Stainless steel parts in order to achieve the surface quality and machining accuracy requirements, usually using grinding processing method. Due to the high toughness, low thermal conductivity and small elastic modulus of stainless steel, the following problems often exist in grinding process:
1) Grinding wheel is easy to adhere and block; 2) The processed surface is easy to burn;
3) Serious work hardening phenomenon; 4) The workpiece is easy to deform.
It is not difficult to see that the selection of grinding wheel and grinding fluid directly affects the grinding efficiency and machining accuracy. In this paper, the factors affecting adhesion blockage and surface roughness are studied experimentally.
2. Experimental conditions and methods
The material of the specimen is 1Gr18Ni9Ti, and its mechanical properties are σb=530MPa, σ=40%, and hardness HB=187. The diameter of the specimen is φ50mm, the length is 300mm, and the surface of the outer circle is finished, and the center hole is punched on both ends. The experiment was carried out on MGB1420 external circular grinding machine with P400×40×203 grinding wheel and external circular longitudinal grinding method. In order to improve the reliability of the test results, repeated tests were conducted to observe the average effect and eliminate the influence of random factors. At the same time, grinding conditions were kept basically unchanged as far as possible. Change the grinding fluid and grinding dosage to examine the effect of grinding.
1) When grinding stainless steel, reducing the adhesion blockage of the grinding wheel is an important factor to improve the grinding efficiency. The grinding wheel should be trimmed frequently to keep the cutting edge sharp.
2) The grinding wheel with good self-sharpening property is the main objective of grinding stainless steel. Generally, the grinding wheel with low hardness has a good effect, but the hardness is not too low, otherwise the abrasive particles will fall off without being blunted. Grade J is recommended.
3) Coarse-grained grinding wheels should be selected in order to reduce the adhesion blockage of grinding wheels. Coarse grinding with 36, 46 particle size, fine grinding with 60 particle size.
4) When grinding stainless steel, GC wheel can improve the grinding efficiency.
5) The selection of grinding fluid must take both lubrication and cleaning into account, and the supply is sufficient. Emulsion with low surface tension and extreme pressure additives can be selected to obtain high surface quality.
6) The selection of grinding dosage can be determined according to the machining allowance.
7) During the experiment, it is found that the structure of the grinding wheel and the binder have a certain impact on the grinding process of stainless steel, which is limited by the experimental means and needs to be further studied.