Which of the following methods is recommended to prevent cylinder warping during welding?

Applying short welds on opposite sides of the cylinder is recommended to prevent cylinder warping during welding. This method helps distribute the heat evenly across the material, thereby reducing the risk of thermal deformation. When heat is applied to metal, it expands. If one side of a cylinder heats and contracts more than the other side, it can lead to warping or distortion.

By placing short welds on opposite sides, the expansion and contraction are balanced, minimizing the stress that could lead to warpage. This technique helps maintain the integrity of the cylinder's shape throughout the welding process. It allows for more controlled heating and cooling, which is essential for maintaining dimensional stability.

Other methods, such as continuous welding, can increase the risk of heat concentration in one area, making warping more likely. Using a heat sink might help absorb some heat, but it may not provide the same level of control in balancing heat distribution as alternating short welds. Working with cold metal is not practical in most welding applications, as preheating can be necessary for proper joint fusion, especially in thicker materials.