Why does a500 rectangular tube have brittle fracture?

A500 rectangular tube is a name for square tubes and rectangular tubes, that is, steel tubes with equal and unequal side lengths. It is made of strip steel after process treatment. Generally, the strip steel is unpacked, flattened, crimped, welded to form a round tube, and then rolled into a square tube from the round tube and then cut to the required length. Widely used in machinery manufacturing, construction industry, metallurgical industry, agricultural vehicles, agricultural greenhouses, automobile industry, railway, highway guardrail, container skeleton, furniture, decoration and steel structure fields, etc. So, why does a500 rectangular tube suffer from brittle fracture?

Reasons for brittle fracture of a500 rectangular tube

The pickling solution used in the a500 rectangular tube pickling process is generally a mixture of various acids, mainly sulfuric acid, nitric acid and hydrofluoric acid. These mixed acids are highly corrosive and oxidizing, and the temperature of the corrosive medium is relatively high, which puts forward high requirements on the corrosion resistance of anti-corrosion materials.

There are many anti-corrosion materials suitable for a500 rectangular tube, among which the best one for seamless a500 rectangular tube is epoxy resin and its modified resin. The pickling principle of a500 rectangular tube is to use acidic liquid to remove the oxide skin on the surface of a500 rectangular tube after pretreatment, remove the metal ions on the surface, and make it have a beautiful finish. Pickling material forms include belt washing, tube washing, plate washing, line washing, etc., due to defects such as cracks in the hot-rolled tube billet or after the high-precision cold-drawn tube is made into an oil cylinder. Fractures that occur during use have almost no plastic deformation, and are generally brittle fractures.

Brittle fractures are caused by a variety of reasons. For example, when there are precipitates on the grain boundary, no matter whether its strength is stronger or weaker than that of the matrix, it is the cause of cracks. The segregation of inclusions on grain boundaries is also the cause of fracture. In addition, even under the action of alternating load far less than the yield limit, fatigue fracture will occur. During low-stress brittle fracture that occurs in high-strength metallic materials, the material structure is far from homogeneous and isotropic. When the a500 rectangular tube is used reasonably to clean the rusty pipe fittings, it can ensure that the pipe fittings can serve the production for a long time and create more production benefits.

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