How to choose Stainless steel pipe texture of material? What elements do you need to look at?
There is a large demand for stainless steel pipes, but how to select them is a problem. In this regard, our stainless steel pipe Factory Zhejiang Hongsheng Special Steel Co., Ltd. teaches you the data. The contents are as follows:
1. First, you should look at its thickness, that is, the specific thickness
2. The second step is to look at the process
3. The third step is to weigh the weight. Stainless steel is a kind of ferroalloy, and the specific gravity of steel is 7.87. Nickel and chromium heavy metals are added in it. The proportion of these metals is larger than that of steel, so the weight is relatively heavy (also refer to the thickness of the plate). If it is fake, poor quality stainless steel, such as steel plate chrome plating weight is light;
4. The fourth step is the most critical step of scraping the surface layer: now JS is running horizontally, and there are many traps. Some stainless steel is actually a layer of steel plate, which is plated with a layer of chromium, and the price is not necessarily cheap. It's a bad trick to use when it's safe.
Change of mechanical properties of tp316h stainless steel tube during tempering
? The quenched microstructure of tp316h stainless steel tube is lamellar martensite and a certain amount of retained austenite. The change law of properties of this structure is different from that of low carbon steel during tempering. When flaky martensite is tempered at low temperature (< 100 ¡æ), carbon atoms diffuse to form a carbon rich aggregation area, which makes the lattice more distorted, so the hardness is improved, as shown in B, C, D curves in Fig. 7-22. When tempered at 200-300 ¡æ, the change of hardness is related to the amount of retained austenite in the steel. The steel with more retained austenite quenched back in this temperature range, and the hardness changed little (Fig. 7-22d). The reason is that retained austenite decomposes and transforms into bainite in this temperature range. Although the hardness of martensite decreases with the increase of tempering temperature, the transformation of retained austenite into bainite counteracts the decrease of hardness. Therefore, the hardness of tp316h stainless steel tube tempered at 20-300 ¡æ decreases slowly or does not change. When tp316h stainless steel tube is heated at 250 ¡æ, the carbon content of martensite matrix is still about 0.25%, and there are dispersed precipitates ¦Å- Therefore, the hardness of tempered steel is still about HRC 60.
? ? When the tempering temperature is over 300 ¡æ, due to carbide precipitation and subsequent aggregation spheroidization and ¦Á The hardness of TP316L steel pipe is similar to that of TP316L steel pipe. However, the amount of carbides precipitated in tp316h stainless steel tube is relatively large, so the hardness is higher when tempered at the same temperature.
? ? Figure 7-23 shows the relationship between the tensile properties and tempering temperature of tp316h stainless steel pipe. Tempering before 300 ¡æ, due to the failure to eliminate the quenching macro stress, it shows brittle fracture and can not accurately measure the performance data. When tempered above 300 ¡æ, the mechanical properties of the steel are similar to those of low carbon steel, that is, the strength decreases and the plasticity and toughness increase with the increase of tempering temperature.