Quality Control
Quality Assurance Plan (QAP) is the specified quality plan which should be adhered to while manufacturing a particular product.
Stages of Quality Assurance Plan (QAP) for steel bridge fabrication are mentioned hereunder in a generalised and concise manner.
1. RAW MATERIALS (Steel Structural Sections and Plates)
i ) Identification & Co-relation with Mill Test Certificate
ii) Ultrasonic Test of Plates.
iii) Tensile Test & Chemical Analysis from reputed Test House/ Laboratory.
2. WELDING CONSUMABLE (From approved vendor)
i) Verification of Supplier Test Certificate.
3. FASTENERS
i) Verification of Supplier’s Test Certificate.
ii) Physical, Mechanical & Chemical Test from reputed Test House/Laboratory
4. PAINTS
i) Verification of Supplier’s Test Certificate.
5. PQR & Welder Qualification Test
i) Preparation of Welding Procedure Specification (WPS) & its qualification by Testing & Welder Qualification Test & to form Procedure Qualification Record (PQR) Documents.
ii) Welder’s Performance qualification as per Qualified PQR.
6. MANUFACTURING PROCESS (Preparatory Work)
i) Marking, Flame cutting, Straightening, bending, drilling, machining, drilling jig & fixture & templates etc.
ii) Dimensional layout, checking of Cambered length as per approved drawing.
7. FIT UP
i) Dimensional & Alignment Checking as per approved drawing.
8. Post Weld Inspection
i) Proper welding sequence to be adopted to avoid distortion of structural components.
ii) Post welding inspecvtion involves visual & non-destructive testing (DPT, MPT, RT / UT)
9. Drilling of Holes
i) All members should be drilled preferably by drilling jigs, approved by the Inspection Agency.
10. TRIAL ASSEMBLY
i) Dimensional checking, hole matching, Checking of no-load/Dead load Camber geometry & alignment checking as per approved drawing.
11. PAINTING (Surface Preparation)
i) Sand Blasting/ Buffing
ii) Measurement of Dry Film Thickness of Paint Coating.
iii) Prominence & Correctness of Match Marking
General Remarks :
Quantum of checking, reference documents / relevance specifications & drawings, acceptance criteria, etc. should be mentioned against each of the above items as per the contract documents / specifications.