Overview
ASTM B444 is a very commonly used standard for nickel alloy seamless pipes. The standard mainly includes Inconel 625 (UNS N06625) and two other materials. The main products are seamless pipes and tubes. In this article, we will introduce the important requirements mentioned in ASTM B444 in detail. This will allow you to better control the quality when ordering.
Inconel 625 UNS N06852 UNS N06219
The ASTM B444 standard includes three grades.
Nickel-chromium-molybdenum-niobium alloy: Inconel 625 (UNS N06625), UNS N06852.
Nickel-chromium-molybdenum-silicon alloy: UNS N06219.
Among them, Inconel 625 is the most commonly used. Compared with nickel-chromium alloy, molybdenum element is added to Inconel 625 alloy, which further improves the comprehensive corrosion resistance of the alloy. Inconel 625 also contains a certain amount of niobium. High strength is reinforced by solid solution.
Chemical composition
Inconel 625 (UNS N06625)
ASTM B444 mainly specifies the technical requirements for seamless pipes and tubes. Among them, materials with an outer diameter of 127mm or less are defined as seamless pipes. Materials with an outer diameter of 127mm or more are seamless pipes.
Mechanical properties
| Material & Condition | Tensile Strength Min. ksi (MPa) | Yield Strength (0.2% Offset) Min. ksi (MPa) | Elongation in 2 in. or 50mm (or 4D), Min. % | |
|---|---|---|---|---|
| Inconel 625 (UNS N06625) | ||||
| Grade 1 (Annealed) | 120 (827) | 60 (414) | 30 | |
| Grade 2 (Solution Annealed) | 100 (690) | 40 (276) | 30 | |
| UNS N06219 | ||||
| All (Solution Annealed) | 96 (660) | 39 (270) | 30 | |
| UNS N06852 | ||||
| All (Solution Annealed) | 85 (586) | 35 (241) |
Delivery State
In ASTM B444, UNS N06852 and UNS N06219 are specified only in the solution treated state.
For Inconel 625 (UNS N06625), the standard specifies the following two states:
Grade 1 (Annealed): Grade 1 is the annealed state with higher strength and suitable for use at temperatures up to 1100°F (593°C). In most cases, Inconel 625 will be used at this temperature. Therefore, Grade 1 is the default delivery state for Inconel 625 seamless pipes.
Grade 2 (Solution Annealed): Grade 2 requires the material to be delivered in the solution annealed state. When the material is used above 1100°F (593°C). The Grade 2 state helps improve the creep properties and fatigue properties of the alloy. Therefore, if you need to use Inconel 625 seamless pipes and tubes at higher temperatures, you should choose Grade 2.
Conclusion
ASTM B444 is mainly used for seamless pipes and tubes of nickel-chromium-molybdenum-niobium alloy and nickel-chromium-molybdenum-silicon alloy. Among them, Inconel 625 seamless pipe is the most commonly used material in the standard. Gnee Steel manufactures this material strictly in accordance with ASTM B444 standard.
Gnee Steel produces Inconel 625 seamless pipes and tubes in accordance with ASTM B444 standard.
