Bolting material

[Pavis1968]

Does anybody know the existance of A193 L7M, and the replacement of that instead of A320 L7M, I checked the ASTM A193 but such garde it was not mentioned on that.
My reference is thread378-176060

Regards,

 

[btrueblood]

Believe the poster in the referenced thread meant to say A193 grade B7M, which has the same alloy chemistry as the A320 grade L7M bolt. I don't know if the two bolts are mechanically equivalent (i.e. tested to the same tensile proof loads), but am fairly certain that the A193 bolts will not normally have undergone low-temperature Charpy tests, since A193 is a spec. for high-temperature service. Supplementary test S2 in A193 allows for impact tests, with the caveat "When testing temperatures are as low as those specified in Specification A 320/A 320M, bolting should be ordered to that specification in preference to this specification,"

 

[Pavis1968]

Btrueblood, thanks from your precise answer, that's right we don't have A193 L7M, it shall B7M, and also it is high temperature bolt material, in ASTM only in supplementary condition it is mentioned that if it is intended to be used in Low Temprature it should be charpy tested with referenced to ASTM A320, in my opinion it is better to avoid using this material for low temperature.