Date: April 2023
Client: KEMI, Finland
Supporting a World-Class Pulp Mill Project
As part of the quality assurance team representing Valmet, our inspector participated in the manufacturing surveillance and quality inspection activities for a series of large evaporator vessels and heat exchangers destined for the Kemi Bioproduct Mill Project in Finland.
The project involved the fabrication of ten large process vessels manufactured from austenitic stainless steel, duplex stainless steel, and super duplex stainless steel. These critical components form part of one of the world’s most advanced pulp production facilities.
-Photo for vessel inspection
Project Highlights
Equipment Scope
- Evaporator Vessels
- Heat Exchangers
- Duplex and Super Duplex Stainless Steel Fabrication
- PED Certified Pressure Equipment
Main Dimensions
- Diameter: 8–11 meters
- Length: 21–28 meters
- Total Quantity: 10 units
The enormous dimensions of the equipment required strict dimensional control throughout fabrication, assembly, welding, and final testing.
Material Verification and Traceability
One of the key inspection activities was ensuring full material traceability from raw material receipt through final assembly.
Materials inspected included:
- 304L Stainless Steel
- S32101 Lean Duplex Stainless Steel
- S31803 Duplex Stainless Steel
- S32550 Super Duplex Stainless Steel
Material certificates were reviewed against project specifications and PED requirements. Positive Material Identification (PMI) verification was also carried out at critical fabrication stages.
Welding Quality Surveillance
Due to the demanding service conditions and corrosion requirements of the process plant, welding quality control was one of the most important aspects of the inspection program.
Inspection activities included:
- Welder qualification verification
- WPS compliance monitoring
- Welding groove inspection
- Interpass temperature control
- Heat input monitoring
- Shielding gas verification
- Visual weld examination
- Carbon contamination prevention
Special attention was given to duplex and super duplex stainless steel welds to ensure phase balance and corrosion resistance were maintained throughout fabrication.
Witnessing Critical Manufacturing and Testing Activities
Following the approved Inspection and Test Plan (ITP), our inspector witnessed and verified numerous fabrication stages, including:
- Plate fabrication and forming
- Nozzle fit-up inspection
- Tube sheet machining inspection
- Tube bundle assembly
- Baffle installation control
- Tube expansion and welding inspection
- Air leak testing
- Hydrostatic testing
- Pickling and passivation inspection
- Cleanliness verification
- Final dimensional inspection
- Packing and preservation inspection
Non-destructive examinations were also reviewed and witnessed, including:
- PT (Liquid Penetrant Testing)
- UT (Ultrasonic Testing)
- Radiographic Film Review
- Ferrite Content Measurement
- PMI Verification
Production Progress Monitoring
In addition to quality surveillance, the inspection team worked closely with the supplier’s production department and subcontractors to monitor fabrication schedules, identify manufacturing risks, and expedite corrective actions when required.
Regular communication between Valmet, Morimatsu, and subcontractors helped ensure that project milestones were achieved while maintaining the required quality standards.
Final Documentation and PED Compliance
Prior to shipment, comprehensive manufacturing records were reviewed to verify compliance with:
- PED 2014/68/EU
- EN 13445
- EN 15614
- ISO 9606
- Client SQS Requirements
The final manufacturing dossier was reviewed and accepted before obtaining the Certificate of Conformity (CoC) from the notified body.
