A method for preparing a large-diameter thick-wall pipe narrow-gap laser welding joint with a layered design

Abstract

The application discloses a kind of layered design's large-diameter thick-walled pipe narrow gap laser welding joint preparation method, the inside and outside performance of pipeline welding joint is designed in view of, laser additive technology is used to prepare corrosion-resistant additive layer in pipeline inside, laser cladding technology is used to prepare high-temperature resistant cladding layer on pipeline outside, and it is successively combined with pipeline middle weld filling layer tightly, and form "additive-welding-cladding" composite narrow gap laser forming joint.The method of the application comprises: one, pipeline inside corrosion-resistant additive primer preparation;Two, pipeline middle welding filling layer preparation;Three, pipeline outside high-temperature resistant cladding surface layer preparation.The application can be aimed at the difference of large-diameter thick-walled pipe laser welding joint different parts service condition, and the performance of weld is targeted designed, solves the inherent problem of welding joint performance loss, improves the service life and safety of oil pipeline.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a large-diameter thick-wall pipe narrow-gap laser welding joint, in particular to a layered design preparation method of a large-diameter thick-wall pipe narrow-gap laser welding joint which is internally corrosion-resistant and externally high-temperature-resistant, and can be applied to the welding process of an oil transportation pipeline and belongs to the field of corrosion and protection. BACKGROUND

[0002] With the continuous development of modern technology, the demand for steel pipes is increasing, and the large-diameter thick-wall pipe as a kind of high-quality and high-efficiency pipeline material is widely used in various fields. The large-diameter thick-wall pipe has the advantages of high strength, high rigidity, wear resistance, pressure resistance, corrosion resistance and the like, and is therefore widely used in the construction of long-distance transportation pipelines for oil, natural gas, chemical raw materials and the like in the energy and chemical industry. The special service environment of such transportation pipelines puts different requirements on the internal and external performances thereof. Since the transported oil and other chemical raw materials are mostly flammable, explosive and corrosive substances, the pipeline interior needs to have excellent corrosion resistance, and since the transportation pipeline often needs to withstand high pressure, high temperature and other harsh environments, the pipeline exterior needs to have good high-temperature resistance. However, the welding position between the pipelines undergoes a rapid heating, melting and cooling process, and the chemical composition and organizational form thereof are changed, which leads to the phenomenon that the performance of the welding joint position of the pipeline is obviously lost, and the welding joint position becomes a weak position of the transportation pipeline, thereby seriously limiting the service life and safety of the oil pipeline.

[0003] By means of the layered design concept, the internal and external performances of the large-diameter thick-wall pipe narrow-gap laser welding joint are designed, a corrosion-resistant additive layer is prepared in the pipeline interior by means of laser additive technology, a high-temperature-resistant cladding layer is prepared on the pipeline exterior by means of laser cladding technology, and the two layers are in close combination with the intermediate weld filling layer of the pipeline in sequence, so as to form a “additive-welding-cladding” composite narrow-gap laser forming joint, and the performances of different regions of the large-diameter thick-wall pipe narrow-gap laser welding joint are targetedly improved. SUMMARY

[0004] In view of the problems in the prior art, the application provides a layered design preparation method of a large-diameter thick-wall pipe narrow-gap laser welding joint, a corrosion-resistant additive layer is prepared in the pipeline interior by means of laser additive technology, a high-temperature-resistant cladding layer is prepared on the pipeline exterior by means of laser cladding technology, and the two layers are in close combination with the intermediate weld filling layer of the pipeline in sequence, so as to form a “additive-welding-cladding” composite narrow-gap laser forming joint, and the performances of different regions of the large-diameter thick-wall pipe narrow-gap laser welding joint are targetedly improved.

[0005] The application is implemented by the following technical scheme:

[0006] The application provides a preparation method of a large-diameter thick-wall pipe narrow-gap laser welding joint with a layered design.

[0007] (1) A laser scanner is used to collect the bevel geometric size of a stainless steel pipe to be welded and perform image processing, and a corresponding stainless steel pipe bevel model is constructed;

[0008] (2) The laser focal point action position is determined based on the pipe bevel model, the additive process parameters of the corrosion-resistant primer layer are input, the corrosion-resistant additive primer layer is prepared, and the corresponding corrosion-resistant additive primer layer height is obtained;

[0009] (3) The laser focal point offset height of the welding filler layer is calculated based on the corrosion-resistant additive primer layer height, the laser focal point position is adjusted, the filler layer welding process parameters are input, the welding filler layer is prepared, the corresponding weld filler layer height is obtained, the total weld height is calculated, and when the total weld height is greater than the bevel height, the next step is performed, otherwise the weld filler layer welding process is repeated;

[0010] (4) The laser focal point offset height of the high-temperature cladding cover layer is calculated based on the weld cover layer height, the laser focal point position is adjusted, the corrosion-resistant cover layer cladding process parameters are input, and the corrosion-resistant cladding cover layer is prepared;

[0011] Further, the corrosion-resistant additive primer layer / welding filler layer / high-temperature cladding cover layer size model is a relationship model between the cross-sectional area, fusion width and residual height of a single additive / welding / cladding layer and the wire / sand speed, laser power and scanning / welding / cladding speed, and the mathematical expression formula is as follows:

[0012] S d =a1P+b1v w +c1v f

[0013] h d =a2P+b2v w +c2v f

[0014] D d =a3P+b3v w +c3v f

[0015] Wherein, S d , h d , D d , P, v w and v fA1, A2, A3, B1, B2, B3, C1, C2 and C3 are constants and related to material quality, respectively, single-pass additive / welding / fusion layer cross-sectional area, reinforcement, fusion width, laser power, scanning / welding / fusion speed and wire / powder feeding speed;

[0016] Further, the input of the base layer additive / filler layer welding / cover layer fusion process parameters is realized through the interrelated additive process knowledge base, welding process knowledge base and fusion process knowledge base, and the corresponding base layer / filler layer / cover layer size model is established based on the process parameters to obtain the corresponding additive / welding / fusion layer height, including:

[0017] Based on the established pipe bevel model, the land of the bevel and the gap size between the bevels are extracted, the laser additive process knowledge base is queried, and the corrosion-resistant base layer additive process parameters are obtained;

[0018] Based on the corrosion-resistant base layer additive / filler layer welding / high-temperature cover layer fusion process parameters, the corrosion-resistant additive base layer / welding filler layer / high-temperature fusion cover layer size model is established to obtain the corrosion-resistant additive base layer / welding filler layer / high-temperature fusion cover layer height;

[0019] Further, the corrosion-resistant additive base layer height and the welding filler layer laser focal point offset height are solved according to the following equation, and the specific equation is as follows:

[0020]

[0021] h l1 =h1

[0022] Wherein, D d1 , S d1 , d, h1 and h l1 represent the additive base layer fusion width, the additive base layer cross-sectional area, the bevel bottom width, the corrosion-resistant additive base layer height and the welding filler layer laser focal point offset height, respectively;

[0023] Further, the welding filler layer height and the next welding filler layer laser focal point offset height are solved according to the following equation, and the specific equation is as follows:

[0024]

[0025] h li =h 1+i

[0026] Wherein, D d1+i , D di , h 1+i , S d1+i and h lirespectively represent the i-th layer welding filler layer fusion width, the i-1-th layer welding filler layer fusion width, the i-th layer welding filler layer weld height, the i-th layer welding filler layer cross-sectional area and the next welding filler layer laser focal point offset height;

[0027] Further, the total weld height is solved according to the following equation, and the specific equation is as follows:

[0028] H = ∑h i i = 1, 2, 3,..., n

[0029] Wherein, H represents the total weld height.

[0030] Further, the total weld height satisfies H≥H h , the welding process of the filler layer is completed;

[0031] Further, the welding cover layer height and the high-temperature-resistant cladding cover layer laser focal point offset height are solved according to the following equation, and the specific equation is as follows:

[0032] h ln = h 1+n

[0033] Wherein, h 1+n and h ln respectively represent the welding cover layer height and the high-temperature-resistant cladding cover layer laser focal point offset height.

[0034] Further, the pipe bevel model mainly includes: the bevel bottom width d, the bevel height H h and the blunt edge h0.

[0035] Further, the corrosion-resistant additive primer layer is mainly prepared by adding trace amounts of nano Ta particles through laser additive process.

[0036] Further, the high-temperature-resistant cladding cover layer is mainly prepared by laser cladding TiC nano welding wire.

[0037] Further, the corrosion-resistant additive primer layer, the welding filler layer and the corrosion-resistant cladding cover layer are all simplified as trapezoids.

[0038] The beneficial effects of the present application are: for the performance loss of large-diameter thick-walled pipe narrow-gap laser welded joints, which leads to the fact that the weak performance part cannot meet the complex service requirements of internal corrosion resistance and external high-temperature resistance of the transportation pipeline, the method respectively uses laser additive technology to prepare a corrosion-resistant additive layer inside the pipeline, uses laser cladding technology to prepare a high-temperature-resistant cladding layer outside the pipeline, and is sequentially combined with the middle weld filler layer of the pipeline to form a "additive-welding-cladding" composite narrow-gap laser forming joint, realizes the targeted improvement of the performance of different regions of the large-diameter thick-walled pipe narrow-gap laser welded joint, and thus improves the service performance. Attached Figure Description

[0039] Figure 1 This is a flowchart illustrating the fabrication process of a layered design joint for laser welding of large-diameter, thick-walled tubes with narrow gaps, as described in this invention.

[0040] Figure 2 This is a schematic diagram of the layered design joint for laser welding of large-diameter thick-walled pipes with narrow gaps, as described in this invention.

[0041] Figure 3 This is a schematic diagram of the corrosion-resistant additive manufacturing underlayer for the large-diameter thick-walled pipe narrow-gap laser welding joint described in this invention;

[0042] Figure 4 This is a schematic diagram of the high-temperature resistant fusion coating layer of the large-diameter thick-walled pipe narrow-gap laser welding joint described in this invention;

[0043] In the figure, 1-pipe bevel; 2-pipe I to be welded; 3-pipe II to be welded; 4-corrosion resistant additive underlayer; 5-welding filler layer; 6-welding capping layer; 7-high temperature resistant fusion capping layer; 8-nano Ta particles; 9-laser beam; 10-TiC nano welding wire. Detailed Implementation

[0044] This invention provides a method for preparing a narrow-gap laser-welded joint for a large-diameter, thick-walled tube with a layered design. To make the objectives, effects, and technical solutions of this invention clearer, the invention will be described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. For ease of description, the accompanying drawings show only the parts relevant to this invention, not all of the structures.

[0045] The following is in conjunction with the appendix Figure 1 , 2 Sections 3 and 4 provide a detailed description of the method for preparing a layered design for a narrow-gap laser welding joint of a large-diameter, thick-walled tube according to the present invention:

[0046] Narrow-gap laser welding and laser cladding experiments were conducted on large-diameter, thick-walled pipes. The pipes to be welded, I(2) and II(3), had an outer diameter of 1088 mm, an inner diameter of 900 mm, and a length of 400 mm. The experiments used an RFL-C12000XZ laser with a maximum output power of 12000 W, and an IPGD50 laser head to complete the narrow-gap laser additive manufacturing, welding, and cladding processes.

[0047] Combination Figure 1 The flowchart and Figure 2 The schematic diagram of the welded joint shown illustrates a method for fabricating a narrow-gap laser welded joint for a large-diameter, thick-walled tube with a layered design, comprising the following steps:

[0048] (1) using a laser scanner to collect the geometric size of the bevel of the stainless steel pipeline to be welded (1) and perform image processing, and constructing a corresponding stainless steel pipeline bevel model;

[0049] (2) determining the laser focal point action position based on the pipeline bevel model, inputting the corrosion-resistant primer layer additive process parameters, completing the preparation of the corrosion-resistant additive primer layer (4), and obtaining the corresponding corrosion-resistant additive primer layer height;

[0050] (3) calculating the laser focal point offset height of the welding filler layer based on the corrosion-resistant additive primer layer height, completing the adjustment of the laser focal point position, inputting the filler layer welding process parameters, completing the preparation of the welding filler layer (5), obtaining the corresponding weld filler layer height, and calculating the total weld height. When the total weld height is greater than the bevel height, the next step is performed, otherwise the weld filler layer welding process is repeated;

[0051] (4) calculating the laser focal point offset height of the high-temperature cladding cover layer based on the weld cover layer height, completing the adjustment of the laser focal point position, inputting the corrosion-resistant cover layer cladding process parameters, and completing the preparation of the corrosion-resistant cladding cover layer (7);

[0052] Specifically, the corrosion-resistant additive primer layer / welding filler layer / high-temperature cladding cover layer size model is a relationship model between the cross-sectional area, fusion width and excess height of a single additive / welding / cladding layer and the wire / powder feeding speed, laser power and scanning / welding / cladding speed, and the mathematical expression formula is as follows:

[0053] S d =a1P+b1v w +c1v f

[0054] h d =a2P+b2v w +c2v f

[0055] D d =a3P+b3v w +c3v f

[0056] Wherein, S d , h d , D d , P, v w and v f are the cross-sectional area, excess height, fusion width, laser power, scanning / welding / cladding speed and wire / powder feeding speed of a single additive / welding / cladding layer, and a1, a2, a3, b1, b2, b3, c1, c2 and c3 are constants related to the material;

[0057] Specifically, the input of the primer layer additive / filler layer welding / cover layer cladding process parameters is realized through the interrelated additive process knowledge base, welding process knowledge base and cladding process knowledge base, and a corresponding primer layer / filler layer / cover layer size model is established based on the process parameters to obtain the corresponding additive / welding seam / cladding layer height, including:

[0058] Based on the established pipe groove model, the land of the groove and the groove gap size are extracted, the laser additive process knowledge base is queried, and the corrosion-resistant primer layer additive process parameters are obtained;

[0059] Based on the corrosion-resistant primer layer additive / filler layer welding / high-temperature cover layer cladding process parameters, the corrosion-resistant additive primer layer / welding filler layer / high-temperature cladding cover layer size model is established to obtain the corrosion-resistant additive primer layer / welding filler layer / high-temperature cladding cover layer height;

[0060] Specifically, the corrosion-resistant additive primer layer height and the welding filler layer laser focal point offset height are solved according to the following equation, and the specific equation is as follows:

[0061]

[0062] h l1 =h1

[0063] Wherein, D d1 , S d1 , d, h1 and h l1 respectively represent the additive primer layer melt width, the additive primer layer cross-sectional area, the groove bottom width, the corrosion-resistant additive primer layer height and the welding filler layer laser focal point offset height;

[0064] Specifically, the welding filler layer height and the next welding filler layer laser focal point offset height are solved according to the following equation, and the specific equation is as follows:

[0065]

[0066] h li =h 1+i

[0067] Wherein, D d1+i , D di , h 1+i , S d1+i and h li respectively represent the i-th layer welding filler layer melt width, the i-1-th layer welding filler layer melt width, the i-th layer welding filler layer weld height, the i-th layer welding filler layer cross-sectional area and the next welding filler layer laser focal point offset height;

[0068] Specifically, the total weld height is solved according to the following equation, and the specific equation is as follows:

[0069] H = ∑h i i = 1, 2, 3,..., n

[0070] Wherein, H represents the total height of the weld.

[0071] Specifically, the total height of the weld satisfies H ≥ H h , the welding process of the filling layer is completed;

[0072] Specifically, the welding cover layer height and the high-temperature-resistant cladding cover layer laser focal point offset height are solved according to the following equation, and the specific equation is as follows:

[0073] h ln = h 1+n

[0074] Wherein, h 1+n and h ln respectively represent the welding cover layer height and the high-temperature-resistant cladding cover layer laser focal point offset height.

[0075] Specifically, the pipe groove model mainly includes a groove bottom width d, a groove height H h and a root face h0.

[0076] Specifically, the corrosion-resistant additive primer layer (4) is mainly prepared by adding trace amounts of nano Ta particles (8) through a laser additive process, as shown in Figure 3 .

[0077] Specifically, the high-temperature-resistant cladding cover layer (7) is mainly prepared by laser cladding TiC nano welding wire (10), as shown in Figure 4 .

[0078] Specifically, the corrosion-resistant additive primer layer (4), the welding filling layer (5) and the corrosion-resistant cladding cover layer (7) are all simplified as trapezoids.

[0079] Specifically, the process parameters for preparing the corrosion-resistant additive primer layer of the application are as follows: the laser power is 8kW, the powder feeding speed is 5m / min, and the scanning speed is 0.5m / min.

[0080] Specifically, the process parameters for preparing the welding filling layer of the application are as follows: the laser power is 8-10kW, the wire feeding speed is 9-11m / min, the welding speed is 0.5-0.8m / min, and the maximum depth of the welding filling layer is controlled in the range of 2.0-3.0mm.

[0081] Specifically, the high-temperature-resistant cladding surface layer adopts the process parameters: the laser power is 0.4 kW, the wire feeding speed is 6 m / min, the cladding speed is 0.5 m / min, and the maximum depth control range of the high-temperature-resistant cladding surface layer is 0.5-0.8 mm.

Claims

1. A method for manufacturing a narrow gap laser welded joint of a large diameter thick wall pipe with a layered design, characterized in that, The preparation method comprises the following steps: (1) collecting the geometric size of the bevel of the stainless steel pipe to be welded by using a laser scanner and performing image processing to construct a corresponding stainless steel pipe bevel model; (2) determining the laser focal point action position based on the pipe bevel model, inputting the corrosion-resistant primer layer additive process parameters, completing the preparation of the corrosion-resistant additive primer layer, and obtaining the corresponding corrosion-resistant additive primer layer height; (3) calculating the laser focal point offset height of the welding filler layer based on the corrosion-resistant additive primer layer height, adjusting the laser focal point position, inputting the filler layer welding process parameters, completing the preparation of the welding filler layer, obtaining the corresponding weld filler layer height, and calculating the total weld height; when the total weld height is greater than the bevel height, the next step is performed, otherwise the weld filler layer welding process is repeated; (4) calculating the laser focal point offset height of the high-temperature cladding cover layer based on the weld cover layer height, completing the adjustment of the laser focal point position, inputting the high-temperature cladding cover layer cladding process parameters, and completing the preparation of the high-temperature cladding cover layer; The size model of the corrosion-resistant additive primer layer / welding filler layer / high-temperature cladding cover layer is a relationship model between the cross-sectional area, fusion width and excess height of the single-pass additive / welding / cladding layer and the wire / sand feeding speed, laser power and scanning / welding / cladding speed, and the mathematical expression formula is as follows: S d = a1P + b1v w + c1v f h d = a2P + b2v w + c2v f D d = a3P + b3v w + c3v f wherein S d , h d , D d , P, v w and v f are the single-pass additive / welding / cladding layer cross-sectional area, reinforcement, weld width, laser power, scanning / welding / cladding speed and wire / powder feed speed, respectively, and a1, a2, a3, b1, b2, b3, c1, c2 and c3 are constants and are related to the material; The input of the primer layer additive / filler layer welding / cover layer cladding process parameters is realized through the mutually related additive process knowledge base, welding process knowledge base and cladding process knowledge base, and the corresponding primer layer / filler layer / cover layer size model is established based on the process parameters to obtain the corresponding additive / welding / cladding layer height, including: The size of the bevel land and the bevel gap is extracted based on the established pipe bevel model, the additive process knowledge base is queried, and the corrosion-resistant primer layer additive process parameters are obtained; The corrosion-resistant additive primer layer / welding filler layer / high-temperature cladding cover layer size model is established based on the corrosion-resistant primer layer additive / filler layer welding / high-temperature cover layer cladding process parameters to obtain the corrosion-resistant additive primer layer / welding filler layer / high-temperature cladding cover layer height; The corrosion-resistant additive primer layer height and the welding filler layer laser focal point offset height are solved according to the following equation, and the specific equation is as follows: h l1 = h1 wherein D d1 , S d1 , d, h1 and h l1 respectively represent the additive backing layer fusion width, the additive backing layer cross-sectional area, the bevel base width, the corrosion-resistant additive backing layer height, and the welding filler layer laser focal point offset height; The welding filler layer height and the next welding filler layer laser focal point offset height are solved according to the following equation, and the specific equation is as follows: h li = h 1+i wherein D d1+i , D di , h 1+i , S d1+i , and h li represent the melt width of the i-th weld filler layer, the melt width of the i-1-th weld filler layer, the weld height of the i-th weld filler layer, the cross-sectional area of the i-th weld filler layer, and the offset height of the laser focal point of the next weld filler layer, respectively. The total weld height is solved according to the following equation, and the specific equation is as follows: H =∑h i i = 1, 2, 3,..., n Wherein, H represents the total weld height; The total height of the weld satisfies H≥H h When the filling layer is completed, the welding process is finished. The weld cover layer height and the high-temperature cladding cover layer laser focal point offset height are solved according to the following equation, and the specific equation is as follows: h ln = h 1+n where h 1+n and h ln respectively represent the height of the weld cap layer and the height of the laser focal point offset of the high-temperature-resistant cladding cap layer.

2. The method of claim 1, wherein the method is characterized by: The pipe bevel model mainly comprises a bevel bottom width d, a bevel height H, and a root face h0. h and a root face h0.

3. The method of claim 1, wherein the method further comprises: The corrosion-resistant additive primer layer is mainly prepared by adding trace amounts of nano Ta particles through a laser additive process.

4. The method of claim 1, wherein the method further comprises: The high-temperature cladding cover layer is mainly prepared by laser cladding TiC nano welding wire.

5. The method of claim 1, wherein the method further comprises: The corrosion-resistant additive primer layer, the welding filler layer and the corrosion-resistant cladding cover layer are all simplified as trapezoids.

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