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ASTM B444-18
Standard Specification for Nickel-Chromium-Molybdenum-Columbium Alloys (UNS N06625 and UNS N06852) and Nickel-Chromium-Molybdenum-Silicon Alloy (UNS N06219) Pipe and Tube
This specification covers UNS N06625 and UNS N06852 nickel-chromium-molybdenum-columbium alloys and UNS N06219 nickel-chromium-molybdenum-silicon alloy in the form of cold-worked seamless pipe and tube. ASME SB 407 UNS N06625 products are furnished in annealed Grade 1 and solution annealed Grade 2.
UNS N06625 Products are Furnished in Two Grades:
The ASTM B444 / ASME SB 444 standard governs the technical and physical manufacturing baselines for cold-worked seamless pipes and tubes fabricated from Nickel-Chromium-Molybdenum-Columbium alloy (UNS N06625 / Inconel 625) and Nickel-Chromium-Molybdenum-Silicon alloy (UNS N06219).
The specification separates Inconel 625 into two distinct, heat-treated grades based on your targeted operating temperatures and structural requirements:
- Grade 1 (Annealed): The material is thermally treated at a minimum of 1600°F (871°C). This grade is typically specified for general corrosion environments and applications requiring high room-temperature tensile properties.
- Grade 2 (Solution Annealed): The material is solution heat-treated at a minimum of 2000°F (1093°C), with or without subsequent stabilization. Grade 2 is mandatory for high-temperature service environments (typically above 1100°F / 593°C) where resistance to creep and stress-rupture is critical.
Nickel Alloy N06625 High Quality
ASTM B444 Inconel 625 material shall undergo tensile testing and shall conform to the required room temperature tensile properties like tensile strength, yield strength, and elongation depending on the heat treatment used including small diameter and light-walled tubing. Each pipe or tube shall undergo hydrostatic testing and conform to the allowable fiber stress and also be examined with a nondestructive electric test as prescribed.
Permissible Variations for Small-Diameter and Light-Wall Tube (Converter Sizes)
| Specified Outside Diameter in. (mm) |
Outside Diameter | Inside Diameter | Wall Thickness, % | |||
| Plus in (mm) | Minus in (mm) | Plus in (mm) | Minus in (mm) | Plus | Minus | |
| Under 3⁄32 (2.4) | 0.002 (0.05) | 0 | 0 | 0.002 (0.05) | 10 | 10 |
| 3⁄32 to 3⁄16 (2.4 to 4.8), excl | 0.003 (0.08) | 0 | 0 | 0.003 (0.08) | 10 | 10 |
| 3⁄16 to 1⁄2 (4.8 to 12.7), excl | 0.004 (0.1) | 0 | 0 | 0.004 (0.1) | 10 | 10 |
| 1⁄2 to 11⁄4 (12.7 to 31.8), incl | 0.005 (0.13) | 0 | 0 | 0.005 (0.13) | 10 | 10 |
Tolerances on Cut Lengths of Light-Wall Tube
| Length, ft (m) | Tube Size, in. (mm) | Permissible Variations, in. (mm) | |
| Over | Under | ||
| Under 1 (0.30) | up to 1.250 (31.8), incl | 1/32 (0.8) | 0 (0) |
| 1 to 4 (0.30 to 1.22), incl | up to 1.250 (31.8), incl | 1/16 (1.6) | 0 (0) |
| Over 4 to 10 (1.22 to 3.0), incl | up to 1.250 (31.8), incl | 3/32 (2.4) | 0 (0) |
| Over 10 (3.0) | up to 1.250 (31.8), incl | 3/16 (4.8) | 0 (0) |
Dimensional Sizing Availability
Outside Diameter (OD) Range: 1/8" NPS up to 12" NPS (10.3mm up to 323.8mm Nominal Bore).
Wall Thickness (WT) Dimensions: Comprehensive wall schedules including SCH 10S, SCH 40S, SCH 80S, SCH 160, SCH XS, and SCH XXS, as well as precise customized metrics.
Surface Finishes: Solution Annealed & Pickled (industrial dull white finish) or Bright Annealed (BA smooth mirror surface).
Length Capacities: Single Random Lengths (SRL), Double Random Lengths (DRL), or cut-to-length options down to millimeter tolerances to minimize material waste.
Rigorous Quality Control & Non-Destructive Testing
Every individual pipe length manufactured by HT PIPE passes through an advanced non-destructive testing matrix prior to seaworthy packing and container loading:
Hydrostatic Pressure Testing: Verifies structural integrity under intense pressure containment configurations.
Ultrasonic (UT) & Eddy Current Testing: 100% scanning across the seamless profile to identify internal micro-fissures or subsurface wall irregularities.
Positive Material Identification (PMI): Rapid X-ray fluorescence verification to guarantee chemical composition matches the alloy grade.
One-Stop Package Integration for Large-Scale Projects
Eliminate the logistical friction of managing fragmented multi-vendor supply chains. HT PIPE delivers complete, single-source industrial packages with unified traceability numbers. Along with ASTM B444 UNS N06625 pipes and tubes, we engineer and supply matching:
- ASTM B443 Inconel 625 Plates, Sheets & Slit Strips
- ASTM B446 UNS N06625 Forged Bars, Rods & Hexagonal Profiles
- Forged Fittings & ASME B16.5 / B16.47 Flanges (Elbows, Equal/Reducing Tees, Concentric Reducers, Weldnecks, Blind Flanges)
- Custom Pre-Fabricated Pipe Spools: Fully assembled, welded, and non-destructively tested to match your isometric engineering prints.
