Material grade: HastelloyB-3 Hastelloy Alloy
United States grade: UNSN10675
Hastelloy B-3 (n10675) Hastelloy
Hastelloy B-3 (n10675) is a nickel-based high-temperature alloy composed of nickel, molybdenum, cobalt and other elements, with a nickel content of about 65%. Hastelloy B-3 (n10675) nickel-based alloy is a new material developed based on Hastelloy B2. It improves the thermal stability and corrosion resistance of the material and improves the thermal forming and cold forming properties. In recent years, it has been used more and more in the production and manufacturing of chemical equipment.
Chemical composition of Hastelloy B-3 (n10675)
| C≤ | Si≤ | Mn≤ | P≤ | S≤ | Cr≥ | Ni≥ | Mo≥ | Cu≤ |
| 0.01 | 0.10 | 3.00 | 0.030 | 0.010 | 1.00-3.00 | 65.0 | 27.0-32.0 | 0.20 |
| Nb/Ta≤ | Al≤ | Ti≤ | Fe≤ | Co≤ | V≤ | W≤ | Ni+Mo | Ta≤ |
| 0.20 | 0.50 | 0.20 | 1.00-3.00 | 3.00 | 0.20 | 3.00 | 94.0-98.0 | 0.20 |
Main features, welding and processing of Hastelloy B-3 (n10675)
●Material analysis: Solid-soluble mechanical properties of Hastelloy B-3 (n10675) alloy plate: As the heating temperature increases, its tensile strength, yield strength and elastic modulus decrease, while the elongation, thermal expansion coefficient, thermal conductivity and specific heat increase slightly; with the increase of cold deformation rate, its hardness, tensile strength and yield strength increase, and the elongation decreases.
●Framing process characteristics: Through analysis, the forming process characteristics of Hastelloy B3 alloy mainly include:
(1) The results show that the cold forming conditions of Hastelloy and B alloy are relatively high.
(2) Hastelloy B-3 has higher hardness than austenitic stainless steel and has a more obvious tendency to work harden, so it requires greater pressure or step-by-step forming during cold forming.
(3) When the cold forming deformation rate of Hastelloy B-3 is less than 10%, the corrosion resistance of the processed parts is not affected, but the existence of residual stress will cause thermal cracks to occur in the weld. Therefore, for later welding workpieces, the influence of residual stress should be eliminated as much as possible.
(4) Frequently deformed cold forming can improve the yield ratio of Hastelloy B-3 material, and improve the stress corrosion sensitivity and crack sensitivity of the material.
(5) Hastelloy B-3 is very sensitive to low-melting point metals such as oxidation medium, sulfur, phosphorus, and lead at high temperatures.
(6) Hastelloy B3 will produce a brittle phase within the temperature range of 600 to 800°C and over a long heating time, resulting in a decrease in elongation. In addition, when external forces or deformation are limited, thermal cracks are prone to occur within this temperature range. Therefore, the temperature must be controlled above 900°C.
(7) Before processing and pressing the Hastelloy B-3 material, the mold surface in contact with the workpiece should be cleaned. Lubrication method can be used during cold processing, and degreasing or alkali washing should be carried out immediately after molding.
(8) After the workpiece is cooled out of the oven, the surface oxide film is thick and should be fully pickled. If there is residual oxide film, cracks may occur during the next stamping. If necessary, sandblasting can be performed before pickling.
Welding and forming
(1) Before forming, if the blank needs to splice the weld, choose the GTAW welding method, so as to better protect the weld from oxidation. If manual arc welding is used, it is easy to cause oxidation of the intermediate bead. Even if each layer has been polished and cleaned, it is difficult to ensure a thorough cleaning, and there are a small amount of residual oxide layers, which may also form factors that affect the processing performance of the weld. The attachments and oxide layers on the bevel and the surface of the base material must be removed before welding, because the presence of oxide film and impurities will affect the performance of the weld and heat-affected zones. *** Use small current to avoid too slow speed and swing. The temperature between layers is controlled below 100℃. Argon should be used on the front and back to avoid high temperature oxidation and combustion of alloy elements. Before pressing, the weld surface should be polished smoothly, the thicker oxide layer on the weld surface should be removed, and pickled. Because the oxide layer of the weld of Hastelloy B-3 material is hard, it is difficult to remove by direct pickling. Small cracks are easily generated during stamping and forming, which affects the performance of the weld.
(2) The advantage of thermoforming is that it can be formed at one time to avoid work hardening. If the forming temperature can be controlled well, heat treatment can be avoided. However, during the thermoforming process, the temperature varies greatly and the various regions are different. Even the surfaces directly in contact with the mold may be much lower than the temperature inside the metal, making it difficult to measure and control. Once the local materials enter the sensitive temperature zone during processing, it is difficult to eliminate defects such as microcracks in the subsequent solid solution heat treatment. According to the experience of the processing plant, the cold forming process was selected. Pressing method*** molding method. When spinning is necessary, cold spinning or warm spinning should be used, and the temperature should not exceed 400℃.