I shall use stud 1" diam. With 625

[abbver98]

I shall use stud 1" diam. With 625 alloy material for pressure vessel application. Vessel made with chrom-moly, T=500°C and high pressure. Would you indicate me the grade of nuts available in the market that goes with 625. (the mechanical properties have to be less 625's).

 

[johnp]

This is a case where you have to telephone your hardware or piping supplier. They will tell you what they can get locally.

You may even have to import the nuts from Japan or Scandinavia or some place. Try email direct to piping Vendors locally and overseas.

 

[johnp]

Do a search with "625" as your Keyword. Many of your questions will be answered.

 

[abbver98]

I'm in engineering. Purchasing failed to find the right supplier. I understand him because it's the first time we want to use such grade. I can indicate the grade of nuts but I fear that isn't available in markets. Between Enginnering and vendors there are light years !

 

[johnp]

In small quantities it is practical to fabricate out of plate or bar stock.

 

[abbver98]

Any help for this :
grade of nuts available in the market that goes with 625 !

 

[Flareman]

625 is a high Nickel/Chrome alloy with some Moly and is good for high temp and chlorine resistance. Do you need both of those characteristics in the nut or was 625 chosen (?) randomly (?) just for the temperature. Alloy 20 might be available on the market. This is also good for Chlorine but doesn't have the same high temperature capabilities.
However, I'm not a specialist in this area and there may be incompatibilities of expansion coefficients and surface hardness so you really should discuss it with a manufacturer or supply house as suggested by johnp. Have your service conditions at hand when you call.
You could also try calling the technical department metallurgists at INCO or Huntingdon to check on the compatibility.