Remove the scale from the parts.

There should be no scratches, wear and other defects on the machined surface of the parts.

Remove burrs and flash.

2. Heat treatment requirements:

After conditioning, HRC 50 ~ 55.

High frequency quenching of parts, tempering at 350 ~ 370℃, HRC 40 ~ 45.

The carburizing depth is 0.3 mm.

Carrying out high-temperature aging treatment.

3. Tolerance requirements:

The unmarked shape tolerance shall meet the requirements of GB 1 184-80.

The allowable deviation of unspecified length and size is 0.5mm.

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

4. Parts edges and corners:

Unregistered fillet radius R5.

All unmarked chamfers are 2× 45.

Acute angles are blunt.

5. Assembly requirements:

All seals must be saturated with oil before assembly.

When assembling rolling bearings, oil heating is allowed, and the oil temperature shall not exceed 100℃.

After the gearbox is assembled, no-load test shall be carried out according to the design and technology. There should be no impact and noise during the test, and the temperature rise and leakage should not exceed the relevant standards.

After the gear is assembled, the tooth surface contact point and backlash shall comply with GB 10095 and GB 1 1365.

When assembling the hydraulic system, sealing packing or sealant is allowed, but it should be prevented from entering the system.

Parts (including purchased parts and outsourced parts) entering assembly must be certified by the inspection department before assembly.

Parts must be cleaned before assembly, free of burrs, flash, scale, rust, debris, oil stains, colorants and dust.

Before assembly, check the main fit dimensions of parts, especially the interference fit dimensions and related accuracy.

Parts are not allowed to be knocked, collided, scratched and rusted during assembly.

When fastening screws, bolts and nuts, it is forbidden to knock or use inappropriate screwdrivers and wrenches. Thread grooves, nuts, screws and bolt heads shall not be damaged after fastening.

Fasteners with specified tightening torque requirements must be tightened with a torque wrench.

When the same part is fastened with multiple screws (bolts), the screws (bolts) should be tightened crosswise, symmetrically, step by step and evenly.

Taper pins should be coated with holes when assembling, and the contact rate should not be less than 60% of the mating length, and should be evenly distributed.

Ping Jian should be in uniform contact with both sides of the keyway on the shaft, and there should be no gap between the mating surfaces.

The number of tooth surfaces contacting at the same time in spline assembly shall not be less than 2/3, and the contact rate in the length and height direction of key teeth shall not be less than 50%.

After assembling Ping Jian (or spline) with sliding fit, the parts can move freely without uneven tightness.

After bonding, the excess adhesive should be removed.

The outer ring of the bearing and the semi-circular hole of the open bearing seat and bearing cover are not allowed to be stuck.

The bearing outer ring should be in good contact with the semi-circular holes of the open bearing seat and bearing cover. During coloring inspection, it should be in uniform contact with the bearing seat within the range of 120 symmetry to the center line and with the bearing cover within the range of 90 symmetry to the center line. 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 outer ring width.

After the bearing outer ring is assembled, it should be in uniform contact with the end face of the bearing cover at the positioning end.

After the rolling bearing is installed, it should be flexible and stable to rotate by hand.

The joint surfaces of upper and lower bearing shells should be closely attached, and cannot be checked with a 0.05mm feeler gauge.

When fixing the bearing bush with the locating pin, the drilling hinge should cooperate with the pin under the condition that the opening and closing surface of the bearing hole is flush with the end surface package. After driving, the pin must not be loose.

The bearing body and bearing seat of spherical bearing should be in uniform contact, and the contact should not be less than 70% painted.

When the surface of alloy bearing liner is yellow, it is not allowed to be used, and there is no nucleation phenomenon within the specified contact angle. The nucleation area outside the contact angle should not be greater than 10% of the total non-contact area.

The reference end face of the gear (worm wheel) should be stuck on the shaft shoulder (or the end face of the positioning sleeve), and it cannot be checked with a 0.05mm feeler gauge. And should ensure the verticality of gear reference end face and axis.

The joint surface of gear box and cover should be in good contact.

Strictly check and remove sharp corners, burrs and foreign objects left in the processing of parts before assembly. Ensure that the seal will not be scratched when loading.

6. Casting requirements:

Cold insulation, cracks, shrinkage cavities, penetration defects and serious incomplete defects (such as under-casting, mechanical damage, etc.). ) are not allowed to appear on the casting surface.

Castings should be cleaned without burrs and flash, and risers on non-machining instructions should be cleaned and flush with the surface of castings.

Casting characters and signs on the unprocessed surface of castings should be clearly identifiable, and the position and font should meet the requirements of drawings.

The roughness (sand casting R) of the unprocessed surface of the casting shall not exceed 50μ m. ..

Castings should be free of gates, risers and flying thorns. Runners and risers left on the unprocessed surface should be leveled and polished to meet the surface quality requirements.

Molding sand, core sand and core bone on castings should be removed.

The casting has an inclined part, and its size tolerance zone should be symmetrically arranged along the inclined plane.

Molding sand, core sand, core bone, meat sand, sticky sand, etc. on castings should be shoveled, smoothed and cleaned.

Dislocation, boss casting deviation, etc. Correction should be made to achieve a smooth transition and ensure the appearance quality.

The depth of wrinkles on the unprocessed surface of castings should be less than 2mm, and the spacing should be greater than100 mm..

The unmachined surface of mechanical product castings needs shot peening or roller treatment to meet the requirements of cleanliness Sa2 1/2.

Castings must be water toughened.

The casting surface should be smooth, and the gate, burr and sand adhesion should be removed.

Casting defects such as cold insulation, cracks and holes that are harmful to use are not allowed.

7. Paint requirements:

Before painting, rust, scale, grease, dust, soil, salt and dirt on all steel surfaces that need painting must be removed.

Before rust removal, use organic solvent, alkali liquor, emulsifier and steam to remove grease and dirt on the steel surface.

The time interval between shot blasting or manual derusting and priming should not exceed 6h.

Before connection, the surfaces of riveted parts in contact with each other must be coated with 30 ~ 40μ m thick antirust paint. Lap edges shall be sealed with paint, putty or adhesive. Primer damaged by machining or welding shall be repainted.

8. Pipeline requirements:

All pipes shall be deburred and chamfered before assembly. Use compressed air or other methods to remove impurities and floating rust attached to the inner wall of the pipeline.

Before assembly, all steel pipes (including prefabricated pipes) shall be degreased, pickled, neutralized, cleaned and rustproof.

When assembling, the parts of pipe clamp, bracket, flange and joint fixed by thread should be tightened to prevent looseness.

The welded parts of prefabricated pipes shall be subjected to pressure test.

When the pipeline is replaced or transported, the pipeline separation port must be sealed with adhesive tape or plastic pipe to prevent any sundries from entering, and the label must be fastened.

9. Requirements for repair welding parts:

Before repair welding, the defects must be completely removed, and the groove surface should be smooth and flat without sharp corners.

According to the defects of steel castings, the defects in the repair welding area can be removed by shoveling, grinding, carbon arc gouging, gas cutting or machining.

Sand, oil, water, rust and other dirt within 20mm around the repair welding area and groove must be thoroughly cleaned up.

During the whole repair welding process, the temperature in the preheating zone of steel castings shall not be lower than 350℃.

If conditions permit, weld in a horizontal position as far as possible.

When repairing welding, covered electrode should not make a big lateral swing.

When stacking welding is carried out on the surface of steel castings, the overlap between weld beads should not be less than 1/3 of the weld bead width.

10. Forging requirements:

The nozzle and riser of each ingot should have enough cutting capacity to ensure that the forging has no shrinkage cavity and serious deviation.

Forgings should be forged on a forging press with sufficient capacity to ensure full forging inside the forgings.

Forgings are not allowed to have visible cracks, folds and other appearance defects that affect the use. Local defects can be removed, but the depth of removal shall not exceed 75% of the machining allowance, and the defects on the non-machined surface of forgings shall be cleaned and smoothly transferred.

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

1 1. Cutting requirements:

Parts should be inspected and accepted according to the working procedure, and can only be transferred to the next working procedure after passing the inspection in the previous working procedure.

The machined parts are not allowed to have burrs.

Finished parts shall not be directly placed on the ground, and necessary support and protection measures shall be taken. No rust, bump, scratch or other defects affecting performance, service life or appearance are allowed on the machined surface.

The rolled surface shall be free from peeling after rolling.

There should be no scale on the surface of parts after heat treatment in the last process. After finishing, the mating surface and tooth surface should not be annealed, blue or discolored.

The machined thread surface is not allowed to have defects such as black skin, bump, disorderly buckle and burr.

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