SU1609568A1 - Method of electric arc machining - Google Patents

Abstract

The invention relates to welding and surfacing, in particular to surfacing with strip electrodes, and can be used in the application of coatings with special properties on the working surfaces of products in various fields of engineering, for example, in anticorrosive surfacing of internal surfaces of an atomic energy equipment. The purpose of the invention is to improve the quality of the deposited layer by aligning the heat input across the width of the weld pool. Pulsed voltage pulses of equal duration but different amplitude, or pulses of equal amplitude but of different duration, simultaneously synchronize the sections of a tape electrode with a width of 0.15-0.2, and pulses of greater amplitude or duration serve the extreme sections, and the ratio the amplitudes or durations of the pulses supplied to the adjacent areas are determined from the condition A ₁ : A ₂ = X ₁ : X ₂ or T ₁ : T ₂ = X ₁ : X ₂ , where A ₁ , A ₂ are the amplitudes of the pulses fed to neighboring areas

T ₁ , T ₂ - the duration of the pulses applied to adjacent areas

X ₁ , X ₂ - the distance from the longitudinal axis of the electrode to the longitudinal axes of symmetry of the sections, and pulses of the same amplitude or duration as those adjacent to it are pulsed into the section where the axis of symmetry coincides with the axis of symmetry of the electrode. As a result of the redistribution of heat input into the weld pool, the depth of penetration is stabilized across the width of the weld pool and the likelihood of slagging along the fusion line of the base metal with the weld metal and in the overlap zone of adjacent rollers is reduced. 2 Il.

Description

The invention relates to welding and surfacing, in particular to surfacing with strip electrodes, and can be used in the application of coatings with special properties on the working surfaces of products in various fields of engineering, for example, in anticorrosive surfacing of internal surfaces of atomic energy equipment.

The purpose of the invention is to improve the quality of the weld metal by aligning the heat input across the width of the weld pool.

FIG. 1 shows a diagram of the implementation of the proposed method for a tape electrode; in fig. 2 - the same, for a tape electrode of greater width.

To align the heat input across the width of the weld pool, heat input into the weld pool is regulated by synchronously applying welding voltage pulses to the electrode.

ABOUT

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but different amplitudes, or pulses of equal amplitude, but different duration. The supply of these pulses is carried out in such a way as to increase the heat input to the weld pool in its areas with the largest heat sink to reduce heat input in the areas with the minimum heat sink.

The energy of the pulses is determined by the product of amplitude and their duration; therefore, a change in one of these characteristics of the pulses allows the input of energy to change, and in proportion to it, the heat input to the weld pool. The ratio of the powers of the adjacent pulses must be determined by the nature of the change in heat input over the width of the weld pool. Experimentally for the process of surfacing under a flux with a tape electrode, it has been established that the heat input to the weld pool determines its width by the width of its reverse parabola: Y CC, whose axis coincides with the longitudinal axis of the electrode (Fig. 1 and 2). It was established experimentally that

parabola parameter K - and its equation

b 9

has the form Y -jX. Based on this, the ratio of the powers of the pulses should be proportional to the ordinates

b 9 points of the parabola Y X lying on the intersection of the parabola with the axis of symmetry of the sections to which the pulses are fed, turned upside down by 180 ° relative to the parabola

b 7

Y - X. This ratio is determined from

of equality

AI: A2 Y (Xi): Y (X2) or Ti: Ta Y {Xi): Y (X2). where AI and A2 are the amplitudes of the pulses supplied to the adjacent areas:

TI and T2 are the pulses delivered to adjacent areas,

V (X) is the parabola equation;

Xt and X2 are the distances from the longitudinal axis of the electrode to the longitudinal axes of symmetry of the sections;

B is the width of the electrode.

In this case, pulses of greater amplitude or duration are applied to the extreme areas of the electrode. The amplitude or duration of the pulse supplied to the central section, in which the longitudinal axis of symmetry coincides with the longitudinal axis of the electrode, is equal to the amplitude or duration of the pulses supplied to the areas nearest to the MMM.

Tokopodvod these pulses to the plane of the ribbon electrode is carried out using isolated from each

other current-carrying jaws from separate terminals of the source of welding voltage. It has been established by practice that the best results can be achieved provided that

the width of the sections of the ribbon electrode, which are fed to the pulses, is (0.15 - 0.2) b, where b is the width of the ribbon; If this value is greater than 0.2 electrode widths, then the heat input in the weld pool does not effectively level off; if it is less than 0.15 electrode width, it becomes technically difficult to ensure reliable implementation of the method due to the dramatic complexity of the structures.

welding head and source of welding voltage.

The method is carried out as follows.

Ribbon electrodes with a thickness of 0.5–0.7 and a width of 40–100 mm are usually used for submerged arc welding. The amplitude of the pulses supplied to the npi electrode by overlaying (submerged-arc welding) is varied in the range of 10–100 V, and the pulse duration in the range is 10 s. The tape electrode is divided into sections of width (0.15-0.2) of its width, and welding pulses of various amplitudes or durations are applied to these areas using current-jaws.

Example 1. The welding of plates of steel 3 under flux of the OF-10 grade with a ribbon electrode 50 x 0.5 mm in size made of steel C8-07X25N13 was made. Width

Electrode areas to which welding current pulses were applied with the help of current-carrying jaws were chosen to be 0.2 50 10 mm. With such a width of these areas, taking into account the design gaps

between the current-carrying jaws, four jaws are needed. Thus, the longitudinal axes of symmetry of the electrode areas are located, as shown in FIG. 1 at a distance of 5 and 15 mm from the longitudinal axis

electrode. Simultaneously, to these areas of the electrode, through the current-carrying jaws, pulses of welding voltage of equal duration but different amplitude were applied. The ratio of the amplitudes of the pulses supplied

adjacent areas, determined from conditions AI: A2 Y (Xi): Y (X2),

where Y (X) I X 2 X2 12,5,

and Xi 5, Xa 15 mm; Y (Xi) 312.5, Y (X2) 2912.5,

Therefore: AI: A2 1; 9.

A minimum amplitude was taken: a pulse of a welding voltage of 10 V. 8 In this case, pulses with an amplitude of 90 V were applied to the extreme sections of the current lead, and

the pulse duration was assumed to be 10 s,

As a result of surfacing using the proposed method, a high-quality weld bead was produced without undercuts, slag inclusions and non-fusions, with a constant penetration depth across its entire width.

Example 2. The welding of plates of steel 3 under flux of the brand FTs-18 with a ribbon electrode 100 x X 0.7 mm in size made of steel Sv-08Kh19N10G2B was made. We chose the width of the electrode sections to which the welding voltage pulses through the current-carrying jaws equal to 0.15 100 15 mm. With such a width of these sections, taking into account the gaps between the current-jaws, seven jaws are necessary. The longitudinal axes of symmetry of the electrode areas are located, as shown in FIG. 2, at a distance of 15, 30 and 35 mm from the longitudinal axis of the electrode.

Pulses of equal amplitude, equal to 40 V, but of different duration, were applied to the electrode areas synchronously through the current-carrying jaws. The ratio of the duration of the pulses delivered to the neighboring areas was determined from the condition Ti: T2: Tz Y (Xi): Y (X2): Y (Xs),

where y (x)

B

 V2 100. in 2 g, su2.

4 4

Xi 15, X2 30 and. Hz 35mm;

Y (Xi) 5625: Y (X2) 22500; Y (X3) - 30625.

Therefore, Ti: T2; Tz 1: 4: 5,4. A minimum welding voltage pulse duration of 10 s was taken. The duration of the pulses in the extreme areas of the electrode was 5.4–10 s, and the next in the order of their location was 4–10 and 10 s. The duration of mmpulse. supplied to the central part of the electrode (with the coordinate X 0), was taken to be equal to the pulse duration in the adjacent portion, t, e. 10 s.

As a result of surfacing using the proposed method, a bead of good quality welded metal without defects was obtained, with a constant penetration depth across the seam width.

Thus, improving the quality of the weld metal in the proposed

The method is achieved by aligning the heat input across the width of the weld pool. This effect is ensured by redistributing the input of heat into the weld pool by regulated input of energy into the weld pool ps its width.

Claims (1)

The redistribution of heat input into the weld pool changes the conditions of wettability of the base metal with the melted metal and contributes to the improvement of the formation conditions of the rollers. In addition, this redistribution contributes to the stabilization of the depth of penetration across the width of the weld pool, which reduces the likelihood of slagging along the fusion line of the base metal with the weld metal and in the overlap zone of adjacent rollers. The invention The method of arc treatment with a melting electrode, in which pulses of welding voltage of various duration and amplitude are applied to the electrode, characterized in that. in order to improve the quality of the deposited metal by aligning the heat input across the width of the weld pool, a ribbon electrode is used, which is divided into sections 0.15-0.2 wide of its width, and pulses of welding voltage of equal duration but different amplitude are applied simultaneously to them equal amplitude, but of different duration, while the extreme parts of the electrode are supplied with pulses of large amplitude or duration, and the ratio of the amplitudes or durations of the pulses applied to the sections is determined from the condition and AI: A2 Xi: X2 or Ti: T2 Xi: X2, where AI and A2 are the amplitudes of the pulses delivered to the neighboring areas: Xi and X2 are the distances from the longitudinal axis of the electrode to the longitudinal axes of symmetry of the sections: TI and T2 - the duration of the pulses applied to neighboring areas, and the area with the axis of symmetry coinciding with the axis of symmetry of the electrode, serves pulses of the same amplitude or duration as the neighboring areas. f 2 I ft Fig, 1 X, MM J one 3 56 FIG. 2 15 thirty five K, MM