1.1This practice describes a general procedure for using the process compensated resonance testing (PCRT) via swept sine input method to perform part-to-itself (PTI) examination on populations of newly manufactured and in-service parts. PCRT detects resonance pattern differences in metallic and non-metallic parts. Standard Practice E2534 for Defect Detection with PCRT and Standard Practice E3081 for Outlier Screening with PCRT cover the development and application of PCRT sorting modules that inspect a part at a single point in time. These methods use the resonance frequency spectra recorded from test parts, and perform different statistical analyses to compare test parts to reference populations. These comparisons include, and must compensate for, the normal geometric, material, and processing variations present in any population of parts. In many applications, however, the user may need to isolate the and evaluate the effects of a single processing step or in-service load. For example, a manufacturer may want to perform process monitoring and control on a heat treatment or hardening process. A maintainer may want to evaluate the effect of service cycles in an engine. A PCRT PTI test measures the resonance frequency spectrum of a part at two points in time, such as before and after a manufacturing process step, and calculates the change in resonance frequencies to evaluate the effect of the intervening process. Control limits can be set on the frequency change to field a PTI PASS/FAIL inspection capability. The limits may be based on training populations of parts with acceptable and unacceptable levels of change, model predictions of the effects of part changes, or criteria derived from process control practices. Manufacturing processes and in-service loads that can be evaluated with a PCRT PTI inspection include, but are not limited to heat treatment, hot isostatic pressing (HIP), shot peening, induction hardening, carburization, coating, thermal history changes, residual stress changes, creep, plastic deformation, corrosion and fatigue. This practice is intended for use with instruments capable of exciting, measuring, recording, and analyzing multiple, whole body, mechanical vibration resonance frequencies in acoustic and/or ultrasonic frequency ranges.
Users are asking for an ASTM standard practice that can be included on component drawings and/or maintenance manuals to require PCRT part-to-itself (PTI) examinations or allow them as an alternate inspection. Other users are developing their own internal specifications, but wish to base them on an ASTM standard. The primary users will be industry manufacturers that will use PTI to evaluate the effects of manufacturing process steps (such as hardening, hot isostatic pressing (HIP), and heat treatment) and industry/government maintainers that will use PTI to evaluate the effects of operational service intervals.
Keywordsdamage identification; elastic properties; feature extraction; in-service monitoring; life monitoring; nondestructive examination; nondestructive inspection; part-to-itself; PTI; process compensated resonant examination; process compensated resonant testing; PCRT; process control; process monitoring; production variation; quality control; resonance inspection; resonances; resonant frequency; resonant mode; resonant ultrasound spectroscopy; statistical process control; system health monitoring; vibration characteristics
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Draft Under Development