Stainless steel , stainless steel , also known as " Stainless steel attached to the name of a British steel industry expert is Mr. Harry Brearley . When in 1913 , he invented a special type of steel resistant to corrosion high , by reducing the carbon content in cromvao down and the steel components ( 0:24 % C and 12.8 % Cr ) .
Then in the German steel company Krupp steel continue to improve this by adding the element nickel in steel to increase resistance to corrosion and acids to soften more easily worked . On the basis of these two inventions that two types of steel grade 400 and 300 was born just before the First World War the most . After the war , the 20th year of the 20th century , a British steel industry expert Mr. W. H Hatfield continue to research and develop the idea of stainless steel . By combining the different ratio between nickel and chromium in steel components , he came out with a new stainless steel 18/8 the rate of 8 % Ni and 18 % Cr steel grade 304 is used of today. He is also the inventor of the 321 steel components by adding titanium to steel ratio of 18/8 above .
In the metallurgical industry , the term stainless steel ( inox ) is used to specify a minimum danghop containing iron and chromium 10.5 % . Called " stainless steel " but actually it's just an alloy of iron discoloration or not corrode as easily as other common loaithep . This material can also called corrosion-resistant steel . Typically , there are many different ways to stainless steel applications for the various surfaces to increase the longevity of items . In life , they appear everywhere as the cutting blade or strap watches ...
The ability to resist oxidation from the ambient air at normal temperature of stainless steel is due to the ratio of chromium in alloy ( as low as 13 % and can be up to 26 % in the case of work in harsh working environments ) . Oxidation state of chromium is chromium oxide often ( III ) . When chromium alloy steel in contact with air , a very thin layer of chromium III oxide appears on the material surface , this layer is so thin that you can not see with the naked eye , which means that the metal surface is shiny . However, they are not completely effective and voinuoc air layer should protect the steel underneath . This phenomenon is called oxidation rust in materials engineering . We can see this phenomenon for some other metals such as aluminum and zinc in .
When the body is made of stainless steel links together with the force as bolts and rivets , the oxide layer of fly they can be lost even in the position where they are connected to each other . When disassembled them , you can see the corrosion that position .
Nickel ( Ni ) is a common component to enhance viscosity , easy bending , shaping properties of stainless steel . Model - lip- black ( Mo ) made of stainless steel has high corrosion resistance in acidic environments . Nitrogen ( N ) creates stability for stainless steel in subzero temperatures ( cold environment ) .
Austenitic stainless steel is the most common . This may include line of the steel grade SUS 301 , 304 , 304L , 316 , 316L , 321 , 310S ... This type contains at least 7 % nickel , 16 % chromium , carbon ( C ) 0:08 % max . Such components created for this type of steel resistant to corrosion in high temperature range is quite wide , not infected , flexible , pliable , easy to weld . This steel is used to make many household items , container , industrial pipes , industrial vessels , exterior architecture , buildings and other construction ...
Is ferritic stainless steels have mechanical properties similar to mild steel , but have high corrosion resistance than mild steel ( low carbon steel ) . This may include line of the steel grade SUS 430 , 410 , 409 ... This type contains about 12 % - 17 % chromium . This category, with 12 % Cr is often more in architectural applications . Type containing about 17 % Cr are used to housewares , boilers , washing machines , the architecture of the ...
Austenitic - Ferritic ( Duplex ) This type of steel has properties " in the middle " type of Ferritic and Austenitic collectively called DUPLEX . This line belongs to mention LDX 2101 , SAF 2304 , 2205 , 253MA . Duplex steel composition containing less than Ni austenitic type . DUPLEX have the typical characteristics of high-strength durability and flexibility widely used in petrochemical industry , paper , pulp , marine vessel fabrication ... Given the escalating price of stainless steel by nickel scarce DUPLEX line is increasingly more applications to replace some lines of steel austenitic steels such as SUS 304 , 304L , 316 , 316L , 310S ...
Martensitic type contains about 11 % to 13 % Cr , bearing strength and hardness , corrosion resistance relative degree . Widely used to manufacture turbine blades , knives ...
The characteristics of the stainless steel group can be viewed from the perspective compared to their low carbon steel . Most general terms , stainless steel :
Corrosion resistant than
Toughness at low temperatures better
The reaction was less than ( only with austenitic steel )
The features that really true for them , and austenitic steels can vary quite a lot for their steel and other alloy steels .
The mechanical properties related to the field of application of stainless steel , but also influenced by device and fabrication method .
Magnetic Alloy group 1 of durable wrought Speed 2 corrosion resistance ability of
Not very high austenitic cold Cao Ren
There Duplex Average Very high None
There ferrite Average Average None
There Martensit Average Average I and Ram
There hardening Average Average aging
( 1 ) - Attraction of magnets for steel . Note , some steels are a magnet when Cold worked .
Viscosity Group alloys at high temperatures Working temperature Working thap3 weldability
Austenitic very high very high very high very good
Duplex Medium Low Medium High
Ferrite Medium High Low Low
Martensit Low Low Low Low
Hardening Medium Low Low High
( 3 ) - Measured with toughness or ductility near 0 ° C. Austenitic stainless steel is kept at a low temperature ductility .
There are many variations of stainless steel and the American Iron and Steel Institute ( AISI ) previously defined a number of standard grade ingredients , and is still widely used today. Today, SAE and ASTM standard of AISI according to the provisions of its steels , UNS indexed character is 1 + 5 digits for the new steel grade . Scope the full indexing of the stainless steel they used in the Iron and Steel Society ( ISS ) , and manual SEA / ASTM index of system integration . The steel grade that no other standard indicators , which are used in other countries or international regulations or regulations for such specialized manufacturer of steel wire welding standards .