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Title: DEVELOPMENT OF ELECTROPLATING PROCESSES TO ELIMINATE HYDROGEN EMBRITTLEMENT IN HIGH-STRENGTH STEEL. Period Covered: February 1956 to May 1957

Abstract

The embrittlement of cadmium plated high-strength steels e.g., (SAE 4340) by hydrogen is of serious concern to the Air Force. Unexpected failures of highly stressed components have been experienced. It has been found that cadmium plating from a sulfamate, a perchlorate, or a fluoborate bath wdth addition agents can be accomplished without embrittling the steel, but that the quality and adherence of the cadmium plate emerging from these baths as compared with the cadmium plate from a cyanide bath, indicates the need for further evaluation before use. In order to evaluate the effects of various degrees of hydrogen embrittlement on the steel, a sensitive mechanical test method was required. The important criteria were that the test coupon be of such geometry that it could be plated uniformly and that the test would evaluate only the effect of hydrogen embrittlement. Simple bend tests and notched bar tensile tests have been commonly used for studying the embrittling effect. The bend test, torsion test, and static sustained load beam test were investigated. A static sustained load beam test, using a 9- x 1/4- x 1/2-in. specimen with the grain transverse to the length was adopted. The SAE 4340 specimens were heat treated tomore » 280,000 to 300,000 psi tensile strength and the fracture time, under a given stress, was taken as a measure of the degree of hydrogen embrittiement. it was found that replicate specimens show a large deviation in fracture times in spite of the care that was given to the selection preparatlon, and testing techniques. These deviations are due to the normal defects and variables that are present in commercial, air melted, aircraft quality steel. (auth)« less

Authors:
Publication Date:
Research Org.:
Stanford Research Inst., Menlo Park, Calif.
OSTI Identifier:
4306771
Report Number(s):
WADC-TR-57-514; AD-142316
NSA Number:
NSA-12-007268
DOE Contract Number:
AF33(616)-3429
Resource Type:
Technical Report
Resource Relation:
Other Information: Project title: FINISHES AND MATERIALS PRESERVATION. Task title: ELECTRODEPOSITION AND ELECTROCHEMICAL TREATMENTS. Orig. Receipt Date: 31-DEC-58
Country of Publication:
United States
Language:
English
Subject:
MINERALOGY, METALLURGY, AND CERAMICS; ADHESION; AIR; AIRCRAFT; BORIDES; BRITTLENESS; CADMIUM; CHLORIDES; CONTROL; CYANIDES; DEFECTS; ELECTROCHEMISTRY; ELECTRODEPOSITION; ELECTROPLATING; FAILURES; FLUORIDES; GRAIN BOUNDARIES; HEAT TREATMENTS; HYDROGEN; MATERIALS TESTING; MECHANICS; MELTING; PLATING; PREPARATION; ROTATION; STEELS; STRESSES; SULFATES; TENSILE PROPERTIES; VARIATIONS

Citation Formats

Chilton, J.E.. DEVELOPMENT OF ELECTROPLATING PROCESSES TO ELIMINATE HYDROGEN EMBRITTLEMENT IN HIGH-STRENGTH STEEL. Period Covered: February 1956 to May 1957. United States: N. p., 1957. Web.
Chilton, J.E.. DEVELOPMENT OF ELECTROPLATING PROCESSES TO ELIMINATE HYDROGEN EMBRITTLEMENT IN HIGH-STRENGTH STEEL. Period Covered: February 1956 to May 1957. United States.
Chilton, J.E.. Fri . "DEVELOPMENT OF ELECTROPLATING PROCESSES TO ELIMINATE HYDROGEN EMBRITTLEMENT IN HIGH-STRENGTH STEEL. Period Covered: February 1956 to May 1957". United States. doi:.
@article{osti_4306771,
title = {DEVELOPMENT OF ELECTROPLATING PROCESSES TO ELIMINATE HYDROGEN EMBRITTLEMENT IN HIGH-STRENGTH STEEL. Period Covered: February 1956 to May 1957},
author = {Chilton, J.E.},
abstractNote = {The embrittlement of cadmium plated high-strength steels e.g., (SAE 4340) by hydrogen is of serious concern to the Air Force. Unexpected failures of highly stressed components have been experienced. It has been found that cadmium plating from a sulfamate, a perchlorate, or a fluoborate bath wdth addition agents can be accomplished without embrittling the steel, but that the quality and adherence of the cadmium plate emerging from these baths as compared with the cadmium plate from a cyanide bath, indicates the need for further evaluation before use. In order to evaluate the effects of various degrees of hydrogen embrittlement on the steel, a sensitive mechanical test method was required. The important criteria were that the test coupon be of such geometry that it could be plated uniformly and that the test would evaluate only the effect of hydrogen embrittlement. Simple bend tests and notched bar tensile tests have been commonly used for studying the embrittling effect. The bend test, torsion test, and static sustained load beam test were investigated. A static sustained load beam test, using a 9- x 1/4- x 1/2-in. specimen with the grain transverse to the length was adopted. The SAE 4340 specimens were heat treated to 280,000 to 300,000 psi tensile strength and the fracture time, under a given stress, was taken as a measure of the degree of hydrogen embrittiement. it was found that replicate specimens show a large deviation in fracture times in spite of the care that was given to the selection preparatlon, and testing techniques. These deviations are due to the normal defects and variables that are present in commercial, air melted, aircraft quality steel. (auth)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Nov 01 00:00:00 EST 1957},
month = {Fri Nov 01 00:00:00 EST 1957}
}

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  • The embrittiement of high strength steels due to the action of H introduced by Cd-electroplating was studied in sustained-load, rotating beam fatigue, and bending tests. Strength levels from 180,000 to 300,000 psi as suitable for the various steels were examined for a variety of initial conditions of stress concentration. All steels were found to be embrittled in some measure after Cd-plating and this embrittlement could not be fully eliminated, as determined in the bend test, through the baking treatment used. The improvement in properties which did result from baking was promoted by a redistribution and not an elimination of Hmore » from the steel. Failure promoted by Cd-plating is affected by the experimental conditions and has been discussed at length in the report. In the H bearing zone a crack is initiated and then depending on the experimental conditions may propagate to failure of the cross section through overloading. Crack development is apparently dependent, in part, on the composition and is minimized by reduction in C content or by an increase in Si content. Bath the sustained-load and bend tests are suitable tests for evaluation of H embrittlement in ultra-high strength steels. The rotating beam fatigue test is a relatively insensitive test of H embrittlement, but can be used to provide an excellent measure of the ''static'' notch strength of the steel. (auth)« less
  • A reliable and sensitive test procedure for ascertaining detrimental hydrogen embrittlement as a result of cadmium plating was established. The test consists of a sustained loaded notched tensile specimen, loaded at 75% of the ultimate notched tensile strength for a minimum of 200 hours. Detrimental hydrogen embrittlement is shown to be dependent upon the steel alloy, the current efficiency of the cadmium plating bath, and the physical structure of cadmium coating obtained. Current efficiency- current density curves were obtained for the convertional cadmium cyanide bath, the high efficiency cadnnium cyanide bath, the cadmium suifamate bath, and the cadmium fluoborate bath.more » Cadmium electroplating processes for coating highstrength steel, 280,000 psi UTS, without detrimental hydrogen embrittlement are given. Vacuum cadmium metallizod coatings are also shown to be non-embrittling to high-strength steels. (auth)« less
  • Studies were conducted to determine the importance of beta grain size as a contributing factor to the loss of ductility that occurs when titanium alloys are heat treated at temperatures above thc beta transus. in a second phase of the research a heat-treatment program was carried out in an effort to develop procedures for restoring ductility in beta-embrittled material. To supplement these studies, a microscopic study of deformation in pcrtincnt microstructores was conducted. The primary cause of beta embrittlemcnt is the large grain size which is obtained so rapidly in many alpha-beta titanium alloys when heated into thc beta field.more » Grainboundary alpha and acicular intragranular alpha in the microstructure are not detrimental if the beta grain size is fine. The structures resulting from beta treatments anre quite stable and can not bc significantiy altered in a beneficial way by heat treatment alone. Certain alloys (such as Ti-16V-2.5Al) show a relatively low rate of beta grain growth. Development of alloys exhibiting this property appears to offer the most promising means of avoiding or minimizing beta-embrittiemeat effects. (auth)« less