Clean the groove and base metal within 25mm on both sides with stainless steel wire brush.
5.2} before repair, the defect nature, length and width shall be analyzed to confirm the defect location.
2.1.3 before the welding wire is used, the grease and other sundries on the surface must be removed with acetone or alcohol.
It is strictly prohibited to use chlorinated hydrocarbons such as carbon tetrachloride as degreasing solvent.
3.5 all parts of auxiliary tooling in contact with base metal shall be zirconium or austenitic stainless steel.
2) Full penetration welding shall be adopted for all nozzle welds.
3.7.7 the interlayer temperature shall be strictly controlled, and the interlayer temperature shall not be greater than 107 ° C.
2.2.3 the welder shall have complete flashlight, endoscope, staggered detector and contact thermometer.
2.1.2 the welding wire used must have quality certificate or material certificate.
6.3 after welding, NDT shall be carried out as required..
4.2 the purity of argon must be checked after each replacement of argon cylinder or gas belt.
The length of the pipeline is long, and local argon filling is adopted.
4.3) shall be used during welding to ensure that the whole weld area is well protected in solid and molten state until room temperature.
3.1 welding construction procedure: 3.2 groove requirements: 3.2.1 groove size 3.2.2 quality requirements during assembly: the inner wall shall be flush and the staggered joint shall not exceed 0.5mm3 2.3} before assembly, clean the groove and oil stains and other sundries within 75mm on both sides with acetone or alcohol.
6.2 the weld surface shall be free of cracks, incomplete fusion, pores, slag inclusion and other impurities.
2.
3.4 spot welding: the spot welding method is bridge welding, the process and welding materials are the same as the formal welding process, and the number of welding points is 3 ~ 4.
5.4 the welding process of repair shall be the same as that of formal welding.
General construction process for zirconium and zirconium alloy welding of industrial pipeline 1 scope of application this process is applicable to the welding construction of zirconium and zirconium alloy pipes by all argon arc welding in the project.
2.1.4 the purity of argon used must be ≥ 99.999%.
2.2.2 the welding wire barrel, planer hammer (surface surfacing stainless steel layer), stainless steel wire brush and file used by the welder shall be complete, the tools must be special, and degreasing cleaning shall be carried out regularly.
4.3 tail protection device (Fig.
5 weld repair 5.1 weld repair task shall be undertaken by welders with certificates and corresponding qualified items.
2) If it is installed on site, regardless of the environment (wind, rain and snow), a wind shelter must be erected.
3.3 welding method: 1) all welded junctions shall be welded by full argon arc welding.
3.7.5 the tungsten electrode adopts 2% thorium tungsten electrode.
2.2.4 cooling fan (if conditions are available on site, it can be cooled by device air).
The argon filling time is 5 ~ 10 times that of stainless steel welding.
3.7.6 grinding machine shall be avoided as far as possible, and metal grinding head can be used for grinding.
The construction site shall be equipped with fixed welding material warehouse or mobile welding material warehouse meeting the requirements.
5.5 the management level of weld repair shall comply with the provisions in the pressure pipeline quality assurance manual.
If the length of fixed port pipeline is short, integral argon filling shall be adopted.
4.34.4 high frequency arc striking is adopted during welding, and friction arc striking is not allowed.
4) The welding machine shall not be more than 5m away from the weldment.
4 welding precautions and requirements 4.1 the gas belt for argon must be kept dry to ensure the purity of argon.
3.7.9 after welding, the trailing cover can be removed after cooling to room temperature, and then the welder’s steel seal, pipe line number and welding slogan shall be marked with a marking pen 50mm away from the weld.
The argon filled structure is shown in figure 3.7.3: 3.7.4 during welding, pay attention that the end of the welding wire shall not leave the argon protection area.
Construction preparation 2.1.
5.3 defect removal method: use metal grinding head or grinder for grinding, and repair the groove of the repaired part.
It must be used up within 30 minutes after cleaning, otherwise it shall be cleaned again before use.
2.3.2 environmental conditions: confirm that the environment meets the following conditions before welding: 1) prefabrication in indoor prefabrication plant is preferred.
3.6 welding process (see attached table) 3.7 welding key points: 3.7.1 arc striking adopts back welding method; 3.7.2 the method of small current and slight swing shall be adopted during welding; 3.7.3 when the back is filled with argon for protection, both ends of the prefabricated opening pipe can be blocked with sponge.
3.7.8 socket weld shall be formed at least twice.
If the welding wire is taken out of the argon, the end of the welding wire shall be cut off at least 25mm when continuing welding.
Fig.
The welded junction shall be sealed with high temperature resistant adhesive paper (medical rubber is not allowed), and the open length shall be the length of one-time welding seam.
6.1 quality standard 6.1 the weld appearance shall be well formed, the appearance shall be smooth and excessive, the weld width shall cover the groove edge by 2mm, and the base metal of the weld shall not be lower than the surface of the base metal.
3) If the ambient temperature is lower than 15 ℃, it must be preheated above 15 ℃ before welding.
Material requirements: 2.1.1.
2.2 equipment requirements: 2.2.1 the welding machine is a special argon arc welding machine with high-frequency arc striking device, and is equipped with remote control current device and water cooler.
If grinding machine is used for grinding.
The grinding shall be watered and cooled at the same time, and the grinding temperature shall not exceed 315 ° C to avoid strong oxidation.
2.3 operation conditions: 2.3.1 personnel qualification: the welder must hold asme1x certificate and the position shall meet the welding requirements.
4.5 after welding, hammering is not allowed.
