Description:FIELD OF INVENTION

The present invention relates to roller chains such as industrial power transmission roller chains, conveyor roller chains which resist corrosion. The high corrosive resistance chains have the corrosion resistance over 1000 hours (Salt spray test conforms to ISO 9227). All components are made up of heat treated steel components with zinc nickel plating (Nickel content of 10% - 15%).

BACKGROUND OF THE INVENTION

Industrial Roller chains (ISO 606 standard) are used in wide variety of applications, from transportation to manufacturing. It offers a number of advantages over other types of chains, including ultimate tensile strength, dynamic strength, and resistance to wear. However, it can be susceptible to rust and corrosion, especially in damp or wet environments. The specialty high corrosive resistance chains are designed to withstand the rigors of corrosion-prone environments and are rust-proof, making them perfect for food processing, pharmaceutical, marine, and other corrosive applications. These roller chains are not recommended for chemical applications. The chain operating Temperature is -30°C to +130°C.

SUMMARY OF THE INVENTION

The high corrosive resistance roller chain consists of inner plate, outer plate, bush, roller and bearing pin. An inner link consists of two inner plates and press fitted with two bushes and two rollers loosely fitted on the bushes. Outer link consists of two outer plates and two bearing pins. Bearing pins are penetrated through the Inner link bushes. All components are heat treated and Zinc – nickel plating which thickness is minimum 8 micron.

The Zinc-nickel plating applied in all components level before the assembly of chain. The Zinc-nickel may also with a nickel content of 10 - 15%. Hydrogen Embrittlement process carried out in all plate components. In the process plate components will be baked a minimum of 3 hours at 375° F to relieve entrapped hydrogen.

BRIEF DESCRIPTION OF DRAWINGS

A brief description of the figures given below to get a better understanding the invention.

Figure 1 is an assembled view of high corrosive resistance simplex, duplex and triplex roller chains. All dimensions are according to ISO 606 standard. P - Chain pitch, d1 - Maximum roller diameter, b1 – Minimum width between inner plates, d2 – Maximum bearing pin body diameter, h1 – Maximum inner plate depth, h2 – Maximum outer or intermediate plate depth, Pt – Transverse pitch, b4, b5 & b6 – Maximum width over bearing pins of simplex, duplex and triplex chains, b7 – Maximum additional width for joint fastener.

Figure 2 Image of specialty high corrosive resistance chains before neutral salt spray test.

Figure 3 Image of specialty high corrosive resistance chains after neutral salt spray test. After 1000 hours of neutral salt spray test red rust spots founded. The spots are rounded in red color.

DESCRIPTION OF INVENTION

The invention relates to a load bearing roller chains in industrial application such as used in industrial power transmission. Such roller chains regardless amount of maintenance will gradually corrode. Hence the invention relates to a zinc-nickel alloy plating solution, particularly to zinc-nickel which provides good brightness and excellent corrosion resistance. Zinc-nickel alloy plates roller chains has extremely excellent corrosion resistance as compared to zinc plating and being particularly excellent in corrosion resistance an attempt for a wide range of environment temperature i.e., between -30°C to -130°C has been achieved in the invention.

The invention therefore proposes a plating solution composition such as the zinc-nickel composition which may have nickel content in the range 10-15% for plating all of the components forming the roller chain. The plated components are processed for hydrogen embrittlement which is baking the plated component at 375°F for a minimum duration of 3 hours.

The present invention provides a high corrosive resistance roller chain (simplex, duplex and triplex) which preserve its property of corrosive resistance for an extensive life more than thousand hours. The products were validated by neutral salt spray (NSS) test method based on ISO 9227 standard procedure.

The invention achieves to prepare a specialty high corrosive chains that have the corrosion resistance over 1000 hours (Salt spray test conforms to ISO 9227).

As per the invention process, all components can be heat treated steel components with special plating which form the roller chain.

The Special plating in the process is Zinc – Nickel coating with a nickel content of 10 - 15% as per invention, as the best result is achieved with this ratio.

These treated chains as per invention are found to be very suitable for food processing, pharmaceutical, Port equipment and other corrosive applications but these treated chains are not recommended for chemical applications.

The invention achieves the performance the operating temperature is -30°C to +130°C for the treated chains. Hence these treated chains as detailed above have a large scope of industrial application.

The invention has been described as detailed above but various embodiments and variations are possible beyond the preferred embodiments disclosed in this document. All such variations and modifications as obvious to the skilled person is within the scope of this invention.
, Claims:1. A process for treating industrial roller chains to improve corrosion resistance, the process comprising the steps of :

a. plating all the components of roller chain with zinc-nickel solution, in which the nickel content is in the range of 10-15%, and
b. releasing trapped hydrogen with hydrogen embrittlement by baking the plated components of step (a) for atleast three hours at a temperature of 375°F.

the said process characterised in that the sequence of plating is with a specific nickel ratio and further by baking the plated components and at the end of the process the plating thickness is atleast 8 microns.

2. An industrial roller chain which is zinc-nickel plated with nickel content of 10-15% to a thickness of atleast 8 microns and baked at 375°F for three hours to release the trapped hydrogen, the said characterised is that it is nickel zinc plated for a thickmess of atleast 8 mm and having a corrosive resistance over 1000 hours.