This standard applies to the ribbed head bolts BM (hereinafter referred to as bolts) used in scraper conveyors in coal mines. MT 187.4-1988 Scraper conveyor fasteners ribbed head bolts type B MT187.4-1988 Standard download decompression password: www.bzxz.net
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Scope of application Ministry of Coal Industry of the People's Republic of China Scraper conveyor fasteners Ribbon head bolts type B This standard applies to the ribbed head bolts type B (hereinafter referred to as bolts) used in underground scraper conveyors in coal mines 2 Reference standards MT187.1 Technical conditions for screws for scraper conveyor fasteners 3 Product classificationbzxz.net 3.1 The products are available in four specifications: M20, M22, M24 and M27. 3.2 See the following figure and Tables 1 and 2 for types and sizes. X Ministry of Coal Industry of the People's Republic of China approved on April 13, 1988 214 MT187.4—88 implemented on August 1, 1988 Basic size Limit deviation Basic size MT 187.4-88 Allowable deviation between screw head and screw centerline, thread finish: Thread blank. Limit deviation L. (including screw tail) and weight of each 1000 steel bolts L Limit deviation Basic size L. Limit deviation of 3.3 Marking example: MT187.4—88 Continued Table 2 L. (including screw tail) and weight of each 1000 steel bolts Weight Coarse pitch ordinary thread, major diameter 20mm, length 70mm, mechanical property 8.8 grade ribbed head bolt type B: bolt M20×70-8.8MT187.4—88 3.4 Marking description: M20×70-8.8 MT 187.4 88 Standard code Performance level Product specification Product name 4 Technical requirements The mechanical properties of the bolts shall not be less than grade 8.8. MT187.4—88 The technical conditions of the bolts shall be in accordance with the provisions of MT187.1. Additional instructions: This standard is proposed by the Technology Development Department of the Ministry of Coal Industry of the People's Republic of China. This standard is under the jurisdiction of the Taiyuan Branch of the Coal Science Research Institute. This standard was drafted by Harbin Coal Mine Machinery Research Institute. The main drafters of this standard are Cong Peijian and Jia Delin. This standard is entrusted to the Taiyuan Branch of the Coal Science Research Institute for interpretation. Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.