Chemical Composition of Stainless Steel Buttweld Fittings
This document provides a detailed overview of the chemical composition and mechanical properties of various grades of stainless steel buttweld fittings, which are widely used in piping systems for industrial applications, including chemical processing, oil & gas, and power generation.
🔬 Chemical Composition of Stainless Steel Buttweld Fittings:
Each stainless steel grade listed includes the percentage range (or maximum limit) of essential elements that define its corrosion resistance, mechanical strength, and weldability. Key alloying elements include:
- Carbon (C): Affects hardness and strength. Lower carbon improves weldability (e.g., 304L, 316L).
- Manganese (Mn), Silicon (Si), Phosphorus (P), Sulfur (S): Assist in deoxidization and machinability but are controlled due to their effects on corrosion resistance.
- Chromium (Cr): Provides corrosion resistance (ranges from 11.5% in 410 to 30% in 446).
- Nickel (Ni): Improves toughness and corrosion resistance (higher in austenitic steels like 904L).
- Molybdenum (Mo): Enhances pitting resistance (notable in 316, 317, 904L).
- Nitrogen (N): Improves mechanical strength and corrosion resistance (present in duplex and high-performance alloys).
- Niobium (Cb): Used for stabilization in grades like 347.
Examples:
SS 304/304L/304H: General-purpose austenitic stainless steels with varying carbon levels for different applications.
SS 316/316L/316Ti: Molybdenum-bearing grades for enhanced corrosion resistance.
SS 310/310S: High-temperature steels with high Cr and Ni content.
SS 904L: Super austenitic stainless steel with high Mo and Cu for aggressive environments.
⚙️ Mechanical Properties of Stainless Steel Buttweld Fittings:
- The mechanical section lists the key physical properties that influence performance under stress and temperature, including:
- Density: Ranges from 7.5 g/cm³ (SS 446) to 8.0 g/cm³ (most austenitic grades).
- Melting Point: Typically ranges between 1350°C to 1510°C, depending on grade.
- Tensile Strength: Most austenitic stainless steels have a tensile strength of ~75,000 psi (515 MPa).
- Yield Strength (0.2% Offset): Approximately 30,000 psi (205 MPa) in most grades.
- Elongation (%): Indicator of ductility; generally around 35-40%, except SS 446 which is lower at 20%.
🧪 Applications of Stainless Steel Buttweld Fittings:
- These fittings are selected based on chemical and mechanical properties suitable for specific conditions such as:
High temperature (e.g., SS 310, 446)
High corrosion environments (e.g., SS 316, 904L)
Welded structures (e.g., low-carbon versions like 304L, 316L)
Chloride environments (e.g., 317L, 904L)
Chemical Composition of Stainless Steel Buttweld Fittings
| Grade | C | Mn | Si | P | S | Cr | Ni |
|---|---|---|---|---|---|---|---|
| SS 304 | 0.08 max | 2 max | 0.75 max | 0.045 max | 0.030 max | 18 – 20 | 8 – 11 |
| Grade | C | Mn | Si | P | S | Cr | Ni |
|---|---|---|---|---|---|---|---|
| SS 304L | 0.035 max | 2.0 max | 1.0 max | 0.045 max | 0.03 max | 18 – 20 | 8 – 13 |
| Grade | C | Si | P | Mn | Mo | Ni | S | Cr | N |
|---|---|---|---|---|---|---|---|---|---|
| SS 304H | 0.10 max | 0.75 max | 0.045 max | 2 max | – | 8 – 10.5 | 0.03 max | 18 – 20 | – |
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | Fe |
|---|---|---|---|---|---|---|---|---|---|
| SS 310S | 0.08 max | 2.0 max | 1.00 max | 0.045 max | 0.030 max | 24.00 – 26.00 | 0.75 max | 19.00 – 21.00 | 53.095 min |
| SS 310 | 0.015 max | 2.0 max | 0.15 max | 0.020 max | 0.015 max | 24.00 – 26.00 | 0.10 max | 19.00 – 21.00 | 54.7 min |
| Grade | C | Mn | P | Si | Ni | Fe | S | Cr | Mo |
|---|---|---|---|---|---|---|---|---|---|
| SS 316L | 0.035 max | 2.0 max | 0.045 max | 1.0 max | 10.00 – 14.00 | 68.89 min | 0.030 max | 16.00 – 18.00 | 2.00 – 3.00 |
| SS 316 | 0.08 max | 2.0 max | 0.045 max | 1.0 max | 11.00 – 14.00 | 67.845 min | 0.030 max | 16.00 – 18.00 | 2.00 – 3.00 |
| Grade | C | Mn | P | S | Si | Cr | Ni | Mo | Fe |
|---|---|---|---|---|---|---|---|---|---|
| SS 316Ti | 0.08 max | 2.0 max | 0.045 max | 0.030 max | 0.75 max | 16.00 – 18.00 | 10.00 – 14.00 | 2.00 – 3.00 | 68.395 min |
| Grade | C | Si | Mn | P | Ni | Fe | S | Cr | Mo |
|---|---|---|---|---|---|---|---|---|---|
| SS 317 | 0.08 max | 1.0 max | 2.0 max | 0.045 max | 11.00 – 15.00 | 57.845 min | 0.030 max | 18.00 – 20.00 | 3.00 – 4.00 |
| Grade | C | Mn | S | Cr | Si | P | Mo | Ni | Fe |
|---|---|---|---|---|---|---|---|---|---|
| SS 317L | 0.035 max | 2.0 max | 0.030 max | 18.00 – 20.00 | 1.0 max | 0.045 max | 3.00 – 4.00 | 11.00 – 15.00 | 57.89 min |
| Grade | C | Mn | Cr | Cb | Si | P | S | Ni | Fe |
|---|---|---|---|---|---|---|---|---|---|
| SS 347H | 0.04 – 0.10 | 2.0 max | 17.00 – 19.00 | 8xC – 1.10 | 1.0 max | 0.045 max | 0.030 max | 9.0 -13.0 | 63.72 min |
| SS 347 | 0.08 max | 2.0 max | 17.00 – 20.00 | 10xC – 1.10 | 1.0 max | 0.045 max | 0.030 max | 9.00 – 13.00 | 62.74 min |
| Grade | C | P | S | Mn | Si | Cr | Mo | Ni | N | |
|---|---|---|---|---|---|---|---|---|---|---|
| 410 | min. | – | – | – | – | – | 11.5 | – | – | – |
| max. | 0.15 | 0.040 | 0.030 | 1.0 | 1.00 | 13.5 | – | 0.75 | – | |
| Grade | C | Mn | S | Cr | Mo | Si | P | Ni | N | Fe |
|---|---|---|---|---|---|---|---|---|---|---|
| SS 446 | 0.2 max | 1.5 max | 0.030 max | 23 – 30 | – | 0.75 max | 0.04 max | 0.50 max | 0.10 – 0.25 | Balance |
| Grade | C | Mn | P | S | Si | Cr | MO | Ni | N | |
|---|---|---|---|---|---|---|---|---|---|---|
| 446 | Min | – | – | – | – | – | 23.00 | – | – | 0.10 |
| max | 0.2 | 1.5 | 0.75 | 0.030 | 30.00 | 0.040 | – | 0.50 | 0.25 | – |
| Grade | C | S | Cr | Mn | Si | Ni | Cu | P | Mo |
|---|---|---|---|---|---|---|---|---|---|
| SS 904L | 0.020 max | 0.030 max | 19.00 – 23.00 | 2.00 max | 1.00 max | 23.00 – 28.00 | 1.00 – 2.00 | 0.040 max | 4.00 – 5.00 max |
Mechanical Properties of Stainless Steel Buttweld Fittings
| Grade | Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
|---|---|---|---|---|---|
| 304 | 8.0 g/cm3 | 1400 °C (2550 °F) | Psi – 75000 , MPa – 515 | Psi – 30000 , MPa – 205 | 35 % |
| Grade | Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
|---|---|---|---|---|---|
| 304L | 8.0 g/cm3 | 1400 °C (2550 °F) | Psi – 75000 , MPa – 515 | Psi – 30000 , MPa – 205 | 35 % |
| Grade | Density | Tensile Strength | Melting Point | Yield Strength (0.2%Offset) | Elongation |
|---|---|---|---|---|---|
| 304h | 8.0 g/cm3 | Psi – 75000 , MPa – 515 | 1400 °C (2550 °F) | Psi – 30000 , MPa – 205 | 40 % |
| Grade | Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
|---|---|---|---|---|---|
| 310/310s | 7.9 g/cm3 | 1402 °C (2555 °F) | Psi – 75000 , MPa – 515 | Psi – 30000 , MPa – 205 | 40 % |
| Grade | Melting Point | Density | Elongation | Tensile Strength | Yield Strength (0.2%Offset) |
|---|---|---|---|---|---|
| SS 316L | 1399 °C (2550 °F) | 8.0 g/cm3 | 35 % | Psi – 75000 , MPa – 515 | Psi – 30000 , MPa – 205 |
| SS 316 | 1400 °C (2550 °F) | 8.0 g/cm3 | 35 % | Psi – 75000 , MPa – 515 | Psi – 30000 , MPa – 205 |
| Grade | Density | Tensile Strength | Melting Point | Yield Strength (0.2%Offset) | Elongation |
|---|---|---|---|---|---|
| 316Ti | 8.0 g/cm3 | Psi – 75000 , MPa – 515 | 1399 °C (2550 °F) | Psi – 30000 , MPa – 205 | 35 % |
| Grade | Density | Tensile Strength | Melting Point | Yield Strength (0.2%Offset) | Elongation |
|---|---|---|---|---|---|
| 317 | 7.9 g/cm3 | Psi – 75000 , MPa – 515 | 1400 °C (2550 °F) | Psi – 30000 , MPa – 205 | 35 % |
| Grade | Density | Tensile Strength | Melting Point | Yield Strength (0.2%Offset) | Elongation |
|---|---|---|---|---|---|
| 317L | 7.9 g/cm3 | Psi – 75000 , MPa – 515 | 1400 °C (2550 °F) | Psi – 30000 , MPa – 205 | 35 % |
| Grade | Density | Melting Point | Tensile Strength | Yield Strength (0.2%Offset) | Elongation |
|---|---|---|---|---|---|
| 347/347h | 8.0 g/cm3 | 1454 °C (2650 °F) | Psi – 75000 , MPa – 515 | Psi – 30000 , MPa – 205 | 35 % |
| Grade | Density | Melting Point | Yield Strength (0.2%Offset) | Tensile Strength | Elongation |
|---|---|---|---|---|---|
| 446 | 7.5 g/cm3 | 1510 °C (2750 °F) | Psi – 40,000 , MPa – 275 | Psi – 75,000 , MPa – 485 | 20 % |
| Grade | Density | Tensile Strength | Melting Point | Yield Strength (0.2%Offset) | Elongation |
|---|---|---|---|---|---|
| 446 | 7.5 g/cm3 | Psi – 75,000 , MPa – 485 | 1510 °C (2750 °F) | Psi – 40,000 , MPa – 275 | 20 % |
| Grade | Density | Tensile Strength | Melting Point | Yield Strength (0.2%Offset) | Elongation |
|---|---|---|---|---|---|
| 904L | 7.95 g/cm3 | Psi – 71000 , MPa – 490 | 1350 °C (2460 °F) | Psi – 32000 , MPa – 220 | 35 % |
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Explore moreFAQs - Stainless Steel Buttweld Fittings
SS 304 has 18–20% Cr, 8–11% Ni, with low carbon, manganese, and silicon for corrosion resistance and general-purpose use.
304L has reduced carbon (0.035%) compared to 304 (0.08%), improving weldability and minimizing carbide precipitation in welded structures.
SS 316 offers 75,000 psi tensile strength, 30,000 psi yield strength, 35% elongation, and excellent corrosion resistance with molybdenum content.
SS 310S contains high chromium and nickel, enhancing oxidation resistance, thermal stability, and structural integrity in extreme heat conditions.
SS 446 has 7.5 g/cm³ density and a high melting point of 1510 °C, suitable for elevated temperature applications.
SS 317L has lower carbon (0.035%) than 317 (0.08%), which improves weldability while maintaining similar corrosion and strength performance.
SS 904L has 71,000 psi tensile strength but excels in corrosion resistance due to high nickel, copper, and molybdenum content.
SS 347H includes niobium (Cb) for stabilization against carbide precipitation, making it ideal for high-temperature welded applications.
Titanium stabilizes 316Ti, preventing intergranular corrosion after welding by reducing carbide formation at high heat zones.
SS 310 offers higher elongation and oxidation resistance; SS 446 has lower ductility but higher chromium content for extreme heat.