Secondary technical experts hexagonal threaded parts insurance hole processing high temperature alloy nut tap cutting internal thread process bottom hole diameter and deviation common thread plug gauge M thread plug gauge measurement internal thread process bottom hole with smooth plug gauge common thread plug gauge M thread Plug gauges, high-strength steel, M-threads, taps, taps, shoulders, undercuts, and chamfers. Basic dimensions and deviations of the M-threaded bottom hole. Technical conditions. Preparation, signing, approval and issuance of parts and materials consumption process quota thread parts safety hole size processing nut use equipment cutting nuts should have the following basic equipment: multi-axis automatic lathe hex lathe ordinary lathe horizontal milling machine vertical milling machine vertical drilling machine bench drill The design of the nut of the fitter table requires the technical requirements of the nut. 5.1 Dimensions and tolerances The dimensions and tolerances of the nut are in accordance with the design drawings and the corresponding standard requirements. The general dimensional tolerances are according to yeah 5800. For nuts made with hexagonal bars, the size of the wrenches Tolerance, hexagonal circumscribed circle diameter tolerance, and hexagonal plane roughness rating
5.2 Allow the surface shape of the nut to have the following tolerances: for hex nuts, round nuts and nuts for interference fit, their support end recess X is not more than 0.1 mm. The convexity X1 of their support end faces should not exceed Specified value: For a nut with a nominal diameter of 8 mm or less, X1 is not more than 0.05 mm. For a nominal diameter greater than 5.3, the tolerances of the surface positions of the nut are as follows: 5.3.1 Coaxiality 519 specifies: the outer surface axis of the hexagon is opposite to The concentricity of the thread axis, or the coaxiality of the outer circle axis of diameter D with respect to the thread axis, allows for a deviation X2. The tolerance of the concentricity is equal to the dimensional tolerance of the hexagon or the dimensional tolerance of the diameter D.
519 stipulates that the tolerance of the nut support end face to the thread axis is X3. For hex nuts and round nuts, the tolerance of the perpendicularity at the maximum boundary dimension D, and the perpendicularity of the maximum boundary dimension L of the pallet nut The tolerances shall comply with the requirements of Table 1.
Nut type D or L All nuts except the round nut Round nut Note: For tanned nuts, the vertical tolerance is 0.01D or L. For stamped hex nuts, the vertical tolerance is 0.02D. Q/3B78 It is stated that the perpendicularity of the nut support end face to the thread center line is as follows: 5.4 The thread should be smooth, without burrs, dents and defective threads, allowing: at the top of the tooth shape while maintaining the inner diameter of the thread With rounded corners; on one end of the nut, the thread diameter increases by less than 0.5 mm in the range of twice the pitch; allows the chamfering of the thread of 30 in the range of the thread depth; allows bending on the first stitch Sharp edge.
5.5 The tensile strength of the tensile strength nut shall be in accordance with the design drawings and the corresponding standards.
The tensile strength of the nut shall not be lower than the value specified in Table 2. When the load reaches the value specified in Table 2, the thread on the nut shall not be cracked, sheared or peeled off.
Table 2 Thread failure tensile force N (kgf) processing process 6.1 Typical process route 38CrA, 1Cr17Ni2 hex nut processing route circle (six square) bar material one grinding bar material both ends chamfering an automatic locomotive processing a chamfering one milling six way to go Burr one wash one heat treatment one tapping thread one car end face one drill lock wire hole one deburring one wash one final inspection one surface treatment 1Cr18Ni9Ti hexagonal groove nut processing route circle (six square) bar material one polished bar end one automatic Locomotive machining a chamfering one milling six square one deburring one washing one heat treatment one milling flower groove one deburring one clearing inner hole burr one tapping thread one deburring one washing one final inspection one surface treatment 1Cr11NiW2MoV hex nut processing route circle ( Liufang) bar material one material heat treatment one grinding bar material both ends head one hex car processing one chamfering one milling six side one deburring one diamond lock wire hole one deburring one tapping thread one deburring one washing-strength test A final inspection of a surface treatment GH2696 hex nut processing route round bar material one solution treatment a hexagonal car processing a chamfering one milling six square one deburring a diamond lock Wire hole deburring, tapping thread, deburring, washing, intermediate inspection, aging treatment, washing, final inspection, surface treatment, processing of TC6 hex nut, round bar material, one car ring groove, one heat treatment, one hexagonal car plus one Deburring a diamond lock wire hole deburring a tapping thread a chamfering a milling thread a deburring a washing one aging treatment a final inspection 6.2 process preparation standards 150 process procedures preparation, signing, approval and issuance requirements. The process of the nut is as follows: 6.2.1 Material grade of the wool process diagram of the wool process, and the technical conditions of the material are selected according to the design drawing or metallurgical documents.
Classification material grade material standard bar material parts wool diameter and loss of wool material determination and material consumption quota calculation 6.2.2 hexagonal car processing diagram nut semi-finished trial production and small batch production, arranged in hexagonal lathe processing; Large time is arranged in automatic lathe processing.
When preparing the process chart, pay attention to the technical requirements of the nut. The bottom hole of the common internal thread process is selected according to the diameter and deviation of the bottom hole of the internal thread process of HB 3874. The internal thread of M is selected according to the basic size and deviation of the bottom hole of the M internal thread cutting process of HB6222.
38753886 Measured internal thread process bottom hole is measured with a smooth plug gauge using a gauge. The chamfering at both ends of the female threaded hole is calculated according to the HB5829 thread chamfering type and size selection.
6.2.3 Automatic lathe processing (the first processing method) fixture / 1 艮 true 6.2.4 锪 threaded hole chamfering process 锪 threaded hole chamfering process pattern (0) size and form according to HB 5829 ordinary thread finishing, shoulder Distance, undercut and chamfer selection.
6.2.5 Milling hexagonal process (1) Milling hexagonal process is only prepared for the production of round bar material, and its surface roughness and technical requirements are implemented in accordance with the relevant technical documents. When milling, care should be taken to ensure that the symmetry of the hexagonal surface to the threaded hole meets the specified requirements; the milling hexagonal process fixture is selected by the indexing indexing fixture and the double milling cutter. The milling process can also be carried out after tapping; after milling the hexagon, the deburring process should be arranged to sharpen the sharp edges of the parts to maintain the minimum size of the hexagonal diagonal.
6.2.6 Heat treatment process The sketch of the heat treatment of the nut at the hard spot inspection is shown in (2), organized by the heat treatment workshop to ensure the hardness and strength requirements of the heat treatment of the nut gauge. The location of the heat treatment process is primarily determined by the effect of material hardness on the life of the tool, the size of the part, the surface roughness, and the impact on machine life.
Generally, the hardness of the material is lower than HRC40 and arranged in the heat treatment of wool or semi-finished products (before the thread is not processed). The hardness of the material is higher than HRC40 and the heat treatment is arranged after the finished product (after processing the thread).
For the nut processing of high-hardness materials, considering the life of the thread cutter, the wool solution treatment is arranged to soften the material and machine the thread. After the thread is processed, the finished product is aged (argon protection). The heat treatment is required to be protected by pure argon gas, and no oxidation occurs during the heat treatment, and the product size and precision are not damaged.
6.2.7 Milling groove process (3) Nut flower groove is processed according to design drawings and technical requirements. The gap between the six-groove nut groove and the groove is 60°, and the groove between the four-groove nut groove and the groove should be 90; pay attention to the symmetry of the groove and the position of the hexagonal surface during processing, and use the six aspects of clamping as the positioning reference; It is necessary to arrange for burrs before tapping.
Since the burr in the direction of the inverted inner hole is difficult to remove when the groove is milled, the drill is used to re-pass the hole, and the burr stuck to the groove side is removed from the inner side of the hole.
6.2.8 Thread processing steps (4) The thread type is specified according to the design drawings. The thread size is selected according to the standard, and the roughness is according to the technical documents.
The thread is the main component of the nut and the tolerance is small. If the thread is arranged before the heat treatment, the scale generated by the heat treatment is not easy to remove, and the diameter of the thread and the size of the thread are affected, and the surface roughness is also lowered. Therefore, the threading is performed as much as possible after the heat treatment. The methods for machining threads are tapping, milling and threading. Below the M12, the tap is used in the vertical thread cutter according to HB36593680 and special tools.
When machining the thread, care should be taken to ensure the perpendicularity of the nut end face to the thread axis. The thread bottom hole should be adjusted coaxially with the thread diameter to prevent the thread from being eccentric; the thread diameter should be checked with the standard HB38883891 thread plug gauge or special thread plug gauge. The outer diameter of the thread is guaranteed by the forming tool; check the nut support end face to the thread center line. Verticality, using the internal thread vertical gauge (5). When measuring, screw the thread gauge into contact with the end face of the nut support, and then insert the plug into the gap between the end face of the nut and the end face of the thread gauge to measure the verticality.
The degree requirement is to arrange the end face of the car nut with the thread axis as the reference below 0.05 to ensure the technical requirements. The chamfer of this end face should be made larger in the previous process, which is convenient to reduce the burr at the thread entrance and exit of the end face of the car.
6.2.10 Drilling and locking wire hole process 0-9 Threaded parts safety hole requirements and regulations processing, process drawings Because the hex nut is drilled on the inclined surface, the drill bit slides a large amount, so it is allowed to use HB0-9 in processing. Process hole processing. It is also possible to drill holes in the drilling tool. The drilling tool should be designed with the amount of drill bit down to ensure the minimum wall thickness of the locking wire hole. It can be measured according to the minimum wall thickness dimension in S99.T.7 to ensure the strength of the hole wall.
6.3 Inspection procedure (8) 8 6.3.1 Inspection of the visual inspection nut shall be carried out at room temperature, and the appearance of the nut shall be visually inspected. For nuts with a diameter less than 2.5mm, it is allowed to observe with 58 times magnifying glass; the surface roughness of the nut meets the requirements of the design drawings, and the surface roughness of the thread is determined according to the technical documents. Appearance: There should be no cracks, burrs, dents, scars and other mechanical damage on the surface of the nut. The sharp edges of the nut surface should be blunt. Surface defects allowed in the technical conditions of the material are allowed to exist; dents and nicks left by the tool (tool) are allowed, but should not exceed half of the dimensional tolerances examined.
6.3.2 Dimensional inspection The nut size and shape tolerance shall be as required by the design drawings. Use extreme gauges, prototypes, general gauges and other tools for inspection. The thread is checked by a thread plug gauge.
6.4 Other inspection procedures Crack inspection of nuts by magnetic flaw detection, fluorescence and other inspection methods. Flaw detection defects are specified in the design drawings. According to the design drawings, the mechanical properties of the nut are checked by strength test and other methods.
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