This standard specifies the product classification, technical requirements, test methods, inspection rules, marking, packaging and storage of seam pipe anchor rods. This standard is applicable to seam pipe anchor rods used for coal mine and other engineering support. MT 285-1992 Seam pipe anchor rod MT285-1992 Standard download decompression password: www.bzxz.net

Coal Industry Standard of the People's Republic of China
Seam-tube anchor
Subject content and scope of application
MT 285-92
This standard specifies the product classification, technical requirements, test methods, inspection rules, marking, packaging and storage of seam-tube anchor. This standard applies to seam-tube anchors used for coal mine and other engineering support. 2 Reference standards
Metal tensile test methods
Carbon structural steel
GB1591
Low alloy structural steel
GB2651
Welded joint tensile test methods
GB2828Batch inspection counting sampling procedures and sampling tables (applicable to continuous batch inspection) GBJ86 Anchor shotcrete support technical specifications 3 Terminology
3.1 Seam-tube anchor: Steel pipe and its accessories specially processed into longitudinal slits. 3.2 Ultimate tensile strength of the rod body: the load when the seam pipe anchor body is pulled apart along the axial direction. 3.3 Pull-out force of the retaining ring weld: the load when the weld between the retaining ring and the pipe wall is pulled apart. 3.4 Initial anchor force: the load when the rod body is immediately pulled out of the rock hole after the seam pipe anchor is installed. 3.5 Pallet bearing capacity: the maximum load before the pallet is compressed and deformed to the specified value. 4 Product classification
4.1 Product specifications and dimensions shall conform to the provisions of Figure 1 and Table 1: 1
1-rod body, 2-tray; 3-retaining ring
Approved by the Ministry of Energy of the People's Republic of China on February 24, 1992 170
Implementation on June 1, 1992
Outer diameter d
Length L
Slit width 6
Head length 1
Head end diameter d2
Dimension aXa
Height h
Aperture d
Recommended drilling diameter
Distance from retaining ring to tail end 1
Note: ①The recommended drilling diameter is for reference only. 10
MT 285-92
1400；
2.2~2.5(16 Mn steel);
2.5~3.0(Q235A grade cold rolled steel）
120×120
② According to the special needs of users, the manufacturer can produce other specifications of the rod body. 4.2 The model and its representation method shall comply with the following provisions: M
Outer diameter, mm/length, mm
Seam pipe type
Example: MF45/1600 indicates a seam pipe anchor rod with an outer diameter of 45mm and a length of 1600mm 5 Technical requirements
150×150
5.1 Seam pipe anchor rods shall comply with the provisions of this standard and be manufactured according to the drawings and technical documents approved by the prescribed procedures. 5.2 The material of the rod body shall preferably be 16Mn steel in accordance with GB1591 or other low-alloy structural steel with mechanical properties equivalent to 16Mn; under the conditions specified in Table 3, Q235A grade cold-rolled steel plate in accordance with GB700 may also be selected. 5.3 The rod body shall be processed by cold rolling. 5.4 Bend the round steel with a diameter of 6.5mm into a retaining ring. When welding, the plane of the retaining ring shall be perpendicular to the rod body and shall be fully welded and flat. 5.5 Appearance quality:
5.5.1 The surface of the seam pipe anchor rod shall be flat, without serious scratches or rust. 5.5.2 The weld shall be free of cracks, pores, slag inclusions, and burning through the pipe wall is not allowed. 5.5.3 The retaining ring interface and the pipe seam opening shall be offset by 170° to 190°. 5.5.4 The tray shall be able to move freely on the rod body. 5.6 See Table 2 for dimensional tolerances:
MT285—92
When d35
When di>35
Rod straightness
5.7The pull-off force of the retaining ring weld, the ultimate tensile strength of the rod, the initial anchor force, and the bearing capacity of the tray shall comply with the provisions of Table 3. Table 3
Rod outer diameter, mm
dj=35~46
Pull-off force of the retaining ring weld, kN
Rod ultimate tensile strength, kN
Initial anchor force, kN/m
Tray bearing capacity, kN
5.8The difference between the borehole diameter and the rod outer diameter shall be selected according to the specific rock conditions and Article 3.3.4 of GBJ86; for a rod with a diameter of 30 mm, the diameter difference shall be strictly controlled, and construction supervision and inspection shall be strengthened. 5.9 When the user has anti-corrosion requirements for the product, the manufacturer shall carry out anti-corrosion treatment on the seam pipe anchor. 6 Test method
6.1 The appearance quality of the seam pipe anchor shall be checked by visual inspection. 6.2 Weld inspection method: Use a small hammer to knock and visually inspect. 6.3 The outer diameter of the rod and the seam width are measured with a vernier caliper at the upper, middle and lower positions of the rod body, and then the arithmetic mean is taken; the length of the rod body is measured with a meter ruler, and the tray size is measured with a vernier caliper. 6.4 Rod straightness inspection method: Place the rod body on the three-level inspection platform and roll it, and use a feeler gauge to measure the maximum value of the gap between the rod body and the platform. 6.5 Pull-off force test of retaining ring weld:
6.5.1 Preparation of test piece: Cut a 200mm long section of the rod body tail and weld the corresponding connector on the end without retaining ring, see Figure 2 for details.3
Figure 2 Pull-off force test piece of retaining ring weld
1 Rod body; 2-retaining ring, 3-connecting head
MT 285-92
The diameter of the large end of the connecting head D=d-28 is the wall thickness). 6.5.2 The retaining ring section is clamped on a special tension frame (as shown in Figure 3), and the specimen connector is clamped in the jaws of the material testing machine. Figure 3 Special tension frame
6.5.3 Measure the pull-off force value according to the method specified in GB2651. For factory inspection, it is allowed to use an anchor tensiometer instead of a material testing machine for testing.
6.6 Ultimate tensile test of rod body:
6.6.1 Preparation of specimen: randomly cut a 300mm long pipe section in the middle of the rod body, and weld the corresponding connectors at both ends. 6.6.2 The test method shall be carried out in accordance with the relevant provisions of GB228. 6.7 Initial anchor force test;
Install the seam pipe anchor in a drilled hole of a rock block or concrete with a uniaxial compressive strength of not less than 40MPa, and the outer diameter of the rod is 2mm larger than the hole diameter (for seam pipe anchor with an outer diameter of 30mm, the outer diameter of the rod is 1mm larger than the hole diameter). Use an anchor tensile tester to measure the maximum pull-out force when the rod body is pulled out and the displacement does not exceed 10mm. The initial anchor force can also be directly tested in the corresponding rock top plate underground. 6.8 Tray bearing capacity test:
Place a simulated retaining ring device above the tray (as shown in Figure 4), place it on a material testing machine and gradually pressurize it, and measure the maximum load before the tray height is compressed by 2/3.
Figure 4 Simulated retaining ring device
7 Inspection rules
7.1 Product inspection is divided into factory inspection and type inspection. Factory inspection is carried out by the quality inspection department of the manufacturer, and type inspection is carried out by the product quality supervision and inspection agency or the unit designated by the competent department. The items for delivery inspection and type inspection are shown in Table 4.173
7.2 Factory inspection:
Inspection itemsbzxZ.net
Appearance quality
Dimensions and specifications
Pull-off force of girth weld
Ultimate tensile strength of rod
Initial anchor force
Bearing capacity of tray
MT 285--92
Technical requirements
Inspection methods
6.1, 6.2
6.3, 6.4
7.2.1 Each batch of products shall be inspected for delivery according to the provisions of GB2828, with 500 pieces as a batch. Inspection categories
7.2.2 The inspection of product appearance quality and dimensions and specifications shall be classified into Class A unqualified and Class B unqualified according to the defect classification a Class A unqualified: including outer diameter and tray aperture. Class B nonconformity: including appearance and general dimensional deviation. b.
7.2.3Use the general inspection level I sampling plan, Class A nonconformity AQL=0.65, Class B nonconformity AQL=2.5, sample size, qualified judgment number A. and unqualified judgment number R. shall comply with the provisions of Table 5. Table 5
As, R included quality level
Sample size
Class A nonconformity AQL=0.65
Class B nonconformity AQL=2.5
7.2.4 Carry out destructive testing on the pull-out force, initial anchor force and pallet bearing capacity of the product retaining ring weld, adopt the special inspection level S-1 sampling plan, AQL-4.0, sample size, qualified judgment number A. and unqualified judgment number R. shall comply with the provisions of Table 6. Table 6
A, R. Qualified quality level
Sample size
Type inspection:
7.3.1 The product shall be subjected to type inspection when any of the following conditions occurs: a.
Product finalization and appraisal of new products or old products that have been trial-produced or transferred to the factory for production; after formal production, if there are major changes in structure, materials, and processes that may affect product performance, normal production should be subject to type inspection every six months, and when the annual output exceeds 400,000 pieces, a type inspection should be conducted every quarter; when the product is discontinued for one year and production is resumed; when the product quality supervision agency makes a request. Type inspection should be sampled from the finished product warehouse of the manufacturer or the products purchased by the user. Each time for type inspection, 10 sets of samples are sampled, and all are inspected for appearance and size specifications; then three sets are randomly selected for pull-off force of the retaining ring weld, ultimate tensile strength of the rod body, and tray bearing capacity test, and two sets are randomly selected for initial anchor force test. 7.3.4 If one item is unqualified in the first random inspection, double sampling will be carried out for a second inspection. If the second inspection is still unqualified, the product is judged to be unqualified.
8 Marking, packaging and storage
8.1 Marking
MT 285—92
Each package should be nailed or hung with a factory label and product certificate on the packing pad or strapping. The label content should include the product name, model specification, quantity, total weight, manufacturer and production date. 8.2 Packaging
When the anchor rod is packaged in pieces, each anchor rod body is 200 pieces and the pallet is 200 pieces, which are fastened with pads and bolts; it can also be packaged in bundles, with 10 rod bodies bundled into a group and 10 pallets bundled into a group. Or pack according to the requirements of the order contract. The packaging must be firm and reliable to ensure that it does not loosen during shipment.
8.3 Storage
When storing seam pipe anchor rods, attention should be paid to waterproofing and corrosion prevention. Additional remarks:
This standard was proposed by the China Coal Research Institute. This standard was jointly drafted by the Beijing Well Construction Research Institute of the China Coal Research Institute and Suzhou Coal Mine Support Special Equipment Factory. The drafters of this standard are Zheng Zhongyuan, Zhang Boqi, Ding Quanlu, and Xu Zhengnong. This standard is entrusted to the Beijing Well Construction Research Institute of the China Coal Research Institute for interpretation.
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