阅读说明：本技术 对开三通组对焊接方法 (Split tee fitting assembly welding method ) 是由 滕平强 吴子山 于 2020-08-11 设计创作，主要内容包括：本发明涉及对开三通焊接技术领域,具体公开了一种对开三通组对焊接方法,包括以下步骤：将上护板与下护板套装在母管的外侧,形成两道直焊缝和两道环焊缝；两道环焊缝与每道直焊缝的相交分别形成A交叉点和B交叉点；对直焊缝和环焊缝处理；对两道直焊缝均分为多段并同时焊接；在两道直焊缝焊接完毕后,对两道环焊缝焊接；将每道环焊缝均分为两段,包括含有A交叉点的A段环焊缝和含有B交叉点的B段环焊缝,其中B段环焊缝以顺时针方向焊接,A段环焊缝以逆时针方向焊接,A段环焊缝和B段环焊缝同时焊接。本发明利用直焊缝和环焊缝不同的焊接工序,避免造成应力集中与氢裂事故的发生；直焊缝的焊接坡口采用单边坡口型式,减少了大量焊接工作量。(The invention relates to the technical field of split tee welding, and particularly discloses a split tee assembly welding method, which comprises the following steps: sleeving an upper protection plate and a lower protection plate on the outer side of the main pipe to form two straight welding seams and two circumferential welding seams; the intersection of the two circular welding seams and each straight welding seam respectively forms an A intersection point and a B intersection point; straight welding seams and girth welding seams are processed; dividing two straight welding seams into multiple sections and welding simultaneously; after the two straight welding seams are welded, welding the two circular welding seams; and each girth weld is divided into two sections, wherein each section of girth weld comprises an A section of girth weld with an A intersection and a B section of girth weld with a B intersection, the B section of girth weld is welded in a clockwise direction, the A section of girth weld is welded in a counterclockwise direction, and the A section of girth weld and the B section of girth weld are welded simultaneously. The invention utilizes different welding procedures of the straight welding seam and the circumferential welding seam to avoid stress concentration and hydrogen cracking accidents; the welding groove of the straight welding seam adopts a single-side groove type, so that a large amount of welding workload is reduced.)

1. The split tee assembly welding method is characterized in that: the method specifically comprises the following steps:

sleeving an upper protection plate (1) and a lower protection plate (2) on the outer side of a main pipe (4) to form two straight welding seams (10) and two circumferential welding seams (20); wherein, the intersection of the two girth welds (20) and each straight weld (10) respectively forms an A intersection point and a B intersection point;

processing a straight welding seam (10) and a circumferential welding seam (20) formed by the upper protection plate (1) and the lower protection plate (2);

two straight welding seams (10) formed by the upper protection plate (1) and the lower protection plate (2) are divided into a plurality of sections and are welded simultaneously;

after the two straight welding seams (10) are welded, welding the two circular welding seams (20); each girth weld (20) is divided into two sections, including an A-section girth weld containing an A intersection and a B-section girth weld containing a B intersection, and the A-section girth weld and the B-section girth weld are divided into a plurality of small sections, wherein the B-section girth weld is welded in a clockwise direction, the A-section girth weld is welded in a counterclockwise direction, and the A-section girth weld and the B-section girth weld are welded simultaneously.

2. The split tee set butt welding method according to claim 1, characterized in that: the two straight welding seams (10) are equally divided into multiple sections and are welded simultaneously, and the method specifically comprises the following steps: dividing each straight welding line (10) into three sections, and respectively welding by three welders; during welding, two straight welding seams (10) are welded simultaneously; the welding directions of the middle sections of the two straight welding seams (10) are opposite, and the welding directions of the other two sections in each straight welding seam (10) are opposite and are welded to one side far away from the middle sections.

3. The split tee set butt welding method according to claim 1, characterized in that: the straight weld joint (10) is a single-side groove weld joint, the angle of the single-side groove weld joint is a, and the angle a is 40-50 degrees.

4. The split tee set butt welding method according to claim 1, characterized in that: when the straight welding line (10) is welded, argon arc welding is adopted for bottoming, and the cover surface is subjected to electric arc welding.

5. The split tee set butt welding method according to any one of claims 1 to 4, wherein: equally dividing each girth weld (20) into two sections, including an A section girth weld containing an A cross point and a B section girth weld containing a B cross point, and equally dividing the A section girth weld and the B section girth weld into a plurality of small sections, specifically: each circumferential weld (20) is divided into two sections along the vertical direction, and the circumferential weld of the section A and the circumferential weld of the section B are divided into four small sections.

6. The split tee set butt welding method according to claim 5, wherein:

the welding in the clockwise direction specifically means: the ring welding seam of the section B takes the end part of the ring welding seam, which is far away from one side of the split tee flange (3), as a starting point, and the ring welding seam of the section B is sequentially welded in the clockwise direction;

the welding in the counterclockwise direction specifically means: and the A-section girth weld takes the A cross point as a starting point, two welders sequentially weld in the anticlockwise direction, and after the welding is finished, the two welders sequentially weld in the anticlockwise direction by taking the end part of the section of girth weld, which is far away from one side of the split tee flange (3), as a starting point.

7. The split tee set butt welding method according to claim 5, wherein: the circumferential weld (20) adopts a multi-pass surfacing welding mode, and the thickness of each welding layer is 2.0-3.0 mm.

8. The split tee set butt welding method according to claim 1, characterized in that: the straight welding seam (10) and the circumferential welding seam (20) formed by the upper protection plate (1) and the lower protection plate (2) are treated, and the treatment specifically comprises the following steps: and removing oil stains and oxidation layers within 50mm of the edges of the straight welding line (10) and the girth welding line (20).

Technical Field

The invention relates to the technical field of split tee welding, in particular to a split tee assembly welding method.

Background

The traditional split tee welding process method is not suitable for large-caliber split tee welding with the caliber of more than 1420mm, the existing welding process adopts a single-side single-person welding method, and the method is easy to cause stress concentration so as to generate a hydrogen cracking phenomenon. Welding stress is caused by uneven temperature field generated by welding heating, stress concentration is easy to occur to stress in the axial direction of a welding seam under various stresses, stress concentration and hydrogen cracking are easy to occur to the welding seam, and further the tee joint welding work fails, so that the construction progress is slow, and the construction cost is increased; meanwhile, when straight welding seams and circular welding seams are welded in the prior art, the number of welders is small, so that the workload of each welder is large, the welders are extremely easy to fatigue excessively, and the safety factor is greatly reduced due to the fact that the tee joint is welded under pressure in the process of butt-joint welding.

Disclosure of Invention

The invention aims to solve the technical problem of providing a split tee assembly welding method, which can avoid the occurrence of hydrogen crack accidents caused by stress concentration during the assembly welding of large-caliber split tees.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the split tee assembly welding method is characterized in that an upper protection plate and a lower protection plate are sleeved on the outer side of a main pipe to form two straight welding seams and two circular welding seams; wherein, the two girth welds and each straight weld form A cross point and B cross point respectively;

processing a straight welding line and a circumferential welding line formed by the upper protection plate and the lower protection plate;

two straight welding seams formed by the upper guard plate and the lower guard plate are divided into a plurality of sections and are welded simultaneously;

after the two straight welding seams are welded, welding the two circular welding seams; equally dividing each girth weld into two sections, wherein each section comprises an A section girth weld with an A intersection and a B section girth weld with a B intersection, and equally dividing the A section girth weld and the B section girth weld into a plurality of small sections, wherein the B section girth weld is welded in a clockwise direction, the A section girth weld is welded in a counterclockwise direction, and the A section girth weld and the B section girth weld are welded simultaneously.

Further, in order to enable the formed stress to be dispersed when the straight welding seam is welded; the two straight weld joints are equally divided into a plurality of sections and welded simultaneously, and specifically the method comprises the following steps: dividing each straight welding line into three sections, and welding by three welders; during welding, two straight welding seams are welded simultaneously; the welding directions of the middle sections of the two straight welding seams are opposite, and the welding directions of the other two sections in each straight welding seam are opposite and are welded to the side far away from the middle section.

Further, in order to reduce welding workload, the straight weld is a single-side groove weld, the angle of the single-side groove weld is a, and a is 40-50 °.

Further, in order to enhance the welding quality of the straight welding seam, the welding of the straight welding seam meets related requirements, and argon arc welding is adopted for bottoming and electric arc welding for capping when the straight welding seam is welded.

Further, in order to prevent the stress generated during the circumferential weld welding from concentrating; equally dividing each girth weld into two sections, including an A section girth weld containing an A intersection and a B section girth weld containing a B intersection, and equally dividing the A section girth weld and the B section girth weld into a plurality of small sections, specifically: and dividing each circumferential weld into two sections along the vertical direction, and dividing the circumferential weld of the section A and the circumferential weld of the section B into four small sections.

Further, the welding in the clockwise direction specifically means: the B-section girth weld is welded in sequence in the clockwise direction by taking the end part of the side, away from the split tee flange, of the B-section girth weld as a starting point;

the welding in the counterclockwise direction specifically means: and the A-section girth weld takes the A cross point as a starting point, two welders sequentially weld in the anticlockwise direction, and after the welding is finished, the two welders sequentially weld in the anticlockwise direction by taking the end part of the section girth weld, which is far away from one side of the split tee flange, as a starting point.

Furthermore, in order to reduce the occurrence probability of the air holes and slag inclusion problems of the welding line; the circumferential weld adopts a multi-pass surfacing welding mode, and the thickness of each welding layer is 2.0-3.0 mm.

Further, the straight weld seam and the circumferential weld seam formed by the upper protection plate and the lower protection plate are processed, specifically: and removing oil stains and oxide layers within 50mm of the edges of the straight welding line and the girth welding line.

The invention has the beneficial effects that:

the method for simultaneously and reversely welding the straight welding line and the circumferential welding line in multiple sections effectively avoids the occurrence of hydrogen cracking accidents caused by stress concentration;

the straight weld seam is a single-side groove weld seam, and compared with the double-groove weld seam adopted in the prior art, the welding workload is effectively reduced, so that the probability of accidents during the pipeline welding is reduced;

the circumferential weld of the invention adopts a multi-pass surfacing welding mode, thereby reducing the occurrence of air holes and slag inclusion.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic structural view of a straight weld formed by an upper protection plate and a lower protection plate, and an annular weld formed by the upper protection plate and the lower protection plate and a mother pipe in the invention;

FIG. 2 is a schematic view of a welding process for straight seam welding according to the present invention;

FIG. 3 is a schematic view of a welding process of girth welding according to the present invention;

FIG. 4 is a schematic view of the welding of a girth weld of the present invention;

FIG. 5 is a schematic view of a straight weld formed between the upper and lower guard plates according to the present invention;

Detailed Description

As shown in fig. 1-5, the split tee assembly welding method specifically includes the following steps:

sleeving an upper protection plate 1 and a lower protection plate 2 on the outer side of a main pipe 4; wherein, the two girth welds 20 and the two straight welds 10 form a cross point A and a cross point B respectively;

in order to improve the welding quality of the straight weld joint 10 and facilitate welding, gaps between the inner sides of the upper protection plate 1 and the lower protection plate 2 and the outer side of the main pipe 4 are D which is less than or equal to 2mm as shown in FIG. 4 according to relevant regulations of SY/T6150.1-2017 in the oil and gas industry standard; as shown in FIG. 1, the distance X from two ends of the split tee flange 3 to the top of the pipe along the axial direction of the pipeline is less than or equal to 1 mm; as shown in figure 1, the distance between the central axis of the split three-way flange 3 and the pipeline axis at the position of the split three-way flange is S, and S is less than or equal to 1.5 mm.

The straight welding seam 10 and the circumferential welding seam 20 formed by the upper protection plate 1 and the lower protection plate 2 are processed, and the processing specifically comprises the following steps: removing oil stains and oxide layers within 50mm of the edges of the straight welding line 10 and the girth welding line 20;

two straight welding seams 10 formed by the upper protection plate 1 and the lower protection plate 2 are divided into a plurality of sections and are welded simultaneously;

after the two straight welding seams 10 are welded, two ends of the upper protection plate 1 and the lower protection plate 2 are respectively welded with two circumferential welding seams 20 formed by the main pipe 4; each girth weld 20 is equally divided into two sections, including an A-section girth weld including an A intersection and a B-section girth weld including a B intersection, and the A-section girth weld and the B-section girth weld are equally divided into a plurality of small sections, wherein the B-section girth weld is welded in a clockwise direction, the A-section girth weld is welded in a counterclockwise direction, and the A-section girth weld and the B-section girth weld are welded simultaneously.

Further, in order to enhance the welding quality of the straight welding seam 10, the welding of the straight welding seam 10 meets the relevant requirements, and two straight welding seams 10 formed by the upper protection plate 1 and the lower protection plate 2 are divided into multiple sections and are welded simultaneously; the two straight welding lines 10 are welded by a plurality of welders simultaneously; the stress is effectively dispersed, the problem of thermal stress concentration during unilateral welding in the prior art is solved, and the hydrogen cracking phenomenon is avoided.

The two straight weld joints 10 are equally divided into multiple sections and welded simultaneously, and specifically refer to the following steps: dividing each straight welding line 10 into three sections, and respectively welding by three welders; during welding, two straight welding seams 10 are welded simultaneously; wherein, the welding direction of the middle section of the two straight welding seams 10 is opposite, and the welding direction of the other two sections in each straight welding seam 10 is opposite and the welding is carried out to the side far away from the middle section.

Further, the straight weld 10 is a single-side groove weld, the angle of the single-side groove weld is a, and a is 40-50 °.

Compared with the prior art, the invention adopts the unilateral groove weld joint to replace the bilateral groove weld joint in the prior art as the straight weld joint 10, thereby effectively reducing the welding workload;

arranging a straight welding seam 10 into a single-side groove welding seam, wherein the angle is 40-50 degrees; compared with the prior art which adopts a bilateral groove weld with an included angle of 70 degrees, the included angle of the straight weld 10 is reduced, thereby reducing the welding workload when a welder welds;

the angle of the weld joint of the single-side groove is increased to 40-50 degrees, and the welding workload is higher than that of a welding workload of a 70-degree included angle formed by the double-side groove when the requirement of welding performance is ensured; the probability of accidents during the welding of the pipeline is reduced.

In some embodiments, to facilitate the single-sided groove forming, the angle is 45 °.

Further, when the straight welding seam 10 is welded, argon arc welding is adopted for bottoming, and the cover surface is subjected to electric arc welding, wherein the undercut depth is less than or equal to 0.5mm, the undercut continuous length is less than or equal to 50mm, and the total length of undercuts on two sides of the straight welding seam 10 is less than or equal to 10% of the total length of the welding seam;

undercut: refers to a groove or a recess generated along the base material portion of the weld toe due to improper welding parameter selection or improper operation method. The undercut will reduce the effective cross-sectional area of the base material, stress concentration may occur at the undercut, especially welding of low-alloy high-strength steel, the edge structure of the undercut is hardened, and cracks are easily caused.

Undercut depth: and during welding, the depth of the body is fused.

The mode of argon arc welding bottoming and electric arc welding cover surface effectively ensures the quality of the root of the welding seam, and the impurities such as coating welding slag can not be remained, sand holes are not easy to exist, leakage is prevented, and the welding sealing degree is high.

Preferably, a single-side V-shaped groove is adopted for a straight welding seam, the diameter of a welding rod is 3.2mm, and a formula I is calculated as (35-55) d through welding current; wherein d is the diameter of the welding rod, and I is the welding current; calculating to obtain welding current of 120-160A; and a multi-pass full-welding method is adopted, and the thickness of each welding layer is 2.0-3.0 mm.

Preferably, the straight weld joint 10 is welded in a multi-pass full-welding mode, each layer is fully welded from inside to outside, and back gouging is performed after each layer is welded, so that the welding quality can be effectively improved.

In some embodiments, the thickness b of the truncated edge is 0.5-2 mm;

in some embodiments, as shown in FIG. 2, A, B, C, D, E, F represents a welder, and the arrow indicates the direction in which the welder welds the segment; one of the straight welding lines 10 comprises a middle section Z12, a side section Z11 and a side section Z13; the other straight welding seam 10 comprises a middle section Z22, a side section Z21 and a side section Z23;

further, the two straight welding lines 10 are welded by multiple welders at the same time, specifically: dividing each straight welding seam 10 into three sections, namely a middle section Z12, a side section Z11, a side section Z13, a middle section Z22, a side section Z21 and a side section Z23; the two straight welding seams 10 are respectively welded by three welders; during welding, two straight welding seams 10 are welded simultaneously; the welding directions of the middle section Z12 and the middle section Z22 of the two straight welding lines 10 are opposite, and the welding directions of the side section Z11 and the side section Z13, the side section Z21 and the side section Z23 are opposite, and the two straight welding lines are all welded to the side far away from the middle section.

The arrangement effectively eliminates the deformation stress generated during welding; the welding quality is effectively enhanced, and the influence of the deformation stress generated during welding on the welding quality is avoided.

As shown in fig. 2, when a welder welds Z11 to the left, B welder welds Z12 to the right and C welder welds Z13 to the right, while the other F welder welds Z21 to the same direction as a welder, Z22 to E welder is opposite to B welder and Z23 to D welder is the same as C welder.

After the straight welding seam 10 is welded, the upper protection plate 1 and the lower protection plate 2 are respectively welded with two girth welding seams 20 formed by the main pipe 4; specifically, as shown in fig. 3, each circumferential weld 20 is divided into two segments in the vertical direction, including an a-segment circumferential weld including an a intersection and a B-segment circumferential weld including a B intersection, and the a-segment circumferential weld and the B-segment circumferential weld are divided into a plurality of segments, specifically: and each circumferential weld 20 is divided into two sections vertically, including an A-section circumferential weld containing an A intersection and a B-section circumferential weld containing a B intersection, and the A-section circumferential weld and the B-section circumferential weld are divided into four small sections.

Welding in a clockwise direction, specifically: the B-section girth weld is welded in sequence in the clockwise direction by taking the end part of the side, away from the split tee flange 3, of the B-section girth weld as a starting point;

welding in a counterclockwise direction, specifically: and the A-section girth weld takes the A cross point as a starting point, two welders sequentially weld in the anticlockwise direction, and after the welding is finished, the two welders sequentially weld in the anticlockwise direction by taking the end part of the section girth weld, which is far away from one side of the split tee flange 3, as a starting point.

In some embodiments, as shown in fig. 3, a1, a2, A3, a4, B1, B2, B3, B4 represent the welder code and welding sequence, with the direction of the arrows being the welding direction. When the central axis of the split tee flange 3 and the center of the circular weld 10 are on the same straight line, the circular weld 20 at two ends of the split tee is divided into two sections by the central axis of the split tee flange 3, and each section of the circular weld 20 is divided into four small sections; the B-section girth weld (namely the girth weld 20 on the left side of the central axis) is welded in a clockwise direction, the A-section girth weld (namely the girth weld 20 on the right side of the central axis) is welded in a counterclockwise direction, and during welding, each small section of girth weld 20 is finished by one welder, and eight electricians are used for welding in total; FIG. 3 illustrates that the A-staged girth weld and the B-staged girth weld begin to weld at the same time; the B-section girth welding line is welded in the clockwise direction sequentially by taking the end part far away from one side of the split three-way flange 3 as a starting point, the A-section girth welding line is welded in the anticlockwise direction sequentially by two welders from the A cross point, and after the welding is finished, the end part far away from one side of the split three-way flange 3 of the section girth welding line is taken as a starting point and is welded in the anticlockwise direction sequentially by the two welders.

The circumferential weld 20 can effectively avoid stress concentration by adopting the welding sequence, so that cracking accidents are caused; namely, as shown in fig. 3, the welding sequence on the right side of the central axis of the flange 3 is A1-A4; the welding sequence of the left side of the central axis of the flange 3 is B1-B4; wherein A1 and B1 are welded simultaneously.

Preferably, a welding rod with the diameter of 2.5mm is adopted when the circumferential weld 20 is welded, and the formula I is (35-55) d through welding current; wherein d is the diameter of the welding rod, and I is the welding current; calculating to obtain welding current of 90-120A;

as shown in fig. 4, a welding mode of multi-pass surfacing is adopted, wherein a-J in fig. 4 is a welding sequence, and the thickness of each welding layer is 2.0-3.0 mm, so that stress concentration and hydrogen cracking accidents are effectively avoided, and the problems of air holes and slag inclusion are reduced by surfacing welding.

Through the welding process of the straight welding line 10 and the circumferential welding line 20, the phenomena of stress concentration and hydrogen cracking are effectively avoided, and the situation that the split tee joint welding work fails is avoided.

Preferably, the straight weld seam 10 and the circumferential weld seam 20 are welded by manual arc welding.

Aiming at the split tee assembly welding of the invention, nondestructive testing is respectively carried out on a straight welding seam 10 welded by a welding rod with the diameter of 3.5mm and a circular welding seam 20 welded by a welding rod with the diameter of 2.5mm, and the welding quality meets the requirement.