Rock drilling rod production line

Steel quality required

It is knew that after researchers long years have been studied the result achieved, in failure analysis drilling rod and whole drilling rod, the steel quality is main reason to effect to drilling rod service life after its geometry parameter reasonable, steel, and production process so the steel quality standard must up to level range.

1)Keep chemical proportion range in steel within <0.015% ( general process elements caused fluctuation <0.05%），，P≤0.014%，S≤0.009%；

2)Hardness difference caused from control steel elements fluctuation and chemical proportion aliquation ≤2HRc (harden ability characteristic range in general process is about 8-10)

3)Keep oxygen content in steel ≤0.0012% ( Oxygen content of general electric arc furnace steel ≤0.004%)

4)Keep D sorts of substance ≤8μm ( in general process they are 40~50μm, specially up to 100μm);

5)Keep steel crystal grain fineness up to 8 class more ( in general process is 4~5 class);

This process achieved on a basic after we analysis of serious production process in domestic and abroad. Its feature:

   (1)To increase the ratio of rolling reduction and good mechanical property of hollow bar, prefer select big diameter billet.

(2)Perfect use big diameter billet to elongate finished hollow drilling rod length and get rate of finish products more;

(3)In this rolling mill, it can roll small sized hollow drilling rods and also can roll heavy one, and can roll heavy thickness pipe, width products range;

(4)Pilling billets, removed billet rolling defect and up drilling rod surface quality more;

(5)With 6 roll rolling forming technique, to make hexangular hollow bar generated compression stress and up products fatigue capability on drilling bar surface;

(6)Compare with drawing process, to adopted 6 roll forming technique, up rate of finish product effectually and reduce production cost;

(7)Compare with other process, it is less investment and lower production cost to guarantee product quality;

Rock drilling rod use hollow steel (GB/T1301-2008)

Graph 1