Briefly in the mine hoist rope What are the requirements for the job
Many domestic production of advanced technology to master the rope business, production capacity, technical level and gradually move to the international. It has been with the production of high strength, high toughness, low relaxation, uniform quality rope twisting ability. Production of steel wire rope, bending fatigue performance may be controlled, and meet the design requirements; structural elongation, reduction of area to meet the design requirements; the whole rope breaking force to meet the specification requirements, and uniform twisting tension between the inside of each strand rope ; oil content of hemp core meet the lubrication requirements of steel wire and so on. Rope making process, the configuration of scientific rope diameter and wire diameter, wire rope and rope diameter Once the structure, the size of the wire diameter can be accurate to 0.01mm between the wire and the wire, the gap between the stocks and shares to control the number of; grain size wire standardization requirements; hemp core radial compression rate standardization; rope splits do under mechanical properties test monofilament, its tensile strength steel, repeated bending and torsion value value, meet specification conditions, uniform control within a certain range.
Accounting for more than 90% of the survey group of large coal mines, coal is not very understanding of the domestic steel wire rope existing standards, the survey found. The purchase of wire rope not in accordance with current norms, in line with mine own conditions proposed technical requirements, and use the rope century 70 to 80 years flag code specification (ie, well construction wire rope specification selected models) requires the purchase of lifting rope. Such as: coal mines to enhance personnel, before 1996, the coal industry specification using special class rope; since 1996, the national standards, industry standards have to switch to coal important uses wire rope, galvanized if requested, you must use a Class AB or Class B galvanizing. Mine when the company proposed purchase rope requirements still require special class, galvanized. Wire rope manufacturer in order to facilitate production, reduce costs, to the coal mines to provide Class A galvanized steel wire rope. Some companies provide general use wire rope coated wire rope to the coal mines, coal mine drill string do not understand the current standard of loopholes.
Classification purposes, the intensity level, toughness index, so differences between grade galvanized wire rope production execution "GBT8918-1996 Rope" and "Century 70 ~ GB1102-74 round strand rope 80's" "YB829 ~ 79 Shaped shares rope "and other norms vary widely. Both can go on comparison. Principles Mine rope technicians or management personnel, the mine hoisting rope through a qualified inspection agency, inspection or not, based solely on whether the suspension of use, do not know how qualified do not necessarily meet the technical requirements for use of the mine . A significant number of multi-rope friction hoisting auxiliary shaft (lift personnel or material) to purchase Class A galvanized steel wire rope, with a test due to be determined in accordance with AB class when people mention. Wire rope manufacturer, according to the requirements of Class A galvanized inspection agency inspection, issuance of Class A galvanized inspection acceptance speech. However, two kinds of types of galvanized wire rope toughness index difference between the larger, anti-bending fatigue performance differences, some strength is also a great difference. Mine get a qualified inspection agency issued the inspection speeches, safe to use, totally do not know has been planted to enhance mine safety problems.
Wire tensile strength, repeated bending and twisting wire low total number of three trials allowed, "Rule" and "MT716-1997 Coal important uses wire rope inspection and technical conditions" requirement. The total cross-sectional area than the test wire and low total cross-sectional area of ​​the wire is calculated, 6% can not be used as lifting personnel; 10% can not be used as lifting materials.
Already below or behind the "GB / T8918-1996 rope" on the low wire requirements, 6% and 10% of the value requirements. Specific data in Table 619 + Fc-21.56V21 + Fc-226V37S + Fc-39.5 rope 1 listed as an example.
Press the "GB / T8918-1996" do the mechanical properties of the monofilaments 100% stock split test, the widespread use of coal mine shaft lifting long triangular strand wire rope. The triangular strand wire rope. The number of wires that allows a low, equivalent to a total break with the test area than the low steel wire total cross-sectional area of ​​between about 3.85% - 6.84%, less than or close to 6% if all of the inner layer of fine wire low silk, the ratio of the total cross-sectional area of ​​the wire test low total cross-sectional area of ​​the wire between 3% to 5%, less than 6% if all of the low steel outer thick wire, the low value of the total cross-sectional area of ​​the wire wire test than the total cross-sectional area of ​​between 6.42% - 6.84%, close to 6% less than 10% and therefore, Allow low ratio of the total cross-sectional area of ​​the wire and the wire test total cross-sectional area of ​​not less than 10% of the claims, "4 of order" and MT716-1996 to extract the wire rope 100% stock split test. Even lower than the "GB / T8918-1996" the number of low-value steel allowed, converted into low-value ratio of the total cross-sectional area of ​​the wire the total cross-sectional area of ​​the wire test at 3.85% - 7.83% requirement.
Upcoming implementation "GB8918 important uses rope" can not correspond. The revised "GB8918 important uses rope" of international norms "ISO3154-88 mine hoisting rope delivery technology" for the rope above requirements and more stringent than the "GB / T8918-1996 rope" to or more stringent than the higher "MT716 -1997 "specification. "Rule" and "MT716-1997 norms" and "low in 2003 revised finalized."
Wire rope demolition do an off monofilament, bending, twisting three trials; rope (whole rope) breaking force test. Its tensile strength steel allowed value, the upcoming implementation of the "GB8918 important uses rope" requirement. Control between the lower and upper and lower limits of the nominal tensile strength, tensile strength of the upper limit for the public shift plus 260290320350MPa unequal (different wire diameter applied with different values) than the "MT716-1997" allows the wire tensile strength values , the lowest increase 50MPa highest increase 400MPa repeated bending, torsion allowable value than the "MT716-1997" requirements have been increased. Increase the amount of rope elongation structure requirements. Limited rope elongation structure, reducing the process of ascension are installed, uninstall the parking position is not accurate, reducing the time to enhance the cycle time; eliminate slipping rope friction hoist multi-emergence of discontinuity, skipping and other security risks significant.
Coal industry standards for low wire requires less than international norms
The tensile strength of steel wire rope allowable value of nominal tensile strength of 50MPa minus international norms ISO3154-88 mine hoisting rope delivery technology "for the tensile strength of steel wire rope in the requirements of the nominal tensile strength of the lower limit, "MT716-1997" specification. The upper limit for the nominal tensile strength plus 260290320350MPa unequal (different wire diameter applied with different values) than the "MT716-1997" required minimum tensile strength steel to improve 50MPa highest increase 400MPa Therefore, the coal industry before the suspension of imports of steel wire rope to do test execution MT716-1997 norms, reducing the coal mine on imported steel wire rope lifting requirements.
Wire rope inspection program is less than the national specification.
Condition determination is qualified to do the wire rope stock split monofilament test the mechanical properties of the coal industry, wire rope inspection. That tensile wire repeated bending and torsion tests. Three test results meet regulatory requirements, judged to be acceptable; otherwise deemed to have failed.
"GB / T8918-1996" and "MT716-1997" are on the rope diameter tolerance and roundness, weight per meter, cord, twisting quality, oil-coated made quantitative or qualitative requirements.
Specification does not include coal mines to enhance theoretical and practical requirements for wire rope
The larger the diameter of the rope groove, multi-rope friction rope grooves enhance the general requirements are not more than 0.05mm in diameter tension otherwise imbalance will be very obvious. Its upward side of greater tension, the tension lowering side smaller. "GB / T8918-1996" and "MT716-1997" rope wire rope diameter variation are defined as nominal diameter 0 ~ + 6% multirope friction in most wire rope diameter d = 21 ~ 40mm If the rope diameter d = 21mm + 6% deviation 1.26mm0.05mm25 times; if the rope diameter d = 40mm + 6% deviation 2.40mm0.05mm48 times. Multirope friction process, the rope is the ride on the rope grooves, rely on the friction between the rope and the rope grooves driven lift lifting or delegated to the container. If the rope groove diameter deviation meet the requirements, high tension wire rope diameter deviation imbalance will be very obvious.
That bias control within a predetermined value for a small coal multirope friction if the requirements of the mechanical properties of each rope, elongated structure, rope diameter, reduction of the same. The process of ascension tension imbalances will be effectively controlled. For years, researchers tension imbalance, experts and scholars have always believed: rope tension caused by the uneven distribution of the main factors are three kinds, ① unequal lengths of rope; ② different each rope rigidity; unequal ③ pulley rope groove diameter. The impact stiffness coefficient ranging from rope and rope diameter variation caused negligible. Because the "Rule" requires replacement of the rope at the same time necessary to replace all of the main rope, wire rope should be the same size, the same batch of products, the deviation of each rope stiffness values ​​can actually control in a small range. Therefore, we should consider the rope groove radius deviation and rope suspension length deviation caused by the impact. However, coal enhance peace sign with rope inspection, acceptance testing, inspection before the suspension, did not put forward rope wire rope diameter variation, structure elongation, reduction of area (ie the force rope after rope diameter rate of change) and rigidity requirement coefficient. Survey, the results of testing to prove an indisputable fact, the same public suspension while using said plurality of wire rope diameter, the diameter of the suspension after the force variation is large and elongated structure also varies widely; with a length of rope in 100 meters within the appearance of size, performance, there are differences.
In order to solve the structure of the rope elongation capacity, the coal industry, science and technology workers. Parking position can not be accurately problems had developed a skip hoisting lift loading and unloading apparatus, the floor of the cage lift device, multi-rope friction hoisting cable tension brake adjustment device, and so on. Some Coal Mine Group, or the use of imported steel wire rope master, auxiliary shaft hoist in order to reduce the above-mentioned problems in the process of ascension.
And the structure of each rope elongation, reduction of area, of the same diameter (error as small as possible) rope, multi-rope friction to enhance coal mine can be used if high strength, high toughness, low relaxation, even twisting quality. Then the multi-rope friction hoisting cable tension imbalances, it is likely to be radically curbed, thereby reducing or eliminating the process of lifting the rope slip, card cans, broken rope even lower container fall well accidents. At the same time extend rope life and reduce the amount of maintenance care of themselves. Today the coal industry to enhance the wire rope requirements still remain in the only required mechanical properties of steel filaments level.
Mine awareness of the wire rope is not comprehensive
Whether the supplier can provide mine safety certification mark, as ordered basis; Mine rope units and responsible person, Coal Mine Group in the purchase of wire rope. The rope suspension before after inspection by a qualified inspection agency, as the sole basis for the use of safe and reliable. When shopping for a certificate of quality rope Supplier of whether to meet the requirements for mine hoisting rope does not recognize; Compliance Content for qualified inspection agencies inspection of speech, whether complying with the terms of mine will not be judged. However, peace sign test, suspension test before, only to do the wire rope stock split tensile strength, repeated bending and torsion tests, that the mechanical properties of the monofilament satisfies the relevant provisions of the standard test is performed.
Wherein the local rope appearance of poor quality, such as: a Coal Mine Group from 2002 to May 2003, nearly a hundred article submission rope. Strength quality certificate does not meet the stated requirements of the standards, some no production date, delivery date, delivery date beyond some acceptance test specification time. Inspection body according to GB / T8918-1996 demolition wires that an acceptance testing, acceptance testing issued a qualified speech. Despite Coal Group wire rope inspection staff, poor appearance quality rope objection, but qualified inspection agencies have determined that the rope had agreed to use suspension. Rope author after follow-up survey, the quality certificate does not comply with current regulatory requirements, the use of less than six months had to replace Another example: a coal mine inspection group 11 619 + Fc-21.518.5 cord with 10 quality certificate marked for general use. Inspection according to GB / T8918-1996 as a general purpose rope determination nine qualified. "Rule" and "MT716-1997" provide that coal must be used to enhance the important uses rope. The coal mine approved such a test, and there is no objection by the mine ascension. This nine ropes, there is a rope hanging on the third day of use, broken rope car, resulting in a rollover drop extracts tub track, no casualties.
You should be familiar with and master the international and domestic wire rope science and technology development, the coal industry to do a specific work of experts. So that the coal industry to enhance the standard wire rope and "order" to enhance the wire rope requirements, to keep up with international and domestic wire rope industry's technology level.
Participate in national standard wire rope system, revision. Coal transport to enhance theoretical and practical, the coal industry to do specific work of experts. Wire rope requirements written into the national standard, written into the coal mine hoisting rope industry standard. Let rope manufacturer to master the coal mine lift wire rope requirements.
Personnel mines with a rope, Coal Mine Group to purchase rope staff. To promote its current national norms rope and coal industry standards, promote its rope theoretical knowledge. Mine rope to lift transport industry to promote its theoretical and practical requirements for wire rope.
Solutions to enhance the uninterrupted control of coal mine problem in the transport rope, wire rope lifting coal mine industry standards and revision specialists. With rope industry can understand and accept the language, the problem back to the rope industry.