The manufacturers find it difficult to detect the steel pipes with extra deep internal thread groove if they do not meet the relative quality standards.
内螺纹槽超深的钢管不符合相关质量标准，但生产厂却难以检测出内螺纹超深的钢管。
2
The method of two-step core-pulling in forming the component with internal annular groove was introduced.
介绍了成型内置圆环槽结构制品的二步抽芯方法。
3
The system design variables are magnet external diameter of internal ring, internal diameter of external ring, depth of groove - ring and ampere turns.