RU2375142C2 - Method of manufacture of drill rods for drill machines of percussive action - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention refers to machine building, particularly to production of rods for drilling machines of percussive action. The disclosed method of drill rods manufacture consists of following stages: a thick wall tube stock of specified length, thermal treatment and ratio of external diametre to wall thickness is divided to measured sections. Further curvature of measured sections is finished to a process just value; the ends and external surface of sections are subject to mechanical treatment whereupon their ends are heated and deformed to correspondingly specified temperature and wall thickness. Structure elements are cut into sections; the ends are subject to hardening, while a formed section is subject to chemical-thermal treatment by means of nitriding. The feature of the disclosed method is like follows: upon mechanical treatment of ends and external surface of the measured section an internal channel is subject to treatment with abrasive-saturated pulp by means of letting it through the channel at rate exceeding sediment formation ability of abrasive filler of pulp; and after hardening of ends the internal channel is subject to electric-chemical treatment.

EFFECT: upgraded consumer characteristics of drill rods quality in regard to transfer of percussion power, reliability and wear resistance.

3 dwg

Description

The invention relates to the engineering support of the mining industry, in particular as a set of processes that make up the technological basis for the production of drill rods used for underground mining.

Drill rods as a result of the practical implementation of the proposed method are used primarily as part of high-energy saturated drilling rigs for sinking a wide range of mine workings, mining of ferrous and non-ferrous metals, coal, non-metallic materials, also in energy and transport construction, taking into account specific conditions of use and energy support of work drilling machines based on high pressure fluid (from 160 bar).

The specific features of the operation of drill rods in underground conditions include the fact that the volume of mining is millions of tons; rock fortress of 18 or more units on the scale of prof. Protodyakonova; the growing demand of the economy for minerals and the need to address the issue of resource and energy saving while conducting drilling operations identified a rejection of the power supply of drilling machines with pneumatic energy and demanded a transition to drilling rigs based on the energy of mineral fluids with a simultaneous increase in impact energy. According to [1], the shock power of modern hydraulic heads reached 20 kW, while the shock power of the most common drilling machines based on pneumatic energy in the CIS ranges from 2.7 to 6.6 kW and does not exceed 10 kW in the most progressive head 501A - 04/07/0140 [2].

At the same time, pneumatic energy drilling machines of foreign manufacturers also have similar energy indicators.

Therefore, the most famous manufacturers are Atlas Copco (Sweden), Tamrock (Finland), Dailman-Haniel (Germany), Furukawa (Japan), Boart Landler (England) and Gardner Denver (USA) [3, 4, 5, 6, 7, 8 ] limited the production of pneumatic drilling equipment in the range of 15 to 25% of the output and focused on the engineering support of progressive hydraulic drilling using in-house hydraulic drill heads with impact power from 7, 5 [3] to 27.0 kW [8] and drilling rigs based on them. The aforementioned introduced into the production of drill rods a number of technological limitations, primarily related to the increase in the transmission of shock energy by the rod from the hydraulic head to the drill bit. In particular, this relates to bar stock material; their curvature; heat treatment with increasing hardness and corrosion resistance; the exception of hardening and chipping of the ends of the rods; increasing resistance to the influence of alternating torque, impact and action on the “drill-rod-drill bit” system returning from the bottom of the energy (the latter is especially important at the junction of the crown with the rod and rod with the drill head, including using a shank and a sleeve); the cleanliness of the outer surface of its washing channel; elimination of the effect on the reliability indicators of the decarburized surface layer and microcracks of the bar stock; reducing the coefficient of friction of the rod on the wall of the well.

Thus, drill rods are highly scientific and expensive engineering products with mass production - the annual demand for rods of mining enterprises of the former Union exceeded 20,000.0 tons (more than 3 million units); At present, the demand of the mining industry, for example, Ukraine, in these products is 5,000.0 tons (700,000.0 units with an average length of 1.5 m).

The list of characteristic features of the use of drill rods and technological limitations of their production is a base of initial data on the development of technological operations of the method of manufacturing the rods to ensure the use of potential drilling opportunities for blast holes based on hydraulic drilling with an increase in the drilling speed from 1070 mm / min (501A drill head - 04/07/0140 [2]) up to 2000 mm / min and more for breeds with a strength of 14-20 units on the scale of prof. Protodyakonova; achievement of efficiency up to 63% against 9% during pneumatic drilling; increase up to 4 times the resource and achieve the latter up to 1200 spurometers while maintaining the weight and size parameters of the rods.

Known methods for the manufacture of drill rods based on design decisions [9, 10, 11]. According to their technical level of production, these developments have limited use, resource and reliability; the limit of use of these rods is drilling of rocks with pneumatic punchers.

Closer to the claimed method of manufacturing drill rods are the methods according to [12, 13]. The first of them solves the issue of reliability through design and technological support, in which a hollow tube billet is created in the form of three thin-walled tube elements connected into a single unit. In this case, the internal and external elements are preliminarily subjected to heat treatment by hardening, while the medium is technologically provided with an increased viscosity. In turn, the rods according to [13] during their manufacture from solid thick-walled tubular billets are subjected to heat treatment, including quenched with high frequency currents the location of the structural elements of the attachment of the crown and drill head, the outer surface is subjected to shot blasting, phosphating and waxing. The last operation also processes the washing channel.

The method [12] has a complex engineering support, only local security reliability rod; there is no consumer completeness, including structural elements (thread, cone, shoulder, flushing channel).

The method [13] is closer to the claimed one, however, rods made on its basis in connection with the technological absence of descaling operations, washing channel concentrators and in the places where structural elements are formed, as well as the absence of the operation of monitoring and correcting the curvature of the rod blank, have insufficient reliability. In addition, the latter creates operational difficulties at the time of drilling, especially when drilling fractured rocks. At the same time, wear resistance according to the experience of operating drill rods without the above technological operations with structural alloyed drill steel under the mine control of underground ore mining at the ArcelorMittal Kryvyi Rih OJSC (Artem mine) for rods 0.6; 1.1; 1.5; 1.8 m according to the data for 2005-2006, respectively, is 90.0; 72.2; 93.7 and 100 spurometers when drilling with pneumatic drill heads with a capacity of 4.275 kW for rocks with a strength of up to 10 units. by prof. Protodyakonov. Also for these conditions, with limited technological support for manufacturing according to method [13], wear resistance ranges from 574.8 to 295.6 boreholes.

The closest technological solution as a prototype of the claimed invention for its intended use, implementation operations and their sequence, consumer indicators is a method of manufacturing drill rods for percussion drilling machines, which use a hollow cylindrical rod blank of a given ratio of external diameter to wall thickness, produce division blanks for normative-technological segments and their machining are heated by high-frequency currents and the ends of the segments are deformed by pressure to a predetermined temperature and wall thickness, then the structural elements of the connection of the rod with the drill head and crown are manufactured by cutting and subjected to chemical treatment by nitriding in the environment of dissociated ammonia [14].

The disadvantage of the prototype method is the limited area of use of the rods due to the incomplete use of the potential capabilities of structural steel (type 55С2, 28ХГН3МА, 60С2ХФА, 95ХМА), which is a consequence of the non-integrated support for their manufacture. At the same time, the upper value of the shock-energy long-channelized on the bar is limited by the level of 177 J. Analysis of the failure statistics of the rods made according to the prototype method showed that rod breakdown up to 10%, breakdowns in the area of structural elements - up to 85%, breakdowns over cause deformation of the ends - up to 5%. These failures are the result of the lack of technological influence on the inner (flushing) channel of the rod at different stages of manufacture in terms of descaling, limiting the influence of concentrators and scale after the formation of structural elements, and the removal of decarburized layer and microcracks. In addition, the above does not allow full use of the chemical-thermal treatment of the channel.

The disadvantages of the prototype include a limited effect on the control and correction in full (less than 0.15%) of the curvature of the rod stock, the formation of the hardness of the ends of the rod and not taking into account the features of the dynamic effect of impact energy on the contact connection of structural elements with the crown of the drill head, shank and sleeve .

The objective of the invention is the improvement of quality indicators of drill rods in terms of transmission of shock power, increase reliability and wear resistance.

The problem is solved in that in the method of manufacturing drill rods for percussion-rotary drilling machines, a thick-walled pipe billet of a given length, heat treatment and the ratio of the external diameter to wall thickness is used, the workpiece is divided into measured segments, the curvature of which is brought to a technologically justified value, their ends and the outer surface are machined, after which the ends of the segments are heated and deformed to a correspondingly set temperature and thickness ok, structural elements are cut into them, the ends are hardened, and the rod as a whole is subjected to chemical-thermal treatment by nitriding in ammonia and provide the possibility of disconnecting the rod from the crown and the drilling machine during the mechanical operation of the ends and the external surface of the measuring segment the channel is subjected to treatment with abrasively saturated pulp by passing it through the internal channels at a speed exceeding the sediment of the abrasive pulp filler, and after quenching and the ends of the inner channel are subjected to electrochemical treatment in an electrolyte environment.

Thanks to new operations, the influence on the reliability of the rod of defects of the internal channel and concentrators in the field of structural elements is excluded. The above allowed the invention to achieve the solution of the task, namely, it was possible to channel shock energy up to 400 J on a rod with a diameter of 32 mm, which, when the drilling machine was operated with a shock frequency of 50-60 Hz, made it possible to shock the rock being drilled with a power of 20-24 kW. Thus, while retaining the possibility of using rods for drilling on the basis of pneumatic energy, the distribution of the same rods for hydraulic drilling was achieved with a resource of up to 1200 spurometers and a drilling speed of up to 2000 mm / min for the above rocks.

A comparative analysis of the proposed method with the prior art in accordance with the above information sources did not reveal its (level) influence on achieving a positive result according to the task.

Thus, the proposed technical solution meets the requirements of utility, novelty and inventive step, is intended for use in industry, namely in the mining industry, implemented using existing structural alloy steels on existing machine-building equipment, industrially mastered by the metallurgical and machine-building industries, in its own way. quality are import-substituting products, also carried out using recognized science-based methods and with The practical result was achieved in underground mining of ore minerals - the predicted use of rods of the proposed technical level will allow us to reduce the annual consumption of rods by more than three times in conditions of Krivorozhsky Iron Ore Mill OJSC, than the conditions for fulfilling the industrial feasibility that the authors suggested were achieved.

The invention is explained by drawings (Fig.1, 2 and 3) and a description of the technological operations, their place in the implementation of the proposed method.

A measured segment of a thick-walled tubular billet of alloy steel is shown in FIG. 1 as a part of stav 1, inner channel 2 and ends 3. On the surface of stav 1 and inner channel 2 defects 4 occur in the form of microcracks, decarburized layer and scale. Microcracks reach a depth of 0.6 mm, decarburized layer - 0.3 mm. The latter contributes significantly to the fatigue failure of the rods.

мм, круга диаметром 32 мм -

мм.Depending on the type of mining, the type of drilling machine and the required depth of the wells, the lengths of the measured sections should ensure the manufacture of rods for portable perforators from 600 to 3800 mm, telescopic - from 600 to 2600 mm, core and hydraulic - from 1000 to 4300 mm. The preset hardness of the workpiece should be in the range from 34 to 40 HRC with the ratio of the diameter and wall thickness from 3.3 to 6 and the diameter of the inner channel for different modifications of rods from a circle with a diameter of 29 mm -

mm, circle with a diameter of 32 mm -

mm

The implementation of the manufacturing operations of the rods is as follows. First, the measuring segment is subjected to editing on the press equipment, where its curvature is adjusted to a value equal to or less than 0.15%. In this case, the pipe billet comes from a metallurgical plant, as a rule, with a curvature of up to 0.5%, which with a rod length of 4300 mm without this operation will create a deviation of up to 22.5 mm at the point of contact of the drill bit with the rock and, as a result, difficulties drilling In addition, when drilling, an alternating moment occurs, which will lead to premature destruction of structural elements and the becoming of the rod.

Then, during machining, the ends are cut, the chamfers and the curves are sharpened; on the outer surface remove the above defects. The view of the bar stock in this case (after machining) is presented in Figure 2.

To remove defects of the inner channel, at this stage of manufacturing, an operation is also introduced to process its surface with an abrasive-saturated pulp by intensively passing the channel with a speed exceeding the deposition of the filler; using fractions for these purposes due to the insignificant diameter of the inner channel is impractical. As an abrasive, grinding material is used from electrocorundum with a grain size of a fraction from 160 to 2000 μm of a given ratio of fractions, its content in the pulp and the speed of passage; water is used as a liquid.

The value of the speed of passage of the pulp is determined by the expression:

- полная скорость пульпы;Where

- the full speed of the pulp;

V _cr - the critical velocity of the pulp at which the abrasive grains are in suspension;

V _nd - the rate of excess of pulp over V _cr , at which the abrasive moves non-stop by the washing channel, V _nd = (0.15-0.20) V _cr ;

Q - productivity of the supplying pump, m ³ · s ^-1 ;

0,765D _to ² - the cross-sectional area of the channel with a diameter of D _to .

_Lp value V is determined for a particular mass of abrasive grains according to the reference data [P.M.Yaltanets. Design of open hydromechanized and pelleted field development. M., Publishing House of the Moscow State Mining University (MGSU), 2003, S. 353-355].

The next manufacturing process is the heating of high-frequency currents (HD) by the ends of sections 5 and 6 and their deformation, respectively, to a predetermined temperature and wall thickness. In this case, heating is performed over a length of 150 mm with a temperature level of 1150-1200 ° C at a length of 85 mm counting from the end face. Upon reaching the required temperature of the ends of the measuring segment using a universal forging machine (type BZSA, UKMP [2]) they are deformed by extrusion for subsequent cutting of structural elements after cooling. The latter is carried out in two stages: actually cutting and grinding the working surfaces - the workpiece takes the form according to Figure 3.

In this case, the allowance for the diameter of the cone after the first stage is ≥ 0.6 mm, and the preliminary thread diameter is 31.4-31.5 mm. Then perform heat treatment of the ends using high frequency. The heating temperature is 950-1000 ° C over a length of 15-20 mm, natural air cooling. The obtained hardness of the ends 50-55 HRC is optimal, since at lower hardness there is a riveting of the ends, at a higher hardness, cleavage of their surfaces. After heat treatment of the ends, the inner channel is additionally subjected to electrochemical treatment in an aqueous 15-18% sodium chloride solution at a current of 55-60 A.

The last operation allows you to completely clean the inner channel of scale and round off the hubs that occur after the formation of the ends of the rod.

The formed rod preform, purified from defects in the outer surface and inner channel, heat-treated ends, is subjected to chemical heat treatment in a vertical electric furnace in the environment of dissociated (from 30 to 60%) ammonia. The process lasts no more than 20 hours at a temperature of 500-550 ° C, the depth of the nitrogen-saturated layer is 0.8-1.0 mm at a hardness of 78-80 HRC. The cooling of the rods after nitriding is natural and lasts up to 7 hours.

The final step in the manufacture of the rods is to apply brass to its cone (s) by friction brass plating in the presence of a surfactant solution. The transferred layer of brass is 1-2 microns, with a roughness of up to 2.5 microns, the force of disengagement of the cone-crown pair is reduced by up to 2.5 times against direct contact.

The combination of the above technological operations for the manufacture of drill rods and their place in the execution sequence made it possible to use the full potential of drilling alloy steel and achieve the objectives of the invention.

Information sources

1. The new Sandvik Alpha 330 drilling tool system. Mining, 2005, No. 1 (56), pp. 30-31. Email: vadim.day@sandvik.com.

2. Promotional brochures for perforators and drill heads manufactured by Krivorozhgormash OJSC, Krivoy Rog, 2006. E-mail: kzgm@alba.dp.ua.

3. Underground rock excavation Know-how and equipment. Produced by Atlas Copco MCTAB / Roctes Systems, S-10484 Stockholm, Sweden, 2004, p. 75-84. Email: rde@atlascopco.com.

4. Drilling rigs for modern tunneling. TAMROCK brochure, 2004. Tampella Tamrock, SF 33310 Tampere, Finland.

5. Bohrwagen Tour BFR2-235. Dailman-Haniel. Maschinen und Stalbau Gmbh, 2000. Hazemag company brochure (Germany), 2004. E-mail: info@hazemag.de.

6. Furukawa Rock Drill Sales Co. / LTD. Fully hydraulic pneumatic drilling carriages. Furukawa firm brochure, 1989, Cable Address: FURUDRILL Tokyo. Telex: J22402.

7. Drilling shaft installation UBSh-228 with a hydraulic drill from Boart Longler. Mountain Journal, 2005, No. 1.

8. Hydraulic Drill “Hydra-Drill” HPR1H. Gardner-Denver Flyer. Rohoke / Virginia / 24012-8601 USA, tel. (703) 343-1837.

9. SU No. 848567, E21B 17/00, 07.23.1981. Bull. Number 27.

10. SU No. 891885, ЕВВ 17/00, 12/23/1981. Bull. No. 47.

11. SU No. 1079819, ЕВВ 17 / 00.15.03.1984. Bull. No. 10.

12. BRD No. 1229945, E21 C, 12/08/1966.

13. COMET drilling tools. Catalog of JSC “Comet", Finland, 1990, 59 p., P. 10. (telex: 124298 komet sf).

14. UA No. 10725, C23C 8/24; E21B H3 / 04; ЕВВ 19/06, December 25, 1996. Bull. Number 4.

Claims (1)

A method of manufacturing drill rods for percussion-rotary drilling machines, in which a thick-walled tubular billet is used with the given: length, heat treatment and the ratio of the external diameter to the wall thickness, the workpiece is divided into measured segments, the curvature of which is brought to a technologically justified value, and subjected to mechanical processing their ends and the outer surface, then heat and deform the ends of the segments to the correspondingly set temperature and wall thickness, cut into them the design active elements, the ends are subjected to hardening, and the formed segment as a whole is chemothermally treated by nitriding and provides the ability to disconnect the rod from the crown and the drilling machine, characterized in that after the mechanical processing of the ends and the outer surface of the measuring segment, the inner channel is subjected to abrasive treatment of the pulp by passing it in the channel with a speed exceeding the sediment of the abrasive filler of the pulp, and after hardening the ends, the inner channel is subjected to electrochemical tion processing.

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