Application of heat treatment energy saving in production process
The energy-saving aspects of heat treatment are mainly composed of several factors:
1) Whether the heat treatment process is effective to make the processed workpiece meet the technical requirements of its design, and at a lower cost.
2: Whether heat treatment equipment has been effectively and reasonably used in operation, such as continuous production, equipment waiting time reduced. And there is no additional heat loss.
3: Whether heat treatment operators, process technicians and production managers communicate well or not, everyone can effectively manage and organize production.
1. Heat treatment process:
In traditional process calculation time: T = K*A*D is heating time, K is charging coefficient, A is heating coefficient, D is effective thickness of workpiece. In fact, in actual production, we usually calculate holding time according to past working experience and effective thickness of workpiece. In large quantities, according to actual experience or observing the fire color of workpiece, this mainly reflects on carbon steel and low alloy steel. This is because carbon steel has no alloying elements and carbides, and does not need long time homogeneous austenitizing process. Because the heat transfer coefficient of low alloy steel is basically similar to that of carbon steel, the heat transfer time of workpiece is mainly determined by its effective size. For the workpiece in production, when the furnace temperature has reached the process setting value, that is to say, when the workpiece surface has reached the process temperature value, the workpiece has been burned through, and no additional heat preservation time is needed. This is what we often call "zero" heat preservation addition. Heat. For mass production, we usually heat the furnace first, then put the workpiece into the temperature, and when the furnace temperature reaches the process time again, then add a certain homogenization time, which can relatively shorten the process cycle, save energy and reduce costs.
Alloy structural steel (40Cr, 35CrMo, 42CrMo) and so on, because some alloying elements are added to the material, it takes a certain time to homogenize the carbide during the heating process, so it takes a little more time than carbon steel. Generally, we also need about 60%-80% of the traditional process time. This can shorten the heating time of steel parts at high temperature and reduce the deformation amount relatively. One point is that the austenitized grains are relatively small. After quenching, fine martensite structure can be obtained, and its mechanical properties can be improved to a certain extent. This is also the effect that our heat treatment workers want to achieve.
2. Furnace Loading of Parts
1: In actual production, when the number of workpieces is limited, it is not cost-effective to arrange stoves separately. In this case, we can mix different workpieces and different materials into one stove under the same technological parameters, such as Cr12MoV and 8407 or H13, 40Crand 42CrMo. The quenching temperature is roughly the same, so that the furnace loading can be satisfied. Similarly, when the tempering temperature is the same, different parts and materials can be mixed in one furnace, and the tempering time can be carried out according to the longest tempering time.
2: Heat treatment fixture, in fact, many of our company's products are not the same, but the quantity is not very much, but in order to reduce the deformation, sometimes in order to increase heat treatment tooling, so I often do not use heat-resistant stainless steel, mostly replaced by ordinary low carbon steel, mainly low material prices, there are not many.
3, heat treatment cooling medium
Because many of our company's mechanical parts are alloy structural steel, so when considering quenching medium. I choose in aqueous solution, aqueous quenching will avoid large diameter carbon in low alloy steel in oil quenching heat treatment hardness value may be short of, water quenching cracking situation, synthesis of water-soluble quenching liquid is especially suitable for low and medium carbon steel induction quenching and bulk, water-soluble synthetic quenching liquid is especially suitable for low, medium carbon steel induction quenching and bulk, by adjusting the concentration and so on, can get different cooling speed, quenching workpiece light and have short-term anti-rust effect, don't wash drawing directly, without the smell of cooking. No oil smoke, no combustion, no fire hazard, improve the working environment. Not easy to aging, deterioration, long service life, relative to oil. The cost is also relatively low.
4, tempering process: tempering process is according to the parts of the tempering temperature to decide to use the furnace heat, general rules is part tempering temperature is lower than the furnace waste heat temperature of 300 degrees or so, so charging quickly reach the stove after tempering process of workpiece temperature set point, and tempering is better than a tempering for many times, when mass production so that the secondary tempering the organizational performance is better than a tempering, cost is also reduced a lot.
5, equipment maintenance and maintenance: we need to regularly repair equipment in production, check the sealing of the furnace, furnace door. The related instruments and meters of the distribution box should be calibrated and maintained regularly to reduce the loss caused by the shutdown of the furnace due to electrical faults. The maintenance of relevant operating equipment, such as the trolley, reduces the loss caused by inconvenience in and out of the furnace.
6, heat treatment quality control: in fact in the heat treatment of workpiece, its itself is in energy saving, an artifact if without effective and reasonable heat treatment, that the parts would not be a long using time, premature failure of the parts be sure to make new parts to replace, and this will clear the consumption of raw materials and machinery processing time, and other related fees. Effective and reasonable heat treatment can make the service life of workpiece increase exponentially. Therefore, good quality of heat treatment can avoid early failure of the workpiece, can avoid the workpiece heat treatment repair (normalizing, re-quenching tempering, correction, de-stress tempering) and a series of procedures. So our country in the 1970s has a slogan: "do well in heat treatment, top several parts".
Heat treatment energy saving is often related to process management, reasonable arrangement of work, reduce the down time, the furnace heating time stage in the time stage of cheap electricity, a lot of times the process implementation in place is related to management, the company should strictly formulate the process procedures and equipment operating standards, and related technical standards. In terms of production arrangement, the batch should be produced at full load as far as possible, and the batch should be put together if the furnace capacity is not enough, and the preparation for various heat treatment works should be made in advance. Check the operation of heat treatment equipment regularly.
Actively improve the heat treatment personnel's professional level, operation level and related work consciousness, improve the attitude of heat treatment personnel. Because a lot of times the ultimate determinant is people. When the relevant hardware cannot be changed, the working attitude of the staff is software. We can formulate relevant systems, implement regulations on rewards and punishments, collect statistics and assess energy consumption in production, and carry out rectification management against defects.
Energy-saving emission reduction in our work is in a very important position, how to save energy, improve production efficiency, reduce costs, in the market competition to establish their own brand. The improvement of production and technical management is an important measure to carry out the development of science and technology. Energy conservation consciousness starts from me, starts from now, starts in the work bit by bit. Heat treatment technology to achieve the goal of energy saving, emission reduction, high quality, high efficiency. Also make the product quality, cost control in the market in a certain level.