​Screw Nitriding Treatment: A Key Surface Strengthening Technology for Enhanced Performance and Service Life

In fields such as mechanical transmission, plastic processing, and compression equipment, screws, as core working components, have their surface performance directly impacting the stability and service life of the equipment. In recent years, ion nitriding (also known as plasma nitriding) technology has been widely used in the surface treatment of high-performance screws due to its significant performance improvements, stable process, and environmental friendliness.

This article will systematically introduce the main advantages of screws after ion nitriding treatment from the aspects of technical principles and performance characteristics, helping readers to more comprehensively understand the application value of this key process.

Overview of Ion Nitriding Technology Principles

Ion nitriding is a process in which nitrogen gas is ionized through glow discharge in a vacuum environment, forming highly active nitrogen ions. Under the action of an electric field, nitrogen ions bombard the screw surface at high speed and diffuse into the base material, ultimately forming a dense and stable nitride layer on the surface. Common structures include Fe₄N, Fe₂–₃N, etc.

This nitride layer forms a metallurgical bond with the base material and is not easily peeled off, which is an important foundation for improving the overall performance of the screw.

High Surface Hardness and Excellent Wear Resistance

After ion nitriding, a high-hardness hardened layer can be formed on the screw surface, with a microhardness typically reaching HV 800–1200, significantly higher than the untreated state.

This high-hardness surface layer is particularly advantageous in the following working conditions:

High-speed rotational operation

Long-term continuous operation

Heavy load or high friction conditions

The treated screw can effectively slow down the wear rate and extend the service life, thus reducing frequent replacement and downtime maintenance problems caused by wear.

Excellent Corrosion Resistance

The nitride layer has good chemical stability and can form an effective protective barrier on the screw surface, providing strong resistance to various corrosive media, including:

Water vapor and humid environments

Lubricating oils and industrial oils

Certain concentrations of acid and alkali media

Therefore, screws treated with ion nitriding are more suitable for chemical, marine environments, or high-humidity working conditions, helping to reduce the risk of corrosion failure and improve the reliability of equipment operation in complex environments. 

Enhanced Fatigue Strength and Crack Resistance

During the ion nitriding process, beneficial residual compressive stress is introduced into the surface layer of the screw. This stress state effectively suppresses the initiation and propagation of microcracks, significantly improving the fatigue strength of the component.

This characteristic is particularly important for transmission systems subjected to cyclic loads or frequent starts and stops, reducing the probability of unexpected fracture and improving overall operational safety.

Excellent Dimensional Stability and Precision Retention

Compared to traditional high-temperature heat treatment processes, ion nitriding is performed at relatively lower temperatures, generally controlled within the range of 400–580℃. This feature offers significant advantages:

Low thermal deformation

Controllable dimensional changes

Excellent geometric precision retention

Screws typically do not require further machining after nitriding, effectively reducing manufacturing costs, and are particularly suitable for precision mechanical components requiring high dimensional accuracy.

Environmentally Friendly, Efficient, and Widely Applicable

The entire ion nitriding process is carried out in a sealed vacuum environment, with no harmful gas emissions, meeting the current manufacturing industry's requirements for green and environmentally friendly processes. Furthermore, this process has the following characteristics:

Relatively low energy consumption

Controllable processing cycle, suitable for mass production

Applicable to a variety of materials, such as alloy steel and stainless steel

Brand Product Recommendation 

EJS Single Screw Barrel

Available Inner Bore Size Range

EJS. offers single-screw extruder barrels in various specifications with a wide range of inner bore diameters to meet different production capacity requirements:

While high-performance screw surface strengthening technology continues to develop, the material selection, manufacturing precision, and heat treatment process of the barrel body also determine the overall operating efficiency and service life of the equipment.

Item	Parameter Range
Barrel Inner Hole Diameter	Φ12 mm – Φ500 mm
Applicable Process	Extrusion / Injection Molding
Customization Method	By Drawing or Joint Design