DE8300505U1 - Torch device for narrow gap welding - Google Patents

Description

Erwin-Helmut Günther "&Iacgr;&ogr;. January 1983

Falkenweg 16 5276 Viehl 2

"JSHG/NG

Torch device for narrow gap welding

The invention relates to a burner device for narrow-gap welding (also called narrow-gap welding or steep-flank seam welding), according to the preamble of claim 1

Description

In the last 10 - 15 years, narrow-gap welding has been introduced using various methods for joining thick-walled cross-sections. Significant savings are possible due to savings in filler metal, welding time and energy as a result of smaller seam cross-sections.

Technical advantages include low heat input, consequently good technological quality values in the weld metal and in the heat-affected zone as well as low shrinkage.

Both submerged arc welding and inert gas welding processes have been developed worldwide.

Disadvantages of the UP procedure:

- Powder application and slag removal in the narrow joint.

- The result cannot be checked directly visually ^ which makes complex control and monitoring devices necessary»

- Only one track can be used in one layer, whereby each track (left/right or three-layer technology) must be re-adjusted.

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Disadvantage of the protective gas process:

-Problems caused by lack of fusion, pores and spatter - Both processes with arc oscillation and with double arc are very susceptible to changes in the wire feed and the distance between the arc and the plank (burning up of the arc), which, due to the relatively small melt pools, have a strong influence on penetration and seam geometry.

All processes using arc oscillation also have the disadvantage that the solidification zone (dendrite impact) is located in the middle of the weld, which certainly increases the risk of biting with the large cross-sections.

The narrow-gap, UP and inert gas processes presented so far have the following disadvantages in common:

a) High requirements for the preparation of the weld flanks with regard to surfaces and tolerances of the gap

b) Very complex, expensive equipment and control systems required to ensure precise wire feeding at the bottom of the joint

c) Restriction of economic efficiency due to relatively low welding performance (duty time and deposition rate)

In order to meet the practical requirements for narrow gap welding according to points 1 - 6, the torch device described below was developed for gas shielded welding, which works according to the double arc system in tandem arrangement with 2 power sources.

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- 3 Example of echematiech:

in drawing 1/1 Pig. 1 : burner device lengthways in drawing 1/2 Pig. 2 : burner device crossways and photos 1-3

The presented burner device enables:

1) Weld flank preparation with normal qualified acetylene-oxygen cutting technique

2) Possible tolerances of the selected gap/joint width: approx. ± 1.5 mm

3) Base width of the gap/joint opening can be selected depending on wall thickness and other circumstances, approximately between 1o - 2o mm

4) Two slag burners (right/left) in one pass without slag to ensure economic efficiency in conjunction with reliable penetration into the weld angles/flanks and shifting the resolidification zone within the layer from the center of the weld.

5) High melting performance and duty cycle

6) Large scope for welding speed for the best possible adaptation in terms of optimal heat input and weld geometry

Burners (1) and (2) are isolated from each other (3)» suspended from the upper attachment point with a joint mechanism (4).

The two burners are spread in the gap in the right/left position by spring force, whereby non-current-conducting sliding nozzle elements (half shells) (5) are used to guide the flanks at the bottom of the gap.

10 January 1983

These are used to guide and automatically maintain the rotation distance to the seam flank, even if there are changes in the seam width, and at the same time to guide the gas.

To adapt to different requirements, the sliding nozzle elements are interchangeable and can be used on the guide side in different thicknesses (6).

The spring/joint mechanism (7) for spreading the burners can be locked in the zero position (negative if necessary) for the introduction into the seam joint, as well as in the mex position for the remaining filling in the upper area when there is no longer any lateral guidance.

The torch elements are water-cooled. The distance between the first and second wire is variable.

By attaching the power, water, gas and suspension supplies on one side, the device can also be used for narrow-gap welding of T-connections«(8) The torch device can be used for welding positions w and q.

The requirements of points 1-6 are particularly met when metal cored wires are used in conjunction with this device, which are welded with two direct current sources at the negative pole. The slag content of 3 - 5 % of these cored wires is so small that it does not need to be removed; individual small islands of slag fall off on their own when they cool down. Due to the flexibility of these cored wires, the 1.6 mm diameter can be used without any problems. In conjunction with mixed gas Ar + 5 % CO, melting rates per wire of approx. 6 - 9 kg/h can be achieved with this, with a low spatter content, optimal seam formation and penetration conditions and a wide range of welding speeds (approx. 50 - 100 cm/min.).

10 January 1983 "EHG/NG

When using solid wire electrodes, the optimal diameter should be 1.2 mm. Modern pulse current sources should be used to ensure the lowest possible spatter formation.

Electronic controls should be used to control the wire feed, which keep the parameters current and voltage constant when the free wire length (stickout) changes, so that tolerances in the gap width are compensated for automatically by adjusting the melting power.

Claims (1)

Erwin-Helmut Günther 1o. January 1983 Palkenweg 16 .: .: .··. .: ...EBG/NG 5276 Wiehl 2 .·. .j. * &iacgr;,.&idigr; ,f. * :":. \* nspruch 1. Torch device for the gap welding (also called narrow gap or steep flank welding) according to the protective gas welding process using double arc technology in tandem arrangement with two power sources. Characterized in that two burner elements are suspended in an insulated manner (3) from one another by means of a spring/joint mechanism (4), adjustable and lockable (7), whereby in conjunction with non-current-carrying sliding nozzle elements (5) (6) at the bottom of the seam gap, self-control of the wire electrode distances to the seam flanks is achieved, even if changes in the width of the gap occur.