Why the quenching temperature of black steel seamless pipe is low

Posted by chase Liu on April 13th, 2023

Seamless black steel pipe is uncoated steel, also known as black steel pipe. The dark color comes from iron oxides that form on its surface during the manufacturing process. When steel pipe is forged, a black oxide scale forms on its surface, giving it the finish seen on this type of pipe.

The temperature specified in the quenching process of black steel seamless pipe is relatively high. The specified temperature ranges from nearly 100 degrees to thousands of degrees, and the characteristics and advantages of black steel seamless pipes can be displayed more critically under high temperature and high pressure. It can resist high temperature and high pressure in use, and is generally used in many engineering buildings. However, the temperature specified in the quenching process of black steel seamless pipes should not be too high, and quenching at too high a temperature will cause various damages. In most cases, the black steel seamless pipe will have cracks, so the quenching temperature of the black steel seamless pipe should not be too high.

The overheating condition of the quenched microscopic structure can be observed from the rough edge of the black steel seamless pipe. To accurately discern the level of its hyperthermia, it is necessary to closely examine the structure in a microscope. If coarse fibrous austenite appears in the quenched structure of GCrl5 steel, it is a quenched overtemperature structure. Excessive quenching and heating temperature or too long heating and heat insulation time will lead to all-round overheating of black steel seamless pipe. It may also be because the initial structure with striped cementite is relatively serious, and some austenite fibers are thick in the low-carbon environmental protection zone between the two zones, resulting in partial overheating. The residual martensite in the over-temperature structure of black steel seamless pipe increases, and the specification reliability decreases. Due to the overheating of the quenching structure and the thick crystallization of the black steel seamless pipe, the core performance of the black steel seamless pipe is reduced, the impact resistance is reduced, and the service life of the black steel seamless pipe is also reduced. Serious overheating can also lead to quenching cracks.

In the case of quenching, the black steel seamless pipe should pay attention to the temperature and maturity to ensure that the characteristics and functions of the black steel seamless pipe can be brought out smoothly, otherwise the characteristics of the black steel seamless pipe will not be easy to play well.