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Stainless Steel - Grade 304 (UNS S30400)

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Grade 304 is a standard "18/8" stainless. It is the most versatile and most widely used stainless steel available, even though a wide range of alternatives are available; and has excellent forming and welding characteristics. The balanced austenitic structure of Grade 304 enables it to be severely deep drawn without intermediate annealing. This means that this grade steel is dominant in the manufacture of drawn stainless parts such as sinks, hollow-ware and saucepans. For these applications, it is common to use special "304DDQ" (Deep Drawing Quality) variants. Grade 304 can be readily braked or roll-formed into a variety of components for applications in the industrial, architectural, and transportation fields. It also has outstanding welding characteristics. Post-weld annealing is not required when welding thin sections.

Grade 304L, the low carbon version of 304, does not require post-weld annealing and is therefore extensively used in heavy gauge components (over about 6mm). Grade 304H with its higher carbon content is used in applications at elevated temperatures. The austenitic structure also gives these grades excellent toughness, even down to cryogenic temperatures.

Key Properties

These properties are specified for flat rolled product (plate, sheet, and coil) in ASTM A240/A240M. Similar but not necessarily identical properties are specified for other products such as pipe and bar in their respective specifications.

Composition

Table 1. Typical composition ranges for 304-grade stainless steel

Grade C Mn Si P S Cr Mo Ni N
304 min.
max.
-
0.08
-
2.0
-
0.75
-
0.045
-
0.030
18.0
20.0
- 8.0
10.5
-
0.10
304L min.
max.
-
0.030
-
2.0
-
0.75
-
0.045
-
0.030
18.0
20.0
- 8.0
12.0
-
0.10
304H min.
max.
0.04
0.10
-
2.0
-
0.75
-0.045 -
0.030
18.0
20.0
- 8.0
10.5
-

Mechanical Properties

Table 2. Typical mechanical properties of 304-grade stainless steel

Grade Tensile Strength (MPa) min Yield Strength 0.2% Proof (MPa) min Elongation (% in 50 mm) min Hardness
Rockwell B (HR B) max Brinell (HB) max
304 515 205 40 92 201
304L 485 170 40 92 201
304H 515 205 40 92 201

304H also requires a grain size of ASTM No 7 or coarser.

Physical Properties

Table 3. Typical physical properties of 304-grade stainless steel in the annealed condition

Grade Density (kg/m3) Elastic Modulus (GPa) Mean Coefficient of Thermal Expansion (μm/m/°C) Thermal Conductivity (W/m.K) Specific Heat 0-100 °C (J/kg.K) Electrical Resistivity (nΩ.m)
0-100 °C 0-315 °C 0-538 °C at 100 °C at 500 °C
304/L/H 8000 193 17.2 17.8 18.4 16.2 21.5 500 720

Grade Specification Comparison

Table 4. Approximate Grade specifications for 304-grade stainless steel

Grade UNS No Old British Euronorm Swedish SS Japanese JIS
BS En No Name
304 S30400 304S31 58E 1.4301 X5CrNi18-10 2332 SUS 304
304L S30403 304S11 - 1.4306 X2CrNi19-11 2352 SUS 304L
304H S30409 304S51 - 1.4948 X6CrNi18-11 - -

These comparisons are approximate only. The list is intended as a comparison of functionally similar materials, not as a schedule of contractual equivalents. If exact equivalents are needed original specifications must be consulted.

Possible Alternative Grades

Table 5. Possible alternative grades to 304-grade stainless steel

Grade Why it might be chosen instead of 304
301L A higher work hardening rate grade is required for certain roll-formed or stretch formed components.
302HQ Lower work hardening rate is needed for cold forging of screws, bolts, and rivets.
303 Higher machinability needed, and the lower corrosion resistance, formability, and weldability are acceptable.
316 Higher resistance to pitting and crevice corrosion is required, in chloride environments
321 Better resistance to temperatures of around 600-900 °C is needed…321 has higher hot strength.
3CR12 A lower cost is required, and the reduced corrosion resistance and resulting discoloration are acceptable.
430 A lower cost is required, and the reduced corrosion resistance and fabrication characteristics are acceptable.

Corrosion Resistance

Grade 304 stainless steel is excellent in a wide range of atmospheric environments and many corrosive media. It is subject to pitting and crevice corrosion in warm chloride environments, and to stress corrosion cracking above 60 °C (approximate). Grade 304 is considered to be resistant to potable water up to approximately 200 mg/L chlorides at ambient temperatures, reducing to approximately150 mg/L at 60 °C.

Heat Resistance

Grade 304 has good oxidation resistance in intermittent service to 870 °C, and in continuous service to 925 °C. Continuous use of 304 in the 425-860 °C range is not recommended if subsequent aqueous corrosion resistance is important. Grade 304L is more resistant to carbide precipitation and can be heated into this temperature range.

Grade 304H has higher strength at elevated temperatures so is often used for structural and pressure-containing applications at temperatures above 500 °C up to about 800 °C (approximate). 304H will become sensitized in the temperature range of 425-860 °C. Whilst this is not a problem for high-temperature applications, it will result in reduced aqueous corrosion resistance.

Heat Treatment

During Solution Treatment (Annealing) Grade 304 can be heated to 1010-1120 °C and is then cooled rapidly. These grades cannot be hardened by thermal treatment.

Welding

Grade 304 has excellent weldability by all standard fusion methods, both with and without filler metals. AS 1554.6 pre-qualifies welding of 304 with Grade 308 and 304L with 308L rods or electrodes (and with their high silicon equivalents). Heavy welded sections in Grade 304 may require post-weld annealing for maximum corrosion resistance. This is not required for Grade 304L. Grade 321 may also be used as an alternative to 304 if heavy section welding is required and post-weld heat treatment is not possible.

Machining

A "Ugima" improved machinability version of grade 304 is available in bar products. "Ugima" machines significantly better than standard 304 or 304L, giving higher machining rates and lower tool wear in many operations.

Dual Certification

It is common for 304 and 304L to be stocked in "Dual Certified" form, particularly in plate and pipe. These items have chemical and mechanical properties complying with both 304 and 304L specifications. Such dual certified product does not meet 304H specifications and may be unacceptable for high-temperature applications.

Typical Applications

  • Food processing equipment, particularly in beer brewing, milk processing & winemaking
  • Kitchen benches, sinks, troughs, equipment and appliances
  • Architectural paneling, railings & trim
  • Chemical containers, including for transport
  • Heat Exchangers
  • Woven or welded screens for mining, quarrying & water filtration
  • Threaded fasteners
  • Springs

This article was updated on 19th August, 2019.

Comments

  1. Mahmoud Ellithy Mahmoud Ellithy Egypt says:

    I want to know about companies producing SS304 tanks and their offers and how to contact them ....?

    • Amos Stitham Amos Stitham United States says:

      IBI/Global Power
      Engineered-Manufactured-Delivered
      Caldwell, ID
      93716

      (208) 459-6077

      Toll Free: 1 (800) 497-8251

  2. Thanh Tran Thanh Tran United Kingdom says:

    I would like to know 316 and 304 which one is more expensive? or higher quality?

    • Vinay Kumar N Vinay Kumar N India says:

      316 is higher.

      • ugeshkumar s ugeshkumar s India says:

        i want to know list of ss materials and cost

  3. Asrul Aizzad Asrul Aizzad Malaysia says:

    I want to know TIG welding parameter for 304

  4. Musthafa Ismail Musthafa Ismail India says:

    Corrosion Resistance
    Excellent in a wide range of atmospheric environments and many corrosive media. Subject to pitting and crevice corrosion in warm chloride environments, and to stress corrosion cracking above about 60°C. Considered resistant to potable water with up to about 200mg/L chlorides at ambient temperatures, reducing to about 150mg/L at 60°C.

    Pitting and crevice corrosion at what temperature. Please specify.

    • Luis Camargo Luis Camargo Canada says:

      SS304/316/321 are not resistant materials for chloride stress corrosion cracking -these materials fail under conditions (50 ppm of chloride, 60 C and 10 atm pressure)

  5. Brigitta Roselie Brigitta Roselie Indonesia says:

    I want to know how can I find the most updating prices for sus304 in kg (is there any web site)

  6. Tyrone Dunn Tyrone Dunn South Africa says:

    I would like to know if it is acceptable to heat 304 stainless in order to create formswept bends on 6 mm thick angle iron without distorting its metalic properties or reducing its corrosiveness in high humidity coastal areas.

  7. Barry Patterson Barry Patterson United States says:

    Is 304 suitable for a 6" flue pipe from a small coal stove in a hunting camp?

  8. T Arai T Arai United States says:

    Which grade would be best for making an exhaust system for a automobile (specifically a VW Vanagon)? I have seen 304 used, but was thinking that 304H or 316 would be better. Would those grades be available in the required pipe sizes? What would be the trade offs? Strength? Longevity?

    • steve miller steve miller United States says:

      304 and 316 are very expensive and can be overkill in the exhaust application.  Try Cromgard 18-1.  Just Google Cromgard and the company pops up.  Its used a lot in the automotive industry for exhausted systems because of resistance to corrosion and low cost.

    • ihsan durani ihsan durani Islamic Republic of Pakistan says:

      Now a days weight reduction is important goal for automobile applications. so you must use a metal which satisfied the customer and company. 304 and 316 are very high weight and also are costly..............

  9. ugeshkumar s ugeshkumar s India says:

    what is moulding and casting difference between them

    • ihsan durani ihsan durani Islamic Republic of Pakistan says:

      molding is a process of mold making for costing any shape but casting belong to   a process  in which specific shape is given to the materials by using mold. the molten metal is pored into the mold for casting parts..........

  10. Yang Fuqiang Yang Fuqiang People's Republic of China says:

    i want to the elastic moduls of 304 stainless steel at -100~100℃

  11. Kian Farzaneh Kian Farzaneh United States says:

    Is this steel good for making knives?

    • Gary Towne Gary Towne United States says:

      No, because it is relatively soft. It would need frequent sharpening. 440C is normally considered best because it has the highest hardness of all common stainless steels.

    • Dimitrios Mang Dimitrios Mang Greece says:

      The most everyday use of stainless steel is obviously in cutlery. Very cheap cutlery is made  out  of  grades  409  and  430,  with  the  finest  Sheffield  cutlery  using  specially produced 410 and 420 for the knives and grade 304 (18/8 stainless, 18% chromium 8%  nickel)  for  the  spoons  and  forks.

  12. Tuan Tran Tuan Tran United States says:

    Is stainless steel 304 RoHS compliant?

  13. Manoocher Mohebi Manoocher Mohebi Romania says:

    hello
    I want the best suggestion process(whit designing for deep drawing) of cup stainless steel(304) the following data
    outer diameter 49.8 mm
    wall thickness 0.8~1mm
    length  65mm
    r= 5~5.5 mm

  14. Richard Panfil Richard Panfil United States says:

    Does hardness of 304 sheet and angle differ? I am punching 304 SS 3" angle and am bending and deformiing the punch after one use. The punch and die is rated up to 1/4" 304 annealed.

  15. Mark Nels Mark Nels United States says:

    I have a beam, 12-3/4” x 24” that’s spanning 48’.  How much weight is safe in the middle of the span?
    Also, I have a hoist trolley that has a 1-1/4” steel rod that connects the 2 halves of the trolley. The 1-1/4” rod is only long enough  (it’s total length is 9-1/2”) for a 5-1/2” beam.  I need to get a longer rod.  17” will do for a 12-3/4” flange.  I need to drill holes in the ends for cotter pins.  What type of steel do I need and should I worry about the longer length giving problems and bending?  The trolley is rated for 3 tons.
    Found a 304 stainless steel 1-1/4” rod on Ebay.  Would that work for strength?  Can I drill it for the cotter pins?

  16. DHANANJAY KUMAR DHANANJAY KUMAR India says:

    what is the range of bhn no. of ss 304

  17. DHANANJAY KUMAR DHANANJAY KUMAR India says:

    if the value of brinell hardness 187 and second brinell hardness  value is 245 then what is comparision between both

  18. Michael Rederstorf Michael Rederstorf United States says:

    Is it easier to machine 304SS if heat treated and cooled at a certain rate?

  19. arsul iman arsul iman Malaysia says:

    hi. i would like to ask, as for 304L what's the range for the best PWHT and whats the soaking time for it? im using a 9mm thickness.

  20. ahmed omer ahmed omer Saudi Arabia says:

    what is the Heat Range For 304 ?

    • Sachi Jangra Sachi Jangra India says:

      grade 304 stainless steel possesses “good oxidation resistance in intermittent service to 870 °C and in continuous service to 925 °C.” However, they warn that “continuous use of 304 in the 425-860 °C range is not recommended if subsequent aqueous corrosion resistance is important.”

      In other words, you can expose grade 304 alloy steel to temperatures of up to 1,598 °F for short periods of time without ill effect, and for extended periods of time in temperatures of up to 1,697 °F. However, this can compromise the corrosion resistance of the metal, making it more susceptible to corrosion damage from exposure to moisture.

      As noted in 304 stainless steel, the alloy reaches its melting point at the 2,550 °F – 2,650 °F (1399 °C – 1454 °C) range. Naturally, the closer the steel is to its melting point, the more tensile strength it loses.

  21. Ed Avanesian Ed Avanesian United States says:

    is stainless steel 304 okay for liquid paraffin conveying?

  22. Ed Avanesian Ed Avanesian United States says:

    is stainless steel 304 okay for liquid paraffin conveying?

  23. Dell Delilah Dell Delilah Malaysia says:

    Hello,
    can i know what is the best coating type or product which is used for stainless steel SUS 304. Specification coating guarantees for 30 years which is used for building.

  24. Claudio André Claudio André Brazil says:

    Hello, I want to use 304 but the yield strength is really low, can I forge to gain resistance? I have a graph showing a area reduction of 40% and increase 2 times the resistance. Is it possible?

  25. Matt Shelson Matt Shelson United States says:

    I have a spool of T304ss .008 or 32G, wonder if you would know if this is usable in the vaping industry. Building coils that are heated. Some devices can also control the temerature of heating. Also states 890-H and curious what this pertains to? Any information is appereciated. most commonly 316L is used if this helps. I ponder the differences in corrosion or oxidation if any as well.

  26. Anatoly Skirda Anatoly Skirda United States says:

    Is 304 ss RoHS compliant?

  27. mari vijayan mari vijayan India says:

    In ss304,what is mean by 3,0,4. I know its austenitic.... But why we are call them 300 series....how its named???? Any get the answer reply me frds....

  28. J S Dwivedi J S Dwivedi India says:

    WHAT IS 304 Q.Please tell the advantages of using 304 Q over 304.

  29. bhavik adajaniya bhavik adajaniya India says:

    i want to know some property of stainless steel grade 304. properties like

    1. minimum yield stress
    2. minimum tensile strength
    3. effective yield stress
    4. effective tensile strength
    5. weight per unit volume
    6. coefficient of thermal expansion
    7. Poisson's ratio
    8. modulus of elasticity

  30. Akshay Patel Akshay Patel India says:

    what is the dielectric strength of 304 steel

  31. Muthu Mmr Muthu Mmr India says:

    I want to know about welding parameters for SS 304

  32. Mohamed Romieh Mohamed Romieh Egypt says:

    where can i find a test report for raw materiel S.S 304 wire mesh 3mm thick ?

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of AZoM.com.

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