During a twist test on a plug weld, what action comes after twisting the top piece off?

• A. Secure in a vise
• B. Twist top piece off
• C. Measure nugget hole diameter
• D. Inspect the fracture surface

Answer: (C)

In a twist test for a plug weld, the key thing you’re verifying is the weld size and fusion after you expose the nugget. After twisting the top piece off, you reveal the weld nugget and the hole it created in the bottom sheet. The next action is to measure the nugget hole diameter to ensure it meets the specified size. This measurement provides a quick, objective check of whether the weld penetrated adequately and filled the joint as required.

Securing the specimen in a vise is a setup step done before twisting, so it isn’t the next action after twisting. Twisting the top piece off has already occurred, so that option isn’t the subsequent step. Inspecting the fracture surface is useful for evaluating how the weld failed, but the immediate, defining check in this test is the nugget diameter measurement; fracture surface inspection usually follows the measurement to assess the fracture after the exposure.