Chrome Plated 42CrMo Rod (Induction Hardened)

The Chrome Plated 42CrMo Rod (Induction Hardened) is manufactured from premium 42CrMo chromium-molybdenum alloy steel (AISI 4140 / 42CrMo4) in a non-heat-treated core condition. The surface is selectively hardened via induction hardening to produce a deep, extremely hard wear-resistant case, followed by precision grinding and hard chrome plating. With its chromium and molybdenum content, 42CrMo offers superior hardenability, achieving higher and more uniform surface hardness after induction hardening than standard alloy steels, while the core retains good toughness and machinability. This “ultra-hard surface + tough core” gradient is ideal for extremely abrasive, high-load, frequently reciprocating hydraulic cylinders in large mining equipment, construction machinery and heavy agricultural machinery—an optimal solution balancing extreme wear resistance and cost efficiency.

• 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: Induction Hardened; customization options include combined Q&T or QPQ

• Core Hardness: ≤260 HB (approx. 200–260 HB), non-heat-treated

• Surface Hardness: 55–65 HRC (after induction hardening; Cr-Mo alloy composition reliably achieves extreme hardness)

• 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 – 96 hours, rating 9 per ISO 10289

• Weldability: Very poor (high carbon equivalent severely impairs weldability; welding directly on the induction-hardened zone or HAZ is strictly prohibited; if welding is unavoidable, the hardened layer must be mechanically removed beforehand, with strict high-temperature preheating and immediate post-weld stress-relief tempering; welding in load-bearing areas must be absolutely avoided)

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

• 42CrMo chromium-molybdenum steel with superior hardenability achieves 55–65 HRC after induction hardening for top-tier wear resistance

• Non-hardened core retains toughness; adjustable case depth accurately matches severe wear conditions

• Hard chrome overlay (850–1150 HV) adds a second protective layer, providing ultimate safeguarding for seals and rod body

• Tight dimensional tolerances and minimal ovality ensure efficient sealing and smooth operation under heavy loads and ultra-high pressures

• 96-hour salt spray rating 9 provides reliable rust protection in highly corrosive industrial and marine environments

• Can be combined with Q&T or QPQ to achieve more complex core-surface property gradients for extreme operating conditions

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

• Tailored hardening depth and surface hardness range

• Combined Quenched & Tempered treatment for higher core strength

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

• Special chrome layer thickness

• 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.