CN103056537A

CN103056537A - Method for welding large casting ball valves

Info

Publication number: CN103056537A
Application number: CN2012105738963A
Authority: CN
Inventors: 王志平; 肖德政; 段世新; 白金生
Original assignee: CITIC Heavy Industries Co Ltd
Current assignee: CITIC Heavy Industries Co Ltd
Priority date: 2012-12-26
Filing date: 2012-12-26
Publication date: 2013-04-24
Anticipated expiration: 2032-12-26
Also published as: CN103056537B

Abstract

The invention discloses a method for welding large casting ball valves and relates to the welding technical field. Through the application of a two-step rotation method, the production cost and the potential safety hazard caused by scaffold setting and adopting of anti-dumping measures are reduced, and the welding quality is improved. Simultaneously, valve rotation and valve body welding are convenient and simple to operate, the welding deformation control is good, the process economy is high, and the method is suitable for large-scale promotion and application.

Description

A kind of welding method of heavy castings ball valve

[technical field]

The present invention relates to welding field, be specifically related to a kind of welding method of heavy castings ball valve.

[background technology]

Known, the overall size of heavy castings ball valve is large, tonnage is heavy, needs welding minute half a broadwise girth joint after its two halves valve body assembling, and traditional welding method to be assembly welding with the two halves valve body adopt vertical assembling, then directly weld at vertical state, its welding position is horizontal position welding, guarantees comparatively difficulty of welding quality when adopting the method welding, simultaneously comparatively inconvenience of polishing after the welding, and need to scaffold erecting and take the overturning-preventing measure, and then greatly increased production cost; Further because under vertical state during the weld seam of welding valve body inboard, because valve rotates difficulty, this moment just need to be with overhead traveling crane with the valve certain altitude of slinging, then rotate valve by artificial or other modes, the method operability is poor, most importantly welding slag is fallen into gap between valve spindle nose and the valve body axis hole easily when adopting vertical welding, clear up extremely inconvenient, because the heavy castings valve body divides half broadwise girth joint thickness large, the weld metal loading is large, the deadweight of valve body can strengthen the contraction of weld seam transverse weld during vertical welding, the cross-direction shrinkage of several passage weld seams particularly, the distortion that this moment, the weld seam cross-direction shrinkage caused very easily makes valve spindle nose and valve body axle axle place push.

[summary of the invention]

For overcoming the deficiency that exists in the background technology, the invention provides a kind of welding method of heavy castings ball valve, the present invention is by the application of two step rotary process, production cost and potential safety hazard because scaffolding erecting, take the overturning-preventing measure to cause have been reduced, it is high to have welded quality, simultaneously valve rotation and valve body welding operation are convenient and simple, and welding deformation control is good, and process economy is high.

For realizing aforesaid goal of the invention, the present invention adopts technical scheme as described below:

A kind of welding method of heavy castings ball valve, described welding method specifically comprises the steps:

The first step is at first estimated weld seam cross-direction shrinkage amount according to thickness and the groove size of ball valve body 1, then by the technique backing plate 4 of estimating weld shrinkage processing respective thickness;

Second step keeps at a certain distance away technique backing plate 4 on the uniform root face that spots weld weld groove, and wherein technique backing plate 4 stretches out laterally and can not exceed root face edge 10mm, technique backing plate 4 can be disposed when guaranteeing inboard back chipping;

The 3rd step, two halves valve body 1 is pulled open the gap as the amount of contraction of weld seam welding by technique backing plate 4 when assembling, then carry out vertical assembling, the butt welded seam outside two-layer two halves valve body 1 that makes of bottoming welding is connected firmly under vertical state;

The 4th step, the ball valve accumbency is put, this moment, the welding position of weld seam was downhand welding, ball valve repeatedly stands up, the welding sequence that adopts upper outside weld seam and lower inside weld seam to weld simultaneously, and weld seam is inboard back chipping when the bottom, wherein when inboard welding and back chipping, after length direction welds half, utilize two step rotary process rotation valve 2, weld second half weld seam after rotating 90 °.

The welding method of described heavy castings ball valve, the first step of described two step rotary process is directly to vise valve 2 edges with tongs 5, overhead traveling crane lifting valve 2 also makes 45 ° of its rotations, second step is at the interim hanger 6 of valve 2 welding, hang interim hanger 6 with overhead traveling crane and rotate again 45 °, thereby realize 90 ° of rotations of valve 2 realizations, both sides operate 360 ° of rotations that can realize valve 2 repeatedly.

Adopt aforesaid technical scheme, the present invention has superiority as described below:

The welding method of a kind of heavy castings ball valve of the present invention, the present invention is by the application of two step rotary process, production cost and potential safety hazard because scaffolding erecting, take the overturning-preventing measure to cause have been reduced, it is high to have welded quality, simultaneously valve rotation and valve body welding operation are convenient and simple, welding deformation control is good, and process economy is high, is fit to large-scale promotion and application.

[description of drawings]

Fig. 1 is assembling schematic diagram of the present invention;

Fig. 2 is welded condition schematic diagram of the present invention;

Fig. 3 is that the present invention utilizes the tongs valve body schematic diagram of slinging;

Fig. 4 is interim hanger welding schematic diagram of the present invention;

In the drawings: 1, valve body; 2, valve; 3, valve body hanger; 4, technique backing plate; 5, tongs; 6, interim hanger.

[specific embodiment]

Can explain in more detail the present invention by the following examples, the present invention is not limited to the following examples;

The welding method of 1～4 described a kind of heavy castings ball valve by reference to the accompanying drawings, described welding method specifically comprises the steps:

Second step, on the uniform root face that spots weld weld groove of technique backing plate 4 intervals 5～50mm, wherein technique backing plate 4 stretches out laterally and can not exceed root face edge 10mm, technique backing plate 4 can be disposed when guaranteeing inboard back chipping;

The 4th step, the ball valve accumbency is put, this moment, the welding position of weld seam was downhand welding, ball valve repeatedly stands up, the welding sequence that adopts upper outside weld seam and lower inside weld seam to weld simultaneously, weld seam is inboard back chipping when the bottom, wherein when inboard welding and back chipping, after length direction welds half, utilize two steps rotary process rotation valve 2, second half weld seam of welding after rotating 90 °, the first step of described two step rotary process is directly to vise valve 2 edges with tongs 5, overhead traveling crane lifting valve 2 also makes 45 ° of its rotations, second step is at the interim hanger 6 of valve 2 welding, hang interim hanger 6 with overhead traveling crane and rotate 45 ° again, thereby realize 90 ° of rotations of valve 2 realizations, both sides operate 360 ° of rotations that can realize valve 2 repeatedly.

Further the present invention will be described below in conjunction with specific embodiment:

1, utilize technique backing plate 4 to stay the vertical assembling in gap:

Thickness and groove size according to ball valve body 1 are estimated weld seam cross-direction shrinkage amount, by the technique backing plate 4 of estimating weld shrinkage preparation respective thickness, for example be of a size of the little steel plate of 6mm * 30mm * 30mm, on the uniform root face that spots weld weld groove of technique backing plate 4 interval 20mm, technique backing plate 4 stretches out laterally and can not exceed root face edge 10mm, technique backing plate 4 can be disposed when guaranteeing inboard back chipping, the preset clearance of two weld seams was consistent when technique backing plate 4 can not only guarantee valve body 1 assembling, and can reduce the transverse weld amount of contraction of weld seam;

Ball valve from valve body 1 outside, is used the gas shielded arc welding symmetrical welding under vertical state, two-layer to two weld seam bottoming welding simultaneously, and two halves valve body 1 is connected firmly.

2, ball valve welds under the accumbency state:

Directly utilize four valve body hangers, 3 conducts on the valve body 1 to support, the ball valve accumbency that assembles is placed in ground, ball valve is highly stable under this state, need not scaffold erecting and take measures to prevent that ball valve from toppling over, and the welding position of inside and outside side weld all is downhand welding, be conducive to improve welding quality, minimizing is reprocessed, ball valve is when the accumbency state simultaneously, and the weld grinding position is good, and labour intensity is low;

3, the welding sequence of weld seam:

The welding sequence that adopts upper outside weld seam and lower inside weld seam to weld simultaneously, weld seam is inboard back chipping when the bottom, welding process is repeatedly stood up owing to ball valve, wherein when the inboard welding of weld seam and back chipping, after length direction welds half, utilize two step rotary process rotation valve 2, weld second half weld seam after rotating 90 °;

4, rotation valve:

Ball valve is in the accumbency state, two step rotary process are adopted in valve 2 rotations, the first step is to vise the edge of valve 2 with tongs 5, the overhead traveling crane lifting can be with valve 2 half-twists, second step is at the interim hanger 6 of valve 2 welding, hang again half-twist of interim hanger 6 with overhead traveling crane, thereby realize that operation realizes valve 2 is realized 360 ° of rotations repeatedly with valve 2 Rotate 180s °.

Part not in the detailed description of the invention is prior art.

The embodiment that selects in this article in order to disclose purpose of the present invention currently thinks to suit, and still, will be appreciated that the present invention is intended to comprise that all belong to all changes and the improvement of the embodiment in this design and the invention scope.

Claims

1. the welding method of a heavy castings ball valve, it is characterized in that: described welding method specifically comprises the steps:

The first step is at first estimated weld seam cross-direction shrinkage amount according to thickness and the groove size of ball valve body (1), then by the technique backing plate (4) of estimating weld shrinkage processing respective thickness;

Second step keeps at a certain distance away technique backing plate (4) on the uniform root face that spots weld weld groove, and wherein technique backing plate (4) stretches out laterally and can not exceed root face edge 10mm, technique backing plate (4) can be disposed when guaranteeing inboard back chipping;

The 3rd step, two halves valve body (1) is pulled open the gap as the amount of contraction of weld seam welding by technique backing plate (4) when assembling, then carry out vertical assembling, the butt welded seam outside two-layer two halves valve body (1) that makes of bottoming welding is connected firmly under vertical state;

The 4th step, the ball valve accumbency is put, this moment, the welding position of weld seam was downhand welding, ball valve repeatedly stands up, the welding sequence that adopts upper outside weld seam and lower inside weld seam to weld simultaneously, and weld seam is inboard back chipping when the bottom, wherein when inboard welding and back chipping, after length direction welds half, utilize two step rotary process rotation valve (2), weld second half weld seam after rotating 90 °.

2. the welding method of heavy castings ball valve according to claim 1, it is characterized in that: the first step of described two step rotary process is directly to use tongs (5) to vise valve (2) edge, overhead traveling crane lifting valve (2) also makes 45 ° of its rotations, second step is at valve (2) welding interim hanger (6), hang interim hanger (6) with overhead traveling crane and rotate again 45 °, thereby realize 90 ° of rotations of valve (2) realization, both sides operate 360 ° of rotations that can realize valve (2) repeatedly.