Final-lab-mag-particle..docx

Engineering Technologies Department Saint John

Student: Michael Smith, Amiee Noel, and Huy Thai Program/Class: Mechanical Engineering/ NDT

Assignment Title: Magnetic Particle Examination V3.1 Due Date: February 14, 2018

“This document is my own work and is in accordance with the NBCC Academic Integrity Policy”

Course code: Mate: 1094

Instructor: Dana Betts

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

Page 1 February 14, 2018

Contents

Lab Objective............................................................................ 2 Equipment List ......................................................................... 2 Specimen: Specimen #1 (Structual Component) ...................... 3 Specimen: Specimen #2: (post) ................................................ 5 Specimen: Specimen #3 (cleat) ................................................ 7 Data Deviation........................................................................ 11 Possible Sources of Error ............................................................ Conclusion ..................................................................................

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

Page 2 February 14, 2018

Lab Objective The object of this lab is to perform a Magnetic Particle Examination to several specimens according to the standards laid out by the ASTM E1444-01 and is used for the detection of surface, or slightly sub-surface discontinuities in ferromagnetic materials.

Equipment List    

Several test specimens: Cleat/Structural Component/Post. Magnaflux powder, 3A Black, Part No-01-1748-81 One adjustable magnetizing yoke. Magnaflux Corp, Model: Y-6, 115V.-60 HZ. Paper Towel

***All tests were done within the valid temperature range 40 °F-125°F.

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

Page 3 February 14, 2018

Specimen: Specimen #1 (Structural Component) Pass / Fail: Fail Number of Defects: 5-10 Number of Suspicious Defects: 3 Further Inspection Required Yes / No: yes (possible repair)

Analysis of Specimen 1: Specimen 1 was made up of one single piece of metal, with different cross sections. Using the magnetic particle examination many different cracks and discontinuities, near the surface of the material were able to be picked up, due to flux leakage, which the magnetic particles were attracted to. A few suspicious spots that got picked up but are not necessary direct failures, however there were 3 spots of possible major failure , that are big stress concentrators. Picking up on these stress concentrators, the part was decided to be failed. Further inspection is required to decide if the part is repairable or not. If part is not repairable it must be destroyed to prevent future use. Since it is a small part could possibly be cheaper just to replace to part, and save the time and cost of further inspection. The following sections will demonstrate the results with comments. The entire part pre- cleaned and demagnetized before examination. A yoke with acceptable magnetic field strength for the ASTM standard was used. Many different readings were taken, at 90 degrees apart to pick up on as much as possible. ASTM E1444-01 standard procedures were followed to ensure for thorough results and accurate testing.

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

Page 4 February 14, 2018

In figure 1 you can see an overhead view of the part before the testing took part.

(Figure 1)

(Figure 2) Defects In figure 2, there are two very noticeable lines, of collections of magnetic particles due to the flux leakage. The two cracks could be detected by visual testing; however by doing the testing we were able to prove these 2 cracks. The cause of these cracks is unknown, possible stress concentrator area.

***continued on next page.

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

Page 3 February 14, 2018

In figure 3, the is another indication from the magnetic particles being attracted to flux leakage, it is a crack and it is near the end of the component, so this is an area that could potential break off. The testing only goes about ¼ to 1/8” of the surface so it may not go deep into the surface but it is possible that it does. Further testing could be done to get more information about the defect. With this test we were able to find and locate these defects.

(Figure 3)

(Figure 4)

(Figure 5)

Suspicious Defects In figure 4 and 5, there are more indications of cracks, as there is buildup of particles. These may not be direct failures, could potential be just light surface scratches. However these could get larger and lead to more serious issues, possible cause could be wear and tear from years of use. Light scratches and dents on the surface are expected to show up as indications. Due to the more major cracks, this part has already been failed.

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

Page 5 February 14, 2018

Further inspection Recommendation

Due to the indications of some severe cracks as well as minor cracks this part is failed. Further inspection could be required, to see if the part could be repaired. However where it is a small smart it may be best to just replace the part to save money and time. Some indications were not serious due to surface wear, but the bigger cracks could not be justified. Most cracks were able to be seen using visual testing but using this method we were able to prove the cracks even further, as magnetic particle examination can go deeper into the material. It gives a better idea of what is going on inside the material.

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

Page 5 February 14, 2018

Specimen: Specimen #2 (Post) Pass/ Fail: Pass Number of Defects: 2 Number of suspicious Defects: 0 Further Inspection Required Yes/No: no

Analysis of Specimen 2: Specimen 2 was made from a round bar of metal with one of the sides ground or cut to a flat surface and two pins on the flattened. By using magnetic particle examination, it was determined that there were no major crack or discontinuities near the surface of the specimen, that would crate flux leakage. There were two false positive readings on the flattened side of the post. With the two-false positive reading and no other major crack or discontinuities found this part has been conceded safe on the surface. Other method of examination should be used to determine if the internal material is safe. The entire part pre-cleaned and demagnetized before the examination. A yoke with acceptable magnetic field strength for the ASTM standard was used. Two readings were taken at 90 degrees apart from each other in the same spot, to pick up on as much as possible. The procedures for the mag-particle examination ASTM E1444-01 was followed to the standard given in class.

Defects As you can see from all five figures below there are no major crack or discontinuities near the surface of the specimen. As you can see in figure 10 the is a build-up of the Magnaflux power around the two pins this is due to the flux lines push the power away from the yoke ends and getting caught on the two pins.

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

(Figure 6)

(Figure 9)

Page 6 February 14, 2018

(Figure 7)

(Figure 8)

(Figure 10)

Further inspection Recommendation Using the magnetic particle examination there were no major failures found on this part, so no further inspection is required. However the magnetic particle examination only picks up defects ¼-1/8’’ into the surface of the part, so could possibly do anther NDT method to penetrate deeper into the surface.

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

Page 7 February 14, 2018

Specimen: Specimen #3 (cleat) Pass/ Fail: Fail Number of Defects: 5-10 Number of suspicious Defects: 0 Further Inspection Required Yes/No: no

Analysis of Specimen 3: Specimen 3 was a complex piece of metal with different cross sections, shapes with different scale and has fair amount of signs of corrosion on the surface. Also, due to the complexity of the specimen, there are noticeable number of defects that are found at near the weld and some cracks, holes are shown on the surface. By using magnetic particle method, most cracks and holes are detected due to flux leakage phenomenon. There are 2 holes on bottom surface below the square socket, also there are a few small cracks that is picked up by particles, and there is a noticeable crack on the weld on the side surface of the specimen. Based on these failure, this part should be destroyed and any further repairing will be waste of time and money. Defects The first two cracks are visible locating on the bottom surface of the specimen and are picked up by attracting particles to the hole. Figure 11 show after applying developer and magnetic yokes, but there are small amount of particles left inside the defects because blowing too hard and remove some of particles out of the hole. These holes are creates by impacting load is applied at concentrated position on the surface.

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

Page 8 February 14, 2018

(Figure 11)

The second defect are found at the bottom surface of the specimen. There are some small indications of cracks which were not picked up at the first test and there are some build up of particle after the second test at 90 degree from the first test. The test can only goes about 1/4 - 1/8” of the surface; therefore, the cracks are small and deep from the surface, particle can be built up in small indication.(Figure 12)

(Figure 12)

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

(Figure 13)

Page 9 February 14, 2018

(Figure 14)

The next defects are easily pick up by both vision and particle build up. First one is open to the surface and attract small amount of particle because the blowing angle of particle does not directly distribute particles on the surface, therefore, there were not many particles are attracted to the crack. The second crack is picked up easily by the particle and it is not open to the surface, because the crack is the testing range below the surface.

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

Page 10 February 14, 2018

(Figure 15)

The last defects are found on the upper surface between 2 circles. There are small below surface crack that the particles are built up and attracted at the crack. They are not open to the surface and are not detected at the first test because in the first test, the current flow is parallel to the defects and the test can not pick up the defects. After the second test on 90 degree of the first test, some defects are starting attract the particles after developer and magnetic yokes are applied

(Figure 16)

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

Page 11 February 14, 2018

Further inspection Recommendation Further inspection is not recommended as this part has many defects and was proved a failed part. Destruction of the part is recommend as any future use would be hazardous.

Data Deviation The Theory of this lab is as followed; magnetic particle examination consists of magnetizing the area to be examined, and applying suitably prepared magnetic particles while the area is magnetized, and subsequently interpreting and evaluating any resulting particle accumulations. Maximum detectability occurs when the discontinuity is positioned on the surface and perpendicular to the magnetic flux. The results proved this theory as particles accumulated around areas of defects because of the flux leakage which the iron particles are attracted too. These indications are a warning sign that there is a defect in the part. In the results of specimen 1 (Structural Component) many different cracks were picked up, and the part was failed, saving time of doing further investigated saving time and money, proving the theory of this lab. Some suspicious readings showed up that were not giving a clear indication, and those indications were tested again to prove if there is a defect there or not. Some discontinuity’s showed signs of being a defect in the part so taking readings at 90 degrees apart verified the defect, as the defect must be 90 degrees in the direction of the flux lines to properly show up. With specimen 2 (Post) the part was passed as no discontinues were found, with magnetic particle examination it is relatively cheap so doing these types of test saves money, as some of the other NDT methods are more expensive. Specimen 3 (Cleat) was failed as many defects showed up in the results many of them being beneath the surface in the ¼- 1/8’’ range. Many cracks and stress concentrators were picked up by doing this test.

Smith, Noel, Thai Magnetic Particle Examination Dana Betts MATE: 1094

Page 12 February 14, 2018

Possible Source of error Applying too much or too little developer resulted in false indications, also not using a gentle touch when applying the developer. Blowing too hard on the developer also caused too much of the iron particles to fall off resulting in no indications at all. The complex geometry of specimen 3 made it hard to see some of the areas of the part.

Conclusion

This lab proved the effectiveness of ASTM E1444-01. There was a large amount of evidence of strong indications of detecting flaws in the parts. Specimen 1 (Structural Component) and specimen 3 (Cleat) were both failed as many defects were detected and the parts were decided to be hazardous, recommended destruction of both parts to prevent future use. Specimen 2 (Post) was passed and decided to be safe for future use. This NDT testing method was able to detect defects in the surface that visual testing and dye penetrant testing would not be able to pick up. This proves the theory of the lab that flux leakage caused by defects in the part causes attraction of the iron particles showing defects in the parts. This lab proved time efficiency as results are fast and accurate and relatively cheap to preform. This lab shows clear indications of presence, locations, and the size of defects in many different parts that are close to the surface ¼ to 1/8’’ deep in the surface.