发明名称 |
ROCKBOLTS MADE OF HIGH STRENGTH STEEL PIPES AND METHOD OF MANUFACTURING THEREOF |
摘要 |
<p>A high-strength steel pipe rockbolt has an expansive rockbolt main body prepared by processing a high-strength steel sheet of 1.8-2.3 mm in thickness with tensile strength of 490-640 N/mm 2 and elongation of 20% or more to a welded pipe and roll-forming the welded pipe to a shaped pipe having one or more concavities extending along an axial direction. Use of the high-strength steel sheet ensures sufficient strength of the shaped pipe regardless of a decrease in thickness. The thin welded pipe is also advantageous in resistance to cracking caused by accumulation of strains introduced during roll-forming, swaging both ends of the welded pipe and hydraulic expansion. Moreover, expansive deformation of the shaped pipe is initiated by injection of a pressurized fluid at a low pressure, so that the expansive deformation is completed in a short time period with an improved working efficiency.</p> |
申请公布号 |
EP1724435(A4) |
申请公布日期 |
2009.09.30 |
申请号 |
EP20040771232 |
申请日期 |
2004.07.29 |
申请人 |
NISSHIN STEEL CO., LTD. |
发明人 |
NAKAKO, TAKEFUMI;YOSHIDA, TAKEYUKI;MATSUBARA, SHIGEO;KITTAKA, TOSHIHARU;KANAZAWA, HIROKI |
分类号 |
E21D20/00;B21C37/15;C23C2/06;E21D21/00 |
主分类号 |
E21D20/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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