Material selection for ASME bolts and nuts
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I’d like to ask the experts here: I’ve seen several American standard projects related to bolts and nuts, and in all of them it’s simply specified as 193 B7 or 194 2H. When are those other materials used? Are there any specifications similar to HG that I can consult for the relevant material selection standards? Thank you very much
When selecting the materials for bolts and nuts according to ASME standards, ASTM A193 Grade B7 bolts and ASTM A194 Grade 2H nuts are indeed commonly used; this combination is widely employed in various high-pressure and high-temperature applications due to its excellent mechanical properties and heat resistance. The choice of other materials usually depends on specific application environments and requirements, such as corrosion resistance, higher or lower temperature conditions, and different mechanical load requirements. Here are some examples of situations where other materials might be chosen: 1. **Corrosion resistance requirements**: In highly corrosive environments, stainless steel bolts and nuts such as ASTM A193 B8 (304 stainless steel) and B8M (316 stainless steel) may be used. 2. **Extreme temperatures**: For applications with higher temperatures, ASTM A193 B16 bolts may be chosen, as they can withstand higher temperatures. For low-temperature applications, ASTM A320 L7 bolts may be selected. 3. **Special mechanical properties**: In applications requiring higher strength, ASTM A193 B7M, B16, and similar materials can be chosen; these materials offer greater tensile strength. Regarding specific standards, ASME itself provides a great deal of information on material selection and application guidelines; you can refer to relevant sections such as ASME B31.1 (power piping), ASME B31.3 (process piping), and ASME Section VIII (pressure vessels). In addition, ASTM standards also detail the properties and application areas of various materials. If you need more specific selection guidelines or have particular application requirements, it is advisable to consult engineers or professionals in detail. They can provide the most suitable material recommendations based on the actual operating conditions. .
Basically, they are the national standard grades 35CrMo and 25CrMo, high-temperature bolts
Refer to Section 5.1(C) of ASME B16.5, Table 1.1-2, and Section 5.3; refer to ASME B31.3 for the requirements regarding gasket materials under various fluid conditions. The temperature range limits are given in Table A-2 or Table A-2M of B31.3
I’ve learned new knowledge again; thank you.
ASME SA-193/SA-193M – Alloy steel and stainless steel bolt materials for high temperature or high pressure applications as well as other special uses. ASME SA-194/SA-194M – Carbon steel and alloy steel nuts for bolts used in high pressure and high temperature environments