1. Dimensional stability. For high-precision seamless carbon steel pipes, high precision is required, so dimensional stability needs to be maintained. Due to straightening in air, the cooling rate is slow, so it has a stabilizing effect on austenite. It will increase the amount of retained austenite in the structure, so cold treatment is required.
2. Reduce quenching deformation. Due to the slenderness of the ms seamless tube, it is easy to deform during the quenching process, so its deformation should be strictly controlled. Heat treatment is a very critical process. In the process of quenching and cooling, timely straightening by using the plasticity of supercooled austenite is a key step to ensure the improvement of its pass rate. For this purpose, hot bath quenching or cooling in oil for a certain period of time should be carried out to bring out thermal calibration.
3. High hardness. The seamless steel pipe mainly bears the contact fatigue load, so it has high hardness, so it should be quenched or surface quenched or chemical heat treatment, etc., and then be tempered at low temperature.
In order to safely cut thick-walled seamless steel pipes, the following operations are recommended.
1. Mechanical cutting adopts two methods: exterior and interior. It uses the turning tool principle to cut and bevel the nozzle. The single machine has a large span and can process large thicknesses with less waste. The processing process does not generate high temperature, does not affect the pipe, and is conducive to welding. Water cutting processes the pipeline through the combined action of a high-pressure pump and emery. The incision is clean and the processing span is large, but the efficiency is low, and the processing thickness is severely limited.
2. Oxygen C2H2 flame cutting, by adjusting the oxygen valve [gate and C2H2 valve, changing the mixing ratio of oxygen and C2H2, three different flames are obtained: neutral flame, oxidation flame and carbonization flame.
3. Ion cutting and plasma cutting can use different working gases to cut various metals that are difficult to cut by oxygen cutting, especially non-ferrous metals (stainless steel, aluminum, copper, titanium, nickel), and the cutting effect is better: the main advantage is the cutting thickness When the metal is not large, the plasma cutting speed is fast, especially when cutting ordinary carbon steel sheets, the speed can reach 5~6 times that of the oxygen cutting method, the cutting surface is smooth, the thermal deformation is small, and the heat affected zone is small.
Read more : seamless black steel pipe