Mechanical properties of Hastelloy alloys
1. Hastelloy alloy comes from Hastelloy, starting from Hastelloy B alloy, and is applied to the rocket nozzle of aircraft; Subsequently, Hastelloy C alloy has been applied and promoted in chemical industry, petrochemical industry, nuclear energy industry and pharmaceutical industry. The following Hastelloy X alloy showed better high temperature resistance, along with the rapid growth of the jet industry.
2. As early Hasloy B, Hasloy C and Hasloy X alloys need to be solidly treated after welding, otherwise, the corrosion resistance of the welding heat affected zone will be greatly reduced; So these alloys have been gradually improved or no longer used;
3. The key reason affecting the welding performance of the above materials lies in the content of C and Si. Due to the emergence and improvement of refining technology, the welding problems of Hastelloy alloy have been improved. It is very regrettable that many production and promotion units of Hastelloy alloy replace the earlier Hastelloy alloy with the later improved Hastelloy alloy, which not only does not reduce the content of C and Si, but returns to the previous high Si and high C content. The promotion of special steel business has a long way to go.
4. The reductive medium resistant Hasloy B series alloy is improved on the basis of Hasloy B grade. The key points of improvement include extremely low content of C and Si to improve the performance of welding area, further alloying idea, application of pure purification of molten steel idea, etc. In this way, Hasloy B-2, Hasloy B-3 and Hasloy B-4 alloys appear in the B series of Hasloy alloy. Among them, Hastelloy B-2 alloy can solve the performance problem of welding area to a certain extent. Hastelloy B-3 solves the disadvantage that Hastelloy B-2 is easy to precipitate Ni-Mo precipitation and harden, and greatly improves the performance of hot and cold working.
5. In the process of improvement of reductive environmental application materials Hastelloy B series; The Hasloy C series alloys in the REDOX compound environment are also continuously improved. The Hasloy C276 alloy has improved the performance of the welding area to some extent due to the low content of C and Si, but it is still not satisfactory, and the machining performance has not been improved. The Hasloy C22 material completely solves the corrosion resistance problem of the welding area, the processing performance problem, is mainly solved on the basis of the material cost does not improve, so Hasloy C22 material is the Hasloy C series of cost-effective materials, will be used in large quantities in the future; The newly developed Hastelloy C2000 material adds Cu into the alloy, which expands the corrosion ability of Hastelloy C alloy in the reducing environment, which provides the possibility for safe use, high equipment life requirements and new process trial production occasions.
Hastelloy is an ultra-low carbon, Ni, Mo, Cr series nickel base, corrosion resistance, high temperature resistant material Hastelloy, because it has good high temperature resistance, oxidation resistance, weld affected zone corrosion resistance, has good long-term thermal stability and processability, is used in agricultural chemical, nuclear facilities, biopharmaceutical and other harsh industrial environment. It in wet oxygen, sulfite, acetic acid, formic acid and strong oxidizing salt in the medium, also has good corrosion resistance, uniform corrosion resistance and resistance to intergranular corrosion, so in the chemical industry is also used, combined with haselloy gold conductivity and thermal conductivity is much lower than low carbon steel, and the resistivity and expansion rate are much higher than low carbon steel, molten pool fluidity is poor, poor wetness, penetration is small, the depth of penetration.