CN103192149B - The welding method of X80 pipe line steel laser braze welding - Google Patents

Abstract

The invention relates to a welding method for laser brazing of X80 pipeline steel, which belongs to the field of advanced manufacturing technology. The present invention uses a high-energy laser source as a unified preheating light source and welding light source, uses reflectors, beam splitters, and focusing mirrors to perform steps on the laser including laser reflection, beam splitting, energy distribution, and refocusing. The position achieves the purpose of distributing the energy of the laser beam, adjust the wedge angle of the beam splitter, adjust the distance between the front and rear laser beams, and form two front and rear laser beams, the front laser beam is used as a preheating beam, and the rear laser beam is used as a welding beam, and the preheating beam is used During preheating, a concave lens should be used to disperse the energy of the preheating beam, which solves the problem of electrochemical corrosion caused by uneven weld structure caused by conventional welding.

Description

Laser Brazing Welding Method of X80 Pipeline Steel

technical field

The invention relates to a welding method for laser brazing of X80 pipeline steel, belongs to the field of advanced manufacturing technology, and solves the problem that electrochemical corrosion is easily caused by uneven weld seam structure caused by conventional welding.

Background technique

X80 pipeline steel is the highest-grade steel used in China's active pipelines. For long-distance oil and gas pipelines, welding is an indispensable process. At present, the main welding processes used in pipeline welding construction are: cellulose welding rod and self-protection agent The combined process of cored wire semi-automatic welding (SMAW+FCAW, commonly referred to as semi-automatic welding), argon-rich mixed gas shielded automatic welding process (GMAW, commonly referred to as automatic welding) and the combined process of cellulose electrodes and low-hydrogen electrodes (SMAW, Usually called manual welding); in these traditional welding processes, the pipeline steel undergoes a series of complex non-equilibrium physical and chemical processes during welding, resulting in uneven chemical composition and coarse grains in the weld and heat-affected zone , tissue segregation and other defects; in order to improve the quality of welded joints and improve the safety performance of welded joints in the pipeline service process, this patent proposes a new type of laser brazing welding method; laser brazing is a method that uses laser to melt welding wire Welding process, and then use the traction of the robot to infiltrate the molten welding wire into the parts to be welded, and finally fill the molten welding wire between the workpieces to be welded, thus completing the welding process, which is used to improve the technical defects caused by ordinary welding techniques. For large The laser brazing technology of steel is rarely used; the patent of this invention uses laser to preheat the base material and brazing material for pipeline steel to increase the bonding performance of the base material and brazing material, and then continue to use the laser beam to heat the brazing material to achieve the purpose of welding , to achieve the purpose of improving the performance of welded joints.

Contents of the invention

The invention is a welding method for long-distance oil pipelines, which uses laser to preheat materials, melts brazing material as the same heat source, avoids multiple processes, ensures uniform preheating effect in the preheating process, and solves the problem of no welding failure in the welding process. transparent problem.

The patent of the present invention uses a high-energy laser source as a unified preheating light source and welding light source, and uses reflectors, beam splitters, and focusing mirrors to perform steps on the laser including laser reflection, beam splitting, energy distribution, and refocusing to form two beams before and after. For the laser beam, the front laser beam is used as the preheating beam, and the rear laser beam is used as the welding beam. When using the preheating beam for preheating, a concave lens should be used to disperse the energy of the preheating beam.

As shown in Figure 1, the high-energy laser emitted by the laser is reflected by the mirror and irradiated on the beam splitter. The purpose of distributing the energy of the laser beam can be achieved by adjusting the position of the beam splitter, and the front and rear laser beams can be adjusted by adjusting the wedge angle of the beam splitter. spacing; the laser is reflected by the beam splitter and irradiated on the focusing mirror, and the laser will recombine into a laser beam with high energy density. The two laser beams are used for preheating and brazing heating respectively. The laser beam used for preheating is A concave lens is used to disperse the laser energy to both sides of the laser beam for uniform preheating. After the preheating is completed, the laser beam is directly brazed and welded to obtain good welding results. In order to determine the welding process parameters, the X80 pipeline steel material is first Try welding, try welding schematic diagram shown in Figure 2.

Description of drawings

Figure 1 Laser brazing system;

(1) laser; (2) mirror; (3) beam splitter; (4) concave lens; (5) focusing mirror; (6) workpiece;

Figure 2 Schematic diagram of trial welding;

Figure 3 Schematic diagram of X80 pipeline steel welded pipe;

Figure 4 Enlarged view of the weld;

Figure 5 Metallographic photograph of the weld.

Detailed ways

(1) Welding design: The cross-section of the pipeline steel weldment is shown in Figure 3. According to the thickness of the X80 pipeline steel and welding requirements, a V-shaped weld is used to fill the brazing filler metal. In order to ensure the welding, a hard brazing filler metal is used, and the material is silver-based brazing filler metal. The material and brazing flux are KBF4 type brazing flux, and the laser uses a carbon dioxide laser with a maximum power of 10kW; in order to determine the specific process parameters, a trial welding is carried out. The schematic diagram of the trial welding is shown in Figure 2. Adjust the wedge angle to zero, adjust the laser power output value, preheat at a speed of 1m/min, measure the inner wall temperature of the test welding sample through the thermal sensor on the inner wall of the pipeline steel, and make the inner wall temperature reach 400°C, with an upper and lower deviation of 10°C. The laser output power is about 2.5 kW, and the preheating power is determined; determine the power of the welding laser beam, and change the laser output power by adjusting the wedge angle and the position of the beam splitter to ensure that the preheating power is 2.5 kW, and the power fluctuation is ±50W; adjust Laser power and beam splitter position, finally determine the welding power to ensure a good welded joint is 3.75 kW, and the power fluctuation is ±50W; the mechanical properties of the test welding joint at this time are significantly improved compared with the conventional welding method; finally determine the laser beam splitting ratio 1: 1.5. By adjusting the beam splitter angle so that the beam spacing is 10mm and the spot diameters are 6mm and 4mm respectively, determine the welding process parameters.

(2) Cleaning before welding: Use organic liquid (acetone, alcohol, gasoline or trichlorethylene) or organic liquid vapor to clean the surface of the oily workpiece, and sandblast the oxidized surface to ensure good capillary tubes during welding. effect.

(3) Clamping: The clamping method of laser brazing is consistent with the conventional welding method; that is, the open steel pipe made by the three-roller symmetrical plate rolling machine is positioned with a V-shaped positioning structure, and the hydraulic mechanism is used to push the circle. The arc-shaped clamping device loads the steel pipe symmetrically, provides clamping force and fine-tunes the weld size.

(4) Filling brazing flux and brazing material: After clamping, apply KBF4 type brazing flux on the upper groove position of the base metal of the weld opening to increase the capillary force of the liquid brazing filler metal during brazing and enhance its spreadability , and then fill the opening of the pipeline steel weld seam with brazing filler metal, which is silver-based brazing paste.

(5) Laser heating. The welding process parameters are selected from the test welding result parameters, the preheating laser beam power is 2.5 kW, the welding beam power is 3.75 kW, the beam spacing is 10mm, the welding speed is 1m/min, the total output power of the laser is 6.25 kW, and the preheating laser beam is used for Preheat the brazing filler metal and the base metal at the junction with the brazing filler metal, and the subsequent laser is used to melt the solder and complete the welding. The weld seam after welding is shown in Figure 5.

(6) The tensile strength of the welded joint at room temperature is R _m =798MPa, exceeding the tensile strength R _m ≥ 625MPa required by the GB/T9711.2-1999 test standard, which can meet the requirements of the tensile test.

Claims (4)

1. The welding method of 1.X80 pipe line steel laser braze welding, it is characterized in that: utilize high energy laser sources as unified pre-thermal light source with weld light source, use speculum, spectroscope, focus lamp comprises laser reflection to laser, beam splitting, energy distribution, again interior step is focused on, the object of distributing laser beam energy is reached by adjusting spectroscopical position, the spacing of laser beam before and after the size adjustment at adjustment spectroscope wedge angle, two bundle laser beams before and after being formed, front laser beam is as preheating light beam, rear laser beam is as welding light beam, concavees lens should be used to carry out power dissipation to preheating light beam when using preheating light beam to carry out preheating,

   The power of described front laser beam should make X80 pipe line steel inner wall temperature reach 400 DEG C, upper lower deviation 10 DEG C;

   The power of described front laser beam is 2.5 kW, power swing ± 50W, and spot diameter is 6mm, carries out preheating with 1m/min speed;

   The power of described rear laser beam is 3.75 kW, power swing ± 50W, and spot diameter is 4mm, is 10mm with the beam separation of front laser beam, and speed of welding is 1m/min.
2. 2. the welding method of X80 pipe line steel laser braze welding as claimed in claim 1, is characterized in that: the weld seam of described X80 pipe line steel laser braze welding is V-shaped weld, and material is silver-base solder, and KBF selected by brazing flux ₄type brazing flux.
3. 3. the welding method of X80 pipe line steel laser braze welding as claimed in claim 1, is characterized in that comprising the steps:

   (1) welding design: according to X80 pipe line steel thickness and welding requirements, get V-shaped weld for filling solder, for ensureing that welding uses rigid solder, material is silver-base solder, KBF4 type brazing flux selected by brazing flux, and laser instrument uses carbon dioxide laser, and maximum use power is 10kW; For determining concrete technology parameter, carry out test weld, first test weld sample does pre-welding treatment, sets to zero in wedge angle, adjustment laser power output valve, carry out preheating with 1m/min speed, measure test weld sample inner wall temperature by the heat sensor at pipe line steel inwall place, make inner wall temperature reach 400 DEG C, upper lower deviation 10 DEG C, laser output power is 2.5 kW, power swing ± 50W, and warm-up power is determined; Determine to weld laser beam power, by adjustment wedge angle angle and spectroscope position, change laser output power, guarantee that warm-up power is 2.5 kW, power swing ± 50W; Adjustment laser power and spectroscope position, finally determine that the bonding power ensureing good welds joint is 3.75 kW, power swing ± 50W; The mechanical property measuring now test weld welding point requires tensile strength more than GB/T9711.2-1999 testing standard; Finally determine laser beam splitting ratio 1:1.5, make beam separation be 10mm by adjustment spectroscope angle, spot diameter is respectively 6mm and 4mm, determines welding condition;

   (2) cleaning before weldering: to there being the surface of the work of greasy dirt to use organic liquor or organic liquor steam cleans, blasting treatment being carried out to oxidized surface, having good capillarity when guaranteeing welding;

   (3) clamping: the installation way of laser braze welding is consistent with conventional soldering method; That is: the opening steel pipe made after three roller symmetric plate bending machine roller systems is used V-type location structure location, use hydraulic mechanism to promote circular arc clamping device and asymmetrical load is carried out to steel pipe, provide clamping force, and butt welded seam size is finely tuned;

   (4) fill brazing flux and solder: after clamping, on the mother metal of weld seam opening, groove position is coated with and spreads KBF ₄type brazing flux, for increasing the capillary force of liquid solder during soldering, strengthens its spreadability, then in pipeline weldmetal opening, fills up solder, and solder is money base pricker cream;

   (5) LASER HEATING: welding condition selects test weld result parameter, preheating laser beam power 2.5 kW, welding light beam power is 3.75 kW, beam separation is 10mm, preheating and speed of welding are 1m/min, and it is 6.25 kW that laser instrument exports general power, and preheating laser beam is used for preheating solder and the mother metal with solder joint, rear road laser, for melting solder, completes welding.
4. 4. the welding method of X80 pipe line steel laser braze welding as claimed in claim 3, is characterized in that: described organic liquor is acetone, alcohol, gasoline or trichloro-ethylene.