SU1466890A1 - Method of butt resistance flash welding - Google Patents

Abstract

The invention relates to flash butt welding, and can be used to join various parts. The purpose of the invention is to improve the quality of the welded joint while improving the mustache, the load of the supply network. To do this, determine the maximum gap that is formed between the welded ends of the parts during the fusion process. The current is deposited until it reaches a value equal to that of the gap. The method allows to reduce the overheating of the welded materials in the contact zone at the time of current deposition due to accurate determination of the time of this stage of precipitation and, thereby, to increase the quality stability and strength of welded joints. Rational choice of precipitation can significantly improve the load conditions e, |

Description

one

The invention relates to flash butt welding and can be used for welding various parts.

The purpose of the invention is to improve the quality of the welded joint while improving the load conditions of the supply network by choosing the optimal amount of current draft.

Before the melting or during it, the value of the maximal Lumax gap, which is formed between the welded ends of the parts during the melting, is determined, for example, the numerical value can be calculated using the empirical formula (for thicknesses from 5 to 20 mm)

D, max t / a (0.022, 2),

where t / 2M is the no-load voltage of the secondary winding of the welding transformer, V;

5 - thickness of welded products, mm.

Then, the melting and slump, part of which is carried out under the current meter, is carried out.

Sediment under current is carried out until it reaches a value equal to the maximum gap during fusion.

Example. Before welding pipes with a diameter of 1420 mm, the K 700-I mask determines the maximum spark gap AjMaKc at, 5 V, mm (pipe wall thickness)

#

) - l.

(

four

AZ "AX 7.5 (0.022. 15 + 0.2) 4.2 mm.

When welding on the machine K. 700-1, the precipitation rate is 40 mm / s.

Knowing the value of the precipitation rate, determine the time of precipitation under current:

,,., () 5 s.

When welding with a draft under current for a time longer than 0.105 s, there is a decrease in the quality of welded joints due to overheating of the metal.

In the case when the draft is conducted under a current for a time less than 0.105 s, oxide films are formed on the areas of the surfaces to be joined before it is closed.

a blood gap, which leads to the appearance of unacceptable defects in the joint zone, reducing the quality of the welded joint.

The method allows to reduce the overheating of the welded materials in the contact zone at the time of current deposition due to accurate determination of the time of this precipitation stage and, thereby, to improve the quality of the welded joint.

Rational choice of the duration of the precipitation allows to significantly improve the load conditions of the power grid.

Claims (1)

Invention Formula The flash butt welding method, in which the value of the maximum gap formed between the ends to be welded during the reflow process is determined, and then voltage is applied to the parts to be welded, and the voltage is melted, slumped and switched off. In order to improve the quality of the connection while simultaneously improving the load conditions of the power grid, the voltage is turned off when the draft reaches a value equal to the maximum gap.