CN100464920C - Obstacle-free butt welding method for straight pipe with small diameter - Google Patents

Abstract

The present invention relates to an unobstructed small-caliber straight pipe butting welding method which is characterized in the rolling type continuous filament-feeding welding method, meaning regarding the full crater as a clock wherein the bottom is 6 o'clock and the left and right side is separately 3 o'clock and 9 o'clock and the welding torch always stays at 2 o'clock, showing 12 o'clock welding state, increasing the welding current, using continuous filament feeding welding method after a fuse bath happens, which makes the fused bath metal fully filter the welding line base and the welding line fully fused with the mother materials at the two ends at the effect of gravity and arc blowing force. The present invention has the virtue of 'rolling type' butting joint, which greatly reduces subsidiary workload, accelerates production circulation, increases crater butting joints, effectively controls and prevents the production of inside recess and inadequate penetration flaw and increases the percent of pass from 93% to 97-98%, which greatly accelerates the production circle.

Description

Accessible straight pipe with small diameter butt joint welding method

Technical field

The present invention relates to a kind of accessible straight pipe with small diameter butt joint welding method, can be used for the welding of station boiler heating surface pipe, belong to the small-bore pipe welding technology field.

Background technology

In the manufacturing process of big capacity steam boiler, all diameters are called small-bore pipe at the pipe of Φ 22mm-72mm, wall thickness δ 〉=4mm, small-bore pipe butt joint welding is an important processing method of boiler heating surface pipe, the quality of its welding quality has a direct impact manufacturing cost and manufacturing schedule, traditional welding method, be to adopt the GTAW back cover, the manual electric arc welding capping, this welding method is easy to generate internal concave at root and incomplete penetration defect most when root feels secure.

Summary of the invention

The objective of the invention is to invent a kind of accessible straight pipe with small diameter butt joint welding method that when root feels secure, does not produce internal concave at root and lack of penetration phenomenon.

For realizing above purpose, technical scheme of the present invention provides a kind of accessible straight pipe with small diameter butt joint welding method, it is characterized in that, adopt roller to add wire bond continuously and connect method, whole weld bond looked to do below the clock and watch promptly be 6 points, about be respectively 9 and 3 points, welding torch rests on 2 positions all the time, be state to 12 means of spot welds, the increase welding current adopts the method that adds welding wire continuously after treating that the molten bath occurs, and makes molten pool metal under the effect of gravity and blow force of arc, can permeate the root of weld fully, fully fuse with the two ends mother metal.

When carrying out the all-position welding of argon arc welding back cover, the misalignment of the time that the interpolation of the power of blowing of the limit matter of speed of welding, welded gaps, bevel angle, obstacle, the size of tube pitch, electric arc, the temperature in molten bath, welding wire, welding torch stop, the thickness of tube wall, counterpart whether, angle, the arc blow of size, welding torch and the weld seam of root face, it all is the reason that produces indent and incomplete penetration defect generation, the present invention is directed to different reasons, propose solution, controlled and prevented the generation of indent and incomplete penetration defect effectively.

Advantage of the present invention is:

1. adopt " roller " butt joint, reduced the back work amount greatly, accelerated the cycle of production flow, weld bond butt joint amount obviously increases;

2. the present invention controls and has prevented the generation of indent and incomplete penetration defect effectively;

3. the accessible straight pipe with small diameter of the present invention butt joint weld bond first-time qualification rate rises to 97%～98% from 93%, and the weld bond first-time qualification rate obviously rises, and has accelerated the production cycle greatly.

Description of drawings

Fig. 1 is accessible straight pipe with small diameter horizontal level welding direction schematic diagram.

The specific embodiment

The invention will be further described below in conjunction with drawings and Examples.

Embodiment 1

As shown in Figure 1, be accessible straight pipe with small diameter horizontal level welding direction schematic diagram, adopt roller to add wire bond continuously and connect method, whole weld bond 1 looked to do below the clock and watch promptly be 6 points, about be respectively 9 and 3 points, welding torch 4 rests on 2 positions all the time, be state to 12 means of spot welds, after the increase welding current treats that the molten bath occurs, adopt the method that adds welding wire continuously, make molten pool metal under the effect of gravity and blow force of arc, can permeate the root of weld fully, fully fuse with the two ends mother metal.

Claims (1)

1. an accessible straight pipe with small diameter docks welding method, it is characterized in that, adopt roller to add wire bond continuously and connect method, whole weld bond (1) looked to do below the clock and watch promptly be 6 points, about be respectively 9 and 3 points, welding torch (4) rests on 2 positions all the time, be state to 12 means of spot welds, after the increase welding current treats that the molten bath occurs, adopt the method that adds welding wire continuously, make molten pool metal under the effect of gravity and blow force of arc, can permeate the root of weld fully, fully fuse with the two ends mother metal.

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