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Introduction to the basic characteristics of the stainless steel

1. History

Stainless steel attached property experts name a British steel industries Harry Brearley. while in 1913, he invented the first steel line characteristic owns high abrasion resistance, by reducing the carbon content down into components for chromium steel (0.24% to 12.8% C and Cr).

After slow deployment of the German steel company Krupp steel continue to improve this by adding nickel to steel elements to improve corrosion resistance to acids and makes for easy machining softer. On the basis of this invention 2 that 2 pieces of steel grade 400 and 300 established just before World War First. After the war, the 20 years of the 20th century, a specialist British steel industries W. H Hatfield continued his research, strong ideas of stainless steel. By harmonizing the different ratio between nickel and chromium in the steel sectors, he has to build a brand new one the stainless steel 18/8 ko ratio 8% Ni and 18% Cr, is the steel grade 304 now familiar. He is also the inventor of the steel sample 321 by way of the addition of titanium to steel components ownership ratio above 18/8.

After nearly a century, the birth and growth, now stainless steel has been used diversity in all areas of civil and industrial with more than 100 different steel grades. In the field of metallurgy, stainless term ko steel (stainless steel) is used to refer to a form of iron alloys containing a minimum of 10.5% chromium. The name “Stainless Steel ko” but in fact it’s just the iron alloy or discoloration not corrode easily as the other ordinary steel samples. This raw material to be called corrosion-resistant steel. daily, with the popularity of different ways to apply stainless steel for different surfaces to increase the life of objects. In life, they appear everywhere as the blades cut or strap watches …


Stainless steel bearing resistance to oxidation and corrosion is very high, but the selection of the right type and parameters of our technologies to appropriate to each particular case is very crucial. Resistant to oxidation in the air around the surrounding normal temperature of stainless steel bearing was not due to the ratio of chromium to the alloy (as low as 13% and up to 26% of cases makes the environment makes harsh). the current state of the chromium is oxidised chromium oxide usually (III). chromium in the steel alloy when exposed to the air, a very thin layer of chromium oxide III appeared on the surface of the material; This thin layer that can not be seen with the naked eye, which means the metal surface is still shiny. besides, they just did not work and the air-owned security control should be below grade steel. This phenomenon is called oxidation engineered stainless material. to see this phenomenon for owning one of the other metals such as aluminum and zinc in.

while objects made of stainless steel were coordinated to each property owner forces acting as bolts and rivets, the oxide layer of them flew away immediately be brought in the position that we owned together Links. Within leaving them out is to see the slow deployment location corroded. Nickel as well as lip-black modules and vanadium also feature stainless oxidation similar but not used varied. besides chromium, nickel and lip-black modules and nitrogen oxidation also brings features such rust.

Nickel (Ni) is a common ingredient to enhance ductility, ductile, shaping properties of stainless steel. Lip-black module (Mo) makes stainless steel possesses no high corrosion resistance in acidic environments. Nitrogen (N) create stability for stainless steel at a temperature of minus (Cryogenic). Attended various components of chromium, nickel, lip-black module, nitrogen leads to the different crystal structures generate different mechanical and physical properties of stainless steel ko.

2. Separate lines

there are four main patterns of stainless steel: austenitic, ferritic, austenitic-ferritic (duplex), and martensitic.

Austenitic stainless steel is the most common. This form can be said under the steel grade SUS 301, 304, 304L, 316, 316L, 321, 310S … the containers owns minimum 7% nickel, 16% chromium, carbon (C) 12:08% max. Similar components created for the steel with corrosion resistant high temperature under quite broad, not infected during, soft, pliable, easy to weld. This steel is universal consumer to make housewares, containers, industrial hose, industrial ships, exterior architecture, the other cultivating works …

Ferritic stainless steel line is bringing such mechanical properties mild steel, but potentially higher corrosion resistance of mild steel (low carbon steel). Belonging to say this brings out the steel grade SUS 430, 410, 409 … This kind of brings about 12% take – 17% chromium. this sample, 12% Cr bearing often popular applications in architecture. type containing about 17% Cr by consumers to make home appliances, boilers, washing machines, the architecture of the house …

Austenitic ferritic-(Duplex) This is the attribute of steel “in the middle” ferritic and austenitic type of ownership is the common name DUPLEX. Under this form may include LDX 2101, SAF 2304, 2205, 253MA. duplex steel line has distilled elements Ni less popular than bearing austenitic type. DUPLEX with typical characteristics are high strength and durability flexibility universal used in the petrochemical industry sectors, the supply of paper, pulp, marine vessels … manipulated the situation in stainless steel prices climb anhydrous nickel ladder rare because then the DUPLEX is increasingly being applied more popular alternative to the steel grade of the first austenitic steels such as SUS 304, 304L, 316, 316L, 310S …

This martensitic take about 11% to 13% Cr, with load-bearing strength and hardness, corrosion resistance at a level slightly. Is used to manipulate universal blades, blades …

3. Basic features:

Inox430: magnetic, vulnerable to environmental impacts of making tarnished
Inox202: infection within, vulnerable to environmental influences that marred
Inox201: nonmagnetic (99%), stable with time, but limited direct contact with acids or salts
Inox304: nonmagnetic, consumers can bring in any environment, always shiny, ensure food safety

4. Inox infected and non-infected within the range (stainless steel magnetic attraction phenomenon and why)

4.1. Traditionally opinion stainless steel is considered not rust, no infection in about, this perspective is very much affected by the historical growth of stainless steel industries. Today, possessing a strong fast pace of the industry SS (inspection), the notion of such stainless steel is considered to be not quite right, and not science, can even cause misunderstandings about the nature of inox. Due to the requirements of different conditions, stainless steel is becoming hundreds of different lines. In slow tempo, with only a few samples are not contaminated in the range, while the majority brought about calculation.

4.2. magnetic stainless steel of diverse engagement to its metal structure. now, according to the stainless steel metal structure is divided into 4 types: martensitic, austenitic, ferritic and austenitic and ferritic types of collaboration (also called Duplex). Only with the austenite is not infectious between, and the remaining samples are magnetized. In 4 samples above, in the range of our properties are listed in the order of highest to cheapest approximately as follows: ferritic – martensitic – Duplex – austenitic. Add to slow progress, not ownership differences magnetism of ferritic and martensitic stainless steel generally. what was used in the past (in the earlier period) is 2Cr15Mn15Ni2N and 1Cr18Ni9Ti, stainless austanitic both uninfected around. besides, the environmental conditions increasingly polluted by the robustness of the industrial units advanced management, corrosion resistance of the stainless steel 2 above could not meet as previously proposed. Typically, they have a high carbon content, substances that affect resistance to most corrosive. thus two 2Cr15Mn15Ni2N and 1Cr18Ni9Ti stainless steel consumption is not diverse, the industry-specific interior and exterior decorations.

4.3. magnetic properties of stainless steel are also influenced by the passage to supply and outsourcing. austenitic stainless some property lines austenite unstable ingredients and good temperature change should be turned into martensitic and ferritic stainless steel by pressure and body temperature during practice and polish.

4.4. The relationship between magnetic stainless steel and anti-corrosion (stainless steel): magnetic and corrosion resistant stainless steel is two completely defined to meet each other in forming our stage. mention may bring, corrosion resistance of stainless steel contamination in the range is not always very good and corrosion resistance of stainless steel is not magnetic and poor.

Criteria for assessing good or not affordable stainless steel is resistant to corrosion, but not the possibility of infection. Get the 316 stainless steel is one typical example, The addition of Mo (Mo-Phil-black) austenitic stainless steel giving unstable and transforms into martensite convenient, then magnetism decreases. Besides, due to the addition of molybdenum, the chloride ion free enhanced corrosion resistance strength.

4.5. though Inox 316 (0Cr17Ni12Mo2) current use belong austenictic stainless steel, however, the reduction of carbon content (compared with 1Cr18Ni9Ti) and chemical composition of Ti (titanium) – free (versus 1Cr8Ni9Ti) lead to the stability and no temperature change in austenite stainless steel. so the pressure and temperature are reduced during preparation and polishing body made stainless steel not convert, that is the surface of austenitic stainless steel is completely transformed into martensite stainless steel, so it’s about character high up. Besides resistance to corrosion is only affected by its chemical composition, so it is not changed.

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