So often easily design overflow and air vent at inappropriate location, making casting generated gas hole.

所以常常容易因为溢流井与逃气道位置设计不当，使得铸件产生气孔的缺陷。

By adopting blowing side protective gas, the problem that gas hole was easy to form owed to evaporation of zinc and moisture of circumstances in laser…

结果表明，在侧吹保护气体的条件下，激光深熔焊接能有效地避免高强度镀锌钢热影响区的软化和控制焊缝气孔及焊接接头裂纹的产生。

It is significant to improve the hydraulic system for better performance of drilling rig and the higher ratio of finishing gas hole.

提高全液压坑道钻机液压系统的技术水平，对于改善钻机整机性能及提高瓦斯抽采孔的成孔率具有重要意义。