Introduction to the hardness of cylinder tubes

- Mar 23, 2020-

Hot-rolled cylinder tubes are made by continuous casting of round tube slabs or preliminary rolled slabs, which are heated by a walking furnace, descaled by high-pressure water, and enter a rough rolling mill. After the rough rolling material is cut and processed at the tail end, it enters the finishing mill. Computer controlled rolling. After rolling, it is cooled by laminar flow and coiled by a coiler to become a straight hair coil. The head and tail of a straight hair bun are usually tongue-shaped and fish-tailed, and their thickness and width accuracy are poor. Straight hair curls are often corrugated, folded, and tower-shaped. The coil is heavy, with an inner diameter of 760mm. After the straight hair coil is processed by cutting head, tail, trimming, multi-pass straightening, straightening, recutting or rewinding, it becomes hot rolled steel sheet, flat hot rolled steel coil, slitting tape and other products. If scale is removed by pickling and oiling, hot-rolled finished coils will be hot-rolled pickled coils.

As we all know, cylinder tubes belong to hollow long round steel and are widely used in various industries. However, despite the large number of users, little is known about the hardness of cylinder tubes. Here, let's take a closer look at three different cylindrical tube hardnesses.

First: Rockwell hardness.

The Rockwell hardness test of the cylinder tube is basically the same as the Brinell hardness test. The indentation test method is different from the Rockwell method, which is mainly used to measure the indentation depth. The Rockwell hardness test method is the most widely used method because Rockwell hardness is suitable for testing soft metal materials, which effectively makes up for the shortcomings of the Brinell hardness test, and the method is relatively simple. However, because the indentation is small, the hardness value is not as accurate as the Brinell hardness value.

First: Brinell hardness.

Brinell hardness is the most widely used standard test in the entire cylinder tube. Its indentation is often used to indicate the material's main hardness. Not only is it intuitive, it is also very convenient. However, this method is not applicable for hard or thin steel.

Third: Vickers hardness.

This hardness test, or indentation test, is more suitable for thin metals or materials with higher surface hardness. Rockwell hardness has dual advantages, Brinell hardness, and overcomes the disadvantages of the two hardness tests, but there is no simple Rockwell hardness test. The high hardness of Vickers hardness and Vickers hardness are required for the conditions of steel pipes.

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