Superalloy is a cutting-edge material with high corrosion resistance, high temperature resistance and high temperature strength. It is widely used in aviation, aerospace, energy, chemical industry and other fields. In the manufacturing process of high-temperature alloys, the forging process is a key link and an important link in ensuring the performance of high-temperature alloy materials. This article will introduce the classification of high-temperature alloys, forging process principles, post-forging cooling methods, etc.
1. Types of high temperature alloys
High-temperature alloys can be divided into iron-based alloys and nickel-based alloys based on the metal components they contain. Iron-based superalloys can be divided into pearlite, martensite and austenite according to their normalized structures; the matrix structure of nickel-based superalloys is austenite. In addition, there are cobalt-based alloys, chromium-based alloys and copper-based alloys. High-temperature alloys can be used at temperatures above 1000°C, but their plasticity is poor and difficult to form.
2. Forging of high temperature alloys
Since high-temperature alloys do not undergo phase transformation, the grain size of forgings depends on the degree of forging deformation. The critical deformation degree of high-temperature alloys has a wide range, which can be between 0.5% and 20%. Therefore, the deformation degree of each time cannot be lower than the critical deformation degree. Due to the low plasticity of high-temperature alloys, corresponding measures need to be taken during the forging process to obtain the required deformation without cracking. It should be noted that high-temperature alloys have high deformation resistance, narrow forging temperature range, slow recrystallization rate and low low-temperature thermal conductivity. Therefore, the following process principles must be understood when forging:
1. Blanking: If the diameter of the blank is less than 25mm, it can be cut by shearing. If the diameter of the blank is larger than 25mm, it can be cut by grinding wheel cutting and mechanical processing. Grinding wheel cutting will produce thermal stress and easily cause cracks at both ends of the blank, so it should not be used in large quantities. In order to meet the requirements of the forging process, mechanical processing methods are often used to cut materials.
2. Heating: High-temperature alloys have higher requirements on heating conditions. Heating specifications and forging temperatures depend on the different materials of high-temperature alloys.
3. Forging: Regardless of whether drawing or upsetting is used, the following process characteristics and requirements must be understood during model forging. The upper and lower V-shaped anvils need to be used for elongation. For some high-temperature alloy ingots with low plasticity, the upper and lower semi-arc anvils should be used for elongation to improve the stress state of the material and reduce the occurrence of cracks. In order to achieve uniform deformation during upsetting, paper coated with glass lubricant can be used to pad both ends of the upsetting blank; for forgings with larger D/H, stack forging is used, and carbon steel is used as a soft pad to pad both ends of the forging. end. The blanking die chamber, upsetting die chamber and final forging die chamber for the last upsetting of high-temperature alloys should be set separately, and the billet must be preheated in each step to reach a certain forging temperature to ensure the smooth progress of forging.
4. Cooling: High-temperature alloy forgings require appropriate cooling treatment after forging to eliminate residual stress and improve the organizational structure. Commonly used cooling methods include air cooling, water cooling and oil cooling. The air cooling speed is slow and the effect is poor; the water cooling speed is fast, but it can easily cause deformation and cracks of the forgings; the oil cooling speed is moderate, which can make the forgings achieve better organizational structure and performance, but care needs to be taken to prevent oil contamination.
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: Dec-22-2023
