Heat treatment refers to the material in the solid state, through the means of heating, insulation and cooling, in order to obtain the expected structure and performance of a metal thermal processing process. Metal heat treatment is one of the important processes in mechanical manufacturing, compared with other processing processes, heat treatment generally does not change the shape of the workpiece and the overall chemical composition, but by changing the microstructure of the workpiece, or change the chemical composition of the workpiece surface, give or improve the performance of the workpiece. Its characteristic is to improve the inherent quality of the workpiece, which is generally not visible to the naked eye.
Usually in the heat treatment process, how to grasp the processing time, how to do the workpiece heat treatment effect is just right, and do not let energy is a technical work. Usually according to the experience of the technical personnel and the thickness of the workpiece to calculate the insulation time, mass production according to the actual experience and observe the color of the workpiece in the fire. Mainly reflected in carbon steel and low alloy steel, carbon steel without alloy elements and carbides, no time insulation. The heat transfer coefficient of low alloy steel is similar to that of carbon steel. When a single product heat treatment processing, when the furnace temperature reached the process set value, the workpiece has been burned through, there is no need to add additional insulation time, that is, we often say "zero" insulation heating.
What is the specific method to reduce the cost in the heat treatment process? Its specific performance is as follows:
1. In mass production, the furnace is usually heated and the workpiece is put into the furnace after reaching the temperature. After reaching the process time again, the workpiece is homogenized for a certain amount of time, which can relatively shorten the process cycle and save energy and reduce cost. There are alloy elements in the alloy structural steel material, and it is necessary to homogenize the carbide for a certain period of time in the heat treatment process, which is longer than that of carbon steel.
2, tempering process according to the tempering temperature of parts, usually according to the experience of the use of furnace heat, parts tempering temperature is lower than the furnace heat temperature of about 300 degrees, the furnace soon reached tempering process temperature value after the workpiece into the furnace. Multiple tempering is better than one tempering. In mass production, the tissue performance obtained by the second tempering is better than that obtained by the first tempering, and the cost is much reduced.
3, the quenching medium choice of aqueous solution, can avoid large diameter carbon low alloy steel oil quenching hardness value can not reach, water quenching is prone to cracking. The water-soluble synthetic quenching solution is suitable for the quenching of low and medium carbon steels, and the concentration is adjusted to control the cooling rate. Quenching workpiece bright and short - term rust, can not be cleaned directly tempering, no soot, not easy to aging and deterioration, long service life, the price is relatively cheap oil.
4, according to the part requirements and conditions, as far as possible to choose a high quenching temperature, reduce the insulation time. For tempering 40Cr round steel (or similar low alloy structural steel), the workpiece can be seen to be quenched by water directly after temperature (box furnace) without cracking.
5. Equipment maintenance and testing should be carried out regularly in production to reduce the loss caused by furnace shutdown caused by electrical faults. Related equipment such as trolley, driving maintenance, reduce the wear and tear caused by inconvenience. The workpiece heat treatment process itself belongs to the energy-saving work, the workpiece has not been through the reasonable heat treatment, the service life of the parts will be very short, the increase of service life is also the embodiment of energy saving.
On 2018-08-08 11:45:46
