Stainless Steel Grades

Stainless steel is a special category of different iron base alloys which are formulated of different elements like Iron, Chromium, Nickel. These iron base alloys have good mechanical properties and manufacturing characteristics and are corrosion resistance to sea water and concentrated acids.

There are many different grades in this category which have their unique characteristics and properties in different conditions and environments.

Grade 304/304L

Stainless Steel Grade 304 is the standard 18/8 (18% chrome, 8% nickel) austenitic stainless steel. It is a non-magnetic alloy in the annealed condition, however, becomes magnetic as it is cold worked. It is the most ordinarily utilized of all stainless grades. T304 can be effortlessly welded and is the preferred for many deep drawn, spun or formed parts due to its high ductility.

Stainless Steel Grade 304L has oxidation resistance to a maximum temperature of 1650°F (899°C) continuous without considerable scaling. The maximum temperature for intermittent presentation is 1500°F (816°C). Since 304L is an additional low-carbon variety of 304 it can frequently be utilized in the “as-welded” condition (without annealing), even in severe corrosive conditions, except for applications indicating stress relief. 304L has good welding qualities and can be welded by all standard strategy; however, consideration should be paid to maintain a strategic distance from weld “hot cracking”. To relieve stress during severe forming or spinning welding may be followed by annealing.

Chemical Composition

GradeCMnSiPscrNiN
304 (min-max)0 - 0.070 - 2.00 - 0.750 - 0.0450 - 0.03017.5 - 19.58.0 - 10.50 - 0.10
304L (min-max)0 - 0.0300 - 2.0​0 - 0.75​0 - 0.045​0 - 0.03017.5 - 19.5​8.0 - 12.00 - 0.10​

Mechanical Properties

Spec304304L
Tensile Strength (min)515485
Yield205170
Elongation (% in 50mm)4040
Hardness (Brinell)201201

Physical Properties

Density (Kg/m3)Elastic Modulus (GPa)Thermal ConductivitySpecific Heat 0-100°CThermal ExpansionElectrical Resistivity (n.m)
304/L79005001d720

Applications:

Air Bag Sensors, Clamps, Bellows, Flexible Hoses, Hinges, Cryogenic Components, Surgical Instruments, Pressure Vessels, Oil Well, Filter Screen, Hypodermic Needles, Medical Parts, Tubing

Grade 316L

Stainless Steel Grade 316L is an austenitic chromium-nickel stainless steel includes molybdenum. This addition increases corrosion resistance, enhances resistance to pitting chloride ion solutions and give expanded strength at high temperatures. Properties are same as to those of type 304 aside from that 316 are somewhat stronger at high temperatures. Corrosion resistance is enhanced, specifically against sulfuric, hydrochloric, acetic, formic and tartaric acids, acid sulphates and alkaline chlorides.

Stainless Steel Grade 316L is a low carbon austenitic chromium-nickel stainless steels with corrosion resistance same as type 316 however with resistance to intergranular corrosion following welding.

Chemical Composition

GradeCrNiMocMnNSipSFe
316L (min-max)16.50 - 18.5010.00 - 13.002.00 - 2.500 - 0.040 - 2.000 - 0.110 - 1.000 - 0.040 - 0.03bal
316 (min-max)2b2c2d2d2d2d2d2d2d2d

Mechanical Properties

Spec0.2% Proof StressTensile Strength, minTensile strength, maxElongation, 5.65√S0 and 4DReduction of AreaHardness (Brinell)Impact Strength (Room Temp)
Bars up to and including 1 3/8” (35mm) diameter or section205 N/mm2515 N/mm2700 N/mm235%40%<270Typically >88J
Bars greater than 1 3/8” (35mm) diameter or section205 N/mm2515 N/mm2700 N/mm220%40%<270Typically >88J

Physical Properties

SpecDensity (Kg/m3)Magnetic Permeability (20°C)Young’s Modulus (kN/mm2)Specific Electrical Resistance, 20°C (µΩ-m)Mean coefficient of thermal expansion, 20-100°C (m/m/°C)Specific Heat, 20°C (J/kg.K)Thermal conductivity, 20°C (W/m.K)
316L8000<1.051930.7415.9 x 10-650016.3

Applications: Chemical and petrochemical industry, in food processing, pharmaceutical equipment, medical devices, in potable water, wastewater treatment, in marine applications and architectural applications near the seashore or in urban areas.

Grade 303

The 303 grade stainless steel has the best machinability among the Austenitic stainless steel grades. Like the 304 and 316 grades, it is one of the most widely used stainless steel grades around the world. The reason of better machinability is the sulfur inclusion of the 303 grade. However, although the sulfur increases its machinability; it also decreases the corrosion resistance of the material. Therefore the 303 grade has much lower corrosion resistance than 304 grade.

​The production of 303 is more difficult than other grades. The chemical composition’s balance and the homogenous distribution of the elements are very important. The homogenous distribution of the alloys is adjusted during annealing. With a careful and correct annealing process, the end results of higher machinability and mechanical properties will be obtained. However a poor annealing process means the material may cause difficulties in machining.

 

Chemical Composition

GradeCMnSiPscrNi
303 (min-max)0 - 0.150 - 2.000 - 1.000 - 0.200.15 - 017.0 - 19.08.0 - 10.0

Mechanical Properties

Grade303
Tensile Strength (MPa)-
Yield Strength 0.2% Proof (MPa)-
Elongation (% in 50mm)-
Hardness (Brinell)262 max

Physical Properties

Grade303
Density (kg/m3)8027
Elastic Modulus (GPa)193
Mean Coefficient of Thermal Expansion (μm/m/°C) 0-100°C17.3
Thermal Conductivity (W/m.K) at 100°C16.3
Electrical Resistivity (nΩ.m)720
Specific Heat 0-100°C (J/kg.K)500

Applications: Bushings, bearings, nuts, and bolts

UNS32205/31803 DUPLEX 2205

Duplex 2205 are nitrogen improved duplex stainless steel that was created to combat normal corrosion issues experienced with the 300 series stainless steels. “Duplex” define a family of stainless steels that are neither completely austenitic, like 304 stainless, nor absolutely Ferritic, like 430 stainless. The structure of 2205 duplex stainless steel comprises of austenite pools encompassed by a persistent ferrite phase.  In the annealed condition, 2205 consist around 40-50% ferrite. Frequently referred to as the workhorse grade, Duplex 2205 are the most generally utilized grades in the duplex family of stainless steels. One of the benefits of a duplex architecture is that it consolidates the great characteristics of a Ferritic alloy (stress corrosion cracking resistance and high strength) with those of an austenitic alloy (ease of fabrication and corrosion resistance). Use of 2205 Duplex stainless steel should be restricted to temperatures below 600° F. Extended high temperature exposure can embrittled 2205 stainless steel.

Chemical Composition

GradeCrNiMocNSipSFe
Duplex 2205 (min-max)22.00 - 23.004.50 - 6.503.00 - 3.500 - 0.030.14 - 0.200.20 - 0.700 - 0.030 - 0.02bal

Mechanical Properties

0.2% Proof StressTensile StrengthElongation, 5.65√S0Reduction of areaHardness (Brinell)Impact Strength (Room Temp)Impact Strength (-46°C) : LongitudinalImpact Strength (-46oC) : Transverse
450 N/mm2655 N/mm225%45%<27080J (av)100-260mm 45J (35J min)50-260mm 45J (35J min)

Physical Properties

Density (Kg/m3)Magnetic Permeability (20°C)Young’s Modulus (kN/mm2)Specific Electrical Resistance, 20°C (µΩ.m)Mean coefficient of thermal expansion, 20-100°C (m/m/°C)Specific Heat, 20°C (J/kg.K)Thermal conductivity, 20°C (W/m.K)
7810<501900.8511 x 10-640015

Applications: Chemical processing, transport and storage – pressure vessels, tanks, piping, and heat exchangers, Oil and gas exploration and processing equipment – piping, tubing, and heat exchangers

S32550/F61

Super duplex UNS S32550/ F61 is a stainless steel grade that offers excellent corrosion resistance in a wide variety of corrosive chemicals including sulphuric, phosphoric and nitric acids. In Seawater and other chloride containing environments 32550 also provides outstanding resistance to pitting and crevice corrosion, with Critical Pitting Temperature exceeding 50°C.

Excellent ductility and impact strength at both ambient and sub-zero temperatures combine with a high resistance to abrasion, erosion and cavitation erosion. UNS S32550 Displays superior corrosion resistance in most media. Also, 2550 typically out performs duplex alloy 2205. It performs well in sulphuric, phosphoric, and nitric and shows excellent resistance to organic acids such as acetic and formic acid. Highly reducing media should be avoided.

Chemical Composition

GradeCrNiMoCuCMnNSiPSFe
Ferralium 255 (Min - Max)24.50 - 26.505.50 - 6.503.10 - 3.801.50 - 2.000 - 0.250.80 - 1.200.20 - 0.250 - 0.700 - 0.0250 - 0.005Bal

Mechanical Properties

Ferralium 255 SpecBars up to and including 4.0” (100mm)Bars greater than 4.0” (100mm) and up to 12.0” (300mm)Bars greater than 12.0” (300mm)
0.2% Proof Stress586 N/mm2586 N/mm2570 N/mm2
Tensile Strength790 N/mm2790 N/mm2760 N/mm2
Elongation, 5.65√S025%25%25%
Reduction of area50%50%50%
Hardness (Brinell)220-270220-270220-270
Impact Strength (Room Temp)80J (av)80J (av)80J (av)
Impact Strength (-46degC)45J av (35J min)45J av (35J min)45J av (35J min)

Physical Properties

Density (Kg/m3)7810
Magnetic Permeability (20°C)33
Young’s Modulus (kN/mm2)199
Specific Electrical Resistance, 20°C (µΩ.m)0.80 x 10-6
Mean coefficient of thermal expansion, 20-100°C (m/m/degC)11.1 x 10-6
Specific Heat, 20°C (J/kg.K)475
Thermal conductivity, 20°C (W/m.K)14.2
Fracture Toughness, KQ (MPa/m2)98

Applications: Manufacturing bare forgings or forged and machined products for applications involving high temperature service.

SS321

SS 321 is titanium settled austenitic stainless steel with greater general corrosion resistance. It has phenomenal resistance to intergranular corrosion after presentation to temperatures in the chromium carbide precipitation scope of 800–1500°F (427–816°C). The alloy maintains oxidation to 1500°F (816°C) and has higher creep and stress rupture properties than alloys 304 and 304L. It also maintains good low temperature toughness. Alloy 321H is the higher carbon (0.04–0.10) version of the alloy. It was produced to improve creep resistance and for higher strength at temperatures above 1000°F (537°C). In most occurrences, the carbon content of the plate enables dual certification. Alloy 321 cannot be hardened by heat treatment, just by cold working. It can be effectively welded and processed by standard shop fabrication practices.

Chemical Composition

GradeCrNiMoCuTiCMnSiPSNFe
321 (min-max)17.0 - 19.09.0 - 12.00 - 0.750 - 0.755x(C+N) - 0.700 - 0.080 - 2.00.25 - 1.00 - 0.040 - 0.030 - 0.1Bal

Mechanical Properties

Temperature, °F68400600800100012001400
Ultimate Tensile Strength, ksi8462626259.545.527.5
.2% Yield Strength, ksi3820.5181716.51614

Physical Properties

Density (g/cm3)Electrical Resistivity (µΩ·cm)Thermal Conductivity (W/mK)Magnetic Permeability (H/m at 200 Oersteds)Specific Heat (kJ/kg/K)Melting Range (°C)
8.097216.0≤ 1.020.501371 - 1399

Applications: Chemical and petrochemical industry, in food processing, pharmaceutical equipment, medical devices, in potable water, wastewater treatment, in marine applications and architectural applications near the seashore or in urban areas.

SS317 / 317L

Type 317 is an austenitic chromium-nickel stainless steel with phenomenal corrosion resistance; its high Molybdenum content improves the grade´s superior pitting resistance. It is the most corrosion resistant of the 300 series alloys and possesses the highest tensile and creep strength properties at high temperatures.

Type 317L is a low carbon austenitic chromium-nickel stainless steel that can be utilized in applications where it is not possible to anneal after welding and where maximum corrosion resistance is needed. It gives good oxidation resistance in intermittent service to 1600°F and in continuous service to 1700°F.

Chemical Composition

GradeFeCrNiMoMnSiCPS
31761%19%13%3.50210.0800.0450.030

Mechanical Properties

PropertiesMetricImperial
Tensile Strength620 MPa89900 psi
Yield strength275 MPa39900 psi
Elastic modulus193 GPa27993 ksi
Poisson's ratio0.27-0.300.27-0.30
Elongation at break (in 50 mm)45%45%
Hardness, Rockwell B8585

Physical Properties

PropertiesMetricImperial
Density8 g/cm30.289 lb/in³
Melting point1370°C2550°F

Applications: Chemical and petrochemical industry, in food processing, pharmaceutical equipment, medical devices, in potable water, wastewater treatment, in marine applications and architectural applications near the seashore or in urban areas.

S 904L

904L is a high-alloy austenitic stainless steel which consist low carbon content. The grade is designed for use under severe corrosive conditions. It has been application demonstrated over many years and was initially created to resist corrosion in dilute sulfuric acid. It is standardized and accepted for pressure vessel utilize in different countries. Fundamentally, 904L is completely austenitic and is less sensitive to precipitation ferrite and sigma phases than standard austenitic grades with very high molybdenum content. Distinctively, because of the combination of relatively high contents of chromium, nickel, molybdenum and copper 904L Stainless Steel has very good resistance to general corrosion, especially in sulfuric and phosphoric conditions.

Chemical Composition

GradeCrNiMoCuTiCMnSiPSNFe
904L (min-max)17.0 - 19.09.0 - 12.00 - 0.750 - 0.755x(C+N) - 0.700 - 0.080 - 2.00.25 - 1.00 - 0.040 - 0.030 - 0.1Bal

Mechanical Properties

Temperature, °F68400600800100012001400
Ultimate Tensile Strength, ksi8462626259.545.527.5
.2% Yield Strength, ksi3820.5181716.51614

Physical Properties

GradeDensity (kg/m3)Elastic Modulus (GPa)Mean Co-eff of Thermal Expansion (0-100°C)Thermal Conductivity at 20°C (W/m.K)Specific Heat 0-100°C (J/kg.K)Elec Resistivity (nΩ.m)
904L79001901511.5500952

Applications: Cooling equipment for seawater, Chemical processing of sulphuric, phosphoric and acetic acids, Heat exchangers, Condenser tubes, Gas washing, Control and instrumentation, Oil and gas industry, Pharmaceutical production, Wiring in electrostatic precipitators

SS410

Grade 410 Stainless Steels are universally useful martensitic stainless steels containing 11.5% chromium, which gives good corrosion resistance properties. However, the corrosion resistance of grade 410 steels can be further improved by a series of processes for example, hardening, tempering and polishing. Quenching and tempering can harden grade 410 steels. The main applications of Stainless Steel 410 involve mild corrosion, heat resistance and high strength. Martensitic stainless steels are fabricated by utilizing techniques that require final heat treatment. These grades are less resistant to corrosion when compared to that of austenitic grades. Their working temperatures are frequently influenced by their loss of strength at high temperatures, because of over-tempering and loss of ductility at sub-zero temperatures.

Chemical Composition

GradeFeCrNiMoMnSiCPS
41061%19%13%3.50210.0800.0450.030

Mechanical Properties

PropertiesMetricImperial
Tensile Strength620 MPa89900 psi
Yield strength275 MPa39900 psi
Elastic modulus193 GPa27993 ksi
Poisson's ratio0.27-0.300.27-0.30
Elongation at break (in 50 mm)45%45%
Hardness, Rockwell B8585

Physical Properties

PropertiesMetricImperial
Density8 g/cm30.289 lb/in³
Melting point1370°C2550°F

Applications: Cutlery, Steam and gas turbine blades, Kitchen utensils, Bolts, nuts, screws, Pump and valve parts and shafts, Mine ladder rugs, Dental and surgical instruments, Nozzles, Hardened steel balls and seats for oil well pumps

SS 17-4 PH

S.S.17-4 PH is one of the most common grades of martensitic, precipitation hardenable (PH) alloys. 17-4 gives a remarkable combination of high strength, very good mechanical properties at temperatures up to 600°F (316°C), and short-duration, low-temperature heat treatments which minimize war page and scaling. Its good corrosion resistance, formability as well as weldability make it perfect for a different variety of applications in aerospace, petrochemical, and other structural applications. In the annealed condition Stainless Steel 17-4 PH keeps up high mechanical properties, making some forming operations difficult.

Chemical Composition

GradeFeCrNiMoMnSiCPS
17-4 PH61%19%13%3.50210.0800.0450.030

Mechanical Properties

PropertiesMetricImperial
Tensile Strength620 MPa89900 psi
Yield strength275 MPa39900 psi
Elastic modulus193 GPa27993 ksi
Poisson's ratio0.27-0.300.27-0.30
Elongation at break (in 50 mm)45%45%
Hardness, Rockwell B8585

Physical Properties

PropertiesMetricImperial
Density8 g/cm30.289 lb/in³
Melting point1370°C2550°F

Applications: Nuclear reactor, Aircraft and gas turbines, Oil field, Chemical process components, Paper mill

Duplex 2507 / UNS S32750

Duplex 2507 is a super duplex stainless steel intended for applications which request for exceptional strength and corrosion resistance. Alloy 2507 includes 25% chromium, 4% molybdenum, and 7% nickel. This high molybdenum, chromium and nitrogen content results in magnificent resistance to chloride pitting and crevice corrosion attack and the duplex structure provides 2507 with unique resistance to chloride stress corrosion cracking. Utilization of Duplex 2507 should be limited to applications underneath 600° F (316° C). Expanded elevated temperature exposure can reduce both the toughness and corrosion resistance of alloy 2507. Duplex 2507 have magnificent mechanical properties. Frequently a light gauge of 2507 materials can be utilized to accomplish the same design strength of a thicker nickel alloy. The resulting savings in weight can dramatically cut the overall expense of fabrication.

Chemical Composition

GradeFeCrNiMoMnSiCPS
250761%19%13%3.50210.0800.0450.030

Mechanical Properties

PropertiesMetricImperial
Tensile Strength620 MPa89900 psi
Yield strength275 MPa39900 psi
Elastic modulus193 GPa27993 ksi
Poisson's ratio0.27-0.300.27-0.30
Elongation at break (in 50 mm)45%45%
Hardness, Rockwell B8585

Physical Properties

PropertiesMetricImperial
Density8 g/cm30.289 lb/in³
Melting point1370°C2550°F

Applications: Desalination Equipment, Chemical process pressure vessels, piping and heat exchangers, Marine Applications, Flue Gas Scrubbing Equipment, Pulp & Paper Mill Equipment, Offshore Oil production/technology, Oil and gas industry equipment

Zeron 100/ UNS S32760

Zeron 100 is a super duplex stainless steel. It is a highly alloyed stainless steel intended for use in forceful situations. High strength, toughness, magnificent corrosion resistance and its resistance to corrosion in a wide range of organic and inorganic acids is only a couple of attributes that make this duplex stainless steel attractive to a variety of industries. In conclusion, it is highly resistant to strong alkalis and resists corrosion in various non-oxidizing acids. Utilization of this super duplex stainless steel is not recommended when it includes extended exposure to temperatures greater than 572° F. This exposure causes a considerable reduction in toughness. Notice the chemical composition of duplex 2507 and Zeron 100 are same; however, Zeron 100 contains marginally more copper and tungsten. The copper substance (min. 0.5, max 1.0) grants magnificent resistance to corrosion in many non-oxidizing and mineral acids like hydrochloric and sulfuric acid.

Chemical Composition

GradeFeCrNiMoMnSiCPS
Zeron 10061%19%13%3.50210.0800.0450.030

Mechanical Properties

PropertiesMetricImperial
Tensile Strength620 MPa89900 psi
Yield strength275 MPa39900 psi
Elastic modulus193 GPa27993 ksi
Poisson's ratio0.27-0.300.27-0.30
Elongation at break (in 50 mm)45%45%
Hardness, Rockwell B8585

Physical Properties

PropertiesMetricImperial
Density8 g/cm30.289 lb/in³
Melting point1370°C2550°F

Applications: Oil and gas industry applications, Pollution control, Pulp and paper, Power generation, Flue-gas desulfurization