Friction and wear properties of nodular cast iron plunger pump block

The figure shows the friction coefficient of different parts of lzqt600-3 ductile iron profile. The friction coefficients of the edge, 1 / 2R to the center are about 0.565, 0.612 and 0.611 respectively, and the wear rates are 3.373, 1.337 and 1.679, respectively. The friction coefficient at the edge is low, but the wear rate is high and the wear is serious. The wear degree at 1 / 2R is close to that at the center, which is better than that at the edge. Therefore, it can be inferred that the wear resistance of different parts is in the order of core > 1 / 2R > edge, and there is no difference between the center and 1 / 2R.

The wear resistance of lzqt600-3 ductile iron profile from edge to center is better because in the process of horizontal continuous casting, the cooling rate at the edge of the profile is large, and the austenite is not enough to convert into pearlite fully. However, the cooling rate at 1 / 2R and the core is small, and after a long time, austenite is more fully transformed into pearlite, and the amount of pearlite in these two parts is obviously increased compared with that at the edge. Therefore, it is important to improve the wear resistance of the zl600 profile with high pearlite content and pearlite content.

Similarly, the graphite morphology has a great influence on the wear resistance of three parts of lzqt600-3 ductile iron profile. In nodular cast iron, carbon mainly exists in the form of spheroidal graphite. The wear resistance characteristics of ordinary nodular cast iron are reflected in two aspects. One is that graphite ball is a kind of lubricant with good effect in dry friction movement. The graphite strength is very low when the material is relatively moving, and it is easy to fall off from the matrix. This way plays a lubricating role, so the wear degree of the material will be reduced. Second, when the graphite ball falls off, there are many pits on the surface that can store lubricating oil. In the relative friction, due to the sufficient lubricating oil content, the material also has a good lubrication state, thus reducing the wear of the material. According to the quantitative statistics of Image J software, the number of graphite balls in the center is less than that at the edge, but the content of pearlite is greater than that at the edge, so the wear resistance of this part is the best.