R&D
Introduction
In many situations galvanic protection or painting of a mild steel surface is impractical. This is where the special oxide film formed on chromium alloy stainless steels becomes so useful.Many types of stainless steel have been developed to resist different corrosive environments and working conditions, thereby ensuring that factories are safe, structures last longer and food is hygienic. Stainless steel is even used in systems to clean up the exhaust gases from cars and power stations. A recyclable material, it can also be melted down to become new material.
Stainless steels are chromium containing steel alloys. The minimum chromium content of standardized stainless steel is 10.5%. Chromium makes the steel 'stainless', which means improved corrosion resistance, as can be seen in the chart provided.
The better corrosion resistance is due to a chromium oxide film that is formed on the steel surface. This extremely thin layer, under the right conditions, is also self-repairing. Besides chromium, typical alloying elements are molybdenum, nickel and nitrogen. Nickel is mostly alloyed to improve the formability and ductility of stainless steel. Alloying these elements brings out different crystal structures to enable different properties in machining, forming, welding etc.
four major types of stainless steel are:
Austenitic
Ferritic
Ferritic-Austenitic (Duplex)
Martensitic
Austenitic is the most widely used type of stainless steel. It has a nickel content of at least of 7%, which makes the steel structure fully austenitic and gives it ductility, a large scale of service temperature, non-magnetic properties and good weldability. The range of applications of austenitic stainless steel includes housewares, containers, industrial piping and vessels, architectural facades and constructional structures.
Ferritic stainless steel has properties similar to mild steel but with the better corrosion resistance. The most common of these steels are 12% and 17% chromium containing steels, with 12% used mostly in structural applications and 17% in housewares, boilers, washing machines and indoor architecture.
Ferritic-Austenitic (Duplex) stainless steel has both ferritic and austenitic lattice structures - hence common name: duplex stainless steel. This steel has some nickel content for a partially austenitic lattice structure. The duplex structure delivers both strength and ductility. Duplex steels are mostly used in petrochemical, paper, pulp and shipbuilding industries.
Martensitic stainless steel contains mostly 11 to 13% chromium and is both strong and hard with moderate corrosion resistance. This steel is mostly used in turbine blades and in knives.
; win.focus();)
Introduction:Martensitic Stainless Steels
Martensitic steels have the highest strength but also the lowest corrosion resistance of the stainless steels.
Microstructure image of a
martensitic stainless steel
Martensitic steels with high carbon contents are used for tool steels.
Due to their high strength in combination with some corrosion resistance, martensitic steels are suitable for applications where the material is subjected to both corrosion and wear. An example is in hydroelectric turbines.
Super-pure ferrite stainless steel is the earliest new material developed by TBS R&D Center. It has good resistance against inter-crystal corrosion and definite resistance against corrosion by oxidizing and organic acid mediums. If molybdenum, silicon and aluminum are added, the resulting steel will become resistant to heat, oxidation and corrosion. With good heat conductivity and dimension stability, it is widely used for production of multi-purpose plate heat exchangers and pipe heat exchangers. Sold at a greatly reduced price, this steel is comparable to normal stainless steel. TBS steel grades currently include SUS409L, 430LX, 436L etc.
In a word, TBS prides itself on its capability to produce varied pipes of all steel structures as well as duplex and super pure ferritic structures.
Martensitic steels have the highest strength but also the lowest corrosion resistance of the stainless steels.
Microstructure image of a
martensitic stainless steel
Martensitic steels with high carbon contents are used for tool steels.
Due to their high strength in combination with some corrosion resistance, martensitic steels are suitable for applications where the material is subjected to both corrosion and wear. An example is in hydroelectric turbines.
Super-pure ferrite stainless steel is the earliest new material developed by TBS R&D Center. It has good resistance against inter-crystal corrosion and definite resistance against corrosion by oxidizing and organic acid mediums. If molybdenum, silicon and aluminum are added, the resulting steel will become resistant to heat, oxidation and corrosion. With good heat conductivity and dimension stability, it is widely used for production of multi-purpose plate heat exchangers and pipe heat exchangers. Sold at a greatly reduced price, this steel is comparable to normal stainless steel. TBS steel grades currently include SUS409L, 430LX, 436L etc.
In a word, TBS prides itself on its capability to produce varied pipes of all steel structures as well as duplex and super pure ferritic structures.
Introduction:Ferritic Stainless Steels
These steels are, in principle, ferritic at all temperatures. This is achieved by a low content of austenite forming elements, mainly nickel, and a high content of ferrite forming elements, mainly chromium.
The older types, such as AISI 430, were mainly used for household utensils and other purposes where corrosion conditions are not particularly demanding.
Steels with high chromium content, such as AISI 446 with 27% chromium, are used at high temperatures where their resistance to sulphurous flue gages is an advantage. However, the risk of 475 °C embitterment and precipitation of brittle sigma phase in high-chromium steels must always be taken into consideration.
Today's ferritic steels, such as S44400 with extremely low carbon and nitrogen contents, find greatest use where there is a risk of stress-corrosion cracking.
Ferritic steels have slightly higher yield strength (Rp 0.2) than austenitic steels, but they have less elongation at fracture. Another characteristic that distinguishes ferritic steel from austenitic material is that ferritic steels have much lower strain hardening.
These steels are, in principle, ferritic at all temperatures. This is achieved by a low content of austenite forming elements, mainly nickel, and a high content of ferrite forming elements, mainly chromium.
The older types, such as AISI 430, were mainly used for household utensils and other purposes where corrosion conditions are not particularly demanding.
Steels with high chromium content, such as AISI 446 with 27% chromium, are used at high temperatures where their resistance to sulphurous flue gages is an advantage. However, the risk of 475 °C embitterment and precipitation of brittle sigma phase in high-chromium steels must always be taken into consideration.
Today's ferritic steels, such as S44400 with extremely low carbon and nitrogen contents, find greatest use where there is a risk of stress-corrosion cracking.
Ferritic steels have slightly higher yield strength (Rp 0.2) than austenitic steels, but they have less elongation at fracture. Another characteristic that distinguishes ferritic steel from austenitic material is that ferritic steels have much lower strain hardening.
; win.focus();)
Introduction:Austenitic Stainless Steels
This type of stainless steel is dominant in the market. The group includes the very common AISI 304 and AISI 316 steels, but also the higher-alloy AISI 310S and ASTM N08904.
Austenitic steels are characterised by their high content of austenite-formers, especially nickel. They are also alloyed with chromium, molybdenum and sometimes with copper, titanium, niobium and nitrogen. Alloying with nitrogen raises the yield strength of the steels.
Austenitic stainless steels have a very wide range of applications, e.g. in the chemical industry and the food processing industry.
The molybdenum-free steels also have very good high-temperature properties and are therefore used in furnaces and heat exchangers. Their good impact strength at low temperatures is often exploited in apparatus such as vessels for cryogenic liquids.
Austenitic steels cannot be hardened by heat treatment. They are normally supplied in the quench-annealed state, which means that they are soft and highly formable.
Cold working increases their hardness and strength. Certain steel grades are therefore supplied in the cold stretched or hard rolled condition.
The image shows the microstructure of an
austenitic stainless steel, type ASTM 304L.
This type of stainless steel is dominant in the market. The group includes the very common AISI 304 and AISI 316 steels, but also the higher-alloy AISI 310S and ASTM N08904.
Austenitic steels are characterised by their high content of austenite-formers, especially nickel. They are also alloyed with chromium, molybdenum and sometimes with copper, titanium, niobium and nitrogen. Alloying with nitrogen raises the yield strength of the steels.
Austenitic stainless steels have a very wide range of applications, e.g. in the chemical industry and the food processing industry.
The molybdenum-free steels also have very good high-temperature properties and are therefore used in furnaces and heat exchangers. Their good impact strength at low temperatures is often exploited in apparatus such as vessels for cryogenic liquids.
Austenitic steels cannot be hardened by heat treatment. They are normally supplied in the quench-annealed state, which means that they are soft and highly formable.
Cold working increases their hardness and strength. Certain steel grades are therefore supplied in the cold stretched or hard rolled condition.
The image shows the microstructure of an
austenitic stainless steel, type ASTM 304L.
; win.focus();)
Introduction:Ferritic-Austenitic Stainless Steels
This group of steels is intermediate in terms of structure and alloy content between ferritic and austenitic steels.
The microstructure shows an
image of a duplex 3RE60 grade.
The main characteristic that differentiates ferritic-austenitic steels from austenitic and ferritic steels is that they have a higher yield strength and tensile strength. They are therefore often used in dynamically stressed machine parts, e.g. suction rolls for paper machines. New areas of application are within the oil, gas and petrochemical sector, seawater-bearing systems and the offshore industry.
These steels are normally named Duplex stainless steels due to the two phases present in the microstructure.
This group of steels is intermediate in terms of structure and alloy content between ferritic and austenitic steels.
The microstructure shows an
image of a duplex 3RE60 grade.
The main characteristic that differentiates ferritic-austenitic steels from austenitic and ferritic steels is that they have a higher yield strength and tensile strength. They are therefore often used in dynamically stressed machine parts, e.g. suction rolls for paper machines. New areas of application are within the oil, gas and petrochemical sector, seawater-bearing systems and the offshore industry.
These steels are normally named Duplex stainless steels due to the two phases present in the microstructure.
Introduction:About anti-bacteria Steel
It is wiser to create an environment with no harmful bacteria rather than rack our brains to kill them to ensure our health; thus TBS's anti-bacteria stainless steel made its debut through the precise adjustment & special treatment of multiple components as well as copper. It has acquired CMA certification & national patent rights and is certified by the National Microscopic Testing Center. It will find wide applications in water transport, kitchenware, tableware, medical equipment, toys, package, electronic appliances as well as public utilities as it can inhibit the growth of 99.5% coliform and yellow staphylococcus.
Water pipes made with anti-bacteria stainless steel serves healthy and clean water and thereby have caught remarkable attentions from our counterparts.
It is TBS's mission to contribute more to health and TBS will never subside to strengthen its efforts to serve more.
It is wiser to create an environment with no harmful bacteria rather than rack our brains to kill them to ensure our health; thus TBS's anti-bacteria stainless steel made its debut through the precise adjustment & special treatment of multiple components as well as copper. It has acquired CMA certification & national patent rights and is certified by the National Microscopic Testing Center. It will find wide applications in water transport, kitchenware, tableware, medical equipment, toys, package, electronic appliances as well as public utilities as it can inhibit the growth of 99.5% coliform and yellow staphylococcus.
Water pipes made with anti-bacteria stainless steel serves healthy and clean water and thereby have caught remarkable attentions from our counterparts.
It is TBS's mission to contribute more to health and TBS will never subside to strengthen its efforts to serve more.
Didn't find what you're looking for? Post a buying lead.
Company Info
Shanghai Tianbao Stainless Steel Co., Ltd.
[China]
[Verified Member]
City: Shanghai
Province/State: Shanghai
Country/Region : China
Business Type:Manufacturer
Online Postings: Products