Method for high-frequency welding of pipe fittings through aluminum-silicon coating plates with different thicknesses

Abstract

The invention relates to a welding method for rolling an unequal-thickness plate into a pipe fitting, in particular to a method for high-frequency welding of the pipe fitting by an unequal-thickness aluminum-silicon coating plate, which comprises the following steps of: rolling areas needing to be welded on two sides of the unequal-thickness plate so as to reduce the difference value of the thicknesses on the two sides, rolling an opening angle and crushing an aluminum-silicon coating; rolling the unequal-thickness plate into a circular pipe; carrying out high-frequency welding on a longitudinal seam of the circular tube; and carrying out post-treatment on the round pipe. According to the method for high-frequency welding of the pipe fittings through the aluminum-silicon coating plates with the different thicknesses, the two side edges, used for welding, of the plates with the different thicknesses are rolled, so that the height difference of welding is reduced, the plates with the different thicknesses tend to be equal in thickness, then reliable welding is guaranteed, only the strength requirement of the pipes can be met, meanwhile, the welding cost is reduced, and the production efficiency is improved. In addition, the aluminum-silicon coating at the weld joint is eliminated through rolling, the microcosmic metallographic phase of the weld joint is qualified, the process can be simplified, meanwhile, the welding quality can be guaranteed, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to a welding method for rolling a pipe fitting from plates with unequal thicknesses, and particularly to a method for high-frequency welding of pipe fittings made of aluminum-silicon coated plates with unequal thicknesses. Background Art

[0002] Variable-thickness plates are also known as rolled plates with unequal thicknesses, abbreviated as TRB (tailored rolled blanks) abroad and VRB (variable-thickness rolled blanks) in China. Researched by a certain university in Germany, during the steel plate rolling process, by controlling the roll gap, the thickness of the plate changes in the rolling direction, and is controlled in real time by a computer to obtain the required combination of material plate thicknesses. Since the thickness combination of VRB plates can be freely adjusted, it can be adjusted according to the stress mode of automotive parts to achieve equal-strength replacement, reduce the number of parts, expand the design space of automotive parts, and realize the lightweight of automobiles.

[0003] To avoid oxidation and decarburization during the heating and transfer of hot stamping steel, the hot stamping steel aluminum-silicon coating technology has been developed and has been widely applied in the global automotive industry. Some of them use pipes, so it is necessary to weld the steel plate after coiling it into a circle.

[0004] Welded pipes are widely used in various internal structural parts of automobiles. At present, most welded pipes are produced by uncoiling a narrow coil and continuously forming it with multiple rolls, and then using high-frequency welding. However, this kind of welded pipe is processed from plates with uniform thickness, that is, processed from plates with equal thickness. For pipes coiled from plates with unequal thicknesses, high-frequency welding cannot be used, and usually laser welding is used. For example, a processing method for welded pipes with unequal thicknesses disclosed in CN 104772566A uses laser welding to solve the problem that high-frequency welding cannot be used. Due to the high equipment cost of laser welding, the penetration ability of thick-walled pipes is limited, and the requirements for weld gaps are relatively high, so auxiliary equipment needs to be improved. Moreover, the speed of laser welding is slow, and high-speed continuous welding cannot be carried out. The overall welding efficiency is lower than that of high-frequency welding, and the welding cost is also significantly higher than that of high-frequency welding. In addition, the aluminum-silicon coating at the weld needs to be removed before laser welding, otherwise the welding quality cannot meet the requirements. Since the aluminum-silicon coating needs to be removed, there are more processes and the process is complex, increasing the cost. Summary of the Invention

[0005] To solve the above problems, the present invention provides a method for high-frequency welding of pipe fittings made of aluminum-silicon coated plates with unequal thicknesses. The specific technical solution is as follows:

[0006] A method for high-frequency welding of pipe fittings made of aluminum-silicon coated plates with unequal thicknesses includes the following steps:

[0007] Roll the areas on both sides of the unequal-thickness plate that need to be welded to reduce the thickness difference between the two sides, while rolling out an opening angle and crushing the aluminum-silicon coating;

[0008] Roll the unequal-thickness plate into a round tube;

[0009] Perform high-frequency welding on the longitudinal seam of the round tube;

[0010] Perform post-treatment on the round tube.

[0011] Preferably, the thickness on both sides of the unequal-thickness plate is rolled to the minimum thickness of the original unequal-thickness plate + 0.3 - 0.7 mm.

[0012] Preferably, when rolling both sides of the unequal-thickness plate, it includes rough rolling first and then finish rolling.

[0013] Preferably, blow air on the rolling area during rolling.

[0014] Preferably, roll both sides of the unequal-thickness plate within a width range of 1.5 mm.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] A method for high-frequency welding of pipe fittings with an unequal-thickness aluminum-silicon coated plate provided by the present invention rolls the two sides of the unequal-thickness plate used for welding to reduce the height difference of welding, making it tend to be of equal thickness, thereby ensuring reliable welding, only meeting the strength requirements of the pipe, while reducing the welding cost. In addition, rolling eliminates the aluminum-silicon coating at the weld, and the weld microstructure metallography is qualified, which can not only simplify the process, but also ensure the welding quality and reduce the cost. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of rolling both sides of the unequal-thickness plate.

[0018] Figure 2 It is a cross-sectional metallographic diagram of a 1.6-mm thick plate rolled into a circle and welded. Detailed Embodiments

[0019] The present invention will be further described in conjunction with the accompanying drawings.

[0020] As Figure 1 shown, a method for high-frequency welding of pipe fittings with an unequal-thickness aluminum-silicon coated plate includes the following steps:

[0021] Roll the areas on both sides of the unequal-thickness plate that need to be welded to reduce the thickness difference between the two sides, while rolling out an opening angle and crushing the aluminum-silicon coating;

[0022] Roll the unequal-thickness plate into a round tube;

[0023] High frequency welding of the longitudinal seam of the round tube;

[0024] Post-process the round tube.

[0025] The thickness on both sides of the unequal thickness plates is rolled to the minimum thickness of the original unequal thickness plates + 0.3 to 0.7 mm.

[0026] Rolling the two sides of plates of unequal thickness includes rough rolling followed by finish rolling.

[0027] During rolling, air is blown into the rolling area.

[0028] Rolling is performed on both sides of plates of different thickness within a width of 1.5 mm.

[0029] At the same time, after rolling the aluminum silicon coating within 1.5mm of the edge, high-pressure gas is blown to increase the opening angle and then frequency conversion and high-frequency welding are performed.

[0030] The round tube is post-processed, including cooling the round tube, sizing and straightening, and cutting.

[0031] Before rolling, the process also includes: loading, shearing, storing and feeding.

[0032] Rolling into round tubes, variable frequency high frequency welding of longitudinal seams, cooling the round tubes, sizing and straightening, and cutting are all existing technologies and will not be described in detail here.

[0033] The rolling of the two sides of the plates of unequal thickness is carried out before the plates are rolled.

[0034] like Figure 2 As shown, according to the cross-sectional metallographic diagram of the 1.6 mm thick plate rolled welding, it can be seen that the welding quality is good and the weld is uniform.

[0035] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the protection scope of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific implementations of the present invention without paying creative labor, and these methods will fall within the protection scope of the claims of the present invention.

Claims

1. A method for high-frequency welding pipe fittings of aluminum-silicon coated plates of unequal thickness, characterized in that: The following steps are involved: Roll the areas on both sides of the plates of unequal thickness that need to be welded to reduce the difference in thickness on both sides, while rolling out the opening angle and rolling off the aluminum-silicon coating; Rolling plates of different thicknesses into round tubes; High frequency welding of the longitudinal seam of the round tube; Post-process the round tube.

2. The method for high-frequency welding pipe fittings of aluminum-silicon coated plates of unequal thickness according to claim 1 is characterized in that: The thickness of both sides of the unequal thickness plate is rolled to the minimum thickness of the original unequal thickness plate + 0.3 to 0.7 mm.

3. The method for high-frequency welding pipe fittings of aluminum-silicon coated plates of unequal thickness according to claim 1 is characterized in that: Rolling the two sides of plates of unequal thickness includes rough rolling followed by finish rolling.

4. The method for high-frequency welding pipe fittings of aluminum-silicon coated plates of unequal thickness according to claim 1 is characterized in that: During rolling, air is blown into the rolling area.

5. The method for high-frequency welding pipe fittings of aluminum-silicon coated plates of unequal thickness according to claim 1 is characterized in that: Rolling is performed on both sides of plates of unequal thickness within a width of 1.5 mm.

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