Stainless Steel Pipes & Tubes
304 Stainless Steel Pipes & Tubes
One of the most versatile and commonly used stainless steels on the market, Grade 304 stainless steel is the most standard used alloy of this type. Essentially, Grade 304 is an austenitic chromium alloy which is also known as an "18/8" stainless as the make-up of the steel is 18% chromium and 8% nickel. The chromium content promotes the material's considerable resistance to the effects of corrosion and oxidation. The stainless steel alloy resists most oxidizing acids and will withstand ordinary rusting though this does not mean that the steel will not tarnish over time. The steel needs to be cold worked to generate higher tensile strength. For stainless steel sections which are welded heavily, post-weld annealing may be necessary to provide maximum corrosive resistance.
304 Stainless Steel Pipes and Tubes Product Range
304 Stainless Steel Pipes and Tubes Specifications: ASTM A/ASME SA213/A249/A269/A312/A358 CL. I to V ASTM A789/A790
304 Stainless Steel Pipes and Tubes Sizes (Seamless): 1/2” NB - 16” NB
304 Stainless Steel Pipes and Tubes Sizes (ERW): 1/2” NB - 24” NB
304 Stainless Steel Pipes and Tubes Sizes (EFW): 6” NB - 100” NB
304 Stainless Steel Pipes and Tubes Wall Thickness available:
Schedule 5S - Schedule XXS (heavier on request)
NACE MR0175, H2 SERVICE, OXYGEN SERVICE, CRYO SERVICE, etc.
304 Stainless Steel Pipes and Tubes Dimensions:All Pipes is manufactured and inspected/tested to the relevant standards including ASTM, ASME and API etc.
Type 304 Stainless Steel has excellent welding and deep drawing characteristics - it is easy to fabricate, easy to clean and aesthetically pleasing to the eye. The steel is common throughout industry particularly in food processing as the material is not susceptible to corrosion from acids found in common foodstuffs. As a consequence, such steel is ideal for items such as sinks, work surfaces, preparation areas and refrigerators. It is also a perfect material for use in the pharmaceutical industry for environments such as clean rooms. Grade 304 can also be found in heat exchangers, chemical containers, pipelines and throughout the brewing industry. It can be used as a fabricated material where high temperature petroleum gases or steam production gases are stored such as pressure vessels. It can even be found extensively in the construction industry where the material is used for cosmetic purposes such as building fascias. 304 & 304L plate and pipes have similar properties and in certain cases are stocked with Dual Certification, where it is concluded that each item has properties and a composition which comply with both steel types. Grade 304H cannot be included in this equation due to the steel's higher carbon content which is intended for use in elevated temperature applications. |
304 Stainless Steel Pipes and Tubes Composition
Typical compositional ranges for grade 304 stainless steels are given in table 1.
Table 1. Composition ranges for 304 grade stainless steel
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N | |
|---|---|---|---|---|---|---|---|---|---|---|
| 304 | min. | - | - | - | - | - | 18.0 | - | 8.0 | - |
| max. | 0.08 | 2.0 | 0.75 | 0.045 | 0.030 | 20.0 | 10.5 | 0.10 | ||
| 304L | min. | - | - | - | - | - | 18.0 | - | 8.0 | - |
| max. | 0.030 | 2.0 | 0.75 | 0.045 | 0.030 | 20.0 | 12.0 | 0.10 | ||
| 304H | min. | 0.04 | - | - | - | - | 18.0 | - | 8.0 | - |
| max. | 0.10 | 2.0 | 0.75 | 0.045 | 0.030 | 20.0 | 10.5 | |||
304 Stainless Steel Pipes and Tubes Mechanical Properties
Typical mechanical properties for grade 304 stainless steels are given in table 2.
| Grade | Tensile Strength (MPa) min |
YieldStrength 0.2% Proof (MPa) min |
Elongation (%in 50mm) 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 has a requirement for a grain size of ASTM No 7 or coarser. | |||||
304 Stainless Steel Pipes and Tubes Physical PropertiesTypical physical properties for annealed grade 304 stainless steels are given in table 3.
Table 3. Physical properties of 304 grade stainless steel in the annealed condition
| Grade | Density (kg/m3) | Elastic Modulus (GPa) | Mean Coefficient of Thermal Expansion (m/m/0C) | Thermal Conductivity (W/m.K) | Specific Heat 0-1000C (J/kg.K) | Electrical Resistivity (n.m) | |||
|---|---|---|---|---|---|---|---|---|---|
| 0-1000C | 0-3150C | 0-5380C | at 1000C | at 5000C | |||||
| 304/L/H | 8000 | 193 | 17.2 | 17.8 | 18.4 | 16.2 | 21.5 | 500 | 720 |
304 Stainless Steel Pipes and Tubes Grade Specification ComparisonApproximate grade comparisons for 304 stainless steels are given in table 4.
Table 4. 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. |
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304 Stainless Steel Pipes and Tubes 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 600C. Considered resistant to potable water with up to about 200mg/L chlorides at ambient temperatures, reducing to about 150mg/L at 600C. |
304 Stainless Steel Pipes and Tubes Heat ResistanceGood oxidation resistance in intermittent service to 8700C and in continuous service to 9250C. Continuous use of 304 in the 425-8600C range is not recommended if subsequent aqueous corrosion resistance is important. Grade 304L is more resistant to carbide precipitation and can be heated into the above temperature range. Grade 304H has higher strength at elevated temperatures so is often used for structural and pressure-containing applications at temperatures above about 5000C and up to about 8000C. 304H will become sensitised in the temperature range of 425-8600C; this is not a problem for high temperature applications, but will result in reduced aqueous corrosion resistance. |
304 Stainless Steel Pipes and Tubes Heat Treatment| Solution Treatment (Annealing) - Heat to 1010-11200C and cool rapidly. These grades cannot be hardened by thermaltreatment. |