Seamless Stainless Steel TP316L Tube
Distinguished by its extra-low carbon content (0.03% max) and strategic Molybdenum (2-3%) addition, our TP316L tubing effectively prevents carbide precipitation during welding, eliminating the risk of intergranular corrosion without the need for post-weld annealing. These tubes are indispensable for mission-critical applications in pharmaceutical processing, marine infrastructure, and high-pressure petrochemical systems. Through advanced cold-drawing and precise solution annealing, GZH ensures every tube maintains a stable microstructure and superior surface finish for demanding global industrial needs.
TP316L PREN ≈ 24-26,higher than TP304L PREN ≈ 18
What is a Seamless Stainless Steel TP316L Tube?
TP316L Seamless Stainless Steel Tube is a high-grade, precision-engineered hollow cylinder manufactured from a single, solid billet of stainless steel, completely free of any welded seams. The fundamental seamless construction is essential for guaranteeing maximum structural integrity, superior pressure capability, and consistent, reliable performance without the inherent potential flaws associated with welded joints.
The"316L"designation signifies a low-carbon version of the standard 316 stainless steel. The"L"stands for"Low Carbon,"which is its defining characteristic. This reduced carbon content critically minimizes the risk of carbide precipitation during welding. Carbide precipitation can lead to a phenomenon known as"weld decay,"where localized corrosion occurs in the heat-affected zones of the welds. By mitigating this risk, 316L ensuresexcellent corrosion resistance even after welding, making it an ideal choice for intricate, heavy-gauge welded components and applications where post-weld annealing is not practical. It fully retains the superior general and pitting corrosion resistance of standard 316 due to its crucial molybdenum content.
Key Features and Advantages
Seamless TP316L Stainless Steel Tube offer a powerful combination of benefits that make them invaluable across a broad spectrum of demanding industries, particularly where precision and welding are involved:
Exceptional Post-Weld Corrosion Resistance: The low carbon content is the primary differentiator, virtually eliminating carbide precipitation during welding, thus preventing intergranular corrosion (weld decay) in the heat-affected zones. This is critical for maintaining corrosion resistance in sensitive, welded structures.
Superior General and Pitting Corrosion Resistance: Like standard 316, it offers excellent resistance to a wide range of corrosive media, especially in acidic, alkaline, and chloride-rich environments, due to its molybdenum content.
Enhanced Crevice Corrosion Resistance: The molybdenum further boosts its resistance to pitting and crevice corrosion, making it particularly effective in saline or halogen-containing solutions and applications with tight clearances.
Good High-Temperature Strength: It maintains good strength and creep resistance at elevated temperatures, suitable for many industrial processes, although its maximum service temperature might be slightly lower than 316 for sustained high-temperature mechanical properties due to the lower carbon.
Excellent Formability and Ductility: Offers good ductility and can be readily formed, bent, and manipulated, making it versatile for various precision fabrication needs.
Hygienic and Non-Reactive: Its smooth, non-porous surface and high corrosion resistance make it perfectly suited for applications requiring stringent hygiene standards, such as in medical and food-grade equipment.
Product Specifications and Data
To provide a comprehensive overview of this versatile material, here are the detailed technical specifications and performance data for 316L stainless steel.
Table 1: Chemical Composition of 316L Stainless Steel
The key difference in 316L's composition is its significantly lower carbon content (max 0.03%), while retaining the essential molybdenum for superior corrosion resistance.
| Cr | Ni | Mo | P | S | Mn | Si | C |
| 16.00−18.00 | 10.00−14.00 | 2.00−3.00 | ≤0.045 | ≤0.03 | ≤2.00 | ≤0.75 | ≤0.03 |
Table 2: Typical Mechanical Properties of 316L Stainless Steel
Grade316L offers a good balance of strength and ductility, with a slightly lower tensile and yield strength compared to 316 due to its lower carbon content, but still robust for most demanding applications.
| Property | Value |
| Tensile Strength | 485−690 MPa |
| Yield Strength | ≥170 MPa |
| Elongation | ≥40% |
| Rockwell Hardness | ≤95 HRB |
| Brinell Hardness | ≤217 HB |
Table 3: Typical Physical Properties of 316L Stainless Steel
These physical properties are largely similar to 316, indicating consistent thermal and electrical behavior.
| Property | Value |
| Density | 8.0 g/cm3 |
| Melting Point | 1370−1400 ∘C |
| Thermal Expansion | 16.5 μm/m⋅∘C (20−100∘C) |
| Thermal Conductivity | 16.3 W/m⋅K (100∘C) |
| Modulus of Elasticity | 193 GPa |
| Electrical Resistivity | 7.4×10−7 Ω⋅m (20∘C) |
Table 4: The Standard of Stainless Steel Seamless Tube Size Tolerance Size Chart :
| Standard | OD(D) | Tolerance（MM) | Thickness(S) | Tolerance(MM) | Length | Tolerance | |
| MM | Common | High | MM | MM | |||
| EN 10216-5 HFD | 30≤D≤219.1（D2) | ±1.0% or ±0.5mm, whicever is the greater(取较大者) | T1, T≤4 | ±15% or ±0.6mm, whicever is the greater(取较大者) | L≤6M | +5/0 | |
| T2 | ±12.5% or ±0.4mm, whicever is the greater(取较大者) | ||||||
| 219.1≤D≤610 (D1) | ±1.5% or ±0.75mm, whicever is the greater (取较大者) | T≤0.05D | +22.5%/-15% | 6 | +10/0 | ||
| T1, 0.05D | ±15% or ±0.6mm, whicever is the greater(取较大者) | ||||||
| T2, T>0.09D | ±12.5% or ±0.4mm, whicever is the greater(取较大者) | L>12 | +by agreement/0 | ||||
| EN 10216-5 CFD | D3(D≤219.1) | ±0.75% or ±0.3mm, whicever is the greater(取较大者) | T3 | ±10% or ±0.2mm, whicever is the greater(取较大者) | |||
| D4(D≤219.1) | ±0.5% or ±0.mm, whicever is the greater(取较大者) | T4 | ±7.5% or ±0.15mm, whicever is the greater(取较大者) | ||||
| ASTM A213 HFD | D≤100 | +0.4/-0.8 | D<100,S≤2.4 | +40%/0 | HFD, all size | +5.0/0 | |
| +0.4/-1.2 | D<100,2.4 | +35%/0 | |||||
| +0.4/-1.6 | D<100,3.8 | +33%/0 | |||||
| D<100,S>4.6 | +28%/0 | ||||||
| 100 | +0.4/-1.2 | D>100, 2.4 | +35%/0 | ||||
| 200 | +0.4/-1.6 | D>100,3.8 | +33%/0 | ||||
| D>100,S>4.6 | +28%/0 | ||||||
| ASTM A213 CFD | D<25 | ±0.10 | D≤38.1 | +20%/0 | CFD, D<50.8 | +3.0/0 | |
| 25≤D≤40 | ±0.15 | ||||||
| 40 | ±0.20 | ||||||
| 50≤D<65 | ±0.25 | ||||||
| 65≤D<75 | ±0.30 | D>38.1 | +22%/0 | CFD, D≥50.8 | +5.0/0 | ||
| 75≤D≤100 | ±0.38 | ||||||
| 100 | +0.38/-0.64 | ||||||
| 200 | +0.38/-1.14 | ||||||
| ASTM A269 | D≤13 | ±0.13 | D≤13 | ±15% | D<38 | +3.2/0 | |
| 13 | ±0.13 | 13 | ±10% | ||||
| 38≤D<89 | ±0.25 | D>38 | +4.8/0 | ||||
| 89≤D<140 | ±0.38 | ||||||
| 140≤D<203 | ±0.76 | ||||||
| 203≤D<305 | ±1.01 | ||||||
| 305≤D<356 | ±1.26 | ||||||
| ASTM A270 | D<25 | ±0.13 | For weld pipe all size | ±12.5% | +3.0/0 | ||
| 25-50 | ±0.20 | ||||||
| 50-75 | ±0.25 | ||||||
| 75-100 | ±0.38 | For CD SMLS pipe D≤38.1 | +20%/0 | ||||
| 100-140 | ±0.38 | +5.0/0 | |||||
| 140-200 | ±0.75 | For CD SMLS pipe D>38.1 | +22%/0 | ||||
| 200-300 | ±1.25 | ||||||
Common Applications
The superior corrosion resistance after welding and high precision makes TP316L Stainless Steel Seamless Tube a preferred choice for:
Heat Exchanger and Boiler Tubes: For critical heat transfer applications in corrosive environments.
Pharmaceutical and Food Processing Equipment: In reactors, process lines, and instrumentation where stringent hygiene and frequent welding are required.
Instrumentation Tubing: For precise control lines in chemical and petrochemical plants that handle corrosive fluids.
Marine and Offshore Environments: For welded structures and tubing exposed to saltwater, offering excellent resistance to pitting and crevice corrosion.
Medical Devices: In certain implants and surgical instruments where corrosion resistance, even in welded areas, is paramount.
Aerospace and Automotive: For fluid transfer and structural components requiring high strength and corrosion resistance.
Manufacturing Process
The manufacturing of a Seamless Stainless Steel TP316L Tube follows a precise, multi-step process designed to ensure material integrity and optimal performance, especially for its low-carbon characteristics and tight tolerances:
- Heating: A solid cylindrical billet of 316L stainless steel is heated to a controlled high temperature, making it ductile for subsequent forming.
- Piercing: A rotary piercing mill then drives a mandrel through the center of the heated billet, creating a hollow shell or"tube hollow."
- Cold Working (Rolling and Drawing): The hollow shell undergoes multiple passes using cold drawing or cold rolling techniques. This process meticulously reduces its outer diameter and wall thickness to achieve the precise final dimensions and specified tolerances that are often tighter than those for pipes.
- Finishing: The tube is cut to the required lengths, typically subjected to heat treatment (solution annealing) to relieve stress and optimize mechanical properties, and then cleaned (e.g., pickling and passivation) to enhance its surface finish and critical corrosion resistance. Rigorous inspections, including non-destructive testing, ensure the final product meets stringent quality standards for critical applications.
This meticulous process ensures that every 316L seamless tube delivers exceptional corrosion resistance, particularly in welded applications, and reliable performance in the most challenging and demanding environments.
