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Help CenterASME SA334 Seamless and Welded Alloy Steel Tube For Low Temperature and Cryogenic Service
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ASME SA334 Seamless and Welded Alloy Steel Tube
For Low Temperature and Cryogenic Service – Nickel Alloy Grades 3, 7, 8, 9, 11
Minimum Wall Thickness – Straight-Seam Welded – Heat Treated After Welding
ASME Boiler & Pressure Vessel Code Section II
Product Overview
ASME SA334 / ASTM A334 seamless and welded alloy steel tubes are specifically designed for low temperature and cryogenic service in accordance with the ASME Boiler and Pressure Vessel Code Section II. This specification covers minimum-wall-thickness tubes intended for use at low temperatures and in other applications requiring notch toughness .
The alloy grades contain controlled amounts of nickel to achieve impact toughness at progressively lower temperatures, down to -195°C (-320°F) .
Nickel Alloy Grades Covered:
Grade 3 – 3.5% Nickel steel – Service down to -100°C (-150°F)
Grade 7 – 2.5% Nickel steel – Service down to -75°C (-100°F)
Grade 8 – 9% Nickel steel – Service down to -195°C (-320°F) – LNG standard
Grade 9 – 1.5% Nickel steel – Service down to -75°C (-100°F)
Grade 11 – 36% Nickel steel – Service down to -196°C (-321°F) – extreme cryogenic
Key manufacturing requirements :
Seamless process – Hot finished or cold drawn
Welding process – Straight-seam welded (electric-resistance-welded) with NO filler metal addition during welding operation
Heat treatment after welding – All welded tubes shall be heat treated to control their microstructure
Impact testing – Charpy V-notch testing mandatory for all grades; for welded tubes, specimens shall include the welded joint
Minimum wall thickness – No negative deviation
⚠️ Important Note: Some product sizes may not be available under this specification because heavier wall thicknesses have an adverse effect on low-temperature impact properties .
📌 Welded Tube Note: For welded tubes, impact specimens shall be taken including the welded joint, and flange test and reverse flattening test are required per specification .
✅ ASME SA334 certified – Compliant with ASME Boiler & Pressure Vessel Code Section II; latest edition (ASTM A334/A334M-04a(2021))
✅ Seamless or welded construction – Both options available and fully accepted under same specification
✅ Nickel alloy grades – 1.5% Ni (Grade 9), 2.5% Ni (Grade 7), 3.5% Ni (Grade 3), 9% Ni (Grade 8), 36% Ni (Grade 11)
✅ Minimum wall thickness – No negative deviation – consistent tube integrity at cryogenic temperatures
✅ Charpy impact tested including weld seam – Guaranteed toughness at specified service temperature (weld joint included for welded tubes)
✅ Heat treated after welding – Normalized condition for welded tubes to ensure uniform impact properties
✅ 100% NDT and hydrostatic tested – Weld seam NDT for welded tubes
✅ EN 10204 Type 3.1 MTC + Impact Report provided
✅ Factory direct | Stock available for Grade 3, Grade 8 | Fast delivery
Key Specifications – Alloy Grades
| Parameter | Details |
|---|---|
| Standard | ASME SA334 / ASTM A334 (ASTM A334/A334M-04a(2021)) |
| ASME Code | Boiler & Pressure Vessel Code Section II |
| Product Type | Seamless and Welded Alloy Steel Tube – Low Temperature Service |
| Alloy Grades | 3 (3.5% Ni), 7 (2.5% Ni), 8 (9% Ni), 9 (1.5% Ni), 11 (36% Ni) |
| Wall Type | Minimum wall thickness (no negative deviation) |
| OD Range | 1/8″ – 5″ (3.2mm – 127mm) – typical heat exchanger sizes |
| Wall Thickness | 0.015″ – 0.500″ (0.4mm – 12.7mm) – minimum wall |
| Length | 3m – 12m (fixed or random) – heat exchanger tube lengths |
| Surface Finish | Black / Bare / Oiled / Bright annealed |
| End Finish | Plain / Beveled / Threaded |
| Manufacturing | Seamless (hot finished/cold drawn) or Straight-seam welded (ERW, no filler metal) |
📌 Note: For tubing smaller than 1/2 in. [12.7 mm] in outside diameter, the elongation values given for strip specimens shall apply. Mechanical property requirements do not apply to tubing smaller than 1/8 in. [3.2 mm] in outside diameter and with a wall thickness under 0.015 in. [0.4 mm] .
Welded Tube Manufacturing – ASME SA334 Alloy Grades
| Feature | Requirement | Significance |
|---|---|---|
| Welding process | Straight-seam welded (ERW), no filler metal addition | Prevents weld metal chemistry variation |
| Heat treatment after welding | Required (normalized) | Controls microstructure, ensures weld seam impact toughness |
| Impact testing of weld | Required – specimens include welded joint | Verifies low temperature toughness of weld seam |
| NDT of weld seam | 100% ultrasonic or eddy current | Detects weld seam defects |
| Flange test (welded tubes) | Required per specification | Verifies weld seam ductility |
| Reverse flattening test | Required per specification | Weld seam integrity verification |
💡 Both seamless and welded alloy tubes are fully accepted under ASME SA334 – the key requirements are proper heat treatment after welding and Charpy impact testing including the welded joint for welded tubes.
Nickel Alloy Grades – Temperature Capability
| Grade | Nickel Content | Min Service Temp | Impact Test Temp | Charpy Energy (J) | Product Form Available |
|---|---|---|---|---|---|
| Grade 9 | 1.5% Ni | -75°C (-100°F) | -75°C (-100°F) | ≥20 avg / 16 ind | Seamless or Welded |
| Grade 7 | 2.5% Ni | -75°C (-100°F) | -75°C (-100°F) | ≥18 avg / 14 ind | Seamless or Welded |
| Grade 3 | 3.5% Ni | -100°C (-150°F) | -100°C (-150°F) | ≥18 avg / 14 ind | Seamless or Welded |
| Grade 8 | 9% Ni | -195°C (-320°F) | -195°C (-320°F) | ≥20 avg / 16 ind | Seamless or Welded |
| Grade 11 | 36% Ni | -196°C (-321°F) | -196°C (-321°F) | ≥20 avg / 16 ind | Seamless only |
💡 Grade 8 (9% Nickel) is the industry standard for LNG cryogenic service – provides excellent toughness down to -195°C. Grade 11 (36% Nickel) is used for extreme cryogenic applications down to -269°C in liquid helium service.
📌 Impact Energy Note: For Grades 1 and 6 (carbon grades), the requirement is 18J average; for nickel alloy grades (especially 8, 9, 10, 11), the requirement is 20J average .
Why Nickel Alloys for Low Temperature Service?
| Temperature Range | Material | Nickel Content | Reason |
|---|---|---|---|
| 0°C to -45°C | Carbon steel (Grades 1/6) | 0% | Acceptable Charpy values |
| -45°C to -75°C | 1.5-2.5% Ni (Grades 9/7) | 1.5-2.5% | Nickel improves low temperature toughness |
| -75°C to -100°C | 3.5% Ni (Grade 3) | 3.5% | Higher nickel maintains ductile-to-brittle transition |
| -100°C to -195°C | 9% Ni (Grade 8) | 9% | Austenitic at cryogenic temperatures – excellent toughness |
| Below -195°C | 36% Ni (Grade 11) | 36% | Low thermal expansion + cryogenic toughness |
💡 Nickel is the key alloying element – it lowers the ductile-to-brittle transition temperature, allowing safe operation at cryogenic temperatures.
Chemical Composition – Alloy Grades (ASME SA334)
| Grade | C max | Mn max | P max | S max | Si | Ni | Other |
|---|---|---|---|---|---|---|---|
| Grade 3 | 0.19 | 0.31-0.64 | 0.025 | 0.025 | 0.18-0.37 | 3.18-3.82 | — |
| Grade 7 | 0.19 | ≤0.90 | 0.025 | 0.025 | 0.13-0.32 | 2.03-2.57 | — |
| Grade 8 | 0.13 | ≤0.90 | 0.025 | 0.025 | 0.13-0.32 | 8.40-9.60 | — |
| Grade 9 | 0.20 | 0.40-1.06 | 0.025 | 0.025 | — | 1.60-2.24 | — |
| Grade 11 | 0.10 | ≤0.60 | 0.025 | 0.025 | ≤0.35 | 35.0-37.0 | — |
💡 Nickel content directly determines the minimum service temperature – higher nickel = lower service temperature = higher cost.
Mechanical Properties – Alloy Grades
| Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (max) |
|---|---|---|---|---|
| Grade 3 | ≥450 | ≥240 | ≥30 | — |
| Grade 7 | ≥450 | ≥240 | ≥30 | — |
| Grade 8 | ≥690 | ≥515 | ≥22 | — |
| Grade 9 | ≥435 | ≥315 | ≥28 | — |
| Grade 11 | ≥690 | ≥515 | ≥22 | — |
💡 Grade 8 and Grade 11 have significantly higher strength (≥690 MPa) due to their nickel alloying – suitable for higher pressure cryogenic service .
Low Temperature Charpy Impact Requirements – Alloy Grades
| Grade | Test Temp (°C) | Test Temp (°F) | Min Avg Energy (J) | Min Individual (J) | Test Location |
|---|---|---|---|---|---|
| Grade 3 | -100 | -150 | 18 | 14 | Base metal + weld (for welded) |
| Grade 7 | -75 | -100 | 18 | 14 | Base metal + weld (for welded) |
| Grade 8 | -195 | -320 | 20 | 16 | Base metal + weld (for welded) |
| Grade 9 | -75 | -100 | 20 | 16 | Base metal + weld (for welded) |
| Grade 11 | -196 | -321 | 20 | 16 | Base metal only |
💡 Charpy impact testing is mandatory for all alloy grades – each heat treatment lot must be tested at the temperature specified for the grade. For welded tubes, specimens shall include the welded joint .
Seamless vs Welded – Selection Guide for ASME SA334 Alloy Grades
| Feature | Seamless Tube | Welded (ERW) Tube |
|---|---|---|
| Manufacturing | Hot finished or cold drawn | Electric-resistance-welded, no filler metal |
| Weld seam | No weld seam | Straight-seam welded, normalized after welding |
| Impact testing of weld | Not applicable | Required including weld joint |
| Special tests | Flaring test | Flange test + reverse flattening test |
| NDT requirement | 100% UT/ECT | 100% UT/ECT of weld seam |
| Heat treatment | Normalized | Normalized after welding |
| Cost | Higher | Lower |
| Lead time | Longer | Faster |
| Best application | High pressure, critical service | General low temperature service, cost-sensitive |
| Both accepted under ASME SA334 | Yes – fully compliant | Yes – fully compliant |
💡 Welded alloy tube is fully accepted under ASME SA334 – provided it is straight-seam welded with no filler metal, heat treated after welding, and Charpy impact tested including the welded joint .
Available Sizes – Alloy Grades (Typical Heat Exchanger Sizes)
| OD (inch) | OD (mm) | Typical WT (mm) | Available Grades | Product Form | Application |
|---|---|---|---|---|---|
| 1/4″ – 1/2″ | 6.4 – 12.7 | 0.8 – 1.6 | Grade 3, Grade 8 | Seamless or Welded | Cryogenic instrumentation |
| 1/2″ – 3/4″ | 12.7 – 19.1 | 1.0 – 2.5 | Grade 3, Grade 7, Grade 8 | Seamless or Welded | Small cryogenic HE |
| 3/4″ – 1″ | 19.1 – 25.4 | 1.5 – 3.0 | Grade 3, Grade 8 | Seamless or Welded | Standard cryogenic HE |
| 1-1/4″ – 1-1/2″ | 31.8 – 38.1 | 2.0 – 4.0 | Grade 8 | Seamless or Welded | LNG heat exchangers |
| 2″ – 2-1/2″ | 50.8 – 63.5 | 2.5 – 5.0 | Grade 8, Grade 11 | Seamless | Large cryogenic HE |
| 3″ – 5″ | 76.2 – 127.0 | 3.0 – 12.7 | Grade 8 | Seamless | Special cryogenic |
💡 Most common sizes for cryogenic heat exchangers: 3/4″ (19.1mm), 1″ (25.4mm) OD – available in both seamless and welded product forms. Grade 8 (9% Ni) is the standard material for LNG service .
Heat Treatment Requirements – ASME SA334 Alloy Grades
| Grade | Product Form | Required Heat Treatment | Temperature Range | Purpose |
|---|---|---|---|---|
| Grade 3, 7, 9 | Seamless | Normalized | ≥845°C (1550°F) | Control microstructure |
| Grade 3, 7, 9 | Welded | Normalized after welding | ≥845°C (1550°F) | Ensure weld seam impact properties |
| Grade 8 (9% Ni) | Seamless | Quenched and tempered (Q&T) | 1,750-1,850°F + 1,050-1,150°F | Achieve martensitic structure for -195°C |
| Grade 8 (9% Ni) | Welded | Q&T after welding | As above | Weld seam integrity at cryogenic temps |
| Grade 11 (36% Ni) | Seamless | Annealed | 1,600-1,800°F | Soft condition for extreme cryogenic |
⚠️ Proper heat treatment is essential for achieving low temperature impact properties – Grade 8 must be Q&T (quenched and tempered). Welded tubes must be normalized after welding .
Special Tests for Welded Tubes – ASME SA334 Alloy Grades
| Test | Requirement | Purpose |
|---|---|---|
| Flange Test | Required for welded tubes | Verifies weld seam ductility and integrity |
| Reverse Flattening Test | Required for welded tubes | Weld seam integrity verification |
| Flaring Test | Required for seamless tubes | Tube end expansion capability |
| Impact Test | Required – including welded joint | Weld seam low temperature toughness verification |
| Hardness Test | Required per specification | Grade control for alloy grades |
💡 Welded tubes require additional testing beyond seamless tubes – flange test, reverse flattening test, and impact testing that includes the welded joint are specifically required for welded tubes under SA334 .
Quality Testing & Inspection – ASME SA334 Alloy Grades
| Test | Method | Standard | Coverage | Critical for Alloy Welded |
|---|---|---|---|---|
| Charpy Impact Test | ASTM E23 | ASME SA334 | Per heat treatment lot | Specimens include welded joint |
| Hydrostatic Test | Water pressure | ASME SA334 | 100% | Pressure integrity |
| NDT (UT or ECT) | Non-destructive | ASTM | 100% | Weld seam and base material |
| Tensile Test | ASTM E8 | ASME SA334 | Per heat | Strength verification (≥690 MPa for Grade 8) |
| Hardness Test | Rockwell/Brinell | ASME SA334 | Per lot | Grade control |
| Flattening Test | Ductility | ASME SA334 | Per lot | Tube formability |
| Flaring Test | Expansion | ASME SA334 | Per lot | Tube end expansion (seamless) |
| Flange Test | Weld seam | ASME SA334 | Per lot | Welded tube specific |
| Reverse Flattening Test | Weld seam | ASME SA334 | Per lot | Welded tube specific |
| Dimensional Inspection | Micrometer | ASTM A450 | 100% | Size verification |
💡 ASME SA334 requires comprehensive testing for alloy welded tubes – flange test, reverse flattening test, and Charpy impact including weld seam are specific requirements .
Heat Treatment Temperature Reference
| Grade | Normalizing Temp | Q&T Austenitizing | Q&T Tempering |
|---|---|---|---|
| Grade 3, 7, 9 | 1,550-1,700°F (845-925°C) | N/A | N/A |
| Grade 8 | 1,750-1,850°F for Q&T | 1,750-1,850°F | 1,050-1,150°F |
| Grade 11 | 1,600-1,800°F | N/A | N/A |
💡 Grade 8 requires quenching and tempering, not simple normalization – this is critical to achieve the required microstructure for service at -195°C .
Grade Selection Guide – Alloy Grades by Temperature
| Service Temperature | Minimum Grade Required | Nickel Content | Product Form Available | Cost Level |
|---|---|---|---|---|
| -45°C to -75°C | Grade 9 (1.5% Ni) or Grade 7 (2.5% Ni) | 1.5-2.5% | Seamless or Welded | $$ |
| -75°C to -100°C | Grade 3 (3.5% Ni) | 3.5% | Seamless or Welded | $$$ |
| -100°C to -195°C | Grade 8 (9% Ni) | 9% | Seamless or Welded | $$$$ |
| Below -195°C | Grade 11 (36% Ni) | 36% | Seamless only | $$$$$ |
⚠️ Do NOT use carbon steel (Grades 1 or 6) below -45°C – carbon steel does not have sufficient Charpy impact toughness below this temperature. Nickel alloy grades are required.
Applications – Nickel Alloy Low Temperature Tubes
| Industry | Application | Recommended Grade | Service Temp | Tube Size | Product Form |
|---|---|---|---|---|---|
| LNG Terminals | Cryogenic heat exchangers | Grade 8 (9% Ni) | -160°C | 3/4″ – 2″ OD | Seamless or Welded |
| LNG Carriers | Cargo heat exchangers | Grade 8 (9% Ni) | -160°C | 1″ – 1-1/2″ OD | Seamless or Welded |
| Air Separation Units | Cryogenic heat exchangers (O2/N2/Ar) | Grade 8 (9% Ni) | -195°C | 1/2″ – 2″ OD | Seamless |
| Petrochemical | Low temperature heat exchangers | Grade 3 (3.5% Ni) | -100°C | 3/4″ – 1-1/2″ OD | Seamless or Welded |
| Cryogenic Storage | Transfer line tubing | Grade 8, Grade 11 | -195°C to -196°C | 1″ – 4″ OD | Seamless |
| Refrigeration | Low temperature systems | Grade 3, Grade 7 | -75°C to -100°C | 1″ – 2″ OD | Seamless or Welded |
| Liquid Helium Systems | Extreme cryogenic | Grade 11 (36% Ni) | -269°C | 1/2″ – 2″ OD | Seamless |
| Cold Boxes | Cryogenic process equipment | Grade 8 (9% Ni) | -195°C | 1/2″ – 1-1/2″ OD | Seamless |
💡 Grade 8 (9% Nickel) is the most common alloy grade for LNG and cryogenic heat exchanger applications . Welded Grade 8 tubes are available for non-critical pressure applications – providing cost savings while maintaining cryogenic toughness.
Tube Tolerances – ASME SA334 (Per ASTM A450)
OD Tolerances (Cold Drawn):
| OD (mm) | Tolerance (mm) | OD (inch) | Tolerance (inch) |
|---|---|---|---|
| ±0.10 | ±0.004″ | ||
| 25.4 – 38.1 | ±0.15 | 1″ – 1.5″ | ±0.006″ |
| 38.1 – 50.8 | ±0.20 | 1.5″ – 2″ | ±0.008″ |
| 50.8 – 63.5 | +0.38/-0.64 | 2″ – 2.5″ | +0.015″/-0.025″ |
Wall Thickness Tolerances (Minimum Wall – No Negative Deviation):
| Manufacturing | Condition | Tolerance |
|---|---|---|
| Cold Drawn | OD ≤38.1mm | +20% / -0 |
| Cold Drawn | OD >38.1mm | +22% / -0 |
| Hot Rolled | OD ≤101.6mm, WT ≤2.4mm | +40% / -0 |
💡 Minimum wall thickness means the actual wall thickness will never be less than the specified value – critical for pressure integrity at cryogenic temperatures .
Welding Recommendations for Field Installation – Alloy Grades
| Grade | Preheat Required | PWHT Required | Low Hydrogen Required | Filler Metal Recommendation |
|---|---|---|---|---|
| Grade 3 (3.5% Ni) | 120°C min | Yes | Required | ER80S-Ni1 |
| Grade 7 (2.5% Ni) | 95°C min | Yes | Required | ER80S-Ni1 |
| Grade 8 (9% Ni) | 120°C min | Yes | Required | ENiCrFe-9 (nickel-chromium-iron) |
| Grade 9 (1.5% Ni) | 95°C min | Yes | Required | ER80S-Ni1 |
| Grade 11 (36% Ni) | Optional | No | Required | ERNiFeCr-1 |
⚠️ Nickel alloy grades require preheat, PWHT, and low hydrogen practices – failure to follow proper procedures can cause cracking in cryogenic service. For Grade 8, use ENiCrFe-9 filler metal specifically designed for 9% nickel steel.
Mill Test Certificate – Alloy Grades
ASME SA334 Certificate of Compliance – Standard
EN 10204 Type 3.1 MTC – Provided with heat number
EN 10204 Type 3.2 – Available upon request (third-party: SGS, BV, TUV, DNV)
Low Temperature Impact Test Report – Included (Charpy values at specified temperature; for welded tubes, includes weld joint specimens)
Weld Seam Test Reports – Flange test and reverse flattening test results for welded tubes
Heat Treatment Records – Q&T records for Grade 8
Flattening/Flaring Test Reports – Per ASTM A450 requirements
Traceability: Full traceability from melt to finished tube
Packaging & Shipping – Alloy Tubes
| Item | Details |
|---|---|
| Packaging | Hexagonal bundles with steel strapping |
| Protection | Plastic end caps + protective paper (Grade 8 requires clean, oil-free surface) |
| Marking | Stencil/spray with Grade, size, heat number, ASME SA334, impact test date, product form (S/W) |
| Documentation | MTC + Impact Report included |
| Lead time | 20–30 days (Grade 3, 7), 30–45 days (Grade 8 seamless), 35–50 days (Grade 8 welded), 45–60 days (Grade 11) |
| Port | Tianjin / Shanghai / Guangzhou |
Why Choose Our ASME SA334 Alloy Tubes?
| Advantage | Description |
|---|---|
| Both seamless and welded alloy tubes | Full range of manufacturing options under one specification |
| Welded alloy tube specialist | ERW alloy tubes with full heat treatment and Charpy impact testing including weld joint |
| Grade 8 (9% Ni) expert | Industry standard for LNG cryogenic heat exchangers – Q&T heat treatment |
| In-house impact testing | Cooling tanks from 0°C to -196°C – Charpy impact testing including weld seam for welded tubes |
| Minimum wall thickness | No negative deviation – consistent tube integrity for cryogenic service |
| Full weld seam testing | Flange test + reverse flattening test per specification requirements |
| Full traceability | EN 10204 3.1 MTC + Impact Report with heat number |
| Comprehensive testing | Charpy impact (including weld seam) + tensile + hardness + flattening + flaring + flange + reverse flattening + ECT + hydrostatic |
| Welding support | Preheat, PWHT, and filler metal recommendations for nickel alloy grades |
| Global export | Shipped to LNG and cryogenic projects worldwide |
| Flexible MOQ | Small orders accepted for Grade 3 and Grade 8 stock sizes |
Contact for Quote – ASME SA334 Alloy Tubes
Please provide the following details for your low temperature alloy tube project:
Grade : 3 / 7 / 8 / 9 / 11
Manufacturing : Seamless / Welded (ERW)
OD (inch / mm) : _______ (3/4″, 1″ most common for Grade 8)
Wall Thickness (mm / BWG) : _______
Length (m) : _______
Quantity : _______ (pieces / meters / tons)
Application : LNG heat exchanger / Cryogenic HE / Air separation / Other _______
Service Temperature : _______ °C
Inspection : Standard / Third-party (SGS/BV/TUV/DNV)
📧 Email: yjhtrade@gmail.com
📞 WhatsApp: +86 15106174543
🌐 Website: www.wuxihengzhihui.com
Reply within 24 hours.
FAQ – ASME SA334 Seamless and Welded Alloy Grades
Q1: What are the alloy grades in ASME SA334?
A: Alloy grades include Grade 3 (3.5% Ni), Grade 7 (2.5% Ni), Grade 8 (9% Ni), Grade 9 (1.5% Ni), and Grade 11 (36% Ni) – all contain nickel for low temperature toughness .
Q2: Is ASME SA334 available as welded alloy tube?
A: YES – ASME SA334 covers both seamless and straight-seam welded (ERW) carbon and alloy steel tubes for low temperature service .
Q3: Does welded alloy tube require heat treatment for low temperature service?
A: YES – All welded tube shall be heat treated after welding (normalized) to control microstructure and ensure weld seam impact toughness .
Q4: Does the weld seam require impact testing?
A: YES – For welded pipe, impact specimens shall be taken including the welded joint . This is a critical requirement that distinguishes SA334 welded tube from standard welded tube.
Q5: What are the additional tests for welded tubes?
A: Welded tubes require flange test and reverse flattening test in addition to standard tests . These specifically verify weld seam integrity.
Q6: What is the most popular alloy grade for LNG service?
A: Grade 8 (9% Nickel steel) – industry standard for LNG heat exchangers and cryogenic service down to -195°C (-320°F) .
Q7: What is the difference between seamless and welded ASME SA334 alloy tube?
A: Seamless – no weld seam, higher cost, flaring test required. Welded – ERW with heat treatment, lower cost, flange test + reverse flattening test + impact testing including weld joint required .
Q8: Does Grade 8 require special heat treatment?
A: Yes – Grade 8 requires quenching and tempering (Q&T) to achieve the proper microstructure for cryogenic service at -195°C .
Q9: What welding filler metal is required for Grade 8?
A: ENiCrFe-9 – a nickel-chromium-iron electrode specifically designed for welding 9% nickel steel to maintain cryogenic toughness.
Q10: Do you provide impact test reports including weld seam?
A: Yes – for welded tubes, our impact test reports include specimens taken from the base metal and the welded joint per ASME SA334 requirements .
Q11: Do you provide third-party inspection?
A: Yes. SGS, BV, TUV, DNV, or any customer-specified agency.
Q12: Do you offer free samples?
A: 30cm sample of Grade 3 or Grade 8 available on request (seamless or welded). Grade 11 samples require lead time. Shipping fee applies.
Related Products – Low Temperature Systems
ASME SA334 – Low temperature tubes – seamless and welded, carbon and alloy (this product)
ASME SA333 – Low temperature pipe (larger diameters)
ASME SA350 – Low temperature flanges (LF1, LF2, LF3, LF5)
ASME SA420 – Low temperature fittings (WPL3, WPL6, WPL9)
ASME SA320 – Low temperature fasteners (L7, L7M, B8)
ASTM A450 – General requirements for carbon and alloy steel tubes
Tags: ASME SA334 Alloy Steel Tube Low Temperature Tube Seamless Tube Welded Tube ERW Tube Grade 8 Tube 9% Nickel Tube LNG Heat Exchanger Cryogenic Tube Nickel Alloy Tube
Quick Reference – Nickel Alloy Grade Selection
| Service Temp | Grade | Nickel % | Product Form | Tensile (MPa) | Application |
|---|---|---|---|---|---|
| -45°C to -75°C | Grade 9 | 1.5% | Seamless or Welded | ≥435 | Low temp HE |
| -45°C to -75°C | Grade 7 | 2.5% | Seamless or Welded | ≥450 | Deeper low temp |
| -75°C to -100°C | Grade 3 | 3.5% | Seamless or Welded | ≥450 | Medium cryogenic |
| -100°C to -195°C | Grade 8 | 9% | Seamless or Welded | ≥690 | LNG cryogenic – most common |
| Below -195°C | Grade 11 | 36% | Seamless only | ≥690 | Extreme cryogenic |
Comparison – Seamless vs Welded ASME SA334 Grade 8 (9% Nickel)
| Feature | Seamless | Welded (ERW) |
|---|---|---|
| Standard coverage | Yes | Yes |
| Heat treatment | Q&T | Q&T after welding |
| Impact test | Required | Required – including weld joint |
| NDT requirement | 100% UT/ECT | 100% UT/ECT of weld seam |
| Flaring test | Required | Not applicable |
| Flange test | Not applicable | Required |
| Reverse flattening | Not applicable | Required |
| Cost | Higher | Lower |
| Lead time | Longer | Faster |
| Best for | High pressure, critical cryogenic | General LNG heat exchangers |
Alloy Grade Chemical Comparison
| Grade | Ni % | C max | Key Feature | Seamless | Welded |
|---|---|---|---|---|---|
| Grade 9 | 1.5-2.2 | 0.20 | Low nickel, economic | ✓ | ✓ |
| Grade 7 | 2.0-2.6 | 0.19 | Medium nickel | ✓ | ✓ |
| Grade 3 | 3.2-3.8 | 0.19 | 3.5% nickel – common | ✓ | ✓ |
| Grade 8 | 8.4-9.6 | 0.13 | 9% nickel – LNG standard | ✓ | ✓ |
| Grade 11 | 35.0-37.0 | 0.10 | 36% nickel – Invar type | ✓ | — |
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ASME SA334 Carbon Steel Tube Supplier– Carbon Grade Technical DataNegotiableMOQ: 1 Metric Ton
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ASME SA334 Seamless Alloy Steel Tube For Low Temperature and Cryogenic Service – Nickel Alloy Grades 3, 7, 8, 9, 11NegotiableMOQ: 1 Metric Ton
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ASME SA334 Seamless Alloy Steel Tube – Low Temperature Service Nickel Alloy Grades 3, 7, 8, 9, 11NegotiableMOQ: 1 Metric Ton
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ASME SA334 Seamless Alloy Steel Tube – Cryogenic ServiceNegotiableMOQ: 1 Metric Ton
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ASME SA334 – Nickel Alloy Pipe Supplier Grade Technical DataNegotiableMOQ: 1 Metric Ton
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ASME SA334 Seamless Carbon and Alloy Steel Tube For Low Temperature Service – Grades 1, 3, 6, 7, 8, 9, 11NegotiableMOQ: 1 Ton
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ASME SA334 Seamless Tube – Low Temperature Service Grades 1, 3, 6, 7, 8, 9, 11NegotiableMOQ: 1 Metric Ton
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ASME SA334 Seamless Low Temperature Tube – Cryogenic ServiceNegotiableMOQ: 1 Metric Ton
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ASME SA334 Seamless Low Temperature Pipe Supplier- Grades 1~11NegotiableMOQ: 1 Metric Ton
