This product is used for rope coring drilling that can coring without raising bit or lesser raising bit frequency than other drilling methods. This method can obtain the core with the special steel rope fisher that through the centre hole of drill pipe to raise the core from bottom of the inner pipe to ground rather than raising all of drill stem to obtain the core.
Rope coring drill pipe is represented by C, including universal type（S）, enhanced type（P）and thin-wall type（M）.Universal drill pipe directly processing the connection thread on both ends of pipe；Enhanced drill pipe first processing the pipe ends then processing the reinforce connection thread；Thin-wall drill pipe is made of special thin-wall pipe material that ends be internal upsetted.
The main materials or grades
ZT380、ZT 490、ZT 520、ZT 540、ZT 590、ZT 640、ZT 740。
Executive standard（The corresponding national standard, American standard, European standard, Germany standard, Japanese standard, and the enterprise standard）
GB/T 9808-2008《Seamless steel pipe for drilling》
JIS G 3465-2006《Seamless steel pipe for drilling
GB/T 16950-2014《Geological core drilling tool》
Tensile strength Rm/MPa
Notes：a Yield strength of Grade ZT520 is measured by Rp0.5.
OD tolerance：-0.5%D~+1.0%D，WT tolerance：-10%S~+12.5%S，Straightness：≤1.0mm/m
This product is mainly used for transmitting drilling power and transporting mud which should have good strength, ductility, tenacity, high wear-resisting, anti-fatigue reverse and corrosion resistance.