阅读说明：本技术 一种用于空调压缩机壳体直缝焊接的方法 (Method for straight seam welding of air conditioner compressor shell ) 是由 彭扬文 于 2018-06-29 设计创作，主要内容包括：本发明公开了一种用于空调压缩机壳体直缝焊接的方法,主要解决现有空调压缩机壳体的焊接直缝发生开裂和焊接接头存在气孔、咬边、未焊透、焊瘤等焊接质量问题。本发明提供的一种用于空调压缩机壳体直缝焊接的方法,包括：1)清理钢板待焊表面；2)制备空调压缩机壳体毛坯；3)对空调压缩机壳体毛坯进行焊接加工,将卷圆后的钢板的对接直缝进行焊接,采用等离子焊接工艺,电弧中心正对对接直缝的中心,控制焊枪沿焊缝中心进行移动焊接,焊接时焊枪与焊接前进水平方向的倾角为80～85度,焊接过程中焊缝正面采用气体保护,保护气体为Ar气,气体纯度为99.99％。本发明方法焊接效率高,焊接质量好,操作简便,焊接成本低。(The invention discloses a method for welding straight seams of an air conditioner compressor shell, which mainly solves the problems of cracking of the welding straight seams of the existing air conditioner compressor shell and the welding quality of air holes, undercut, incomplete penetration, welding beading and the like of a welding joint. The invention provides a method for straight seam welding of an air conditioner compressor shell, which comprises the following steps: 1) cleaning the surface to be welded of the steel plate; 2) preparing a shell blank of the air conditioner compressor; 3) welding a shell blank of the air conditioner compressor, welding a butt straight seam of a rolled steel plate, adopting a plasma welding process, enabling an electric arc center to be over against the center of the butt straight seam, controlling a welding gun to perform movable welding along the center of a welding seam, enabling an inclination angle of the welding gun and the horizontal direction of welding progress to be 80-85 degrees during welding, adopting gas protection on the front side of the welding seam during welding, wherein protective gas is Ar gas, and the gas purity is 99.99%. The method has the advantages of high welding efficiency, good welding quality, simple and convenient operation and low welding cost.)

1. A method for straight seam welding of an air conditioner compressor shell is characterized by comprising the following steps:

1) cleaning the surface to be welded of the steel plate, removing burrs at a notch of the steel plate for the acid pickling air conditioner compressor with the thickness of 2.75-4.0 mm, and cleaning the surface to be welded of the steel plate by using acetone;

2) preparing a shell blank of the air condition compressor, rolling the steel plate and then butting the steel plate, wherein the butting gap is 0, and the misalignment in the thickness direction of the steel plate at the butting position is less than or equal to 0.2 mm;

3) welding a shell blank of the air conditioner compressor, welding a butt straight seam of a rolled steel plate, adopting a plasma welding process, enabling an arc center to be opposite to the center of the butt straight seam, controlling a welding gun to perform movable welding along the center of a welding seam, enabling an inclination angle of the welding gun and the horizontal direction of welding advance to be 80-85 degrees during welding, adopting gas protection on the front side of the welding seam during welding, wherein Ar is protective gas, the gas purity is 99.99%, and the flow of the protective gas is 18-20L/min.

2. The method for straight seam welding of the shell of the air conditioner compressor as claimed in claim 1, wherein in the step 3), the plasma gas in the welding process is Ar gas, the gas purity is 99.99%, and the ion gas flow is 2.0-2.4L/min.

3. The method for straight seam welding of the shell of the air conditioner compressor as claimed in claim 1, wherein in the step 3), the welding process adopts gas shielding on the back of the welding seam, the welding shielding gas is Ar gas, the gas purity is 99.99%, and the flow rate of the shielding gas is 20-30L/min.

4. The method for straight seam welding of the shell of the air conditioner compressor as claimed in claim 1, wherein the welding process in the step 3) adopts external water cooling to cool the fixture.

Technical Field

The invention relates to a welding processing method of a compressor shell, in particular to a method for straight seam welding of an air conditioner compressor shell, and belongs to the technical field of steel material welding processing.

Background

The shell of the air conditioner compressor is usually made of a hot-rolled pickled steel plate as a base plate, the thickness of the steel plate is 2.75-4.0 mm, the grades produced by Baoshan Steel works Limited are SPHC, SPHD and SS400, the C content of the SPHC is 0.04-0.065%, the yield strength is 186-349 MPa, the C content of the SPHD is 0.03-0.054%, the yield strength is 180-280 MPa, the C content of the SS400 is 0.125-0.165%, the yield strength is 250-350 MPa, the steel plate is rolled and then plasma straight seam welding is carried out, and then the subsequent air conditioner compressor assembling process is continuously completed. The existing client air conditioner compressor shell welding mainly adopts two modes, one mode is a single-piece mode, namely, each steel plate processed according to the specified size needs to be subjected to edge rolling, arc starting and arc closing so as to finish the welding process; and the other type is a tube-making type, namely the steel coil is uncoiled after being stripped, the coiling process is completed through different roller systems, and the welding gun is continuously welded after being subjected to arc starting. In the existing plasma welding process, only protective gas is introduced into the front side of a welding seam, the back side of the welding seam is not protected, and the angle of a welding gun is perpendicular to a steel plate for welding, namely the inclination angle of the welding gun is 0 degree.

The welding joint is a weak link of the shell of the air conditioner compressor, and most air leakage of the air conditioner compressor occurs at the welding joint, and the main reason is that the welding joint has defects of undercut, incomplete penetration, air holes and the like locally, so that the shell of the air conditioner compressor is cracked and leaks air at the welding joint in the use process. According to the existing welding process for the shell of the air conditioner compressor, the front side of a welding line is undercut, the back side of the welding line is not uniformly formed, and even welding beading and incomplete penetration occur.

Disclosure of Invention

The invention aims to provide a method for welding straight seams of an air conditioner compressor shell, which mainly solves the problems of cracking of the welding straight seams of the existing air conditioner compressor shell and the welding quality of air holes, undercut, incomplete penetration, welding beading and the like of a welding joint.

The invention adopts the technical scheme that the method for the plasma straight seam welding of the shell of the air conditioner compressor comprises the following steps:

1) cleaning the surface to be welded of the steel plate, removing burrs at a notch of the steel plate for the acid pickling air conditioner compressor with the thickness of 2.75-4.0 mm, and cleaning the surface to be welded of the steel plate by using acetone;

2) preparing a shell blank of the air condition compressor, rolling the steel plate and then butting the steel plate, wherein the butting gap is 0, and the misalignment in the thickness direction of the steel plate at the butting position is less than or equal to 0.2 mm;

3) welding a shell blank of the air conditioner compressor, welding a butt straight seam of a rolled steel plate, adopting a plasma welding process, enabling an arc center to be opposite to the center of the butt straight seam, controlling a welding gun to perform movable welding along the center of a welding seam, enabling an inclination angle of the welding gun and the horizontal direction of welding advance to be 80-85 degrees during welding, adopting gas protection on the front side of the welding seam during welding, wherein Ar is protective gas, the gas purity is 99.99%, and the flow of the protective gas is 18-20L/min.

Further, in the step 3), the plasma gas in the welding process is Ar gas, the gas purity is 99.99%, and the ion gas flow is 2.0-2.4L/min.

Further, the back of the welding seam in the welding process in the step 3) is protected by gas, so that the back welding seam can be effectively prevented from being oxidized, the welding seam is formed, and the welding seam quality is improved; the welding protective gas is Ar gas, the gas purity is 99.99%, and the protective gas flow is 20-30L/min.

Further, in the step 3), the welding gun is cooled by circulating cooling water, and the clamp is cooled by adopting an external water cooling mode.

Further, the inclination angle of the welding gun and the horizontal direction of welding advance in the step 3) is 80-85 degrees, and the too large or too small inclination angle is not beneficial to fully stirring the molten pool, so that uniform welding seams cannot be obtained.

The invention uses plasma welding technique, the welding gun has a certain inclination angle, and the back of the welding plate is added with protective gas. The invention is small-hole plasma welding, the plasma flame blows the melted metal to the other side of the welding seam to form a hole (small hole), the welding speed must be kept uniform, and the welding pool can slowly solidify and move forward along with the plasma arc. The welding process is characterized in that the electric arc is mechanically compressed by a water-cooled central nozzle, so that a heat affected zone is narrower, energy is more concentrated, and the utilization rate is higher.

The invention utilizes the influence of the inclination angle of the welding gun on the formation of the welding bead, when the welding gun is inclined forwards, the arc blowing force pushes the molten pool backwards, and the heat of the arc is concentrated on the unmelted base metal, thereby forming the welding bead with deep penetration and narrow melting width. Under the condition that the welding speed is kept unchanged, the inclination angle of the welding gun is changed within a certain range, so that a molten pool can generate good oscillation, and in addition, the heat of an electric arc is concentrated on unmelted base metal, so that the cooling time of a welding seam is delayed. In the invention, because the inclination angle of the welding gun is changed, the heat of the electric arc is concentrated on the unmelted base metal behind the welding gun, and the welding process can be finished by steel plates with the same thickness only by smaller heat input.

The invention also carries out gas protection on the back of the welding seam, and the protective gas adopts argon with the purity of 99.99 percent, the argon is taken as the protective gas, the arc striking is more stable during welding, the arc is stable and soft, the density of the argon is high, a good protective cover is easy to form, and a better protective effect is obtained. The back is added with gas protection during welding, so that molten pool metal is not easily oxidized, complete and uniform welding seams are easily formed, welding defects such as incomplete penetration, welding beading and the like are avoided, and good welding seam forming is favorably ensured. In the welding process, the welding current is 160-170A, the arc voltage is 21-23V, and the welding speed is 360-540 mm/min.

Compared with the prior art, the invention has the following positive effects: 1. the method of the invention adjusts the angle of the plasma welding gun, the welding gun leans forward in the welding advancing direction when the shell of the air conditioner compressor is subjected to plasma welding, the arc blowing force pushes the molten pool backwards, the heat of the arc is concentrated on the unmelted base metal, thus forming a weld bead with deep penetration and narrow penetration width, ensuring full penetration of the weld joint under low heat input and having small heat affected zone. The mechanical property of the welding joint is improved, the low heat input enables the crystal grains of the welding joint to be finer, and the bearing capacity of the welding joint of the shell of the air conditioner compressor is improved. 2. The method of the invention can ensure that the metal of the molten pool is not easily oxidized by increasing the back protection when the shell of the air conditioner compressor is welded, and the defects of incomplete penetration, welding beading and the like can not be generated, thereby being beneficial to ensuring good formation of the welding seam. Through measurement, the width of a front welding line is 5-6 mm, the width of a back welding line is 2.0-2.5 mm, nondestructive flaw detection is carried out on the welding line, the qualification rate reaches 99%, and no bubble is generated in a hydraulic test. 3. The method has the advantages of high welding efficiency, good welding quality, simple and convenient operation and low welding cost; in the prior art, under the condition of the same steel plate thickness, the welding current adopted at the same welding speed is 170-180A, the arc voltage is 23-24V, and the welding cost is high.

Detailed Description

The present invention is further illustrated below with reference to examples 1 to 3, as shown in Table 1.

In the embodiment of the invention, the hot-rolled pickled steel plate with the mark of SPHC, which is produced by Baoshan iron and steel products Co., Ltd, is adopted to manufacture the shell of the air-conditioning compressor, the thickness is 3.0mm, the C content is 0.055%, and the yield strength is 269 MPa.