Supervision Outline for Plate and Shell Heat Exchangers

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Quality Inspection Outline for the Manufacturing Process of Plate and Shell Heat Exchangers 1. General Provisions 1.1 Scope and Applicability 1.1.1 This outline specifies the basic contents and requirements for quality inspection during the manufacturing process of plate and shell heat exchangers by the purchasing party (or user), and can also serve as a basis for entrusting on-site supervision of manufacturing. 1.1.2 This outline applies to shell and plate heat exchangers used in the petrochemical industry. 1.2 Main basis for compilation: 1.2.1 \"Regulations on Safety Technical Supervision of Pressure Vessels\" ； 1.2.2 GB 150 «Steel Pressure Vessels» ； 1.2.3 GB 151 \"Shell and Tube Heat Exchangers\" ； 1.2.4 GB 16409 \"Plate Heat Exchangers\" ； 1.2.5 GB 16749 \"Wave Expansion Joints for Pressure Vessels\" ； 1.2.6 JB 4732 \"Analysis and Design of Steel Pressure Vessels\" ； 1.2.7 Design documents for plate-shell heat exchangers and procurement “Technical Agreement” ； 1.2.8 Relevant standards, etc. 2. Raw Materials 2.1 The main steel grades for the shell are 321, 316L, 16MnR, 2.25Cr1Mo, and 1.25Cr0.5MoSi ； The main steel grades for plates are 321, 316L, TA2, and 2205. 2.2 In accordance with the procurement Technical Agreement, verify the quality certificates of the main materials (including welding materials); the material grades and specifications, the grade of the forgings, the quantity, and the supplier shall all be in line with the provisions of the procurement Technical Agreement. 2.3 The main materials shall be inspected for appearance, heat treatment condition, and material marking. 2.4 The chemical composition, temper brittleness sensitivity coefficient, mechanical properties at room temperature, mechanical properties at high temperatures, Charpy impact test results, grain size, and non-metallic inclusions (for forgings) of major pressure-bearing components such as cylinders, heads, equipment flanges, manway flanges and covers, inlet and outlet flanges and covers, and flanged connections, as well as hardness, assessment of temper brittleness tendency, intergranular corrosion tests, results of non-destructive testing and sampling locations, number of specimens, and simulated heat treatment conditions shall all be in accordance with the provisions specified in the purchased Technical Agreement. Re-inspection of materials shall be carried out in accordance with the \"Regulations on Safety Supervision of Pressure Vessels\" and the provisions of the purchased \"Technical Agreement\". 2.5 The chemical composition, mechanical properties, intergranular corrosion test, and heat treatment condition of the plates shall be in accordance with the provisions of the purchased Technical Agreement. 2.6 The material grade and specifications, chemical composition, and mechanical properties of the bellows shall be in accordance with those specified in the procurement Technical Agreement. 2.7 The material inspection for main bolts, main nuts, supports, etc. shall comply with the provisions specified in the procurement technical agreement. 2.8 Bolts manufactured from bars with Ф≥50 shall undergo ultrasonic inspection after rough machining, and be accepted in accordance with the purchased Technical Agreement. 2.9 The inspection of shell welding materials and stainless steel surfacing materials shall comply with the procurement provisions specified in the Technical Agreement. 2.10 For base materials whose heat treatment condition is altered during the manufacturing process, performance heat treatment shall be carried out again; the resulting mechanical properties shall comply with the relevant specifications for the base material. 3. Welding 3.1 Welders must hold a valid welding qualification certificate corresponding to the appropriate category. 3.2 The manufacturer shall complete the welding procedure qualification in accordance with the construction drawings, the purchased \"Technical Agreement\", and the provisions of JB4708 before welding the product. 3.3 The welding procedure qualification shall cover at least the welded joints of the base material, surfacing welded joints, welded joints of dissimilar steels, and welded joints of plate bundle materials. 3.4 The welding procedure qualification report shall be submitted to the relevant authorities for approval in accordance with the provisions of the purchased Technical Agreement. 3.5 Welding operations must strictly adhere to welding procedure specifications. 3.6 Cr-Mo steel should be preheated before welding, and hydrogen removal or stress relief treatment should be carried out promptly after welding. 3.7 The number of welding repairs shall not exceed the limits specified in the purchased Technical Agreement, and all repairs must be supported by a process qualification assessment. 3.8 Weld inspection: 3.8.1 The deposited metal of the pressure-bearing welds in Cr-Mo steel shall be subject to chemical composition testing; the number of samples taken and the analysis results shall be verified in accordance with the purchased \"Technical Agreement\". 3.8.2 The hardness testing of pressure welds (including the heat-affected zone and base metal) after final heat treatment shall be carried out in accordance with the provisions of the purchased Technical Agreement. 3.8.3 The fillet welds at the joint should be welded in the flat position whenever possible, and the height of the weld corners as well as the smoothness of the transitions should be checked. 3.8.4 The weld appearance shall not contain defects such as undercutting, cracks, pores, cratering, slag inclusions, or spatter. 3.8.5 The welding of the long sides of the plate-tube elements, the stacking of plate-tubes, the welding of inserts to the ends of plate-tubes, the welding of inserts to the long sides of plate-tubes, the welding of inserts to the compression plates, the welding of the ends of plate-tubes, and the welding of the upper and lower plate-tubes to the compression plates shall all comply with the welding procedure specifications specified in the construction drawings. Welding must be carried out continuously, without any defects such as burn-through or weak welds. 3.8.6 The welding method for the long sides of the plate tubes shall be resistance welding and TIG welding, while TIG welding shall be used for the remaining parts of the plate bundle. 3.8.7 The surfacing layer shall undergo chemical composition analysis, with the sampling locations and quantities determined in accordance with the procurement \"Technical Agreement\" for acceptance purposes. 3.8.8 The weld overlay shall be subjected to ferrite number determination. The testing methods, sampling locations, and quantities shall be subject to the acceptance criteria specified in the purchase \"Technical Agreement\". 3.8.9 The bellows of the expansion joint shall be integrally formed; ring welds are not allowed, and only one longitudinal weld is permitted. 3.8.10 The surfacing layer on the flange sealing surface shall be subjected to hardness testing, and acceptance shall be carried out in accordance with the purchased Technical Agreement. 4. Non-destructive testing 4.1 Personnel conducting non-destructive testing shall hold valid qualification certificates corresponding to the appropriate category (grade). 4.2 The ultrasonic inspection of pressure forgings after rough machining shall be carried out in accordance with the provisions of the purchased Technical Agreement for acceptance. 4.3 Magnetic particle or penetrant inspection of pressure forgings after finishing shall be carried out in accordance with the provisions of the purchased Technical Agreement for acceptance. 4.4 The shell plates shall be subject to ultrasonic inspection in accordance with standard requirements, and accepted as specified in the purchase \"Technical Agreement\". 4.5 Non-destructive testing of pressure-bearing welds: 4.5.1 The testing methods, testing proportions, and acceptance criteria for Class A, B, and D welds of the shell shall comply with the provisions specified in the purchased Technical Agreement. 4.5.2 100% radiographic inspection shall be carried out on Class A and Class B welds of Cr-Mo steel after welding, and they shall be accepted according to Grade II of JB/T4730-2005. 4.5.3 100% ultrasonic inspection shall be carried out on Class A and Class B welds of Cr-Mo steel after welding, heat treatment, and hydrostatic testing, and they shall be accepted according to Grade I of JB/T4730-2005. 4.5.4 For welds of types A, B, and D in Cr-Mo steel, 100% magnetic particle inspection shall be carried out after welding, heat treatment, and hydrostatic testing, and they shall be accepted according to grade I of JB/T4730-2005. 4.5.5 The testing methods, testing ratios, and acceptance levels for other steel grades shall comply with the provisions of the purchased Technical Agreement. Among them, for shell classes A and B with δ≥38 mm, 20% ultrasonic inspection shall be carried out after welding, and acceptance shall be conducted in accordance with JB/T4730 Grade I. 4.6 The inspection methods, inspection ratios, and acceptance levels for the connection joints between the shell and supports as well as the welded joints of the support cylinders shall comply with the provisions of the procurement “Technical Agreement”. 4.7 After welding, heat treatment, and hydrostatic testing, non-destructive inspection shall be carried out on the surfacing sections and joints where the shell is connected to the skirt, as well as on the Cr-Mo steel joints in the skirt, the joints between Cr-Mo steel and carbon steel, and the carbon steel joints. The inspection methods, inspection ratios, and acceptance criteria shall comply with the provisions of the purchased Technical Agreement. 4.8 The longitudinal seams of bellows shall undergo 100% radiographic inspection and be accepted in accordance with Grade II of GB/T 3323. 4.9 100% penetrant inspection shall be carried out on all welds of the expansion joint, and acceptance shall be conducted in accordance with JB/T4730-2005, Grade I. 4.10 100% penetrant inspection shall be carried out on all welds between the plate bundle inserts and plate tubes, between the inserts and side plates, and between the compression plates and side plates, to be accepted in accordance with JB/T4730 Grade I. 4.11 The stainless steel surfacing layer shall undergo 100% penetrant inspection and be accepted in accordance with JB/T4730 Grade I. 5. Dimension inspection 5.1 After machining or rounding, the cylinder should be inspected for its geometric shape and dimensions. 5.2 After head stamping, geometric shape and dimension checks should be performed. 5.3 Dimension inspection should be carried out after the processing is completed. 5.4 The thickness of all surfacing layers shall be inspected. 5.5 The overall dimensions, pipe outlet orientation, and protrusion height shall be inspected. 5.6 Plate bundle components: 5.6.1 The wave depth of the plates after pressing as well as the dimensions of the plates shall be inspected ； 5.6.2 After pressing, the metallographic structure of the raw material shall not be altered; the surface shall be free from scratches and indentations ； 5.6.3 During the assembly of the plate bundle and the lower housing, the slide rail of the plate bundle should be positioned at the midpoint and aligned with the load-bearing structure below; the assembly orientation shall follow the construction drawings ； 5.6.4 The side shims must not be welded to the plates ； 5.6.5 Perpendicularity of support plates, side plates, and plate bundles ； 5.6.6 The manufacturing, inspection, and acceptance of plate bundles shall be carried out in accordance with the relevant procurement technical agreement; strict control shall be exercised over the extent to which the inserts protrude beyond the dimensions of the plate sheets, the extent to which they are below the dimensions of the end seams of the plate bundle, and the gap between the inserts and the plate tubes. 5.7 The geometry and dimensions of the expansion joint shall be inspected. 5.8 The concentricity between the expansion joint, nozzles, shell, and bundle should be checked. 5.9 The size of the distribution plate and distribution pipes of the distributor shall meet the requirements of the construction drawings, and the distribution holes must be free of burrs or other obstructions. 6. Heat Treatment and Test Plates 6.1 Heat treatment of the base material: 6.1.1 After the thermal forming of the cylinder and the head, performance heat treatment shall be carried out, along with the use of test plates made from the base material ； 6.1.2 Heat treatment for bellows forming shall be carried out in accordance with relevant standards and the provisions of the purchased \"Technical Agreement\" ； 6.2 The intermediate heat treatment and dehydrogenation treatment after welding of Cr-Mo steel shall be carried out in accordance with the provisions of the purchased Technical Agreement. 6.3 Inspection before final heat treatment: 6.3.1 All welded parts and pre-welded components shall be fully welded ； 6.3.2 Visual inspections of the inner and outer surfaces shall be carried out, and all welds on the tooling must be thoroughly removed ； 6.3.3 Base metal test plates and welding test plates shall be complete ； 6.3.4 All inspections prior to the final heat treatment of the product shall have been completed. 6.4 Final heat treatment: 6.4.1 The number of thermocouples, their placement and fixation, the heat treatment temperature and holding time shall all comply with the provisions of the purchased Technical Agreement. For each main weld, it is necessary to record the number of intermediate and final heat treatments, the holding temperature, the holding time, as well as the rate of temperature rise and fall. 6.5 Test plates ； 6.5.1 The mechanical properties of the base material test plates shall comply with the provisions of the purchased Technical Agreement ； 6.5.2 The quantity of welding test plates, inspection items, and mechanical property results shall comply with the provisions of the purchased Technical Agreement and JB4744-2000. 7. Pressure testing and packaging for shipment 7.1 The hydrostatic test pressure for the plate side and shell side, the pressure holding time, water temperature, chloride content, etc., shall be in accordance with the construction drawings and the provisions of the purchase \"Technical Agreement\". 7.2 The pressure for the shell-side airtightness test, the holding time, and the acceptance criteria shall be in accordance with the relevant standards. 7.3 After the shell side, individual plate tubes, and plate bundles have been assembled, an ammonia leakage test shall be conducted. The test pressure, medium concentration, holding time, and acceptance criteria are specified in the relevant standards. 7.4 After the plate bundle is assembled, a gas-tightness test shall be conducted. The number of tests, test pressure, holding time, and acceptance criteria shall be in accordance with relevant standards. 7.5 Before welding the expansion joint assembly, a hydrostatic test shall be conducted; the test pressure, holding time, water temperature, chloride content, etc., shall comply with the provisions of the construction drawings and the purchased \"Technical Agreement\". 7.6 After the overall hydraulic test of the equipment, drying treatment is carried out. 7.7 The outer surface of the shell shall be descaled by sandblasting to meet the requirements of Sa2.5 grade as specified in GB8923. 7.8 The paint on the outer surface of the shell shall comply with the provisions of the procurement “Technical Agreement” and the construction drawings. 7.9 The acid washing and passivation of the surface of stainless steel shells shall comply with the provisions of the procurement “Technical Agreement” and the construction drawings. 7.10 All penetrations shall be at least covered and sealed with waterproof material. 7.11 The physical inspection prior to packing should be consistent with the checklist. 7.12 The shell interior shall be filled with nitrogen for protection, and the pressure shall be as specified in the purchased Technical Agreement or construction drawings. 8. Other requirements 8.1 Written consent from the owner or the engineering design unit is required for material substitutions and changes to the drawings. 8.2 Welding repairs to the main pressure-bearing forgings must be approved in writing by the owner. 8.3 Other special requirements shall be implemented in accordance with the provisions of the procurement Technical Agreement. 9. Key control points for on-site supervision during the manufacture of plate-and-shell heat exchangers
No. | Component/Process Name | Supervision contents | Documentary evidence points (R) | On-site witnessing/inspection points (W/S) | Hold points (H)
---|---|---|---|---|---
1 | Shell sections | 1. Review of material quality certificates R
2. Chemical composition (smelting analysis, product analysis) R
3. Sensitivity coefficients X and J for temper brittleness (for Cr-Mo steel) R
4. Mechanical properties (at room temperature and high temperatures) R
5. Intergranular corrosion test (for stainless steel) R
6. Evaluation of temper embrittlement tendency (for 2.25Cr1Mo material) R
7. Grain size (for forgings) R
8. Non-metallic inclusions (for forgings) R
9. Ultrasonic testing R
10. Magnetic particle inspection of weld grooves (for Cr-Mo steel) R
11. Hardness at pre-bent areas (for Cr-Mo steel), roll forming, longitudinal seam welding, and intermediate heat treatment inspection R W
12. Roundness correction and geometric shape inspection (roundness, angularity) R W
13. Appearance and non-destructive testing of longitudinal seams (RT, UT, MT) R W
14. Chemical composition analysis of deposited metal in longitudinal seams (for Cr-Mo steel) R
2 | Head | 1. Review of material quality certificates R
2. Chemical composition (smelting analysis, product analysis) R
3. Sensitivity coefficients X and J for temper brittleness (for Cr-Mo steel) R
4. Mechanical properties (at room temperature and high temperatures) R
5. Intergranular corrosion test (for stainless steel) R
6. Evaluation of temper embrittlement tendency (for 2.25Cr1Mo material) R
7. Grain size (for forgings) R
8. Non-metallic inclusions (for forgings) R
9. Ultrasonic testing R
10. Magnetic particle inspection of weld grooves (for Cr-Mo steel) R
11. Shape and geometric dimensions after stamping (roundness, diameter, thickness) R W
12. Post-stamping heat treatment and mechanical property testing of base material test plates R
13. Non-destructive testing after stamping (UT, MT) R W
14. Dimensional inspection after finish machining W
3 | Equipment flanges, support plates, manhole flanges and covers, inlet/outlet flanges | 1. Review of material quality certificates R
2. Chemical composition (smelting analysis, product analysis) R
3. Sensitivity coefficients X and J for temper brittleness (for Cr-Mo steel) R
4. Mechanical properties (at room temperature and high temperatures) R
5. Intergranular corrosion test (for stainless steel) R
6. Evaluation of temper embrittlement tendency (for 2.25Cr1Mo material) R
7. Grain size (for forgings) R
8. Non-metallic inclusions (for forgings) R
9. Ultrasonic testing R
10. Dimensional inspection after finish machining R S
11. Magnetic particle inspection of machined surfaces (for Cr-Mo steel) R
12. Inspection of thickness of stainless steel cladding layer on flanges R S
13. Non-destructive testing of cladding layer (PT) R
14. Hardness inspection of sealing surface of cladding layer R W/S
4 | Plate bundle | 1. Review of plate quality certificates, including chemical composition, mechanical properties, and intergranular corrosion test R
2. Inspection of plate geometric dimensions and appearance S
3. Inspection of assembly dimensions and appearance of plate bundle W
4. Ammonia leakage test for individual tubes R W/S
5. Ammonia leakage test for TIG-welded end seams R W/S
6. Ammonia leakage test for plate passages of plate bundle R W/S
7. Hydrostatic test for plate passages of plate bundle R H
5 | Distributor | Dimensional and appearance inspection W
6 | Expansion joint | 1. Review of material quality certificates, including chemical composition, mechanical properties, non-destructive testing of welds (RT, PT), and heat treatment reports R
2. Concentricity and geometric dimension inspection R W
3. Hydrostatic test R W
7 | Main bolts | 1. Review of material quality certificates, including chemical composition, mechanical properties, and non-destructive testing of welds (UT, MT) R
2. Dimensional and precision inspection S
8 | Main nuts | 1. Review of material quality certificates, including chemical composition and hardness inspection R
2. Dimensional and precision inspection R S
3. Non-destructive testing after finish machining (MT) R
4. Load-bearing test (as specified in the procurement Technical Agreement) R
9 | Supports | 1. Inspection of material quality certificates R
2. MT, UT, RT inspections for longitudinal and circumferential welds of Cr-Mo steel shell sections R
3. RT inspections for longitudinal and circumferential welds of carbon steel shell sections R
4. MT and UT inspections for cladding areas where skirt and shell are joined R
10 | Final assembly | 1. RT inspections for Class A/B welds of shell R
2. MT/PT and UT inspections for Class A/B/D welds of shell R
3. Chemical composition inspection of deposited metal in Class A/B/D welds of Cr-Mo steel R
4. PT/MT inspections for cladding layer R
5. Determination of ferrite content in cladding layer (if required) R
6. Chemical composition of cladding layer (if required) R
7. Straightness of shell and misalignment inspection of circumferential seams W
8. Orientation and dimensional inspection of nozzles W
9. Appearance inspection of inner and outer surfaces of equipment W
10. Concentricity inspection between plate bundle, expansion joint, and shell W
11. Assembly dimension inspection between distributor, fully welded plate bundle, and shell W
12. Perpendicularity inspection between support plates and plate bundle W
13. PT inspection for sealing welds between equipment flanges and support plates W
14. Dimension and appearance inspection of fillet weld angles W
15. Post-weld MT inspection for welds joining supports to shell R
11 | Heat treatment | 1. Intermediate heat treatment inspection for Class A/B/D welds of Cr-Mo steel R
2. Overall final heat treatment or sectional heat treatment inspection R W
3. Hardness inspection after final heat treatment for Class A/B/D welds of Cr-Mo steel R W
4. MT and UT inspections after final heat treatment for Class A/B/D welds of Cr-Mo steel R
5. MT and UT inspections after final heat treatment for welds joining supports to shell and butt welds of support shell sections R
6. MT/PT inspections after final heat treatment at locations where temporary connections were removed R
7. PT inspection after final heat treatment for stainless steel cladding layer R W/S
12 | Test plates | 1. Inspection of base material performance test plates after heat treatment R
2. Inspection of product welding test plates R
13 | Pressure tests | 1. Airtightness test for plate passages R W/S
2. Airtightness test for shell passages R W
3. Ammonia leakage test for plate passages R W/S
4. Ammonia leakage test for shell passages R W
5. Hydrostatic test for plate passages R H
6. Hydrostatic test for shell passages R H
7. Overall hydrostatic test for equipment R H
8. UT inspection after hydrostatic test for Class A/B welds of Cr-Mo steel R
9. MT inspection after hydrostatic test for Class A/B/D welds of Cr-Mo steel R
10. MT and UT inspections after hydrostatic test for welds joining Cr-Mo steel supports to shell R
11. Appearance and internal cleanliness inspection W
12. Drying treatment must be performed after overall hydrostatic test of equipment W
14 | Other purchased parts | 1. Inspection of gasket certificates of conformity R
2. Random inspection of gasket geometric dimensions and appearance W/S
15 | Factory inspection | 1. Appearance inspection of flange sealing surfaces W
2. Inspection of sandblasting, rust removal, and painting W
3. Inspection of stainless steel pickling W
4. Inspection of nozzle packaging W
5. Inspection of markings W
6. Inspection of nitrogen purging protection W