Determination of Diffusible Hydrogen in Weldments by the RPI Silicone-Oil Extraction Method A reliable, rapid, safe and inexpensive technique for determining diffusible H 2 contents in weldments is developed and qualified

ABSTRACT. The control of the hydrogen content in weldments is necessary to prevent hydrogen-induced cracking in high-yield-strength steels. Because a critical amount of diffusible hydrogen must be present for hydrogen-induced cracking, it is essential to determine the amount of hydrogen introduced by various welding procedures. In this investigation, the RPI silicone-oil-extraction method for the determination of diffusible hydrogen content in weldments was developed and qualified. In this method, diffusible hydrogen in a sample is extracted at 100°C (212°F) in hydrogen-saturated silicone oil and is collected in a buret. This method is a reliable, rapid, safe and inexpensive technique for the determination of diffusible-hydrogen content in weldments. The use of the composite-zone weight, rather than the deposited weld-metal weight, yielded a better consistency of results and a better correlation between these results and those obtained by the BWRA/IIW mercury extraction technique

Weld Heat-Affected-Zone Response to Elevated-Temperature Deformation Constant-displacement-rate testing yields service-performance estimates for HAZ microstructures in 2.25Cr-1Mo steel

ABSTRACT. The mechanical response to elevated-temperature deformation was assessed for weld heat-affected-zone (HAZ) and base-metal microstructures in 2.25Cr-lMo steel. A constant-displacement-rate (CDR) test, capable of determining long-time, notch-sensitivity tendencies, was implemented on a Gleeble 1500 thermal/mechanical simulator and an Instron. Microstructures representative of the coarse-grained, grain-refined, and intercritical regions of the HAZ were simulated on a Gleeble. Microstructural reproduction reflected the preheat and postweld heat treatments in accordance with the required codes. A K~ analysis of the data was conducted, which showed that small-scale yielding criteria were adhered to throughout the test. The highest K, values were fou nd for the base metal. Failure occurred at the peak load for the coarsegrained microstructural region; no K~ analysis was possible. An empirically derived relationship for CrMoV steels between the displacement-at-failure value in the CDR test and the estimated service life was employed. Both the Gleeble and Instron tests showed the coarse-grained region to have the shortest estimated service life. The test results indicated that the hightemperature extensometer control of the Instron was better able to maintain stable crack growth after peak load than the crosshead control of the Gleeble. The CDR test was seen to be an effective, short-time procedure to delineate and compare the strength and relative service life of the structures present in the weld HAZ

NACA Advanced Restricted Reports

Report presenting an investigation of a large variety of different metals used as an intermediate metal between aluminum and steel for the purpose of securing a good bond both from the viewpoint of strength and thermal conductivity. The principal result was that it was found possible to secure a satisfactory bond between aluminum and steel by electroplating the steel with a layer of silver of proper thickness

The Brazing of Aluminum Bronze to Inconel. Progress Report for September 15, 1955 to February 1, 1956

The requirements of an atmosphere for the brazing of Al bronze to Inconel were considered on a thermodynamic basis. It was demonstrated that brazing was not possible in a vacuum or inert gas and is improbable in dry H/sub 2/. Attempts to braze in dry H/sub 2/ prove unsuccessful as predicted, except at isolated spots where filler metal had been preplaced. Modification of the plastic binder for holding the filler metal so as to remove Oi and introduce halogen gave no improvement. Negative results were also obtained when solid halide or halogen was incorporated. Satisfactory brazing was achieved with various solid fiuxes. Consideration was given as to what must be the properties of such a flux so that it should not have deleterious affects in s ervice. (auth