Manufacturing-Ruian Zhengji Motorcycle Parts Co., Ltd.

Material

Piston Material Piston Ring Material

Characteristics	Cast Piston	Forged Piston (4032 Alloy)	Forged Piston (2618 Alloy)
Process	Casting	High-pressure forging	High-pressure forging
Cost	Low	High	Very high
Weight	Heavy	Light	Extremely light
Strength/Toughness	Low	High	Extremely high
Wear Resistance	Excellent	Good (contains silicon)	Poor (requires special coating)
Coefficient of Thermal Expansion	Low	Lower	High
Applicable Clearance	Small	Medium	Must be very large
Daily Use	Perfect	Good (slight noise when cold-starting)	Poor (loud noise when cold-starting, requires warm-up)
Applicable Scenarios	Factory replacement, mild modification	Street performance, track day	Professional track, heavy modification

Ring Type	Base Material	Surface Treatment	Features and Application Scenarios
First Compression Ring	Steel	Molybdenum Spraying	Mainstream standard: Balanced performance, excellent anti-cylinder scoring ability, suitable for most family cars and performance cars.
	Steel	PVD (CrN/DLC)	Top-level high performance: Extremely low friction, ultra-high hardness, used in racing cars and high-performance engines pursuing power and efficiency. Expensive.
	Cast Iron / Steel	Chrome Plating	Heavy-duty and durable: Extremely wear-resistant, ultra-long service life, often used in diesel engines, commercial vehicles or designs focusing on durability. Slightly higher friction.
Second Compression Ring	Nodular Cast Iron	Phosphating or Nitriding	Economical and practical: Good oil scraping ability and sealing performance, low cost, used in medium and low-load engines.
Second Compression Ring	Steel	Nitriding	High-performance matching: Matches with the first steel ring to provide higher strength, used in high-speed or supercharged engines.
Oil Ring	Steel	Chrome Plating	Modern mainstream: Steel sheet oil scraping rings have become the absolute mainstream, with good elasticity and excellent oil scraping effect, widely used in all vehicle types.
Oil Ring	Cast Iron	Chrome Plating	Traditional design: Spiral spring cast iron oil rings are now gradually replaced by steel sheet rings.

Piston surface treatment process

The coating process on the piston surface is crucial to the performance, durability, and efficiency of an engine. Different parts (such as the skirt, head, and ring groove) operate in distinct environments and have varying requirements, so different coating technologies are employed.

Part	Coating Type	Main Material/Process	Core Function	Applicable Scenarios
Piston Skirt	Solid Lubricating Film	Graphite, MoS₂	Reduce friction, prevent scuffing, improve running-in property	Traditional process, general engines
	Tungsten Disulfide (WS₂) Coating	WS₂ Solid Lubricating Film	Reduce friction, high temperature resistance, oxidation resistance	Pistons, rings, pins under high-temperature conditions
	Tin Coating (Sn Coating)	Electroless Tin Plating	Improve running-in property, good oil affinity, prevent stagnation	Aluminum piston skirts
Piston Head	Hard Anodic Oxidation	Al₂O₃ Oxide Film	High temperature resistance, wear resistance, corrosion resistance, heat insulation	Piston heads of gasoline engines and diesel engines
Piston Head	Micro-arc Oxidation (Ceramic Layer)	Ceramic Layer (e.g., Al₂O₃)	High hardness, resistance to high-temperature impact, corrosion resistance	Piston heads of high-performance engines
Ring Groove Area	Ni-SiC Composite Electroplated Layer	Nickel-based Silicon Carbide Composite Coating	Enhance hardness and wear resistance	Aluminum piston ring grooves

Coating process

introduction

Ruian Zhengji Motorcycle Parts Co., Ltd.

Graphite Coating

A common solid lubricating coating applied to the piston skirt.

Tin Plating

It is mainly used for the piston skirt, aiming to greatly improve the initial running - in performance of the engine.

Anodizing

It is mainly used on the top (head) of the piston to form a hard, heat-resistant and insulating aluminum oxide ceramic layer.

Micro-arc Oxidation, MAO

It is also known as Plasma Electrolytic Oxidation (PEO), an advanced version of anodization. It is used to produce ceramic layers that are thicker, harder, and have stronger adhesion, and is mainly applied to piston crowns and ring grooves.

20 +

Industry Development Years

1000 +

Product Specifications

Piston manufacturing process