Left Transmission Gear Case Parts Catalog for BOMCO Drawworks

1

Plate ZLYQG880X3A-102

Gray cast iron HT250; Precision machining of sealing surface; Surface anti-rust paint coating; Flatness ≤ 0.02 mm/m

1. Sealing surface scratches due to improper installation with foreign particles; 2. Casting fatigue cracks caused by long-term gear vibration

1. Clean the sealing surface thoroughly before installation and check for foreign particles; 2. Conduct ultrasonic flaw detection on the plate every 12 months to inspect for cracks

2

Plate ZLYQG880X.4A-10Y

Gray cast iron HT250; Reinforced rib structure; Sealing surface with anaerobic sealant groove; Compressive strength ≥ 250 MPa

1. Deformation of the plate due to uneven tightening torque during installation; 2. Corrosion of the outer surface by oilfield moisture and chemicals

1. Tighten the fixing bolts in a diagonal sequence with uniform torque (≤ 80 N·m); 2. Reapply anti-corrosion paint every 6 months and check for rust spots regularly

3

Lower Casing ZLYQG8S0X.4B-101

Ductile iron QT450-10; Integral casting; Internal oil passage precision machining; Sealing surface hardness HRC 28-32

1. Sealing surface wear due to long-term friction with the upper cover; 2. Internal oil passage blockage leading to local pressure increase and deformation

1. Install a copper gasket between the lower casing and upper cover to reduce friction; 2. Clean the internal oil passage every 6 months to avoid debris accumulation

4

Upper Cover ZLYQG880X.4B-102

Ductile iron QT450-10; Surface phosphating treatment; O-ring groove precision machining; Weight reduction design with reinforced structure

1. O-ring groove wear caused by repeated assembly/disassembly; 2. Impact damage during transportation or maintenance

1. Use a guide pin during assembly to avoid scratching the O-ring groove; 2. Use shock-absorbing packaging during transportation and avoid collision during maintenance

5

Assembly End Cover ZLYQC850-9.4B-315

Carbon steel Q235B; Stamped and formed; Sealing surface grinding treatment; Equipped with bearing installation seat

1. Bearing seat wear due to long-term rotation of the shaft; 2. Seal failure caused by deformation of the end cover

1. Check the bearing seat inner diameter wear monthly (replace when wear ≥ 0.1 mm); 2. Ensure uniform stress during installation to avoid end cover deformation

6

Assembly End Cover ZLYQE830-9.4B-322

Carbon steel Q235B; Surface galvanized + anti-corrosion paint double protection; Precision positioning hole design; Coaxiality ≤ 0.03 mm

1. Galvanized layer peeling due to frequent contact with oil and chemicals; 2. Positioning hole wear leading to shaft misalignment

1. Clean the end cover surface regularly to remove oil stains and chemicals; 2. Check the positioning hole dimensional accuracy every 8 months

7

End Cover ZLYQC850-9.AB-30A

Alloy steel 45#; Quenched and tempered treatment; High wear resistance; Suitable for high-load transmission scenarios

1. Fatigue wear of the end cover due to long-term high-load operation; 2. Oil leakage caused by sealing surface aging

1. Operate within the rated load range of the drawworks; 2. Replace the sealing gasket every 6 months to ensure sealing performance

8

End Cover ZLYQC830-9.4B-309

Alloy steel 45#; Surface nitriding treatment; Wear resistance ≥ 5000 working hours; Low friction coefficient

1. Nitriding layer peeling due to improper assembly scratch; 2. Corrosion of the end cover inner surface by gear oil additives

1. Use a soft metal tool during assembly to avoid scratching the nitriding layer; 2. Select gear oil compatible with the nitriding layer material

9

End Cover ZLYQC830-9.4A-342

Carbon steel Q235B; Simple structure; Cost-effective; Suitable for medium-load transmission systems

1. Deformation of the end cover due to temperature changes in the gearbox; 2. Fastener hole wear caused by repeated disassembly

1. Avoid rapid temperature changes in the gearbox (preheat before startup in low temperature); 2. Use thread inserts when the fastener hole wear exceeds 0.2 mm

10

End Cover ZLYQC830-9AB-311

Ductile iron QT400-18; Good impact resistance; Sealing surface with rubber gasket groove; Suitable for harsh working environments

1. Impact damage from external debris in the drilling site; 2. Rubber gasket groove wear leading to sealing failure

1. Install a protective cover outside the end cover to prevent debris impact; 2. Check the rubber gasket groove wear every 5 months

1

Input Shaft ZLYQG830-9.4A-001

Alloy steel 42CrMo; Quenched and tempered treatment; Surface grinding; Hardness HRC 35-40; Tensile strength ≥ 980 MPa

1. Shaft surface wear due to long-term rotation with the bearing; 2. Fatigue fracture of the shaft shoulder caused by alternating loads

1. Ensure sufficient lubrication of the bearing to reduce friction; 2. Conduct magnetic particle inspection of the shaft shoulder every 8 months to check for fatigue cracks

2

Counter Shaft Assembly ZLYQC850-9.AA-002

Shaft body: 42CrMo alloy steel; Gear: 20CrMnTi alloy steel (carburized); Assembly coaxiality ≤ 0.02 mm; Dynamic balance grade G6.3

1. Gear tooth wear caused by meshing with other gears; 2. Loosening of assembly components due to long-term vibration

1. Check gear tooth wear monthly (replace when tooth thickness wear ≥ 10%); 2. Tighten the assembly fasteners every 500 operating hours

3

Output Shaft ZLYQC830-9.4A-003

Alloy steel 35CrMo; Nitriding treatment; Surface hardness HRC 55-60; Wear resistance ≥ 8000 working hours; Shaft end thread precision 6H

1. Nitriding layer wear due to high-load transmission; 2. Thread damage during assembly of the output component

1. Avoid overloading the drawworks (load ≤ 110% of rated load); 2. Use a torque wrench during assembly to avoid thread over-tightening

4

Pin Shaft 30X80 (GB/T120.1)

Carbon steel 45#; Quenched and tempered treatment; Surface polishing; Shear strength ≥ 600 MPa; Dimensional tolerance IT7

1. Shear deformation due to uneven force during transmission; 2. Corrosion caused by gear oil leakage and moisture intrusion

1. Check the pin shaft for bending deformation monthly; 2. Apply anti-rust lubricant to the pin shaft during assembly

1

O-ring Seal 28X2.68 (25X2.65ZGEXX52.X82)

Nitrile rubber (NBR); Shore hardness 70±5; Oil-resistant; Temperature range: -20℃ to 120℃; Compliance with GB3452.1-82

1. Aging and hardening due to long-term contact with high-temperature gear oil; 2. Scratching caused by burrs on the sealing groove

1. Replace the O-ring every 6 months; 2. Remove burrs from the sealing groove before installation and check for sharp edges

2

O-ring Seal 20X2.68 (20X2.65/GB3452.1-82)

Nitrile rubber (NBR); High elasticity; Good sealing performance under low pressure; Suitable for casing joint sealing

1. Extrusion deformation due to excessive installation pressure; 2. Swelling caused by incompatible oil additives

1. Control the installation compression amount within 20-30% of the O-ring diameter; 2. Use gear oil that complies with BOMCO specifications

3

O-ring Seal 136X3.38 (136X3.55ZGB3A52.1-82)

Fluororubber (FKM); High-temperature resistant up to 180℃; Chemical resistant; Suitable for high-load gearbox sealing

1. Thermal aging in high-temperature gearbox environments; 2. Wear caused by radial movement of the shaft

1. Monitor the gearbox temperature (≤ 160℃); 2. Check the shaft radial runout monthly (≤ 0.05 mm)

4

O-ring Seal 280X3.3 (250X5.3ZGB3A52.1-82)

Fluororubber (FKM); Large diameter; High sealing pressure resistance (≤ 5 MPa); Compliance with GB3452.1-82

1. Uneven compression leading to local leakage; 2. Damage caused by improper installation tools

1. Ensure uniform compression of the O-ring during installation; 2. Use special O-ring installation tools to avoid stretching or tearing

5

O-ring Seal 423X7 (425X7ZGB3452.1-82)

Ethylene propylene rubber (EPDM); Weather-resistant; Suitable for external sealing of the gearbox; Temperature range: -40℃ to 150℃

1. Aging caused by long-term exposure to sunlight and rain; 2. Abrasion by external dust and debris

1. Install a protective cover to shield from sunlight and rain; 2. Clean the sealing surface regularly to remove dust and debris

6

O-ring Seal 430X7 (A50X7ZGB3A52.1-82)

Ethylene propylene rubber (EPDM); Good water resistance; Suitable for wet oilfield environments; High tear strength

1. Swelling caused by moisture intrusion; 2. Tearing due to excessive stretching during installation

1. Keep the gearbox installation environment dry; 2. Avoid stretching the O-ring by more than 10% during installation

7

O-ring Seal 224X3.3 (224X5.3XGB3452.1-82)

Nitrile rubber (NBR); Oil-resistant and wear-resistant; Suitable for end cover sealing; Compliance with GB3452.1-82

1. Wear caused by repeated opening and closing of the end cover; 2. Hardening due to low-temperature operation

1. Replace the O-ring after every 3 times of end cover disassembly; 2. Preheat the gearbox to ≥ -10℃ before startup in low temperature

8

O-ring Seal 236X3.3 (236X5.3ZGB3452.1-82)

Nitrile rubber (NBR); Good elasticity and recovery; Suitable for dynamic sealing scenarios; Service life ≥ 3000 working hours

1. Fatigue wear due to dynamic movement of the shaft; 2. Damage caused by foreign particles entering the sealing gap

1. Install a dust ring to prevent foreign particles from entering; 2. Check the O-ring for fatigue cracks every 4 months

1

Bolt M12X40 (M12XX0/GB/5783)

Carbon steel 8.8 grade; Surface galvanized; Thread precision 6H; Tensile strength ≥ 800 MPa; Compliance with GB/T 5783

1. Thread wear caused by repeated disassembly; 2. Loosening due to gearbox vibration

1. Use a matching socket wrench during disassembly to avoid thread damage; 2. Install spring washers to enhance anti-loosening performance

2

Bolt M30X200 (M30X200/GB/T901)

Alloy steel 10.9 grade; Surface phosphating treatment; High strength; Suitable for fixing heavy components; Compliance with GB/T 901

1. Fatigue fracture of the bolt rod due to long-term heavy load; 2. Corrosion of the thread caused by oil and moisture

1. Operate within the rated load range to reduce bolt stress; 2. Apply anti-corrosion thread sealant during assembly

3

Nut M30 (M30/GB/T6170, M30/GB/T6172.1)

Carbon steel 8.8 grade; Surface galvanized; Hexagonal structure; Thread type metric coarse thread; Compliance with GB/T 6170, GB/T 6172.1

1. Thread wear caused by repeated matching with bolts; 2. Deformation of the nut hexagon due to improper tightening tools

1. Replace the nut when thread wear exceeds 0.1 mm; 2. Use a torque wrench with the correct size to avoid hexagon deformation

4

Bolt M20X60 (M20X60/GB/5783, M20X60/GB/8782)

Carbon steel 8.8 grade; Surface galvanized; Different thread lengths for different installation scenarios; Compliance with GB/T 5783, GB/T 8782

1. Bolt rod bending due to uneven stress during installation; 2. Galvanized layer peeling caused by collision

1. Ensure the installation surface is flat to avoid uneven stress; 2. Use shock-absorbing packaging during transportation

5

Spring Washer 20 (20/GB93-87, 20/GB92X7)

Carbon steel 65Mn; Elastic deformation range 5-10%; Surface oxide layer; Compliance with GB/T 93, GB/T 92

1. Loss of elasticity due to long-term compression; 2. Fracture caused by excessive compression

1. Replace the spring washer every time the bolt is disassembled; 2. Control the tightening torque to avoid excessive compression

6

Bolt M16X50 (M16X50/GB/5783)

Carbon steel 8.8 grade; Surface galvanized; Suitable for fixing light components; Thread length 50 mm; Compliance with GB/T 5783

1. Thread jamming due to mud and debris intrusion; 2. Corrosion in humid oilfield environments

1. Clean the thread with a brush before assembly; 2. Apply anti-rust lubricant to the thread

7

Spring Washer 16 (16/GB92X7)

Carbon steel 65Mn; Small size; Good anti-loosening performance for small bolts; Compliance with GB/T 92

1. Wear of the washer surface due to friction; 2. Deformation caused by improper installation

1. Check the washer surface for wear before installation; 2. Ensure the washer is correctly placed between the bolt and the component

8

Nut M36 (B136/GB/T6170, M26/GBX6172.1)

Alloy steel 10.9 grade; Surface phosphating treatment; High strength; Suitable for large bolts; Compliance with GB/T 6170, GB/T 6172.1

1. Thread corrosion caused by oil and chemical intrusion; 2. Loosening due to severe vibration

1. Clean the nut thread regularly to remove oil and chemicals; 2. Use double nuts for anti-loosening in high-vibration positions