FIELD OF THE INVENTION

The present invention relates to the field of ring travellers for the textile spinning mills. More particularly, the present invention relates to a steel boronizing composition for ring traveller and diffusion process thereof. Advantageously, the present invention provides for an improved wear resistant ring traveller by modifying microstructure through a heat treatment process.

BACKGROUND OF THE INVENTION

Ring traveller is the most tinny and simple mechanical element in ring frame. It has a direct effect on the quality of yarn produced as their action physically turns the raw material into finished product. So, ring traveller plays very important role in ring spinning system. Ring and traveller do have an effect in particular on yarn hairiness. The wear condition and the centering of the ring play a primary role. A worn ring surface always results in increased yarn hairiness results. Increasing the wear resistance of the traveller remains an immense challenge due to the high mechanical and thermal stress experienced by travellers during the spinning operation. Due to this exposure, surface deformation, such as scratches and diffusion deformations, are unavoidable.

Hence, the present invention aims to provide a steel boronizing composition for ring traveller and diffusion process for improving the wear resistance of ring traveller by modifying microstructure through a heat treatment process.

US4677817A discloses a traveller for spinning mills made of hard drawn steel wire or alloy steel wire with a ceramic coated layer composed of a single layer of carbide, nitride, oxide or boride or composed of a composite ceramic coated layer formed by dispersing ceramic grains with Ni alloy, Ni, Cr, Co, etc as a matrix.

US6804943B2 A ring traveller for ring Spinning or ring twisting machines, comprising an iron core wherein at least one mechanically stressed part of the core has a nitride edge layer, and wherein the edge layer includes a connecting layer and a diffusion layer, whereby the connecting layer has a thickness of 8 pm -12 pm and the diffusion layer (24) has a thickness of 100 pm to 200 pm. Wherein nitriding agent is Supplied in the form of a gas comprising NH and N components, a nitrogen-enriched liquid or a nitrogen-enriched plasma.

IN1108/CHE/1995 discloses a spinning ring for a ring spinning frame characterized in that atleast at the contact surfaces of the spinning ring with the traveller a metal - phosphoric layer is applied, with a content of 1-4% phosphor or a metal -boron layer with 0.5 - 4% boron.

US7096656B2 discloses a ring traveller and method for producing it. The covering layer in this case contains fine crystalline chromium nitride, vanadium carbide or titanium carbonitride.

US20190233981A1 disclose a having a metallic core, wherein the metallic core is at least partially coated with an anti friction coating consisting of at least a base polymer and a solid lubricant, whereby the anti - friction coating has a layer thickness of 0.1 um to 50 um and the base polymer is from the group of polyamides, polyimides, polyamide / imides.

EP3052684B1 discloses a ring for a ring spinning machine, comprising a metallic core and a metallic coating applied on the core, characterized in that the metallic coating is designed as atleast one hard chrome dispersion layer composed of chrome having intercalated hexagonal boron nitride, wherein the boron nitride has mean particle size of 4 m /g to 30 m /g.

US5086615A discloses a coating on the surface of the ring traveller, said coating being chemically deposited thereon and being uniform in thickness of from about 0.1 mil to about 0.5 mil, said coating including from about 15% to about 30% by volume of a particulate polytetrafluoroethylene uniformly dispersed in a metallic matrix including a nickel-phosphorus alloy, each fluorocarbon particle being in a size on the order from about 0.002 mil to about 0.02 mil.

US10385480B2 discloses a textile spinning traveller, comprising a base material; an undercoat layer deposited on the base material; and a metallic sulfide coating deposited on the undercoat layer, wherein the metallic sulfide coating comprises tungsten disulfide, wherein the undercoat layer comprises one or more black oxide, nitride steel, manganese phosphate and chromium.

IN1905/CHE/2008 discloses a ring traveller having a core and surface coating comprise one or more layers of nano-oxide ceramic, nano-nitride ceramic, nano-carbide ceramic. US4555326 discovered that if hydrocarbons are processed in metallic equipment which have been previously boronized, that coke formation and deposition which is commonly experienced at high temperatures can be minimized if not totally eliminated. The compositions utilized for this purpose are comprised of boron or boron compounds contained in an organic solvent or carrier together with specific activating materials.

The existing prior process applied for spinning machines parts and dies, most of the inventions used SS and Q245 material for processing, temperature between 900 - 1400°C, percentage of chemical mixture is lower side, layer thickness specified for above 100 microns, only for wear and corrosion resistance and does not apply for elongation property.

Hence, there is a need for a process applied in ring traveller for spinning mills, the present invention uses a low alloy and high carbon steel tube, a temperature between range of 850 - 950 degree Celsius, percentage of chemical mixture is higher side, layer thickness specified for above 10 to 20 microns, with improved wear resistance and co-efficient of friction and process designed for obtaining elongation property.

OBJECT OF THE INVENTION

It is the primary object of the present invention to provide a boronizing composition for steel ring travellers and process for improving the wear resistance of ring traveller by modifying microstructure through a heat treatment process.

It is another object of the present invention to improve the ring traveller performance and life by modifying the microstructure through a special heat treatment process to improve the wear resistance.

It is still another object of the present invention to provide an improved wear resistant steel boronizing composition or boronized steel composition for ring travellers to improve the productivity by reducing the number of change over.

It is yet another object of the present invention to provide an improved ring traveller with boronizing steel slide surface with layer thickness range between 10 - 20 microns. SUMMARY OF THE INVENTION

One or more of the problems of the conventional prior arts may be overcome by various embodiments of the present invention.

It is a principal aspect of the present invention to provide a ring traveller, comprising a steel core and wherein the surface part of the core has a borided layer, wherein the borided or boronized layer comprises iron boride FeB and FeB2.

It is a another aspect of the present invention to provide a ring traveller, wherein the boride layer formed on the surface of the ring traveller comprises iron borides FeB, FeB2, with a layer thickness in the range of 15 and 40 microns, core hardness 300 - 450 HV, and surface hardness 900 - 1100 HV

It is a another aspect of the present invention to provide a ring traveller, wherein the boronized layer is reinforced by means of inert filler selected from silicon carbide; primary activators selected from sodium carbonate (NaoCCF), Sodium tetraborate (N 306407), KB4 and combinations thereof; and secondary activators selected from diluted alumina, SiC and mixtures thereof.

It is another aspect of the present invention to provide a boronizing composition for ring traveller having a steel core, wherein the composition comprises on a percentage by weight basis, boron source / agent - 1 - 6% ; inert fillers - 2 - 5%; primary activators - 2 - 5%; and secondary activators - 60 - 90%, wherein the boron agent is Boron carbide (B4C), and wherein the boron carbide has a particle size of 5-9 microns.

It is another aspect of the present invention to provide a boronizing composition for ring traveller having a steel core, wherein the inert filler is Silicon carbide (SiC).

It is another aspect of the present invention to provide a boronizing composition, wherein the primary activators are selected from sodium carbonate (NaoCCF), Sodium tetraborate (Na2B40), KB4 and combinations thereof to make up to 100%. It is another aspect of the present invention to provide a boronizing composition, wherein the secondary activators are selected from diluted alumina, SiC and mixtures thereof.

It is another aspect of the present invention to provide a method of preparing a boronized ring traveller having a steel core, comprising steps: subjecting non-coated core to a heat pre-treatment at a temperature range between 900 and 950 °C in a reaction chamber for a period of 2-6 hours; and boronizing the core; wherein boronizing the core comprises: preparing boronizing composition comprising boron agent, inert fillers, primary activators and secondary activators and subjected to pre -heating at 650 °C for a time period of 30-45 min; raising the temperature to 800-850°C for a period of 15-20 min; further raising the temperature to 850-950°C to for a period of 2 - 6 hours; and subjecting to alkaline quenching at a temperature of 400°C to yield a boronized ring traveller.

It is another aspect of the present invention to provide a method of preparing a boronized ring traveller having a steel core, wherein the boronizing composition is supplied in the form a gas, liquid or paste.

It is another aspect of the present invention to provide a method of preparing a boronized ring traveller having a steel core, wherein the thin boride layer formed on the surface of the ring traveller as iron borides FeB, FeB2, with a layer thickness in the range of 15 and 40 microns, core hardness 300 - 450 HV, and surface hardness 900 - 1100 HV.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the features, advantages and objects of the invention, as well as others which will become apparent, may be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiment thereof which is illustrated in the appended drawing, which form a part of this specification. It is to be noted, however, that the drawing illustrate only a preferred embodiment of the invention and is therefore not to be considered limiting of the invention's scope as it may admit to other equally effective embodiments.

Figure 1 illustrates the hardened or non-heat treated steel ring traveller after boronizing process according to one embodiment of the present invention.

Figure 2 illustrates the hardened or non-heat treated steel ring traveller after boronizing process according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to the field of ring travellers for the textile spinning mills. More particularly, it relates to a boronizing composition for steel ring traveller and diffusion process thereof. Advantageously, the present invention provides for an improved wear resistant ring traveller by modifying microstructure through a heat treatment process.

The ring traveller according to the invention has a non-coated core which consists of steel material and which is heat treated in a boron atmosphere resulting in thermal diffusion of boron into the steel. This process is called boronizing, this diffused layer offers hardened surface and improves the wear resistance.

The objective of the present invention is to improve a ring traveller life for ring spinning or ring twisting machines, which, further-improved running and operating properties and also reduce the wear and tear of the ring itself.

A ring traveller according to the invention has a non-coated core comprised of steel material and consists of boronizing layer throughout the surfaces with which said core slides on a ring of a ring spinning or ring twisting machine or in which the yarn is guided.

By the composition of the boron agent being controlled according to the invention and by an appropriately selected treatment parameters including temperature - time profile, the elasticity of the ring traveller to be secured the traveller free of deformation, onto spinning rings, can be maintained. The core is heated to a temperature in the range of 900°C - 950°C, and is maintained in said temperature range for 2-6 hours. The boron agent may be supplied in the form of a gas, liquid or powder preferably consisting of halogen carrier and diluted thermal activator components. The boronizing layer of the ring traveller core consists of without an additional diffusion layer; the layer has preferably a thickness of up to 25 microns. However, diffusion thickness can be controlled based on requirement. The carrier agent has halogen, in addition to the boron components and some diluted thermal diffuse activator components being added. At the same time, the thicknesses of the diffusion layer can be controlled by soaking time, as required.

According to the aspect of the present invention, there is provided a ring traveller with core and a coating / diffusion layer comprising of boron agent preferably selected from 1 - 6% of Boron carbide (B ₄ C), with a mean particle size in the range of 5 - 9 microns.

In addition, the diffusion/ borided layer composition according to the present invention is reinforced with inert fillers selected from of Silicon carbide; primary activators selected from sodium carbonate (Na ₂ COs), Sodium tetraborate (NaoBAT), KB ₄ and combinations thereof; and secondary activators selected from diluted alumina, SiC and mixtures thereof.

According to a preferred embodiment of the present invention, the boronizing composition comprises on a percentage by weight basis: Inert filler - 2-5%; primary activators - 2-5%; and secondary activators - 60 - 90%.

Preparation of a ring traveller as per the present invention comprises a two-step reaction process:

The first step reaction is between the boron yielding substance or boronizing composition and core that need to be coated by the boronizing composition. In preferred embodiment the core comprises of a steel ring traveller and the coating is the boronizing layer. The nature of the coat is a function of time and temperature. This results in a thin dense boride layer. This reaction is followed by diffusion, which is a faster process.

The boronizing is a special mixture of chemical compounds boron carbide as an active source and additionally SiC used as an inert filler, sodium carbonate (NaoCCT), Sodium tetraborate (Na ₂ B ₄ 0y) added for the activator in the mixture percentage of 40:30:30, in addition to the boron components and 60 - 90% diluted alumina to be added as additional / secondary activator starts the diffusion process at 800 - 860 degree Celsius, boride atoms will subsequently diffuse into the work piece. The core part of the ring traveller is heated to a temperature in the range of 900- 950°C, and is maintained in said temperature range for 2-6 hours. The boron agent may be supplied in the form of a gas, liquid or powder preferably consisting of thermal activator components (sodium carbonate (Na2COs), Sodium tetraborate (NaoE^CT), and KB4.

The embodiments of the present invention are further provided as examples below.

EXAMPLE 1:

The steel ring traveller used for experimental procedure has the composition of 97% - Iron; 1% carbon; 0.5% chromium; 0.5% manganese; 0.2% sulphur; and 0.15% phosphorus.

The ring traveller comprises steel material of the above mentioned composition and which is heat treated in a boron atmosphere resulting in thermal diffusion of boron into the steel. The boronized coating is a coating that covers the surface part of the core and composed of borided layer, wherein the borided or boronized layer comprises iron boride FeB and FeB2. The boronized layer has a thickness in the range of 15 and 40 microns, core hardness 300-450 HV, and surface hardness 900 - 1100 HV. The boronized layer also called diffused layer offers hardened surface and improves the wear resistance.

For boronizing, a boronizing composition is used comprising on a percentage by weight basis, boron source / agent - 1 - 6% can be any boron agent, inert fillers - 2 - 5%, primary activators - 2 - 5%, secondary activators - 60 - 90%, example for a boron agent is Boron carbide (B4C) of particle size of 5-9 microns.

The boron mixture is prepared with all required additives such as inert filler, primary and secondary activators in a liquid or a paste form, the part is immersed in to the liquid or paste and heat treated using a furnace at a temperature range between 850 - 950 degree Celsius, until the boron react with the steel part surface and gradually started to penetrate in to the surface. The size of layer depends upon the soaking time and as per the requirement.

The boronized layer is reinforced by means of inert filler selected from silicon carbide; primary activators selected from sodium carbonate (NaoCCT), Sodium tetraborate (Na2B C)7), KB4 and combinations thereof; and secondary activators selected from diluted alumina, SiC and mixtures thereof. Inert filler is also selected from alumina or SiC. Process:

The chemicals are mixed as per the given percentage to form a paste, the steel ring traveller or the part of the traveller to be coated is immersed in the paste and loaded in to the oven, preheated by 650°C for 30-45 minutes. Then the temperature raised to 850°C followed by soaking for 15-25 minutes. Then the temperature is raised to 900-950°C maintained for 2- 6 hours. After completion of the process the temperature is reduced to 400 degree Celsius then quenched using an alkaline bath tank.

EXAMPLE 2:

In another exemplary embodiment, the boronizing composition is supplied in the form of reactive gas in a reaction chamber for coating of ring traveller surface.