IMPORTANCE OF FLAT BOTTOM HOLES (FBH) and SIDE DRILLED HOLE (SDH)
Service Overview
Flat Bottom Holes (FBH) and Side Drilled Holes (SDH) are
widely used ultrasonic reference reflectors because their geometry and location
can be controlled accurately. They provide repeatable responses for
calibration, sensitivity setting, distance-amplitude correction and equipment
or probe comparison when selected in accordance with the relevant inspection
procedure.
Scope of Service
1. Select
FBH or SDH according to the applicable code, procedure and inspection
objective.
2. Define
reflector diameter, depth, sound path and orientation.
3. Match
reference-block material and acoustic properties to the inspection application.
4. Machine
controlled reflector locations with suitable tolerances.
5. Verify
dimensions and ultrasonic response where included.
Available Specimen and Component Configurations
1. Flat
calibration blocks.
2. Step
blocks and distance-amplitude blocks.
3. Curved
pipe or vessel reference blocks.
4. Weld and
plate mock-ups incorporating FBH or SDH targets.
5. Custom
blocks for encoded PAUT or automated inspection systems.
Flaws, Reflectors or Conditions Covered
1. Flat
Bottom Holes (FBH) with controlled diameter and remaining ligament.
2. Side
Drilled Holes (SDH) with controlled diameter and position.
3. Combined
FBH/SDH blocks where technically appropriate.
4.
Additional notches or surface reflectors where required by the
procedure.
Supported NDT Methods
The product, specimen or service can support the following
NDT methods where technically applicable. Final suitability is confirmed
against the material, geometry, target condition and intended equipment
configuration.
1.
Conventional Ultrasonic Testing.
2. Phased
Array Ultrasonic Testing (PAUT).
3.
Automated Ultrasonic Testing (AUT).
4. FMC/TFM
and encoded ultrasonic techniques.
5.
Immersion ultrasonic testing where applicable.
Typical Applications
1.
Time-base and sensitivity calibration.
2.
Distance-amplitude correction or reference-level establishment.
3. Beam
characterisation and probe comparison.
4.
Procedure development and equipment verification.
5. Training
and personnel qualification exercises.
Industries Served
1. Oil and
gas and pipeline inspection.
2. Power
generation and pressure equipment.
3.
Aerospace and high-integrity manufacturing.
4.
Forgings, castings and steel products.
5. NDT
training centres and equipment manufacturers.
Applicable Codes, Standards and References
The work may be designed, manufactured or performed with
reference to the following, as applicable to the agreed scope:
1. ASME and
ASTM ultrasonic requirements where applicable.
2. AWS,
API, ISO, EN and BS references as specified.
3.
Customer/OEM procedures and approved drawings.
4. Employer
written practices for training and qualification.
The customer should identify the exact document, edition and
revision. Reference to a standard does not by itself constitute certification,
accreditation or approval by the issuing body.
Project Workflow
1. Requirement Review: Review the
application, method, component, material, geometry, equipment and intended use.
2. Technical Definition: Confirm drawings,
dimensions, flaw or reflector schedule, tolerances, access and documentation
requirements.
3. Design Approval: Issue the proposed
technical basis or layout for customer review where custom manufacture is
required.
4. Manufacturing or Service Execution:
Complete fabrication, machining, flaw introduction, marking, inspection or
preparation under controlled instructions.
5. Verification: Check agreed dimensions,
identification, reflector locations and relevant NDT responses using suitable
methods.
6. Documentation and Delivery: Compile
agreed records, protect the items and arrange domestic or international
dispatch.
Documentation and Deliverables
Depending on the agreed scope, the deliverable package may
include:
1. Approved
drawing or technical layout, where applicable.
2. Material
and component information, where included.
3. Flaw,
reflector or reference-feature schedule and location map.
4.
Dimensional inspection record.
5. NDT
verification record, where included.
6. Unique
identification, engraving or labelling details.
7.
Photographic record where requested.
8.
Certificate of conformity for the agreed manufacturing or service scope.
9. Packing,
preservation and handling information.
Why Choose NDE Flaw Tech India?
1.
Application-specific engineering rather than one-size-fits-all
selection.
2. Support
for conventional and advanced NDT methods where technically applicable.
3.
Controlled machining, flaw introduction, identification and custom
fabrication capabilities.
4. Open,
blind and partially blind documentation options for training and assessment
programmes.
5.
Traceable drawings, flaw maps, dimensional records and verification
information when included in the scope.
6. Support
for domestic and international customers, subject to logistics and applicable
restrictions.
Information Required for a Technical and Commercial Proposal
1. Required
ultrasonic method and procedure.
2. Block
material and heat-treatment condition if relevant.
3. Block
geometry and dimensions.
4. FBH or
SDH diameter, depth and location.
5. Probe,
wedge, frequency and sound-path information.
6.
Applicable code, standard and revision.
7.
Documentation and verification requirements.
Technical Limitations and Responsibilities
1. FBH and
SDH responses are not interchangeable; each has different acoustic behaviour.
2.
Reference-block material and geometry can significantly influence
amplitude and sound path.
3. Deep or
small-diameter reflectors may be limited by drilling access and verification
capability.
4.
Reflector tolerances must be agreed before manufacture.
5. Final
calibration use must follow the governing inspection procedure.
Frequently Asked Questions
What is the main difference between FBH and SDH?
An FBH presents a flat reflecting face, while an SDH
presents a cylindrical surface. Their ultrasonic responses differ and the
correct type should follow the inspection procedure.
Can both FBH and SDH be made in one block?
Yes, where the layout provides adequate spacing and the
combined design is technically useful.
Can you manufacture curved blocks?
Yes. Pipe- or component-curvature blocks can be considered
based on material, diameter, thickness and machining access.
Can FBH depth be controlled precisely?
FBH depth and remaining ligament can be controlled within
agreed machining and inspection tolerances.
Are FBH or SDH blocks automatically code compliant?
No. Compliance depends on the exact material, geometry,
reflector dimensions and the specified edition of the applicable code or
procedure.
Request a Proposal
Provide the ultrasonic method, applicable standard,
material, geometry and required FBH/SDH dimensions. We will review the
reflector layout and propose a suitable reference block or specimen.