621 e3 pages fm Reconditioning of Metallic Gate, Globe, and Check Valves API RECOMMENDED PRACTICE 621 THIRD EDITION, AUGUST 2010 Reconditioning of Metallic Gate, Globe, and Check Valves Downstream Seg[.]
Valve Information
The owner must supply the reconditioner with essential information regarding the type of product that may have been present in the valve cavity, packing, and gasket, as well as any known issues related to the valve.
4.1.2 Any tag used shall be of a type and material that resists damage, fading, and inadvertent removal.
Material Safety Data Sheet
A Material Safety Data Sheet (MSDS) shall be provided for each product that may have been contained in the valves sent for reconditioning.
Preparation For Shipment To Reconditioner
Valves to be shipped to the reconditioner shall:
1) Be in the open or partial open position;
2 ASTM International, 100 Barr Harbor Drive, West Conshohocken, Pennsylvania 19428, www.astm.org.
3 International Organization for Standardization, 1, ch de la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, www.iso.org.
4 Manufacturers Standard Society of the Valve and Fittings Industry, Inc., 127 Park Street, N.E., Vienna, Virginia, 22180-4602, www.mss-hq.com.
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2) Have all residual product drained and/or flushed out of the body;
3) Be decontaminated sufficiently so that it can be disassembled and handled without special precautions;
4) Have end flange gaskets removed.
Valve Rerating
In cases where a valve must be de-rated due to repairs, the new rating must receive approval from the Owner; otherwise, the valve will be discarded Upon approval, the existing rating will be removed and substituted with the updated rating.
5 Inspection, Identification, and Disassembly of Valves
General
5.1.1 Immediately upon receipt, valves shall be marked to identify the Owner.
5.1.2 Valves shall be visually inspected and classified as 1) valves capable of being reconditioned, or 2) valves to be scrapped.
For valves that are not cost-effective to repair, it is important to salvage as many usable parts as possible These parts should be designated for use exclusively in valves from the same manufacturer, type, and material.
5.1.4 Scrapped valves and scrapped valve parts shall be disposed of in accordance with their Owner’s instructions.
Identification Number
Each valve must have a distinct identification number that can be traced back to the Owner's shipping documentation and relevant details, including special instructions and records of prior reconditioning.
Salvaged usable parts, excluding hand wheels, must be clearly identified for the Owner This identification should include essential details such as the valve manufacturer's name, size, type, pressure class, and trim Additionally, each part should have a unique identification number that begins with the letter "R."
When storing a valve or salvaged usable part prior to reconditioning, it is essential to stamp it with its identification number or attach a durable tag displaying the number The tag must be made of materials that withstand damage, fading, and accidental removal.
Traveler Documents
5.3.1 An Owner-approved traveler document or electronic file shall be developed and maintained for each valve and shall reference the valve identification number.
Traveler information must be continuously updated during the reconditioning process to accurately represent the current status of repairs, parts replaced, and any outstanding work Additionally, it should document any dimensional changes resulting from the reconditioning.
5.3.3 Unless otherwise specified, traveler information shall be archived by the reconditioner for a minimum of ten years.
Disassembly and Cleaning of Valves
5.4.1 Valves to be reconditioned shall be completely disassembled.
5.4.2 Old packing, gaskets, and bonnet bolting shall be removed and disposed of in accordance with owner’s instructions and/or applicable regulations.
All previous reconditioning tags must be removed, and the information from these tags should be documented in the reconditioned valve record Additionally, any OEM tags still attached to the valve should also be removed.
Immediately after disassembly, a new identification number must be metal stamped onto the valve's closure element, stem/shaft, and any removed seat rings, ensuring that these markings remain visible after reconditioning Stamping should occur on non-functional surfaces using low-stress methods If stamping is impractical, alternative methods such as tagging or electro-etching may be used, although all stems and closure elements for valves NPS 2 (DN 50) and larger must be stamped.
Unless the Owner specifies a particular cleaning method, valve parts must be thoroughly cleaned using standard techniques such as steam, chemical, sand/bead, or steel shot blasting It is essential to protect finished surfaces that could be damaged during the cleaning process.
5.4.6 Cleaning process shall remove all or nearly all paint, grease, rust, and product from both internal and external surfaces.
General
6.1.1.1 Welding procedures and welders shall be qualified in accordance with Section IX of the ASME Boiler and
6.1.1.2 Welding procedures shall be submitted to the Owner for approval prior to the start of welding.
6.1.1.3 Weld metal buildup and weld metal repairs, including any required post weld heat treatment, shall be performed in accordance with the approved procedures.
6.1.2.1 Welds, other than tack welds, shall be examined by the liquid penetrant method or by the nondestructive examination (NDE) method specified by the Owner.
6.1.2.2 NDE of parts and/or weld repairs shall be done in accordance with owner-approved NDE procedures and acceptance criteria.
6.1.2.3 SNT-TC-1A Level II technicians certified for the procedures per ASME Section V shall evaluate NDE results.
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When sourcing replacement parts, priority should be given to parts purchased from the Original Equipment Manufacturer (OEM) or an OEM-approved source If unavailable, salvaged parts from scrapped valves of the same manufacturer with matching identification are acceptable Additionally, parts manufactured in a reconditioning facility may be used, provided they receive approval from the Owner.
Replacement parts in the reconditioning facility must be manufactured using materials specified by the owner or, if not specified, the original valve manufacturer's materials that meet the referenced standard, including any necessary heat treatment Any changes in material group, such as from 13CR to austenitic stainless steel, require the owner's approval Additionally, documentation must include verification of the specific material used and its source.
6.1.3.3 As a minimum, the following components shall be replaced: a) Soft seats; b) Bonnet and cover bolting; c) Packing; d) Gaskets; e) Grease fittings.
Inspection of Valve Parts
6.2.1.1 Valve parts shall be inspected to determine their acceptability for re-use and/or extent of required repair.
6.2.1.2 Criteria for acceptability and extent of repair shall be the component’s ability to meet the Owner’s expectation for continued service in his facility.
6.2.2.1 Threaded parts shall be visually inspected for gross defects, such as missing or incomplete threads, defective thread profile, torn or ruptured surfaces, and cracks.
6.2.2.2 Surface texture of threaded parts shall be evaluated by visual or tactile comparison with texture specimens or surface measurement equipment.
6.2.2.3 Visual inspection shall be made without magnification Thread acceptability criteria shall be specified by the Owner in accordance with ASME B1.3.
Handwheel Nut
6.3.1 Handwheel nut shall be visually inspected for wear or excessive corrosion of the threads or contact area.
6.3.2 If the handwheel nut is defective, it shall be repaired or replaced.
6.3.3 If the handwheel nut is locked into place with a setscrew or some other device, the locking mechanism shall be in place and fully functional.
Handwheel
6.4.1 Handwheel shall be visually inspected for worn, bent, or broken spokes and rim.
The handwheel must be inspected to ensure it properly engages with the stem yoke nut In cases where the valve lacks a yoke nut, the inspection should confirm that the handwheel is correctly engaged with the stem.
A defective handwheel must be repaired using the suitable method for the specific defect Bent spokes, hubs, or rims can be straightened through pressing, while broken spokes or rims made from weldable materials may be repaired by welding.
6.4.4 If the defect(s) cannot be repaired, the handwheel shall be scrapped and replaced with one of similar size and material.
6.4.5 All parts of the handwheel and any repairs shall be free of burrs, metal splinters, and sharp metal edges.
Yoke
6.5.1 Yoke shall be visually inspected for defects and for proper alignment of the stem through the stem nut, packing chamber, back seat bushing, and wedge connection.
6.5.2 Defects shall be repaired by generally accepted repair procedures, such as welding or machining.
Stem Nut and Stem Nut Housing
6.6.1 Stem nut and stem nut housing shall be visually inspected for corrosion, galling, or wear of bearing surfaces.
6.6.2 Defects shall be repaired by welding (if of a weldable material), machining or other appropriate methods If the defects cannot be repaired, the nut/housing shall be replaced.
For optimal valve performance, it is essential that the thrust bearing, as specified by the OEM, is properly installed and free from significant corrosion or wear If the thrust bearing shows signs of deterioration, it should be replaced to ensure the smooth operation of the stem nut.
6.6.4 Internal threads of a tapped hole in the stem nut housing shall be visually inspected and defective threads shall be repaired and/or re-tapped.
6.6.5 Lubrication fittings shall be replaced.
6.6.6 If applicable, external threads on the stem nut shall be visually inspected for proper engagement to the handwheel nut.
6.6.7 Internal ACME threads of the stem nut shall be visually inspected for condition and proper engagement with the external threads of the stem in accordance with ASME B1.5 or B1.8.
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Stem Nut Retainer
The stem nut retainer should be visually inspected for signs of excessive corrosion and wear, while the threads must be checked for overall condition and proper engagement with the valve bonnet or yoke.
6.7.2 Defective stem nut retainer shall be repaired by welding and/or machining If defects cannot be repaired, stem nut retainer shall be replaced.
6.7.3 After assembly and before shipping, the stem nut retainer shall be tack welded, or otherwise locked, to the yoke.
Packing Gland Flange
6.8.1 Packing gland flange shall be visually inspected for excessive corrosion, cracks, and straightness.
6.8.2 Defective flange shall be repaired or replaced.
Packing Gland
The packing gland must undergo a visual inspection for signs of excessive corrosion or wear, and it should be dimensionally checked to ensure a proper fit with the stuffing box and stem, adhering to OEM specifications In cases where OEM dimensions and tolerances are unavailable, the clearances outlined in Figure A.1 may be utilized, provided they receive approval from the Owner.
6.9.2 A damaged or broken packing gland shall be repaired or replaced.
Back Seat Bushing
The effectiveness of a back seat bushing in sealing against the opposing angle of the stem is evaluated through a visual inspection for signs of corrosion, wear, and cracks Additionally, the sealing surface must have a finish with a roughness average (Ra) of 32 microinches (0.8 micrometers) or smoother.
6.10.2 A defective bushing shall be repaired with an owner approved repair procedure or the bushing shall be replaced.
Body and Bonnet
6.11.1.1 The stuffing box shall be visually inspected for corrosion, wear, or scoring of the bore wall.
The sealing area of the stuffing box bore, which interacts with the top six packing rings, can exhibit some pitting, as long as it does not exceed half the height of any single compressed packing ring.
The non-sealing area of the stuffing box bore does not require inspection for surface finish Any harmful areas that could potentially damage the packing during installation must be properly dressed.
6.11.1.4 A defective stuffing box shall be repaired by machining or welding and re-machining Unless otherwise specified by the Owner, sleeving of the stuffing box is prohibited.
The stuffing box must have a surface finish of Ra 175 àin (4.5 àm) or smoother, and its dimensions should comply with API 600, sections 5.9.2 and 5.9.3 Additionally, the stuffing box bore must adhere to the tolerances specified for the nominal diameter in the API standards.
600, 5.9.3 is not allowed However, an over tolerance as specified by the packing manufacturer, but not to exceed
The stuffing box bore may be assumed to be 2% as specified in section 5.9.3 of API 600, or 0.045 inches (1.143 mm), pending approval from the Owner Additionally, for PTFE Vee Rings, the required surface finish of the stuffing box must be Ra 64 or better.
6.11.2.1 Body and bonnet castings shall be visually inspected for defects in accordance with MSS SP 55.
6.11.2.2 Some pitting or areas of localized corrosion are allowed provided the requirements of Table 2 are met.
6.11.2.3 If deemed necessary, castings may be inspected with NDE (radiography or other method) to determine extent of defects.
6.11.2.4 WC6, WC9, LC2, LC3, C5, C12, and austenitic stainless casting metallurgy shall be verified by positive material identification (PMI) and by NDE as specified by the owner.
The wall thickness of bonnet castings must be measured at least at two locations, while body castings require measurements at a minimum of three locations If visual inspections reveal areas needing further verification, additional measurements should be taken Acceptable wall thickness must adhere to the specifications outlined in Table 1 Furthermore, the locations of the measurements and the corresponding thicknesses must be documented in the data file of each valve.
Pitting or localized corrosion that decreases the valve wall thickness below the minimum allowable limits outlined in Table 1 may be deemed acceptable under specific conditions Firstly, the maximum diameter of a circle enclosing the pitting or corrosion must align with the specifications in Table 2 Secondly, the minimum distance between the edges of circles that enclose adjacent pitting or corrosion areas must also conform to Table 2 Lastly, the wall thickness at the site of the pitting or corrosion should be at least 75% of the minimum wall thickness specified in Table 1.
Unacceptable casting defects must be removed and repaired; if repair is not feasible, the casting should be discarded Repairs involve welding the defective areas and any regions with insufficient wall thickness The surfaces of the weld metal must be ground or machined to achieve a smooth finish that meets the standards of acceptable castings Additionally, post-weld heat treatment is necessary for carbon steel casting weld repairs as specified in ASTM A-216, Para 10.3.
6.11.2.8 Weld repairs on WC6, WC9, C5 and C12 castings shall be done in accordance with ASTM A-217, Par 9.3 Owner shall specify NDE procedures to be used.
6.11.2.9 Weld repairs for all stainless steel castings shall be in accordance with ASTM A-351.
Nipples, pipe plugs, or hinge pin plugs installed in tapped openings of the body, bonnet, or stuffing box must be removed for inspection The threads should be checked and repaired if needed Replacement plugs must be crafted from new bar stock, with the material being equal to or better than that of the body material.
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Table 1 outlines the minimum thickness of shell walls and minimum diameters of stem dimensions for various valve sizes, ranging from 150# to 2500# The specifications include detailed measurements in inches and millimeters for different NPS sizes, ensuring compliance with industry standards It is crucial to note that the shell comprises both the body and the bonnet, and the minimum wall thickness must be measured from internal wetted surfaces, excluding liners or linings For inspection purposes, the wall thickness of valve bodies and bonnets after reconditioning must meet or exceed the minimum values listed Additionally, plugs should be securely screwed and seal welded unless specified otherwise, and replacement nipples must match the chemical composition and strength of the original materials All replacement components are subject to applicable heat treatment, and positive material identification (PMI) of all alloy materials is mandatory.
6.11.3 Body-to-Bonnet Flanges and Gasket Surfaces
6.11.3.1 Body-to-bonnet flanges shall be inspected for corrosion and overall condition.
Unless specified by the Owner, the minimum flange thickness after machining or any necessary weld repair and re-machining must not be less than 0.032 inches (0.8 mm) below the original thickness.
Defective surfaces surrounding the flange bolt holes must be repaired appropriately Any weld repairs should be machined or ground to ensure that the nut bearing surfaces are parallel to the flange gasket face within a tolerance of ±1 degree Additionally, bolt holes should be spot faced according to MSS SP 9 standards as required.
Both body-to-bonnet gasket sealing surfaces must undergo a visual inspection for any signs of corrosion, wear, cuts, or scoring Any identified defects should be repaired to meet OEM surface finish standards, or may follow the specifications in Table 3 if approved by the Owner It is crucial that repairs do not change the design dimensions of the body-to-bonnet joint, which are essential for maintaining proper gasket compression control.
Table 2—Allowable Pitting and Localized Corrosion
Maximum Diameter of Circle that can Enclose Pitting/Corrosion
Minimum Edge-to-Edge Distance Between Adjacent Enclosure Circles
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6.11.3.5 Material and surface finish of different gasket types shall conform to Table 3
6.11.4 Body End Flanges, Gasket Surfaces, and Face-to-Face Dimensions
6.11.4.1 Face-to-face dimensions shall be checked for compliance with Table 4
6.11.4.2 Dimensional non-conformances shall be corrected by weld metal build up and/or machining.
6.11.4.3 Unless otherwise specified, gasket surface finish shall be a Ra of 125 àin (3.2 àm) to 250 àin (6.4 àm).
Defective surfaces surrounding bolt holes must be repaired as needed Weld repairs should be machined or ground, and bolt holes must be back spot faced to ensure smooth nut bearing surfaces and allow for unrestricted bolt installation.
Table 3—Gasket Material and Surface Finish
Gasket Type Material Surface Finish
Flexible graphite with metal insert Greater than 98 % graphite, containing less than
100 ppm leachable chlorides, adhesively bonded to 0.002 in (0.05 mm) minimum thickness flat or corrugated 304 or 316 SS metal reinforcing agent
Commercial grade PTFE with or without reinforcing fillers Made of commercial PTFE suitable for temperatures up to 450 °F (232 °C) Glass or ceramic fillers may be used as reinforcing agents
Corrugated metal Soft iron Approx 63 àin (1.6 àm)
Spiral wound Gasket metal winding of TP 304SS or TP 316L SS with filler material of PTFE or flexible graphite 125 àin to 250 àin
Oval/rectangular ring Soft iron Ring Joint groove with a 32 àin to 63 àin (0.8 àm to 1.6 àm) finish
Pressure seal gasket Owner shall specify gasket material and any plating to be used, if different than OEM Approx 32 àin (0.8 àm)
NOTE 1 Flexible graphite with metal insert gaskets are suitable for use in Class 150 as per API Standard 600.
NOTE 2 Owner may specify alternative materials to be used as reinforcing metals, wire, and windings and filler materials.
Table 4—Face-to-Face Dimensions Valve Size Face-to-Face Dimension Allowable
Variation from ASME B16.10 in (mm)
Holes measuring 16 and larger, as well as those 400 and larger, must maintain a tolerance of ±0.187 (±4.8) It is essential that back facing or spot facing does not compromise the flange thickness, ensuring compliance with the minimum flange thickness requirements outlined in ASME B16.5 or as specified by the Owner.
6.11.4.5 Reduction of flange thickness below the minimum thickness requirements of ASME B16.5 is allowed with approval by the Owner stating the thickness permitted.
Body Guides
6.12.1 Body guides shall be visually inspected to verify that the wedge slides smoothly.
6.12.2 Body guides may be repaired by grinding or machining or by weld metal buildup and grinding or machining.
Body Seat Ring(s)
6.13.1 Body seat ring(s) shall be visually inspected for corrosion, wear or cuts, and for any apparent leakage between the seat ring and the valve body.
If the valve body and seat ring(s) are in suitable condition, the sealing surfaces of the seat ring(s) should be repaired through machining or lapping to create chamfered edges and a flat surface approximately 1/16 inch (1.6 mm) thick.
1/8 in (3.2 mm) wide with a Ra of 32 àin (0.8 àm) or smoother finish.
If the seat ring(s) require extensive repairs, several procedures may be implemented with the Owner's approval The sealing surface(s) of the seat ring(s) can be replaced or repaired using a weld metal deposit suitable for the required trim, ensuring that the repaired surfaces meet the hardness minimum specified in API 600, Table 8 The Owner will determine the necessity and extent of any hardness testing, which must also be approved Alternatively, new seat ring(s) that comply with API 600, Table 8 may be installed In cases where leakage between the seat ring(s) and body is suspected, the seat ring(s) should be seal welded into the body using an approved welding procedure that is compatible with both materials For ASME Class 600 and higher pressure class valves, all non-welded seat rings must be seal welded unless specified otherwise.
6.13.4 Use of bushings, shims, epoxy, glue, grease, or thread sealant between the body and seat ring(s) is prohibited.
Wedge Guides
6.14.1 Wedge guides shall be visually inspected for corrosion or wear.
6.14.2 Wedge guides shall also be physically checked to ensure proper fit to the body guides and guidance of the wedge into the seat rings.
6.14.3 Defects shall be repaired by weld buildup and/or machining, grinding, or milling.
Wedge, Globe, Disc, and Clapper
6.15.1 Wedge, globe, disc, or clapper (including the arm, hinge pin, and cap) assembly shall be visually inspected for corrosion, wear, or pitting.
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Defective wedges, globes, discs, or clappers must be either replaced or repaired through methods such as weld metal buildup, machining, grinding, or lapping After repairs, the seating surface finish should achieve a roughness average (Ra) of 32 microinches (0.8 micrometers) or smoother.
The seating design for a wedge gate valve must ensure sufficient seating both prior to and following the wear of the seating surfaces When the valve is fully closed, the wedge seating surface should allow for an additional closing travel that meets or exceeds the specifications outlined in Table 5.
If the final fitting of a wedge to the seat rings leads to a closing travel that is less than the specifications in Table 5, it is permissible to build up the wedge sealing surfaces with weld metal This adjustment ensures that there is sufficient distance between the seat ring contact area and the edge of the wedge sealing surface.
Split wedge gate valves must have all weld metal buildup on the face of the wedge, while any buildup on the backside of the wedge halves to address wear or machining of the sealing surfaces is not allowed.
Stem
6.16.1 Stem shall be inspected for straightness and damage to the threads, backseat, and tee-head.
6.16.2 Portion of stem that slides through the packing shall be inspected for corrosion, pitting, wear, and taper.
6.16.3 Out-of-straightness of the entire length of the stem shall not exceed 0.001 in./in (0.001 mm/mm).
6.16.4 Stem threads shall properly engage the internal threads of the stem nut in accordance with ASME Standard B1.5 and B1.8.
6.16.5 Stem backseat shall have a surface finish Ra of 32 àin (0.8 àm) or smoother and shall ensure proper seating against the sealing surface of the bonnet backseat.
6.16.6 Tee-head shall be inspected to verify proper engagement to the wedge.
The minimum stem diameter must comply with Table 1, and any permitted tolerances should follow API 600, Section 5.8.1 Defective stems must be replaced, or if approved by the Owner, may be repaired using a qualified procedure suitable for the specific defect, which may include welding or machining All stem weld repairs and qualification procedures must adhere to Annex B standards.
6.16.8 Repaired stem shall be inspected with liquid penetrant examination or an alternative method when approved by the Owner Stem packing area shall have: a) No rejectable defects;
Table 5—Minimum Wear Travel Valve Size
Minimum Wear Travel in (mm)
The specifications require a surface finish of Ra 32 àin (0.8 àm) or smoother, with a maximum stem diameter tolerance set at the lesser of 150% of the value specified in Section 5.8.1 of API 600 or 1/32 in (0.8 mm) below the manufacturer's original Additionally, there should be a maximum taper or cylindrical variation of 0.003 in (0.08 mm) across the entire stem packing area.
Body-To-Bonnet Joint Bolting
6.17.1 Unless otherwise specified, body-to-bonnet bolting shall be new bolts and nuts as specified by ASTM A193/ A320 and A194 Heavy Hex nuts shall be used for API 600 repair.
6.17.2 Bolting shall have readily visible marking imprinted into all bolts and nuts.
6.17.3 Special or other bolting requirements shall be in accordance with the Owner’s engineering piping specification as supplied on the Owner’s purchase order or as instructed by the Owner’s representative.
Packing Gland Eye Bolts
6.18.1 Packing eyebolts shall be visually inspected for corrosion or other damage Damaged eyebolts shall be replaced.
6.18.2 Unless otherwise specified, nuts shall be replaced as specified by ASTM A194.
6.18.3 Special or other bolting requirements shall be in accordance with the Owner’s engineering piping specification as supplied on the Owner’s purchase order or as instructed by the Owner’s representative.
Packing
6.19.1 Packing shall be in accordance with API 600, Section 5.9.1 and Table 6.
Packing shall consist of a carbon and/or graphite ring arrangement, utilizing Owner-approved Type A or Type E braided graphite filament for the top and bottom rings, along with Type B flexible graphite die-formed endless inner rings, unless specified otherwise, as outlined in Annex A.
6.19.3 Graphite packing shall be suitable for steam and petroleum fluids for the temperature range from 20 °F (–26 °C) to 1000 °F (538 °C), and unless otherwise specified, shall contain a corrosion inhibitor.
When required, PTFE Vee Ring packing or lattice braid PTFE filament packing must comply with Annex A Any special or additional packing requirements should align with the Owner's engineering piping specifications provided in the purchase order or as directed by the Owner's representative.
6.19.5 Packing cross section shall be consistent with the final dimensions of the reconditioned stuffing box and stem.
Body-To-Bonnet Joint Gasket
Body-to-bonnet joint gasket shall conform to Table 3 unless special or other gasket material requirements are specified by the Owner.
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Before assembling valve components, it is essential to apply an Owner-approved rust preventative to the internal surfaces, with the exception of the body and bonnet gasket surfaces, seating surfaces, and stem This requirement does not apply to austenitic stainless steel materials.
7.2 Gasket surfaces and seating surfaces may be lubricated with light oil not heavier than kerosene.
7.3 Stem threads shall be lubricated with an Owner-approved dry film lubricant Lubricant shall be injected into the stem nut housing.
7.4 After testing, stem packing shall have a minimum of 30 % of the packing gland available for field adjustment of the stem packing.
7.5 Body-to-bonnet joint bolting shall be tightened by a method and in a pattern, that achieves uniform compression and sealing of the gasket.
In the fully closed position, the stem's end must be flush with the top of the stem nut at a minimum, and it should not exceed the maximum allowable projection above the stem nut as specified by API 600.
8.1 Unless a more restrictive test is required by the Owner, pressure test of assembled valves shall be in accordance with API 598 and Annex C of this RP.
8.2 Additional testing shall be done at the request of the Owner as stated in the Owner’s purchase order or as instructed by the Owner’s representative.
8.3 Copy of the test results shall be included in the reconditioning work documentation.
9.1 Carbon steel and ferritic alloy steel valves shall be cleaned and externally coated with a general purpose aluminum or silver color paint.
9.2 Machined end flange gasket surfaces, butt weld ends, and stems shall be left completely paint free.
9.3 Machined and threaded surfaces (excluding stem threads) exposed to the atmosphere shall be coated with an owner-approved rust preventative.
9.4 Valves shall have the end port openings covered and protected in accordance with API 600.
9.5 If specified, valves shall be secured in boxes or on wooden pallets for shipment.
9.6 Moving parts on valves shall be lubricated with an approved lubricant specific to the design and function of the part.
9.7 If special preparations, cleaning, or packaging are required prior to shipping, they shall be carried out in accordance with the Owner’s instructions.
10 Tagging and Reconditioning Facility Identification
Each reconditioned valve must have a stainless steel plate (valve tag) permanently affixed to its body or bonnet, containing essential information This includes a statement confirming reconditioning per API 621, the name of the reconditioning facility, and the reconditioning date Additionally, the tag should specify the valve's size and type, body/bonnet material, stem material, body and gate seating surface material, packing material, gasket material, and a unique valve identification number starting with "R." It must also indicate the valve's pressure rating at 100 °F (38 °C) along with the pressure rating class number, and note any reductions in maximum pressure/temperature ratings due to changes in packing, bolting, or gasket materials, as outlined in Section 4.4 Lastly, the original equipment manufacturer (OEM) nameplate must be removed.
10.2 Tag shall have rounded corners.
10.3 Valves that are too small to have the tag directly attached shall have the tag attached to the valve body/bonnet with 0.035 in (0.9 mm) (minimum) stainless steel wire.
10.4 If reconditioning included any special cleaning or other preparations for a specific service, an additional tag shall be wired to the valve identifying the special preparations performed.
Each reconditioned valve must display the name of the reconditioning company and the reconditioning date (month and year) stamped in low stress characters ranging from 3/8 in (9.52 mm) to 1/2 in (12.7 mm) The stamping should be placed on a nonfunctional surface: for flanged valves, it should be on the outside diameter of the body or end flange, while for other valves, it should be in the bonnet area In cases where stamping is impractical for small valves, the method and location must receive approval from the Owner.
This Annex covers requirements for materials, design, and installation for stem packing for valves being reconditioned in accordance with this RP.
Type A Carbon or graphite wiper rings having a yarn property carbon assay of 98 % minimum and with corrosion inhibitor applied at the time of manufacture.
Type B Graphite die-formed rings are crafted from 98% pure carbon graphite or higher, incorporating a corrosion inhibitor These rings achieve a nominal density of 70 lbs/ft³ (±5 lbs/ft³) following the die forming process.
Type C PTFE Vee rings incorporating a heavy wall and heel section A minimum of two pressure rings together with male and female adapters shall be used.
Type D Lattice Braid continuous filament PTFE fiber treated with PTFE dispersion and an inert ingredient.
Type E Flexible graphite foil wiper rings reinforced with braided Alloy 600 (UNS N06600) filament.
A.3.1 Rings shall contain no asbestos.
A.3.2 Leachable chloride content of the rings shall be limited to 100 ppm maximum.
A.3.3 Total sulfur in the rings shall be 1000 ppm maximum.
A.3.4 Unless otherwise specified, packing shall contain no binders, lubricants, or other additives.
Spacers or bushings used to fill stuffing boxes of excessive depth on gate and globe valves shall:
A.4.1 Be compatible with the stem material.
The valve bonnet must be constructed from carbon or an owner-approved equivalent material that offers equal or superior corrosion and temperature resistance Additionally, the material should possess a hardness that meets or exceeds the specified requirements.
50 HB different than the stem hardness The use of carbon bushings shall be limited to packing chambers that have a flat bottom.
A.4.3 Conform with the dimensional clearances in Figure A.1.
A.5.1 If a lantern ring is specified in the stuffing box for an external connection, it shall be aligned with the external connection or placed in accordance with the owner’s instructions.
Packing rings positioned directly above and below the lantern must be Type A wiper rings Alternatively, if Vee ring packing is utilized, a female adapter should be placed immediately below the lantern ring, while a male adapter should be positioned immediately above it.
A.6 Flexible Graphite Packing for Block Valves
A.7 PTFE Vee Ring Packing for Block Valves
A.8 Lattice Braid PTFE Filament Packing for Block Valves
Stem-to-gland radial 0.035 in to 0.060 in.
Packing spacer-to-stem 0.035 in to 0.060 in.
Gland-to-stuffing box bore
Bonnet back seat-to-stem radial clearance of mfg. std plus up to 0.0200 in. additional
R ECONDITIONING OF M ETALLIC G ATE , G LOBE , AND C HECK V ALVES 19
Figure A.3—Flexible Graphite Packing for Block Valves
NOTE 1 There shall always be at least one Type A or Type E ring at the top and bottom of the stuffing box.
For optimal performance, it is recommended to use a minimum of three and a maximum of four Type B rings in the stuffing box, depending on its depth Additionally, a spacer can be utilized at the bottom of the stuffing box if needed.
NOTE 3 Pre-formed flexible graphite rings shall be installed as continuous rings over the end of the threads
Slipping cut rings of flexible graphite around the stem is not permitted.
NOTE 4 Wrapping flexible graphite ribbon around the stem and using the packing gland and eyebolts to form the flexible graphite ring inside the stuffing box is not permitted.
Flexible graphite die-formed rings
R ECONDITIONING OF M ETALLIC G ATE , G LOBE , AND C HECK V ALVES 21
Figure A.4—PTFE Vee Ring Packing for Block Valves
A minimum of four rings must be utilized, consisting of one male adapter, two pressure rings, and one female adapter If the stuffing box is excessively large, the number of pressure rings should be increased to adequately fill the remaining space in the stuffing box.
NOTE 2 Vee rings shall be installed as a continuous ring Cutting of Vee rings is not permitted.
Figure A.5—Lattice Braid PTFE Filament Packing for Block Valves
NOTE Braided packing shall be scarf cut and individual rings shall be installed so that the cut in each ring is offset approximately 90° from the previous ring.
This Annex covers requirements for weld overlay of stems for valves being reconditioned in accordance with this RP.
B.2.1 Weld overlay of stems shall be done by undercutting the defective stem packing area and rebuilding with a weld metal overlay Undercutting shall be done by machining.
B.2.2 Reconditioner shall weld overlay only those stems for which a stem base material/ filler metal combination has been specifically qualified and approved.
B.2.3 Maximum allowable undercutting shall be to the thread root diameter.
B.2.4 Weld overlay is not allowed on stems with a diameter of 0.750 in (19.05 mm) or smaller in the packing area.
B.2.5 After welding, the stem packing area shall be machined.
B.2.6 After machining, welded area shall be subjected to 100 % dye penetrant examination Examiner shall be SNTTC-1A Level II qualified, as a minimum No indications are allowed in the packing contact area.
Defective weld areas can be repaired using the specified stem weld procedure, provided that the pitting or defective weld is first machined to create an undercut The entire undercut area must then be welded according to this procedure It is important to note that spot welding of individual defects or pits is not allowed.
B.2.8 Repair of stem T-head by weld build-up is not permitted.
B.2.9 All 300 series high carbon (C > 0.035) stainless steel stems, after weld repair is completed, shall be solution annealed and subjected to dye penetrant examination.
B.3 Procedure Qualification and Sample Preparation
B.3.1 Weld procedures shall be qualified in accordance with Section IX of the ASME Code (QW-450 for weld metal build-up and corrosion resistant or hardfacing overlay).
B.3.2 Weld overlay by SMAW welding is prohibited.
B.3.3 A weld procedure shall be qualified for each stem material and filler metal combination to be used for repair.
B.3.4 Reconditioner shall provide to the owner written notification of the stem material/filler metal combinations to be qualified.
B.3.5 Reconditioner shall prepare two samples from either 1.250 in (31.8 mm) or 1.375 in (34.9 mm) diameter API
600 valve stems for each stem material/filler metal combination to be qualified Owner shall approve the samples before qualification of the procedure begins.
B.3.6 Owner shall be notified when the preparation of the samples will commence.
B.3.7 Reconditioner shall provide to the Owner a copy of the procedures to be qualified.
B.4.1 One stem sample shall be subjected to a stem pull test in accordance with API Std 591 for each stem material and filler metal combination that is being qualified.
A specimen measuring 3/8 in (9.52 mm) wide, excluding a stem with a hard facing overlay, must be extracted longitudinally from the center of the second sample stem A side bend test should then be conducted following ASME Section IX, QW-453 Any indication of weld metal disbonding will result in the disqualification of the repair procedure.
B.4.3 A specimen from the second stem sample shall be micro etched and photomicrographed to determine proper fusion.
B.4.4 A hardness profile shall be made across the centerline of the stem. a) 410 stainless steel with a 410 stainless steel overlay:
1) Unless otherwise specified, a hardness between 200 HB and 275 HB shall be maintained, both before and after welding.
2) Hardness of the heat-affected zone shall be within 80 HB of the base metal hardness. b) 300 series stainless steel with a 300 series stainless steel overlay:
1) Hardness of the weld overlay shall be within 50 HB of the base metal hardness. c) 410 stainless steel base with a corrosion resistant overlay:
1) Post weld heat treatment is required.
2) A maximum allowable reduction of hardness shall be a maximum of 30 HB.
3) Unless otherwise specified, final base metal hardness shall be between 200 HB and 275 HB.
4) After heat treatment hardness of the heat-affected zone shall be within 50 HB of the base metal.
5) PMI shall be done on the weld overlay using an analyzer approved by the owner.
6) Chemical analyses shall be done for procedure qualifications and laboratory tests. d) 300 Stainless steel base with a hard facing overlay:
1) Postweld heat treatment is required.
2) A maximum allowable reduction of hardness shall be a maximum of 30 HB.
3) Unless otherwise specified, final base metal hardness shall be between 200 HB and 275 HB.
4) After heat treatment, hardness of the heat-affected zone shall be within 50 HB of the base metal hardness.
This Annex covers requirements for testing of valves being reconditioned in accordance with this RP.
C.2.1 Tests shall be conducted in a manner that verifies the pressure integrity of the valve body and the valve seat(s).
Reconditioned valves must undergo specific tests unless otherwise stated, including a shell and backseat test, high pressure seat tests for both sides, and low pressure air tests for both sides.
During the testing of gate valves, it is essential to pressurize the valve body cavity by allowing the test medium to flow through the valve while the wedge is being closed onto the seats.
C.2.4 Preferably, the seat test shall be performed with the valve stem in the horizontal position, the valve bore in the vertical position, and one side of the valve open.
For high pressure seat tests, valves can be tested with the stem in a vertical position by employing double flanging on both sides and utilizing a pipe stand In the case of low pressure air seat tests, double flanging on both sides and the use of a bubbler is allowed, provided it receives approval from the Owner.
C.2.6 Unless a more restrictive test is specified by the Owner, test pressures, test durations, test fluids, and leakage rates shall conform to API Std 598.
C.3.1 Test equipment that may conceal or reduce disqualifying conditions from being easily detected shall not be used.
Pressure test gauges must be calibrated to the National Bureau of Standards within the last year and must be in proper working condition during the test.