Abstract The seam welding sample for auto oil tank is adopted as example to illustrate the features of nuggets of resistance welding via the use of saturated water solution of picric acid.

• 摘要 以汽车油箱缝焊样品为例，采用苦味酸饱和水溶液可以比较好的显示一些电阻焊的焊核形貌；真实熔合线位置显示清晰，便于观察、测量。