Laser Pulse Heating of Gun Bore Coatings
Abstract
The authors have developed laser pulse heating as a tool for studying erosion processes at gun bore surfaces and for evaluating candidate coatings for bore protection. During firing, the bore coating and steel substrate experience thermal shock from rapid heating and cooling. Thermal pulse durations are in the millisecond range. Despite the short thermal pulse durations, severe coating and substrate degradation processes can occur; these include melting, gas/metal reactions, metallurgical transformations, interface reactions, transformational stresses, and thermal stresses. The degradation processes lead to coating cracking and spallation, which, in turn, allow erosion of the vulnerable underlying steel. Gas/metal interactions may also enhance fracture propagation in the steel. Laser pulse heating is particularly convenient for performing multiple tests on coupon specimens for early evaluations of candidate bore coatings. This allows initial screening of candidate coatings without the difficulty and expense of testing in an actual gun or in a vented combustor. Laser pulse heating has been applied to gun steel that was electroplated with high-contractile chromium, which is the conventional coating for gun bores. Laser pulse heating has also been applied to low-contractile electroplated chromium and bare steel to provide baseline information. In the present laser pulse heating experiments, samples were repeatedly pulse heated to simulate the effects of multiple gun firings. The samples were then sectioned through the pulse-heated areas and examined to assess the resulting degradation. The results validate the approach.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 2001
- Accession Number
- ADA397184
Entities
People
- G. Kendall
- M. E. Todaro
- Paul J. Cote
Organizations
- United States Army Armament Research, Development and Engineering Center