Chrome Plated C50 Rod (Quenched & Tempered)

The Chrome Plated C50 Rod (Quenched & Tempered) is manufactured from premium C50 medium carbon steel (1.0540 / 50#), processed with quenching and tempering (Q&T) before precision grinding and hard chrome plating. With a higher carbon content than CK45, C50 steel achieves greater strength and hardness after Q&T treatment while maintaining reasonable toughness, delivering superior core mechanical properties. This product is designed for heavy-duty, high-pressure hydraulic cylinders, heavy construction machinery, mining equipment and large-scale hydraulic supports where maximum core strength and wear resistance are essential—the ideal piston rod for demanding load-bearing and durability requirements.

• Diameter: Mainly φ6–300 mm, larger custom sizes accepted

• Length: ≤8000 mm, custom lengths available

• Straightness: ≤0.2 mm/M

• Tolerance Grades: IT6–IT9

• OD Tolerance: According to ISO f7/f8/g6/h7/h8/h9; customized tolerances available upon request

• Ovality: Half of the tolerance value ISO f7

• Heat Treatment: Quenched & Tempered; customization options include Induction Hardening and QPQ

• Core Hardness: 230–370 HB (typical hardness range for Q&T treated C50, can be optimized upon request)

• Surface Treatment: Hard Chrome Plated; customization options: EN Plating / Zinc Plating / Laser Cladding / Nitriding / QPQ / Thermal Spraying / Ceramic Coating

• Chrome Thickness: ≥10 μm, mainly 20–40 μm; can be over 100 μm for high-standard requirements

• Chrome Layer Hardness: 850–1150 HV (Vickers 100 gf)

• Surface Roughness: Ra≤0.2 μm, Rt≤2 μm

• Cohesion: No cracks, breaking or detaching after thermal shock (warming up at 300 ℃ and cooling in water)

• Porosity: Tested according to ISO 1456/1458, evaluation according to ISO 10289 rating 8–10. Under 10× magnification, no more than 30 micro white pin-holes per 1000 mm², with diameter not greater than approx. 0.1 mm

• Corrosion Resistance: Tested in neutral salt spray according to ISO 9227/ASTM B117 – 72 hours, rating 9 per ISO 10289

• Weldability: Fair (higher carbon content limits weldability; strict preheating, interpass temperature control and post-weld stress relieving are mandatory; welding in critical load-bearing areas should be avoided)

• Packing: Anti-rust oil + cardboard tube/plastic sleeve + wooden case

• Q&T treated C50 high-carbon steel achieves core hardness of 230–370 HB, providing significantly higher strength and deformation resistance than standard medium carbon steels

• Higher carbon content ensures excellent hardenability and compatibility with subsequent processes such as induction hardening or nitriding

• Hard chrome layer at 850–1150 HV delivers ultimate surface wear and scratch resistance through dual strengthening

• Tight f7 OD tolerance and low ovality ensure smooth motion and reliable sealing even under extreme pressure and heavy loads

• 72-hour salt spray test rated to class 9, meeting anti-corrosion demands in severe environments

• Can be combined with Induction Hardening or QPQ for a “high-strength core + ultra-hard surface” composite gradient

• Full customization of dimensions, hardness and surface finishing provides exclusive solutions for top-tier OEM products

In addition to standard specifications, we offer:

• Custom diameters and lengths, including large and extra-long sizes

• Tolerance grades and non-standard OD tolerances

• Higher straightness upon request

• Adjustment and optimization of core hardness range

• Combined heat treatments such as Induction Hardening or QPQ

• Surface treatment alternatives: zinc plating, electroless nickel, laser cladding, nitriding, thermal spray, ceramic coating

• Extra-thick chrome layers (can exceed 100 μm)

• Enhanced corrosion resistance and dedicated packing solutions

Limits and Fits Table

The table below provides shaft deviation values for commonly used tolerance grades f7, f8, g6, h7, h8, and h9 to assist your selection according to seal fits.

Chemical Composition

The table presents the standard chemical composition of frequently used materials such as CK45, 25Mn, 20#, ST52, 40Cr, 42CrMo4, 20MnV6 and 38MnVS6 for your reference.

Mechanical Properties

The following table lists reference tensile strength, yield strength, elongation and impact energy values for CK45 (hot-rolled, cold-drawn, Q&T), 25Mn, 20#, ST52, Q345D, 40Cr, 42CrMo4, 20MnV6 and 38MnVS6 under various conditions.