Chrome Plated C50 Rod (Q & T + I.H.)

The Chrome Plated C50 Rod (Q & T + I.H.) is produced from premium C50 high-carbon steel (1.0540 / 50#), processed with dual heat treatment—Quenched & Tempered plus Induction Hardened—followed by precision grinding and hard chrome plating. Q&T treatment gives the core a high-strength, tough matrix at 240–370 HB, while induction hardening produces an ultra-hard surface layer of 55–64 HRC at a controlled depth of 0.5–3.5 mm. Topped with a 850–1150 HV hard chrome deposit, the higher carbon content of C50 delivers superior hardenability and surface hardness compared to CK45, creating an “ultra-strong core + ultra-hard surface” extreme gradient. This flagship piston rod is engineered for the most demanding heavy-duty cylinders—large mining equipment, deep-sea applications, ultra-high-pressure construction machinery—where maximum durability is essential.

• 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 + Induction Hardened; customization options: Q&T only, I.H. only, QPQ, etc.

• Core Hardness (Q&T): 240–370 HB

• Surface Hardness (I.H.): 55–64 HRC

• Hardening Depth: 0.5–3.5 mm (adjustable)

• 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: Poor (high carbon content severely limits weldability; welding on the induction-hardened zone should be avoided; pre-weld machining to remove the hardened layer and strict preheating and post-weld stress relieving are mandatory)

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

• C50 high-carbon steel with dual heat treatment achieves the ultimate “high-strength tough core + ultra-hard surface” gradient

• Q&T core at 240–370 HB delivers superior bending, impact and fatigue resistance with best-in-class load-bearing capacity

• Induction-hardened surface at 55–64 HRC with adjustable depth provides extreme wear and indentation resistance

• Hard chrome overlay (850–1150 HV) adds a second wear-resistant shield, offering final protection for extreme service conditions

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

• 72-hour salt spray rating 9, combined corrosion protection for the harshest environments

• Fully customizable dimensions, hardness profiles and processing to serve flagship OEM applications

In addition to standard specifications, we offer:

• Custom diameters and lengths, including extra-large sizes

• Tolerance grades and non-standard OD tolerances

• Higher straightness upon request

• Tailored combination of core hardness and induction-hardened case hardness

• Precise control of hardening depth

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

• Extra-thick chrome layers beyond 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.