GUJARAT NARMADA VALLEY FERTILIZERS & CHEMICALS LIMITED

Transcription

1 CONTENTS 1. Scope 2. Referenced Documents 3. Abbreviations 4. Materials and Manufacture 5. Dimensions 6. Inspections and Tests 7. Markings 8. Preparation for Shipment - 1 -

2 1. Scope 1.1 This specification covers the general requirements for materials, manufacturing, inspection and tests of forged steel flanges. This specification applies to the following materials: - ASTM A105: Forgings, Carbon Steel, for Piping Components - ASTM A182: Forged or Rolled Alloy-Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High- Temperature Services 1.2 The specific requirements are not included in this specification, which shall refer to "Piping Material Specification" and "Piping Material Specification for Special Material". 1.3 For inquiring and ordering purposes, this specification shall be accompanied by Bill of Quantity, which lists size and quantities required against Item Code. 2. Referenced Documents The following documents shall form an integral part of this specification to the extent specified herein. 2.1 Codes and Standards Any codes and standards to be used shall be the latest editions issued before November, a) ANSI Standards B.20.1 Pipe threads B16.5 Steel Pipe Flanges and Flanged Fittings B16.25 Butt Welding Ends B31.3 Chemical Plant and Petroleum Refinery Piping B36.10 Welded and Seamless Wrought Steel Pipe B36.19 Stainless Steel Pipe B46.1 Surface Texture b) API Standards 605 Large Diameter Carbon Steel Flanges c) MSS Standards SP-25 Standard Marking System for Valves, Fittings, Flanges and Unions d) ASTM Standards A153 Zinc Coating(Hot-dipped) on Iron and Steel Hardware A370 Test Methods and Definitions for Mechanical Testing of Steel Products A751 Methods, Practices, and Definitions for Chemical analysis of Steel Products A788 Steel Forgings, General Requirements 2.2 Project Specifications Piping Material Specification Piping material Specification for Special Materials 3. Abbreviations The words used in this specification and purchase order documents are abbreviated as follows: - MT: Magnetic Particle Examination - NPS: Nominal Pipe Size - PT: Liquid Penetrant Examination 4. Materials and Manufacture 4.1 The material type, specification and grade shall be strictly in accordance with the standards referred to this specification. 4.2 All material shall be new material with all surface clean and free from defects, weld spatter, arc strike, rust, dirt, sand, scale, paint or any other foreign substances. 4.3 All flanges shall be of forged one piece material(seamless), and plate may not be - 2 -

3 substituted without written approval from the Purchaser. 4.4 End flange facing shall be finished as follows: - Compressed asbestos and: Stock finish with roughness of TFE sheet gasket 125 to 500 AARH - Spiral Wound Gasket: Smooth finish with roughness of 125 to 250 AARH 4.5 Ring type joint groove facing ROUGHNESS shall not exceed (side wall surface of gasket 63 AARH groove) 4.6 Ring type joint contact surface minimum hardness shall not be less than: - Type Brinell 4.7 When galvanizing is specified, forged flanges shall be coated with zinc inside and outside by hot-dip process to ASTM A153 after all forming and heat treatment has been completed. 4.8 All threads on galvanized forged flanges shall be cut after galvanizing. IBR REQUIREMENTS: 4.9 Flanges coming under the purview of IBR (Indian Boiler Regulation) shall be accompanied with IBR certificate in Form-III C duly approved and countersigned by IBR authority / local authority empowered by central boiler board of India For carbon steel flanges described as "IBR" (chemical composition shall confirm to the following): Carbon (max) : 0.25 % Others (S, P, Mn) : As prescribed in IBR regulation The chemical composition as indicated in this clause is not applicable for flanges other than IBR. 5. Dimensions 5.1 Flanges shall be designed as follows: - NFS 24 and smaller : ANSI B NFS 26 to NFS 32 : API Outside diameters and wall thicknesses of pipes connected shall refer to ANSI B36.10 or ANSI B Unless otherwise specified, end connections shall be as follows: - Threaded: Internal taper pipe threads to ANSI Bl Socket welding: ANSI B16.5 Slip-on and Lapped joint - Beveled: End preparation shown on Figure 8 for wall thickness 22mm and smaller, and Figure 9 for wall thicknesses greater than 22mm in ANSI B Dimensional tolerances shall be within the limit specified in the applicable standards (ANSI/API). 6. Inspection and Tests 6.1 Inspection and tests at the Vendor's shop shall be carried out in conformance with the requirements of the material standards (ASME/ASTM) specified on the purchase order documents. 6.2 Supplementary requirements other than specified in the applicable material standards shall be in accordance with the purchase order documents. 6.3 Any flanges do not require hydrostatic testing

4 6.4 Test reports shall be supplied for all mandatory tests as per the relevant material specifications. Test reports shall also be furnished for any supplementary tests as specified in the requisition. 6.5 For ring joint flanges, blinds and spacers, the hardness shall be recorded on the test report. For ring joint flanges, blinds and spacers the hardness shall be as follows: Flange material Min. Hardness of Groove (BHN) Carbon steel 140 1% cr. to 5% Cr 150 Type 304,316, Type 304L, 316L One tension test and one bend test shall be carried out for each heat in each heat treatment charge. 6.7 Impact test for low temp service shall be carried out at the lowest design temperature and shall meet the requirements of the applicable material specifications. 6.8 Austenitic stainless steel items shall undergo Inter Granular Corrosion (IGC) test to ASTM A 262 practice 'B' and acceptance criteria shall be that the,corrosion rate shall not exceed 48 mils per year. Two sets of samples shall be drawn from each heat treatment lot, one set corresponding to highest carbon content and other set corresponding to highest rating / thk. 7.0 INSPECTION 7.1 Inspection authority means the inspection agencies approved by the Owner. Approved inspection agencies are M/s. Lloyds, TUV & BVIS Inspection Agency are approved for overseas vendors for Non-IBR items. M/s. LRIS, RW - TUV & BVIS Inspection Agency are approved for Indigenous vendors for Non-IBR items. For IBR Items, Please refer to Annexure. 7.2 Pipe flanges for steam service shall be tested in accordance with requirement of IBR and certified in IBR Form IIIC by IBR authority. 7.3 The inspecting authority shall be provided free access at all possible times to those parts of supplier s work engaged in production and testing of materials ordered. 7.4 The inspecting authority shall have the right to select random samples for check test and reject materials, if samples furnished as above and tested as per the specifications fail to meet the requirement specified. 7.5 All the items shall be inspected and tested in the presence of one or more representatives of the purchaser during various stages of manufacturing starting from identification of raw material up to completion. Material shall be considered acceptable for dispatch only after final certificate of acceptance is issued by the inspector. 7.6 Testing performed in the presence of the purchaser s representatives shall not relieve the supplier of their own responsibilities and guarantees and any other contractual obligations. 8. Marking & Preservation 8.1 Each flange shall be marked using low stress round nose stamps on the external rim of flanges in accordance with the applicable ASTM Standards and MSS SP In addition to the standard marking of the above, each flange shall be color marked with continuous stripe(s) on the outside surface to identify the material specification in the same size, particularly material type or grade. Material Basic Color ASTM A105 Not required ASTM A182 GR F11 Blue ASTM A182 GR F304 Not required - 4 -

5 ASTM A182 GR F304L Brown ASTM A182 GR F316L Green Note : a. For austenitic stainless steel, the marking paint or ink should be chloride-free and shall contain no metal or no metal salts, such as zinc, lead copper, tin which could be harmful during welding, heating or services. 8.3 All items shall be legibly and conspicuously stamped in accordance with the requirements of applicable ANSI, API and MSS standards. 8.4 All items coming under the purview of "IBR", "CRYO"&"NACE" shall be painted in red strips, light purple strips & canary yellow strips (25 mm. width) respectively for easy identification. 8.5 Paint or ink for marking shall not contain any harmful metal or metal salts such as zinc, lead or copper which causes corrosive attack on heating. 8.6 Flanges manufactured according to ANSI B 16.5, ASME B 16.47, API 605, MSS SP44 shall be marked as per code and MSS-SP-25. Schedule number of butt welding ends shall be marked. 8.7 In addition, information about heat number and heat treatment shall be indicated. Flanges manufactured to other standard shall be marked as per relevant code. If standard is silent on marking, material spec., size and pressure rating shall be marked by punching. 8.8 Rust preventive on machined surfaces to be welded shall be easily removable with a petroleum solvent, and the same shall not be harmful to welding. 8.9 Flanges covered under steam service shall be stamped/ marked as per I.B.R. In addition to above, flanges under I.B.R shall be given one band of red paint for identification After inspection and before dispatch, flanges shall be thoroughly dried and cleaned. All flanges except SS flanges shall be coated with hard film type of rust preventive to protect against rusting during transit and storage. 9. Preparation for Shipment 9.1 All products shall be thoroughly cleaned of loose scale, dirt and other foreign materials before shipment. 9.2 Each unit shall be suitably prepared for the shipment, properly braced, and secured to prevent damage during shipment. 9.3 All products shipped separately shall have suitable tagging or marking indicating material name DOCUMENTATION 10.1 The flanges shall be supplied with 3 copies of the mill test certificates indicating the following and duly signed by the inspecting authority along with supply of materials. In addition 8 copies of these certificates shall be sent to Contractor for final compilation. a) Purchase order no. b) Material test certificates (Material specification, grade, physical property, chemical composition & heat treatment report) shall also be furnished for the flanges supplied. c) Size and Sch. No. /thickness d) Quantity e) Heat and lot no. f) Results of Chemical analysis g) Mechanical test results (as per applicable Clause). h) Results of impact test where applicable. i) Non-destructive test results (as per applicable clause) 10.2 Flanges meant for steam service shall be supplied with 3 copies of I.B.R. certificates in Form IIIC duly signed by IBR inspecting authority along with supply of materials. In addition 8 copies shall be sent to Owner / Contractor for final compilation