The cold rolling of seamless steel pipes transforms martensite into seamless steel pipes before the rolled pieces enter the finish rolling extruder. Rough rolling is still carried out under full martensite conditions. Then, according to the ultra-fast refrigeration system between the fine extruder and the rough extruder, the temperature of the hot-rolled strip is lowered below the change point before entering the first fine extruder.
The nitriding treatment method of seamless steel pipes mainly adopts a nitriding furnace. The seamless steel pipe is put into the material frame, and then the product workpiece driven by the lifting is put into the furnace bottom to be heated. In addition, a nitriding furnace with a furnace door lifting load design scheme can also be manufactured, and the workpiece of the vertical wall-mounted product can be heated according to the lifting and wall-mounted special tools. The furnace shell of the nitriding furnace is generally driven by a geared motor, which is an electric fully automatic elevator. After the furnace cover is closed, another anchor bolt is clamped to ensure the tightness of the vacuum pump of the nitrogen furnace. Vacuum packaging first, then heat treatment in N2 nitriding.
Nitriding treatment of seamless steel pipe refers to the method of organic chemical heat treatment on the surface of the workpiece produced by organic chemical heat treatment at a certain temperature. Nitriding Furnace Nitriding furnace is used for steam nitriding heat treatment process for various steel machinery parts, automobile curved glaze, transmission gears, motorcycle brake pads, mold shells, etc. In the field of non-ferrous metal sheets, it can be used for bright air-free oxidation quenching of copper materials such as air-conditioning copper pipes, copper coins, copper core wires, copper rods, etc. in a maintenance atmosphere. Or for thick-walled seamless steel pipes, short shafts and various metal material parts, the air-free oxidation quenching heat treatment method under vacuum pump N2 maintenance conditions is adopted.
Obviously, since the heating temperature of the cold-rolled slab in the seamless steel tube zone is lower than that of the basic cold-rolled, heating energy consumption can be greatly reduced, and the production capacity of the heat treatment furnace has also been improved. The lower heating temperature can also reduce the heating of the hot-rolled strip, thereby reducing the fatigue cracking and cracking of the hot-rolled strip caused by internal stress, and reducing the wear of the hot-rolled strip; ultra-low temperature cold rolling can also reduce secondary zinc powder, Improving the process performance of hot-rolled products can also increase the operating speed of the pickling passivation line. Life practice has proved that replacing the traditional cold-rolled and quenched hot-rolled strip with hot-rolled thin strip produced in the hot-rolled seamless steel tube area can greatly reduce product costs.
