Failure Mechanisms
Public Failure Mechanisms
Active 2 weeks ago
Welcome to [NDT Inspection Portal]’s failure mechanism group, a place for professionals to connect... View more
Public Failure Mechanisms
Group Description
Welcome to [NDT Inspection Portal]’s failure mechanism group, a place for professionals to connect and discuss the latest techniques and technologies in the study of failure mechanisms. The study of failure mechanisms is an important aspect of ensuring the safety, reliability, and performance of products, materials, and structures in various industries. It involves the analysis of how and why a component or system fails under various conditions and the identification of the underlying causes of failure.
Failure mechanisms can be complex and can involve a range of factors, including material properties, design, manufacturing processes, environmental conditions, and operating conditions. The study of failure mechanisms involves the use of various methods and techniques, including mechanical testing, metallurgical analysis, and computer modeling, to evaluate the performance and behavior of a component or system under different loads and conditions.
Our member group offers a platform for sharing knowledge and best practices on the study of failure mechanisms and its applications in various industries. Join our community of experts from around the world and be a part of the conversation on advancing the understanding of failure mechanisms and improving the performance and reliability of products, materials, and structures. Whether you are new to the study of failure mechanisms or an experienced professional, you’ll find valuable resources and a welcoming community in our group.
Hydrogen damage
Hydrogen damage
Posted by arsal on 27/11/2021 at 2:06 pmI would like to know what Technics we can use to detect hydrogen damage and creep voices in steel pressure vessels
Thankslucas replied 3 years ago 2 Members · 1 Reply- 1 Reply
There are a few methods used to inspect hydrogen damage. It is
important to know which type of hydrogen damage you are looking for (ie.
Wet Hydrogen Damage or High Temperature Hydrogen Damage).
WET HYDROGEN DAMAGE: This is a fairly easy failure mechanism to detect
and quantify if the proper testing equipment is utilized. I have used
Automated Ultrasonic systems which tend to remove a lot of the human
error, intern producing the best test results. There are several
multi-channel automated ultrasonic systems on the market today which
allow you to overlay the various shear wave angle (ie 45 degree) and
compression wave (ie 0 degree) transducer data. With both 0 degree and
45 degree data overlaid it is very easy to identify damaged areas and
also identify linkage between the swelling planer inclusions.
HIGH TEMPERATURE HYDROGEN DAMAGE: This one is a little more challenging
to detect and quantify in the early stages of damage. One method taught
by Chevron U.S.A. is a Velocity Ratio Comparison (VRC) and Shell Oil Co.
also has their own method. The VRC method initially uses a 0 degree
compression wave to locate noise ratio increase near the back 1/3 of the
backwall. When noise of a predetermined ratio is exceeded, a
oscilloscope is used in conjunction with a “0 degree shear” and “0
degree compression” wave transducers to determine the velocity of each
in the material at that point. The two velocities are then compared to
determine if they exceed the determined attenuation differences.
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