1. Surface performance enhancement: Hard and wear-resistant, tough and fatigue-resistant
high-frequency quenching utilizes electromagnetic induction to heat the piston rod surface to the quenching temperature (approximately 1,000–1,020°c) in an extremely short time (typically seconds to tens of seconds), followed by rapid cooling (e.g., compressed air spraying or water cooling). This forms a quenched layer with a depth of 1.5–2.5 mm, composed of martensite with a hardness of ≥ hrc 50 (up to hrc 58–62 for high-end products), while the core retains the tough structure of tempered or normalized steel. This “Hard surface, tough core” Characteristic provides the following advantages:
Enhanced wear resistance: The quenched layer effectively resists friction and wear, extending service life. For example, in hydraulic cylinders of engineering machinery, the service life of high-frequency quenched piston rods is 3–6 times longer than that of ordinary piston rods.
Improved fatigue resistance: The compressive residual stress generated after surface quenching inhibits crack propagation, enhancing fatigue fracture resistance. In automotive shock absorbers, high-frequency quenched piston rods can withstand higher-frequency reciprocating motions without failure.
Corrosion resistance improvement: For some products (e.g., stainless steel piston rods), high-frequency quenching forms a dense oxide layer on the surface, further enhancing corrosion resistance for harsh environments such as chemical and marine applications.
2. Significant process advantages: Efficient, precise, and environmentally friendly
compared to traditional quenching methods (e.g., flame quenching, salt bath quenching), high-frequency quenching offers the following technical advantages:
Localized heating, minimal deformation:
Only the surface is heated, with minimal temperature change in the core. Deformation can be controlled within 0.05 mm/m, meeting high-precision assembly requirements. For example, in semiconductor vacuum pipelines, the straightness error of high-frequency quenched piston rods is ≤ 0.1 mm/m, ensuring sealing performance.
Rapid heating, high efficiency:
Induction heating speeds can reach 100–300°C/s, far exceeding traditional methods (≈10–50°C/s), significantly shortening production cycles. An 80 kW high-frequency furnace can process 50–100 piston rods per hour, making it suitable for mass production.
Strong process controllability:
Parameters such as inductor power, heating time, and cooling methods can be adjusted to precisely control the depth, hardness, and microstructure of the quenched layer. For example, 45# steel piston rods use polyethanol water-soluble quenchants, while 2Cr13 stainless steel piston rods use 0.1–0.2 MPa compressed air spray cooling for differentiated treatment.
Environmental friendliness and energy efficiency:
The heating process produces no open flames or smoke, aligning with green manufacturing standards.
Electrical energy utilization rates reach 80%–90%, saving 30%–50% energy compared to traditional salt bath furnaces.