Nitrogen Protection is used in practical industry because of poor wettability of lead-free solder.

由于无铅钎料润湿性较差，在实际生产中普遍采用氮气保护。

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Experimental results show that lead-free solder paste in the poor mobility of steel line, resulting in deposition area, volume and height of the maximum and minimum fluctuation is obvious;

实验表明，无铅锡膏在钢网上的流动性很差，导致沉积面积，体积和高度的最大值和最小值的波动变化十分明显；

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