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CN-121972771-A - Full-position argon arc welding method for semiconductor grade ultra-high purity stainless steel pipeline

CN121972771ACN 121972771 ACN121972771 ACN 121972771ACN-121972771-A

Abstract

The invention discloses an all-position argon arc welding method for a semiconductor grade ultra-high purity stainless steel pipeline, which relates to the technical field of welding of the semiconductor grade ultra-high purity stainless steel pipeline, and comprises the steps of firstly carrying out ultra-high cleanliness pretreatment on the pipe end of the pipeline to be welded to finish groove forming and oxide film removal, finishing pipeline coaxiality assembly in a clean environment, building a double-layer high purity argon laminar flow protection system inside and outside the pipeline, constructing a partition welding parameter matrix based on all-position welding stations, adopting low heat input pulse argon tungsten arc welding to finish continuous welding of a pipeline girth, dynamically trimming welding parameters in the whole welding process, and carrying out in-situ passivation treatment on welding seams and the inner wall of the pipeline after welding. The invention can realize the uniform forming of all-position welding of the semiconductor grade ultra-high purity stainless steel pipeline, effectively control the risks of oxidation and forming defects of the welding line and intergranular corrosion, ensure the cleanliness of the inner wall of the pipeline and the corrosion resistance of the welding line, and adapt to the severe use requirements of the transportation of the semiconductor ultra-high purity medium.

Inventors

  • CHEN KAIKAI

Assignees

  • 上海帛亨机电设备安装工程有限公司

Dates

Publication Date
20260505
Application Date
20260402

Claims (10)

  1. 1. The full-position argon arc welding method for the semiconductor-grade ultra-high-purity stainless steel pipeline is characterized by comprising the following steps of: Carrying out ultra-high cleanliness pretreatment on the pipe end of a semiconductor-grade ultra-high purity stainless steel pipeline to be welded, sequentially finishing the end face flat processing, the electrolytic polishing of the inner wall, degreasing and decontaminating, the flushing of ultrapure water, dust-free drying, synchronously finishing the precise forming of a welding groove and the removal of an oxide film on the surface of the groove, and controlling the inner wall roughness and cleanliness core indexes of the pipe end; The method comprises the steps of finishing high-precision assembly of a pipeline to be welded and pre-welding system protection, finishing coaxiality assembly of the pipeline in a thousand-level clean environment, controlling assembly gaps and misalignment amount, synchronously constructing a double-layer high-purity argon laminar flow protection system on the inner wall and the outer wall of the pipeline, finishing oxygen content replacement and airtight pressure maintaining in the pipeline before welding, and ensuring that the oxygen content in the pipeline is lower than a preset safety threshold in the whole welding process; Based on four welding stations of horizontal welding, vertical upward welding, overhead welding and vertical downward welding of pipeline all-position welding, an all-position partition welding parameter matrix is constructed, matching parameters of welding pulse current basic values and peak values, pulse frequency, wire feeding speed, welding travelling speed and internal and external protection argon flow are respectively set for different stations, and meanwhile, parameter smooth transition intervals among the stations are set; Performing full-position continuous welding by adopting a low-heat input pulse argon tungsten-arc welding process, completing one-time continuous welding of a pipeline circumferential seam according to a preset partition parameter matrix, monitoring the temperature of a molten pool, the forming state of a welding seam and the purity of shielding gas in real time in the whole welding process, performing closed-loop dynamic fine adjustment on welding parameters based on monitoring data, and controlling the heat affected zone range of the welding seam and the energy input of the welding line; And after the welding is finished, carrying out in-situ passivation treatment on the welding line and the inner wall of the pipeline, adopting high-purity nitrogen atomized electronic grade passivation solution to complete uniform passivation of the welding line area, and synchronously completing circulating flushing and dust-free drying of the passivated ultrapure water to form a uniform and compact corrosion-resistant passivation film on the surface of the welding line.
  2. 2. The full-position argon arc welding method of the semiconductor grade ultra-high purity stainless steel pipeline according to claim 1, further comprising the step of full-position welding line energy precise control, wherein in the welding parameter matrix construction process, welding line energy calculation formulas are introduced for different welding stations, and welding heat input of each station is precisely quantified and controlled, wherein the calculation formulas are as follows: ; Wherein the method comprises the steps of To correspond to the weld line energy of the welding station, Is the thermal efficiency coefficient of argon tungsten-arc welding, For the welding arc voltage to be sufficient, For an effective value of the welding current, Is the weld travel speed.
  3. 3. The all-position argon arc welding method for the semiconductor grade ultra-high purity stainless steel pipeline according to claim 1, further comprising a step of dynamically regulating and controlling the laminar flow protection of the high purity argon in the pipeline, wherein the flow and the pressure of the argon for protecting the inner wall of the pipeline are dynamically regulated in the whole welding process according to the real-time change of a welding station, the static pressure of the argon in the lifting pipe of the overhead welding station is used for counteracting the gravity falling influence of a molten pool, and the stable laminar flow state is maintained at the overhead welding station to isolate the invasion of external air.
  4. 4. The full-position argon arc welding method for the semiconductor grade ultra-high purity stainless steel pipeline according to claim 1, further comprising a step of classifying and controlling the cleanliness before welding, wherein corresponding pretreatment cleanliness grades are set for the semiconductor grade ultra-high purity stainless steel pipelines with different specifications and different application scenes, and the oil residue, the number of particle pollutants and the surface roughness core index of the inner wall of the pipeline are respectively controlled, and sealing protection of the pipeline port is completed in hundred-grade clean environment after pretreatment is completed.
  5. 5. The full-position argon arc welding method for the semiconductor grade ultra-high purity stainless steel pipeline according to claim 1, wherein in the pipeline pairing step, the coaxiality misalignment amount of the pipeline to be welded is controlled to be within 5% of the wall thickness of the pipeline, pairing gaps are controlled to be between 0.5mm and 2mm, and after pairing is finished, temporary fixation is finished by adopting a stainless steel positioning clamp with standard cleanliness, and positioning welding spots are arranged on the outer wall of the pipeline and are completely in the groove range of subsequent welding.
  6. 6. The full-position argon arc welding method for the semiconductor grade ultra-high purity stainless steel pipeline according to claim 1, wherein in the double-layer high purity argon laminar flow protection system, a welding gun nozzle with a gas lens structure is adopted for outer wall protection, uniform and stable sending out of argon is realized through a laminar flow rectification structure, a double-side adjustable gas plug structure is adopted for inner wall protection, a sealed protection air cavity is formed in the pipelines at two sides of a welding line, air replacement in the air cavity is completed by continuously introducing high purity argon before welding, and oxygen content in the air cavity is continuously monitored in the whole welding process.
  7. 7. The all-position argon arc welding method for the semiconductor grade ultra-high purity stainless steel pipeline according to claim 1, wherein in the in-situ passivation treatment step, a passivation film uniformity evaluation calculation formula is introduced for the passivation effect of a welding line area, closed-loop optimization adjustment is carried out on passivation treatment process parameters, and the calculation formula is as follows: ; Wherein the method comprises the steps of Is the uniformity coefficient of the passivation film in the weld area, To passivate the total number of film thickness detection points, Is the first The passivation film measured thickness of each detection point, The arithmetic average of passivation film thickness at all detection points is given.
  8. 8. The all-position argon arc welding method for the semiconductor grade ultra-high purity stainless steel pipeline according to claim 1, wherein in the all-position welding parameter matrix, the welding peak current of a flat welding station is set to be 80-120A, the welding peak current of a vertical welding station is set to be 100-140A, the welding peak current of a overhead welding station is set to be 70-100A, the welding peak current of a vertical welding station is set to be 90-130A, the pulse frequency of each station is set to be 30-80 Hz, the basic value current is 30-40% of the peak current, a parameter transition interval of 10-15 DEG is set between adjacent stations, and an intra-interval welding parameter adopts a linear smooth adjustment mode.
  9. 9. The full-position argon arc welding method for the semiconductor grade ultra-high purity stainless steel pipeline according to claim 1, wherein in the pre-welding pipe end pretreatment step, the inner wall of the pipe end is treated by adopting a precise electrolytic polishing process, degreasing and decontamination are carried out by adopting electronic grade absolute ethyl alcohol for ultrasonic cleaning, the ultrasonic cleaning time is not less than 15 minutes, ultrapure water is adopted for circulating flushing, high-purity nitrogen with hundred grade cleanliness is adopted for constant-temperature dust-free drying after flushing, and a clean dust-proof plug is adopted for double-sealing protection of the pipe end immediately after drying is finished.
  10. 10. The full-position argon arc welding method for the semiconductor grade ultra-high purity stainless steel pipeline according to claim 1, further comprising carrying out nondestructive testing and cleanliness and corrosion resistance system verification on welded seams of the pipelines, sequentially completing nondestructive testing of welding seams, inner wall roughness testing, granularity testing and intergranular corrosion testing, wherein the nondestructive testing of the rays needs to meet the I-level welding requirements in the section of nondestructive testing 2 of NB/T47013.2, namely radial testing of pressure equipment, the granularity testing of the inner wall needs that the quantity of solid particles in the pipeline is more than 0.1 mu m and does not exceed the limit value specified by SEMI F72 standard, the intergranular corrosion testing is carried out by an oxalic acid etching method in the intergranular corrosion testing method of metal and alloy, ferrite-austenite (duplex) stainless steel, and after the testing, the welding seams and a heat zone have no intergranular corrosion groove and crack defects, and simultaneously carrying out oxidation color inspection on the inner wall of the welding seams.

Description

Full-position argon arc welding method for semiconductor grade ultra-high purity stainless steel pipeline Technical Field The invention relates to the technical field of welding of semiconductor-grade ultra-high-purity stainless steel pipelines, in particular to an all-position argon arc welding method of a semiconductor-grade ultra-high-purity stainless steel pipeline. Background In the manufacturing process of semiconductor chips, stable transportation of mediums such as ultra-high purity special gas, ultra-high purity water, chemical reagents and the like is a core link for guaranteeing the production yield and the process stability of the chips, and the quality of a welded joint of the semiconductor grade ultra-high purity stainless steel pipeline serving as a core transportation carrier of the mediums directly determines the cleanliness, corrosion resistance and long-term operation stability of a medium transportation system. The full-position argon arc welding is the most widely applied girth welding process in the field installation construction of a semiconductor pipeline, the girth welding of the pipeline needs to be continuously covered with flat welding, vertical upward welding, overhead welding and vertical downward welding at a plurality of different stations, the process parameters of the welding process are controlled, the cleanliness is controlled and the welding seam is protected, the forming quality, the inner wall cleanliness and the intergranular corrosion resistance of the welding seam are directly determined, the requirements of the semiconductor industry on the welding seam are met, the conventional mechanical performance index is met, the strict requirements of the oxidation degree, the surface roughness, the particle pollutant residue and the corrosion resistance of the inner wall of the welding seam are far higher than those of the conventional industrial pipeline, and the higher standard is also provided for the full-position welding process control of the pipeline. The existing all-position argon arc welding process system is mainly designed for welding stainless steel pipelines in the conventional industrial field, a full-flow cleanliness management and control system is not established according to the use requirement of semiconductor-grade ultra-high-purity pipelines, the process standard of pre-welding pipe end pretreatment is not clear, the process steps of inner wall polishing, degreasing, decontaminating, washing and drying are lack of targeted management and control, pollutants such as grease, metal fragments, solid particles and the like are easily introduced into the pipelines before welding is implemented, and the cleanliness of the pipelines after welding cannot meet the use standard of the semiconductor industry. Meanwhile, the existing all-position welding process mostly adopts uniform welding parameters to finish full-circle girth welding, does not carry out differentiated parameter design aiming at the stress state and the molding characteristics of a molten pool of different welding stations, is easy to generate defects of uneven weld joint molding, incomplete penetration, weld flash, undercut and the like in the all-position welding process, and is easy to cause coarse grains of a weld joint and a heat affected zone due to lack of accurate quantitative control on welding heat input, thereby greatly improving the intergranular corrosion risk in the use process of the weld joint and being incapable of adapting to the use requirement of long-term stable conveying of ultra-high purity media by a semiconductor pipeline. The existing welding line protection system of the welding process only focuses on the outer wall gas protection in the welding process, the pipeline inner wall protection adopts a constant argon-introducing mode with fixed flow, the dynamic regulation and control of the protection gas flow and the pressure cannot be carried out according to the real-time change of the welding station, the problems of the laminar state damage of the protection gas and the invasion of the external air are easy to occur in the overhead welding station and the vertical welding station, the defects of oxidation discoloration, oxidation inclusion and the like of the inner wall of the welding line are caused, and the cleanliness and the corrosion resistance of the inner wall of the welding line are directly damaged. Meanwhile, in the prior art, the post-welding passivation treatment mostly adopts an integral off-line pipeline passivation mode, the accurate in-situ passivation treatment cannot be carried out on a welding line area, the problems of uneven passivation film thickness and insufficient compactness of the welding line area are easy to occur, the corrosion resistance of the welding line area is obviously different from that of a pipeline parent metal, the problems of preferential corrosion and particle shedding of the welding line area are easy to occur in the proc