Structural applications of ferritic stainless steels. High performance stainless steel tubing, ferritic stainless steel, super ferritic stainless steel, corrosion, erosion, vibration, stress corrosion cracking, thermal conductivity abstract originally developed back in the early to mid1970s, the current generation of super ferritic stainless steels have now returned to popularity. Nominal sizes are nps 2 to nps 36 inclusive, with nominal average wall thickness up. Us3650709a ferritic, austenitic, martensitic stainless. The oxidation kinetics exhibited significant differences among the three ferritic stainless steels. Ferritic stainless steel properties and applications. Ferritic stainless steel is actually defined as a straight chromium nonhardenable class of. Ferritic stainless steel an overview sciencedirect topics. Brochure for architects and engineers work package 1 enduser requirements and material performance enduser information needs. It is a corrosion resistant ferritic stainless steel with excellent strength, toughness, fabrication characteristics and weldability. Stainless steel in metallurgy, stainless steel, also known as inox steel or inox from french inoxydable, is defined as a steel alloy with a minimum of 10. Installed high performance austenitic, duplex, and ferritic power plant condenser tubing by year since 2000, the use of superferritic stainless steel in other markets, such as the petrochemical industry and desalination and water recovery, has also grown significantly. Ss439 has greater resistance to corrosion and improved hightemperature stability. In this study, aisi 410s ferritic stainless steel sheets were joined with robotic laser welding method by using different welding parameters.
Stainless steel producers have an ongoing programme of development designed to produce new grades. Regular steel nonstainless would be considered ferritic because the roomtemperature microstructure is comprised of a mix of ferrite and pearlite. The primary alloying additions are chromium and nickel. A uniform and steady growing oxide scale was developed on the 430 steel with an even steel oxide interface. Jul 24, 2017 ferritic stainless steels 400 series about 20 percent of all stainless steel grades have a ferritic microstructure, with ss430 being the most widely used. The following pages will guide existing and potential stainless steel users in extending the use of ferritic grades into new and exciting application areas. Due to the lower level of carbon and the addition of titanium andor columbium, this alloy minimizes austenite formation at higher temperatures. They are magnetic, have good ductility and resistance to corrosion and oxidation. Until recently, technical difficulties prevented the cold rolling of these grades to the common 0. These terms refer to the crystal structure of the metal. Ultrasonic testing of austenitic and austeniticferritic. Ferritic stainless steel is a flexible grade of the stainless steel family with properties closely matching those of the more popular and expensive austenitic grade. Welding of ferritic martensitic stainless steels twi.
Ferritic stainless steel alloys can generally be classified into five groups, three families of standard grades groups 1 to 3 and two families of specialty grade steels groups 4 and 5. Such alloys, which are based on type 304 188 stainless steel, as shown in fig. It differs from other forms of stainless steel in two critical regards. Aug 31, 2008 new generation generalpurpose ferritic grade awm 404gp can be used to replace the workhorse austenitic grade 304 in most applications. Stainless steel is the universal name for a number of different steels used primarily for their anticorrosive element. Ferrite is soft and ductile, while pearlite is hard and brittle. Exposure to elevated temperatures such as welding leads to a refined grain structure of ferrite and lowcarbon martensite. Their low carbon content prevents hardening by heat treatment and induce a better corrosion resistance than martensitic stainless steels. Ak steel type 430 is one of the most widely used of the nonhardenable ferritic stainless steels. An overview of austenitic and ferritic stainless steels. A weldable ferritic stainless steel and a method for producing the same is provided wherein the steel consists essentially of up to 0.
Grade 410s is a ferritic stainless steel that is a low carbon variation of ferritic type 410 stainless steel. Standard specification for wrought ferritic, ferritic. Ak steel 441 offers good corrosion resistance in many. There are two great advantages to ferritic stainless steel. Yet, it is grossly underspecified for application because it is erroneously considered inferior to the austenitic. Ultrasonic testing of austenitic and austenitic ferritic stainless steel forgings bs en 102284. Ferritic stainless steels are readily welded in thin sections, but suffer grain growth with consequential loss of properties when welded in thicker sections. Ferritic stainless steels the main alloying element is chromium, with contents typically between 11 and 17%, although higher a chromium content of about 29% is found in one specialised grade. These stainless steels are magnetic and incapable of hardening through heating. Jan 26, 2020 ferritic stainless steel alloys can generally be classified into five groups, three families of standard grades groups 1 to 3 and two families of specialty grade steels groups 4 and 5.
Standard specification for welded ferriticmartensitic. Ferritic stainless steel offers a costeffective, more corrosion resistant alternative to galvanized steel. Compared to regular steel, stainless does not easily corrode, rust, or stain making stainless steels ideal if. Type 430 is the generalpurpose stainless of the ferritic group. Ferritic stainless steels with highest cr content, showing excellent atmospheric corrosion resistance even in coastal areas. Experience has shown that this can cause cold cracking problems so filler metals matching the martensitic steel should be used. The type of stainless steel material that is to be welded. Ferritic stainless steels are classified in the 400 series, usually with 10% to 30% chromium content, and are often chosen for their excellent corrosion resistance and elevated temperature oxidation resistance. Ultrasonic testing of austenitic and austeniticferritic stainless steel forgings bs en 102284. At atlantic stainless, we offer highquality austenitic, martensitic, and ferritic stainless steel grades that are available in a range of forms, grades, finishes, gauges, widths, and lengths.
It was developed as a stainless steel group that can resist oxidation and corrosion, specifically stress cracking corrosion scc. Stainless steel properties and applications of ferritic. Nominal sizes are nps 2 to nps 36 inclusive, with nominal average wall thickness up to 0. Rollable and weldable stainless steel with a high degree of tension and toughness within a wide range of temperatures both in a hardened and a toughhardened condition comprising 515 percent by weight of ferrite, 1040 percent by weight of austenite and the remainder tempered martensite. What is the difference between austenitic, ferritic, and. Friedrich teroerde chairman market development committee icda. Wide selection of austenitic and ferritic stainless steel grades.
An alternative is to weld with austenitic stainless steel fillers, type 309 for example, but the weld may then not match the tensile strength of the ferritic steel and this must be recognised in the design of the weld. Introduction to stainless steels asm international. The ferriticaustenitic stainless steels are often referred to as duplex stainless steels. It is a ferritic, nonhardenable plain chromium stainless steel with excellent finish quality. Stainless steels are stainless because their chromium content gives them remarkable resistance to corrosion.
The ferritic austenitic stainless steels are often referred to as duplex stainless steels. These grades are characterized by a very low content of nickel less than 1%. Pdf due to recent nickel price volatality, ferritic stainless steels having no or. Pdf combined welding of austenitic and ferritic stainless steel. Ferritic stainless steel ferritic steels are made up of ferrite crystals, a form of iron which contains only a very small amount up to 0. These grades are very popular in the fabrication industry, as they can withstand a. They contain enough chromium and other alloying elements to stabilize the ferritic phase at room temperature. High performance duplexes never grew in popularity for this application. Ferritic steel is a grade of stainless steel alloy that contains over 12% chromium. Ferritic grades have high ductility and are easily formed, but they do not retain their strength at high temperatures like austenitic stainless steel.
Installed high performance austenitic, duplex, and ferritic power plant condenser tubing by year since 2000, the use of super ferritic stainless steel in other markets, such as the petrochemical industry and desalination and water recovery, has also grown significantly. Ferritic stainless steels were discovered early but it was only in the 1980s that the conditions were met for their growth. In view of the continuous improvement of their properties and their growing availability, duplex stainless steels will remain an attractive solution to the future needs of designers and users in mechanical engineering. Breakaway oxidation behaviour of ferritic stainless steels. Duplex steels, consisting of mixture of ferrite and austenite. An ideal choice for structural uses in the transportation industry, its benefits come from lower life cycle costs, low maintenance needs and. Ak steel 441 provides good hightemperature strength that exceeds that of types 409 and ak steel 439 stainless steels. The second group of stainless steels are 300 series. Architectural aluminized stainless steel roofing study pdf. It may be noted that there is only one category of stainless steels that is nonmagnetic. Mar 09, 2015 ferritic grades have high ductility and are easily formed, but they do not retain their strength at high temperatures like austenitic stainless steel. The breakaway oxidation behaviour of ferritic stainless steels 430, 443 and 445 has been investigated at 1150 c in humid air. Ss409 has lower chromium and, therefore, reduced resistance to corrosion. Post weld heat treatment pwht was applied to laser.
Duplex austenitic ferritic duplex stainless steels were born and have been actively developed by european companies since 1935. Since 2000, the use of superferritic stainless steel in other markets. Since 2000, the use of super ferritic stainless steel in other markets. Superferritic stainless steels the cost effective answer. Ferritic stainless steel forms one of the four stainless steel families, the other three being austenitic, martensitic and duplex stainless steels. Ferritic stainless steels have a ferritic microstructure and small amounts of other secondary phases such as m 23 c 6 table 3. It was possible to obtain very low carbon levels at the steelmaking stage.
As the overall content of carbon increases, the proportion of. This publication is being made available in pdf format as a benefit to members and customers of asm. Daido steel is developing and producing stainless steel with properties such as freecutting, cold workability, highstrength to meet the various needs of customers. Page 2 of 5 resistance andor heat resistance andor machineability. It was developed as a stainless steel group that can resist oxidation and. Ferritic stainless steels table 2 are straightchromium 400 series types that cannot be hardened by heat treatment, and only moderately hardened by cold working. Mechanical properties of ferritic stainless steels at. What is the difference between ferritic, austenitic. The available grades of stainless steel can be classified into five basic families.
New generation generalpurpose ferritic grade awm 404gp can be used to replace the workhorse austenitic grade 304 in most applications. Types 405, 409, 430, 422 and 446 are representative of this group. While standard ferritic steels are, by far, the largest consumer group in terms of tonnage, demand for specialty grade stainless steels is increasing steadily. However, ferritic stainless steel is great for restaurant and medical counters, tables and sinks. These new grades are sometimes developed for specific end uses and sometimes to improve upon an existing grade. Ferrite absorbs such a small amount of carbon because of its body centred cubic crystal structure one iron atom at each corner, and one in the middle. Ferritic stainless steel is a type of steel with a chromium content of 10. The corrosion resistances of x6cr17 and x2crti17 ferritic stainless steels and coldrolled, lowcarbon steel, as well as circular and transversal welds of x6cr17 ferritic stainless steel, were. The stainless steel family international stainless steel. More detail on standards and grades is given below. Austenitic stainless steels have many advantages from a metallurgical point of view. These grades present similar chemical composition than ferritic grades.
Ironchromiumnickel grades corresponding to both standard aisi 300series alloys and modified versions of these alloys. X2crni12 product forms astm references sheet plate chemical composition 1. Type 430 stainless steel combines good corrosion resistance with good formability and ductility. Ferritic stainless steels are nonhardenable fecr alloys. Ferritic stainless steels are classified in the 400 series, usually with 10% to 30%. Ferritic stainless steels 400 series about 20 percent of all stainless steel grades have a ferritic microstructure, with ss430 being the most widely used. The ferritic solution international stainless steel forum.
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