This review focuses on various aspects of piercing plug surface oxide film, including formation, compose, property, effect, transformation in the piercing course and the influence of plug's life.
概述了穿孔顶头表面氧化膜的形成、结构、性质、作用，在穿孔过程中的变化及其对顶头使用寿命的影响。
It is proposed to get the piercing plug sprayed with a plasma coating in a bid to enhance its surface properties, and thus prolong its service life, and cut down the operation costs as well.
提出采用在顶头上喷涂等离子涂层的方法来提高穿孔顶头表面性能，从而提高其使用寿命，降低生产成本。
Method:Regards ulcer surface size, on ulcer surface the even prompt piercing number needle to dozens of needles. Ulcers with blood covered is appropriate.
方法：先刺溃疡面中央，再沿中央往外均匀点刺数针至数十针（视溃疡面大小），以血溢满溃疡面为宜。
The part quality is hard to reach the product locking requirement when forming the end surface thread after piercing.
用一般先冲孔后压型的方法成形端面螺纹工件，质量很难达到产品锁紧要求。
The study shows that the primary defects on the round billet used for piercing are the sources of screwy surface cracks.
试验结果表明，穿管坯料上存在的原始缺陷是产生螺旋裂纹的内在因素。
Piercing technology for oblique holes on conical surface was analyzed and a new piercing die structure for the conical part was introduced.
分析了锥面斜孔冲裁的工艺，介绍了一种新型的锥形件冲孔模结构。
A layer of ice several miles thick coats its fractured surface, with 1,000 - foot ice cliffs piercing a pitch-black sky.
一层几英里厚的冰川覆盖着它的断裂表面，一千英尺高的冰崖划破漆黑的的夜空。
Steel grades capable for piercing, shell sizes, inside and outside surface quality, wall thickness accuracy and conditions of plug state in use are also described.
对可穿钢种、荒管规格、内外表面质量、壁厚精度以及顶头状况进行了介绍。
Steel grades capable for piercing, shell sizes, inside and outside surface quality, wall thickness accuracy and conditions of plug state in use are also described.
对可穿钢种、荒管规格、内外表面质量、壁厚精度以及顶头状况进行了介绍。
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