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Thick-walled 12Cr1MoVG pipe welding in low temperature environment


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c? Chan cR6v Correctional p0? v? _i Ai ? stir w5NH0_bT hail Hui production and application of section 38 (2) Osaka welding points [2] point of view 35. , The upper bevel angle 10. ,abercrombie danmark, Blunt edge thickness 1.5 ~ 0.5mm, 2.1 '/ g ~-r: Elg-point gap analysis of their counterparts in Division I for the 2 ± O · 5mm. Ambient temperature according to the particular site conditions, re-welding process (2) TIG rendering, rod arc welding layer and cover point should be the first to preheat temperature and interpass temperature control allows the surface; the wire is H08CrMoVA, welding rod for the E5515 a B2V. Range, avoid cracks in welding temperature, to prevent welding (3) preheating temperature 200 ℃ ~ 300 ℃; layer temperature of 250 ℃ then cracks occur. ~ 350 ℃. Welding points are as follows: (4) Welding specification parameters shown in Table 3. (1) groove type: single-sided double V-groove, the lower groove (5) post-weld heat treatment temperature: 750 ℃, heat 3h, slow cooling or welding specifications in Table 3 Parameters 2AWE5515 a B2V rest AWE5515 a B2V3. 24. O DC DC 90 ~ 130l2O ~ l6o24-30243O temperature and cooling rate of speed does not exceed 130 ℃ / h. 2.2 Construction of technological measures taken f1) seam welding operation must be in place before the erection of wind insulation shed, shed heat setting electric heating to ensure that the greenhouse temperature greater than or equal O ℃. f2) block both ends of the nozzle, pipe slow cooling rate. The flow of cold air in the pipeline will speed up the cooling rate after heat pipes, affecting the quality of welding. The use of nozzle blocking method can effectively reduce the cooling rate, extend the pipe weld cooling time between layers to ensure that the temperature within prescribed limits. f31 allows the assessment of welding preheat temperature range,franklin and marshall, the preheating temperature increased as much as possible to ensure that the welding process are at the required temperature range, the range to warm up their counterparts in the centerline as the base,ed hardy danmark, each side is not less than 150mm, heating 100mm outside the area within the insulation. Leave after the warm-up welding position, the weld on both sides of 100mm range with asbestos insulation cotton wrap. (4) 12CrlMoVG significantly hardening tendency, thus requiring the use of groove machining process as much as possible, if the flame cut, rubbed off the hardened layer after cutting to avoid cutting the surface of hardened and cracks. To ensure that the weld diffusible hydrogen content to a minimum, to the edge and outside surface of the groove and 20mm wide oil,fitch abercrombie, paint, rust, dirt, etc. thoroughly cleaned. f5) hardened steel to reduce the tendency to slow down the weld cooling rate, in order to facilitate improvement of hydrogen spillover and stress conditions,tory burch uk, thereby reducing the tendency to delayed cracking joints,ralph lauren danmark, should be strictly controlled preheat temperature, ambient temperature conditions at the scene, positioning welding formal welding preheat temperature and preheat temperature are warm-temperature welding procedure to take the upper limit. f6) while using two welders welding, continuous welding of the principles to effectively reduce the cooling rate,ed hardy tøj, the welding temperature as much as possible at a suitable temperature range to ensure the stability of the welding process. (7) welding is completed immediately covered with insulating cotton welded joints, slow cooling weld diffusible hydrogen in a timely manner conducive to overflow, reducing the hardening tendency. 3 welding effect on 20 January 2006 to 200r7 1O January 12, Ordos in Inner Mongolia Shenhua coal direct liquefaction project on the high pressure steam pipe wall thickness of 50mm 12Cr1M0VG welding,ed hardy uk, welding using the above method a total of 198 welds, the results as follows: (1) 100% of the weld-ray detection, 100% magnetic particle inspection after cracks found defects. (2) To further ensure the level of detection of welding defects, according to the sensitivity of ultrasonic flaw detection on crack characteristics of a high, an increase of 100% ultrasonic inspection and found no cracks defects. (3) After the heat treatment of the weld after weld hardness, HB 270 or less are in line with 4 Conclusion The process by taking reasonable measures to ensure the quality of thick-walled 12Cr1M0VG pipe welding in the construction process of accumulating a greater tendency hardened steel low temperature welding experience for similar future pipeline construction to create the conditions for welding. References: [1] Zhou Zhenfeng. Principles and processes which metal welding. Beijing: Mechanical Industry Press, 1988. [2] Jia-Zhen. Pressure vessel materials,abercrombie paris, carbon steel and alloy steel manual eleven [M]. Beijing: Chemical Industry, Press,ed hardy sverige, 20o0.0Otll a 55

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