What angle tolerance would classify a fusion face as skewed?

• A. Fusion faces with angles under 60deg and over 120deg
• B. Fusion faces with angles under 30deg and over 135deg
• C. Fusion faces with angles between 30deg and 135deg
• D. Fusion faces with angles exactly 90deg

Answer: (B)

The angle tolerance being tested is how much misalignment of the fusion faces is allowed before it’s considered skewed. Fusion faces should meet with an angle that keeps enough edge contact for proper fusion and a stable weld geometry. If the included angle falls below 30 degrees or above 135 degrees, the faces are too misaligned for reliable welding, so that condition is described as skewed. Keeping the angle within a 30 to 135 degree range ensures the joint can be welded with proper fusion and penetration. For example, a joint with about 20 degrees would have very little edge contact, increasing the risk of lack of fusion; a joint around 140 degrees would be poorly aligned for proper fit-up and weld integrity. Therefore, skewed is when the angle is outside the 30–135 degree range. Angles like 60, 90, or 120 degrees are acceptable.