Hydraulic Cylinder Export from China: FOB vs CIF vs DDP Explained

Incoterms and Hydraulic Cylinder Procurement

When you purchase hydraulic cylinders from a Chinese manufacturer like Wuxi Hengshui Machinery, the price you pay and the risks you assume depend on the Incoterm (International Commercial Term) agreed in your purchase contract. The three most commonly used Incoterms in China hydraulic cylinder export are FOB, CIF, and DDP.

Choosing the right Incoterm affects your total landed cost, your responsibility for customs clearance and import duties, and what happens if goods are damaged in transit.

FOB – Free On Board

FOB Shanghai / FOB Wuxi means the seller (Wuxi Hengshui) is responsible for the cylinders until they are loaded onto the ship at the named port. From that point, all shipping costs, freight insurance, customs clearance in your country, and import duties are your responsibility.

Who pays what under FOB:

Seller pays: Factory price + domestic trucking to port + export customs clearance + loading onto vessel
Buyer pays: Ocean freight + marine insurance + destination port charges + import duties + inland delivery to your warehouse

When FOB works best: You have a freight forwarder in China or a logistics arrangement that gets you competitive ocean freight rates. You import frequently and are comfortable managing international shipping. FOB typically gives you the most control and often the lowest total cost for experienced importers.

CIF – Cost, Insurance and Freight

CIF [destination port] means the seller pays for the cost of goods, ocean freight to the destination port, and minimum marine insurance. Risk transfers to the buyer once goods are on board the vessel in China — but the seller handles the freight booking.

Who pays what under CIF:

Seller pays: Factory price + domestic trucking + export clearance + ocean freight + marine insurance
Buyer pays: Destination port charges + import customs clearance + import duties + inland delivery

When CIF works best: You want a single price that includes freight to your port, but you can handle import customs and inland delivery yourself. CIF is common for buyers in Russia, Australia, and South Africa who have established import agents.

DDP – Delivered Duty Paid

DDP [buyer’s location] is the most comprehensive Incoterm. The seller handles everything — freight, insurance, export clearance, import customs, import duties, and delivery to the buyer’s door. The buyer simply receives the goods at their warehouse.

Who pays what under DDP:

Seller pays: Everything — factory price + all freight + insurance + export clearance + import duties + inland delivery to buyer
Buyer pays: Nothing additional (all costs are included in the DDP price)

When DDP works best: First-time importers, buyers who want a simple all-in price with no surprises, or purchases of smaller quantities where managing international logistics is not cost-effective. Note: The DDP price will be higher than FOB because the seller includes all costs and a logistics margin.

Practical Comparison for Hydraulic Cylinder Buyers

Factor	FOB	CIF	DDP
Quoted price	Lowest	Medium	Highest
Buyer logistics work	Most	Some	None
Risk transfer point	On board vessel	On board vessel	Your door
Import duty responsibility	Buyer	Buyer	Seller
Best for	Experienced importers	Mid-level importers	First-time / small orders

Export Packing and Rust Prevention

Regardless of Incoterm, all hydraulic cylinders from Wuxi Hengshui Machinery are prepared for export shipment with:

Rod end protection: plastic rod caps and stretch-wrap on chrome rods
Port protection: plastic port plugs to prevent contamination
Rust prevention: VCI (Volatile Corrosion Inhibitor) film wrap on all metal surfaces
Export crating: wooden crates or palletised cartons suitable for sea freight and long-distance transport

Request a Quote with Your Preferred Incoterm

Wuxi Hengshui Machinery quotes cylinder prices on FOB, CIF, and DDP basis. When submitting an inquiry, please specify your destination port or city and your preferred Incoterm. We will provide a complete landed-cost breakdown.

How to Specify a Custom Hydraulic Cylinder: 8 Key Parameters

Why Clear Specification Is Critical

When ordering a custom hydraulic cylinder, the quality and accuracy of your specification directly determines the accuracy of the quotation, the correctness of the manufactured part, and ultimately the performance of the equipment. A vague enquiry (“I need a 100mm cylinder, 500mm stroke”) will result in multiple back-and-forth clarifications and possible errors. A complete specification results in a fast, accurate quote and a correctly manufactured cylinder.

This guide covers the 8 parameters that Wuxi Hengshui Machinery engineers need to produce an accurate quotation and manufacturing drawing for a custom hydraulic cylinder.

Parameter 1: Bore Diameter (ID)

The bore is the inside diameter of the cylinder tube. This is the primary parameter because it determines the push force (extend force) at a given pressure.

Formula: Force (kN) = Pressure (bar) × π/4 × Bore² (mm²) × 0.001

Example: A 100mm bore cylinder at 200 bar produces approximately 157 kN of push force.

Common bore sizes at Wuxi Hengshui: 32, 40, 50, 63, 80, 100, 125, 160, 200, 250, 320, 400, 500mm and any non-standard dimension.

Parameter 2: Rod Diameter

The rod diameter affects the pull (retract) force and the rod’s buckling resistance under compressive load. As a rule of thumb:

Light duty: rod = 0.5 × bore
Standard duty: rod = 0.6–0.7 × bore
Heavy duty / long stroke: rod = 0.8–1.0 × bore

For long-stroke cylinders or those with large side loads, a larger rod or a guided cylinder design may be required.

Parameter 3: Stroke Length

Stroke is the total travel distance from fully retracted to fully extended. Specify the required stroke clearly. Long strokes require special attention to rod buckling calculations and bearing length.

Also specify: retracted length (closed length / minimum overall length) if there is a space constraint.

Parameter 4: Working Pressure

Specify the maximum continuous working pressure in bar (or PSI). Also indicate the proof/test pressure if different from 1.5× working pressure (our default test level).

Pressure ranges at Wuxi Hengshui: up to 500 bar for standard designs; higher pressures by custom arrangement.

Parameter 5: Mounting Style

How the cylinder attaches to the machine structure. Common options include:

Front flange (FF): bolted flange on the front head
Rear flange (RF): bolted flange on the cap end
Foot/side lug: bolts through the body to machine frame
Clevis pin: pivoting pin mount at cap end
Trunnion: pivoting pin at mid-body or cap end
Rod eye/clevis: pivoting attachment at rod end

Providing a mounting drawing or reference to an existing cylinder is the most reliable way to specify this.

Parameter 6: Port Size and Position

Specify the thread type (BSP, NPT, metric), size, and port position (port A at cap end, port B at rod end is standard; alternative positions available). Cushion valves (deceleration at end-of-stroke) should be specified if required.

Parameter 7: Seal Material

Based on operating temperature and hydraulic fluid:

NBR: General purpose, mineral oil, up to 100°C
FKM (Viton): High temperature, phosphate ester fluid, up to 200°C
Polyurethane: High pressure, high-wear dynamic sealing

Wuxi Hengshui Machinery uses Merkel (Germany) and Parker (USA) seal kits as standard.

Parameter 8: Surface Finish and Coating

Specify rod surface finish (hard chrome plating is standard, with minimum 25μm chrome thickness), cylinder tube bore honing specification (Ra 0.2–0.4μm is our standard), and any external coating requirements (paint colour/type, nickel plating, or special coatings for corrosive environments).

How to Submit Your Specification

The fastest way to get an accurate quotation is to:

Send a dimensioned drawing (PDF, DWG, DXF, or STEP) to sales@wx-hxy.com
Or complete the online inquiry form with the 8 parameters above
Or send specifications via WhatsApp to +86 133 8224 8877

Wuxi Hengshui Machinery responds to all technical enquiries within 24 hours, with a preliminary quotation typically within 48 hours.

Metallurgical Industry Hydraulic Cylinders: Key Applications in Steel Plants

Why Metallurgical Applications Demand Custom Hydraulic Cylinders

Steel and metallurgical plants operate some of the most demanding hydraulic cylinder applications in industry: high loads, high pressures, elevated ambient temperatures, scale and water contamination, and continuous duty cycles. Off-the-shelf cylinders rarely meet these requirements — which is why virtually all heavy metallurgical hydraulic circuits are equipped with custom-engineered, non-standard hydraulic cylinders.

Wuxi Hengshui Machinery supplies hydraulic cylinders to metallurgical customers across multiple countries, with equipment deployed in continuous casting machines, rolling mills, electric arc furnaces, and steel plant auxiliary systems.

Main Application Points in a Steel Plant

1. Continuous Casting Machine (CCM) Cylinders

Continuous casting machines use hydraulic cylinders for mould oscillation, strand guide roll adjustment, withdrawal and straightening, and dummy bar insertion. These cylinders must handle:

Extreme ambient heat (radiant heat from molten steel)
Water and scale contamination
Precise positional control (often ±0.1mm accuracy)
High-cycle fatigue resistance

Typical bore range: 50–250mm. Chrome plating on rods is standard; special wiper seals with integrated scrapers are often required.

2. Rolling Mill Screwdown & Roll Adjustment Cylinders

Hot and cold rolling mills use hydraulic screwdown cylinders to control roll gap — the space between work rolls that determines final strip thickness. These are typically large-bore, short-stroke cylinders operating at very high pressures (200–350 bar) with servo-hydraulic control. Bore sizes commonly range from 200mm to 500mm+.

3. AOD Converter & Ladle Tilting Cylinders

Argon oxygen decarburisation (AOD) converters and steel ladles are tilted using heavy hydraulic cylinders operating in extremely hot environments. FKM (Viton) seals are mandatory for these applications. Cylinder bore: 150–400mm; stroke: 1000–3000mm.

4. Electric Arc Furnace (EAF) Tilting & Electrode Cylinders

EAF tapping cylinders tilt the furnace body to pour molten steel into the ladle. Electrode lifting cylinders raise and lower graphite electrodes during the melt. Both applications require:

High side-load resistance
Heat-resistant seals (FKM)
Corrosion-resistant chrome plating on rods
Large bore (150–500mm), long stroke (up to 3000mm)

5. Hydraulic Press & Forging Press Cylinders

Forging presses in steel plants use very large bore cylinders at extreme pressures. Main press rams may be 800–1200mm bore at 315–400 bar. Auxiliary cylinders (ejectors, die cushions, transfer systems) are smaller but still non-standard in most cases.

Material & Seal Specifications for Metallurgical Cylinders

Wuxi Hengshui Machinery uses:

Cylinder tubes: Huai Steel (淮钢) and Tianjin Seamless Pipe — supplied with full material certificates, tested for hardness and dimensional accuracy before production
Piston rods: Hard chrome plated (minimum 25μm Chrome thickness) or nickel-chrome for corrosive environments
Seals: Parker or Merkel FKM for high-temperature zones; NBR for general applications
Surface protection: Rod boot / accordion guards recommended for environments with heavy scale or water spray

How to Order

To obtain a quotation for metallurgical hydraulic cylinders, please supply:

Cylinder drawing (PDF, DWG, or DXF) or dimensional specification sheet
Working pressure (bar)
Ambient temperature range
Hydraulic fluid type
Required quantity and delivery schedule

Contact Wuxi Hengshui Machinery at sales@wx-hxy.com or WhatsApp +86 133 8224 8877. We respond with a preliminary quotation within 24 hours. Send inquiry →

Hydraulic Cylinder Seal Materials: NBR vs FKM vs Polyurethane – How to Choose

Why Seal Material Selection Matters

In a hydraulic cylinder, the seals are the most maintenance-sensitive component. Seal failure causes external leakage, internal bypass, and ultimately cylinder failure. The correct seal material must withstand the system’s operating pressure, temperature range, and the specific hydraulic fluid being used.

Wuxi Hengshui Machinery sources all seals from German Merkel and American Parker — two of the world’s leading manufacturers of hydraulic sealing systems. We offer three primary seal materials for custom hydraulic cylinders.

NBR (Nitrile Butadiene Rubber)

Best for: General-purpose industrial hydraulics with mineral oil

NBR is the most widely used hydraulic seal material. It offers excellent resistance to petroleum-based hydraulic oils, mineral oils, and many solvent vapours.

Temperature range: −30°C to +100°C (−22°F to +212°F)
Pressure resistance: up to 350 bar with appropriate backup rings
Compatible fluids: Mineral oil (ISO VG 32–68), hydraulic oil (HM, HV type)
Not recommended for: phosphate ester fluids, ketones, strong acids

NBR is the standard seal material in most Wuxi Hengshui cylinders for metallurgical, press, crane, and construction machinery applications where petroleum-based hydraulic oil is used.

FKM / Viton (Fluoroelastomer)

Best for: High-temperature environments, fire-resistant fluids

FKM (commercially known as Viton) provides superior heat resistance and chemical compatibility compared to NBR. It is the seal of choice for electric furnace cylinders, foundry equipment, and applications near high-temperature zones.

Temperature range: −20°C to +200°C (−4°F to +392°F)
Pressure resistance: up to 400 bar
Compatible fluids: Phosphate ester (HFD), synthetic esters, high-temperature mineral oils
Not recommended for: ketones, amines, steam at high temperatures

FKM seals are specified for Wuxi Hengshui electric furnace tilting cylinders, die casting machine cylinders, and any application where ambient temperatures exceed 100°C.

Polyurethane (PU)

Best for: High-pressure, high-speed, high-wear dynamic sealing

Polyurethane seals are harder than rubber-based seals and provide outstanding wear resistance and extrusion resistance under high pressures. They are used primarily for rod seals and piston seals in high-dynamic-load applications.

Temperature range: −40°C to +90°C (−40°F to +194°F)
Pressure resistance: up to 500 bar (ideal for high-pressure cylinders)
Key advantages: Excellent abrasion resistance, low friction, good extrusion resistance
Used for: Rod seals, wiper seals, piston seals in press and forging applications

Summary: Which Seal to Choose?

Property	NBR	FKM	Polyurethane
Max Temp	100°C	200°C	90°C
Max Pressure	350 bar	400 bar	500 bar
Wear Resistance	Good	Good	Excellent
Mineral Oil	✓ Excellent	✓ Good	✓ Good
Cost	Low	High	Medium
Typical Use	General industrial	High-temp / furnace	High-pressure press

When ordering a custom cylinder from Wuxi Hengshui Machinery, specify your hydraulic fluid type, maximum operating temperature, and working pressure. Our engineers will recommend the appropriate seal package from our Merkel and Parker seal inventory. Contact our sales team at sales@wx-hxy.com.

What Is a Non-Standard Hydraulic Cylinder? Definition, Types & When to Order Custom

What Does “Non-Standard” Mean in Hydraulic Cylinders?

A non-standard hydraulic cylinder (also called a custom or bespoke cylinder) is one manufactured to specific dimensions, pressure ratings, mounting configurations, or seal specifications that fall outside the dimensional standards of off-the-shelf catalogue products.

Standard hydraulic cylinders follow widely adopted bore/stroke series — such as ISO 6020 or ISO 6022 for mill-type cylinders, or NFPA T3.6.7 for tie-rod designs. Any cylinder that deviates from these standard series in bore diameter, stroke, port size, mounting style, seal material, or surface finish is classified as non-standard.

Why Choose a Non-Standard Hydraulic Cylinder?

Most industrial machinery — particularly metallurgical equipment, custom press lines, material handling systems, and OEM production machines — has space constraints, load profiles, and duty cycles that no off-the-shelf cylinder can optimally serve. Non-standard manufacturing allows engineers to:

Match exact envelope dimensions (bore, stroke, retracted and extended length)
Achieve the precise working pressure for the load without over-engineering
Select seal materials appropriate for the operating temperature and fluid type
Specify mounting flanges, clevis eyes, or trunnions to interface directly with existing structures
Apply surface treatments (hard chrome, electroless nickel, PTFE coating) to resist corrosion or wear

Key Parameters That Define a Custom Hydraulic Cylinder

When ordering a non-standard hydraulic cylinder, you need to specify the following parameters:

Bore diameter (ID) — The inside diameter of the cylinder tube, which determines the thrust force at a given pressure.
Rod diameter — The diameter of the piston rod; larger rods handle higher column loads and buckling resistance.
Stroke length — The total travel distance of the piston from fully retracted to fully extended.
Working pressure — The maximum continuous operating pressure (bar or PSI).
Mounting style — Front flange, rear flange, side lugs, clevis, trunnion, or foot mounting.
Port size and position — The thread size and location of hydraulic inlet/outlet ports.
Seal material — NBR, FKM (Viton), polyurethane, or PTFE depending on temperature and fluid.
Surface finish — Hard chrome plating on rod, honing specification on bore (typically Ra 0.2–0.4μm).

How Wuxi Hengshui Manufactures Non-Standard Cylinders

Wuxi Hengshui Machinery Co., Ltd. specialises entirely in non-standard custom hydraulic cylinder manufacturing. Our production process begins with your drawings (DWG, DXF, PDF, STEP) or a physical sample, and proceeds through:

Engineering review and drawing confirmation
Raw material procurement (Huai Steel tube, Tianjin Seamless pipe)
CNC rough and finish machining
Precision honing to Ra 0.2μm
Component cleaning and assembly with Merkel or Parker seals
100% hydrostatic pressure test at 1.5× rated working pressure
Surface coating, packing, and export shipment

MOQ is 1 piece. Lead time is typically 15–25 working days. Contact our sales team at sales@wx-hxy.com with your drawings or specifications for a free quotation within 24 hours.

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