Metal weldability and its test methods Zhengzhou Guoyun High Frequency Welding Equipment | High Frequency Machine Tool Guide Hardening Equipment | High Frequency Heating Equipment Website: www.guoyunwu.com www.zzzpl.com www.zzgpl.com In principle, all kinds of metals can be high-frequency welded. However, the inherent basic properties of the metal itself cannot directly indicate what problems may occur during welding and whether the seam performance after welding can meet the usage requirements. Therefore, the adaptability of metal materials to welding processing is measured by weldability. 1. Welding Concept The weldability of metal refers to the ease or difficulty of obtaining a high-quality welded joint under certain welding process conditions, including gear brazing tool welding equipment. Problems that may arise when workpieces undergo annealing and normalizing.
Quenching technology is widely used in modern mechanical manufacturing industry. Important parts in machinery, especially steel parts used in automobiles, airplanes, and rockets, are almost all treated with quenching. To meet various technical requirements for different parts, various quenching processes have been developed. For example, according to the part being treated, there is overall quenching, partial quenching, and surface quenching; according to whether the phase transformation is complete during heating, there is complete quenching and incomplete quenching (for hypoeutectoid steel, this method is also called subcritical quenching); according to the content of phase transformation during cooling, there are分级 quenching, isothermal quenching, and sub-speed quenching, etc. Its content includes two aspects: one is the sensitivity of metal to defects when subjected to welding processing, i.e., process weldability; the other is the ability of the welded joint to reliably operate under service conditions, i.e., service weldability.
1) Process Weldability
Process weldability is a relative concept. If a metal can be welded under very simple process conditions to obtain a good joint that meets the usage requirements, it can be said to have good weldability. Conversely, if complex process conditions must be ensured, such as high-temperature preheating, complex heat treatment after welding, or if the welded joint does not perform well enough to meet the requirements, it can be considered to have poor weldability. Process weldability refers to the ability of a metal to obtain a high-quality welded joint under certain process conditions. It is not an inherent property of the metal itself but changes with the change of welding conditions.
2) Service Weldability
Service weldability refers to the extent to which the entire welded joint or the overall structure meets the technical conditions specified for use performance. This includes mechanical properties, notch sensitivity, corrosion resistance, etc.
2. Weldability Test Methods
The methods for evaluating weldability are varied, and each test method examines or explains weldability from a specific perspective. Therefore, a series of tests are often required to comprehensively explain weldability, thereby helping to determine the welding method, welding material, process specifications, and necessary process measures.
The main contents of weldability testing include: hot cracking test, cold cracking test, brittleness test, service performance test, etc. The implementation methods are divided into three categories: simulation, actual welding, and theoretical calculation. The most commonly used methods are the inclined Y-groove crack test, plug test, rigidly fixed butt crack test, variable restraint crack test, carbon equivalent method, etc.
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