A Study of Stainless Steel and Its Use in Sugar Industry
Prepared by: Sunil B. Wesley
Definition: Stainless steel is essentially a low carbon steel which contains chromium at 10% or
more by weight. It is this addition of chromium that gives the steel its unique stainless, corrosionresisting properties.
Why is Stainless Steel Stainless? The chromium content of the steel allows the formation of a rough, adherent, invisible, corrosion-resisting chromium oxide film on the steel surface.
If damaged mechanically or chemically, this film is self-h ealin g, providing that oxygen, even in very small amounts, is present. The corrosion resistance and other useful properties of the steel are enhanced by increased chromium content and the addition of other elements such as molybdenum, nickel, and nitrogen.
Families of Stainless Steel
There are five families of stainless steel: \u2022 Ferritic, \u2022 Martensitic, \u2022 Austenitic, \u2022 Duplex,
And
\u2022 Precipitation
Hardening.
These names are derived from the crystal structure of the steels, which determines their metallurgical behaviour. Ferritic Ferritic stainless steels are plain chromium stainless steels with a chromium content varying between 12% and 18% and a low carbon content. They are magnetic and not hardenable by heat treatment. Martensitic Martensitic stainless steels were the first stainless steels that were commercially developed (as cutlery) and have a relatively high carbon content (0.1% - 1.2%) compared to other stainless steels. They are plain chromium steels containing between 12% and 18% chromium. Alloy 410 is the basic, general purpose, and magnetic grade that is hardenable by quenching and tempering. These stainless steels can be heat treated to obtain high strength with good ductility. Austenitic
The austenitic stainless steels contain between 16 - 25 percent chromium and sufficient nickel, manganese and nitrogen to keep them austenitic even at room temperatures. They have a FCC crystal structure, are non-magnetic, they have good toughness, they are generally considered spot weldable and the strength in these steels is obtained by solid solution strengthening and/or cold work. Austenitic stainless steels are used in many applications and may be the most widely used of all the stainless steels. Fire extinguishers, pots and pans, fixtures, virtually anywhere where bright and corrosion resistant parts are used. Duplex Duplex stainless steel plate contains relatively high levels of chromium (between 18% and 28%) and low to moderate amounts of nickel (between 1.5% and 8%). The high corrosion resistance and excellent mechanical properties of duplex stainless steels can be attributed to their chemical composition and balanced (duplex) microstructure of approximately equal volume percentages of ferrite and austenite.
LDX 2101\u00ae is a low nickel, nitrogen-enhanced lean duplex stainless steel with corrosion resistance similar to 304 but with much higher mechanical strength. This enables it to be used in thinner crosssections which provide cost savings to the end user. Alloys 2304 and 2205 are the most common grades. They both exhibit outstanding resistance to chloride stress-corrosion cracking.
\u201cSuper\u201d duplex grades have enhanced pitting and crevice corrosion resistance when compared with 300-series austenitic stainless steels or conventional duplex alloys. This can be attributed to the enhanced levels of chromium, molybdenum and nitrogen found in these materials. Alloy 2507 is the most common \u201csuper\u201d duplex grade. Precipitation Hardening Precipitation hardening stainless steels, like the martensitic types, can be strengthened (i.e., hardened) by heat treatment. The mechanism is metallurgically different from the process in the martensitic types. This means that either martensitic or austenitic precipitation hardening structures can be produced. These stainless steels combine high strength and hardness with corrosion resistance which is superior to that of the martensitic chromium stainless steels General Properties of Stainless Steels
Electrical Resistivity Surface & bulk resistance is higher than that for plain-carbon steels Thermal Conductivity About 40 to 50 percent that of plain-carbon steel Melting Temperature Plain-carbon:1480-1540 \u00b0C Martensitic: 1400-1530 \u00b0C Ferritic: 1400-1530 \u00b0C Austenitic: 1370-1450 \u00b0C Coefficient of Thermal Expansion Greater coefficient than plain-carbon steels High Strength Exhibit high strength at room and elevated temperatures Surface Preparation Surface films must be removed prior to welding Spot Spacing Less shunting is observed than plain-carbon steels
Figure: Typical Tensile Properties of Annealed Materials 300 Series Austenitic Type
302 304 304L 309 309S 310 310S 316 316L 317 317L 321 347
Tensile (MPa) min 517 517 482 517 517 517 517 517 482 517 517 517 517
Yield (MPa) min 207 207 207 207 207 207 207 207 172 207 207 207 207
Elongation min
40% 40% 40% 40% 40% 40% 40% 40% 35% 35% 35% 40% 40%
in in in in in in in in in in in in in
50mm 50mm 50mm 50mm 50mm 50mm 50mm 50mm 50mm 50mm 50mm 50mm 50mm
Hardness (Brinell) max
183 183 183 217 217 217 217 217 217 217 217 183 183
Hardness (Rockwell B) max 88 88 88 95 95 95 95 95 95 95 95 88 88
Effect Of Alloying Elements On Austenitic Stainless Steels Element
Carbon
Types of Grades of Steel All types
Chromium
All types
Nickel
All types
Nitrogen
XXXN
Niobium
347
Effects
Strongly promotes the formation of austenite. Can form a carbide with chromium that can lead to intergranular corrosion. Promotes formation of ferrite. Increases resistance to oxidation and corrosion. Promotes formation of austenite. Increases high-temperature strength, corrosion resistance, and ductility. Is a very strong austenite former. Like carbon, nitrogen is many times as effective as nickel in forming austenite. Increases strength, especially at cryogenic temperatures. Increases resistance to pitting corrosion. Added primarily to combine with carbon to reduce susceptibility to intergranular corrosion. Acts as a grain refiner. Promotes the formation of ferrite. Improves creep strength, but decreases creep
Manganese Molybdenum
2XX 316,317
Selenium of 303, 303Se Sulphur Silicon
230B
Titanium
321
Copper
CN-7M
ductility. Promotes the stability of austenite at or near room temperature but forms ferrite at high temperatures. Inhibits hot shortness by forming manganese sulphide. Improves strength at high temperatures. Improves corrosion resistance to reducing media. Promotes the formation of ferrite. Increases Machinability but promotes hot cracking during welding. Lowers corrosion resistance slightly. Increases weld penetration in gas tungsten arc welding. Increases resistance to scaling. Promotes formation of ferrite, and of sigma when greater than 1%. Small amounts are added to all grades for deoxidizing purposes. Increases fluidity including wetting of weld metal to base metal. Added primarily to combine with carbon to reduce susceptibility to intergranular corrosion. Acts as a grain refiner. Promotes the formation of ferrite. Improves creep strength. Generally added to stainless steel to increase corrosion resistance to certain environments. Decreases susceptibility to stresscorrosion cracking and provides age-hardening effects.
Markets by Grade
Stainless steel plate is a flat rolled product that is 10 inches (254 mm) and over in width, 0.1875 inches (4.76 mm) and over in thickness. There are several grades of steel in which plate is available. Use the guide below to find out which is right for you. Grade 303
Description Free machining, good mechanical corrosion resistant properties 304/304L/304H General Purpose
Applications and Mechanical and pharmaceutical components and parts
Chemical equipment, Pressure vessels, Cryogenic vessels, Dairy equipment, Nuclear vessels and components 316L Mo added to increase corrosion resistanceChemical processing equipment, Food processing equipment, Oil refining equipment, Paper industry digesters, evaporators & handling equipment 317L/317LMN More Mo and Cr added for better corrosion Chemical processing equipment, Dying equipment, Pulp and performance paper manufacturing equipment; Desalination equipment 321/321H Ti added to prevent carbicle precipitation Plate heat exchangers, Chemical equipment, Fire walls, Pressure tanks 347/347H Stabilized, excellent resistance to intergranular Radiant heaters, Aerospace components, Oil refining corrosion at elevated temperatures equipment 309S Cr and Ni increased for high temperature Annealing boxes, Chemical processing equipment (elevated temperature), Conveyor parts, Dryers 310S Same as 309, only more so Annealing boxes, Chemical processing equipment (elevated temperature), Conveyor parts, Dryers 410 General Purpose Press plates, Coal chutes, Oil burner parts Restricted carbon modification that prevents 410S Petroleum refining, petrochemical processing, ore processing, hardening and cracking when exposed to high thermal processing, gate valves, press plates temperatures or welding General purpose lean duplex possessing both Air pollution control, biofuels, chemical processing, food and LDX 2101 superior strength and corrosion resistance beverage processing, infrastructure, pulp and paper, comparable to 304L and 316L desalination and water and wastewater treatment 2304 Improved strength and stress corrosion Pulp & paper, Tanks, Digesters, Pharmaceutical, Food cracking compared to 304/316 industry 2205 High strength and superior corrosion Pressure vessels, Tanks, Piping, Scrubber systems, Digesters, resistance Heat exchangers 2507 Exceptional strength and corrosion resistance Oil and gas equipment, Heat exchangers, Chemical processing vessels, Desalination 17-4PH Capable of precipitation hardening Aerospace, Pulp and paper, Valves, Fittings, Food industry, Nuclear waste casks SSC-6MO 6% molybdenum superaustenitic alloy with Air pollution control, chemical processing, food and beverage outstanding resistance to chloride pitting,processing, ore processing, offshore oil and gas production, crevice corrosion and stress-corrosionpetroleum refining, pharmaceutical processing, power
cracking.
generation, pulp and paper, desalination
Specifications by Grade 303 A non-magnetic stainless steel specially designed for improved machinability. 304 Chromium-Nickel austenitic alloy used in a wide range of applications. 304L Chromium-Nickel austenitic alloy used in a wide range of applications. 316L Molybdenum bearing austenitic stainless steels which are more resistant to general corrosi pitting/crevice corrosion. 317L Molybdenum bearing austenitic stainless steels with increased resistance to chemical attack co to standard chromium-nickel austenitic stainless steels. 317LMN 317L + increased levels of moly and nitrogen for enhancing resistance to pitting and crevice cor 304H Modification of 304 in which the carbon content is controlled to a range of 0.04 – 0.10 to pr improved high temperature strength. 321/321H A stabilized stainless steel which has excellent resistance to intergranular corrosion follo exposure to temperatures in the chromium carbide precipitation range from 800 to 1500°F. 347/347H Stabilized stainless steel which offers excellent resistance to intergranular corrosion foll exposure to temperatures in the chromium precipitation range from 800 to 1500°F. 309/309S Austenitic stainless steel used in applications where elevated temperatures are present. 310S Austenitic stainless steel used in applications where elevated temperatures are present. 410 Hardenable, straight-chromium stainless steel which combines superior wear resistance with e corrosion resistance. 410S Low carbon non-hardening modification of 410. Resists cracking when exposed to high temper or in the as-welded condition. LDX 2101 Low nickel lean duplex stainless steel possessing both superior strength and chloride stress-co cracking resistance when compared to 300 series stainless steels. 2304 A high chromium-low nickel-moly free duplex stainless steel exhibiting improved strength and corrosion resistance properties compared to 304/316 austenitic stainless steels. 2205 A high chromium-nickel-moly duplex stainless steel providing high strength and superior resista general, local, and stress corrosion compared to 316L or 317L. 2507 A chromium-nickel-moly super duplex stainless steel with exceptional strength and corro resistance in the chemical process, petrochemical, and seawater environments. 17-4PH Martensitic stainless steel that is capable of precipitation hardening. This stainless steel has ve strength and hardness. SSC-6MO Superaustenitic 6% molybdenum alloy that exhibits superior resistance to chloride pitting, crevice corrosion and stress-corrosion cracking when compared with the standard 300 series and duplex stainless steels. Premier corrosion resistant austenitic stainless steel. Types of Corrosion found in Stainless Steel
The corrosion resistance of stainless steel is dependent on a thin invisible film on the steel surface, the passive film. There are, however, environments that cause permanent breakdown of the passive layer. Under circumstances where the passive layer cannot be rebuilt, corrosion occurs on the unprotected surface. Different media can cause different types of corrosion attack that may vary in nature and appearance. Several forms of corrosion can occur on stainless steels plates. Uniform Corrosion
In this case, the passive layer on a stainless steel surface breaks down partly or completely. The corrosion then propagates at a rate determined by a combination of the corrosive environment and the alloy composition. Uniform corrosion or general corrosion occurs on stainless steel in acid environments or hot alkaline solutions. Severe environments from a corrosive point of view are high concentrations of hydrochloric or hydrofluoric acid in which the corrosion may propagate at a rate that can be detrimental to a construction. Pitting Corrosion
Pitting is a form of localized corrosion and is characterized by attacks at small discrete spots on the steel surface. Pitting occurs mainly in the presence of neutral or acidic solutions containing chlorides or
other halides. Chloride ions facilitate a local breakdown of the passive layer, especially if there are imperfections in the metal surface. Crevice Corrosion
Crevice corrosion is a form of localized corrosion and occurs under the same conditions as pitting, i.e., in neutral or acidic chloride solutions. However, attack starts more easily in a narrow crevice than on an unshielded surface. Crevices, such as those found at flange joints or at threaded connections, are thus often the most critical sites for corrosion. Stress Corrosion Cracking
A material failure may be accelerated by the combined effect of corrosion and mechanical stress. Two examples of such processes are stress corrosion cracking and corrosion fatigue. The most common type is transgranular stress corrosion cracking, SCC, which may develop in concentrated chloride-containing environments. Previously, it was generally considered that an elevated temperature was necessary for SCC to occur. In recent years, however, SCC has been experienced at ambient temperature on standard grade steels like 304L or 316L that were exposed to high tensile stresses. In these cases the steel surface was contaminated with solid salt deposits and the humidity of the atmosphere was rather high. These two factors resulted in a thin liquid film saturated with chloride. Other contaminants, such as H2S, may increase the risk of SCC in chloride-containing environments. Other environments that may give rise to SCC, particularly on low alloy steels, include very alkaline solutions at high temperatures. A typical SCC attack takes the form of thin, branched cracks. Galvanic Corrosion
When two different metals are immersed in a corrosive solution, each will develop a corrosion potential. If the corrosion potential of the two metals is significantly different, and they are in direct contact and immersed in an electrolyte, the more noble metal will become the cathode and the more active metal will become the anode. A measurable current may flow between the anode and the cathode. The corrosion rate of the anode will be increased and the cathode decreased. The increased corrosion of the anode is called "galvanic corrosion." Intergranular Corrosion This type of corrosion may occur if the area around the grain boundaries is less corrosion resistant than the matrix in the medium in question. A classical case is when chromium carbide is precipitated at the grain boundaries. The adjacent matrix will be depleted in chromium, and a narrow region around the grain boundary may, therefore, be less corrosion resistant than the rest of the material. Corrosion Fatigue
It is well known that a material subjected to a cyclic load far below the ultimate tensile stress can fail, a process called fatigue. If the metal is simultaneously exposed to a corrosive environment, the failure can take place at even lower loads and after a shorter time. Contrary to a pure mechanical fatigue, there is no fatigue limit load in corrosion-assisted fatigue. Atmospheric Corrosion
In architectural applications, such as wall claddings and decorations, stainless steel is often chosen due to its aesthetic qualities and the fact that it can be supplied in a variety of surfaces. Selection of specific stainless steel grades is based on experience and knowledge of the performance of specific grades with regard to the environment. Atmospheric environments are most commonly divided into four categories: rural, urban, industrial, and marine. The environments vary depending on the severity from a corrosive point of view. The importance of keeping the surface clean by regular washing to avoid staining and dust cannot be stressed enough.
Fig: General Process Flow for Manufacturing of Sugar from Sugarcane Material Currently Used • Mild steel • Brass
Corrosion is widely recognized as a major problem in the sugar industry. The Indian sugar industry has woken up to this problem and is now contemplating measures to address it. Rough estimates indicated that the losses due to corrosion in the Indian sugar industry amount to over Rs 10 billion1 (US$ 250 million). Types of Corrosion Atmospheric Corrosion Galvanic corrosion Pitting corrosion Crevice Corrosion Stress corrosion High temperature corrosion Corrosion erosion Corrosion in Sugar Industry Most of the equipment is made in Sugar industry from Mild steel. This has resulted in the corrosion becoming a major factor to be addressed in the Sugar industry. Colour in sugar due to Iron Oxide: In India, plantation white sugar is manufactured, where, generally no further refining is carried out. Therefore it is important to minimize color imparting impurities (corrosion) in the process equipment. It is estimated that about 20-25 kg equivalent of Fe2O3 is mixed in the juice for every 1000 tones of Cane processed through sulphitation process. (Source: P Honig, Principles of Sugar Technology Part-I). Due to this corrosion, the color of juice darkens resulting in loss of whiteness. Continuous Working : As the sugar industry is working continuosly during the season, the breakdown cost is very high (of the order of Rs 4-10 lacs/ hour depending upon the size of plant). This makes the breakdowns unaffordable and in many processes, the standby equipments are provided resulting in higher capital cost. Off Season Maintenance: One of the major reason of corrosion is the atmospheric oxidation of mild steel equipment during the off-season due to exposure to hot and humid conditions after the process is
shut down. During restarting, most of this rust is transferred to Sugar which needs re-melting to reduce wastage. Perishable Raw Material: The sugarcane is a perishable material and deterioration starts soon after harvesting. Therefore it becomes important that the sugarcane is processed as fast as possible (generally target is – 72 hrs after harvesting). Any breakdown in the equipment leads to a fall in recovery from the sugarcane, extra colour formation and the loss of sugar from the in-process material. Besides this, there is a problem of managing the huge stock of sugarcane-laden wagons which may create law and order issues. Hygiene: The tanks and equipment fabricated from the mild steel is not conducive to hygiene and the resultant sugar made from processes commands lower realization in the competitive market. Due to these reasons, tackling the issue of corrosion has become a major challenge the world over. Most plants across the world have switched over to various grades of Stainless Steel. In India also, the plants engaged in manufacture of refined sugar have started shifting to the use of stainless steel in various equipment. Medium Analysis of Cane sugar Manufacturing Station & Corrosion rates encountered in mild steel and brass5
S.No.
Station/medium
pH
Temperature oC
1 2 3 4 5 6 7
Condenser water Mixed (raw) juice Sulphitated juice Classified juice Filtered juice Sulphitated juice Final molasses
6.8 5.5 7.1 6.9 6.5 5.1 5.7
41 29 64 98 76 46 45
Av.Corrosion rate in MS (mdd) 401.91 942.33 213.18 655.50 734.89 405.18 100.65
Corrosion rate in brass(mdd) 26.75 53.54 24.30 38.79 67.06 84.75 22.95
Advantages of Stainless Steel over Mild Steel 1. Low / Negligible corrosion : The Chromium oxide passive layer formed is resistant to most types of corrosive media (depending upon the grade used). Besides this, the layer is self healing in that any damage to this layer is self repaired in the presence of Oxygen in the atmosphere. 2. Strength: Stainless steel is stronger than mild steel. As a result, in most cases it is possible to reduce the plate thickness by 20 - 30% without compromising on the structural strength. Also it offers better abrasion resistance than mild steel and hence it offers much higher life. 3. Low corrosion allowance: The average life expectancy of Stainless steel is 6 to 10 times that of Mild steel. Since the material is resistant to most media, there is no need to provide for corrosion allowances. This further brings down the equipment weight. 4. Low maintenance: Since in Stainless steel, no coatings/ protective painting is required, therefore, this recurring expenses are avoided 5. Superior hygiene: Stainless Steels are the recommended material for hygiene related equipment like food processing, pharmaceutical, etc. 6. Better heat transfer: Stainless Steel offers equivalent / better heat transfer than other material like brass etc. Also, since it has much less problem of scaling, there is little deterioration between the scheduled cleanings. Also, wear loss due to cleaning using cutter for descaling of brass tubes is reduced appreciably. 7. Lower operating cost: Use of stainless steel can bring down the breakdown incidence appreciably resulting in lowering the cost of operations. 8. Lifecycle cost: It is established that the Stainless steel offers lower lifecycle cost as compared to mild steel. It is found that the savings by replacing mild steel with Stainless steel can result in 30-100% savings over the lifetime of the equipment. 9. Safety: Not the least, stainless steel enhances safety throughout the plant due to reduction in accidents/ leakages.
Recommended equipment for substitution with stainless steels Listed below are the range of equipments which will benefit from the use of appropriate grade of stainless steel. The recommended grades as well as the life cycle cost comparison with the existing material are mentioned later. The estimated savings in annual replacement material costs due to upgrading with appropriate stainless steel grade can go upto even 50%. • • • • • • • • • • • • • • • • • • • • • • •
Cane carrier side plates Cane carrier chain links Rake type inter carrier, Wear Pads troughs and rakes Mill imbibition piping Donnely chutes Juice pump body and impellers (up to sulphited juice pump) Mill juice gutters Whirler tanks, screened juice and unscreened juice tanks Bagasse carrier trough Raw juice lines Clarifier mud scrapers Juice sulphiter SO2 gas pipeline Rotary vacuum filter filtrate lines and tanks Juice heater covers Juice heater condensate lines Vacuum crystallizer top dome Pan and last evaporator vapor lines Condensate lines for evaporator Molasses gutters Partition plates inside continuous centrifugals Centrifugal basket ribs Hopper trough and base plates
Criteria for selection of suitable stainless steel for sugar industry Typical properties which go into the selection of material are: • Mechanical / chemical properties (imparting features such as strength) • Fabricability and weldability • Corrosion performance • Wear performance Besides the above factors, cost of using a particular grade is also a concern.
The essential properties that are looked for are:
a) Corrosion and erosion resistance b) Abrasion resistance – Particularly resistant to wet abrasion c) High strength and light weight d) Good fabricability • Welding • Bending • Cutting & Shearing • Forming e) Good white colouration f) Availability at affordable cost The type 304 fulfils all the above attributes except that it is an expensive material and its price is extremely sensitive to the rise or fall in international nickel price. Type 409 is largely used in handling dry or semidry products mainly to exercise cost economy. However many users face difficulties in fabrication of 409 and use type 304 in non critical areas adding cost to the project.
With a twin objective of exercising cost economy in building up of new sugar plants and ensuring an uninterrupted indigenous supply source, Jindal Stainless Ltd. Has conducted extensive lab studies on some Chrome-Manganese austenitic stainless steel grades as possible substitute to type 304 or 409L as the case may be.
Replacing Brass Tubes with Stainless Steel Tubes
The world over most sugar mills have switched over to Stainless steel tubes. This is happening at a fast rate in India also. It is calculated that just by replacing the brass tubes with SS tubes (204Cu), a 5000 TCD plant can save up to Rs 3 Crores in the initial investment and additional up to Rs 1 Crore in recurring maintenance cost annually. The details of the comparison are provided below.
Comparison of Brass vs Stainless steel Tube Factor Strength Heat Transfer Scaling Cleaning Initial cost Scrap value Total life
Brass Stainless Steel Higher thickness-1.6/2 mmLow thickness -1.2mm Good Good High Low High frequency Less frequent High 40% of Brass Upto 75% Upto 50% 2-4 season 10-12 seasons
This guide suggests the Stainless Steel grades keeping in view the optimum performance to cost ratio. S No Equipment
1
2
4
5
6
Working Environment
Existing Material
Suggeste d Material
AbrasionCorrosion
MS
J4
Longer life
Rake elevators, side Corrosion plates, base plate
MS
J4
Longer life/Hygiene
Juice Trays/Gutters Corrosion
MS, Al, Cu lined
J4 204Cu
Trough & Screw Conveyors
Abrasion, Corrosion
MS
JSL AUS
Hygiene/ longer life/ lower cost Longer Life
Lining below Corrosion Milling Head Stock
MS
JSL AUS
-do-
Lining below Corrosion Milling bearing base
MS
J4
-do-
Bagasse carrier and Corrosion Conveyor Sulphur Station SO2 corrosion, High Juice Tanks/pipe temperature Lines
MS
Cane Conveyor : Side plates, Chain links, pin, bushes & rollers Milling : Donnelly chutes
Abrasion, Mild Steel J4 slidability, wear, corrosion
Juice sulphitation Juice/ syrup Tanks Corrosion
Juice Heaters, Evaporator, Pans
Corrosion
MS/ cast iron
Increase in life, reduction in b/down
-do204Cu
MS (8mm) J4
MS
Benefit
204Cu
Longer life
Avoid Discoloration due to corrosion No color From Fe2O3, reduced weight, longer life of SS tubes due to no galvanic
corrosion Reduced cost Savings of approx Rs 3cr ininitial investment and Rs 40-50 lacs in Recurring maintenance for a 5000 TCD plant Longer life
7
Tubes – Juice Corrosion, Heater, Evaporator, SO2 gas in Pans juice heater tubes, high temp, scaling
Brass
204Cu
8
Saveall, Vapor line, Corrosion due Condensers, to – Acidic Tailpipes vapor, water vapor, High velocity Pipelines Heavy corrosion
MS
204Cu
MS
JSL Tube
Abrasion, sugar looses lusture Corrosion, Crystallizers and Iron Centrifugals contamination Whirling tank Raw Corrosion juice Tanks Molasses tank/ cover Unsulphured syrup Sulphured syrup tank
MS/ Spring steel MS/ SS
J4 204Cu
No iron contamination
MS
204Cu
13
Juice Pumps
Corrosion
MS/ Cast iron
204Cu
14
Vacuum filters
Corrosion
MS body with SS screens
204Cu
Corrosion resistance and no discoloration, reduced painting Corrosion resistance/ low b/down Corrosion resistance
9
10 11 12
Hoppers
Longer life and safety due to no leakage Wear resistance
References 1. V. Bhardwaj, J.C. Patil, L.K. Singhal, Pravin Goel (2007) Role of SS material to combat corrosion in sugar industry – A study under R&D initiative of STAI., Proceedings of Seminar at Gangtok Sikkim. 2. R.K. Goyal et al (2006), Stainless steel in sugar industry – A lifecycle perspective, Proceedings, Annual conference STAI. 3. S.K. Gupta, et al, (2007) National Sugar Institute, Kanpur, All India Seminar on Role of stainless steel to combat corrosion in sugar industry,
4. R.K.Goyal, Rajesh Khosla, and Pravin Goel (2006) Stainless steel in sugar industry – A lifecycle perspective, Proceedings of the 67th Annual Convention of STAI. 5. D Kamila, L.N. Dash, L.K. Singhal (2006) Use of chrome manganese austenitic stainless steel in sugar industry – A conceptual approach. Proceedings of the 67th Annual Convention of STAI. 6. http://www.assda.asn.au/ 7. http://www.sandmeyersteel.com/ 8. www.stainless-uk.co.uk 9. www.stainless-steel-world.nt 10. www.stainlesssteel.org 11. www.arcelor-stainless.com 12. www.t at a.com
