Material: 45#, 40Cr, 42CrMo, 16Mn, 304#, 316L
Diameter Range: Special specifications can be customized
Surface Hardness: Rc 55–65
Plating Thickness: 20 μm, 25 μm, 30 μm … 50 μm, etc.
Surface Roughness: Ra 0.2 μm ~ Ra 0.4 μm
Machining Accuracy: Tolerance f7, f8, g6, etc.
Length: 1000 mm to 6000 mm, customizable

Product Advantages

Superior Hardness and Strength: 

Made from high-quality steel, our chrome-plated rods have high hardness and strength, ensuring they can withstand heavy loads and stressful conditions.

Excellent Corrosion Resistance: 

Outstanding resistance to rust and corrosion, significantly extending the lifespan of the rods even in harsh conditions.

Smooth Surface Finish: 

The advanced plating process ensures a smooth and polished surface finish, reducing friction and wear on seals and other components, enhancing your machinery’s overall performance.

High-Tech Manufacturing: 

Each bar is precision-engineered to exact tolerances, guaranteeing perfect alignment and fit in all applications. This precision ensures optimal functionality and reduces the risk of mechanical failures.

Exceptional quality control: 

Magister Hydraulics bars are made of top-quality certified European steel, our manufacturing is operated under ISO Quality standards, guaranteeing the quality and accordance of every manufactured bar.

Hard chrome plated rods are precision techno components that are widely used in a wide range of industries. Hard chrome-plated rods are everywhere, whether it is about piston rods in the automobile industry, hydraulic pneumatics in pharma, or guide columns for plastic machinery. Therefore, choosing the best chrome-plated rods is crucial to ensure consistent quality in these industries.

Piston Rod — Advantages, Main Materials, and Surface Treatments

Advantages of Piston Rods

The manufacturing quality and processing technology of a piston rod directly affect its performance and service life.
Piston rods are typically processed using rolling technology, which enhances the surface corrosion resistance, delays the initiation and propagation of fatigue cracks, and thus improves fatigue strength.
In addition, rolling can reduce surface roughness and minimize wear, effectively extending the overall lifespan of the piston rod.

Main Functional Advantages

1. Cutting Clearance:
   Designed to compensate for wear of the packing rings.

2. Axial Clearance:
   Ensures that the packing rings can float freely; otherwise, the piston rod cannot operate properly.

3. Radial Clearance:
   Prevents the packing rings from being compressed or deformed due to piston rod sinking, thus avoiding damage.

Main Materials Used for Piston Rods

1. 45# Steel

45# steel is a high-quality carbon structural steel, commonly used in the manufacture of piston rods.
It has moderate hardness and good machinability. After quenching, the surface hardness can reach 45–52 HRC.
It also provides excellent machinability, strength, and toughness, making it one of the most widely used materials for shaft-type components.

2. 40Cr Steel

40Cr steel is a medium carbon alloy steel with excellent comprehensive mechanical properties.
It is suitable for manufacturing shafts that require medium precision, high rotational speed, and heavy load-bearing capacity.
In piston rod production, 40Cr is often used where impact resistance and high strength are required, ensuring reliable performance under heavy-duty conditions.

3. Stainless Steel (304, 316, 402)

Stainless steel piston rods are corrosion-resistant in air, steam, and water, offering excellent weldability, polishability, heat resistance, and corrosion resistance.
After precision cold drawing, fine grinding, and high-accuracy polishing, these rods meet or exceed standard technical requirements.
Therefore, stainless steel rods are widely used in hydraulic cylinders, pneumatic cylinders, and shock absorbers.

Surface Treatments of Piston Rods

1. Quenching and Tempering (Heat Treatment)

The purpose of quenching and tempering is to achieve an ideal combination of strength, hardness, plasticity, and toughness.
The microstructure after treatment becomes uniform fine-tempered sorbite, providing a good foundation for subsequent surface hardening.

2. Surface Hardening (High-Frequency Quenching)

Since piston rods operate under complex stress and frequent motion, they must possess high wear resistance and fatigue strength.
Therefore, high-frequency induction quenching is often used to achieve a surface hardness of 58–62 HRC.

3. Stress Relief Annealing

Because surface quenching uses the rod’s residual heat for tempering, the process may not completely eliminate internal stress.
Stress relief annealing before chrome plating is necessary to remove grinding and surface treatment stresses, ensuring stable performance.

4. Electroless Nickel-Phosphorus Plating / Alternative Coatings

Besides hard chrome plating, the surface of hydraulic piston rods can also be treated with electroless nickel-phosphorus plating for enhanced corrosion resistance.
For special applications, thermal spray coatings or ceramic layers can also be applied to meet specific performance requirements.