CN1385272A

CN1385272A - Arc stricking method for metal gas arc welding

Info

Publication number: CN1385272A
Application number: CN 02112263
Authority: CN
Inventors: 华学明; 吴毅雄; 张勇; 蔡艳; 付延安; 石忠贤; 于乾波
Original assignee: Shanghai Jiaotong University
Current assignee: Shanghai Jiaotong University
Priority date: 2002-06-27
Filing date: 2002-06-27
Publication date: 2002-12-18
Anticipated expiration: 2022-06-27
Also published as: CN1186161C

Abstract

The method for striking the arc for metal gas arc welding belongs the field of welding technology, and includes the following steps: firstly, slow wire-feeding stage, its slow wire-feeding speed is 1/2-3/4 of normal set wire-feeding speed, when the end portion of welding wire is contacted with workpiece, stopping feeding wire; wire-feeding stopping stage; inertia of wire-feeding motor can continuously feed wire in a microsmall distance, producing reliable short circuit, when the welding power supply judges the arc is formed, instantly switching on wire-feeding drive circuit, feeding wire downwards in speed less than normal wire-feeding speed, after the arc is strived, making slow wire-feedins stage again, the time of said stage is controlled in 1-20 sm; after the arc is stabilized, the arc-striking operation is completed, starting normal wire-feeding speed.

Description

The striking method of molten electrode protected by gas arc welding

Technical field: what the present invention relates to is a kind of striking method of arc welding, and particularly a kind of striking method of molten electrode protected by gas arc welding belongs to welding technology field.

Background technology: the molten electrode protected by gas arc welding is after the work of welding starting switch, and the time of leading to a segment protect gas earlier in advance, welding wire is down sent to then, behind the contact workpiece, relies on short circuit current that welding wire and workpiece contact portion instant melting are produced electric arc.Find by literature search; Han Debin is in " Tohoku Electric Power technology "; write articles " arcing initiation success rate that improves welding machine " on 1994 (8); the molten electrode protected by gas arc welding striking technology that adopts in this article is when the beginning striking; wire feed rate is sent to downwards with slower speed by the circuit that designs, and rises to the wire feed rate that sets again behind the electric arc of waiting to ignite.Molten electrode protected by gas arc welder on the domestic market mostly adopts this kind to be referred to as the striking method of slow wire feed.But this method is to be under the prerequisite that welding wire sends to continuously, rely on the short circuit current filler wire to contact the end with workpiece and realize striking, when electrode extension longer, since welding wire when contacting with workpiece still at wire feed, the effect of wire feeding force makes welding wire extend bending outward, welding wire extends the middle part sectional area outward and diminishes and cause heat to concentrate to cause that welding wire becomes section quick-fried disconnected, simultaneously because the contact resistance of the effect welding wire of wire feeding force and workpiece is less, the heat fused that is unfavorable for the welding wire end, thereby be unfavorable for the striking success, this striking still is difficult to avoid quick-fried disconnected phenomenon and causes the striking failure.

The summary of the invention and the specific embodiment: the present invention is directed to the deficiencies in the prior art and defective; a kind of striking method of molten electrode protected by gas arc welding is provided; the slow wire feed of elder generation that the present invention adopts-stop wire feed-slow again wire feed; change the striking method of the wire feed rate that sets then over to, quick-fried disconnected phenomenon when having solved striking.

Description of drawings: Fig. 1 arc process schematic diagram

The earlier slow wire feed rate of Fig. 2 changes schematic diagram greater than the arc process wire feed rate of slow wire feed again

The earlier slow wire feed rate of Fig. 3 changes schematic diagram less than the arc process wire feed rate of slow wire feed again

The arc process wire feed rate that the slow again wire feed rate of Fig. 4 increases progressively continuously changes schematic diagram

The specific embodiment: as shown in Figure 1, Figure 2, Figure 3 and Figure 4, method of the present invention is specific as follows: behind the operating switch of the molten electrode protected by gas arc welding of closing, supply gas in advance, enter arc process then:

Step 1: earlier slow 1 stage of wire feed, 1/2～3/4 speed of the wire feed rate that the beginning feed rate of welding wire sets with normal welding is sent to downwards, be in earlier slow 1 stage of wire feed, this moment, the source of welding current constantly detected weldingvoltage, welding current signal, according to weldingvoltage, welding current signal judges whether the welding wire end contacts with workpiece, and the source of welding current sends signal and stops earlier slow wire feed 1 when the welding wire end contacts with workpiece;

Step 2: earlier slow 1 stage of wire feed enters after finishing and stops 2 stages of wire feed, this moment, welding wire was because the inertia of wire feeding motor also continues to send to slight distance, it is more reliable that the welding wire end is contacted with workpiece, the reliable short circuit of welding wire and workpiece simultaneously, the end that the rapid filler wire of the short circuit current that welding machine provides contacts with workpiece, because this moment, welding wire stopped to send to, the equilibrium problem of burn-off rate and wire feed rate does not take place, welding wire end moment of having melted produces the gap and forms arc space, when the weldingvoltage of the source of welding current by detecting, after welding current signal judges that electric arc has formed, moment is connected the wire feed drive circuit, welding wire is sent to downwards with the wire feed rate 4 little speed that set than normal welding again, promptly is in slow 3 stages of wire feed again;

Step 3: stop to enter after 2 stage of wire feed, electric arc ignited again slow 3 stages of wire feed, slow again wire feed of this stage is to set for the stable electric arc of just having set up that ignites, this section period is controlled between 1～20ms, for stablizing slow again 3 stages of wire feed that the electric arc that just ignited is set, its slow wire feed pattern can be two kinds, a kind of is permanent slow wire feed, a kind of wire feed that increases progressively continuously, when adopting perseverance wire feed pattern at a slow speed, the wire feed rate in slow 3 stages of wire feed can be faster than the wire feed rate in slow 1 stage of wire feed of elder generation again, also can be slower, when employing increases progressively the wire feed pattern continuously, wire feed rate is to be increased to the wire feed rate 4 that normal welding sets gradually continuously from zero, and striking finishes behind slow 3 stage of wire feed arc stability again;

Step 4: when above-mentioned steps 1, step 2, after the successful striking of step 3, slow again wire feed 3 phase transition are welded 4 stages of wire feed rate that set to normal.

The present invention has substantive distinguishing features and marked improvement; adopt the slow wire feed of elder generation of the present invention-stop wire feed-slow again wire feed; change the striking method of the wire feed rate that sets then over to; through a large amount of tests; the success rate of striking is high; significantly reduce the quick-fried disconnected possibility of welding wire, realized that the molten electrode protected by gas arc welding do not have the soft striking of splashing.

Claims

1, a kind of striking method of molten electrode protected by gas arc welding is characterized in that method is specific as follows: behind the operating switch of the molten electrode protected by gas arc welding of closing, supply gas in advance, enter arc process then:

Step 1: earlier slow wire feed (1) stage, 1/2～3/4 speed of the wire feed rate that the beginning feed rate of welding wire sets with normal welding is sent to downwards, this moment, the source of welding current constantly detected weldingvoltage, welding current signal, according to weldingvoltage, welding current signal judges whether the welding wire end contacts with workpiece, and the source of welding current sends signal and stops earlier slow wire feed (1) when the welding wire end contacts with workpiece;

Step 2: earlier slow wire feed (1) stage enters after finishing and stops wire feed (2) stage, welding wire is because the inertia of wire feeding motor also continues to send to slight distance, the reliable short circuit of welding wire and workpiece simultaneously, the end that the rapid filler wire of the short circuit current that welding machine provides contacts with workpiece, this moment, welding wire stopped to send to, welding wire end moment of having melted produces the gap, form arc space, when the weldingvoltage of the source of welding current by detecting, after welding current signal judges that electric arc has formed, moment is connected the wire feed drive circuit, and welding wire is sent to downwards with the little speed of wire feed rate (4) that sets than normal welding again, promptly is in slow wire feed (3) stage again;

Step 3: stop to enter after wire feed (2) stage electric arc ignites again slow wire feed (3) stage, this section period is controlled between 1～20ms, its slow wire feed pattern can be divided two kinds, a kind of is permanent slow wire feed, a kind of wire feed that increases progressively continuously, when adopting perseverance wire feed pattern at a slow speed, the wire feed rate in slow wire feed (3) stage can be faster than the wire feed rate in elder generation's slow wire feed (1) stage again, also can be slower, when employing increases progressively the wire feed pattern continuously, wire feed rate is to be increased to the wire feed rate (4) that normal welding sets gradually continuously from zero, and striking finishes behind slow wire feed (3) stage arc stability again;

Step 4: when above-mentioned steps 1, step 2, after the successful striking of step 3, slow again wire feed (3) phase transition is welded wire feed rate (4) stage that sets to normal.