304H stainless steel pipe is a high-carbon variant of 304 stainless steel, designed for high-temperature applications. It provides enhanced strength and corrosion resistance, making it ideal for industries like power generation, chemical processing, and heat exchangers.
Stainless steel is a versatile and widely used material in various industries, and one of its popular grades is 304 stainless steel. The “304” designation refers to its composition, which includes a significant amount of chromium and nickel, making it an austenitic stainless steel with excellent corrosion resistance, durability, and versatility.
What is the grade of SS304H?
SS 304H is a high-carbon variant of 304 stainless steel, designed for high-temperature applications. It is classified under the Austenitic Stainless Steel category and follows international standards such as:
Standards & Specifications for SS 304H
| Standard | Designation |
| ASTM | ASTM A240, ASTM A312, ASTM A213, ASTM A276 |
| ASME | ASME SA240, SA312, SA213, SA276 |
| EN (European) | EN 1.4948 |
| UNS (Unified Numbering System) | UNS S30409 |
| JIS (Japanese) | JIS SUS 304H |
| DIN (German) | X6CrNi18-10 |
Main Features of SS 304H
✅ Higher Carbon Content → Improves strength at high temperatures.
✅ Better Creep Resistance → Suitable for applications above 1000°F (538°C).
✅ Good Weldability → Can be welded using standard techniques but may require post-weld heat treatment.
✅ Excellent Corrosion Resistance → Similar to 304 but slightly less than 304L due to higher carbon.
What is H grade stainless steel?
“H” grade stainless steel refers to high-carbon variants of standard stainless steel grades. These grades are specifically designed for high-temperature applications, where increased strength and creep resistance are required. The higher carbon content (typically 0.04% – 0.10%) enhances mechanical properties at elevated temperatures.
Common “H” Grade Stainless Steels & Their Differences
| Grade | Base Grade | Carbon Content (%) | Application |
| 304H | 304 | 0.04 – 0.10 | Boilers, heat exchangers, power plants |
| 316H | 316 | 0.04 – 0.10 | High-temperature chemical processing, marine environments |
| 321H | 321 | 0.04 – 0.10 | Aerospace, thermal processing, exhaust systems |
| 347H | 347 | 0.04 – 0.10 | High-temperature pipelines, pressure vessels |
Key Features of H Grade Stainless Steel
Higher Carbon Content → Increases strength and creep resistance at elevated temperatures.
Improved High-Temperature Performance → Ideal for applications above 1000°F (538°C).
Slightly Reduced Corrosion Resistance → Higher carbon may slightly reduce corrosion resistance compared to the low-carbon (“L”) grades.
Comparison: H vs. L vs. Standard Grades
| Grade | Carbon Content (%) | Best Use Case |
| Standard (e.g., 304, 316) | ≤ 0.08 | General-purpose corrosion resistance |
| L (e.g., 304L, 316L) | ≤ 0.03 | Improved weldability and corrosion resistance |
| H (e.g., 304H, 316H) | 0.04 – 0.10 | High-temperature strength and durability |
304H Stainless Steel Pipe Specification
| Processing Method | Seamless and Welded |
| Size Range | 1/8” – 30” / DN6 – 750 |
| Thickness Schedule | SCH 10S- SCH 160, XXS |
| Length | 6m or 12 m or Random |
| Standard | ASME B36.19 |
| Surface Treatment | Polish , Mirror , Epoxy Powder FBE, 2PE, 3PE Coating |
| Material Grade | ASTM A312 TP304/304L/304H, 316/316L, 310S, 317, 347, 904L, S32205, S31803, 32750, 32760, S32550 |
304L/304H / 304 Stainless Steel Composition
| CHEMICAL | LIMITS | C | Mn | P | S | Si | Ni | Cr | Mo | N |
| ASTM A312 TP304 | MIN | 8.00 | 18.00 | |||||||
| MAX | 0.08 | 2.00 | 0.05 | 0.03 | 1.00 | 11.00 | 20.00 | |||
| ASTM A312 TP304L | MIN | 8.00 | 18.00 | |||||||
| MAX | 0.035 | 2.00 | 0.045 | 0.030 | 1.00 | 13.00 | 20.00 | |||
| ASTM A312 TP304H | MIN | 0.040 | 8.00 | 18.00 | ||||||
| MAX | 0.100 | 2.00 | 0.045 | 0.030 | 1.00 | 11.00 | 20.00 |
Stainless Steel 304 / 304L / 304H Pipes Mechanical Properties
| MATERIAL | T.S (MPA) | Y.S (MPA) | EL % | R/A % |
| ASTM A312 TP304 | 515min | 205 min | 35 min | 50 min |
| ASTM A312 TP304L | 485 min | 170 min | 35 min | 50 min |
| ASTM A312 TP304H | 515min | 205min | 35 min | 50 min |
304H Stainless Steel Pipes and Tubes Physical Properties
| 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 |
Equivalent grades of AISI 304h Pipe
| GRADE | UNS | WERKSTOFF NR. | JIS | AFNOR | BS | GOST | EN | SS |
| USA | GERMAN | JAPAN | RUSSIAN | BRITISH | RUSSIAN | EUROPE | SWEDISH | |
| ASTM A312 304H | S30409 | 1.4948 | SUS 304H | – | 304S11 | – | X5CrNi18-10 | 2332 |
What is the difference between 304 and 304H?
The primary difference between 304 stainless steel and 304H stainless steel lies in their carbon content, which affects their strength, temperature resistance, and specific applications.
| Property | 304 Stainless Steel | 304H Stainless Steel |
| Carbon Content | ≤ 0.08% | 0.04% – 0.10% |
| High-Temperature Strength | Moderate | Higher due to increased carbon |
| Temperature Resistance | Suitable up to ~800°F (427°C) | Performs better in temperatures above 1000°F (538°C) |
| Corrosion Resistance | Excellent | Slightly better at high temperatures |
| Weldability | Excellent, minimal carbide precipitation | Good, but may require post-weld heat treatment in some cases |
| Applications | General-purpose applications (food processing, architecture, medical) | High-temperature environments (boilers, heat exchangers, power plants) |
Which One Should You Choose?
If your application requires exposure to high temperatures (above 1000°F or 538°C), 304H is the better choice due to its increased strength.
For general-purpose corrosion resistance and room-temperature applications, standard 304 stainless steel is sufficient and more commonly used.
304 Stainless Steel Pipe: Heat Resistance
304 stainless steel is an austenitic stainless steel known for its excellent corrosion resistance, durability, and moderate heat resistance. It is commonly used in high-temperature environments but has certain limitations depending on the operating conditions.
Maximum Operating Temperatures of 304 Stainless Steel
| Condition | Maximum Temperature | Notes |
| Continuous service (oxidizing environment) | 870°C (1598°F) | Can resist oxidation but prolonged exposure may weaken mechanical properties. |
| Short-term exposure (oxidizing environment) | 925°C (1697°F) | Can tolerate short bursts of high temperature but may experience grain growth. |
| Maximum temperature (non-oxidizing environment) | ~1000°C (1832°F) | In vacuum or controlled atmosphere, it can withstand even higher temperatures. |
304 Stainless Steel Pipe Properties at High Temperatures
Creep Strength:
At 600°C (1112°F) and above, the material starts losing its strength.
304H stainless steel, a high-carbon variant, is recommended for better creep resistance.
Oxidation resistance
Below 870°C, 304 stainless steel can maintain good oxidation resistance, but if exposed to high-temperature oxidation environment for a long time, an oxide layer may be formed, affecting the service life.
Carburization resistance
In high-temperature environments, 304 stainless steel may reduce corrosion resistance due to carbide precipitation, especially intergranular corrosion is prone to occur between 450-850°C.
Mechanical property changes:
Above 600°C, the strength of 304 stainless steel will gradually decrease, which may affect its load-bearing capacity.
When used in long-term high-temperature environments, it may be necessary to select 304H stainless steel (high carbon version) to improve creep resistance and high-temperature strength.
304H Stainless Steel Pipe: Types of Packaging
Proper packaging of 304H stainless steel pipes is crucial to prevent damage during transportation and storage. The packaging method depends on factors such as pipe size, quantity, transportation mode, and customer requirements.
1. Bundling with Steel Straps
2. Wooden Cases or Crates
3. Plastic Wrapping or Shrink Film
4. End Caps & Protective Covers
5.Seaworthy Packing for Export
Choosing the Right Packaging Method
| Packaging Type | Best for | Protection Level | Cost |
| Bundling with Steel Straps | Large-diameter pipes, bulk shipments | Moderate | Low |
| Wooden Cases/Crates | Export, thin-walled pipes, precision tubes | High | High |
| Plastic Wrapping | Short-distance transport, indoor storage | Low to Medium | Low |
| End Caps | Seamless pipes, threaded pipes | Medium | Low |
| Seaworthy Packing | International shipping | Very High | High |
Stainless Steel Pipe Dimension
304H stainless steel pipe is a general purpose stainless steel pipe used in different industries. Its diameter ranges from 1/8” to 30”, and thickness ranges from SCH 5S to SCH 80S.
| Stainless Steel Pipe (ASME B 36.19M) | ||||||||||
| Nominal Size | OD | Sch5s | Sch10s | Sch40s | Sch80s | |||||
| DN | NPS | 0 | T | kg/m | T | kg/m | T | kg/m | T | kg/m |
| 6 | 1/8 | 10.3 | 1.24 | 0.28 | 1.73 | 0.37 | 2.41 | 0.47 | ||
| 8 | 1/4 | 13.7 | 1.65 | 0.49 | 2.24 | 0.63 | 3.02 | 0.8 | ||
| 10 | 3/8 | 17.1 | 1.65 | 0.63 | 2.31 | 0.84 | 3.2 | 1.1 | ||
| 15 | 1/2 | 21.3 | 1.65 | 0.82 | 2.11 | 1 | 2.77 | 1.27 | 3.73 | 1.62 |
| 20 | 3/4 | 26.7 | 1.65 | 1.04 | 2.11 | 1.28 | 2.87 | 1.69 | 3.91 | 2.2 |
| 25 | 1 | 33.4 | 1.65 | 1.33 | 2.77 | 2.09 | 3.38 | 2.5 | 4.55 | 3.24 |
| 32 | 1 1/4 | 42.2 | 1.65 | 1.68 | 2.77 | 2.7 | 3.56 | 3.39 | 4.85 | 4.47 |
| 40 | 1 1/2 | 48.3 | 1.65 | 1.95 | 2.77 | 3.11 | 3.68 | 4.05 | 5.08 | 5.41 |
| 50 | 2 | 60.3 | 1.65 | 2.44 | 2.77 | 3.93 | 3.91 | 5.44 | 5.54 | 7.48 |
| 65 | 2 1/2 | 73.0 | 2.11 | 3.77 | 3.05 | 5.26 | 5.16 | 8.63 | 7.01 | 11.41 |
| 80 | 3 | 88.9 | 2.11 | 4.6 | 3.05 | 6.45 | 5.49 | 11.29 | 7.62 | 15.27 |
| 90 | 31/2 | 101.6 | 2.11 | 5.29 | 3.05 | 7.4 | 5.74 | 13.57 | 8.08 | 18.63 |
| 100 | 4 | 114.3 | 2.11 | 5.96 | 3.05 | 8.36 | 6.02 | 16.07 | 8.56 | 22.32 |
| 125 | 5 | 141.3 | 2.77 | 9.67 | 3.4 | 11.57 | 6.55 | 21.77 | 9.53 | 30.97 |
| 150 | 6 | 168.3 | 2.77 | 11.55 | 3.4 | 13.48 | 7.11 | 28.26 | 10.97 | 42.56 |
| 200 | 8 | 219.1 | 2.77 | 15.09 | 3.76 | 19.96 | 8.18 | 42.55 | 12.7 | 64.64 |
| 250 | 10 | 273.1 | 3.4 | 23.08 | 4.19 | 27.78 | 9.27 | 60.31 | 12.7 | 96.01 |
| 300 | 12 | 323.9 | 3.96 | 31.89 | 4.57 | 36 | 9.53 | 73.88 | 12.7 | 132.08 |
| 350 | 14 | 355.6 | 3.96 | 35.06 | 4.78 | 41.3 | ||||
| 400 | 16 | 406.4 | 4.19 | 42.41 | 4.78 | 47.29 | ||||
| 450 | 18 | 457.2 | 4.19 | 47.77 | 4.78 | 53.26 | ||||
| 500 | 20 | 508 | 4.78 | 60.46 | 5.54 | 68.61 | ||||
| 550 | 22 | 558.8 | 4.78 | 66.57 | 5.54 | 75.53 | ||||
| 600 | 24 | 609.6 | 5.54 | 84.16 | 6.35 | 94.45 | ||||
| 750 | 30 | 762 | 6.35 | 120.72 | 7.92 | 147.36 | ||||
Permitted Tolerance in Wall Thickness
| Tolerance,%from Nominal | ||
| NPS Designator | Over(+) | Under (-) |
| 1/8 to 21/2 incl.,all t/D ratios | 20.0 | 12.5 |
| 3 to 18 incl.,t/D up to 5% incl. | 22.5 | 12.5 |
| 3 to 18 incl.,t/D>5% | 15.0 | 12.5 |
| 20 and larger,weldedall t/D ratios | 17.5 | 12.5 |
| 20 and larger,seamlesst/D up to 5% incl. | 22.5 | 12.5 |
| 20 and larger,seamlesst/D>5% | 15.0 | 12.5 |
| t = Nominal Wall ThicknessD = Ordered Outside Diameter | ||
What is the advantage of 304 stainless steel?
1. Excellent Corrosion Resistance
2. High Strength and Durability
3. Good Weldability and Fabrication
4. Hygienic and Easy to Clean
5. Heat and Temperature Resistance
6. Aesthetic Appeal
7. Cost-Effective
You can get an offer for products in below material forms:
-Pipe and Tube (EN 10216-5, ASTM A213, ASTM A249, A312, A790,)
-Forged Fitting and Flange (ASTM A182 , ASTM A105,ASTM B564 )
-Butt Weld Fittings (ASTM A234, ASTM A403,ASTM A815)
-Round bar , Billet (ASTM A276, ASTM A479)
– Plate, Sheet, Strip(ASTM A240, EN 10028-7, A480)
-Bolting, Nuts（ASTM A193, A194, A320）
304H Stainless Steel Pipe Exported Countries
We Export 304H Stainless Steel Pipe to Saudi Arabia, United Arab Emirates, Qatar, Bahrain, Oman, Kuwait, Turkey, Egypt, Yemen , Syria, Jordan, Cyprus, Singapore, Malaysia, Indonesia, Thailand, Vietnam, South Korea, Japan, Sri Lanka, Maldives, Bangladesh, Cambodia, Argentina, Bolivia, Brazil, Venezuela, Colombia, Ecuador, Guyana, Paraguay, Uruguay, United States Of America, Canada, Mexico, Panama, Jamaica, Bahamas, Denmark, Norway, Germany, France,Italy, United Kingdom, Spain, Belgium, Greece, Czech Republic, Portugal, Hungary, Albania, Austria, Finland, Ireland, Croatia, Malta, Nigeria, Algeria, Angola, South Africa, Libya, Egypt, Sudan, Europe, Africa, Asia, North America, South America, Middle East.etc