4140 Piston Rod
Product description:

A 4140 piston rod is a high-strength mechanical component used in hydraulic cylinders, pneumatic systems, and industrial machinery where superior toughness, fatigue resistance, and durability are required. Manufactured from AISI 4140 alloy steel, this piston rod is designed to withstand high stress, heavy loads, and continuous reciprocating motion under harsh operating conditions. With its exceptional mechanical properties and outstanding wear resistance, the 4140 piston rod is an ideal choice for heavy-duty hydraulic applications such as construction equipment, mining machinery, and industrial presses.

The piston rod is a connecting component that supports the piston in performing work. It is mostly used in oil cylinders and air cylinders as motion execution components and is a frequently moving and highly technical motion component. Taking the hydraulic cylinder as an example, it is composed of the cylinder barrel, piston rod (oil Cylinder rod), piston, and end cover. The quality of its processing directly affects the lifespan and reliability of the entire product. The processing requirements for the piston rod are high. Its surface roughness should be within the range of Ra0.4 to 0.8 μm, and strict requirements are imposed on coaxiality and wear resistance.

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Material Composition and Properties

AISI 4140 steel is a chromium-molybdenum (Cr-Mo) alloy steel containing approximately 0.40% carbon, 1.0% chromium, and 0.2% molybdenum. This unique alloy composition provides a perfect balance between tensile strength, impact toughness, and hardenability, making it far superior to medium carbon steels such as 1045.

After quenching and tempering, 4140 steel achieves high hardness (up to HRC 28–32 before surface treatment), excellent fatigue strength, and superior resistance to mechanical shock. To further improve surface performance, 4140 piston rods are usually hard chrome plated, nitrided, or induction hardened, providing exceptional resistance to corrosion, pitting, and surface wear.

Manufacturing Process

The manufacturing of a 4140 piston rod involves advanced precision processes to ensure consistent quality, dimensional accuracy, and long-lasting performance:

• Material Selection: Premium-grade 4140 alloy steel bars are selected for uniform chemical composition and microstructure.
• Heat Treatment: Quenching and tempering optimize hardness, strength, and impact resistance.
• Precision Machining: CNC turning, threading, and grooving ensure high accuracy and consistent geometry.
• Centerless Grinding: Achieves excellent roundness, straightness, and dimensional tolerance.
• Surface Treatment: Hard chrome plating or nitriding provides a tough, corrosion-resistant finish.
• Polishing: Mirror finishing reduces friction and improves sealing performance.
• Inspection: Each rod is inspected for hardness, straightness, coating thickness, and surface roughness.

Key Features and Advantages

• High Strength and Toughness: Withstands heavy loads and high working pressures.
• Excellent Fatigue Resistance: Ideal for continuous reciprocating motion under dynamic stress.
• Superior Surface Hardness: Chrome plating and nitriding protect against wear and corrosion.
• Dimensional Accuracy: Precision machining and grinding ensure perfect alignment and smooth movement.
• Long Service Life: Enhanced durability reduces maintenance and replacement costs.
• Thermal and Mechanical Stability: Performs reliably under extreme temperatures and mechanical stress.

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Applications:

The hydraulic cylinder is an energy conversion device that converts hydraulic energy into mechanical energy. It is the core actuating component in the hydraulic system. The hydraulic cylinder uses hydraulic oil to drive the piston to move, converting hydraulic energy into linear reciprocating motion. When the hydraulic oil enters the cylinder barrel, it pushes the piston rod to extend or retract, completing the predetermined action. The direction and speed of its movement are regulated by the hydraulic control system. The hydraulic cylinder consists of a cylinder barrel, cylinder cover, piston and piston rod, sealing device, and buffering device. According to its structure, it can be classified as piston type, plunger type, multi-stage telescopic sleeve type, and gear-rack type. Hydraulic cylinders are widely used in machine tools, construction machinery, vehicles, and other fields, featuring a simple structure and smooth movement.

4140 piston rods are widely used in demanding hydraulic and mechanical systems that require superior strength, impact resistance, and corrosion protection, including:

• Hydraulic cylinders for construction machinery, mining, and cranes
• Industrial automation equipment and robotic actuators
• Oil and gas drilling machinery
• Agricultural and forestry hydraulic systems
• Marine and offshore hydraulic systems
• Heavy-duty industrial presses and forging machines
• Its combination of strength, precision, and corrosion resistance makes the 4140 piston rod ideal for long-term operation under high load and pressure environments.

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Why us?

We focus on the research, development, production and sales of seamless steel pipes, special-shaped steel pipes and hydraulic cylinders. We have a complete production chain and an advanced equipment system, including piercing machines, cold drawing machines, hot rolling machines, high-precision flaw detection and testing equipment. The company has passed multiple authoritative certifications such as ISO9001, API, SGS, CCS, DNV, ABS, CE, RoHS, etc., ensuring that each product complies with international standards. We are committed to providing customers with high-quality, customizable solutions to meet diverse application needs.

Relying on our own built processing base and modern workshops, combined with multiple branches and storage centers across the country, we have achieved sufficient inventory and efficient logistics coordination, significantly shortening the delivery cycle and ensuring the rapid delivery of orders.

We have established a complete service and support system. After the order is signed, the professional after-sales team can provide timely and safe on-site guidance and technical support to ensure that customers are at ease throughout the process from procurement to use.

FAQ:

1. Do you support customized design and production?

Sure. We have a professional engineering team that can conduct customized design and production with special sizes, control systems or OEM according to your requirements.

2. How fast can you deliver?

In stock sizes, it takes 3-5 days. For customized sizes, it takes 30-35 days.

3. What payment methods do you support?

We support TT payment. Generally, 30% to 50% of the payment is made in advance, and the remaining amount is paid before shipment.

4. Can you provide material certification (MTC)?

Yes, we will provide MTC to you after production is completed to ensure that the material quality meets the standards.

5. What is the minimum order quantity?

Generally, we accept trial orders. The minimum order quantity is 1-3 tons, which can be determined according to different products.