Repair Procedure

OWNER

CLIENT: Sabz Engineering Company

National Iranian Gas Company IGAT 5 Gas Compressor Stations DOCUMENT TITLE

DOCUMENT No.

TASHA DOC. NO.

602-106-TS 602-106-TSH-VDH-VD-016 016 Rev. 0 REPAIR PROCEDURE

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CONSURTIUM:

TASHA Manufacturing Company SABZ Engineering Company FBM Hudson Italiana FBM KNM FZCO.

REPAIR PROCEDURE FOR SPY-2-1106/2106/3106/4106-EA-101

TASHA DOC. NO.

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602-106-TSH-VD-016 602-106-TSH-VD-016 Rev. 2

5 (EXCLUDING COVER SHEET)

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13/04/2006

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9/1/2006

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17/08/2005

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602-106-TSH-VD-016 Rev. 0 REPAIR PROCEDURE

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1- Argument and Scope 2- Reference 3- Application Field 4- Base Material Repairs 5- Weld metal Repairs 6- Defect Removal 7- Welding Repair Cavity Preparation 8- Preparation of damaged holes for repairing 9- Welding 10-Examination of weld Repairs 11-PWHT 12-Hardness Test 13- Documentation

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1- Argument and Scope This procedure describes methods of base metals and welds repairing with or without the use of welding. 2- References ASME Sec .I ASME Sec. VIII Div.1 Welding Spec (602-000-ME-SP-003-D00) 3- Application Field This procedure shall be applied to performer repairs with or without the use of welding .It is in accordance with applicable code. 4- Base Material Repairs Surface defects shall be considered unacceptable if the defect extends below the specified minimum wall thickness .These defects shall be repaired and examined according to paragraphs 6 -7-8 5- Weld Metal Repair Superficial defects, shall be removed, repaired and examined in accordance with paragraphs 6-7-8 6- Defect Removal 6-1-Superficial defects Superficial defects may be removed by means of grinding or machining without subsequent welding repair, taking care of the following: -The removing section thickness is not reduced below the minimum design thickness required. -The depression, after defects removal is grinding smooth and uniform with the surrounding surface. -NDT examinations of repaired zone give satisfactory results. After the removal the defect, the groove shall be examined, using either the MT or PT In accordance with NDT procedure. 6-2-Welding Repair Cavity Preparation Grinding, chipping machining or thermal gouging may remove all defects, all the conditions from the applicable welding procedure specification (WPS) such as: preheat, interpass, max heat input etc. shall be met and subsequently the prepared cavity be grinded to remove a min. of 1mm of material. When grinding on stainless steel, grinding wheels shall be rubber or resin bonded aluminum oxide or silicon carbide material. Tools and materials previously used on carbon steel surfaces shall not be used on stainless steel surfaces.

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Before welding repair is performed, the cavity shall be examined by liquid penetrant or magnetic particle methods to ensure that the defect has been removed and reduced to acceptance limits. 6-3-Preparation of damaged holes for repairing by means welding Damage of holes during drilling operation due to tool breakage etc. Treads damaging while plugs assembling Before welding repair is performed, parts of tools or parts of damaged threads eventually present shall be removed. The hole shall be examined by liquid penetrant or magnetic particle methods to ensure that the defect has been removed and that the surface for the welding is sound. 7- Welding Welding repair shall be made using one of the qualified WPS for the type of base material involved, even if the cavity-holes shape is different from the type of joint that the WPS shows. The repair area shall be preheated and maintained at a minimum temperature of 200 F (93 C) during welding. Welding repair shall be made by qualified welders. For base material repairs and for repairs in the welds made by a welder other then the original welder, the repair welder shall apply his symbol adjacent to the repaired area. ◦

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8- Examination of weld Repairs Each base metal's weld repair shall be examined according to the procedure specified for the actual product. As a minimum a visual examination shall be conducted on to the repaired area. Each weld repair in welds shall be re-examined by the methods of examination and limits of imperfections required for the original welds. Individual welders or welding operators shall be re-tested and, if necessary, retrained, when their repair rates consistently exceed 5% over a period of three weeks. Repair rates shall be calculated as follows Repair Rate = Total length of weld rejected by RT or UT × 100 Total length of weld rejected by RT or UT 9- PWHT All repairs involving welding shall be made prior final PWHT if required. Any weld repair made after final PWHT shall be reheated in accordance with PWHT procedure approved for the project. Final PWHT (after repair) shall be done before hydro test. If during hydro test weld repair is required, after repairing, PWHT and hydro test shall be repeated with their non-destructive test and as per relevant procedure.

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All non-destructive examination performed after repair shall be recorded in accordance with the applicable NDE procedure.NDE reports shall show all identifications data of the repaired item and/or weld as well as the letter R (R2-R3-etc. if more than one repairs). In addition, the above letters shall be shown on radiographs as of the radiographic image, when RT is required. 11- Repair Where PWHT is a code requirement only, welding after PWHT without additional PWHT is permitted only for the following:

Repair welds in carbon steel and nickel alloy steels equipment in accordance with the repair procedure (602-106-TSH-VD-016-REV1) and following requirements: - The total repair depth is limited to 25mm.The total depth of a weld repair shall be taken as the sum of the depths for repairs made from both sides of a weld at a given location - The repair excavation is subject to 100% MT. - Only matching low hydrogen consumable shall be used. - A temper bead welding technique is employed for the final weld pass on nickel alloy steel equipment. - A welding procedure qualification using the same welding process and consumable demonstrates acceptable hardness levels of less than (300HV for utility service and 248HV for other services) when tested in accordance with the requirement in paragraph 13. External attachment welds and seal welds on carbon steel equipment in accordance with the following requirements: - Thickness through the weld throat is limited to 13mm - Only matching low hydrogen consumable shall be used - A temper bead welding technique is employed for the final weld pass on nickel alloy steel equipment. - A welding procedure qualification using the same welding process and consumable demonstrates acceptable hardness levels of less than (300HV for utility service and 248HV for other services) when tested in accordance with the requirement in paragraph 13. After the finished repair weld has reached ambient temperature, it shall be inspected using the same NDT that was used in welding plan. If the MT method is used, only the alternating current yoke type is acceptable. In addition, welded repairs greater than 3/8 in. (10mm) deep in materials and in welds that are required to be radigraphed in accordance with NDT procedure. The vessel shall be hydrostatically tested after making the welded repair.

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12- Hardness Test Hardness testing shall be performed in accordance with EN 1043-1. Specimens for hardness testing from test pieces in the 5G or 6G positions shall be taken from the area of weld representing the minimum heat input. 13- Documentation All non-destructive examination performed after repair shall be recorded in accordance with applicable NDE Procedure. NDE reports shall show all identification data of the repaired items and/or weld in accordance with applicable code ASME Sec. VIII Div.1, 2001 Edition. In addition it shall be shown on radiographs as o f radiographic image when RT is required.

National Iranian Gas Company IGAT 5 Gas Compressor Stations No . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Item No.

Report for Repair Activities for Air Coolers Repair QC Result Repair Description Work Order Tasha Client Owner Serial No.

Date

Repair Procedure

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