Many forces acts on the weld puddle with different welding conditions.
Swirling motion of weld puddle can be more often seen precisely with autogenous arc welding process.
This swirling motion ensures proper fusion of edges of the weld joint.
This can be more observed in PAW and GTAW process.
The fillet weld break test is a mechanical testing process for examining the root penetration in a destructive manner. While the macro-etch test provides penetration depth of the specimen in a given area, the fillet weld break test examines the root penetration for the entirety of the specimen. The test includes the potential failure points of the weld which are the stop and restart of the weld.
To pass the break test, the specimen must bend flat upon itself without fracturing. Should fracture occur, the fractured surface shall show no evidence of cracks or incomplete root fusion, and the sum of the lengths of inclusions and porosity visible on the fractured surface shall not exceed 3/8 in (10 mm) in Figure as shown below,
Break Test Procedures
- Cut 25 mm off of each end of the 150 mm specimen resulting in a 100 mm specimen (the 25 mm Specimens will be used for the macro etch test)
- Be sure the table is clear of all obstructions
- Place the T joint on an angle with the weld metal face up as shown in Figure, subjecting the root of the weld to tensile stress
- Drop the press on the material until the specimen breaks or lays flat on itself
- Examine the results
The macro-etch test will be utilized to gain a penetration reading of each test specimen. The macro-etch test allows for the observation of the weld penetration profile by sectioning the weldment. The profiles will be observed for the effective throat depth. The information will be recorded to verify the acceptance and integrity of each weld performed from a penetration stand point. The results will be compared with the results from the mechanical testing processes (i.e. break test) to help define the failure limits of various penetration depths.