Steel round rod

for machiningfor general purposeshigh-strength

Product overview
The 4140 chrome-plated rod, normalized to HRC 15–22, is a piston rod manufactured from 4140 alloy steel and finished with a hard chrome layer. It is engineered for hydraulic and pneumatic cylinder use where a balance of toughness, wear resistance, machinability and precise surface finish is required. The combination of normalization and chrome plating provides controlled hardness, improved fatigue performance and corrosion protection for industrial applications.

Key specifications (from product summary)

• Brand: EAST AI
• Material: 4140 alloy steel
• Length: Standard up to 8,000 mm; custom lengths up to 15 m available
• ID/OD tolerance options: f7 / f8 / g6 (and others on request)
• Straightness: ≤ 0.2 mm/m
• Application: Hydraulic cylinders for mobile equipment, industrial machinery and heavy-duty systems
• Packing: Anti-rust oil on rod surface; each rod packed in paper roll and wooden case; customized packaging available
• Surface roughness: Ra ≤ 0.2 µm

Advantages

• Superior mechanical properties: Higher tensile strength and toughness versus standard carbon steels, suitable for heavy-duty loading.
• Enhanced surface finish: Hard chrome plating delivers low friction, excellent wear resistance and consistent surface quality.
• Controlled hardness: Normalizing produces HRC 15–22 for an optimum balance between machinability and durability.
• Corrosion protection: Chrome layer provides resistance to rust and environmental degradation.
• Dimensional accuracy: Precision centerless grinding ensures tight tolerances and smooth cylinder operation.
• Versatility: Suited to hydraulic/pneumatic cylinders, lifting machinery, construction and agricultural equipment.

Production process

• Raw material selection: High-grade 4140 alloy steel is procured.
• Peeling and straightening: Surface defects removed and rods straightened to specification.
• Normalizing heat treatment: Rods are heated and air-cooled to refine grain structure and achieve uniform hardness (HRC 15–22).
• Centerless grinding: Diameter tolerances and surface smoothness are achieved.
• Hard chrome plating: Uniform chrome layer applied for wear and corrosion resistance.
• Polishing and finishing: Final polishing to meet Ra ≤ 0.2 µm.
• Inspection and testing: Mechanical, dimensional and surface checks are performed prior to dispatch.

Applications

• Hydraulic cylinders: Piston rods for construction machinery, excavators and forklifts.
• Pneumatic cylinders: Low-friction rods for pneumatic systems.
• Industrial machinery: Presses, lifting equipment and automated systems.
• Agricultural equipment: Hydraulic arms and implements for tractors and harvesters.
• Marine applications: Corrosion-resistant rods for offshore and marine machinery.
• Mining equipment: Heavy-duty rods for drilling rigs and loaders.

Product Details
Material: 4140 alloy steel
Condition: Normalized
Hardness: HRC 15–22
Surface coating: Hard chrome plated (chrome layer thickness 20–30 µm)
Surface roughness: Ra ≤ 0.2 µm
Tolerances: f7 / h8 (ID/OD options such as f7 / f8 / g6 available)
Straightness: ≤ 0.2 mm/m
Diameter range: Ø 6 mm – Ø 350 mm
Length: Standard up to 8,000 mm; custom lengths up to 15 m
Packaging: Anti-rust oil, paper roll and wooden case; customizable options available

Certificates & Quality Testing
Supplied with certification and test reports on request. Typical documentation includes Material Test Certificate (MTC) for chemical and mechanical properties, ISO quality management evidence, third-party inspection reports (e.g., SGS, BV) upon request, GL approval for marine/offshore where required, and factory tests such as hardness verification (HRC 15–22), salt spray testing for plating corrosion resistance, ultrasonic testing for internal defects, surface inspection for chrome uniformity and roughness, straightness checks and dimensional measurement for tolerance compliance.

Technical characteristics

• Model family: 4140 chrome-plated rod
• Material: 4140 alloy steel
• Heat treatment: Normalized (HRC 15–22)
• Surface: Hard chrome plating, 20–30 µm
• Surface roughness: Ra ≤ 0.2 µm
• Tolerances: f7 / h8 (ID/OD options)
• Straightness: ≤ 0.2 mm/m
• Diameter range: Ø 6 mm – Ø 350 mm
• Length: Standard up to 8,000 mm; custom up to 15 m
• Packing: Anti-rust oil, paper roll and wooden case