty cycles were performed, which took 2.2 minutes. The mass was then pressed onto the steel core of the electrode. In order to compare the properties, a packaging material of the same grade was pressed, prepared by the same kneading technology, but not vibrated. After drying the electrodes at 200 and 350 ° C for two hours, both electrodes were subjected to the moisture test under the same conditions. The electrodes were placed in a humidifying chamber at a temperature of 20 ° C and a relative humidity of the chamber of 84%. Even after 6 hours of residence of the tested electrodes in the humidification chamber, large differences in electrode wetting were detected by the gravimetric method. An electrode made by crimping an unvibrated coating composition showed a wetting of 1.35% by weight, while the same vibrationally treated composition of the invention gave the coating such a high moisture resistance that its moisture content was only 0.45% by weight. Example # 2

In addition, tests were conducted on the effect of vibration time and vibration frequency on the wettability of the same electrode sheath as in Example 1. 1. The coating composition was vibrated at 120 Hz for 4.8 minutes after treatment with potassium waterglass to determine a moisture content of 0.41% by weight. Example # 3

When vibrating the same packaging material as in Example no. 1 at 10 Hz, the mass was vibrated for 10 minutes. The moisture content of the coating composition was found to be 0.49% by weight.

The method of treatment of the packaging material according to the invention can be used in the manufacture of coated welding electrodes, in particular for manual arc welding of steels.

Claims (1)

A method of treating a coating material of a coated electrode for welding and welding an arc by steel, SUMMARY OF THE INVENTION The packaging material is vibrated at a frequency of from 10 to 120 Hz for 1 to 10 minutes prior to compression.