The hottest new grade steel 0 that can improve die

2022-08-08
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A new grade steel that can improve the performance of molds

most injection molds are made of traditional steel grades, such as AISI P20. However, recently, a steel grade superplast that can replace AISI P20 has been developed. Due to the innovative metallurgical technology, this grade has obtained completely different properties from AISI P20. For mold manufacturers, this development breaks the inherent selection range of mold materials, which can better meet the special needs of the plastic industry

traditional steel can improve its properties by combining carbon with other hard elements such as chromium and molybdenum. Although this method has achieved satisfactory results in the past few decades, with the continuous emergence of new polymers in the market and the expanding demand for molds, these materials begin to show some limitations: close inspection shows that the hardness of all thick parts will decline, which is unacceptable in application

more seriously, mold manufacturers will face various problems in processing, such as high hardness points in rotating holes, strong vibration in milling and so on. Therefore, carbon based metallurgical technology is no longer the best choice. Mold manufacturers need to reduce internal costs to remain competitive. In order to achieve continuous success, they have to minimize risks in the manufacturing process. For mold manufacturers and processors, choosing an improved steel grade is one of the ways to solve the above problems

challenge carbon content

since carbon is one of the weaknesses of P20 type steel, a solution is to limit the carbon content as much as possible, and this reduction in composition must first be supplemented by adding expensive alloy elements, such as nickel, chromium or molybdenum

using boron smelting technology, only a small amount of boron can be added to obtain the same effect as adding expensive alloy elements. This technology can make the hardness of steel reach 300 Hb, and has excellent uniformity. Even if the thickness of parts reaches 800mm, there is no problem. After several years of research and optimization, this technology is becoming more and more mature, which led to the birth of this improved steel grade (see Table 1 and figure 1)

Figure 1 Hardness of new steel

effect of boron smelting

because smelting is only a way, what we are most interested in is whether it can replace some foreign fixtures to a certain extent or what it can achieve

1. Machinability

the first argument for using steel with reduced carbon content and pre hardened to 300hb is the improvement of machinability and the reduction of related costs

the rough machining time is shortened by 33% by using an automobile fender mold for the test. The traditional steel needs to be processed for 60H, while the new grade steel only needs to be processed for 40H. The end result is a reduction in machining costs (see Table 2 and Figure 2)

Figure 2 Comparison of chip removal rate

according to the specific algorithm, only the experimental impact resistance quality level of the test in this experiment can be determined. 2. Uniformity

improving the uniformity is another advantage. On the one hand, the hardness in the middle of the part has not decreased, and more importantly, high hardness points will not be encountered when turning the hole, and surface defects will not appear in chemical corrosion and polishing

high hardness points are areas with high carbon content, which are formed during the solidification of liquid steel. The advantages of low carbon steel are obvious. These high carbon points are harder than other places, which will cause the deviation of the polished surface and produce defects, especially on large-area surfaces, which are more clearly visible

the improvement of homogeneity in Figure 3 excludes high hardness points, so it will not cause surface defects during chemical corrosion and polishing

this type of defect is more obvious after spraying, which will directly affect the quality of injection molded products. The use of low-carbon and pre hardened to 300 HB steel grade manufacturing molds to produce body panels can make the surface of products more perfect

3. Weldability and thermal conductivity

compared with the traditional P20 grade, the improved steel improves the weldability and increases the thermal conductivity by 15% - 20%. The improvement of heat conductivity can significantly shorten the molding cycle. However, when the thermal conductivity of plastic itself is poor (the thick part of the product), the development of plastic and steel automobile, household appliances, lighting and other markets makes the contact area of modified plastic consumption increase year by year small (flat products), or some problems related to cooling channels and blockage appear, this advantage will be discounted

when mold manufacturers and processors look for suitable mold materials to improve performance and reduce costs, paying attention to the processing performance, uniformity, weldability and thermal conductivity of materials is the key to find the correct answer. Improved low-carbon (boron replaces carbon) and pre hardened to 300hb steel can provide today's mold manufacturers with the benefits they are seeking

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