In a basic fillet weld, how does increasing leg length affect strength and what is a potential drawback?

In a basic fillet weld, how does increasing leg length affect strength and what is a potential drawback?

• A. Leg length does not affect strength.
• B. Leg length only affects appearance.
• C. Increasing leg length decreases weight.
• D. Increasing leg length increases throat thickness and strength, but excessive size adds weight and distortion.

Answer: (D)

In a fillet weld, the strength is tied to the throat thickness—the shortest distance through the weld from root to face. When you increase the leg length of a fillet weld, the throat thickness grows (for a typical 90-degree joint, throat ≈ leg length × sin 45° ≈ 0.707 × leg length). A thicker throat can carry more load, so the weld becomes stronger. But if the weld is made too large, the extra heat input can cause distortion or warping of the joined parts, along with more weight, material use, and potential fatigue issues. So increasing leg length increases throat thickness and strength, but excessive size adds weight and distortion.

In a fillet weld, the strength is tied to the throat thickness—the shortest distance through the weld from root to face. When you increase the leg length of a fillet weld, the throat thickness grows (for a typical 90-degree joint, throat ≈ leg length × sin 45° ≈ 0.707 × leg length). A thicker throat can carry more load, so the weld becomes stronger. But if the weld is made too large, the extra heat input can cause distortion or warping of the joined parts, along with more weight, material use, and potential fatigue issues. So increasing leg length increases throat thickness and strength, but excessive size adds weight and distortion.