1. General Provisions

1.1 Overview

This technical specification stipulates the manufacturing, inspection and production technical requirements for WPB and A105 pipe fittings purchased by Hebei Renlong Pipe Fittings Co., Ltd.

1.2 Units of Measurement and Language

The units of measurement adopted in this technical specification and relevant documents are general measurement units, and the language used is Chinese.

1.3 Scope of Application

This technical specification is applicable to the manufacturing, inspection and acceptance of WPB and A105 pipe fittings.

2. Scope of Supply

3. Standards and Specifications for Manufacturing and Inspection

ASME B31.1 Power Piping Code
ASTM A106/A106M Seamless Carbon Steel Pipe for High-Temperature Service
ASTM A105 Carbon Steel Forgings for Piping Components
ASTM A516/A516M Carbon Steel Plates for Pressure Vessels for Moderate and Low-Temperature Service
ASTM A234/A234M Wrought Carbon Steel and Alloy Steel Pipe Fittings for Moderate and High-Temperature Service
ASME B16.9 Factory-Made Wrought Steel Butt-Welding Fittings
ASME B16.11 Forged Steel Socket-Welding and Threaded Fittings
MSS SP-97 Integrally Reinforced Forged Branch Outlet Fittings
ASME B16.25 Butt-Welding Ends
ASTM E709 Standard Guide for Magnetic Particle Testing
ASME VIII UW–51 Radiographic Examination and Evaluation
ASTM A370/A370M Standard Test Methods and Definitions for Mechanical Testing of Steel Products

4. Raw Material Requirements for Pipe Fitting Manufacturing

4.1 Principles for Raw Material Selection

(1) ASTM A106 GRB seamless steel pipes shall be selected as raw materials for manufacturing ASTM A234-WPB-S seamless pipe fittings;
ASTM A516 GR65 steel plates shall be adopted as raw materials for manufacturing ASTM A234-WPB-W welded pipe fittings.
(2) ASTM A105 billets shall be used for the production of ASTM A105 pipe fittings.

4.2 Material Procurement

(1) Carbon steel raw materials shall be purchased from manufacturers including Pangang Group Chengdu Iron & Steel Co., Ltd., Baoshan Iron & Steel Co., Ltd., Tianjin Pipe Corporation, Shougang Group, Taiyuan Iron & Steel Co., Ltd., etc.
(2) Materials shall be purchased in accordance with ASTM standards unless otherwise specified. If domestic grade materials are selected, prior consent from the tenderer shall be obtained.

4.3 Technical Requirements for Materials

(1) The quality of raw materials shall comply with the standard requirements for materials of corresponding grades of tendered pipe fittings, and raw material procurement shall be carried out in accordance with the provisions of the bidding documents.
(2) All materials used for pipe fitting production shall be new materials with clean surfaces and free of defects.
(3) The tenderer shall provide the original or copied quality certificates issued by the raw material manufacturers of origin. Copied certificates shall be affixed with the quality inspection seal of the pipe fitting manufacturer.
(4) After raw materials are delivered to the factory, sampling re-inspection on chemical composition, mechanical properties and other indicators shall be conducted in accordance with material standards. Only qualified raw materials after re-inspection can be put into production.

5. Manufacturing and Inspection

WPB and A105 pipe fittings shall be manufactured, inspected and accepted in accordance with ASTM A234/A234M, ASTM A105, ASME B16.9, ASME B16.11 and MSS SP-97 standards.

5.1 Manufacturing Technical Requirements

Steel pipes and steel plates used as raw materials for pipe fittings shall adopt wall thickness with positive tolerance.

5.1.1 Forming Methods

(1) Carbon steel seamless elbows shall be formed by medium-frequency hot pushing with medium-frequency induction heating.
(2) Carbon steel welded elbows shall be fabricated by pressing steel plates into two half-shells followed by assembly and welding.
(3) Carbon steel seamless tees shall adopt hot drawing forming process with electric furnace heating.
(4) Carbon steel welded tees shall be made by rolling and welding steel plates into steel pipes and then hot drawing for forming.
(5) Carbon steel seamless reducers shall be hot pressed and formed with electric furnace heating.
(6) Carbon steel welded reducers shall be manufactured by rolling and welding steel plates into steel pipes followed by die pressing forming.
(7) All pipe caps shall be die-pressed from steel plates.
(8) Socket fittings and branch outlets shall be forged and formed from billets.
(9) Shielded Metal Arc Welding (SMAW) shall be applied for all welded pipe fittings. Prior to welding, the Welding Procedure Specification (WPS) and Procedure Qualification Record (PQR) covering all welded pipe fittings of corresponding materials shall be submitted to the buyer.

5.1.2 Heat Treatment

(1) Heat treatment method for WPB-S seamless pipe fittings: Normalizing at 890℃～920℃ with air cooling. The holding time shall be determined by 2.5min per millimeter of wall thickness and shall not be less than 30 minutes.
Heat treatment method for WPB-W welded pipe fittings: Post-weld stress relief heat treatment at 595℃～675℃ with air cooling. The holding time shall be determined by 5min per millimeter of wall thickness and shall not be less than 45 minutes.
(2) Heat treatment method for A105 pipe fittings: Normalizing at 890℃～920℃ with air cooling. The holding time shall be determined by 2.5min per millimeter of wall thickness and shall not be less than 45 minutes.
(3) Electric furnaces shall be used for heat treatment. Temperature measuring devices shall be calibrated and within valid verification period. Temperature record curves shall be generated during heat treatment, and heat treatment reports together with heating temperature curve records shall be provided.

5.1.3 Machining and Structural Dimensions of Pipe Fittings

End groove machining of pipe fittings shall be completed by mechanical processing in compliance with standard requirements. Structural dimensions, tolerances and connection types shall meet the specifications of ASME B16.9, ASME B16.11 and MSS SP-97.

5.1.4 Surface Treatment

For all ASME B16.9 pipe fittings, internal and external surface defects and oxides shall be removed by grinding, followed by shot blasting for rust removal. The surface cleanliness after shot blasting shall reach Sa2.5 grade. Two coats of inorganic zinc-rich primer shall be applied with a total coating thickness of 75 microns.

5.1.5 Weld Repair

Weld repair on pipe fitting bodies is prohibited without the owner’s approval. If weld repair is necessary, a dedicated repair procedure shall be formulated and submitted to the owner for approval before implementation.

5.2 Inspection

5.2.1 Surface Quality

Each pipe fitting shall undergo visual surface inspection. The internal and external surfaces of finished pipe fittings shall be free from strength and appearance impairing defects such as cracks, pits and folds. Scabs, cracks, folds and inclusions with a depth no more than 10% of the design wall thickness and not penetrating the thinner wall section shall be removed by grinding. The remaining wall thickness after defect elimination shall not be less than 90% of the nominal wall thickness; otherwise, the pipe fitting shall be scrapped.

5.2.2 Dimensional Inspection

(1) The appearance and dimensions of each pipe fitting shall be inspected one by one in accordance with ASME B16.9, ASTM B16.11 and MSS SP-97. Mechanical dimensions and dimensional deviations shall conform to relevant standards and all deviations shall be recorded in inspection reports.
(2) Wall thickness: Measured piece by piece via ultrasonic thickness gauge with a permissible deviation of ±10%. All wall thickness measurement results shall be documented in inspection reports.

5.2.3 Hardness Testing

One sample from each batch of pipe fittings shall be selected for hardness test. Hardness requirements: HB≤197 for WPB pipe fittings and 137≤HB≤187 for A105 pipe fittings. Test results shall be recorded in inspection reports.

5.2.4 Non-Destructive Testing

(1) 100% magnetic particle testing shall be performed on all carbon steel pipe fittings in accordance with ASTM E709. The testing scope covers grooves and internal and external surfaces within 100mm of pipe ends. Products with surfaces meeting standard requirements are deemed qualified.
(2) On the basis of the above testing, 100% radiographic testing shall be conducted on all welded pipe fittings per ASME VIII UW–51. Welds complying with standard specifications are considered qualified.

5.2.5 Tensile Properties of Finished Products

The tensile properties of finished pipe fittings shall satisfy the requirements of corresponding material grades.
One finished pipe fitting from each batch (products with the same raw material heat number and heat treatment batch number are defined as one batch, or furnace samples with identical processing techniques can be adopted as representatives) shall be sampled for mechanical performance tests in accordance with ASTM A370. Test reports shall be issued with performance indicators complying with corresponding material grade standards.

5.3 Other Requirements

Durable markings shall be stamped on prominent positions of finished pipe fittings as required by relevant product standards, including:
(1) Product name or code; (2) Nominal diameter and wall thickness grade;
(3) Material grade and material heat number; (4) Product standard;
(5) Item code; (6) Manufacturer code: XY

6. Protection

6.1 Anti-Corrosion

All ASME B16.9 carbon steel pipe fittings shall be treated with shot blasting to achieve Sa2.5 surface cleanliness, followed by surface blowing with dry compressed air. Two coats of inorganic zinc-rich primer shall be painted on pipe fitting surfaces with a total film thickness of 75 microns.

6.2 Protection

Moisture-proof and anti-collision measures shall be taken for pipe fittings during manufacturing and transportation.

7. Packaging and Transportation

7.1 Packaging

(1) Pipe fitting packaging shall meet the requirements of moisture resistance, rain proofing and collision prevention.
(2) Shipping marks shall comply with relevant provisions of bidding documents. The seller shall be responsible for labeling transportation packages with consignee address, cargo name, origin and destination, lifting positions, as well as the name, specification, part number and material of each component.
(3) Each package shall be equipped with packing list, certificate of conformity and quality certificate. These documents shall be sealed in plastic bags and fixed on the inner side of packaging boxes, and each package shall have a unique package number.

7.2 Transportation

Road truck transportation shall be adopted for delivery to the location designated by the buyer.

8. Document Delivery

8.1 Product Certificate of Conformity

Two copies of A4-sized certificates of conformity for qualified pipe fittings shall be submitted to the buyer, with each page affixed with the special quality inspection seal of the seller. Copies of raw material quality certificates shall bear the official red quality inspection seal of the seller. The certificate of conformity shall include the following contents:
(1) Factory inspection reports (including inspection and test reports, heat treatment reports, non-destructive testing reports and product inspection reports);
(2) Raw material inspection reports (including raw material quality certificates and re-inspection reports);
(3) Product quality certificate of conformity.

8.2 Packing List

Five days prior to delivery (on the shipping day), packing lists in compliance with the buyer’s format shall be faxed to the contract handler and consignee of the buyer respectively, and complete receipt shall be confirmed by phone. Two A4-sized copies of packing lists shall be delivered together with the goods.

9. Overall Quality Control Plan and Quality Assurance

9.1 Quality Control

(1) In the manufacturing process of pipe fittings, product design, production, inspection and testing shall be strictly implemented in accordance with relevant technical standards, specifications and the seller’s internal quality control procedures to ensure full-process controllability.
(2) Prior to the commencement of pipe fitting manufacturing, a quality plan shall be formulated based on relevant product standards and implemented as scheduled.
(3) Process specifications shall be strictly enforced during production. Product marking and marking transplantation shall be properly managed to avoid product confusion.
(4) Inspection and testing of pipe fittings shall be carried out in accordance with standards and specifications specified in bidding documents, with complete inspection records and reports archived. When necessary, the buyer shall be invited to conduct on-site inspection on designated testing items during production.
(5) Except for witness test items specified in the appendix of the purchase contract, the buyer or third-party quality supervision and inspection representatives shall be allowed to conduct on-site inspection throughout the manufacturing process. The seller shall provide all drawings, relevant standards, specifications, inspection tools and equipment to facilitate supervision and inspection.
(6) If witness tests are required by the contract appendix, the seller shall notify the buyer at least one week in advance after confirming the test date to ensure the buyer’s timely participation.

9.2 Quality Assurance

9.2.1

The seller shall guarantee that the supplied goods fully comply with the inquiry documents, drawings, technical agreements and standard requirements specified in the bidding documents, and product performance shall meet the provisions of relevant product quality standards.