Quality Assurance

Quality Assurance
QA Department Introduction
  • Quality inspection and management throughout the manufacturing process of plate heat exchangers, heat transfer compact units, plate & shell heat exchangers, non-pressure vessels and other thermal equipment

    The department ensures that products comply with applicable regulations, industry standards, contract requirements, and customer specifications.

  • Responsible to coordinate, manage, and maintain the operation of various certification systems.
Inspection process for plate heat exchangers and heat transfer compact units
Inspection process for plate heat exchangers and heat transfer compact units
  • Inspection records
  • Material inspection: Heat transfer plates, Gaskets
  • Process inspection: Machining, Mechanical processing, Sand blasting, Painting., Assembly, Welding, Pressure testing, Nameplate & product identification, Insulation, Electrical control cabinet, Packaging
Inspection Standards & Criteria
  • Quality assurance system for plate heat exchanger safety registration
  • ISO 9001 Quality Management System
  • ISO 3834 Welding Quality Management System
  • Contract requirements and customer specifications
  • National and industry standards
  • ISO 14001:2015 Quality Management System CertificationISO 14001:2015 Quality Management System Certification
  • ISO 9001:2015 Quality Management System CertificationISO 9001:2015 Quality Management System Certification
  • ISO 3834 International Welding Quality CertificationISO 3834 International Welding Quality Certification
  • British PD 5500 Pressure Vessel CertificationBritish PD 5500 Pressure Vessel Certification
  • PED (Pressure Equipment Directive) CertificationPED (Pressure Equipment Directive) Certification
Material Inspection
    • Heat Transfer Plates Material Inspection
      Heat Transfer Plates Material Inspection
    • Heat Transfer Plates Thickness Inspection
      Heat Transfer Plates Thickness Inspection

      Standard: NB/T 47004-2009

    • Heat Transfer Plates Dye Penetrant Testing
      Heat Transfer Plates Dye Penetrant Testing
      • Cleaning agent
      • Penetrant
      • Developer
    • Heat Transfer Plates Hardness Test
      Heat Transfer Plates Hardness Test
      • NBR: 73 ± 5
      • EPDM: 80 ± 5
      • Inspection Standard: NB/T 47004-2009
Process Inspection
Machining
    • Machining

      Inspect frame dimensions according to the plate frame drawings.

    • Machining

      Inspect frame dimensions according to the plate frame drawings.

Fitting & Assembly Preparation
    • Fitting & Assembly Preparation

      Inspect flange drilling dimensions.

    • Fitting & Assembly Preparation

      Inspect plate frame drilling dimensions.

Sand Blasting
    • Sand Blasting

      Before sand blasting, verify the accuracy of transferred identification markings.

    • Sand Blasting

      After sand blasting, inspect the frame surface for oil contamination, rust, oxidation layers, and exposed metal surfaces.

Painting
    • Painting

      Operators complete the painting process according to the standard plate frame manufacturing procedure and perform self-inspection. (Reference sample shown in the image)

    • Painting

      Inspect coating thickness using a coating thickness gauge. Compare with reference samples to check color difference, coating wrinkles, and adhesion performance.

Assembly
    • Assembly

      Confirm the gasket material of installed heat transfer plates before assembly.

    • Assembly

      Inspect plate installation quality and production number marking transfer.

Welding
    • Welding

      Inspect weld quality using reference samples, including weld height & width and pipe verticality and parallelism.
      The weld surface shall be free from cracks, incomplete penetration, lack of fusion, surface pores, arc craters, incomplete filling, slag inclusions, and welding spatter. The weld shall have a smooth transition with the base material, and the profile of fillet welds shall have a smooth concave transition.

    • Welding

      Inspect installation quality of packaged heat exchange units.

Pressure Testing
    • Pressure Testing

      Inspect the sealing surfaces of plate heat exchangers.

    • Pressure Testing
      • Inspect pipe welding positions, threaded connections, and flange connection points.
      • Test pressure: PT = 1.3P
      • Plate Heat Exchanger holding time: 45 minutes per side
      • Packaged Heat Exchanger Unit holding time: 120 minutes
      • Inspection Standard: NB/T 47004-2009
Nameplate & Identification
    • Pressure Testing

      late heat exchanger nameplate, inlet and outlet markings, model identification

    • Pressure Testing

      Heat transfer compact unit nameplate, model identification, inlet and outlet markings

Insulation
    • Insulation
      • Insulation material selection
      • Insulation thickness
      • Insulation appearance quality
Electrical Control Cabinet
    • Electrical Control Cabinet

      Inspection of electrical drawings and component models

    • Electrical Control Cabinet

      Inspection of control programs and remote signal functions

Packaging
    • Packaging

      Packaging for plate heat exchangers

    • Packaging

      Packaging for heat transfer compact unit

Inspection Process for Plate Heat Exchangers & Non-Pressure Vessels
Inspection Process for Plate Heat Exchangers & Non-Pressure Vessels Inspection Standards & Criteria
  • Quality assurances system for special equipment manufacturing license
  • ISO 9001:2008 Quality Management System
  • ISO 3834 Welding Quality Assurance System
  • Contract requirements and customer specifications
  • National standards and industry standards
Material Inspection
Head
    • Head
      • Surface quality inspection
      • Material inspection
    • Head

      Thickness measurement

    • Head

      Roundness measurement

    • Head

      Circumference and inner diameter measurement

Plates
    • Plates
      • Appearance inspection
      • Diagonal dimension measurement
      • Length and width measurement
    • Plates

      Thickness measurement

    • Material Inspection

      Material inspection (identification reagent testing and periodic external inspection)

Seamless Steel Pipes
  • Appearance inspection
  • Material inspection: Steel pipe material verification using identification reagent testing
  • Out-of-roundness inspection
  • Outer diameter inspection
  • Standard steel pipe thickness inspection
Flanges
Flanges
  • Flange material inspection
  • Flange dimension inspection
Process Inspection
Cutting
Cutting

Measure the size and position of all openings, as well as plate dimensions.

Requirements:

  • The deviation of the distance between adjacent hole centres and the displacement of hole centres shall not exceed ±0.5 mm. The cumulative deviation shall not exceed ±2 mm.
  • The allowable diagonal deviation of the cut plate shall not exceed 2 mm.
Rolling
Rolling

Inspect cylinder section ovality.

Rolling
  • Inspect cylinder section misalignment.
  • Cylinder section misalignment: A ≤ T (plate thickness) and shall not exceed 10 mm.
Longitudinal Weld

The weld surface shall be free from cracks, incomplete penetration, lack of fusion, surface pores, arc craters, incomplete filling, slag inclusions, and welding spatter. The weld shall have a smooth transition with the base material.

    • Longitudinal Weld

      Inner diameter inspection: The difference between the maximum and minimum inner diameters on the same cross-section of the shell (e) shall not exceed 1% of the designed inner diameter Di and shall not exceed 25 mm.

    • Longitudinal Weld
      • Weld reinforcement height:
      • Inner surface: e ≤ 0–1.5 mm
      • Outer surface: e ≤ 0–4 mm
    • Longitudinal Weld

      Weld joint misalignment shall be ≤ 1/4 δs (plate thickness).

    • Longitudinal Weld

      Angular distortion E shall not exceed (δs / 10 + 2) mm and shall not exceed 5 mm.

Circumferential Weld

The weld surface shall be free from cracks, incomplete penetration, lack of fusion, surface pores, arc craters, incomplete filling, slag inclusions, and welding spatter. The weld shall have a smooth transition with the base material.

    • Longitudinal Weld
      • Weld reinforcement height:
      • Inner surface: e ≤ 0–1.5 mm
      • Outer surface: e ≤ 0–4 mm
    • Longitudinal Weld

      Angular distortion E shall not exceed (δs / 10 + 2) mm and shall not exceed 5 mm.

    • Longitudinal Weld

      Weld joint misalignment shall be ≤ 1/4 δs (plate thickness).

Fillet Weld
  • The weld surface shall be free from cracks, incomplete penetration, lack of fusion, surface pores, arc craters, incomplete filling, slag inclusions, and welding spatter. Fillet weld profiles shall have a smooth concave transition.
  • Fillet weld size inspection: K ≥ 1/2 δs and shall not be less than 6 mm.
  • When no requirement is specified in the drawing, the weld leg size shall be based on the thickness of the thinner material.
    • Fillet Weld

      Inspection method

    • Fillet Weld

      Drawing requirements

Nozzle & Flange
    • Nozzle & Flange

      Inspect perpendicularity between the nozzle and cylinder body.

    • Nozzle & Flange

      Inspect flange bolt holes, orientation, and diameter.

Pickling & Passivation
  • Weld areas shall be cleaned to expose the original stainless-steel surface.
  • Internal and external surfaces of the vessel shall be free from dirt, rust, and welding discoloration.
    • Pickling & Passivation

      Before pickling and passivation

    • Pickling & Passivation

      After pickling and passivation

Hydrostatic Test & Helium Leak Test
    • Hydrostatic Test & Helium Leak Test
      Hydrostatic Test:
      • Verify whether the pressure gauge selection is appropriate.
      • Inspect all welds and connection points.
    • Hydrostatic Test & Helium Leak Test

      Helium Leak Test: Inspect IPS welded areas.

Packaging
    • Packaging
      • Verify nameplate information
      • IPS + water tank before packaging
    • Packaging

      IPS after packaging

    • Packaging
      • Project name identification marking
      • IPS + water tank after packaging