NM01NAVBLKST

The Curtis Industries NAVSHIPS Ultrasonic Calibration Block is a critical reference standard used in Non-Destructive Testing (NDT) for the calibration and performance verification of ultrasonic flaw detection equipment. This specific block is manufactured in accordance with NAVSHIPS Specification 0900-006-3010/Section 6 (also referenced as NAVSEA TECH PUB #T9074-AS-GIB-010/271, Figure 6-7, and MIL-STD-271G Figure 9). It is often referred to as a "Mare Island block."

The primary purpose of this block is to assist ultrasonic technicians in establishing Distance Amplitude Correction (DAC) curves, determining sensitivity levels, and evaluating the ability to detect and size flaws at various depths within a material. This is achieved through a precisely designed series of side-drilled holes at known depths.

The block is offered in two common material types: 1018 Steel or Aluminum. Both materials are chosen for their consistent acoustic properties, which are essential for reliable calibration. All surfaces are meticulously ground to a 32 Ra (Roughness average) finish, ensuring optimal couplant spread and consistent transducer coupling during scanning. The steel version is often nickel-plated for corrosion resistance.

Each Curtis NAVSHIPS block comes with a Certificate of Conformance or Calibration demonstrating its adherence to the specified dimensions and internal flaw characteristics, traceable to national standards. It is typically supplied in a durable wood case for protection, storage, and transport, safeguarding the integrity and accuracy of this vital NDT standard.

Key Features & Benefits:

• Standard Compliance: Manufactured strictly in accordance with NAVSHIPS Specification 0900-006-3010/Section 6 and MIL-STD-271G Figure 9, ensuring full compliance for naval and other demanding applications.

• Precise Dimensions:12.000" x 3.000" x 1.250" (304.8mm x 76.2mm x 31.75mm), providing a consistent reference for calibration.

• Internal Flaws: Contains six 3/64" (1.19mm) diameter side-drilled through-holes located at specific depths:

  • 0.250", 0.500", 0.750", 1.000", 1.250", 1.500", 1.750", 2.000", 2.250", 2.500", and 2.750" in 0.250" (6.35mm) increments.

  • Some versions may also include an additional near-surface hole at 0.125".

• Distance Amplitude Correction (DAC): The varying depths of the side-drilled holes allow technicians to plot a DAC curve, compensating for signal amplitude changes due to beam spread and attenuation as the ultrasonic pulse travels further into the material.

• Sensitivity Calibration: Used to set the instrument's sensitivity levels to reliably detect flaws of a specific size at different depths.

• Flaw Depth Information: Provides known references for determining the approximate depth of indications found during actual inspections.

• Material Options: Available in 1018 Steel (commonly nickel-plated for corrosion resistance) or Aluminum (e.g., 7075-T6 or 6061-T6), allowing for testing in acoustically similar materials to the component being inspected.

• Surface Finish: All surfaces are precisely ground to a 32 Ra (Roughness average) finish, which is crucial for optimal couplant application and stable transducer coupling, minimizing signal loss or noise.

• Engraved Markers:MTDs (Material Thickness Depth) are engraved near both scan edges on one face, facilitating precise measurements.

• Documentation: Includes a Certificate of Conformance/Calibration, traceable to national standards. Optional full-dimensional inspection reports may be available.

• Protective Wood Case: Supplied with a custom-fitted wood case to protect the block from damage, corrosion, and contamination during storage and transport, preserving its accuracy and longevity.

Applications:

• Ultrasonic Flaw Detection: Calibration and functional verification of ultrasonic flaw detectors.

• Aerospace & Defense: Essential for NDT procedures in naval shipbuilding, aerospace manufacturing, and military equipment inspection.

• Industrial NDT: Used in power generation, petrochemical, manufacturing, and other industries where precise ultrasonic inspection is required.

• Training & Education: A fundamental block for NDT training schools and certification programs.

• Procedure Qualification: Developing and qualifying ultrasonic inspection procedures.