Stress Corrosion Cracking Of 17 4 Ph Stainless Steel

The susceptibility of 17-4PH to hydrogen-stress cracking was found to increase as the hardness of the steel increased from 42 to 47 R sub c. Conditions of hydrogen-stress cracking were created by attaching a piece of aluminum (7075-T6) to a stress corrosion test specimen. In the absence of aluminum, under identical test conditions, no stress-corrosion cracking failures were recorded in times up to 1000 hr. Charging the bolts with hydrogen and statically loading the bolts in air produced failure times similar to those obtained with the test samples coupled to the aluminum alloy and periodically immersed in a 3-1/2% salt solution. When the 17-4PH was over-aged to a hardness of 40 R sub c or less, the susceptibility was eliminated. These variations in hardness did not change the yield point of the bolt (as determined by the Johnson's 2/3 method). Three additional methods of protection against hydrogen-stress cracking were evaluated: nickel-cadmium electroplating of the bolts, anodizing the aluminum, and insulating with a lubricant at the aluminum/stainless steel interface. Nickel-cadmium plating (AMS-2416) the 17-4PH to a thickness of from 0.2- to 0.4- mil nickel/0.1- to 0.2- mil cadmium offered no resistance to hydrogen-stress cracking. The remaining two methods proved effective in inhibiting hydrogen-stress cracking under controlled laboratory conditions, but, with poor handling procedures, the dissimilar metal couple could be easily activated and cause failure by hydrogen-stress cracking. (Author).

The problem of stress corrosion cracking (SCC), which causes sudden failure of metals and other materials subjected to stress in corrosive environment(s), has a significant impact on a number of sectors including the oil and gas industries and nuclear power production. Stress corrosion cracking reviews the fundamentals of the phenomenon as well as examining stress corrosion behaviour in specific materials and particular industries. The book is divided into four parts. Part one covers the mechanisms of SCC and hydrogen embrittlement, while the focus of part two is on methods of testing for SCC in metals. Chapters in part three each review the phenomenon with reference to a specific material, with a variety of metals, alloys and composites discussed, including steels, titanium alloys and polymer composites. In part four, the effect of SCC in various industries is examined, with chapters covering subjects such as aerospace engineering, nuclear reactors, utilities and pipelines. With its distinguished editors and international team of contributors, Stress corrosion cracking is an essential reference for engineers and designers working with metals, alloys and polymers, and will be an invaluable tool for any industries in which metallic components are exposed to tension, corrosive environments at ambient and high temperatures. Examines the mechanisms of stress corrosion cracking (SCC) presenting recognising testing methods and materials resistant to SCC Assesses the effect of SCC on particular metals featuring steel, stainless steel, nickel-based alloys, magnesium alloys, copper-based alloys and welds in steels Reviews the monitoring and management of SCC and the affect of SCC in different industries such as petrochemical and aerospace

Recent unexpected occurrences of stress-corrosion cracking (SCC) with 17-4 PH structural components indicated a need for improved characterization of the alloy and application of more advanced analytical procedures for reliably predicting structural performance. Accordingly, the purpose of the present studies was to establish systematically the SCC properties of 17-4 PH steel over a wide range of yield strengths and applied cathodic potentials. Six different heat treatments were selected for the SCC studies. The data, when analyzed in terms of ratio analysis procedures, are immediately useful for predictions of service reliability of the steel in marine structures.