通过采用多种无损检测方法对船体焊道打底层微裂纹缺陷检出率进行对比分析和应用，从实用性和有效性两个方面确定了对焊接过程和完工后焊缝检测方法的研究和选择，最终优化了检测方法;并且消除和避免了大量裂纹类缺陷的存在，确保了焊接产品的完工质量，提高了船体的整体安全性。

Multi-NDT methods were introduced into analysis and evaluation of the detectable rate of crack-like indications on the root pass of welds. The NDT techniques were optimized from practicability and reliability by using welding progress and the welds being completed. Most of crack-like indications were eliminated so that quality and the security of the Hull was assured based on the integrate NDT methods.