Radiographic Examination Method | MSS SP-55 [PDF]

This article is about MSS SP-54 and set of guidelines related to radiographic examination methods for pressure-containing castings. This document outlines procedures and standards for radiographic inspections. You can also read and download the full standard document of MSS SP-54.

MSS-SP-54-Done-PDFYAR

1. Purpose and Application:

• The document aims to provide standardized procedures for radiographic examinations, ensuring consistent and satisfactory results.
• These procedures are used voluntarily or when specified in contracts, inquiries, or orders. Mutual agreement between the manufacturer and purchaser is essential for interpreting radiographic acceptance standards.

1. Definitions:

• Refers to external sources (ASTM E 94 Appendix X1 and ASTM E 142 Paragraph 2) for definitions related to radiography.

1. Basis for Use:

• Critical sections of pressure-containing castings must undergo radiographic examination.
• The valve or fitting manufacturer selects these critical sections based on their experience.
• Critical sections are defined by their importance in terms of casting solidification, stress concentration, and their ability to contain pressure.

1. Inspection Guide:

• Refers to ASTM E 94 as an inspection guide.
• Radiographs of castings with varying wall thicknesses are interpreted according to specific ASTM standards (E 446, E 186, and E 280) depending on the thickness range.

This document outline the procedures and standards for radiographic inspections of pressure-containing castings, emphasizing the importance of cooperation between manufacturers and purchasers in applying these standards. It also provides references to specific ASTM standards for interpreting radiographs based on the thickness of the castings.

RADIOGRAPHIC PROCEDURE

Following are the procedures and requirements for radiographic testing of materials.

1. Reference Standards:

• ASTM E 94 (“Standard Guide for Radiographic Testing”) and ASTM E 142 (“Standard Method for Controlling Quality of Radiographic Testing”) should be used as guides for the radiographic testing procedure.

1. Selection of Areas:

• The areas to be radiographed must comply with the specifications outlined in Section 3.1, which identifies critical sections of pressure-containing castings.

1. Film Placement:

• The radiographic film should be placed as close as practically possible to the casting being radiographed.

1. Film and Intensifying Screen:

• Any commercially available intensifying screen (except fluorescent type) may be used.
• All radiographic film must have proper identification markings for orientation and to indicate the organization producing the radiograph and the exposure date.
• Penetrameters (devices used for checking the quality of radiographic images) must be used and should meet the requirements of ASTM E 142.
• The radiographic film used should be equal to or finer-grained than Type 2 in ASTM E 94.

1. Radiograph Techniques:

• Radiographs can be made using multiple film techniques, with either single or multiple viewing, to cover a wider range of casting thicknesses with a single exposure.

1. Photographic Density:

• Radiographs must fall within specific photographic density ranges, depending on the viewing technique used. For single film viewing, the density range is 1.5 minimum to 4.0 maximum. For superimposed viewing of double film, each single film should have a density range of 1.00 minimum to 2.5 maximum, and the double film should have a maximum density of 4.0.

1. Surface Condition:

• The surface condition of the material being radiographed should not interfere with the radiographic contrast or be confused with any indications of defects.

1. Thickness:

• Radiographs of single wall thicknesses should be taken wherever practical.
• Radiographic sensitivity requirements are specified based on material thickness: 2-4T for thicknesses up to and including 0.75 inches (19 mm) and 2-2T for thicknesses greater than 0.75 inches (19 mm).

1. Personnel Qualification:

• The manufacturer is responsible for assigning qualified personnel to perform and interpret radiographic examinations in accordance with this standard practice.
• A qualification record of personnel considered suitable for conducting and interpreting examinations should be available upon request. ASNT Recommended Practice No. SNT-TC-1A provides a recommended procedure for qualifying personnel.

These guidelines ensure that radiographic examinations are conducted systematically and in compliance with recognized standards, with an emphasis on personnel qualifications and the quality of radiographic images.