Stainless steel
From CollabLandWiki
Manufacturing / extraction processes
The History of Stainless Steel:
1912 English metallurgist Harry Brearley invents stainless steel in his search for an alloy to protect cannon bores from erosion. The first commercial production of stainless steel occurs in August, 1913. 1915 During World War I, stainless steel is used to manufacture valves for aircraft engines. 1919-1923 Sheffield cutlers start regular production of stainless steel cutlery, surgical scalpels and tools. 1924 The first stainless steel roof makes an appearance in America. 1928 The brewery industry installs the first stainless steel fermenting tank. 1929 The first stainless steel tanker is used for transporting 3,000 gallons of milk. 1929-1930 The Chrysler Building’s top seven arches are clad in stainless steel. This New York City landmark is one of the world’s most recognized skyscrapers. 1931 The first stainless steel railway carriage appears in the US. Also, Rolls Royce produces the first stainless steel radiator grill and emblem. 1933 Stainless steel kitchen sinks and furniture are introduced. 1950 Stainless steel is used with increasing frequency for car accessories. 1954 The first stainless steel underwater TV camera is made. 1963 The first stainless steel razor blades are produced. 1969 The first men on the moon (Apollo 11) are taken there by a stainless steel Saturn V Rocket. 2000-Current Grey Feather Toy Creations introduces bird toys constructed exclusively with stainless steel.
Manufacturing process: Almost all stainless steel is melted in an Electric Arc Furnace(EAF)or Basic Oxygen Furnace(BOF),the chemistry is refined in the Argon Oxygen Decarburising process(AOD),and slabs made by Continuous Casting.These slabs may be partially or fully surface ground before being charged to a reheating furnace,then hot rolled to plate or coil.
Steps: Melting--Refining--Casting--Rolling
At least 30,000 tonnes of stainless steel scrap in Australia will be exported a year to stainless steel mills in countries including China, South Korea, Taiwan, India and Japan.
Consumption of stainless steel scrap - 2004 China — 2.8 million tonnes of production using 900,000 tonnes of scrap. Japan — 2.4 million tonnes of production capacity using 900,000 tonnes of scrap. South Korea — 2.3 million tonnes of production using 800,000 tonnes of scrap. Product mix 80% austenitic, 20% ferritic. Taiwan — 2.6 million tonnes of production using 600,000 tonnes of scrap. India — 1.4 million tonnes of production using 300,000 tonnes of scrap.
Extraction process: The process has three steps: 1. Addition of H and ectraction of HNO and HF with an origanic solution,containing 75% TBP in kerosene, in a pulsed column operation 2. Precipitation of the metals left in the aqueous raffinate 3. Stripping HNO and HF from the organic solution with water in a second pulsed column operation and recycling the acids back to the pickling bath
Material properties
Stainless steels have higher resistance to oxidation (rust) and corrosion in many natural and man made environments; however, it is important to select the correct type and grade of stainless steel for the particular application.They always look shiny and smooth.High oxidation resistance in air at ambient temperature is normally achieved with additions of more than 12% (by weight) chromium. The chromium forms a passivation layer of chromium(III) oxide (Cr2O3) when exposed to oxygen. The layer is too thin to be visible, meaning the metal stays shiny. It is, however, impervious to water and air, protecting the metal beneath. Also, when the surface is scratched this layer quickly reforms. This phenomenon is called passivation by materials scientists, and is seen in other metals, such as aluminium. When stainless steel parts such as nuts and bolts are forced together, the oxide layer can be scraped off causing the parts to weld together. When disassembled, the welded material may be torn and pitted, an effect that is known as galling.
Format & finish of materials
Stainless steel is commonly used in kitchens, boats and as handrails. In kitchens utensils, benches and sinks are the most common stainless steel products. Stainless steel is usually folded, bent, cut, welded and formed. This allows stainless steel to be made into a lot of things we use in our daily lives. Stainless steel has a unique surface quality as it has no pores or cracks that allow dirt or bacteria to attach to the surface, allowing easy cleaning and a practical way to prepare food on. This is also the main reason why we produce stainless steel handrails, as handrails are used daily and hold bacterial from every user. Stainless steel comes in a wide range of finishes ranging from dull 2D finish to the 2B mill finish, which is most used in architectural applications.
The surface finish is quite important when deciding what finish is best suited for the application. The surface finish will determine how people use or misuse the product. For example having a handrail that is a mirror finish will result in a very slippery handrail. On the other hand the finer the finish is the less likely it is to corrode.
Stainless steel has many types of mill finishes the common finishes are:
1. Frosty white. The finish was created by hot rolling, annealing and descaling. Mostly used for industrial use.
2D. Dull cold rolled finish. The finish was created by cold rolling, annealing and descaling. Mostly used for industrial use.
2B. Bright, dense. The finish was created like 2B but is lightly polished. Used in producing industrial equipment and architectural applications.
3. Bright. A polished finish using a 100 mesh abrasive. This type of finish is not normally used.
4. Bright. It is finished with 120 to 150 mesh abrasives. This finish is commonly used in restaurants and sanitary equipment.
7. High reflectivity. Produced by polishing finely. For decorative use.
8. Mirror finish. Acquired by polishing and buffing over a long period of time. The surface is free of any lines. For decorative use.
Video link below that shows the process of buffing and refining the welded pieces of stainless steel to obtain a mirror finish.
http://video.yahoo.com/video/play?vid=f9e79ae2ce0b15b12dbbcfd2d90f2530.611524
Common fixing methods
The most common way to fix stainless steel is to weld it.Other methods include gluing,bolting or riveting.Welding stainless steel together followed by sanding and polishing the material to obtain a smooth jointless finish.The gluing method is commonly used when fitting a stainless steel bench top to a bench.Bolting and riveting is a quick method of fixing stainless steel to other material or to itself.In addition,stainless steel usually joined by GTAW(Gas tungsten arc welding).An automated GTAW process called orbital welding is gaining popularity.It requires less operator hand skill and produces a printed record of the welding parameters.Because tubing has thin walls,autogenous butt welds are used.No filler material is added to the joint,as sections are merely fused together.PAW is also used sometimes.After welding,a second machine folds the standing joint in a simple fold just above the weld line.This strengthens the joint and helps to straighten the seam.
Durability and maintenance requirements
Stainless steel is a very durable material used outdoors and indoors. Stainless steel usually last a lifetime only worn down with scratches. It is usually thrown out when other parts of the stainless steel product fails, for example a pot handle on stainless steel pot breaks and the whole pot is thrown out . Because stainless steel has such a low corrosion rate, the material is used in areas where it is exposed to water and heavy duty use. Maintenance on stainless steel is very low, only needing a wipe or clean every so often. When stainless steel is exposed to sea water it is best to regularly rinse with water stopping it from slowly corroding.
Some grades of stainless steel can resist very high temperatures while still keeping its strength and size, these are the higher grades of stainless steel. The type of mill finish also has an impact on the durability and maintenance of the stainless steel product. For example a mirror finish has a lower corrosion rate than a matt finish.
The stainless steel surface that is stainless is made up of chromium rich oxide film. This layer of film is very thin only a few atoms thick. When the film is damaged through scratching the raw material self repairs when exposed to oxygen, the layer of film flooding the damaged area making it stainless again. This repairing method is known as the rapid self repairing quality of chromium rich film.
Life-cycle / recycling possibilities
Stainless steel is 100% recyclable this means Stainless Steel is constantly recycled. Stainless steel today is made up of around 60% recycled stainless steel. 25% old scrap stainless steel, 35% industrial scrap stainless steel and 40% new raw material.
The 25% old scrap stainless steel includes stainless steel products that no longer function, for example cars, fridges and washing machines. The 35% industrial scrap is made up of new scrap which include off cuts and industrial fabricated products. 40% is made up of new raw material, which isn’t recycled. This means a combination of three ages of stainless steel produce new stainless steel, allowing a mix of old and new stainless steel to be used. Allow products we no longer use to be recycled and returned to us in a new stainless steel form.
When recycling materials there is a risk of degradation. Stainless steel keeps its basic properties when recycled unlike other industrial materials. This means stainless steel maintains its stainless property for its whole life time.
List of manufacturers / contractors / suppliers
Stainless Steel Projects
Address: Vinegar Hill Rd Kamo Whangarei Phone number: 0-9-435 2466 Listed in Stainless Steel Engineers - General
Brothers Stainless Steel Limited
Address: Unit 3 65 Pharazyn St Lower Hutt Wellington Phone number: 0-4-568 3750 Listed in Stainless Steel
Sculpture In Stainless Steel
Address: Great Barrier Island Auckland Phone number: 0-9-429 0080 Listed in Garden Ornaments
Classic Stainless Steel Ltd
Address: 25 Kaka St Otahuhu Auckland Phone number: 0-9-276 7648 Listed in Bench Tops Stainless Steel
P.E.C Stainless Steel
Address: 9&10/518 Buckland Rd Pukekohe Auckland Phone number: 0-9-239 2981 Listed in Steel Processing
Stainless Steel And Aluminium Welding Academy
Address: Unit 7 91-97 Shakespeare Rd Waltham Christchurch Phone number: 0-3-365 8895 Listed in Training Services Educational Services
Stainless Steel Concepts & Design Ltd
Address: 6 Brick St Henderson Auckland Phone number: 0-9-835 4808 Listed in Engineers - Sheet Metal
Mackesy Stainless Steel Ltd
Address: 28 Greenmount Dve East Tamaki Auckland Phone number: 0-9-274 9230 Listed in Stainless Steel
AEA Stainless Steel
Address: 111 A Tasman St Opunake Phone number: 0-6-761 8834 Listed in Stainless Steel Engineers - General Water Heaters
Stainless Steel HandrailsBalustrades Handrails Pool Fence Stainless Steel Marine-Boats Aluminium Stair Rails
Address: 22 Gabador Pl Mt Wellington Auckland Phone number: 0-9-573 0239 Listed in Staircases & Handrails
Lifetime Stainless Steel (1990) Ltd
Address: 192 Station Rd Penrose Auckland Phone number: 0-9-580 0206 Listed in Stainless Steel
Add Vance Stainless Steel & Pump Services Limited
Address: 19 Commerce St Putaruru Phone number: 0-7-883 8067 Listed in Water Pumps Pumping Equipment
P E C Stainless Steel
Address: 72 Pioneer Rd Pokeno Franklin Phone number: 0-9-233 6815 Listed in Stainless Steel
Professional Stainless Steel Kitchen Equipment Ltd
Address: 43 Station Rd Penrose Auckland Phone number: 0-9-580 2381 Listed in Kitchen Fittings & Design
ASP - All Stainless Steel Projects
Address: Kairanga Bunnythorpe Rd RD5 Palmerston North Phone number: 0-6-357 7784 Listed in Stainless Steel
Stainless Steel Fasteners Ltd
Address: 269 A Mt Smart Rd Penrose Auckland Phone number: 0-9-525 6004 Listed in Fasteners - Industrial
Kum Fu Stainless Steel Kitchen Equipment Ltd
Address: 2/9 Andromeda Cre East Tamaki Auckland Phone number: 0-9-274 8108 Listed in Gas Equipment
Dixon Marine Products & Stainless Steel Manufacture
Address: Wilson Rd Warkworth Phone number: 0-9-425 8831 Listed in Stainless Steel
Product information / specifications
What is stainless steel?
Stainless steel is the common name for metal alloys consisting of greater than 50% Iron (Fe) and greater than 10.5% Chromium (Cr). Stainless steel is made up of chromium, carbon steel, iron, nickel, niobium, molybdenum, and titanium giving it stain resistance properties. At least 12% chromium is needed to give the property of stainless. Also additional nickel, niobium, molybdenum, and titanium improves the total corrosion resistance of stainless steel.
Stainless steel is produced in three main categories, these are:
Austenitic stainless steel: Is a chromium nickel iron alloy made up of 16-26% chromium, 6-22% nickel, with low carbon content, this type of stainless steel is not magnetic. The amount of nickel allows an increase of corrosion resistance. Type 304, a type of austenitic stainless steel has 18% chromium and 8% nickel. Type 304 is the most commonly used type of stainless steel as it is cheap and has a medium corrosion resistance. Type 316 is a marine type which is used in exterior fittings around boats. Type 316 has a higher corrosion resistance than type 304 which is suited for outdoor areas, Type 316 is more expensive due to the manufacturing costs of producing this type of stainless steel.
Martensitic stainless steel: Is a chromium iron alloy with 10.5-17% chromium, is magnetic, it is hard to weld and form and it can be tempered and hardened. Cutlery is commonly produced out of this type of stainless steel. The hardness of martensitic stainless steel depends on its amount of carbon, the more carbon it has the stronger it is. In spite of this the higher the carbon content the more vulnerable it is to corrosion.
Ferritic stainless steel: Is a chromium iron alloy with 17-27% chromium, does not have good weldability properties, has low amounts of carbon and is magnetic. Cooking utensils are usually produced out of this type of stainless steel.
Visiting Stainless steel LTD
Journey into the harsh life of stainless steel manufacturing.
Bright works stainless limited and GSL general sheet metals Ltd. These are the two companies we visited to get an idea of how stainless steel is fabricated and general information regarding its properties and how we use stainless steel today.
Our journey to these companies began with a behind the scenes tour of how stainless steel is processed. We found out how stainless steel was formatted, finished, where they get their stainless steel from, fixing methods, heavy stainless steel machinery and most importantly the process it goes through to become the final product.
Thanks to these kind companies we found out how stainless steel is used, not so much in Wellington but in New Zealand as a whole. As the process is exactly the same throughout New Zealand. The process being, most of the stainless steel coming from overseas (as it is cheaper) then fabricated into products that we use frequently use for example hand rails, bench tops, sinks and architectural building applications, then passed on to the supplier which then distributes to the consumer.
Our day out also showed us the work rate it takes to produce these products. Because stainless steel isn’t the softest material heavy machinery is used to cut, fold, bend, and mold this material as well as welding and long periods of polishing to eventually produce products we use. Our day out was also a chance to get to know the material, finding out information from the people that work with the material day in and day out, information that ten internet search engines couldn’t find out.
To sum up our main focus of our trip was to gain a deeper knowledge of stainless steel, information that helped us further our small knowledge of the stainless steel material.
Precedent 1: Robert Jahnkes stainless steel spinning top sculpture
Stainless steel spinning top sculpture
This stainless steel spinning top sculpture was created by Robert Jahnke in 2002. I selected this sculpture as my precedent because I believe this sculpture describes the properties of stainless steel and adds character to the busy pedestrian path. This sculpture shows off the reflectable, moldable, stainless and sleek finish properties of stainless steel.
My photos explore the different ways the surrounding elements interact with the sculpture. For example droplets of rain which sit on sculpture, the material not soaking up the water but allowing the droplets to slowly evaporate. Another example is the cities ambient glow which surrounds the sculpture gives the spinning top character, in addition because of the convex shaped sculpture the stainless steel morphs its surroundings twisting, modifying buildings and people that are in proximity.
Precedent 2:Public use around urban area
Handdrail and stainless steel landscape
I choose oriental bay, civic square for my precedent research walk, there is a formed stainless steel made handrail in the waterfront. Due to the most important property of stainless steel-higher resistance to oxidation (rust) and corrosion in many natural and man made environments. Stainless steel made handrails are used in wide range of public. Good looking(finish), easy to keep clean(smooth)and easy to install make stainless steel popular in modern construction.
Two big images show the stainless steel landscape design in Christchurch downtown.This loudspeaker like object is well fomed,always new look and has became a city sign which attracts many people.Although the Cathedral square is a heritage site,this sculpture enrichs the cityscape because it is a symbol of modern material made landscape.The last image shows another good public use example near the Wellington civic square.The most significant reason to use stainless steel outside is that it will never be corroded by air,wind or rain.
Precedent 3: stainless steel use in global landscape projects
References
NI & Euro Inox (1994) Design Manual for Structural Stainless Steel NiDI Ref. No. 11 013
ASSDA TRAINING NOTES(1999) THE SURFCAE FINISH ON STAINLESS STEELS. NO 4
An intro to stainless steel, J.Gordon Parr and Albert Hanson, 1966
http://www.ecm-espresso.com.au/giotto_detail_a1.htm
http://chemistry.about.com/cs/metalsandalloys/a/aa071201a.htm
http://www.greyfeathertoys.com/html/whystainless.html
http://www.hghouston.com/ssdata.html
http://chemistry.about.com/cs/metalsandalloys/a/aa071201a.htm
http://www.assda.asn.au/asp/index.asp?pgid=17956
http://www.azom.com/details.asp?ArticleID=965
http://www.fantes.com/stainless_steel.htm
http://www.azom.com/details.asp?ArticleID=1178
