Improvement Of Jet Engine Descaling Procedure

Download this report (PDF, 37.5 MB, 61 pages)
Report Number: WADC TR 52-100
Author(s): Bryan, G. M.
Corporate Author(s): Northrop Aircraft, Inc.
Laboratory: Materials Laboratory
Date of Publication: 1952-08
Pages: 61
Contract: AF 33(038)-23310
DoD Project: None Given
Identifier: AD0004090
AD Number: 4090

Abstract:
X-ray diffraction analysis of the Inconel scale on combustion tube inner liners revealed that it is composed of nickel oxide, the major component, and lesser amounts of chromium oxide and iron oxide. Metallographic examination demonstrated that heavy scale is associated with precipitation, possibly carbides at the grain boundaries, a fact which can explain intergranular corrosion of scaled Inconel in acid solutions. Inconel scale could not be taken off in neutral or alkaline solvents but several acid solutions were found which remove most of the scale without seriously attacking the base metal. Oxidizing pretreatments, particularly with the alkaline permanganate solution in current use by the Air Force, were shown to promote efficient acid pickling. Physical tests of Inconel specimens descaled with the nitric acid-ferric chloride solution revealed that high teiperature pickling (160 deg F) caused a severe loss in tensile strength whereas room temperature pickling caused no appreciable loss in tensile strength. A full scale test of the nitric acid-ferric chloride solution was performed at Norton Air Force Base, San Bernardino, and satisfactory results were achieved.

Provenance: IIT

Other options for obtaining this report:

Via the Defense Technical Information Center (DTIC):
A record for this report, and possibly a pdf download of the report, exists at DTIC

Via National Technical Report Library:
The NTRL Order Number for this report is: AD004090
A record for this report, and possibly a pdf download of the report, exists at NTRL

Indications of Public Availability
No digital image of an index entry indicating public availability is currently available
There has been no verification of an indication of public availability from an inside cover statement