When welding butt joints with arc welding, the gap size and the type of bevel are usually determined based on the thickness of the welding plate. Under certain conditions, the larger the size of the bevel or gap, the smaller the excess height of the weld bead produced, which corresponds to a decrease in the position of the weld bead, resulting in a reduced fusion ratio. Therefore, leaving a gap or creating a bevel can be used to control the size of the excess height and adjust the fusion ratio. Compared to not leaving a gap, the heat dissipation conditions for a beveled joint are somewhat different; generally speaking, the crystallization conditions for a beveled joint are more favorable.

When the welding wire is tilted forward, the effect of the arc force on the molten pool metal being pushed backward is weakened, causing the liquid metal layer at the bottom of the molten pool to thicken, the penetration depth to decrease, the depth of the arc's penetration into the weld flange to reduce, the range of the arc spot movement to expand, the weld width to increase, and the excess height to decrease. The smaller the forward tilt angle α of the welding wire, the more pronounced this effect becomes. Conversely, when the welding wire is tilted backward, the situation is the opposite. In stick arc welding, the method of backward tilt is often used, with the tilt angle α between 65° and 80°.