The Significance of Creep Testing
|28.1.2021||Posted by tactical33 under Advertising & Marketing|
The creep phenomenon of metal materials has been discovered for a long time. As early as 1905, special inspectors began to conduct special tests on the creep properties of metal materials. Initially, researchers only studied low melting point pure metals, such as Lead and zinc, because these metals show significant creep at room temperature. Subsequently, began to gradually study the creep phenomenon of pure metals such as aluminum and magnesium with higher melting points, and finally extended to the iron, nickel, and even refractory metals tungsten and platinum. Modern creep testing research mainly focuses on pure metal research and research on iron, cobalt, nickel-based alloys and various other high-temperature alloys. For these alloys, they need to exhibit significant creep at a high temperature of several Baidu (for example, carbon steel>0.35Tm, stainless steel>0.4Tm).
In fact, in the early days, people knew little about the strength of metal materials. When designing metal parts, only short-term strength is used as the design basis. Even if the stress is lower than the elastic limit, many components will still fail due to plastic deformation or failure due to breakage after a period of use. With the development of science and technology, the use temperature of metal materials has gradually increased, and this contradiction has become increasingly prominent. This led to a further understanding of the relationship between material strength and duration of use, which led to the development of long-term strength studies of metallic materials, such as creep, creep rupture, relaxation, fatigue and fracture mechanics. Creep is one of the earliest studies, with richer content and more significant results, and it has become the basis of several other research fields.
Metal undergoes slow plastic deformation under sustained stress (even at temperatures well below the elastic limit). Metals with lower melting points are prone to this phenomenon; the higher the temperature of the metal, the more obvious this phenomenon. At a certain temperature, the phenomenon that metals undergo slow plastic deformation due to continuous stress is called metal creep. This stress that causes creep is called creep stress. Under this continuous stress, the creep deformation gradually increases and eventually leads to fracture, which is called creep fracture. The initial stress that causes the fracture is called the metamorphic fracture stress.
In some cases (especially in engineering), when discussing as an indicator of material strength under specific conditions, creep stress and creep rupture stress are often referred to as creep strength and creep rupture strength. The latter is also called permanent power. The occurrence of creep is the result of a combination of temperature and stress. The mode of action of temperature and stress can be constant or variable. The traditional creep test is specially used to study the creep behavior under constant load and constant temperature. In order to distinguish changes, this test is called a static creep test.
The above is just some basic common sense of the creep performance test of metal materials. The research of creep phenomenon is closely related to the development of industrial technology. As the working temperature increases, the phenomenon of material creep becomes more and more obvious, and the creep strength of the material becomes higher and higher. Different working temperatures require materials with different creep properties, so creep strength has become an important factor in determining the use value of high-temperature metal materials.
T, C&A Lab performs the creep test in accordance with industry standards and specifications, including ASTM and ISO standards. Its creep testing capabilities include, but are not limited to welding, polymers and adhesives. In addition, the experts in the company’s Creep Testing Laboratory also provide a variety of custom tests, for example Abrasion & Wear Testing, Bending Testing, Creep Testing, Fastener Testing, Fatigue Testing, Fracture Testing, as research needs and standards.