压力容器的焊接技术条件

1、Welding of Steel Pressure VesselsOrig.:Checked:Appr.:Total 6 PagesIssue 06.2003Descriptors: Pressure Vessel, Welding, SteelReplaces Issue03.99ContentPage TOC o 1-5 h z HYPERLINK l bookmark0 o Current Document 1Scope1 HYPERLINK l bookmark2 o Current Document 2Manufacturing Requirements1Quality Manage

2、ment System1SubcontractingWelders and Welding ProceduresFiller Materials and Auxiliary MaterialsManufacturing FacilitiesTesting Facilities and Test PersonnelMarking SystemsDesign and Form TOC o 1-5 h z HYPERLINK l bookmark18 o Current Document General3 HYPERLINK l bookmark20 o Current Document Welds

3、 in Pressure-Bearing Walls3 HYPERLINK l bookmark22 o Current Document Attachments3 HYPERLINK l bookmark24 o Current Document Manufacturing and Testing3 HYPERLINK l bookmark26 o Current Document General3 HYPERLINK l bookmark28 o Current Document Weld Bevel Preparation4 HYPERLINK l bookmark30 o Curren

4、t Document Preheating4 HYPERLINK l bookmark32 o Current Document Tack Welds4 HYPERLINK l bookmark34 o Current Document Temporary Attachment Welds4 HYPERLINK l bookmark36 o Current Document Weld Repairs4 HYPERLINK l bookmark38 o Current Document Weld - and Component Surfaces4 HYPERLINK l bookmark40 o

5、 Current Document Production Weld Test Plates4Time of TestPostweld Heat Treatment. Material-specific RequirementsC- and C-Mn-SteelsHigh-Temperature Cr-Mo-SteelsNi-Steels for Low Temperature ServiceAustenitic CrNi-SteelsDuplex SteelsScopeThis standard shall apply to the welding of steel pressure vess

6、els. It is intended for manufacturers of pressure vessels and shall apply in addition to the code requirements specified for the particular order.Statements made in the vessel datasheets and in the specifications for testing and inspection shall have priority over the requirements of this standard.M

7、anufacturing RequirementsQuality Management SystemThe contractor shall have an appropriate quality management system, e.g.:in accordance with ISO 9001,9002, 9003 orcompliance with the requirements of EN 729-2 as a minimum ormanufacturer is ASME U-Stamp holderLINDE reserves the right to audit the imp

8、lementation of the quality requirements.Page 2Issue 06.2003SubcontractingThe subcontracting of welding and heat treatment work and nondestructive testing of welds shall be permitted with the written approval of the Purchaser only. The manufacturer shall ensure that his subcontractors are fully infor

9、med of Purchasers requirements; he shall convince himself of the compliance with these requirements, including the observance of the requirements of the present standard.Welders and Welding ProceduresThe welders and welding procedures to be employed for the work shall be qualified in accordance with

10、 the specified code. This applies also to repair welds. The Purchaser reserves the right to review the relevant qualifications.Filler Materials and Auxiliary MaterialsFor their intended scope of application the filler materials shall be qualification-tested and/or approved by the manufacturer of fil

11、ler materials acc. to the specified code, i.e. in general base metal matching fillers with reference to strength, toughness and corrosion resistance, unless base metal deviating properties (Re, Rp, creep rupture strength) have been considered for vessel design/calculation.For dissimilar joints, i.e.

12、 welds between different steel grades, the filler material shall be suited for any intended heat treatment and for the operating temperature and operating fluid.Filler materials and auxiliary materials and welding flux shall be stored in such a way that they cannot be confused, and shall be treated

13、properly according to the manufacturers recommendations, e.g. drying of coated electrodes and welding flux before use.Manufacturing FacilitiesThe manufacturer shall have suitable facilities for forming (e.g. rolling of the shell courses), weld bevel preparation, preheating, welding and - where requi

14、red - heat treatment.Heat treatment facilities shall be inspected for proper function and accuracy at regular intervals.Testing Facilities and Test PersonnelThe manufacturer shall have qualified test and supervisory personnel, suitable testing equipment and facilities as well as working instructions

15、 for the intended testing.The equipment and facilities shall be checked for proper function and accuracy at regular intervals.Marking SystemsProcedures shall be implemented in the manufacturers works, which ensure an unambiguous correlation:of components to the material certificates;of welds to the

16、welder;of tested welds to the report of nondestructive tests and to each individual film;of pressure vessels to manufacturing documents and acceptance documentation.Design and FormGeneralThe manufacturer shall establish the technical documents required for the proper manufacture and testing of a pre

17、ssure vessel, by observing the specified requirements. Site welds shall be clearly indicated in these documents. A test assembly in the manufacturers works shall generally be considered and it shall be indicated, when the pressure vessel will be completed on site. The purchase order specifies which

18、manufacturing documents shall be submitted to the Purchaser or third parties for review prior to start of manufacturing.Welds in Pressure-Bearing WallsButt welds shall be welded with full penetration. Seams accessible from both sides shall be welded from both sides. For single-side welds, the weldin

19、g procedure shall be so selected that an integer root weld is achieved.Permanent backing strips shall be approved by Linde.For both-sides welded seams back-gouged root shall be checked for freedom of defects.An accumulation of welds shall be avoided; therefore, the following shall apply:Cross joints

20、 are not permitted;Distance of nozzle welds to circumferential or longitudinal welds: 3 x s (s = shell wall thickness), but not less than 50 mm;If the above specified requirements cannot be observed in a specific case, a 100 % nondestructive volume test shall be performed.Distance between parallel b

21、utt welds : 6 x s, but not less than 50 mm.Pressure-bearing welds should not be covered by attachments (e.g. saddles, reinforcement pads). If this is unavoidable, the welds which will later be covered shall first be ground flush with the base metal and the freedom of defects shall be verified by a v

22、olume test (radiographic/ultrasonic test).AttachmentsAttachments coming into contact with the fluid in pressure vessels in corrosive service with corrosion allowances 1 mm and vessels of stainless steel shall be welded with a continuous fillet weld. A venting of hollow spaces shall be provided for o

23、n the lowest point of the fillet weld by a short weld interruption. Tray rings in columns shall be seal-welded with a continuous weld on their upper side; the lower side can be welded with staggering.External attachments coming not into contact with the fluid shall be welded with a continuous fillet

24、 weld, irrespective of their stresses, so that rain and/or condensation water cannot penetrate into the gaps and lead to corrosion of the vessel wall. A venting of hollow spaces shall be provided for on the lowest point of the fillet weld by a short weld interruption.Welds in reinforcing pads of noz

25、zles (segment welds in opening reinforcements) shall not be arranged parallel to the longitudinal axis of the vessel. These seams shall be welded separately from the vessel.Venting of hollow spaces shall be performed for attachments such as saddles, block flanges, reinforcing pads with a venting bor

26、e # 6 mm, reinforcing pads with a tapped bore per segment for inspection purposes.Manufacturing and TestingGeneralManufacturing may be started only then, when the manufacturing requirements acc. to section 2 have been fulfilled.The documents reviewed in accordance with section 3.1 shall be binding f

27、or the manufacturing and testing of a pressure vessel. Deviations from these need the written approval of the authority(ies). In addition to the following general requirements, the material-specific requirements as per section 6 shall be observed.Page 4Issue 06.2003Weld Bevel PreparationFor fine-gra

28、ined steels with Re 355 N/mm2, high-temperature CrMo-steels and austenitic steels, thermal cut bevels shall be machined (e.g. by grinding) and tested for freedom of scale and cracks.If the bevels are not machined, the plasma process only is permitted for weld bevel preparation of austenitic steelsPa

29、int coats and other coatings shall be removed completely in an area 25 mm to the welding bevel.PreheatingIn accordance with the welding procedure specification, dependent on material, wall thickness and ambient temperature. At temperatures 0.25%) or high carbon equivalent (C + Mn/6 0.4) there is a r

30、isk of cracking in the heat affected zone because of the high level of hardness. Depending on the material analysis, wall thickness, welding procedure and ambient temperature, sufficient preheating is required.For elevated strength fine-grained steels (with Re 355 N/mm2), the risk of hydrogen-induce

31、d (cold) cracks shall be reduced by preheating, limited (controlled) heat input and - for wall thicknesses 30 mm only - hydrogen effusion treatment (soaking at 280 - 300 C for 2 to 4 hours). Fillet welds shall be welded in at least two passes, seam length for attachments at least 50 mm; nondestructi

32、ve testing of the welds not earlier than 48 hours after welding, if the welds are not subject to postweld heat treatment.High-Temperature Cr-Mo-SteelsHardness of weld deposit and heat affected zone shall not be more than 100 units above the hardness of the base metal, but not higher than 350 HV 10.

33、Verification on the component (random samples) and on production weld test plates, if required by code.Ni-Steels for Low Temperature ServiceFiller materials (austenitic or Ni-based) dissimilar to base metal are permitted for steels with Ni # 5% only. For dissimilar filler material it shall be verifi

34、ed by welding procedure qualifications and production weld test plates that the mechanical properties (yield strength, tensile strength) used for the dimensioning are met in the weld deposit.For steels with Ni # 5% : Remanent magnetism can deflect the arc and thus cause lack of fusion. Preventive me

35、asures are:no use of magnetic cranes, no transportation by train with electric overhead lines and no magnetic particle test;avoidance of accidential magnetization by electric conductors such as cables or electrical equipment;nondestructive testing of all pressure-bearing welds (100%) for lack of sid

36、e fusion.Austenitic CrNi-SteelsGrinding discs specially suitable for CrNi steel and brushes of CrNi steel shall be used for CrNi-steels only. Machining of austenitic steels spatially separated from ferritic steels or nonferrous metals.For single-side welding, root protection (argon or purging gas) is required.Interpass temperature # 200 , avoidance of overheating.Delivery condition metallic bright, i.e.