General technical requirements

 

1. Parts are descaled.

2. There should be no flaws such as scratches or scratches on the surface of the parts.

3. Remove burr flash.

 

Heat treatment requirements

1. After tempering, HRC50～55.

2. The parts are quenched by high frequency, tempered at 350～370℃, HRC40～45.

3. Carburizing depth is 0.3mm.

4. Perform high temperature aging treatment.

 

Tolerance requirements

1. The tolerance of unfilled shape should meet the requirements of GB1184-80.

2. The tolerance of unfilled length dimension is ±0.5mm.

3. The tolerance zone of the casting is symmetrical to the basic size configuration of the blank casting.

 

Part angle

1. Unfilled corner radius R5.

2. Unfilled chamfers are 2×45°.

3. Sharp corners/sharp corners/sharp edges are blunt.

 

Assembly requirements

1. All seals must be saturated with oil before assembly.

2. The assembly of rolling bearings is allowed to be hot-installed by oil heating. The temperature of the oil must not exceed 100°C.

3. After the gear is assembled, the contact spots and backlash on the tooth surface should meet the requirements of GB10095 and GB11365.

4. It is allowed to use sealing packing or sealant when assembling the hydraulic system, but it should be prevented from entering the system.

5. The parts and components (including outsourcing parts and outsourcing parts) that enter the assembly must have the certification of the inspection department before assembly.

6. The parts must be cleaned and cleaned before assembly. There must be no burrs, flashes, scales, rust, swarf, oil stains, colorants and dust.

7. Before assembly, the main matching dimensions of parts and components, especially the interference fit dimensions and related accuracy, should be reviewed.

8. During assembly, parts are not allowed to knock, bump, scratch and rust.

9. When tightening screws, bolts and nuts, it is strictly prohibited to strike or use unsuitable screwdrivers and wrenches. Screw heads, nuts, screws and bolt heads shall not be damaged after tightening.

10. Fasteners with specified tightening torque requirements must be torque wrenches and tightened according to the specified tightening torques.

11. When the same part is fastened with multiple screws (bolts), the screws (bolts) need to be crossed, symmetrical, stepwise, and evenly tightened.

12. The taper pin should be painted with the hole during assembly, and its contact rate should not be less than 60% of the mating length, and should be evenly distributed.

13. The flat keys and the two sides of the keyway on the shaft should be evenly contacted, and there should be no gaps on their mating surfaces.

14. The number of tooth surfaces simultaneously contacted by spline assembly is not less than 2/3, and the contact rate should not be less than 50% in the length and height direction of the key teeth.

15. After the sliding-fit flat keys (or splines) are assembled, the phase fittings can move freely without unevenness.

16. After bonding, excess adhesive should be removed.

17. The semicircular holes of the bearing outer ring, open bearing housing and bearing cover are not allowed to be stuck.

18. The outer ring of the bearing should be in good contact with the semicircular hole of the open bearing housing and the bearing cover. When inspected by painting, the bearing housing should be 120° symmetrical to the center line and the bearing cover should be 90° symmetrical to the center line. Even contact. When checking with a feeler gauge within the above range, a feeler gauge of 0.03mm shall not be inserted into 1/3 of the width of the outer ring.

19. After the outer ring of the bearing is assembled, the end face of the bearing cap at the positioning end should be evenly contacted.

20. After the rolling bearing is installed, it should rotate flexibly and smoothly by hand.

21. The joint surface of the upper and lower bearing pads should be tightly fit, and can not be checked with a 0.05mm feeler gauge.

22. When the bearing pad is fixed by the positioning pin, the hinge and the pin should be drilled while ensuring that the opening surface and end surface of the shoe face and the end surface of the bearing hole are flush with each other. Do not loosen after the pin has been driven in.

23. The bearing body of the spherical bearing and the bearing seat should be evenly contacted, and checked by painting method, the contact should not be less than 70%.

24. When the surface of the alloy bearing lining is yellow, it is not allowed to use, and there is no nuclear separation within the specified contact angle. The area of ​​nuclear separation outside the contact angle shall not be greater than 10% of the total area of ​​the non-contact area.

25. The reference end surface of the gear (worm gear) and the shaft shoulder (or the end surface of the positioning sleeve) should be close to each other, and cannot be checked with a 0.05mm feeler gauge. And should ensure the perpendicularity requirements of the gear reference end face and the axis.

26. The interface between the gear box and the cover should be in good contact.

27. Strictly inspect and remove the sharp angles, burrs and foreign objects remaining during parts processing before assembly. Ensure that the seal is not scratched when it is inserted.

 

Casting requirements

1. No cold barriers, cracks, shrinkage holes, penetrating defects and serious defects (such as under-casting, mechanical damage, etc.) are allowed on the surface of the casting.

2. The casting should be cleaned without burrs or flashes. The non-processing indication should be cleaned and flush with the casting surface.

3. The characters and signs on the non-machined surface of the casting shall be legible and the position and font shall comply with the drawing requirements.

4. Roughness of non-machined surface of castings, sand casting R, not more than 50μm.

5. Castings should be cleared of pouring risers, flying thorns, etc. The remaining amount of the riser on the non-processed surface should be leveled and polished to meet the surface quality requirements.

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

7. The casting has inclined parts, and its size tolerance zone should be symmetrically arranged along the inclined surface.

8. Molding sand, core sand, core bone, fleshy, sticky sand, etc. on the castings should be shoveled and leveled to clean it.

9. Correction of wrong shape and casting of bosses should be corrected to achieve a smooth transition and ensure the appearance quality.

10. The wrinkle of the non-machined surface of the casting shall be less than 2mm deep and the distance shall be greater than 100mm.

11. Non-machined surfaces of machine product castings need to be shot-blasted or roller-treated to meet the requirements of cleanliness Sa2 1/2.

12. Castings must be water-toughened.

13. The surface of the casting should be smooth, and the gate, burrs, and sticky sand should be removed.

14. Castings are not allowed to have casting defects such as cold partitions, cracks, holes, etc. that are detrimental to the use.

 

Painting requirements

1. Before painting the surface of all steel parts that need to be painted, rust, scale, grease, dust, dirt, mud, salt and dirt must be removed.

2. Before removing rust, use an organic solvent, lye, emulsifier, steam, etc. to remove grease and dirt on the surface of the steel parts.

3. The time interval between the surface to be coated by shot blasting or manual derusting and the primer is not more than 6h.

4. The surfaces where the riveting parts are in contact with each other must be coated with antirust paint with a thickness of 30-40 μm before connection. The overlapping edges should be closed with paint, putty or adhesive. Primers damaged due to processing or welding must be repainted.

 

Piping requirements

1. Before assembling, all pipes should be free of burrs, burrs and chamfers. Use compressed air or other methods to clear the debris and floating rust attached to the inner wall of the pipe.

2. Before assembly, all steel pipes (including prefabricated pipes) must be degreased, pickled, neutralized, washed and rust-proofed.

3. When assembling, tighten the pipe clamps, supports, flanges, and joints with screw connections to prevent loosening.

4. The welded parts of the prefabricated pipe shall undergo a pressure test.

5. When the piping is replaced or transferred, the pipe separation port must be sealed with adhesive tape or plastic pipe to prevent any debris from entering and tied to the label.

 

Repair welding requirements

1. Before welding, the defects must be completely removed, the groove surface should be repaired flat and smooth, and there should be no sharp corners.

2. According to the defects of the steel castings, the welding zone defects can be removed by shoveling, grinding, carbon arc gouging, gas cutting or mechanical processing.

3. The sticky sand, oil, water, rust and other dirt within 20mm around the welding area and the groove must be thoroughly cleaned.

4. During the whole welding process, the temperature of the preheating zone of the steel castings shall not be lower than 350°C.

5. When conditions permit, apply welding in a horizontal position as much as possible.

6. When repair welding, the electrode should not swing too much laterally.

7. When surfacing welding of steel castings, the overlap between the weld bead shall not be less than 1/3 of the width of the weld bead. The meat is full, no burns, cracks and obvious nodules on the welding surface. The appearance of the weld is beautiful, without defects such as meat biting, slagging, porosity, cracks, and spatter; the welding wave is uniform.

 

Forging requirements

1. The sprue and riser of the ingot should have a sufficient amount of cut-out to ensure that the forgings have no shrinkage holes and serious deflection.

2. The forging should be forged on a forging press with sufficient capacity to ensure that the inside of the forging is fully forged.

3. Forgings are not allowed to have cracks, folds and other appearance defects that affect the use of the naked eye. Local defects can be removed, but the cleaning depth should not exceed 75% of the machining allowance. Defects on the non-machined surface of the forgings should be cleaned and smooth transition.

4. Forgings are not allowed to have white spots, internal cracks and residual shrinkage holes.

 

Cutting parts requirements

1. The parts should be inspected and accepted according to the process. Only after the previous process is qualified can they be transferred to the next process.

2. The processed parts are not allowed to have burrs.

3. The parts after finishing should not be placed directly on the ground, and the necessary support and protection measures should be taken. The processed surface is not allowed to have defects such as rust moth and bumps and scratches that affect performance, life or appearance.

4. After rolling, there should be no peeling after finishing.

5. The parts after heat treatment in the final process should have no scale on the surface. Finished mating surfaces and tooth surfaces should not be annealed

6. The surface of the processed thread is not allowed to have defects such as black skin, bump, buckle and burr.