Contour processing of parts

1. The unmarked shape tolerance should comply with the requirements of GB1184-80.
2. The allowable deviation for unmarked length dimensions is ± 0.5mm.
3. Undeclared fillet radius R5.
4. Undeclared chamfers are all C2.
5. Sharp corners are rounded off.
6. Blunt off sharp edges and remove burrs and burrs.
Surface treatment of parts
1. There should be no scratches, scratches, or other defects that damage the surface of the parts on the processed surface.
2. The surface of the processed thread shall not have defects such as black skin, bumps, loose threads, and burrs. All steel surfaces that require painting must be cleaned of rust, scale, grease, dust, soil, salt, and dirt before painting.
3. Before rust removal, use organic solvents, lye, emulsifiers, steam, etc. to remove grease and dirt from the surface of steel parts.
4. The time interval between the surface to be coated and the primer coating after shot blasting or manual rust removal shall not exceed 6 hours.
5. The surfaces of riveted parts in contact with each other must be coated with a thickness of 30-40 before connection μ M Anti rust paint. The overlapping edges should be sealed with paint, putty, or adhesive. Primer damaged due to processing or welding needs to be repainted.
Heat treatment of parts 1. After quenching and tempering treatment, HRC50-55. 2. Medium carbon steel: 45 or 40Cr parts undergo high-frequency quenching, tempered at 350~370 ℃, and HRC40~45. 3. The carburization depth is 0.3mm. 4. Perform high-temperature aging treatment.
Technical requirements after precision machining: 1. The parts after precision machining should not be placed directly on the ground, and necessary support and protection measures should be taken. 2. The machined surface shall not have defects such as rust or scratches that affect performance, lifespan, or appearance. 3. The surface of rolling precision machining shall not have peeling phenomenon after rolling. 4. After the final process heat treatment, the surface of the parts should not have oxide skin. The mating surface and tooth surface that have undergone precision machining should not be annealed
Sealing treatment of parts: 1. Each sealing component must be soaked in oil before assembly. 2. Before assembly, strictly inspect and remove any sharp corners, burrs, and foreign objects left during part processing. Ensure that the seal is not scratched during installation. 3. Excess adhesive should be removed after bonding.
Technical requirements for gears: 1. After gear assembly, the contact spots and backlash on the tooth surface should comply with the provisions of GB10095 and GB11365. 2. The reference end face of the gear (worm gear) should fit closely with the shaft shoulder (or locating sleeve end face), and cannot be checked with a 0.05mm feeler gauge. And the perpendicularity requirement between the gear reference end face and the axis should be ensured. 3. The joint surface between the gearbox and the cover should have good contact.

Technical requirements for bearings
1. The assembly of rolling bearings allows the use of oil heating for hot installation, and the temperature of the oil should not exceed 100 ℃. 2. The outer ring of the bearing and the half round holes of the open bearing seat and bearing cover must not be stuck. 3. The outer ring of the bearing should have good contact with the semi-circular holes of the open bearing seat and bearing cover. When checking with color coating, the contact with the bearing seat should be evenly distributed within the range of 120 ° symmetrical to the centerline and 90 ° symmetrical to the centerline of the bearing cover. When using a feeler gauge to check within the above range, a 0.03mm feeler gauge should not be inserted into 1/3 of the outer ring width. 4. After assembly, the outer ring of the bearing should have even contact with the end face of the positioning end bearing cover. 5. After installation, the rolling bearing should rotate flexibly and smoothly by hand. 6. The joint surface of the upper and lower bearing shells should be tightly fitted and cannot be checked with a 0.05mm feeler gauge. 7. When using positioning pins to fix the bearing shells, drilling and matching pins should be carried out while ensuring that the surface and end face of the bearing shell are flush with the opening and closing surfaces of the relevant bearing holes. The pin must not loosen after being driven in. 8. The bearing body and bearing seat of spherical bearings should be in uniform contact, and the contact should not be less than 70% when inspected by the color coating method. 9. When the surface of the alloy bearing liner is yellow, it is not allowed to use it. There should be no detachment within the specified contact angle, and the detachment area outside the contact angle should not exceed 10% of the total area of the non-contact area.

Technical requirements for screws, bolts, and nuts
1. When tightening screws, bolts, and nuts, it is strictly prohibited to strike or use inappropriate screwdrivers and wrenches. After tightening, the screw slots, nuts, screws, and bolt heads must not be damaged. 

2. Fasteners with specified tightening torque requirements must use a torque wrench and be tightened according to the specified tightening torque. 

3. When multiple screws (bolts) are used to tighten the same part, each screw (bolt) needs to be tightened crosswise, symmetrically, gradually, and evenly. 4. The flat key and the two sides of the keyway on the shaft should be in uniform contact, and there should be no gap between their mating surfaces.

Technical requirements for repair welding

1. Before repairing welding, the defects must be thoroughly removed, and the groove surface should be trimmed flat and smooth without sharp corners. 

2. According to the defect situation of steel castings, the defects in the repair welding area can be removed by methods such as shovel excavation, grinding, carbon arc air gouging, gas cutting, or mechanical processing. 

3. The repair welding area and dirt such as sand, oil, water, rust, etc. within 20mm around the groove must be thoroughly cleaned. 

4. During the entire process of repair welding, the temperature in the preheating zone of the steel casting shall not be lower than 350 ° C. 

5. Wherever possible, welding should be carried out in a horizontal position. 

6. When repairing welding, the welding rod should not undergo excessive lateral swing. 

7. When stacking welding on the surface of steel castings, the overlap between weld beads shall not be less than 1/3 of the weld bead width. Technical requirements for castings


1. The tolerance zone of castings is symmetrical to the basic size configuration of rough castings. 

2. Cold shuts, cracks, shrinkage cavities, penetrating defects, and serious defects such as under casting and mechanical damage are not allowed on the surface of castings. 

3. Castings should be cleaned thoroughly without burrs or burrs, and the sprue and riser on non machined surfaces should be cleaned flush with the surface of the casting. 

4. The casting characters and markings on the non machined surface of the casting should be clear and distinguishable, and the position and font should meet the requirements of the drawing. 

5. Roughness of non machined surface of castings, sand casting R, not greater than 50 μ M. 

6. Castings should be cleaned of sprues, burrs, etc. The residual amount of the sprue on the non machined surface should be leveled and polished to meet the surface quality requirements. 

7. The molding sand, core sand, and core bone on the casting should be removed thoroughly. 

8. Castings with inclined parts and their dimensional tolerance zones should be symmetrically arranged along the inclined plane. 

9. The molding sand, core sand, core bone, excess flesh, sticky sand, etc. on the casting should be scraped flat and cleaned. 

10. Corrections should be made to the misalignment and protruding casting deviation to achieve a smooth transition and ensure the appearance quality. 

11. The wrinkles on the non machined surface of the casting should have a depth of less than 2mm and a spacing of more than 100mm. 

12. The non machined surfaces of machine product castings require shot peening or roller treatment to meet the cleanliness requirement of Sa2 1/2 level. 

13. Castings must undergo water toughening treatment. 

14. The surface of the casting should be flat, and the gates, burrs, and sand sticking should be removed thoroughly.

15. Castings are not allowed to have casting defects such as cold shuts, cracks, and holes that are detrimental to use.



Technical requirements for forgings
1. The water inlet and riser of each steel ingot should have sufficient cutting amount to ensure that the forging is free from shrinkage and severe bending. 2. Forgings should be formed by forging on a forging press with sufficient capacity to ensure sufficient internal penetration of the forging. 3. Forgings shall not have visible cracks, folds, or other appearance defects that affect their use. Local defects can be removed, but the cleaning depth should not exceed 75% of the machining allowance. Defects on non machined surfaces of forgings should be cleaned and smoothly transitioned. 4. Forgings are not allowed to have white spots, internal cracks, and residual shrinkage cavities.


Assembly technical requirements

1. When assembling the hydraulic system, it is allowed to use sealing fillers or sealants, but they should be prevented from entering the system. 2. The parts and components (including purchased parts and outsourced parts) that enter the assembly must have a certificate of conformity from the inspection department before they can be assembled. 3. The parts must be cleaned and cleaned before assembly, without burrs, burrs, oxide skin, rust, chips, oil stains, colorants, and dust. 4. Before assembly, the main fitting dimensions of parts and components, especially the interference fit dimensions and relevant precision shall be rechecked.
5. During the assembly process, parts are not allowed to be bumped, scratched, or corroded. 6. The taper pin shall be color checked with the hole during assembly, and its contact rate shall not be less than 60% of the fitting length, and shall be evenly distributed. 7. The number of teeth in contact with the spline assembly at the same time shall not be less than 2/3, and the contact rate shall not be less than 50% in the direction of the length and height of the key teeth. 8. After the assembly of sliding flat keys (or splines), the corresponding accessories can move freely without any uneven tightness. 9. Before assembly, all pipes should be free of burrs, burrs, and chamfers at the pipe ends. Use compressed air or other methods to remove debris and rust adhering to the inner wall of the pipe. 10. Before assembly, all steel pipes (including pre formed pipelines) must undergo degreasing, acid washing, neutralization, water washing, and rust prevention treatment. 11. During assembly, the fixed parts of pipe clamps, supports, flanges, and joints connected with threads should be tightened to prevent loosening.