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NICK BREAK AND FRACTURE TEST Objective: This experiment covers test method for break test on butt weld and fillet weld and examines the surface for weld area. Break test involves breaking the weld joint to examine the fractured surfaces for external defects. The nick break test is useful for determining the internal quality of the weld metal. This test reveals various internal defects (if present), such as slag inclusions, gas pockets, lack of fusion, and oxidized or burned metal. Procedures: 1. To accomplish the nick-break test for checking a butt weld, the specimen preparation was began by cutting using plasma cutting. 2. The important thing in this test is the bevel preparation. At the edge of the specimen should be machined by using milling machine that has been set to 45 o . 3. The bevelled need to be clean surface and the angle of the bevel must be 45 o . 4. We used FCAW as the welding process to join the specimen. 5. The test specimen shall be cut transversely to the welded joint and shall have the full thickness of the plate at the joint. This was shown by the figure 2 below. Figure 2 Specimen has been cutted
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Page 1: Nick Break and Fracture Test

NICK BREAK AND FRACTURE TEST

Objective: This experiment covers test method for break test on butt weld and fillet weld and examines the surface for weld area. Break test involves breaking the weld joint to examine the fractured surfaces for external defects.The nick break test is useful for determining the internal quality of the weld metal. This test reveals various internal defects (if present), such as slag inclusions, gas pockets, lack  of  fusion,  and  oxidized  or burned metal.

Procedures:

1. To accomplish the nick-break test for checking a butt weld, the specimen preparation was began by cutting using plasma cutting.

2. The important thing in this test is the bevel preparation. At the edge of the specimen should be machined by using milling machine that has been set to 45o.

3. The bevelled need to be clean surface and the angle of the bevel must be 45o.4. We used FCAW as the welding process to join the specimen.5. The test specimen shall be cut transversely to the welded joint and shall have

the full thickness of the plate at the joint. This was shown by the figure 2 below.

Figure 2 Specimen has been cutted

6. Make a saw cut at each edge and at the surface through the center of the weld. The depth of cut slot should be refer to the lowest weld bead as long as all the welded joint have been sawed as shown from figure 3 below.

Figure 3 Specimen from side

Saw slot

Page 2: Nick Break and Fracture Test

7. Next, place the saw-nicked specimen on two steel supports, as shown in figure 4 below. But in this experiment, we us same method as bending test equipment. The only different that we have done is the test specimen was placed with the surface face upward.

Figure 4 Nick-break test position

8. Applied the force using testing machine onto test specimen.9. The forced should be applied until the test specimen break or fracture.

Result:

From the figure 5 below, it’s show the result of the nick break test. The applied forced that have been applied when the specimen break have been taken.For the first applied force, the gauge indicated at 400psi and the specimen was turn backward and the second applied forced that make the test specimen break is at 200psi.

Figure 5 Test result

Surface

Page 3: Nick Break and Fracture Test

The fracture surface is then examined either by using eyes or hand. The type and location of any weld defect have been spotted internal defects such as:

(i) Gas pockets (ii) Slag inclusions (iii) Porosity.

We also have spotted corrosion that has been propagated in the weld joining.

Discussion and Conclusion:

From what we have achieved from the experiment, it shows the internal defect that occurs in the weld joint as the results that have been spotted. The weld penetration also not deeper and this is shown by the applied force before the test specimen break.

This is because of the welding preparation including the bevel preparation and also involved welding technique. The corrosion also occurs in the break structure. This is because of the oxidation and to avoid that, the test specimen should be test immediately after been prepared. The other effect is the slag that not been removed after the weld run and this will result gas pocket and porosity. To avoid that, the slag should be removed after every weld.

References:

1. Nick Break, Weldability, ASTM, TCR Engineering Services, Material Testing Laboratory

2. Nick Break Test