Regarding valve inspection and supervision during manufacturing

Depending on the importance of the valve application, it is possible to choose on-site supervision throughout the process; however, disassembling the finished product for inspection is not recommended. Repeated disassembly and assembly affect the performance of the valve.

So it’s a bit difficult to follow those strict regulations, but in the chemical industry, the safety performance of valves is of great importance; this requires confirmation via the signature of the manufacturer. That’s why I’m asking for everyone’s opinions on this matter – after all, it’s the first time for our factory to have the valves manufactured by an external manufacturer

So it’s a bit difficult to follow those strict regulations, but in the chemical industry, the safety performance of valves is of great importance; this requires confirmation via the signature of the manufacturer. That’s why I’m asking for everyone’s opinions on this matter – after all, it’s the first time for our factory to have the valves manufactured by an external manufacturer

We are also very troubled by this issue here

You can ask the manufacturer to inform you so that you can be present during the valve assembly stage. It’s quite fast to assemble for testing!

Are you referring to a new valve or maintenance?

High-pressure lubricating oil hydrogenation project – Inspection and manufacturing requirements for low-pressure valves: 7 Inspection and testing 7.1 If the inspection and testing requirements specified by the manufacturer are stricter than those of the current relevant standards, the scope and acceptance criteria specified in the manufacturer’s standards shall be followed. The buyer reserves the right to witness on-site inspections at the manufacturing plant (including inspection records and reports of raw materials, etc.). The seller shall notify the buyer 8 weeks prior to the inspection and testing, and provide a detailed schedule including dates, times, and progress. The buyer may send representatives to the place of manufacture to participate in the tests, and the seller shall provide convenience for the work and transportation of the buyer’s representatives. 7.2 The buyer may conduct visual and physical inspections of one or all valves to ensure that the materials meet the requirements of the original purchase order and any subsequent change orders. 7.3 The seller shall conduct seat leakage tests in accordance with the procedures specified in ANSI B16.104/FCI 70.2. 7.4 The hydrostatic test shall comply with the requirements specified in API598; after the test, the water must be drained completely and the area dried using dry air. 7.5 Non-destructive testing shall be carried out in accordance with the requirements of Volume 8 of ANSI 16.34. 7.6 Valve Function Testing 7.6.1 After the valve is fully assembled, a comprehensive test of all its control and protection functions should be conducted. 7.6.2 The stroke time of all valves with specified stroke times should be checked at the specified air pressure. 7.6.3 Check whether the valve can be fully opened/closed using a handwheel. 7.7 Material Inspection and Testing 7.7.1 All materials shall meet the requirements of the relevant ASTM standards. 7.7.2 Forged parts 7.7.2.1 For carbon steel, electric furnaces combined with VOD or better methods should be used for smelting ； Austenitic stainless steels should be smelted using an electric furnace with AOD or a better method. The contents of harmful impurity elements sulfur and phosphorus should each be less than 0.02%. 7.7.2.2 For carbon steel forgings, normalizing heat treatment shall be carried out after forging ； For alloy steel forgings, normalizing followed by tempering treatment should be carried out after forging ； For austenitic stainless steel forgings, solutionizing + stabilizing heat treatment should be carried out after forging. 7.7.2.3 For each batch of forgings (i.e., those with the same batch number, material, specifications, furnace number, and heat treatment conditions), chemical composition and mechanical property tests shall be conducted at least once; the test results must meet the requirements of ASTM standards. 7.7.2.4 For each batch of forgings, metallographic structure and etching tests shall be conducted at least once; these tests shall be carried out in accordance with ASTM E381 standard. The results shall meet the following requirements: (1) For carbon steel and alloy steel, the grain size shall be no lower than grade 5 as specified in ASTM E112 standard ； For stainless steel, it should meet grade 7 as specified in ASTM E112 standard; when the thickness of the stainless steel forging exceeds 100 mm, it is also permissible to classify it as grade 6 or higher. (2) There shall be no dendritic or columnar structures. (3) Non-metallic inclusions shall meet the requirements of ASTM E45 standard: sulfides ≤ grade 1.5, silicates ≤ grade 2.5, alumina ≤ grade 2.5, spheroidized oxides ≤ grade 3; the total number of grades shall be ≤ 8.5. (4) Segregations and band-like structural irregularities larger than grade 2.5 as specified in the E45 standard are not allowed. (5) Striated inclusions and cracks are not allowed. The test specimens should be selected from areas with relatively harsh conditions, such as regions with sudden shape changes. If the inspection results do not meet any of the above conditions, the number of samples to be inspected should be doubled ； If they still fail the inspection, that batch of forgings should be re-heat-treated or discarded. 7.7.2.5 Visual inspections shall be carried out on each individual piece, and shall meet the following requirements: (1) Defects such as scars, cracks, folds, and inclusions that are no deeper than 10% of the designed wall thickness and do not extend into the minimum wall thickness may be removed by grinding; the wall thickness remaining after these defects are removed shall not be less than the minimum wall thickness. Otherwise, the forging should be scrapped. (2) Grinding removal is only permitted for microcracks with a depth not exceeding 0.8 mm ； If the depth of the microcracks is greater than 0.8 mm, the forging should be scrapped. 7.7.2.6 The inspection results shall meet the following requirements: (1) The size of a single defect shall not exceed an equivalent diameter of φ3 mm (φl mm for valve stems). (2) No dense defects; within a volume of 50 cm3, the equivalent diameter ≥ φ3 mm, with no more than 5 echoes. 7.7.2.7 The welded ends and stress concentration areas of carbon steel forged pressure components shall be subjected to magnetic particle inspection on a piece-by-piece basis, in accordance with ASTM A275 standards. The inspection results shall meet the following requirements: (1) There shall be no cracks or white spots. (2) The length of any linear display shall not exceed 2 mm. (3) The size of a single circular defect shall not exceed 3 mm. (4) The cumulative length of defects in any 100mm×100mm area shall not exceed 2mm. 7.7.2.8 The welded ends and stress concentration areas of stainless steel forged pressure components shall be subject to liquid penetrant inspection on a piece-by-piece basis, in accordance with ASTM E165 standards. The inspection results shall meet the following requirements: (1) There shall be no cracks or white spots. (2) The length of any linear display shall not exceed 2 mm. (3) The size of a single circular defect shall not exceed 3 mm (1 mm for valve stems). (4) The cumulative length of defects shall not exceed 2 mm in any area of 100 mm × 100 mm. 7.7.2.9 Defects in any pressure-bearing component shall not be repaired by welding. 7.7.3 Castings 7.7.3.1 For carbon steel, electric furnaces combined with VOD or better methods should be used for smelting ； Austenitic stainless steels should be smelted using an electric furnace with AOD or a better method. The contents of harmful impurity elements sulfur and phosphorus should each be less than 0.02%. 7.7.3.2 For carbon steel castings, normalizing heat treatment shall be carried out after casting ； For alloy steel castings, normalizing plus tempering heat treatment should be carried out after casting ； For austenitic stainless steel castings, solutionizing + stabilizing heat treatment should be carried out after casting. 7.7.3.3 For each batch of castings (i.e., those with the same batch number, material, specifications, furnace number, and heat treatment conditions), chemical composition and mechanical property tests shall be conducted at least once; the test results must meet the requirements of ASTM standards. 7.7.3.4 For each batch of castings, the metallographic structure and etching test shall be conducted at least once, with the tests being carried out in accordance with ASTM E381 standards. The results shall meet the following requirements: (1) No dendrites or columnar structure. (2) Non-metallic inclusions shall meet the requirements of ASTM E45 standard: sulfides ≤ grade 1.5, silicates ≤ grade 2.5, alumina ≤ grade 2.5, spheroidized oxides ≤ grade 3; the total number of grades shall be ≤ 8.5. (3) Segregations and band-like structural irregularities larger than grade 2.5 as specified in the E45 standard are not allowed. (4) Striped inclusions and cracks are not allowed. The test specimens should be selected from areas with relatively harsh conditions, such as regions with sudden shape changes. If the inspection results do not meet any of the above conditions, the number of samples to be inspected should be doubled ； If they still fail to meet the standards, that batch of castings should be re-heat-treated or discarded. 7.7.3.5 Visual inspections shall be carried out on each individual piece, and the acceptance criteria shall not be lower than the requirements of Grade B in MSS SP-55: (1) For defects such as scars, cracks, folds, and inclusions that do not extend into the minimum wall thickness, it is permissible to remove them by grinding; the wall thickness remaining after these defects are removed must not be less than the minimum wall thickness. Otherwise, the casting should be scrapped. (2) Grinding to remove microcracks detected by MT and PT with a depth of no more than 0.8 mm is permitted ； If the depth of the microcracks is greater than 0.8 mm, the casting should be scrapped. 7.7.3.6 Pressure-bearing components of castings shall be subjected to radiographic inspection on a piece-by-piece basis; the inspection scope shall comply with ASME B16.34 standards, and the inspection method shall follow MSS SP-54 standards. The test results shall meet the following requirements: (1) Pores (A): not less than grade 2. (2) Sand inclusion (B): Not less than grade 2. (3) Shrinkage cavities (CA, CB, CC, CD): Not less than grade 2. (4) Thermal cracks and cold cracks (D, E): None. (5) Inlays (chills, chaplets): None. 7.7.3.7 For carbon steel and alloy steel castings, magnetic particle inspection shall be performed on each piece; the inspection shall be carried out in accordance with ASTM E709 standard. The inspection results shall meet the following requirements: (1) There shall be no hot cracks or cold cracks. (2) The length of any linear display shall not exceed 2 mm. (3) The size of a single circular defect shall not exceed 3 mm. (4) The cumulative length of defects shall not exceed 2 mm in any 100 mm × 100 mm area. 7.7.3.8 For stainless steel castings, liquid penetrant inspection shall be performed on each piece, in accordance with ASTM E165 standard. The inspection results shall meet the following requirements: (1) There shall be no hot cracks or cold cracks. (2) The length of any linear display shall not exceed 2 mm. (3) The size of a single circular defect shall not exceed 3 mm (1 mm for valve stems). (4) The cumulative length of defects shall not exceed 2 mm in any 100 mm × 100 mm area. 7.7.3.9 Defects in pressure-bearing castings may only be removed by grinding; welding repair is not permitted. 7.7.4 For austenitic stainless steel materials, whether in the form of forgings or castings, each batch shall be sampled once for intergranular corrosion testing. The test methods and test results shall meet the requirements of ASTM E262 Method E. 7.7.5 All processed austenitic stainless steel components shall be subjected to acid washing and passivation treatment. 7.7.6 All sealing surfaces (including the valve disc, valve seat, and upper sealing surface) shall be subjected to liquid penetration testing on a piece-by-piece basis; the testing methods and the results of such testing shall meet the requirements of 7.7.3.8. 7.7.7 All valve stem packings shall be capable of withstanding long-term exposure to hydrogen, hydrocarbons, hydrocarbons + hydrogen + hydrogen sulfide at 450°C without failure. That is, ensuring that the leakage level here remains at or below 100 PPm, the service life should be no less than 3 years.