Problems and Countermeasures in the process of stainless steel grinding
Author: ComeFrom: Date:2017/8/22 14:46:12 Hits:314
In order to achieve the surface quality and machining accuracy, the stainless steel parts are usually machined by grinding. Because of the great toughness, low thermal conductivity and small elastic modulus of stainless steel, the following problems often exist in grinding: 1) the grinding wheel is easy to adhere and block; (2) the surface of the machining is easy to burn; 3) the work hardening is serious; 4) the workpiece is easy to deform.
From the above we can see that the choice of grinding wheel and grinding fluid directly affects the grinding efficiency and machining accuracy. In this paper, the factors that affect the adhesion, blockage and surface roughness are studied experimentally.
1 the influence of particle size of grinding wheel on adhesion rate.
Four wheel with white jade, hardness K and particle size were 36, 46, 60, 80, on the test piece in cylindrical longitudinal grinding, grinding length is 600mm, the detection rate of adhesion, the grinding wheel is finer, the adhesion is more serious, this is due to the abrasive between hole grinding cutting the chip can be stored in the cavity; and the grinding wheel is thinner, smaller hole, wheel quickly lose chip space, causing blockage.
2 Effect of grinding wheel hardness on adhesion rate.
The grinding wheel is made of white corundum, particle size 46, hardness of H, J, K and L, grinding of specimens, grinding stroke 600mm, adhesion rate detection. The higher the hardness of the grinding wheel, the more serious the adhesion. This is due to the low hardness of the grinding wheel, abrasive particles in the grinding force, easy to fall off the surface of the grinding wheel, forming a new chip space, is not easy to plug.
3 Effect of abrasives on adhesion rate.
The common abrasive wheels are two kinds of white corundum and green silicon carbide. The experimental results show that the influence of two kinds of abrasives on adhesion rate is little difference. Green silicon carbide can slightly reduce adhesion phenomenon, because it is crisp and sharp.
Effect of 4 grinding fluid on surface roughness.
Using three kinds of emulsion, inorganic salt and oil base fluid grinding grinding fluid, adding sulfur, chlorine and other extreme pressure additives, observe the surface roughness of the workpiece after machining, grinding fluid flow is 20L/min, grinding stroke is 600mm, the experimental results are shown in table 3.
It can be seen that the surface tension is small and contains extreme pressure additives, and the surface quality obtained by grinding is good. The reasonable use of grinding fluid can improve the heat dissipation condition. The grinding fluid can remove the grinding debris and the falling abrasive particles. At the same time, the oil film is formed on the metal surface to lubricate and reduce the surface roughness of the workpiece.
5 Effect of grinding amount on adhesion rate.
The workpiece speed, feed rate and grinding depth have little effect on the processing. As can be seen from table 1 and 2, the change of grinding depth has little effect on the adhesion rate.
Finally we come to the conclusion that..:
When grinding stainless steel, reducing the adhesion of the grinding wheel is an important factor to improve the grinding efficiency, and the grinding wheel should be often trimmed to keep the cutting edge sharp.
2) grinding stainless steel grinding wheel, choose the sharp grinding wheel is the main goal, generally choose low hardness grinding wheel, the effect is good, but also can't choose too low hardness, otherwise, abrasive not blunt, will fall off. J class is recommended.
3) in order to reduce the adhesion of the grinding wheel, the coarse grain grinding wheel should be selected. 36 and 46 grit sizes are used for coarse grinding, and 60 size is selected for fine grinding.
4) GC grinding wheel can improve grinding efficiency when grinding stainless steel.
5) grinding fluid selection must take into account the two roles of lubrication and cleaning, adequate supply, you can choose a small surface tension, extreme pressure additives emulsion, high surface quality can be obtained.
6) the selection of grinding parameters can be determined according to machining allowance.
7) during the experiment, it is found that the microstructure and bonding agent of grinding wheel have certain influence on the grinding process of stainless steel. At present, it is limited by experimental means and needs further study.