Quality Control Built Into Every Stage Of Production
For valve distributors, project contractors and importers, product consistency is often more important than the lowest price.
A valve that fails after installation can result in replacement costs, project delays and damage to customer relationships. For this reason, quality control at Keylion focuses on preventing defects during production rather than relying solely on final inspection.
Our inspection procedures cover incoming materials, production processes and finished products before shipment.
Incoming Material Inspection
Production begins with verification of incoming materials before they enter the manufacturing process.
Ductile Iron Components
Each batch of cast components is visually inspected to identify defects that could affect product performance, including:
Surface shrinkage
Casting cracks
Sand inclusions
Visible deformation
Components that do not meet production requirements are rejected before machining.
Rubber Components
Valve sealing performance depends heavily on rubber quality.
Incoming EPDM and NBR components are checked for:
Surface defects
Hardness consistency
Dimensional accuracy
Storage condition compliance
Fasteners And Hardware
Bolts, nuts and washers are inspected to verify:
Material specification
Thread quality
Surface condition
Corrosion protection
Casting Inspection
Before machining begins, castings undergo additional inspection.
Key inspection points include:
Surface Quality
Inspection for:
Blow holes
Cracks
Surface irregularities
Casting defects
Structural Integrity
Critical casting areas such as flange connections and pressure-bearing sections are checked to ensure proper formation.
Dimensional Verification
Major casting dimensions are verified against production drawings before further processing.
Machining Inspection
Valve performance depends on machining accuracy.
During production, key dimensions are inspected to ensure proper assembly and sealing.
Flange Dimensions
Verification includes:
Bolt hole position
Bolt hole diameter
Flange thickness
Flange face accuracy
Internal Dimensions
Inspection of:
Bore diameter
Guide surfaces
Sealing areas
Thread Inspection
For threaded components:
Thread profile
Thread depth
Assembly compatibility
Coating Inspection
Protective coating plays a critical role in extending valve service life.
After surface treatment and coating, products undergo coating inspection.
Surface Preparation Check
Verification that surfaces are properly cleaned before coating application.
Coating Thickness Measurement
Random samples are measured to confirm coating thickness consistency.
Coating Coverage
Inspection ensures complete coverage of:
Valve body
Flanges
Hard-to-reach areas
Adhesion Inspection
Coating adhesion is checked to reduce the risk of premature coating failure during transportation and installation.
Pressure Testing
Pressure testing is performed before shipment to verify sealing and pressure retention performance.
Shell Pressure Test
This test verifies the structural integrity of the valve body and pressure-containing components.
The valve is subjected to specified test pressure to confirm there is no visible leakage from the body.
Seat Leakage Test
This test verifies sealing performance when the valve is in the closed position.
The objective is to ensure the seat and sealing components function as intended.
Operational Check
Valve opening and closing operation is verified to ensure smooth movement and proper functionality.
Final Product Inspection
Before packing, finished products undergo final inspection.
Appearance Verification
Inspection includes:
Surface condition
Coating appearance
Product cleanliness
Product Identification
Verification of:
Valve size markings
Pressure ratings
Customer logo requirements
Nameplate information
Packaging Inspection
Inspection of:
Packaging materials
Product protection
Label accuracy
Shipping marks
Production Record Management
Inspection records are maintained throughout the production process.
These records support:
Batch identification
Production tracking
Internal quality review
After-sales investigation when required
For repeat orders, production records help maintain consistency across multiple shipments.