Mechanical Industry Standard of the People's Republic of ChinabzxZ.net Steam Turbine Pipe Accessories Subject Content and Scope of Application This standard specifies the size series and basic requirements for screw plugs for steam turbines. This standard applies to the design, manufacture and acceptance of screw plugs for steam turbines. 2 Reference Standards GB1220 GB3077 Basic dimensions of thread finish, shoulder distance, undercut, chamfer for ordinary threads Ordinary threads Tolerances and fits Stainless steel bars Technical conditions for alloy structural steel GB3103.1Tolerances for fasteners Bolts, screws and nuts JB2901 Technical conditions for anti-rusting of steam turbines Structural types and sizes Inch series The structural type and dimensions of the hexagonal screw plug are shown in Figure 1 and Table 1. 3.1 Printing part Hexagonal head length ——Plug depth W—Chamfer radius Flange length d—Aperture -Hexagonal width across flats Mark: Name Thread specification standard number Example: Screw plug M10×1JB/T6296.7-92 Ministry of Machinery and Electronics Industry Approved 199206-26 Shoulder distance of undercut Major thread diameter Hexagonal diagonal dimension Chamfer dimension Outer diameter of flange JB/T6296.7-92 Thread length Diameter of undercut Implemented 1993-01-01 M12×1.26 M27×2 M30×2||tt ||M33×2 M39×2 M42×2 M45×2 M48×2 M52×2 M56×2 M56×4 M64×2 M76×2 M76×4 JB/T6296.7-92 3.2 For the structural type and size of the venting vortex, see Figure 2 and Table 2. min per 100 pieces flange thickness -vent hole diameter marking:namethread specification JB/T6296.7-92 figure, 2 retract diameter flange diameter plug length thread major diameter -plug depth -vent hole center to plug end face size standard number example: vent plug M14×1.5JB/T6296.7-92 table the structural type and size of hexagonal spiral pipe are shown in figure 3a, figure 3b and table 3 inner hole diameter inner hole Depth Weight per 100 pieces Hexagon depth Major diameter of pipe thread Length of pipe plug JB/T6296.7-92 Mark: Name Taper thread Size code Standard number Retracting phase diameter Example: Hexagonal spiral pipe plug MPT1/8JB/T6296.7-92 Table 3 Taper thread Size code NPT1/8 NPT1/4 NPT3/8 NPT1/2 NPT3/4 NPT11/4 NPT11/2||t t||3.4 The structural type and size of square head spiral pipe plugs are shown in the figure. Printing part Major diameter of tapered pipe thread Length of square head Flaring diameter Width across flats Spiral length Diagonal size Weight per 100 pieces Orifice—Square head side length Marking: Name Thread size code Standard number JB/T6296.7-92 Example: Square head spiral pipe plug NPT1/8 JB/T6296.7-92 Table 4 Tube thread size NPT1/8 NPT1/4 NPT3/8 NPT1/2||tt| |NPT3/4 NPT11/4 NPT11/2 NPT21/2 NPT31/2 For the structural type and dimensions of square head screw plug (ZG), see Figure 5 and Table 5. 3.5 Printing position 1.5×45° Major diameter of taper pipe thread H Square head length Marking: Name Taper pipe thread size code Standard number Example: Square head screw plug ZG1/8JB/T6296.7-92H Spiral length Weight per 100 pieces 200:17 Side length of a square head Taper pipe thread size ZG 1/4 ZG 1/2 ZG 11/4 ZG11/2 ZG 21/2 ZG 31/2 4Technical requirements JB/T6296.7-92 Material selection and heat treatment requirements shall be as per Table 6 and shall comply with relevant standards. Table 6 Parts Name Hexagonal screw plug Vent plug Hexagon socket Screw pipe plug Screw pipe plug Square head screw plug Carbon steel Alloy structural steel Alloy structural steel Carbon steel Carbon steel Stainless steel Carbon steel Stainless steel 15CrMoA20CrMoA 35CrMoA 20Cr1Mo1VNbTiB||tt ||25Cr2Mo1VA OCr19Ni900Cr19Ni11 00Cr19Ni11 GB3077 GB3077 GB1220 GB1220 Weight per 100 pieces 311.30: Solid solution + aging Solid solution + aging 4.2 The basic dimensions of the threads of hexagonal screw plugs and venting swivel plugs shall comply with GB196; the thread tolerance shall be manufactured according to the 6g6H grade specified in GB197. 4.3 The verticality between the bearing surface of the screw plug and the swivel plug and the thread center shall comply with GB3103.1. 4.4 The tolerance of the width across flats of the inner and outer hexagonal plugs shall comply with GB3103.1. 4.5 The unmarked thread undercut, tail and chamfer shall comply with the provisions of GB3. 4.6 Thread surface roughness: external thread is 634.7 for internal thread, and the carbon steel surface shall be oxidized. 49 5.1 Products shall be inspected 100%. JB/T6296.7-92 Except for the first two threads and the screw tail, no incomplete threads are allowed. 5.2 The thread surface shall be smooth and flat, and no cracks, folds, dents and cracks are allowed. 5.3 The product surface shall be smooth and flat, and no cracks, dents, burrs, rounded edges and flash are allowed: the shape and position tolerances of the product shall comply with the drawings and standard requirements. Rust prevention, packaging, marking, storage The product shall be coated with anti-rust oil according to JB2901. The packaging boxes and other items should have signs or labels on the outside with the following contents: Manufacturer name; Product name; Product mark; ·Product quantity or net weight: Manufacturing date or production batch number, 6.3 The form and method of product packaging can be determined by the manufacturer, but under normal storage and transportation conditions, the product should be protected from damage or loss. 6.4 The product should be stored in a dry place, Additional instructions: Under normal circumstances, the anti-rust period of the product is 12 months. This standard was proposed and coordinated by the Shanghai Power Generation Equipment Complete Design Institute. This standard was drafted by Shanghai Steam Turbine Plant and Shanghai Power Generation Equipment Complete Design Institute. The main drafters of this standard are Fu Shengqing, Ren Qihua, Fang Chonghua, 50 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.