Cannon Coating Erosion Model with Updated M829E3 Example
Abstract
Cannons with bore coatings are necessary to reduce erosion in current and future high-performance combat systems. In 1996, we developed a unique erosion model for cannons with bore coatings. Since that time, our results from this model have been published for a number of important Army and Navy gun systems with bore coatings. The erosion model for cannons with bore coatings is guided and calibrated and correlates very well with considerable gun system firing data and subsequent laboratory analysis of fired specimens. Our confidence in the model has grown yearly such that we have decided to publish the details of this model. Coated cannon bore erosion does not simply proceed in an outward to inward progressive ablative fashion, since coatings typically spall instead of progressively ablate. This is the only known erosion model for cannons with bore coatings to account for all aspects of the typical firing-induced cannon erosion mechanism. The typical mechanism includes: Heat-check cracking of the bore coating; Bore coating shrinkage leading to progressive widening of these cracks; Combustion gas-induced interface degradation of the exposed substrate metal; Abrupt interfacial spalling of the bore coating platelets due to linked interfacial degradation that forms pits; Subsequent substrate metal gas wash-to-erosion condemnation A very fine bore coating crack provides a narrow combustion gas path to the metal substrate thus producing limited interfacial substrate degradation. In contrast, a progressively widened/extended bore coating crack due to firing-induced bore coating shrinkage provides a wide combustion gas path to the metal substrate producing substantial interfacial substrate degradation. The purpose of this report is to review typical cannon erosion mechanisms, highlight the resultant cannon coating erosion model, show how this very critical coatings model incorporates
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2000
- Accession Number
- ADA383883
Entities
People
- Samuel Sopok
Organizations
- United States Army Armament Research, Development and Engineering Center