Thermal Expansion

[TurboME]

What is the best way to quantify the effects of using an ASTM A193 B16 alloy stud with a threaded 1018 steel flange?

The thermal expansion coefficient of the stud is about 14 F^-1 and 1018 is 6.7 F^-1. Is there a standard regarding this? Is this difference something I should be concerned about?

The application is an automotive exhaust system so temperatures will cycle over 1000 deg F.

 

[metengr]

There is little difference in the thermal expansion characteristics between an ASTM A 193 Grade B16 stud and low carbon steel. The coefficient of thermal expansion for a typical 1018 carbon steel is 7.72 micro-inch/inch at about 1000 deg F. In comparison, the ASTM A 193 Grade B16 will be approximately 7.5 micro-inch/inch at 1000 deg F.

The ASTM A 193 stud material is a low alloy steel containing vanadium. It can be used at 1000 deg F. The AISI Type 1018 will oxidize over time and not last long. Most exhaust systems today use a ferritic stainless steel versus carbon steel.

 

[TurboME]

Thanks for your reply. The data I looked at for B16 must have been in units of deg C not F.

 

[Screwman]

There are a number of OEMs that are going to A286 for exhaust studs to retain tensile strength at 1200 F while not having problems with corrosion and scaling. I don't know if you will need this much performance, but they work very well (although they are more expensive).

Dick