The influence factors of machine tool castings of high strength cast iron is what

Traditional grey cast iron smelting control direction is low carbon high strength cast iron (C: 2.7 ~ 3.0, Si: 2.0 ~ 2.3, Mn: 0.9 ~ 1.3), although this material can meet the requirements of material mechanical properties, but its casting properties, processing performance is poorer, along with the market development, more and more difficult, high technical quality requirements into CSMF production sequence casting products, especially labor frequency electric furnace melting process instead of the cupola melting process, how to achieve high carbon equivalent under the condition of the electric furnace smelting high strength cast iron, meet the requirement of the customer's order, and we were then a research topic, this paper describes the electric furnace smelting under the condition of high strength gray cast iron production technology.

The influence factors of high strength cast iron has the following the price

A, carbon equivalent effect on the properties of materials

Main factors determine the properties of gray cast iron graphite morphology and the performance of the metal substrate. When the carbon equivalent (CE = C + 1/3 si) is higher, the increase in the number of graphite, the breeding condition is bad or have harmful trace elements, the graphite shape. Such graphite effective area of base metal to withstand the load decreases, and when the load to produce stress concentration phenomenon, make the strength of the metal substrate can not play normally, thereby reducing the strength of the cast iron. Pearlite in the material has good strength, hardness, and the intensity of ferrite is quality, and the bottom is soft and low. As the amount of C, Si, reducing the the pearl size, ferrite content increased. Therefore, the increase of carbon equivalent in two aspects of graphite shape and matrix organization affect the tensile strength of cast iron castings and casting hardness of entities. In the smelting process control, material properties of carbon equivalent control is to solve a very important factor.

Second, the influence of alloy elements on the properties of ceramic materials

In the alloy elements in grey cast iron is mainly refers to Mn, Cr, Cu, Sn, Mo, etc to promote pearlite generated elements, these elements will directly affect the content of pearlite, at the same time because of the addition of alloy elements, to a certain extent of graphite, reduce the amount of ferrite matrix and even disappeared, pearlite are refined in the certain degree, and with a certain amount of ferrite alloy element and solid solution strengthening, always makes cast iron has high strength performance. In the smelting process control, control of the alloy is equally important.

Three, the influence of furnace charge ratio on the material

In the past we have always been committed to conform to the requirements of the specification as long as the chemical composition should be able to get up to the standard mechanical properties of the material point of view, but in fact this view can see only the conventional chemical composition, and ignore some of the alloying elements and harmful elements in the role. Such as pig iron is the main source of Ti, so how much pig iron usage will directly affect the material, the content of Ti in produce very big effect on the material mechanical properties. As scrap steel is the source of many of the alloying elements, so the effect of the mechanical properties of the cast iron scrap amount is very direct. At the beginning of the furnace put into use, we used the cupola furnace charge ratio (pig iron: age from 25 to 35%, scrap: 30 ~ 35%) the results of material mechanical properties (tensile strength) is very low, when we realize the use amount of scrap will have an impact on the performance of the cast iron after adjust the amount of scrap steel, problem solved quickly, so scrap steel in the process of melting control is a very important control parameter. So the ratio of furnace charge for has a direct influence on the mechanical properties of the cast iron material, is the focus of the smelting control.

Four, the influence of trace elements on the properties of ceramic materials

In the past we only pay attention to the traditional five elements in the process of melting of cast iron material, the influence of the effect on other trace elements is just a qualitative understanding, but seldom discuss quantitative analysis to them, in recent years, due to the evolution of foundry technology, melting equipment constantly updated, cupola has been gradually replaced by electric furnace. Electric furnace smelting is the cupola incomparable advantage, but the cupola smelting electric furnace melting also lost some of the advantages, so that the influence of some trace elements in cast iron is reflected. Because of metallurgical reactions in cupola is very strong, is in the charge is in strong oxidizing atmosphere, the vast majority was oxidized, together with the slag discharge, only a few will remain in the molten iron, so some have adverse effects on the casting of the metallurgical process of trace element by cupola, usually does not lead to adverse influence on the formation of cast iron. In the process of cupola melting, coke in nitrogen and nitrogen (N2) at high temperature in the air, part of the decomposition will dissolve in the molten iron in the form of atoms, made of nitrogen content in molten iron is relatively high.

According to statistics, since the furnace put into production, due to high levels of lead scrap and due to the lead content is too high can't adjust the scrapping of the more than one hundred tons of hot metal and the number of nonconforming product due to lack of nitrogen content is quite high, also caused great economic losses.