For the confirmed P275N steel plate order, our company arranged and accompanied the customer to conduct a detailed on-site inspection at the steel mill, focusing on production status, process control, and quality testing.
The inspection was carried out in accordance with EN 10028-3 and the technical conditions agreed in the order.
Order and Material Identification
The inspected material was P275N normalized pressure vessel steel plate. Before entering production areas, the customer verified the following information:
Steel grade: P275N
Standard: EN 10028-3
Delivery condition: Normalized (N)
Heat number and plate number
Plate marking and traceability records
All plate identification markings were consistent with the mill production records, ensuring full traceability from steelmaking to finished products.
Steelmaking and Slab Quality Control
The inspection began at the steelmaking section. The customer reviewed:
Converter steelmaking process
Ladle refining and chemical adjustment
Sampling method for heat analysis
Slab surface condition and internal quality control
Slabs used for the P275N order were produced from qualified heats and visually inspected before rolling. Slab reheating temperatures were recorded and monitored.
Hot Rolling Process Control
During hot rolling, the following parameters were checked on site:
Rolling schedule and reduction ratio
Plate thickness control during finish rolling
Temperature control at rolling exit
Plate width and length tolerance
Operators confirmed that rolling parameters were adjusted according to plate thickness to ensure uniform mechanical properties across the plate.
Normalizing Heat Treatment
All P275N plates for this order underwent normalizing heat treatment. The customer inspected the normalizing furnace and reviewed furnace records, including:
Heating temperature range
Holding time
Cooling method
The normalizing process ensured refined grain structure and stable performance required for pressure vessel applications.
Chemical Composition Verification
Chemical composition testing was performed in the mill laboratory using samples taken from the same heat.
Table 1: Chemical Composition – P275N Steel Plate (wt.%)
| Element | C | Si | Mn | P | S | Al |
|---|---|---|---|---|---|---|
| EN 10028-3 Requirement | ≤0.20 | ≤0.40 | 0.80–1.50 | ≤0.025 | ≤0.015 | ≥0.020 |
| Test Result | 0.14 | 0.29 | 1.34 | 0.019 | 0.006 | 0.038 |
All elements complied with the standard requirements and were recorded in the heat analysis report.
Mechanical Property Testing
Mechanical tests were conducted on normalized test specimens prepared from finished plates.
Table 2: Mechanical Properties of P275N Steel Plate
| Test Item | Standard Requirement | Test Result |
|---|---|---|
| Yield Strength (MPa) | ≥275 | 322 |
| Tensile Strength (MPa) | 410–560 | 468 |
| Elongation (%) | ≥22 | 29 |
| Impact Test | As specified in order | Passed |
The test results confirmed stable strength and sufficient ductility for pressure vessel fabrication.
Ultrasonic Testing and Final Inspection
Each finished plate was subjected to ultrasonic testing (UT) in accordance with the specified inspection level. The customer observed the UT operation and reviewed inspection records.
Final inspection also included:
Plate thickness measurement
Flatness and edge condition check
Surface quality inspection
Plate marking verification
No unacceptable internal defects were detected, and all inspected plates met acceptance criteria.
Customer Review and Acceptance
After completing the inspection, the customer reviewed all relevant documents, including production records, laboratory test reports, and UT results.
Based on the on-site verification, the customer confirmed that the P275N steel plates meet EN 10028-3 requirements and order specifications, and approved the continuation of production and delivery.
We will continue to follow established quality control procedures to ensure reliable supply and consistent quality of P275N pressure vessel steel plates for our customers.
