For improving the quality of hot drawn hollowsteeldrill, the total quality control must be adopted though the whole process (from steelmaking to finished product).
文章指出，为了提高热拔中空钢的质量，必须从冶炼开始对全部工序进行质量控制。
2
In order to enhance the service hfe of hollowsteel for rock drill stem, the odd number side section shape hollowsteel has been designed.
为了提高凿岩钎杆用中空钢的使用寿命，设计了奇数边截面形状的中空钢。
3
Common round steel or steel tube may be rolled into solid or hollow twist drill rods by using the said rolling mill.