With the development of the chemical industry, the materials of chemical equipment are also constantly updated. From the initial glass lining and resin lining to the current Hastelloy alloy, it is more and more widely used. When selecting materials for chemical equipment, we must not only consider their corrosion resistance, but also comprehensively consider their strength, processability, and economy. Hastelloy has been used since the 1930s. Its design and processing technology are basically the same as stainless steel, and it has mature experience.
1. Classification and characteristics of Hastelloy
Hastelloy is mainly divided into three major categories: Ni-Mo, Ni-Cr-Mo and Ni-Cr-Fe-Mo-Cu. The representative of Ni-Mo type is Hastelloy B, which has good corrosion resistance in non-oxidizing acid medium. The representative of the Ni-Cr-Mo class is Hastelloy C, which has excellent corrosion resistance in both oxidizing and non-oxidizing acids. The representative of Ni-Cr-Fe-Mo-Cu is Hastelloy G, which has good corrosion resistance in hot phosphoric acid and hot sulfuric acid.
2. Application of Hastelloy in equipment design
The strength of Hastelloy is 1.5 times higher than that of stainless steel with the same ductility, and its good corrosion resistance can reduce the corrosion allowance and achieve thinner walls and lighter weight. ASME specifies the maximum allowable stress for Hastelloy alloys. Hastelloy can be used to make various pipe fittings, such as elbows, tees, flanges, etc. Considering cost, it is recommended to use sliding sleeve flange.
3. Processing of Hastelloy alloy
Hastelloy can be used for conventional pipe bending, deep drawing and other processing, but due to the strong work hardening effect, the frequency is 2-3 times higher than that of stainless steel. For example, when cold pressing method is used for deep drawing, the R zone needs to undergo a solid solution treatment. Punching hole diameter ≥ 2 times of plate thickness, space distance ≥ 2-3 times of hole diameter. Stress relief annealing is usually performed after processing.
4. Welding of Hastelloy alloy
The weldability of Hastelloy is similar to that of austenitic stainless steel. Once the characteristics are mastered, no special technology is required for welding. Gas shielded welding such as TIG and MIG welding, manual arc welding or electron beam welding can be used. Gas welding is not available and submerged arc welding is not recommended for large heat affected zones. The welding wire is the same as the base metal. Remove grease and dirt before welding, machine the bevel, polish after plasma cutting, and remove more than 3mm. The groove opening is relatively open and the molten metal flows poorly. Except for types B and C, it can be used without heat treatment after welding. The inspection adopts penetrant or radiographic flaw detection, and does not require magnetic particle or ultrasonic flaw detection.
5. Mechanical processing of Hastelloy alloy
Hastelloy is a difficult-to-machine material, and the processing time and tool wear are higher than those of stainless steel, but choosing the right conditions can reduce the difference.
Although the price of Hastelloy is high, the design and processing are similar to stainless steel. Reasonable design can increase the service life, and the cost does not need to exceed stainless steel. Hastelloy has been widely used in various chemical equipment and can replace expensive high alloys in many aspects. Hastelloy has the potential to replace stainless steel in a wider range, and its prospects are very bright.
In short, Hastelloy has good physical and chemical properties and has become an irreplaceable material in chemical production. However, due to the high price, it is still necessary to comprehensively consider the use conditions and requirements of the equipment when choosing to use it, and choose a more cost-effective variety. It is believed that with the improvement of production technology and the expansion of the market, the price of Hastelloy will gradually decrease and its application scope will become wider.
Tianjin Anton Metal Manufacture Co., Ltd. is a company specializing in the production of various nickel-based alloys, Hastelloy alloys and high-temperature alloy materials. The company was established in 1989 with a registered capital of 10.0 million, specializing in the production and sales of alloy materials. Anton Metal’s products are widely used in aerospace, chemical industry, electric power, automobile, nuclear energy and other fields, and can also provide customized alloy material solutions according to customer needs. If you need to know the price consultation of alloy materials or provide customized alloy material solutions, please feel free to contact the sales staff.
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Post time: Nov-25-2023
