Energy Dispersive X-ray Spectroscopy (EDX)

EDX is an analytical technique used for the elemental analysis of a material. In EDX a beam of electrons bombards the top surface of the sample. If the incoming electron beam is of sufficient energy it will cause inner shell electrons of the affected atoms to become excited and thus ejected from its bond to the nucleus of the atom. When this happens, an electron from an outer, higher energy, shell drops down to take its place. That electron must release some of its energy in order to fit into the inner, lower energy shell. That release of energy, in X-ray form, is then collected, counted, and converted into weight or atomic percentages. EPI Materials Testing Group uses our EDX in the elemental analysis of many different materials in the daily process of running failure analyses and the wide array of testing services that we perform from corrosion products to identifying particles in filtrate.

HARDNESS TESTING

Hardness is the measurement of how resistant a material is to a permanent change in shape.  The hardness of a material is dependent on many different physical properties like ductility, strength, and toughness.  EPI-MTG has experience performing hardness testing on a wide range of alloys, as well as plastic, rubber, and ceramic/carbide.  EPI-MTG has the ability to perform hardness testing using the Knoop (HK), Vickers (HV), Rockwell (HRA, HRB, HRC, HRD, and HRE), and Brinell (BHN) hardness scales.  

Knoop Hardness Testing on OD of Pipe

Arc/Spark Optical Emission Spectroscopy

Arc/Spark Optical Emission Spectroscopy is an analytical technique used to obtain the elemental composition of different alloys with varying base materials.  An electrical arc is passed through a sample, under an argon atmosphere, heating and exiting the atoms within the material.  While discharging energy the atoms give off a characteristic wavelength of light that is detected and measured to obtain an accurate weight percentage of the elements present in the sample.

 

EPI-MTG has a Thermo Scientific ARL 3460 Metals Analyzer.  We are capable of analyzing metals that have a base material of Iron, Nickel, and Copper.

X-ray Diffraction
 

X-ray Powder Diffraction gives us the capability to not only identify a sample elementally, but to identify the chemical compounds present in your sample as well.  As you can see in the image above we identified two different Calcium Carbonate phases, and Silicon Dioxide as well.  We have utilized this technique to help our clients identify samples from a myriad of environments and locations.  From corrosion product and solids removed from filtration systems, to drilling mud and geological samples we have it covered.

This is a 50x photo of the cross section of a CN7M valve body, chemically etched with a mixture of HCl and FeCl3.  The photo shows intergranular cracking and large grains measuring approximately .25" wide.

METALLOGRAPHIC CHEMICAL ETCHING

Chemically Etched Cross Section of Butt Weld.

Metallographic Chemical Etching is the process of using a reagent (a mixture of acids, bases, and/or other chemicals) to highlight or distinguish certain features of a material.  Etching can be performed on a large part having physical characteristics that can be seen with the naked eye, or on a smaller microscopic level that has to be examined with our optical or scanning electron microscope.   Chemical etchants can expose things like grain boundaries, compositional differences, and metallic phase differences along with things like carbides and inclusions.  Metallographic Chemical Etching is both an important technique and a helpful tool here at EPIMTG.

Chemically Etched Cast Iron Microstructure

Meet the Staff - Randall Moye

This week we will be introducing EPI Materials Testing Group's Lab supervisor, Randall Moye. Randall has worked for EPI Materials Testing Group for over 6 years, but has about 15 years experience in the testing and analysis industry.

Randall is a military veteren and knows how to keep the lab running on all cylinders. Along with making sure work is getting done right in our lab, he also runs many of EPI MTG's analyses including our X-ray diffraction analysis. This test identifies compounds of crystalline material.

At EPI MTG, Randall oversees our entire lab and is one of the main reasons why EPI MTG has been expanding its clientele and production since he was hired on. He is another valued person that makes EPI MTG one of the best testing and analysis labs in the world.

Micro-photography

The picture above shows the grain structure of Direct Sintered Silicon Carbide at 500x. One of many intresting grain structures EPI Materials Testing group sees everyday.

Want to see something we do? Have a question about something? Let us know in the comments and we will give you an answer or even write about it!

B611 Wear Testing

EPI Materials Testing group does custom wear testing and three standardized wear tests for their clients, ASTM G65, G105, and B611.

The B611 test is an ASTM 'Standard Test Method for Abrasive Wear Resistance of Cemented Carbides'. The test wheel is made of AISI 1020 steel and has an OD of between 6.5" and 6.65".

The B611 test is used mainly for what it is intended, Cemented Carbides. It is also used as a research method to test the differences between different carbide compositions. This test runs in a slurry mixture making it very abrasive as compared to the G65 testing.

Along with these test we have talked about for the last few weeks EPI Materials Testing also does custom testing for clients who are doing research and development of new and older carbides.

If you have any questions regarding wear testing visit our website or leave us a comment.

Meet the Staff - Darrell Childers

This week we will be introducing the old man who has done it all for EPI MTG, Darrell Childers. Darrell has worked for EPI Materials Testing Group for about 8 years, but has almost 20 years experience in the forensic analysis background.

During those years, he has been the man who will do anything that was needed of him. He has gathered forensic evidence on location, processed evidence for analysis in both legal cases and QA/QC matters, machined custom tools and parts for jobs, traveled to incident sites around the country, regularly prepared high quality samples for analysis, and a multitude of other things.

At EPI MTG, Darrell is the senior lab technician specializing in high quality samples for analysis and oversees our other lab technicians.

Darrell has been a tremendous asset to EPI MTG and has always been there to help a client or fellow employee with just about any question. He loves the work he does and EPI MTG's clients can see that in every job he works on.

G65 Wear Testing

EPI Materials Testing group does custom wear testing and three standardized wear tests for their clients, ASTM G65, G105, and B611.

The G65 test is an ASTM 'Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus'. The test runs using an eight-inch wheel with a half inch of rubber on the OD of the wheel.

The ASTM G65 test includes five different tests, 'Procedure A' through 'Procedure E'. The tests differ by how long the test runs except for 'Procedure D', which uses a different amount of weight applied to the wheel.

This test runs on a variety of different materials including plating, hardbanding overlays, hard base materials, and some spray coatings.

(Figure from ASTM G65 spec)

Want to see something we do? Have a question about something?

Let us know in the comments and we will give you an answer or even write about it!

Meet the Staff - John Hadjioannou

Meet the Staff! Once a week for the next couple of months, we will be introducing the people who work here at EPI Materials Testing Group.

This week we will be introducing the man who runs the show here at EPI MTG, John Hadjioannou. John started running EPI Materials Testing Group as the director back in 2006. Every year since, John has expanded EPI MTG's Capabilities, personnel, and clients. Along with handling the business end of EPI MTG, John is a licensed Professional Engineer. He helps clients all over the world with their failure analysis, litigation cases, and other issues.

He has made Quality a top priority of EPI MTG'. Every report that is produced by EPI MTG is reviewed by John. Since John has taken over EPI MTG, the business has continued to expand and garner new clients every year and achieve record revenues almost every year. The BBB (Better Business Bureau) has also given EPI MTG an A+ rating since John has taken over.

ASTM G105 Wear Test

EPI Materials Testing group does custom wear testing and three standardized wear tests for their clients, ASTM G65, G105, and B611. The mass of the test specimens are recorded before and after each test. The mass loss is then converted to volume loss due to the range of densities in materials.

The G105 test is an ASTM 'Standard Test Method for Conducting Wet Sand/Rubber Wheel Abrasion Tests'. Figure one shows you what the test setup is like. The test runs with a 7" steel wheel with a layer of rubber at 50-shore hardness to start with. After the initial test, the test runs again three more times on the same wear scar with a 50-shore hardness wheel, a 60-shore hardness wheel, and a 70-shore hardness wheel, in that order. This test is usually run on Carbide overlays with high hardness values or coating layers made of very hard metals such as titanium. A typical wear scar is shown below (Figure 2).

(Figure 1 from ASTM G105 Spec)

Fig. 2 - Typical Wear Scar

Want to see something we do? Have a question about something?

Let us know in the comments and we will give you an answer or even write about it!

The longevity of a material is very important in the oil industry. With everything that attacks materials in down hole environments, companies have their hands full keeping their tools in good shape. One of the systems that have been in use over the years is hardbanding. Hardbanding is a layer typically added to the outer diameter of drill pipe and other tools. The hardbanding is welded on to the pipe or tool and is usually infused with carbide. These thicker bands around the pipe protect the softer pipe metal from contacting the walls and rocks down hole, thus prolonging their useful life spans. The carbide layer helps make companies drill pipe and other tools last much longer, saving them millions of dollars in the end.

A good way to test and compare these hardbanding applications is with wear testing. EPI Materials testing group uses three ASTM specs and custom testing to help companies get the most out of there hardbanding applications. The ASTM specs are G65, G105 and B611. The three specs all use the same apparatus, but use different wheels, applied forces, duration of the test, and some even use a slurry mix to make the test more abrasive. The test involves sand flowing onto a specimen while a wheel spins against it with a certain applied load. Wear testing has been used to test other materials as well including base materials, thermal sprays, and just about anything else when custom testing.

A picture of typical hardbanding and the wear testing apparatus are shown below.

Want to see something we do? Have a question about something?

Let us know in the comments and we will give you an answer or even write about it!

Failure Analysis - Part 3

Last week we talked about a fracture morphology that exhibited elongated dimples.

Dimples generally form in ductile materials from loads that exceed the yield stress of the material. In these materials, there are inclusions, weak grain boundaries, particles, and cleavage planes. When the material starts to yield, or plastically deform, it starts to form cracks around these particles, inclusions, or at weak grain boundaries. As the material continues to deform, these cracks form into microvoids in the material. The material around these voids continues to stretch creating a cupping effect.

These cupping microvoids are what give the fracture morphology dimples (Figure 1). When the material starts to yield these microvoids expand laterally until they coalesce with other microvoids and form a central crack in the material.

In a torsional load, the microvoids elongate when the material starts to yield (Figure 2). The matching faces of the failure will show the elongated dimples in opposite directions.

The other way they can form is from tearing as shown in Figure 3. The matching faces of the failure will show the elongated dimples in the same direction.

Figure 1 - Microvoid forming froma tension load around an inclusion and what it looked like in the failed state under a Scanning Electron Microscope

Figure 2 - Microvoid forming from a torsion load around an inclusion and what it looked like in the failed state under a Scanning Electron Microscope

Figure 3 - Microvoid forming from a tearing load around an inclusion and what it looked like in the failed state under a Scanning Electron Microscope

Want to see something we do? Have a question about something?

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Failure Analysis - Part 2

Last week I showed you a simple failure analysis of a bolt that had broken into two pieces. Even with EPI Materials Testing Group's experience and knowledge, we like to look at every part of a failure to ensure we have accurate answers and with as much detail as we can find.

So even after looking at this fracture surface with the naked eye, we took a closer look with our stereomicroscope and our Scanning Electron Microscope (SEM).

In this case, a closer look at the fracture surface with our SEM revealed the fracture morphology in detail. When we looked at the morphology, elongated dimples were evident (picture below).

The dimple morphology of a fracture surface indicates a ductile fracture mode. These dimples were elongated which are indicative of shear loading or in this case torsional load.

Next week I will show you how ductile dimples are formed during a failure.

Want to see something we do? Have a question about something?

Let us know in the comments and we will give you an answer or even write about it!

Failure Analysis - Part 1

EPI Materials Testing Group is always trying to get answers for our clients. One of our specialties is Failure Analysis.

Obviously our clients don't want failures in the first place, but we help them solve their problems to prevent future failures. To figure out how something failed we look very closely at the fracture surface.

Below is a basic failure analysis of a bolt that had broken in two.

The fractured bolt failed from rotation and reversed bending occurring at high nominal stress. Which is to say someone pulled from Top to Bottom while trying to tighten then bolt. The dark area at the bottom is where the final tear off occurred.

Next week I will show you the elongated dimples on the fracture surface near the top using our Scanning Electron Microscope (SEM).

Forensic Engineering - Interesting stuff!

Scanning Electron Microscope Sample

We do quite a few things here at EPI Materials Testing Group.

One thing we do quite a bit is taking pictures with our Scanning Electron Microscope (SEM). We are always doing something new, so you never know what you are going to see. Particularly when you are looking at a specimen at 30 times to 10,000 times magnification!

The picture below shows the surface of a metal coupon that had gone though some corrosion testing. Thankfully our client failed to clean the sample off all the way. The picture was taken at 1,500x magnification and the corrosion product on the sample is Iron Sulfide.

It turned out to be one of our favorite pictures of the year!

Happy New Year

Happy New Years from EPI Materials Testing Group!

EPI MTG is proud to announce that we had our best year ever in 2011. We were able to help over 80 different companies and law firms last year!

EPI MTG will strive to make 2012 even better.  Our goals start with assisting our existing and hopefully many new clients with their research and development, failure analysis, and materials testing.

To aid with our goals, EPI Materials Testing Group plans to build a new facility this year!  This will provide the space necessary to expand our capabilities and provide our clients with even more quality services.  The extra space will allow for better service in hosting inspections.  EPI MTG will have laboratory and conference rooms set aside specifically for those purposes. 

We look forward to having another great year and hope that our clients and readers of 'TnT' also have great year!