Category Archives: Case Studies

Larry Hanke and Dan Grice will be presenting a talk on A Historical Perspective of Fracture Analysis at the February 19 ASM Symposium at Hennepin Technical College.  The theme of the symposium is “Materials Retrospect: 100 Years of Advancement” in recognition of the 100th anniversary of the MN chapter of ASM International. Other presentations at the event will cover topics such as advancements in the casting industry, metal additive manufacturing and breakthroughs in nitinol in medical device design.

Larry and Dan’s presention will review the history of fractography, including the historical development of the science, changes in the analytical tools, and some historical case histories.
The effective use of materials in various engineering applications requires an understanding of material properties, including conditions of material failure. Fracture is behavior that must be taken into account. The study of fractures over the years has had an important role in materials engineering to improve product performance and reliability.

Dan Grice, P.E. and Larry Hanke, P.E.

Graphitic Corrosion Case Study

posted January 2017

We were asked to determine the mechanism and possible causes of corrosion of a cast iron sanitary sewer pipe. Metallurgical testing and EDS analysis pointed to graphitic corrosion. With graphitic corrosion there is no reduction in the size or shape of the pipe but the strength of the material is severely reduced.

Cross section of vent pipe.

Cross section of vent pipe.

The Vent Pipe case study explains in more detail how this type of corrosion mechanism is identified, causes and our recommendations to the client.

All of the case studies on our website come from our files. They have been edited to present a more casual writing style than our formal reports, but generally they follow the structure of our reports and give an overview of the findings and conclusions from an investigation.

Update to MEE website

posted April 2016

A fire inside a three story stainless steel chamber is the subject of the latest case study added to our webpage.  The goal of the evaluation was to determine what material required replacement or repair, and what material could remain in service. Thus, the evaluation could only be nondestructive. This required an on-site investigation and in situ metallographic examination.

With materials engineering expertise in the behavior of stainless steel under certain conditions ( in this case, elevated temperatures in a carbon-rich environment) and in the analysis of metallographic images, we were able to provide the client with the information he needed to make informed decisions on the future use of this equipment.

Three MEE staff members, Larry Hanke, Dieter Scholz and Roberta Rott attended the Surface Mount Technology Association conference this week in Chicago IL. With three of us there it allowed us to always have someone at our booth in the exhibit hall while others could attend technical talks or participate in SMTA committee meetings.

SMTA is a non-profit international association of companies and individuals involved in all aspects of the electronics industry. The constantly evolving electronics industry presents materials problems that require specialized equipment and creative solutions. MEE has long been a leader in laboratory testing applying traditional and advanced analytical methods to help address product challenges efficiently and effectively.

Visit our website to see examples of typical MEE  projects for electronic components and a case study on failed printed circuit boards.

Booth STMA Chicago 2015_cropped

We would like to tell you that the red and white ribbon on our booth indicates a “best of show – trade show booth” but it is there to identify MEE as a corporate sponsor of SMTA.

Case Studies

posted September 2015

Three new case studies have been added to our website. We think case studies can provide a better understanding of what we do and how we approach typical projects at MEE.  The three newest additions, Leaks in a Fire Protection System. Cracking Capacitors and Fractured Glass Cooking Pot Lid, highlight the range of experience of our technical staff in solving materials-related problems.

IMG_0263

Metallography Laboratory

Carburization – Case Study

posted August 2015

An interesting new case study has been added to our website. We were asked to investigate the failure of perforated steel plates from a gas-fired boiler.  Initial macroscopic examination  was consistent with a corrosion fatigue mechanism.

Stainless steel perforated plate

Further examination using a metallographic light microscope revealed an unusually high concentration of carbides that became more concentrated in a gradient toward the original outer surfaces of the plates. Read the complete case study to learn how carburization of  the plate material during normal service had reduced the strength of the plates.

While determining the failure mode is an important step in any fracture investigation, there is often an underlying cause that may be of greater importance to mitigating or preventing similar failures. MEE’s engineering staff  specialize in the behavior of materials and how their structure affects service performance. Our comprehensive reports combine reliable, analytical data with a sound engineering perspective to provide practical cost-effective solutions to our customers.

 

Stress corrosion cracking in a chemical storage tank, hydrogen damage in a boiler tube, fatigue fracture in titanium sternal plates are just a few of the case studies on our website.   They were specifically chosen to highlight the variety of projects we see in our laboratory and more importantly, demonstrate the thorough, analytical approach we take on all of our projects.

Engineering Consulting_Failure_

Blade failure on wind generator

The goal of a failure analysis is to determine the how and why of a failure.  Laboratory testing at MEE, which may include scanning electron microscopy, Rockwell hardness testing, corrosion testing,  and metallographic evaluation  can help us get answers to the how and why but we also like to work with our client to answer the question of “now what”  in order to minimize future risk of failure.

 

 

Principal Engineer, Larry Hanke, spoke at the spring seminar of the Wisconsin chapter of the International Association of Arson Investigators (IAAI) on materials analysis for fire investigations The purpose of the presentation was to describe and demonstrate what a metallurgical engineer can add to the investigation of a structural fire or explosion. His presentation included an overview of important principles of metallurgical and materials science,  descriptions of the analytical methods used in finding the modes of failure, and case studies of investigations at MEE where material science has been instrumental in the investigation.

The following image was taken at MEE using a metallographic microscope.

Melting from electrical arcing on corrugated stainless steel tubing perforation

Melting from electrical arcing on corrugated stainless steel tubing perforation