The valve is used in the chemical system air separation equipment, and the sealing surface is mostly made of stainless steel. In the grinding process, due to improper selection of abrasive materials, the grinding method is not correct, which not only reduces the valve production efficiency, but also affects the product quality considerably. According to the characteristics of stainless steel materials, we have chosen to have strong labor intensity and wear resistance, and still affect the product quality after the abrasive grains are broken during processing. In recent years, we have studied the grinding materials, such as white corundum and chrome oxide, and the selection of grinding tools and grinding methods. The particle size is mainly selected from w40, w14, w7 and W5. Four are appropriate. Through the test, and has been promoted and applied in the actual production, it not only improves the quality of the sealing surface, but also improves the production efficiency and obtains good results.
The grinding of the workpiece by the valve firstly sands the grinding tool, and then the grinding process is carried out by means of an abrasive composed of the abrasive particles and the grinding liquid. The grinding force refers to a force acting on a unit grinding surface area, which is a force applied to the lap and applied to the surface to be processed by the abrasive grains. If the pressure is too small, the grinding effect is small and the pressure is increased. The grinding action is enhanced and the grinding efficiency is improved. However, when the pressure is increased to a certain value, the saturation phenomenon occurs, and the grinding efficiency generally reaches a large value. Thereafter, if the pressure per unit area continues to increase, the efficiency decreases.
This is because the valve abrasive has a certain pressure resistance limit, when it exceeds this limit, it will be crushed, the abrasive grains will be finer, and the grinding self-reduction will be reduced. Therefore, when selecting the unit pressure, it should be determined according to the strength and fracture characteristics of the abrasive. After the test, the following parameters should generally be used: 1 In the case of rough grinding, 0.2 to 0.5 MPa is selected for the white corundum abrasive. 3 In the case of fine grinding, select 0.03~0.12MPa for the white jade abrasive.
The grinding speed refers to the speed at which the lap moves relative to the surface of the workpiece. Grinding speed is an important process parameter for controlling the amount of removal, removal speed and surface quality. Figure 2 is a typical relationship between workpiece size removal, machined surface roughness and polishing speed.
The role of the lap and its material lap is to allow the abrasive to temporarily fix and obtain a certain grinding motion, and to transfer its geometry to the workpiece in a certain way. Therefore, the material from which the lap is made should have a long-term retention of the abrasive particles with proper embedding and self-geometry accuracy. Gray cast iron HT200 is an ideal material for making laps. Its structure is composed of hard and wear-resistant cementite, ferrite with good toughness and plasticity, graphite composition, lubrication, and easy molding and processing. .
The grinding time that must be spent to obtain the specified surface quality is greater than the time required to remove the margin. The grinding speed should be appropriately reduced. After testing, the following speed values are suitable: 1 In the rough grinding, the speed of the grinding tool or the workpiece to be ground is 20~50m/min. 2 When the valve is finely ground, the speed of the grinding tool or the workpiece to be ground is 6~12m/min. Surface roughness value selection Surface roughness is one of the main indicators of surface quality. Has a great impact on surface function. It has a direct effect on surface wear, contact stiffness and sealing performance, and affects the product’s performance and life. When different grinding methods and particle sizes are used, the surface roughness achieved is also different.