CN101323041B - Narrow-gap pulse melting extreme gas shielded automatic welding method for petroleum kelly - Google Patents

Abstract

The invention discloses an automatic welding method with a narrow-gap pulse consumable electrode and gas protection of petroleum kellies and includes the steps that firstly, round auxiliary blocks are respectively arranged on end surfaces of two kellies to be welded to cause a groove of a whole ring narrow-gap welded joint of the kelly to become a regular ring narrow-gap groove from the irregularity; then the automatic welding method with gas protection and the pulse consumable electrode is used for welding, and after the welding is finished, the auxiliary blocks and the raised part of the welded joint are processed to keep the original shapes of the kellies. As the round auxiliary blocks are respectively arranged on end surfaces of two kellies to be welded, the groove of the whole ring narrow-gap welded joint of the kelly is caused to become a regular ring narrow-gap groove from the irregularity, the method ensures the gas protective effect in the welding from a bottom drawing arc to the surface and the stability of the electric arc burning and the molten pool state of the electric arc and improves the quality of the welded joints.

Description

Narrow-gap pulse melting extreme gas shielded automatic welding method for petroleum kelly

technical field

The invention relates to an automatic welding method for petroleum drill pipes, in particular to an automatic welding method for narrow gap pulse melting extreme gas protection of petroleum kelly pipes.

Background technique

There are two types of section shapes of the oil kelly, square and hexagonal. Due to the limitation of the section shape, manual arc welding has been used to repair the oil kelly for a long time. The kelly is a thick-walled pipe body, which needs continuous multi-layer circular seam welding. Obviously, the manual arc welding method takes a long time to weld, and each welding repair takes about two hours. The production efficiency is low, the labor intensity is high, and the welding cost is high. Welding quality cannot be guaranteed.

The document "Development of Automatic Kelly Circular Seam Welding Machine Jiang Shuying, Sun Yongxing, Wang Yubin, Xu Jingnian "Petroleum Machinery" 2006, Volume 34, No. 12, Page 41-43" discloses an automatic kelly circular seam welding machine. When using this welding machine to weld the kelly, the bottom layer is welded with argon tungsten arc welding, and the multi-layer filling welding is performed with _CO2 gas shielded welding. However, since the section shape of the kelly is square or hexagonal, when the continuous multi-layer welding from the bottom layer to the corner position of the square or hexagonal, the groove of the entire annular narrow gap weld has obvious inhomogeneity, that is, in The edge position is a narrow gap weld bevel, but it is not a narrow gap weld bevel at the plane position, which makes it impossible to maintain the stability of arc combustion and gas protection and the normal and uniform molten pool shape during welding, resulting in molten pool metal The form of flow and protective air flow diverges, which makes the formation of weld seam deteriorate sharply, and a large number of pores, inclusions and incomplete penetration defects appear, which reduces the quality of weld seam.

Contents of the invention

In order to overcome the deficiency of low weld seam quality when welding kelly in the prior art, the present invention provides a narrow-gap pulse melting extreme gas shielded automatic welding method for petroleum kelly. The circular auxiliary blocks are arranged separately, so that the groove of the entire annular narrow gap weld of the kelly is changed from irregular to regular annular narrow gap groove, which can improve the quality of the weld.

The technical solution adopted by the present invention to solve the technical problem: a narrow-gap pulse melting extreme gas shielded automatic welding method for petroleum kelly, which is characterized in that it includes the following steps:

(a) Process the end face of the kelly to be welded into a half-U shape, and form a U-shaped groove at the rear joint when the end face of the kelly is aligned with the weld;

(b) Prepare two circular auxiliary blocks with a thickness of 20-25mm, diameter Φ=D+6mm, where D is the diagonal length of the kelly, and the shape of the inner hole is the same as that of the kelly to be welded;

(c) Install the auxiliary blocks on the two side walls of the U-shaped groove on the end face of the kelly to be welded, align the inner surface of the auxiliary blocks with the side wall of the U-shaped groove, and pass the outer sides of the auxiliary blocks through the drill pipe body spot welding;

(d) Adjust the falling of the welding torch so that the welding wire points to the bottom position of the U-shaped groove. The lower edge of the gas shield of the welding torch is in contact with the outer circle of the auxiliary block. When the kelly rotates, the gas shield moves along the outer circle of the two auxiliary blocks. surface for smooth and uniform movement;

(e) Set welding parameters, wire feeding speed 3.16m/min, welding speed 0.296m/min, pulse current 110-150A, base value current 50A, argon gas flow rate 2000L/h, carbon dioxide gas flow rate 120L/h, when Ar And CO2 gas flows out from the protective cover, the kelly rotates, and the welding wire is sent out at a constant speed. After the arc is ignited between the end of the welding wire and the bottom layer of the U-shaped groove, multi-layer welding will continue. After each layer is welded, the welding torch will automatically lift 3mm , until the welding to the surface stops;

(f) After the welding is completed, the auxiliary block and the raised weld seam are processed to keep the original shape of the kelly.

The beneficial effects of the present invention are: the present invention aims at the problem of low weld seam quality during kelly welding, and respectively sets circular auxiliary blocks on the end faces of the two kelly pipes to be welded, so that the entire ring-shaped narrow gap weld of the kelly The groove has changed from irregular to regular annular narrow gap groove, which ensures the gas protection effect, the stability of arc combustion and the stability of arc molten pool shape when arc welding from the bottom layer to the surface layer, and improves the quality of weld seam .

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Description of drawings

Fig. 1 is a schematic diagram of Embodiment 1 of the present invention.

Fig. 2 is a cross-sectional view taken along line A of Fig. 1 .

In the figure, 1-welding torch; 2-gas shield; 3-right auxiliary block; 4-left auxiliary block; 5-welding wire; 6-U-shaped groove; 7-drill pipe; 8-spot welding.

Detailed ways

Example 1: Narrow-gap pulse melting automatic welding with extreme gas shielding for square kelly.

Referring to Figures 1-2, the end face of the square kelly 7 to be welded is processed into a half-U shape, and the end face of the kelly is aligned with the rear joint during welding to be processed into a U-shaped groove 6 with 2 mm of blunt edge left .

Prepare the right auxiliary block 3 and the left auxiliary block 4. The auxiliary block is made of No. 20 steel with a round shape and a thickness of 20-25mm. The inner hole is square and the size of the inner hole is larger than the cross-sectional shape of the square kelly to be welded. 0.2～0.3mm, its diameter Φ=D+6mm, where D is the diagonal length of the square kelly.

Install the right auxiliary block 3 and the left auxiliary block 4 on the two side walls of the U-shaped groove 6 on the end face of the drill pipe to be welded respectively, and the inner surface of the auxiliary block should be aligned with the side wall of the U-shaped groove 6, and then use manual arc welding The outer sides of the right auxiliary block 3 and the left auxiliary block 4 are respectively fixed with the drill pipe 7 body by spot welding 8 .

Adjust the falling of the welding torch 1 so that the welding wire 5 points to the bottom position of the U-shaped groove 6. The lower edge of the welding torch gas shield 2 is in contact with the outer circles of the right auxiliary block 3 and the left auxiliary block 4. It is required that when the kelly rotates, the gas The protective cover can move smoothly and evenly along the outer circular surfaces of the two auxiliary blocks.

Set the welding specification parameters as wire feeding speed 3.16m/min, welding speed 0.296m/min, pulse current 110-150A, base current 50A, argon gas flow rate 2000L/h, carbon dioxide gas flow rate 120L/h. Press the start button, when the Ar and CO ₂ gases flow out from the protective cover, the kelly 7 rotates, the welding wire 5 is sent out at a constant speed, and after the arc is ignited between the end of the welding wire and the bottom layer of the welding U-shaped groove 6, multi-layer welding will continue. For welding, every time a layer is welded, the welding torch is automatically lifted by 3mm to ensure that the arc length remains constant until the welding stops at the surface layer.

After the welding is completed, the auxiliary block and the raised weld seam are processed away to restore the original shape of the square kelly.

Example 2: Narrow-gap pulse melting automatic welding with extreme gas shielding for six kelly pipes.

Except that the inner holes of the right auxiliary block and the left auxiliary block are in a hexagonal shape, all the others are the same as in embodiment 1.

For the square and hexagonal drill pipes welded by the method of Example 1 and Example 2, the welded seam joints are tested by ultrasonic flaw detection after heat treatment respectively, and the quality of the welded seam meets the requirements of the "GB/T 15830-1995" standard.

The researchers conducted a mechanical performance test on the welded joint, and the mechanical performance data of the weld, heat-affected zone and fusion line are shown in Tables 1 and 2. The mechanical performance indicators in the table all meet the requirements for use.

Table 1. Impact test results

Table 2. Tensile test results

Claims (2)

1. A kind of petroleum kelly narrow-gap pulse melting extreme gas protection automatic welding method is characterized in that comprising the following steps: (a) Process the end face of the kelly to be welded into a half-U shape, and form a U-shaped groove at the rear joint when the end face of the kelly is aligned with the weld; (b) Prepare two circular auxiliary blocks with a thickness of 20-25mm, diameter Φ=D+6mm, where D is the diagonal length of the kelly, and the inner hole is the same shape as the kelly to be welded; (c) Install the auxiliary blocks on the two side walls of the U-shaped groove on the end face of the kelly to be welded, align the inner surface of the auxiliary blocks with the side wall of the U-shaped groove, and pass the outer sides of the auxiliary blocks through the drill pipe body spot welding; (d) Adjust the falling of the welding torch so that the welding wire points to the bottom position of the U-shaped groove. The lower edge of the gas shield of the welding torch is in contact with the outer circle of the auxiliary block. When the kelly rotates, the gas shield moves along the outer circle of the two auxiliary blocks. surface for smooth and uniform movement; (e) Set welding parameters, wire feeding speed 3.16m/min, welding speed 0.296m/min, pulse current 110-150A, base value current 50A, argon gas flow rate 2000L/h, carbon dioxide gas flow rate 120L/h, when Ar And _CO2 gas flows out from the protective cover, the kelly rotates, and the welding wire is sent out at a constant speed. After the arc is ignited between the end of the welding wire and the bottom layer of the welding U-shaped groove, multi-layer welding will continue. After each layer is welded, the welding torch is automatically lifted 3mm until the welding reaches the surface layer; (f) After the welding is completed, the auxiliary block and the raised weld seam are processed to keep the original shape of the kelly. 2. The narrow-gap pulse melting extreme gas shielded automatic welding method for petroleum kelly according to claim 1, characterized in that: said auxiliary block is made of No. 20 steel.

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