Tongs Auxiliary Equipment Classification

1

Tongs Counter Weight

Tongs Counter Weight, 111.53.230.00

Gray Cast Iron HT250 (Surface Anti-Corrosive Painted)

1. Impact deformation caused by collision with hard objects during material handling or transportation; 2. Corrosion of the anti-corrosive paint layer in humid or corrosive environments, leading to base metal rust; 3. Fatigue cracking at the connection interface caused by long-term alternating load; 4. Weight loss caused by surface abrasion in dusty working conditions.

1. Avoid collision between the counterweight and hard objects; install a rubber buffer pad at the easily collided position if necessary; 2. Inspect the anti-corrosive paint layer monthly, and touch up with anti-corrosive paint immediately if peeling or rust is found; 3. Conduct non-destructive testing (NDT) for cracks at the connection interface every 6 months, and replace the counterweight if cracks are detected; 4. Clean the counterweight surface regularly to remove dust and debris, and avoid long-term accumulation of abrasive particles.

2

Copper sleeve φ35/φ25

Copper sleeve φ35/φ25, 111.53.230.01

Tin Bronze CuSn10P1 (Oil-Impregnated Self-Lubricating)

1. Abrasive wear caused by friction with the matching pin shaft due to insufficient lubrication; 2. Seizure caused by foreign debris entering the fitting gap; 3. Corrosion caused by moisture intrusion and chemical substances in the working environment; 4. Deformation caused by excessive interference during installation or overloading.

1. Take advantage of the oil-impregnated self-lubricating property, and supplement lithium-based grease every 3 months in high-load scenarios; 2. Clean the fitting surface of the copper sleeve and pin shaft before installation to remove debris; 3. Avoid using the copper sleeve in environments with strong acids, alkalis, or corrosive gases; 4. Control the installation interference within 0.02-0.04mm, and use a press-fitting tool for installation to avoid deformation; 5. Replace the copper sleeve if the inner diameter wear exceeds 0.5mm or if seizure occurs.

3

Mini sheave

Mini sheave, 111.53.230.02

Ductile Iron QT450-10 (Groove Surface Hard Chrome Plated)

1. Groove surface wear caused by long-term friction with the wire line; 2. Wear of the inner hole caused by friction with the pin shaft; 3. Corrosion of the non-chrome-plated surface in humid environments; 4. Crack caused by impact load during sudden start-stop of tongs operation.

1. Check the groove surface wear regularly; replace the mini sheave if the wear depth exceeds 1mm or the groove surface becomes irregular; 2. Apply lubricating oil between the inner hole and the pin shaft every 2 weeks to reduce friction; 3. Clean the sheave surface regularly, and apply anti-corrosive paint to the non-chrome-plated parts; 4. Avoid sudden start-stop of the tongs to reduce impact load on the sheave; 5. Conduct visual inspection for cracks monthly, and use magnetic particle testing (MPT) for key parts every year.

1

Washer

Washer, 111.53.230.03

Spring Steel 65Mn (Heat Treated, Zinc Plated)

1. Elastic fatigue caused by repeated compression and release under high vibration; 2. Corrosion of the zinc plating layer leading to loss of elastic performance; 3. Deformation caused by uneven stress distribution; 4. Wear at the contact surface with bolts/nuts due to long-term vibration.

1. Do not stack multiple washers; ensure one washer is used per bolt to guarantee effective load distribution; 2. Replace washers in batches every 12 months or after 500 high-load operation cycles, whichever comes first; 3. Ensure the installation surface is flat and free of debris to avoid uneven stress; 4. Store unused washers in a dry and ventilated environment to prevent zinc layer corrosion.

2

Pin φ25×90

Pin φ25×90, 111.53.230.04

Alloy Steel 35CrMo (Quenched and Tempered)

1. Fatigue cracking caused by long-term alternating load and vibration; 2. Abrasive wear caused by friction with the copper sleeve; 3. Corrosion caused by moisture intrusion into the fitting gap; 4. Shear failure caused by overloading or improper installation.

1. Conduct pre-installation inspection to ensure the pin is free of surface defects; 2. Apply anti-rust lubricating grease to the pin surface before installation to reduce friction with the copper sleeve; 3. Check the pin for bending and surface wear every month, and replace if the wear depth exceeds 0.3mm; 4. Strictly follow the rated load of the pin, and avoid overloading the tongs; 5. Use the matching cotter pin to secure the pin to prevent axial movement.

3

Cotter pin 5×36

Cotter pin 5×36, GB91-86(5×36)

Carbon Steel Q235 (Galvanized)

1. Fatigue fracture at the bending part caused by long-term vibration; 2. Galvanization layer damage leading to rust; 3. Shear failure caused by exceeding the rated shear force due to improper bending angle; 4. Wear at the insertion end due to repeated disassembly.

1. Ensure the bending angle is 45-60 degrees during installation to avoid excessive stress concentration; 2. Replace the cotter pin immediately if the galvanization layer is damaged or rust is found; 3. Do not reuse cotter pins that have been bent more than twice; use new cotter pins after each disassembly; 4. Use special pliers for bending to avoid damaging the cotter pin body.

4

Bolt M20×55

Bolt M20×55, GB5780-86(M20×55-8.8)

Alloy Steel 40Cr (Heat Treated, Zinc Plated)

1. Fatigue loosening caused by high-frequency vibration during tongs operation; 2. Thread wear caused by cross-threading during installation; 3. Hydrogen embrittlement caused by improper electroplating process; 4. Corrosion in humid or corrosive working environments.

1. Use thread locking adhesive or lock washers to prevent loosening in high-vibration scenarios; 2. Ensure the bolt and nut threads are clean and free of debris before installation; use a torque wrench to control the tightening torque within 350-400 N·m; 3. Select bolts with qualified electroplating processes, and avoid using them in environments with hydrogen sulfide; 4. Inspect the bolt surface for corrosion and thread damage every month, and replace immediately if any defects are found.

5

Slotted nut M20

Slotted nut M20, GB6178-86(M20-8)

Alloy Steel 40Cr (Heat Treated, Black Oxide Coated)

1. Thread stripping caused by over-tightening or mismatched bolt specifications; 2. Corrosion of the oxide coating leading to thread seizure; 3. Wear of the slot caused by repeated insertion and removal of cotter pins; 4. Deformation caused by impact load.

1. Strictly match with M20 bolts of the same material grade (8.8 grade); avoid mixing with non-standard bolts; 2. Apply anti-seize lubricant to the threads in humid environments to prevent seizure; 3. Use special tools to insert and remove cotter pins to avoid damaging the nut slot; 4. Check the nut slot for deformation and thread integrity after each heavy-load operation cycle, and replace if necessary.

6

Flat washer 20

Flat washer 20, GB95-87(20)

Carbon Steel Q235 (Zinc Plated)

1. Deformation caused by uneven stress; 2. Corrosion of the zinc plating layer leading to rust; 3. Wear at the contact surface with the nut and installation base due to vibration; 4. Cracking caused by over-tightening.

1. Ensure the installation base is flat and free of burrs; clean the contact surface before installation; 2. Replace the flat washer if obvious deformation, rust, or wear is found; 3. Do not over-tighten the bolt to avoid washer cracking; follow the specified torque range; 4. Store unused washers in a dry environment to prevent corrosion.

7

Cotter pin 4×36

Cotter pin 4×36, GB91-86(4×36)

Carbon Steel Q235 (Galvanized)

1. Fatigue fracture caused by long-term vibration; 2. Rusting caused by galvanization layer damage; 3. Shear failure due to improper installation; 4. Wear at the insertion end due to repeated use.

1. Match the cotter pin specification with the slotted nut M20 slot size; ensure a tight fit; 2. Replace the cotter pin after each disassembly; do not reuse; 3. Inspect the cotter pin for rust and damage before installation, and use new ones if any defects are found; 4. Bend the cotter pin properly to ensure it fully locks the slotted nut, avoiding loose connection.

1

Guide pole

Guide pole, 111.53.232.00

Seamless Steel Pipe 20# (Surface Hard Chrome Plated)

1. Abrasive wear caused by friction with the matching sliding parts; 2. Corrosion of the chrome plating layer in humid or corrosive environments, leading to base metal rust; 3. Bending deformation caused by impact or improper storage; 4. Scratches on the surface caused by contact with sharp objects.

1. Apply lubricating oil to the surface of the guide pole every 2 weeks to reduce friction with sliding parts; 2. Inspect the chrome plating layer monthly; repair scratches and peeling with chrome plating repair agent if necessary; 3. Avoid impact on the guide pole during transportation and installation; store it in a straight state to prevent bending; 4. Clean the guide pole surface regularly to remove dust and debris, avoiding abrasive wear; 5. Replace the guide pole if bending deformation exceeds 0.5mm/m.

2

Clip 120×φ60×φ6

Clip 120×φ60×φ6, 111.53.220.01

Stainless Steel 316

1. Fatigue cracking caused by repeated clamping and releasing under dynamic load; 2. Corrosion caused by exposure to seawater (for port applications) or chemical agents; 3. Wear at the clamping surface caused by friction with the wire line; 4. Deformation caused by over-tightening during installation.

1. Avoid installing the clip at the bending position of the wire line to reduce repeated stress; 2. For port or chemical environments, conduct weekly corrosion inspections and apply anti-corrosive spray; 3. Ensure the clamping surface is clean and free of burrs before installation to reduce wear on the wire line; 4. Use a torque wrench to control the clamping force within the specified range (25-30 N·m) to avoid deformation; 5. Replace the clip immediately if cracks or severe corrosion are found.

3

Wire line L=50m

Wire line L=50m, GB/T8918-1996(6×19-φ12.5-17)

High-Strength Carbon Steel (Galvanized, Core-Filled Grease)

1. Wear of wire strands caused by friction with the mini sheave and clip; 2. Rusting caused by galvanization layer damage and moisture intrusion; 3. Fatigue breakage of wire strands caused by repeated bending; 4. Kinking and deformation caused by improper operation; 5. Strength reduction caused by oil loss of core-filled grease.

1. Check the mini sheave groove regularly to ensure it matches the wire line diameter (groove diameter 13-13.5mm); replace worn grooves in time; 2. Apply anti-rust lubricating grease to the wire line every month to supplement the core-filled grease and repair the galvanization layer; 3. Avoid bending the wire line at a small radius (minimum bending radius ≥ 125mm) and kinking during operation; 4. Replace the wire line if the number of broken wires in any 100mm length exceeds 5, or if obvious kinking and deformation are found; 5. Store the wire line in a coiled state in a dry and ventilated environment, avoiding moisture and extrusion.