14/1, 21/0, 18/0, 18/8, 18/10, 301, 302, 304, and 316 are used to fabricate flatware and cookware. Different grades determine level of shine and prevention against corrosion.
Type 18 is old classification of stainless steel. American Iron and Steel Institute (AISI) developed 300 series designation, now used for all steel products. It gives a tighter control over the quality of stainless steel being used. Type 304 is the most common grade (the classic 18/8) used in fabricating cookware and flatware. Type 316 is the second most popular grade, the classic 18/10. Type 316 is better than 18/10 against corrosion.
Type 440 is used to make cutlery knives
Role of Carbon
Carbon is needed in iron to make iron into steel. Carbon up to 0.65% makes steel harden-able. Durability can be increased by adding up to 1.5% Carbon. Beyond 1.5%, the Carbon reduces the toughness and makes it brittle,
Role of Chromium
Chromium increases hardness penetration, toughness, and wear resistance. The most important effect on steel is to resist staining and corrosion. When the steel contains 10.5% or more Chromium, the surface reacts to the oxygen in the air forming Chromium oxide. Chromium oxide prevents the 'staining' (rusting) of the iron alloy, leading to the name stainless steel. If you scratch the surface, the oxygen in the air forms new chromium oxide surface. Higher the amount of Chromium, thicker is the protective surface and coated quicker by Chromium oxide after it has been scratched and exposed to air.
Role of Nickel
The stainless steel may corrode due to acids and salts. Nickel is added to prevent the corrosion and pitting. It hardens the steel, and adds whiteness to render polishing (shiny) characteristics. Higher the amount of Nickel, harder and shinier is the stainless steel, as well as the price.
Grades of Stainless steel Flatware and Cookware
- Economy grade Kitchenware in India is made with low carbon 14/1 (Chromium: 14%, Nickel: 1%) stainless steel
- Economy grade 21/0 is used to make economy flatware. It is comparable to classic 18/0. Neither 21/0, nor 18/0 has any Nickel.
- There are three classic standard grades of stainless steel sold in United States:
18/0: Chromium: 18%, No Nickel.
18/8: Chromium: 18%, Nickel: 8%. This is the most common stainless steel used worldwide
18/10: Chromium: 18%, Nickel: 10%. This is the most common 'high quality' grade
- The 300 series is modern standard with a slightly tighter margins. Type 304 is the most common stainless steel used in the world similar to classic 18/8 stainless steel. Therefore, other stainless steel are compared against Type 304
Type 304: Carbon: 0.08% max, Chromium:18% to 20% , Nickel: 8% to 10.5%
304 is the most common stainless steel produced, similar to classic 18/8 stainless steel. It is durable, resists most of the chemicals and withstands ordinary corrosion. Slightly magnetic.
304L is low carbon (0.03% max) version of 304 stainless steel.
Type 316: Carbon: 0.08% max, Chromium: 16% to 18%, Nickel: 0% to 14%, Molybdenum: 2% to 3%
Molybdenum gives greater resistance to various forms of deterioration caused by Chlorides such as seawater over 304. This is non-magnetic. This is the second most commonly used stainless steel similar to 18/10 with the addition of Molybdenum.
316L is the low carbon (0.03% max) version of 316. 316L is commonly used in commercial food processing equipment.
302: Carbon: 0.15% max, Chromium: 17% to19% , Nickel: 8% to 10%
This is same as 304 for corrosion resistance. It has higher strength than 304 due to additional carbon
301: Carbon: 0.15% max, Chromium: 16% to 18%, Nickel: 6% to 8%
Type 440 Cutlery Knife steel
This is used to fabricate cutlery knives such as chef's knife or paring knife, daggers (Chhuri,or Kirpan), and swords. It contains 12% to 14% Chromium sufficient enough to make it corrosion resistant. Corrosion resistance is achieved when it is hardened and surface ground and polished. It has better corrosion resistance, and tougher than 304. Higher amount of carbon provides better edge retention when properly heat-treated. 440A has the lowest amount of carbon, 440 B average amount of carbon, and 440 C is high carbon. Low carbon stainless steel knives (440A) are hard to sharpen at home, however they are most strain-resistant. High carbon stainless steel (440C) knives are the strongest and can be sharpened at home.
More expensive high carbon knives may contain Molybdenum (for increased corrosion resistance), and Vanadium for increased hardness.
Is one grade heavier than the other grade?
Chromium Nickel and Iron are basically same weight density. The weight for the same geometry is same for all the grades of the Stainless steel. Physically larger pieces are heavier than the smaller pieces. Choose flatware or cookware that feels heavier.
All 18/10 stainless steel is not same
Unfortunately, the federal laws permit labeling of stainless steel as 18/10, as long as the Nickel is at least 8.3%. Comparing it with 18/8, there is not much of a difference. You have to really compare the two products side by side and compare. Type 304 and Type 316 have better Nickel content. Stick with brand names
Stainless Steel Flatware
14/1, 21/0,18/0, 18/8, 18/10, 301, 302, 304,316, 316L are all acceptable.
Economy flatware is fabricated from 18/0, 21/0, and 14/1 stainless steel. New flatware is polished and shiny. After a while, the polish wears off and the flatware starts to look dull. The flatware is magnetic, makes it useful at restaurants that use magnetic rings to automatically pick flatware up from the trays when they are being emptied in to garbage.
Good quality flatware is fabricated from 18/8, 301, 302, and 304 stainless steel. It maintains its looks for a few years. These flatware is slightly magnetic.
Better quality flatware is fabricated from 18/10, 316, or 316L stainless steel. It is harder and shinier than Type 304, and maintains its eye appeal longest. This flatware is not magnetic. A very slight magnetism may be present depending on the manufacturing process.
Bowls and Storage Containers
You can use 14/1, 18/0, 21/0 for storing dry stuff such as Atta and sugar. You can also store milk or Dahi in the refrigerator.
Salt and acids corrode and pit low Nickel ware. Use 18/8, 18/10, 304, or 316 to store curries.
316L is suited for marinating (due to vinegar salt and lime juice) meats.
316, and 316 L are good to store Indian pickles for their high salt and acid content.
Cookware
Stainless steel is a poor conductor of heat. To remedy, this a layer of aluminum is sandwiched in between two layers of stainless steel to form the bottom. Normally, this cookware is called heavy bottom. Sometimes the external surface may be clad with copper.
Salt and acid (tomatoes, tamarind, Amchoor, lime juice) will corrode and pit stainless steel. 18/10, 316, and 316 L are the only good stainless steel to fabricate cookware for curries.
Always use 18/10, or 316 Heavy bottom stainless steel Pressure cookers, frying and sauté pans.
Commercial food processing equipment is generally made of Type 316L.
18/8 cookware is acceptable where no acids and salts are used, examples: boil milk, make Khoya (reduce milk), make Kheer (Rice pudding), make Gajar Halwa.
Stainless Steel Care
-Do not store or use stainless steel kitchenware along with regular steel (No Chromium) or cast iron kitchenware. Doing so will results in surface-rust to develop on stainless steel kitchenware.
- Use stainless steel pads or wool to scrub stainless steel pots
- Use wooden utensils with cast iron pots and pans.
ไม่มีความคิดเห็น:
แสดงความคิดเห็น