General technical requirements
1. Remove scale from parts.
2. There must be no scratches, abrasions or other defects that would damage the surface of the parts on the treated surface.
3. Remove burrs and flash edges.
Heat treatment requirements
1. After quenching and tempering treatment, HRC50～55.
2. The parts are subjected to high frequency quenching, tempering at 350~370℃, HRC40~45.
3. Carburizing depth is 0.3mm.
4. Perform high temperature aging treatment.
Tolerance requirements
1. Form tolerances not noted shall conform to the requirements of GB1184-80.
2. The allowable deviation of unnotated length dimensions is ±0.5mm.
3. The casting tolerance zone is symmetrical to the basic dimensional configuration of the blank casting.
Coin corners
1. The fillet radius R5 is not noted.
2. The chamfer without note is 2×45°.
3. Sharp corners/points/edges are dull.
Assembly requirements
1. Each joint must be soaked in oil before assembly.
2. It is allowed to use oil heating for hot assembly when assembling bearings. The oil temperature must not exceed 100°C.
3. After the gear is assembled, the contact points and clearance on the tooth surface must comply with GB10095 and GB11365 regulations.
4. It is allowed to use gasket or sealant when assembling the hydraulic system, but it must be prevented from entering the system.
5. Parts and components entering the assembly (including purchased parts and subcontracted parts) must have certificates from the inspection department before they can be assembled.
6. Parts should be cleaned and cleaned before assembly, and there should be no burrs, flashes, scale, rust, chips, oil, dyes, dust, etc.
7. Before assembly, the main mounting dimensions of parts and components, particularly the mounting dimensions with interference and the associated accuracy, should be examined.
8. During the assembly process, parts should not be bumped, bumped, scratched or rusted.
9. When tightening screws, bolts and nuts, it is strictly prohibited to hit or use inappropriate screwdrivers and wrenches. Screw grooves, nuts, screws and bolt heads must not be damaged after tightening.
10. Fasteners with specified torque requirements should be tightened with a torque wrench and tightened to the specified torque.
11. When the same part is fixed with several screws (bolts), each screw (bolt) must be crossed, symmetrical, progressive and regular.To squeeze.
12. When assembling the taper pin, contact with the hole should be checked. The contact rate should not be less than 60% of the mating length and should be evenly distributed.
13. The flat key and both sides of the keyway on the shaft should be in uniform contact, and there should be no gaps on the contact surface.
14. The number of tooth surfaces in contact with the spline assembly at the same time should not be less than 2/3, and the contact rate should not be less than 50% in the length and height directions key teeth.
15. After the spanner (or spline) is assembled, the corresponding accessories can move freely and there should be no uneven sealing.
16. After gluing, excess glue should be removed.
17. The outer ring of the bearing and the semi-circular hole of the open bearing seat and the bearing cover must not get stuck.
18. The outer ring of the bearing should be in good contact with the open bearing seat and the semicircular hole of the bearing cover. When inspected by coloring, it should be within the range of 120° symmetrical to the center axis with the bearing seat. and 90° symmetrical to the centerline with the bearing cover. Uniform contact. When checking with a feeler gauge in the above range, the 0.03mm feeler gauge should not be inserted into 1/3 of the width of the outer ring.
19. After assembly, the outer race of the bearing should be in uniform contact with the end face of the bearing cap at the locating end.
20. After the bearing is installed, it must be flexible and stable to rotate by hand.
21. The mating surfaces of the upper and lower pads must be in close contact with each other and cannot be checked with a 0.05mm feeler gauge.
22. When securing the pad with a locating pin, drill the hinge and distribute the pin while ensuring that the opening surface and end surface of the pad are flush with the opening and closing surface and the end surface of the bearing hole concerned. The pin should not loosen after being pressed.
23. The bearing body and the spherical bearing seat must be in uniform contact. Use the staining method to verify that the contact should not be less than 70%.
24. The use of alloy coating is not allowed when its surface turns yellow. No nucleation is allowed within the specified contact angle. The nucleation area outside the contact angle should not exceed 10% of the total non-surface area. contact area.
25. The datum end face of the gear (worm gear) and the shoulder of the shaft (or the end face of the locating sleeve) should fit together and check with a d gauge thickness of 0.05 mm. And the circularity requirement between the reference end face of the gear and the axle must be ensured.
26. The mating surfaces of the gearbox and the cover must be in good contact.
27. Before assembly, strictly inspect and eliminate all sharp corners, burrs and foreign bodies remaining during parts processing. Make sure the gasket is not scratched when installed.
Casting Requirements
1. Cold seals, cracks, shrinkage cavities, penetrating defects and serious incomplete defects (such as under-pouring, mechanical damage, etc.) are not allowed on the surface of castings.
2. Castings must be clean and free from burrs and burrs. Casting risers on the unmachined surface must be cleaned and flush with the surface of the castings.
3. The characters and marks on the unmachined surface of the casting part must be clearly legible, and the position and font must conform to the requirements of the drawing.
4. The roughness of the unmachined surface of the molded part, cast in sand R, must not be greater than 50 μm.
5. Castings should be free from risers, spurs, etc. The remaining amount of casting and riser on the untreated surface must be leveled and polished to meet the surface quality requirements.
6. The casting sand, core sand and core bone on the casting part should be removed.
7. For castings with inclined parts, their dimensional tolerance zones must be arranged symmetrically along the inclined plane.
8. Molding sand, core sand, core bone, flesh, sticky sand, etc. on the casting must be smoothed and cleaned.
9. Bad shapes, misaligned bosses, etc. must be corrected to achieve a smooth transition and ensure quality appearance.
10. The depth of wrinkles on the unmachined surface of casting parts should be less than 2mm, and the spacing should be greater than 100mm.
11. Unmachined surfaces of machine product castings shall be shot blasted or roller treated to meet the cleanliness requirements of Sa2 1/2 level.
12. Castings should be quenched with water.
13. The surface of the casting part should be smooth and the doors, burrs, sticky sand, etc. should be smooth. must be removed.
14. Castings should not have casting defects such as cold insulation, cracks, holes, etc. which are detrimental to use.
Painting Requirements
1. Rust, scale, grease, dust, soil, salt and dirt must be removed from the surface of all steel parts to be painted before painting.
2. Before derusting, use organic solvents, lye, emulsifier, steam, etc. to remove grease and dirt from the surface of steel parts.
3. The time interval between shot blasting or manual rust removal and application of primer should not exceed 6 hours.
4. The surfaces of the riveted parts that touch each other should be coated with anti-rust paint with a thickness of 30-40 μm before connection. Overlapping edges must be sealed with paint, putty or glue. Primer that has been damaged due to machining or welding will need to be covered.
Piping Requirements
1. All pipe ends must be removed from burrs, burrs and chamfered before assembly. Use compressed air or other methods to remove debris and floating rust attached to the inner wall of the pipe.
2. Before assembly, all steel pipes (including prefabricated pipes) must be degreased, stripped, neutralized, washed and treated against rust.
3. When assembling, tighten parts such as hose clamps, brackets, flanges and joints attached with threaded connections to prevent loosening.
4. Welded parts of prefabricated pipes must undergo pressure testing.
5. When the piping is replaced or transferred, the pipe separation port should be sealed with tape or plastic pipe to prevent any debris from entering, and a label should be affixed.
Repair Welding Requirements
1. Defects should be completely eliminated before welding, and the groove surface should be smooth and smooth, without sharp corners.
2. Depending on the defects of the steel castings, the defects in the welding area can be eliminated by shoveling, grinding, carbon arc gouging, gas cutting or mechanical processing.
3. Sand, oil, water, rust and other dirt within 20mm of the welding area and groove should be carefully cleaned.
4. During the whole welding process, the temperature in the preheating zone of the steel casting should not be lower than 350°C.
5. If conditions permit, weld in a horizontal position as much as possible.
6. When repair welding, the welding rod should not swing sideways too much.
7. When welding steel casting surfaces, the overlap between weld beads should not be less than 1/3 of the width of the weld bead. The weld meat is plump and there are no obvious burns, cracks or nodules on the weld surface. The appearance of the weld is beautiful, without defects such as flesh bite, slag addition, pores, cracks, spatter, etc. ; the welding wave is uniform.
Forging Requirements
1. The nozzle and ingot riser should be cut enough to ensure that the forging does not have shrinkage holes or significant deviation.
2. Forgings must be forged and formed on a forging press of sufficient capacity to ensure that the interior of the forgings is fully forged.
3. Forgings should not have cracks, creases and other visible appearance defects that affect use. Local defects can be eliminated, but the cleaning depth should not exceed 75% of the machining allowance. Defects on the unmachined surface of the forging should be cleaned and transitioned smoothly.
4. White spots, internal cracks and residual shrinkage cavities are not allowed in forgings.
Requirements for cutting parts
1. Parts should be inspected and accepted according to the process only after the previous process passes the inspection, they can be transferred to the next process.
2. No burrs are allowed on processed parts.
3. Finished parts should not be placed directly on the ground and necessary support and protection measures should be taken. The machined surface must be free of rust, dents, scratches and other defects affecting performance, life or appearance.
4. There should be no peeling of the surface after rolling.
5. There should be no scale on the surface of the parts after heat treatment in the final process. Finished contact surfaces and tooth surfaces must not be annealed
6. The surface of the processed wire should not have defects such as black skin, bumps, random curls and burrs.
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