A laser scanning welding method for lap joints based on linear energy density regulation includes the following steps 1 to 5. Step 1: welding surfaces of two metal plates of a same material are wiped with anhydrous ethanol; step 2: the two metal plates of a same material are placed in an overlapping manner on a welding operation platform; step 3: a position of a welding focus plane is adjusted; step 4: process parameters of laser scanning welding are set; step 5: parameters of a circular scanning power regulation strategy is calculated and power correction values for the lower plate is set; and step 6: lap welding of the two metal plates of the same material is completed by processing according to the circular scanning power regulation strategy and the power correction values.

A metal bellows for downhole use includes: a bellows capsule with a first end and a second end; an inner diameter side and an outer diameter side arranged between the first end and the second end; where the bellows capsule comprises a first bellows convolution and second bellows convolution and optionally additional bellows convolutions; and each bellows convolution comprises: a root on the inner diameter side of the bellows capsule; a first sidewall extending from the root toward the outer diameter side of the bellows capsule with a first connection point at the distal end; a second sidewall extending from the root toward the outer diameter side of the bellows capsule with a second connection point at the distal end and wherein the second sidewall is on the opposite side of the root as the first sidewall; wherein: the bellows convolutions are formed as a single piece; and the second sidewall connection point of the first bellows convolution is permanently affixed to the first sidewall connection point of the second bellows convolution.