Factors for Thermal spray wire material selection

Wire is a recommended feed material for diverse coating operations because of lower material cost and easy handling. The wire operations are usually featured by high deposition rates and great efficiency. The common applications for thermal spray wire is the combustion wire process and wire arc spray process which uses total pounds of wire per year when compared to combustion wire.

The applications include the coating materials that can be developed into a malleable wire.

The wire production process is what limits what materials you can develop in thermal spray wire. The basic process includes forging or hot rolling to a moderate size. The eventual processing needs cold drawing uses hardened dies that also includes heat processing procedures to avoid cold process from the drawing process. In case of extremely hard or brittle material for cold drawing, it may not as thermal spray wire.

Wires are classified as base material, the metal that is predominant in wire. The wires for electric arc and combustion spray includes aluminium, cobalt, copper, iron, molybdenum, nickel, zinc and tin. Titanium wire is used for electric-arc spray however not combustion arc spraying as titanium has a higher melting temperature that is available with combustion spray. Lead wire is recommended for combustion spray however not electric-arc spray due to low electric conductivity of lead.

A key factor is the wire size. In various industries, wire sizes are usually expressed as gauge. Although, there are several conflicting definitions of gauge, wire gauge, US standard for stainless steel. AWG is utilized for non-ferrous wire and SWG is utilized for ferrous wire. As it is important to have a close match between the thermal spray gun set-up and the wire size, it is preferred that wire size is specified in mm instead in gauge.

Wire feed for spray systems

Wire feed is crucial for any wire based thermal spray operation. A single wire feed is preferred for flame spray systems while twin wires are specifically utilized for electric arc spray systems. The generic wire produced for other industries can cause major grief. Standard industrial wire may have surface scaling that result to wire feed jams, extensive wear of feed components and result to inclusions in the final coating. Additionally, other industries may not be related with offering wire rolls free of kinks, weld joints or other characteristics that could lead to feed issues. Many wires have lubrication added to the surface during the even spooling process. The level winding process is used during the spooling process that is a method of wire coiling on the spool so it is wound single level layer.

In establishing the wire feed system, sufficient space is required to permit for free wire feeding without binding. It is particularly essential for wire guns that utilize a pull drive only. The wire-straightener system in the feed is also advantageous for smooth and trouble-free thermal spray operation. When wire is wound, it releases the spool without getting tangled.

Moreover to solid wire, there is certainly hollow wire filled with powder. These are recommended as cored wires in that they have a hollow core filled with powder. These are preferred as cored wires in that they have a hollow core filled with powder. 

Use of highly adaptable and heavy duty Mesh trays in industries

A mesh tray acts an effective and consistent support for cables. The mechanical function of mesh tray products ensures that they safely support wires in a wide range of applications. We manufacture the tray systems that offer one-step locking and do not need extra hardware to secure the support. The mesh trays are designed to support any load.

Mesh Material Type

To receive the best performance from mesh tray, it is essential to choose the right metal mesh to provide good corrosion resistance and mechanical strength. Corrosion is an uncontrollable and recurrent problem in all applications that involve the use of metals. It may adversely affect the performance and lifetime of the device. The trays are widely exposed to atmospheric corrosion, so the conditions in which the trays functions is a crucial factor in the choice of metal. Atmospheric corrosion reduces the performance of metals due to in reaction between air/ water/ moisture/ rain and metal surface.

The mesh tray has main applications in Building services, infrastructure, heavy industry and processing plants.

Full Food safety

The smooth mesh minimizes the chance of entrance of dust and particles on the surface. Whether used horizontally or sideways, mesh offers easy inspection of the food to confirm that it is clean. Any foreign material or bacterial growth can be found in the initial stage

The pollution or unknown production can be prevented by blowing, vacuuming and power cleaning. These steps can be followed regularly or after inspection. In Sideway installation, the chances of dust and debris accumulation on the mesh surface widely decrease.

Adaptable Trays

Easily adaptable Nichromemesh trays and steel mesh trays are fit for any installation method. The premium mesh tray has the wide contribution in the food industry.  Nichrome and stainless steel mesh are also highly corrosion resistant therefore they offer longer performance than traditional materials.

Protection from electric shocks

Irrespective of the electrical security of the equipment, energy flow is always risky to people and their belongings. Therefore we test the trays for short circuits before their delivery. The mesh tray is subjected to large mechanical stress for some time and the process is repeated to confirm that the mesh structure is able to deal with the short circuit.

The mesh trays are also fire resistant. The mechanical properties of the wires and mesh tray ensure the durability of the installation for a required time period.

Nichrome mesh tray is constructed of precision engineered and high quality mesh and is the result of wide experience gained from the manufacturing of the large magnitude of mesh tray across the globe.  The mesh tray has performed in the various applications varying from heavy power pathways on oil drilling units to electrical and data installation in the advanced office buildings.  

Various applications of Nichrome mesh tray include thermistor sintering, silver sintering, semiconductor sintering, ceramic capacitor, chip sensor sintering, battery anode and photovoltaic wafer sintering. Nichrome mesh offers good heat resistance and corrosion resistance by which it performs for a long term in the various application media.

Use of Monel 400 and Inconel 600 in chlorinated application media

Chlorinated hydrocarbon solvents are greatly used in dry cleaning, metal degreasing a great range of solvent extraction procedures in the chemical plants. When water is eliminated and at natural temperatures, the solvents are not attacking and steel equipment can be used to deal them. However of entrained water or water layer and specifically at the elevated temperatures that occurs in distillation and recovery of solvents, the essential hydrolysis with development of dilute hydrochloric acid.

The development of acidity is increased by nominal light and aeration. The steel is sharply attacked. For a great service of numerous years, Monel 400 and Nickel have offered supreme resistance to corrosion in these media of a great range of chlorinated hydrocarbons. The alloys are utilized for distillation and recovery equipment in the development and application of solvents.

In the development of chlorinated solvents while their development, the corrosive conditions are very vigorous in the static media or reboiler in the edge parts of distilling columns where water accumulates. Monel 400, Nickel and Inconel600 wire provide high resistance to corrosive media, these alloys are used for distillation and recovery equipment in the development and service of solvents.

An evaluation of resistance offered by metals and alloys to corrosion by different chlorinated solvents and mixtures of the solvents with water at room and boiling temperatures.  In the refinement of chlorinated solvents while their development, the corrosive media are harsh in the static or reboiler or in the edge segments of distilling columns where water deposits. It is discovered by the results of plant corrosion evaluation in regular process for refinement of crude carbon tetrachloride.

The main applications of Monel 400 and nickel are in the development of dry cleaning systems, for components need in solvent recovery stills and condensers, washer cylinders, water distillation, lint traps and solvent storage containers. These equipments use a wide range of solvents like carbon tetrachloride, trichloroethylene, perchloroethylene and solvent mixtures.

For metal degreasing applications, various chlorinated solvents are used including trichloroethylene, carbon tetrachloride, perchlorethylene, ethylene dichloride, propylene dichloride and more. Monel 400 and Nickel are used for degreasing containers and solvent recovery equipments.

In the solvent use of animal and vegetable oils, various chlorinated solvents are used. Monel 400 is used for solvent recovery equipment for cod liver extraction using ethylene dichloride.

A large count of organic chlorination is in the set of dry raw materials. For organic chlorination, Monel 400 and Inconel 600 are used. They offer good corrosion resistance and have no catalytic influence on the color of the product.

About Manufacturer

Heanjia Super-Metals is a premier supplier of corrosion resistant super alloys that offer supreme performance for a long term. We produce nickel based alloys that are widely used in the severe application media such as in chemical and petrochemical, oil and gas, aerospace and land based gas turbines. These alloys have been in service for several years and are gradually used in the advanced applications to meet the challenging corrosion resistance demands of the industries in the modern time.

Use of filter discs in metallurgical industries

The disc filters have common applications in heavy duty processes for example dewatering of iron, copper concentration, floats concentration and other industrial processes. The filter discs were extensively used in 60s in the metallurgical plants.

The filter is made of many discs about 15 in the large size equipments, each part consists of sectors that are joined together to build the disc. The benefit is that disc filters cover nominal floor space and cost per operation is much lower as compare to vacuum filters.

Filter disc in operation

During the operation, every sector enters submergence and a cake is developed on the face of discs. It then emerges to the drying region, the liquid drains to the middle barrel from there via a valve to the vacuum receiver. The valve monitors the timing so that as soon as sector exits the drying region, it goes over a separation bridge and a snap or low pressure blow is applied to cake discharge. Scraper blades on every disc side direct the cake to discharge chutes that are located between adjacent discs and are sufficiently wide to prevent clogged by dropping cake. An agitator positioned at the end of tank collect slurry in suspension that in other metallurgical processes collects solids with high specific gravity that are abrasive.

Other disc filter types

Disc filters can serve as vacuum disc filters or pressurized disc filters. Due to differential pressure application on both sides of Hastelloy mesh filter discs, the effective filter area is significantly larger than drum filter for the same floor area.

Pressurized disc filters:

a.       Pressurized disc filter involves the application of lower pressure gas to the slurry side

b.      The compressed gas develops the essential pressure differential for filtration

c.       The filter is configured in an air-tight housing.

d.      Filtration starts when the disc quits the slurry

e.      Internal valves and piping channel the filtrate far from all discs and towards a receiver.

f.        The filter housing is created to comprise of a redistributed process gases. It can be developed from different materials.

Vacuum Disc Filters

a.       Cake development: An internal valve opens that allows vacuum creation inside the filter screen. The cake develops on a part of the submerged drum

b.      Cake drying: With the rotation out of slurry by the slurry, the drying process starts. Vacuum is applied to develop a pressure differential essential to discard the filtrate.

c.       Cake Discharge: An internal valve locks the vacuum at this level. The discharge processes can be a scraper belt, belt or roll. The compressed air is used to eradicate the cake from the filter screen.

Precoat disc filters

A Precoat disc filter performs as vacuum disc or a pressurized disc filter.

Capillary Action disc filters: These filters are used to dewater mineral concentrates and pelletize the feed slurries.  The porous disc replace the traditional filter cloth. The capillary action draws liquid through pores and a small size vacuum pump is needed that significantly lowers the energy consumption. 

Service environments in Paper and Pulp industry

Paper is developed by digesting wood chips with a combination of sodium sulphite and NaOH. The product is sent to the brown stock washers to eradicate the liquor from the brown pulp. Subsequent to screening, pulp go directly to the paper mill to develop unbleached paper, or it is directed first to the bleach plant to develop white paper.

The digester vapors are condensed and the condensate is pumped to brown stock washers. The black liquor from these washers is concentrated and heated with sodium sulfate to recover sodium carbonate and sodium sulfide. With water dissolution, the green liquor is processed with calcium hydroxide to develop sodium hydroxide to replenish the white liquor. Pulp bleaching includes treatment of different chemicals such as chlorine, chlorine dioxide, peroxide, caustic soda, quicklime or oxygen.

The sulphite processes utilize a liquor in the digester that is unlike to that used in kraft process. This liquor consists of free SO2 dissolved in water with sulfide dioxide as bisulfite. The chemistries of the specific liquors is different. Sulfur dioxide for the cooking liquor is developed by burning elemental sulfur , cooling quickly, absorption of SO2 in a weak alkaline solution and strengthen the raw acid.

Different alloys are chosen for various corrosive media occurring in pulp and paper mills. The mill headboxes are usually produced from stainless steel 316 plate with excellent surface finish and electropolished to avoid scaling that may affect pulp flow.

The evaporators and reheaters handle the severely attacking liquors and should decrease scaling to develop adequate heat flow. Stainless steel 304 welded tubing is used in kraft black liquor evaporators. Cleaning is usually performed with HCl that attacks ferrite. In the sulphite process, stainless steel 316 is used in black liquor evaporators. Digetester liquor heaters in the krafy and sulphite processes use stainless steel to prevent corrosion in caustic or chlorides Stress corrosion cracking.

The bleach plants have utilized SS 316 to austenitic grade containing molybdenum in the problem areas.  High oil units are now using SS 904l instead SS 316.

Pulp mill bleach plants use austenitic stainless steels for their excellent corrosion resistance and weldability. Although, bleach plants are highly corrosive that over two decades they have closed washwater units and reduced effluent volumes. In advanced closed bleach plants, the traditional  steels are no longer fit for prolong service and several mills have recommended to use high alloy stainless steels, the nickel based alloys and titanium for greater corrosion resistance.

Super alloys are stronger and have good fatigue characteristics and they offer good corrosion resistance without the need of much maintenance. Although, the corrosion resistant alloys are expensive, there is also a challenge to select a suitable alloy with adequate resistance to prevent corrosion issues. The super Duplex stainless steel 2205 offer great corrosion resistance with prevention of pitting and crevice corrosion. The nickel based super alloys are perfect for use in pulp and paper industry for their good strength, durability and outstanding corrosion resistant properties. Additionally they offer prolong performance that make them ideal for service in the pulp and paper plants.