1·The wear of piercing punch is one of main die lose efficacy.
冲孔凸模磨损是模具失效的主要形式之一。
2·The test of sulphurized tufftride process for treating the hot piercing punch for steel pipes is introduced.
介绍了钢管热冲孔凸模硫氮碳共渗工艺试验。
3·This paper analyzes main reason why thick sheet piercing punch is easily destroyed, and design a new punch to above-mentioned problem and introduces its some characters.
分析了厚料冲孔用冲头破损的主要原因，针对这些易产生的问题，设计了一种冲头，并说明了其特点。
4·Piercing: refer to artifacts from the ordinary hole punch and mold machining process.
冲孔：指工件由普通冲床和模具加工孔的工艺过程。